JP2013015186A - Control device of vehicular continuously variable transmission - Google Patents

Abstract

An object of the present invention is to suppress a deterioration in shift sustainability when a target thrust is shifted from a thrust range between a lower limit thrust and an upper limit thrust.
When the target thrust (Win ^* , Wout ^* ) is a shift that deviates from the upper and lower limit thrust range Wmin-max, the actual speed ratio γ is a predetermined speed ratio difference with respect to the post-shift target speed ratio γ ^* l. The target primary thrust Win ^* is set to one of the upper limit thrust Wmax and the lower limit thrust Wmin in the primary pulley 42 and the target secondary thrust Wout ^* is the other of the upper limit thrust Wmax and the lower limit thrust Wmin in the secondary pulley 46 until it approaches within γsyn. Thus, the shift is executed, so that the maximum shift performance at or near the limit at which the shift can actually be executed can be derived. Moreover, the continuation of the shift by feedforward control can be ensured.
[Selection] Figure 14

Description

  The present invention relates to a control device for a continuously variable transmission for a vehicle (belt type continuously variable transmission) that realizes a target speed ratio while preventing belt slippage by controlling an input side thrust and an output side thrust, respectively. .

  A pair of variable pulleys with variable effective diameters of an input side variable pulley (primary pulley, primary sheave) and an output side variable pulley (secondary pulley, secondary sheave); and a transmission belt wound between the pair of variable pulleys; And controlling the input side thrust (primary thrust) in the primary pulley and the output side thrust (secondary thrust) in the secondary pulley to prevent slippage of the transmission belt and to set the actual speed ratio as the target speed ratio. 2. Description of the Related Art A control device for a continuously variable transmission (hereinafter, continuously variable transmission) is well known. This is the shift control device for a belt-type continuously variable transmission described in Patent Document 1. In such a continuously variable transmission, for example, the target thrust (target secondary thrust) on one side (for example, the secondary side) of the primary pulley and the secondary pulley is at least necessary so that belt slip does not occur in the secondary pulley. Set to a critical slip limit thrust (necessary secondary thrust). In addition, the target thrust (target primary thrust) on the other side (for example, the primary side) of the primary pulley and the secondary pulley is used as a shift required thrust (for example, target shift) required for shift control according to the slip limit thrust. The balance thrust (steady thrust) that balances the target secondary thrust based on the thrust ratio (= secondary thrust / primary thrust) for maintaining the ratio, and the target shift speed when changing the gear ratio (Sum of shift difference thrust (transient thrust)). Then, by controlling the hydraulic pressure to each pulley so as to obtain the set thrust, the target gear ratio is realized while preventing belt slippage.

Japanese Patent No. 3042684

  By the way, the actual thrust of each pulley is, for example, the thrust sandwiched between the lower limit thrust, which is the above-mentioned slip limit thrust in each pulley, and the upper limit thrust, which is the upper limit limit thrust in each pulley determined by hardware constraints such as belt durability. It can be controlled within the range. Therefore, the limit value of the shift speed (that is, the maximum value that can be taken as the shift difference thrust) is determined by the thrust range. Therefore, for example, by continuing a certain target thrust for a predetermined time (for example, a time until a transient target speed ratio calculated to reach the final target speed ratio reaches the final target speed ratio), When the speed change control is performed so that the speed ratio reaches the final target speed ratio, if the target speed ratio and the target speed change exceed the limits, the target thrust calculated by the feedforward control is within the above thrust range. The target thrust is effectively blocked by the upper limit thrust or the lower limit thrust, and the gear shift difference thrust cannot be output as intended, or the target thrust that falls outside the above thrust range can be output as the actual thrust The absolute value is obstructed by the upper limit thrust or the lower limit thrust. Then, after the predetermined time has elapsed, the actual thrust ratio is not reached the final target gear ratio (or near the target gear ratio), but the target thrust is only the balance thrust, and the gear difference thrust is insufficient. Thus, there is a possibility that the shift by the feedforward control is difficult to be continued (shift is difficult to proceed), that is, the shift followability (followability to the target gear ratio) may be deteriorated. Note that the above-described problems are not known, and even if the target thrust is shifted from the thrust range defined by the upper and lower limit thrusts, the deterioration of the shift sustainability due to the feedforward control is suppressed and the shift is performed. It has not yet been proposed to appropriately ensure the following ability.

  The present invention has been made against the background of the above circumstances, and the object of the present invention is to provide a shift sustainability when the target thrust is shifted from the thrust range between the lower limit thrust and the upper limit thrust. An object of the present invention is to provide a control device for a continuously variable transmission for a vehicle that can suppress deterioration.

  The gist of the first invention for achieving the object is as follows: (a) a pair of variable pulleys having variable effective diameters of the input side variable pulley and the output side variable pulley, and the pair of variable pulleys; The actual transmission ratio is controlled while preventing slippage of the transmission belt by controlling the input side thrust in the input side variable pulley and the output side thrust in the output side variable pulley, respectively. A control device for a continuously variable transmission for a vehicle having a gear ratio, wherein (b) the input-side variable pulley and the output-side thrust based on the input-side thrust and the output-side thrust required for belt slip prevention and shift control Each of the target thrust of the output side variable pulley is set, and (c) at least one of the target thrusts is a lower limit thrust set in the input side variable pulley and the output side variable pulley, respectively. Up In the case of a shift that deviates from the thrust range between the thrust and the thrust, the target thrust of the input-side variable pulley is reduced in the input-side variable pulley until the actual speed ratio approaches within a predetermined speed ratio difference with respect to the target speed ratio. One of the upper limit thrust and the lower limit thrust is set, and the target thrust of the output side variable pulley is set to the other of the upper limit thrust and the lower limit thrust of the output side variable pulley to execute the shift.

  In this case, at least one of the target thrusts is a shift that deviates from the thrust range between the lower limit thrust and the upper limit thrust that are respectively set in the input side variable pulley and the output side variable pulley. In this case, the target thrust of the input side variable pulley is set to one of the upper limit thrust and the lower limit thrust of the input side variable pulley until the actual speed ratio approaches within a predetermined speed ratio difference with respect to the target speed ratio. Since the target thrust of the output side variable pulley is set to the other of the upper limit thrust and the lower limit thrust of the output side variable pulley and the speed change is executed, the maximum speed change performance near or the limit at which the actual speed change can be performed is achieved. It can be pulled out. That is, the shift can be executed at the maximum shift speed that can be currently achieved. Further, by executing the shift at the maximum shift speed until the actual speed ratio approaches the target speed ratio within a predetermined speed ratio difference, for example, the continuation of the shift by the feedforward control can be ensured. Therefore, when the target thrust is a shift that deviates from the thrust range between the lower limit thrust and the upper limit thrust, deterioration of the shift sustainability can be suppressed.

  Here, according to a second aspect of the present invention, in the control device for a continuously variable transmission for a vehicle according to the first aspect of the present invention, when the shift is out of the thrust range, the thrust range is used to advance the shift. This is a case where the actual gear ratio cannot reach the target gear ratio by the gear ratio change calculated based on the thrust that can actually be used. In this way, it is possible to suppress the deterioration of the shift sustainability when the target gear ratio cannot be reached with the thrust that can be actually used.

  According to a third aspect of the present invention, in the control device for a continuously variable transmission for a vehicle according to the first or second aspect of the invention, when the shift of the continuously variable transmission for the vehicle is a downshift, The target thrust of the input side variable pulley is set to the lower limit thrust in the input side variable pulley, and the target thrust of the output side variable pulley is set to the upper limit thrust in the output side variable pulley, while the vehicle continuously variable When the shift of the transmission is an upshift, the target thrust of the input side variable pulley is set to the upper limit thrust in the input side variable pulley, and the target thrust of the output side variable pulley is set in the output side variable pulley. The lower limit thrust is set. In this way, it is possible to appropriately draw out the maximum shift performance at or near the limit at which the actual shift can be performed. That is, it is possible to appropriately execute the shift at the maximum shift speed that can be currently achieved.

  According to a fourth aspect of the present invention, in the control device for a continuously variable transmission for a vehicle according to any one of the first to third aspects of the invention, the lower limit thrust is an actual transmission ratio and a value for the vehicle. The slip limit thrust required for preventing belt slippage calculated based on the input torque of the step transmission, and the upper limit thrust is an upper limit limit thrust determined based on at least belt durability. In this manner, the lower limit thrust is appropriately calculated to prevent belt slipping appropriately, and the upper limit thrust is appropriately determined to ensure belt durability and the like appropriately.

  According to a fifth aspect of the present invention, in the control device for a continuously variable transmission for a vehicle according to any one of the first to fourth aspects, the input-side variable pulley and the output-side variable pulley. As the target thrust on one side, the larger one of the lower limit thrust on one side and the thrust on the other side required for shift control calculated based on the lower limit thrust on the other side In addition to the selection, the target thrust on the other side is to set the thrust on the other side necessary for the shift control calculated based on the target thrust on the one side. In this way, on the one variable pulley side, the necessary thrust for preventing belt slippage in one variable pulley is secured, and the necessary thrust for preventing belt slippage in the other variable pulley. Is also secured. In addition, the target shift can be realized while preventing the belt slippage in the other variable pulley.

  According to a sixth aspect of the present invention, in the control device for a continuously variable transmission for a vehicle according to the fifth aspect of the present invention, the thrust required for the shift control is to realize a target speed ratio and a target speed. Necessary thrust. In this way, the thrust required for the shift control is appropriately calculated.

It is a figure explaining the schematic structure of the power transmission path | route which comprises the vehicle to which this invention is applied. It is a block diagram explaining the principal part of the control system provided in the vehicle. It is a hydraulic circuit diagram which shows the principal part regarding the hydraulic control regarding the transmission of a continuously variable transmission among hydraulic control circuits. It is a functional block diagram explaining the principal part of the control function of an electronic controller. It is a figure which shows an example for demonstrating a thrust required for transmission control. It is a block diagram which shows the control structure of a present Example. It is a figure which shows an example of the speed change map used when calculating | requiring the target input shaft rotational speed in the hydraulic control regarding the speed change of a continuously variable transmission. It is a figure which shows an example of the map previously calculated | required experimentally and memorize | stored in advance of engine rotation speed and engine torque by making intake air quantity into a parameter. It is a figure which shows an example of the map previously calculated | required experimentally as a predetermined operating characteristic of a torque converter, and was memorize | stored. It is a figure which shows an example of the thrust ratio map calculated | required experimentally beforehand and memorize | stored with the target speed ratio as a parameter and the reciprocal number of a safety factor, and a thrust ratio. It is a figure which shows an example of the difference thrust map calculated | required experimentally beforehand and memorize | stored with the speed change speed and the speed difference difference thrust. 7 is a flowchart for explaining a control operation for improving the fuel consumption by cutting a main part of the control operation of the electronic control unit, that is, a hydraulic margin on the primary pulley side where the hydraulic control accuracy is not good. It is a figure which shows an example of the upper limit thrust map calculated | required and memorize | stored beforehand with a gear ratio and an upper limit thrust. FIG. 6 is a flowchart for explaining a control operation for suppressing deterioration of the shift sustainability when the electronic control unit performs a shift in which the target thrust is out of the upper and lower limit thrust range, that is, when the target thrust is shifted from the upper and lower limit thrust range. This is the case when a shift is performed. FIG. 6 is a flowchart for explaining a control operation for suppressing deterioration of the shift sustainability when the main control operation of the electronic control unit, that is, the target thrust is shifted from the upper and lower limit thrust range, This is the case when a shift is performed. It is a time chart corresponding to the Example of FIG.

  In the present invention, preferably, the input-side thrust and the output-side thrust are each controlled by configuring a hydraulic control circuit so as to independently control pulley pressure applied to the input-side variable pulley and the output-side variable pulley. It can be controlled directly or indirectly.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a diagram illustrating a schematic configuration of a power transmission path from an engine 12 to a drive wheel 24 constituting a vehicle 10 to which the present invention is applied. In FIG. 1, for example, power generated by an engine 12 used as a driving force source for traveling is converted into a torque converter 14 as a fluid transmission device, a forward / reverse switching device 16, and a belt type as a continuously variable transmission for a vehicle. It is transmitted to the left and right drive wheels 24 through a continuously variable transmission (hereinafter referred to as continuously variable transmission (CVT)) 18, a reduction gear device 20, a differential gear device 22, and the like.

  The torque converter 14 includes a pump impeller 14p connected to the crankshaft 13 of the engine 12 and a turbine impeller 14t connected to the forward / reverse switching device 16 via a turbine shaft 30 corresponding to an output side member of the torque converter 14. The power is transmitted through the fluid. Further, a lockup clutch 26 is provided between the pump impeller 14p and the turbine impeller 14t. When the lockup clutch 26 is completely engaged, the pump impeller 14p and the turbine impeller 14t. Are rotated together. The pump impeller 14p controls the speed of the continuously variable transmission 18, generates belt clamping pressure in the continuously variable transmission 18, controls the torque capacity of the lock-up clutch 26, and controls the forward / reverse switching device 16. A mechanical oil pump 28 is connected which is generated when the engine 12 is rotationally driven by a working hydraulic pressure for switching the power transmission path and supplying lubricating oil to each part of the power transmission path of the vehicle 10. .

  The forward / reverse switching device 16 is mainly composed of a forward clutch C1 and a reverse brake B1 and a double pinion type planetary gear device 16p, and the turbine shaft 30 of the torque converter 14 is integrally connected to the sun gear 16s. The input shaft 32 of the continuously variable transmission 18 is integrally connected to the carrier 16c, while the carrier 16c and the sun gear 16s are selectively connected via the forward clutch C1, and the ring gear 16r is connected to the reverse brake B1. The housing is selectively fixed to the housing 34 as a non-rotating member. The forward clutch C1 and the reverse brake B1 correspond to an intermittent device, both of which are hydraulic friction engagement devices that are frictionally engaged by a hydraulic cylinder.

  In the forward / reverse switching device 16 configured as described above, when the forward clutch C1 is engaged and the reverse brake B1 is released, the forward / reverse switching device 16 is brought into an integral rotation state, thereby causing the turbine shaft 30 to rotate. Is directly connected to the input shaft 32, and a forward power transmission path is established (achieved), so that the driving force in the forward direction is transmitted to the continuously variable transmission 18 side. When the reverse brake B1 is engaged and the forward clutch C1 is released, the forward / reverse switching device 16 establishes (achieves) the reverse power transmission path, and the input shaft 32 is connected to the turbine shaft 30. On the other hand, it is rotated in the opposite direction, and the driving force in the reverse direction is transmitted to the continuously variable transmission 18 side. When both the forward clutch C1 and the reverse brake B1 are released, the forward / reverse switching device 16 is in a neutral state (power transmission cut-off state) in which power transmission is cut off.

The engine 12 is constituted by an internal combustion engine such as a gasoline engine or a diesel engine. This intake pipe 36 of the engine 12, the electronic throttle valve 40 for electrically controlling the intake air quantity Q _AIR of the engine 12 using the throttle actuator 38 is provided.

  The continuously variable transmission 18 is an input-side variable pulley (primary pulley, primary sheave) 42 that is an input-side member that is provided on the input shaft 32 and is an output-side member that is provided on the output shaft 44. A pair of variable pulleys 42, 46 of an output side variable pulley (secondary pulley, secondary sheave) 46 having a variable diameter, and a transmission belt 48 wound between the pair of variable pulleys 42, 46; Power is transmitted through a frictional force between the pair of variable pulleys 42 and 46 and the transmission belt 48.

  The primary pulley 42 is provided with a fixed rotating body (fixed sheave) 42 a as an input side fixed rotating body fixed to the input shaft 32, and is not rotatable relative to the input shaft 32 around the axis and is movable in the axial direction. A movable rotating body (movable sheave) 42b as an input side movable rotating body, and an input side thrust (primary thrust) Win (= primary pressure Pin × pressure receiving area) in the primary pulley 42 for changing the V groove width between them. ) And an input side hydraulic cylinder (primary side hydraulic cylinder) 42c as a hydraulic actuator. The secondary pulley 46 is fixed to the output shaft 44, and is a fixed rotating body (fixed sheave) 46a as an output-side fixed rotating body. The secondary pulley 46 is not rotatable relative to the output shaft 44 and is movable in the axial direction. A movable rotating body (movable sheave) 46b as an output-side movable rotating body provided, and an output-side thrust (secondary thrust) Wout (= secondary pressure Pout ×) in the secondary pulley 46 for changing the V groove width therebetween. And an output side hydraulic cylinder (secondary side hydraulic cylinder) 46c as a hydraulic actuator for providing a pressure receiving area).

Then, the primary pressure Pin, which is the hydraulic pressure to the primary hydraulic cylinder 42c, and the secondary pressure Pout, which is the hydraulic pressure to the secondary hydraulic cylinder 46c, are independently regulated by the hydraulic control circuit 100 (see FIG. 3). The primary thrust Win and the secondary thrust Wout are directly or indirectly controlled. As a result, the V-groove width of the pair of variable pulleys 42 and 46 is changed, and the engagement diameter (effective diameter) of the transmission belt 48 is changed, and the transmission gear ratio (gear ratio) γ (= input shaft rotational speed N _IN / output shaft). The rotational speed N _OUT ) is continuously changed, and the frictional force (belt clamping pressure) between the pair of variable pulleys 42 and 46 and the transmission belt 48 is controlled so that the transmission belt 48 does not slip. . In this way, by controlling the primary thrust Win and the secondary thrust Wout, the actual transmission ratio (actual transmission ratio) γ is set as the target transmission ratio γ ^* while preventing the transmission belt 48 from slipping. The input shaft rotational speed N _IN is the rotational speed of the input shaft 32, and the output shaft rotational speed N _OUT is the rotational speed of the output shaft 44. In this embodiment, as can be seen from FIG. 1, the input shaft rotation speed N _IN is the same as the rotation speed of the primary pulley 42, and the output shaft rotation speed N _OUT is the same as the rotation speed of the secondary pulley 46.

In the continuously variable transmission 18, for example, when the primary pressure Pin is increased, the V groove width of the primary pulley 42 is narrowed to reduce the gear ratio γ, that is, the continuously variable transmission 18 is upshifted. Further, when the primary pressure Pin is lowered, the V groove width of the primary pulley 42 is widened to increase the gear ratio γ, that is, the continuously variable transmission 18 is downshifted. Therefore, when the V groove width of the primary pulley 42 is minimized, the minimum speed ratio γmin (the highest speed side speed ratio, the highest Hi) is formed as the speed ratio γ of the continuously variable transmission 18. Further, when the V-groove width of the primary pulley 42 is maximized, the maximum speed ratio γmax (the lowest speed side speed ratio, the lowest) is formed as the speed ratio γ of the continuously variable transmission 18. The primary pressure Pin (primary thrust Win also agrees) and the secondary pressure Pout (secondary thrust Wout agrees) are prevented from slipping (belt slipping) of the transmission belt 48, while the primary thrust Win and the secondary thrust Wout Therefore, the target speed ratio γ ^* is realized, and the target speed change is not realized only by one pulley pressure (the thrust is also agreed).

  FIG. 2 is a block diagram illustrating a main part of a control system provided in the vehicle 10 in order to control the engine 12, the continuously variable transmission 18, and the like. In FIG. 2, the vehicle 10 is provided with an electronic control device 50 including a control device for a vehicle continuously variable transmission related to, for example, shift control of the continuously variable transmission 18. The electronic control unit 50 includes, for example, a so-called microcomputer having a CPU, a RAM, a ROM, an input / output interface, and the like. The CPU uses a temporary storage function of the RAM and follows a program stored in the ROM in advance. Various controls of the vehicle 10 are executed by performing signal processing. For example, the electronic control unit 50 performs output control of the engine 12, shift control of the continuously variable transmission 18, belt clamping pressure control, torque capacity control of the lockup clutch 26, and the like. The engine control, the continuously variable transmission 18 and the lockup clutch 26 are controlled separately.

The electronic control unit 50, rotation angle (position) A _CR and a signal representative of the rotational speed (engine rotational speed) N _E of the engine 12 of the crankshaft 13 detected by the engine rotational speed sensor 52, a turbine speed sensor 54 A signal representing the detected rotational speed (turbine rotational speed) _NT of the turbine shaft 30, and a signal representing the input shaft rotational speed N _IN which is the input rotational speed of the continuously variable transmission 18 detected by the input shaft rotational speed sensor 56. , A signal representing the output shaft rotational speed N _OUT that is the output rotational speed of the continuously variable transmission 18 corresponding to the vehicle speed V detected by the output shaft rotational speed sensor 58, the throttle of the electronic throttle valve 40 detected by the throttle sensor 60 signal representing the valve opening theta _TH, a signal representing the cooling water temperature TH _W of the engine 12 detected by a coolant temperature sensor 62, Signal representing the intake air quantity Q _AIR of the engine 12 detected by the incoming air flow sensor 64, the accelerator opening Acc is an operation amount of the accelerator pedal as an acceleration demand of the detected driver by the accelerator opening sensor 66 A signal indicating a brake-on _BON indicating a state in which a foot brake, which is a service brake detected by the foot brake switch 68, is operated, a hydraulic oil for the continuously variable transmission 18 detected by the CVT oil temperature sensor 70, and the like. signal representative of the oil temperature _{TH oIL,} lever lever position (operation _position) of the shift lever detected by the position sensor 72 signals representative of _{P SH,} the battery temperature detected by the battery sensor 76 _{TH BAT} and the battery output current (battery signal representing the charging and discharging _{current) I BAT} and the battery voltage _{V BAT,} Secondary Signal or the like representing the secondary pressure Pout is a hydraulic pressure supplied to the secondary pulley 46 detected by the re-pressure sensor 78, are supplied. The electronic control unit 50 sequentially calculates the state of charge (charge capacity) SOC of the battery (power storage device) based on, for example, the battery temperature TH _BAT , the battery charge / discharge current I _BAT , and the battery voltage V _BAT . Further, the electronic control unit 50 sequentially calculates the actual speed ratio γ (= N _IN / N _OUT ) of the continuously variable transmission 18 based on, for example, the output shaft rotational speed N _OUT and the input shaft rotational speed N _IN .

The electronic control unit 50 also outputs an engine output control command signal S _E for output control of the engine 12, a hydraulic control command signal S _CVT for hydraulic control related to the shift of the continuously variable transmission 18, and the like. The Specifically, as the engine output control command signal S _E, to control the amount of fuel injected from the throttle signal and the fuel injection device 80 for controlling the opening and closing of the electronic throttle valve 40 by driving the throttle actuator 38 And an ignition timing signal for controlling the ignition timing of the engine 12 by the ignition device 82 are output. Further, as the hydraulic control command signal S _CVT , a command signal for driving the linear solenoid valve SLP for regulating the primary pressure Pin, a command signal for driving the linear solenoid valve SLS for regulating the secondary pressure Pout, and the line hydraulic pressure P A command signal for driving the linear solenoid valve SLT that controls _L is output to the hydraulic control circuit 100.

  FIG. 3 is a hydraulic circuit diagram showing a main part related to the hydraulic control related to the shift of the continuously variable transmission 18 in the hydraulic control circuit 100. 3, the hydraulic control circuit 100 includes, for example, an oil pump 28, a primary pressure control valve 110 that regulates the primary pressure Pin, a secondary pressure control valve 112 that regulates the secondary pressure Pout, a primary regulator valve (line hydraulic pressure regulating valve) 114, A modulator valve 116, a linear solenoid valve SLT, a linear solenoid valve SLP, a linear solenoid valve SLS, and the like are provided.

Line pressure P _L, for example the output from the oil pump 28 (the generation) by the hydraulic pressure as a source pressure, engine load based on the control oil pressure P _SLT is the output oil pressure of the linear solenoid valve SLT by the primary regulator valve 114 of the relief type The pressure is adjusted to a value according to the above. Specifically, the line pressure P _L based on the control pressure P _SLT of hydraulic pressure by adding a predetermined margin (margin) to the hydraulic pressure of higher primary pressure Pin and the secondary pressure Pout is set so as to obtain It is regulated. Therefore, the is avoided that the line pressure P _L as the original pressure in pressure regulating operation of the primary pressure control valve 110 and the secondary pressure control valve 112 is insufficient, the line pressure P _L from being unnecessarily high It is possible. Moreover, modulator pressure _{P M,} the control hydraulic pressure _{P SLT} is controlled by the electronic control unit 50, the linear solenoid valve control oil pressure _{P SLP} is a SLP of the output hydraulic pressure, and the control oil pressure _{P SLS} is the output oil pressure of the linear solenoid valve SLS be comprised between each source pressure and pressure is adjusted to a constant pressure by a modulator valve 116 to line pressure P _L as source pressure.

Primary pressure control valve 110, the spool valve element 110a that allows supplying the line pressure _{P L} by opening and closing an input port 110i by being movable in the axial direction from the input port 110i to the primary pulley 42 via an output port 110t And a spring 110b as an urging means for urging the spool valve element 110a in the valve opening direction, and a control oil pressure P _SLP for accommodating the spring 110b and applying a thrust force in the valve opening direction to the spool valve element 110a. an oil chamber 110c that accepts a feedback oil chamber 110d that accepts line pressure _{P L} which is output from the output port 110t to apply thrust in the valve closing direction to the spool valve element 110a, the valve closing direction to the spool valve element 110a oil accept modulator pressure P _M to apply a thrust force Chamber 110e. The primary pressure control valve 110 configured as described above, for example, the control for supplying hydraulic pressure P _SLP to the primary hydraulic cylinder 42c of the primary pulley 42 to control the line pressure P _L to regulation control as a pilot pressure. As a result, the primary pressure Pin supplied to the primary hydraulic cylinder 42c is controlled. For example, when the control hydraulic pressure P _SLP output from the linear solenoid valve SLP increases from a state where a predetermined hydraulic pressure is supplied to the primary hydraulic cylinder 42c, the spool valve element 110a of the primary pressure control valve 110 is moved upward in FIG. Moving. Thereby, the primary pressure Pin to the primary side hydraulic cylinder 42c increases. On the other hand, when the control hydraulic pressure P _SLP output from the linear solenoid valve SLP decreases from the state in which the predetermined hydraulic pressure is supplied to the primary hydraulic cylinder 42c, the spool valve element 110a of the primary pressure control valve 110 is moved downward in FIG. Move to the side. Thereby, the primary pressure Pin to the primary side hydraulic cylinder 42c falls.

  Further, an orifice 120 is provided in the oil passage 118 between the primary hydraulic cylinder 42c and the primary pressure control valve 110 for the purpose of fail-safe or the like. By providing the orifice 120, for example, even if the linear solenoid valve SLP fails, the internal pressure of the primary hydraulic cylinder 42c is not suddenly reduced. Thereby, for example, sudden deceleration of the vehicle 10 due to a failure of the linear solenoid valve SLP is suppressed.

Secondary pressure control valve 112 permits the supply of line pressure P _L by opening and closing an input port 112i by being movable in the axial direction from the input port 112i to the secondary pulley 46 via an output port 112t as secondary pressure Pout The spool valve element 112a, the spring 112b as an urging means for urging the spool valve element 112a in the valve opening direction, and the spring 112b for receiving the spring 112b and applying a thrust force in the valve opening direction to the spool valve element 112a An oil chamber 112c that receives the control hydraulic pressure P _SLS , a feedback oil chamber 112d that receives the secondary pressure Pout output from the output port 112t in order to apply thrust in the valve closing direction to the spool valve element 112a, and a spool valve element 112a that are closed. Modular to provide thrust in the valve direction And an oil chamber 112e that accepts data hydraulic _{P M.} The secondary pressure control valve 112 configured as described above, for example, supplies the control oil pressure P _SLS on the secondary side hydraulic cylinder 46c of the secondary pulley 46 by the line pressure P _L pressure regulation and control as a pilot pressure. Thereby, the secondary pressure Pout supplied to the secondary hydraulic cylinder 46c is controlled. For example, when the control hydraulic pressure P _SLS output from the linear solenoid valve SLS increases from the state in which the predetermined hydraulic pressure is supplied to the secondary hydraulic cylinder 46c, the spool valve element 112a of the secondary pressure control valve 112 is moved upward in FIG. Moving. Thereby, the secondary pressure Pout to the secondary side hydraulic cylinder 46c increases. On the other hand, when the control hydraulic pressure P _SLS output from the linear solenoid valve SLS decreases from the state in which the predetermined hydraulic pressure is supplied to the secondary hydraulic cylinder 46c, the spool valve element 112a of the secondary pressure control valve 112 is lowered in FIG. Move to the side. Thereby, the secondary pressure Pout to the secondary side hydraulic cylinder 46c falls.

  Further, an orifice 124 is provided in the oil passage 122 between the secondary hydraulic cylinder 46c and the secondary pressure control valve 112 for the purpose of fail-safe or the like. By providing this orifice 124, for example, even if the linear solenoid valve SLS breaks down, the internal pressure of the secondary hydraulic cylinder 46c is not suddenly reduced. Thereby, for example, belt slippage due to failure of the linear solenoid valve SLS is prevented.

  In the hydraulic control circuit 100 configured as described above, for example, the primary pressure Pin regulated by the linear solenoid valve SLP and the secondary pressure Pout regulated by the linear solenoid valve SLS do not cause belt slip and are unnecessary. The pair of variable pulleys 42 and 46 is controlled to generate a belt clamping pressure that does not increase. Further, as will be described later, the thrust ratio τ (= Wout / Win) of the pair of variable pulleys 42 and 46 is changed by the mutual relationship between the primary pressure Pin and the secondary pressure Pout. The speed ratio γ is changed. For example, the gear ratio γ is increased as the thrust ratio τ is increased (that is, the continuously variable transmission 18 is downshifted).

FIG. 4 is a functional block diagram for explaining a main part of the control function by the electronic control unit 50. FIG at 4, the engine output control unit, that is, the engine output control unit 130, for example engine 12 throttle signal and the injection signal and an ignition timing signal throttle actuator 38 and the fuel respectively the engine output control command signal S _E, such as for output control of the Output to the injection device 80 and the ignition device 82. For example, the engine output control means 130 sets a target engine torque T _E ^* for obtaining a driving force (driving torque) corresponding to the accelerator opening Acc, and throttles the target engine torque T _E ^* so as to obtain the target engine torque T _E ^*. In addition to controlling the opening and closing of the electronic throttle valve 40 by the actuator 38, the fuel injection amount is controlled by the fuel injection device 80, and the ignition timing is controlled by the ignition device 82.

The continuously variable transmission control unit, that is, the continuously variable transmission control means 132, for example, performs primary pressure so as to achieve the target gear ratio γ ^* of the continuously variable transmission 18 while preventing belt slippage of the continuously variable transmission 18. A primary command pressure Pintgt as a command value of Pin (or target primary pressure Pin ^* ) and a secondary command pressure Pouttgt as a command value of secondary pressure Pout (or target secondary pressure Pout ^* ) are determined, and the primary command pressure Pintgt and secondary The command pressure Pouttgt is output to the hydraulic control circuit 100.

By the way, the hydraulic control circuit 100 of the present embodiment has an actual secondary pressure that acts on the secondary pulley 46 (secondary hydraulic cylinder 46c) only on the secondary pulley 46 side, which is one side of the pair of variable pulleys 42 and 46. A secondary pressure sensor 78 is provided as a hydraulic pressure sensor for detecting Pout. Therefore, the continuously variable transmission control means 132 executes feedback control in which the detected value of the secondary pressure sensor 78 (a signal indicating the actual secondary pressure Pout) is set to the target secondary pressure Pout ^* corresponding to the target secondary thrust Wout ^* , for example. be able to. As a result, the thrust (pulley pressure) can be accurately controlled on the secondary pulley 46 side as compared to the primary pulley 42 side on which no hydraulic sensor is provided. That is, in this embodiment, the hydraulic control circuit that can control the thrust (pulley pressure) with high accuracy by comparing the secondary pulley 46 that is one of the primary pulley 42 and the secondary pulley 46 with the primary pulley 42 that is the other. 100 is provided.

Therefore, the thrust required for preventing belt slip with the minimum necessary thrust (necessary thrust), that is, the belt slip limit thrust (hereinafter referred to as slip limit thrust), which is the thrust immediately before the occurrence of belt slip, is set as the target thrust. If the primary pulley 42 side has a relatively poor hydraulic control accuracy (that is, feedback control cannot be performed based on the deviation between the detected value of the hydraulic sensor and the target value), the hydraulic command value (primary It is necessary to add the thrust corresponding to the hydraulic pressure variation, which is the difference between the command pressure (Pintgt) and the actual hydraulic pressure (actual primary pressure Pin), to the slip limit thrust. Then, the primary pulley 42 side hydraulic pressure variation is determined from the mutual relationship between the primary pressure Pin (primary thrust Win) and the secondary pressure Pout (secondary thrust Wout) based on the thrust ratio τ (= Wout / Win) for realizing the target shift. The target secondary thrust Wout ^* must also be increased corresponding to the thrust corresponding to, and the fuel consumption may deteriorate. Even if a hydraulic sensor is not provided, the thrust can be corrected by feedback control based on the gear ratio deviation Δγ (= γ ^* −γ) between the target gear ratio γ ^* and the actual gear ratio γ. Regarding the realization of the shift, the hydraulic control accuracy is not necessarily good.

Therefore, in this embodiment, for example, on the secondary pulley 46 side where the hydraulic control accuracy is relatively good, not only the slip limit thrust on the secondary pulley 46 side is secured, but also the slip limit thrust on the primary pulley 42 side is secured. That is, the belt torque capacity guarantee of both pulleys 42 and 46 is realized. Further, on the primary pulley 42 side where the hydraulic control accuracy is relatively inferior, the target primary thrust Win ^* corresponding to the target secondary thrust Wout ^* for guaranteeing the prevention of the belt slip is set, thereby realizing the target shift. At this time, feedback control based on the gear ratio deviation Δγ is executed in order to avoid fuel consumption deterioration due to the hydraulic pressure variation on the primary pulley 42 side.

Specifically, the continuously variable transmission control means 132 is, for example, a secondary pulley side slip limit thrust Woutlmt that is a slip limit thrust on the secondary pulley 46 side, and a primary pulley side slip limit thrust that is a slip limit thrust on the primary pulley 42 side. The larger one of the secondary pulley side shift control thrust Woutsh that is the thrust on the secondary pulley 46 side necessary for the shift control calculated based on Winlmt is selected as the target secondary thrust Wout ^* . Further, the continuously variable transmission control means 132, for example, a primary pulley side shift control thrust Winsh, which is a thrust on the primary pulley 42 side necessary for shift control calculated based on the selected target secondary thrust Wout ^* , Set as target primary thrust Win ^* . Further, the continuously variable transmission control means 132 performs the target primary thrust Win ^* (that is, the primary pulley side speed change) by feedback control of the primary thrust Win based on the speed ratio deviation Δγ between the target speed ratio γ ^* and the actual speed ratio γ, for example. The control thrust (Winsh) is corrected.

The gear ratio deviation Δγ may be a deviation between the target value and the actual value in the parameter corresponding to the gear ratio γ on a one-to-one basis. For example, instead of the gear ratio deviation Δγ, the deviation ΔXin (= Xin ^* −Xin) between the target pulley position Xin ^* on the primary pulley 42 side and the actual pulley position Xin (see FIG. 3), the target pulley position on the secondary pulley 46 side. Deviation ΔXout (= Xout ^* −Xout) between Xout ^* and actual pulley position Xout (see FIG. 3), deviation ΔRin between target belt engagement diameter Rin ^* on primary pulley 42 side and actual belt engagement diameter Rin (see FIG. 3) (= Rin ^* −Rin), deviation ΔRout (= Rout ^* −Rout) between the target belt engagement diameter Rout ^* on the secondary pulley 46 side and the actual belt engagement diameter Rout (see FIG. 3), the target input shaft rotational speed N _IN ^* A deviation ΔN _IN (= N _IN ^* −N _IN ) between the actual input shaft rotational speed N _IN and the like can be used.

Further, the thrust required for the shift control is, for example, a thrust necessary for realizing the target shift, and a thrust required for realizing the target gear ratio γ ^* and the target shift speed. The shift speed is, for example, the change amount dγ (= dγ / dt) of the speed ratio γ per unit time. In this embodiment, the pulley position movement amount (dX / dNelm) per belt element (block) is used. Defined (dX: axial displacement of pulley per unit time [mm / ms], dNelm: number of elements (blocks) biting into pulley per unit time [piece / ms]). Therefore, the shift speed (dX / dNelm) is represented by a primary shift speed (dXin / dNelmin) and a secondary shift speed (dXout / dNelmout). Specifically, the primary thrust Win and the secondary thrust Wout in a steady state (a state in which the speed ratio γ is constant) are referred to as balance thrust (steady thrust) Wbl (for example, primary balance thrust Winbl and secondary balance thrust Woutbl). Is the thrust ratio τ (= Woutbl / Winbl). Further, when the primary thrust Win and the secondary thrust Wout are in a steady state in which a constant gear ratio γ is maintained, if a certain thrust is added to or subtracted from any one of the pair of variable pulleys 42 and 46, the steady state is lost. As a result, the speed ratio γ changes, and a speed change speed (dX / dNelm) corresponding to the magnitude of the thrust added or subtracted is generated. This added or subtracted thrust is referred to as shift difference thrust (transient thrust) ΔW (for example, primary shift difference thrust ΔWin and secondary shift difference thrust ΔWout). Therefore, the thrust required for the speed change control is, when one thrust is set, the target speed ratio γ ^* corresponding to one thrust based on the thrust ratio τ for maintaining the target speed ratio γ ^* . The other balance thrust Wbl to be realized and the target shift speed (for example, primary target shift speed (dXin / dNelmin) ^* and secondary target shift speed (dXout / dNelmout) ^* ) when the target speed ratio γ ^* is changed. This is the sum of the shift difference thrust ΔW for realizing. Further, the differential thrust ΔW when the target gear shift is realized on the primary pulley 42 side, that is, the primary shift differential thrust ΔWin converted on the primary pulley side is (ΔWin> 0) in the upshift state, and the downshift state (ΔWin <0), and in a steady state with a constant gear ratio, (ΔWin = 0). Further, the differential thrust ΔW when the target shift is realized on the secondary pulley 46 side, that is, the secondary shift differential thrust ΔWout converted to the secondary pulley side is (ΔWout <0) in the upshift state, and the downshift state (ΔWout> 0), and in a steady state with a constant gear ratio, (ΔWout = 0).

FIG. 5 is a diagram for explaining the thrust required for the shift control. FIG. 5 shows the primary thrust Win set when the target upshift is realized on the primary pulley 42 side when the secondary thrust Wout is set so as to realize belt slip prevention on the secondary pulley 46 side, for example. An example is shown. In FIG. 5A, before the time t1 or after the time t3, the target gear ratio γ ^* is in a constant steady state and ΔWin = 0, so the primary thrust Win is the primary balance thrust Winbl (= Wout / τ). It becomes only. Further, since the target gear ratio γ ^* is in the upshift state from the time point t1 to the time point t3, the thrust relationship diagram at the time point t2 in FIG. 5A shown in FIG. 5B is represented. Further, the primary thrust Win is the sum of the primary balance thrust Winbl and the primary shift difference thrust ΔWin. The shaded portion of each thrust shown in FIG. 5 (b) corresponds to each balance thrust Wbl for maintaining the target speed ratio γ ^* at time t2 in FIG. 5 (a).

FIG. 6 is a block diagram showing a control structure for achieving both a target shift and belt slip prevention with the minimum necessary thrust when the secondary pressure sensor 78 is provided only on the secondary pulley 46 side. 6, the input torque T _IN of the target gear ratio gamma ^* and the continuously variable transmission 18, for example, sequentially calculated by the CVT control unit 132.

Specifically, the continuously variable transmission control means 132 determines the post-shift target speed ratio γ ^* l, which is the speed ratio γ to be achieved after the speed change of the continuously variable transmission 18. The continuously variable transmission control means 132 uses the accelerator opening Acc as shown in FIG. 7 as a parameter, for example, to obtain and store the relationship between the output shaft rotational speed N _OUT and the target input shaft rotational speed N _IN ^* that has been obtained in advance (transmission speed). The target input shaft rotational speed N _IN ^* is set based on the vehicle state indicated by the actual output shaft rotational speed N _OUT and the accelerator opening Acc from the map). Then, the continuously variable transmission control means 132 calculates a post-shift target gear ratio γ ^* l (= N _IN ^* / N _OUT ) based on the target input shaft rotational speed N _IN ^* . The shift map in FIG. 7 corresponds to a shift condition, and the target input shaft rotational speed N _IN ^* that sets a larger gear ratio γ is set as the output shaft rotational speed N _OUT is smaller and the accelerator opening Acc is larger. ing. This post-shift target speed ratio γ ^* l is determined within the range of the minimum speed ratio γmin (highest speed gear ratio, highest Hi) and the maximum speed ratio γmax (lowest speed gear ratio, lowest Low) of the continuously variable transmission 18. . Then, the continuously variable transmission control means 132 determines the speed ratio γ before the start of the speed change and the target speed ratio γ after the speed change from the relationship that has been experimentally obtained and stored in advance so as to realize a quick and smooth speed change, for example. ^{* Based on} l and the difference between them, the target speed ratio γ ^* is determined as the target value of the transient speed ratio γ during the speed change. For example, the continuously variable transmission control means 132 is a smooth curve (for example, a first-order lag curve) that changes the target speed ratio γ ^* that is sequentially changed during the shift from the start of the shift toward the post-shift target speed ratio γ ^* l. And a second order delay curve) as a function of elapsed time. That is, the continuously variable transmission control means 132 sequentially shifts the speed ratio γ before the start of the shift from the speed ratio γ before the start of the shift to the target speed ratio γ ^* 1 after the shift during the shift of the continuously variable transmission 18. Change the target gear ratio γ ^* . Further, the CVT control unit 132, when determining the target gear ratio gamma ^* as a function of the elapsed time, the target shift speed during shifting from the target gear ratio gamma ^* (primary target shift speed (dXin / dNelmin) ^* And secondary target shift speed (dXout / dNelmout) ^* ) are calculated. For example, when the gear shift is completed and the target gear ratio γ ^* is in a constant steady state, the target gear shift speed becomes zero.

Further, the continuously variable transmission control means 132, for example, a pump torque T is an input torque of the turbine torque T _{T /} torque converter 14 is the output torque of the engine torque T _E to the torque converter 14 of the torque ratio t (= torque converter 14 as a torque multiplied by _{P) (= T E × t} ), and calculates the input torque _{T iN} of the continuously variable transmission 18. Further, the continuously variable transmission control means 132 uses, for example, the intake air amount Q _AIR (or the corresponding throttle valve opening θ _TH or the like) as a required load for the engine 12 as a parameter, and the engine speed N _E and the engine torque T _E. experimentally determined in advance are shown in FIG. 8 which is stored in relationship with (map, the engine torque characteristic diagram) from the estimated engine torque T _E es based on the intake air quantity Q _aIR and the engine rotational speed N _E Then, the engine torque _TE is calculated. Alternatively, the engine torque T _E, for example the actual output torque (actual engine torque) of the engine 12 detected by such a torque sensor T _E or the like may be used. The torque ratio t of the torque converter 14 is the speed ratio e of the torque converter 14 (= the turbine rotational speed N _T that is the output rotational speed of the torque converter 14 / the pump rotational speed N _P that is the input rotational speed of the torque converter 14. 9 is a function of the engine speed N _E )). For example, the relationship between the speed ratio e, the torque ratio t, the efficiency η, and the capacity coefficient C obtained and stored in advance experimentally (see FIG. 9). Based on the actual speed ratio e, the continuously variable transmission control means 132 calculates from a map and a predetermined operating characteristic diagram of the torque converter 14. The estimated engine torque T _E es is calculated so as to represent the actual engine torque T _E itself, and unless otherwise distinguished from the actual engine torque T _E , the estimated engine torque T _E es is calculated as the actual engine torque T _E es. It shall be treated as T _E. Accordingly, the estimated engine torque T _E es includes the actual engine torque T _E.

  The continuously variable transmission control means 132 includes, for example, a limit thrust calculation unit that calculates a slip limit thrust Wlmt, that is, a limit thrust calculation unit 134, a steady thrust calculation unit that calculates a balance thrust Wbl, that is, a steady thrust calculation unit 136, A differential thrust calculation unit for calculating the differential thrust ΔW, that is, a differential thrust calculation unit 138, and an FB control amount calculation unit for calculating the feedback control amount Winfb, that is, an FB control amount calculation unit 140 are provided.

In block B1 and block B2 in FIG. 6, limit thrust calculation means 134, for example, calculates the slip limit thrust Wlmt based on the input torque T _IN of the actual speed ratio γ and the continuously variable transmission 18. Specifically, the limit thrust calculating means 134 calculates the input torque T _IN of the continuously variable transmission 18 as the input torque of the primary pulley 42 and the input torque of the secondary pulley 46 from the following expressions (1) and (2). Output torque T _OUT of the continuously variable transmission 18, sheave angle α of the variable pulleys 42, 46, a predetermined element-to-pulley friction coefficient μin on the primary pulley 42 side, and a predetermined element-to-pulley friction coefficient on the secondary pulley 46 side. The belt engagement diameter Rin on the primary pulley 42 side uniquely calculated from μout and the actual transmission ratio γ, and the belt engagement diameter Rout on the secondary pulley 46 side uniquely calculated from the actual transmission ratio γ (see FIG. 3 above). Based on the above, the secondary pulley side slip limit thrust Woutlmt and the primary pulley side slip limit thrust Winlmt are respectively calculated. Note that T _OUT = γ × Tin = (Rout / Rin) × Tin.
Woutlmt = (T _OUT × cos α) / (2 × μout × Rout)
= (Tin × cosα) / (2 × μout × Rin) (1)
Winlmt = (Tin × cosα) / (2 × μin × Rin) (2)

In block B3 and block B6 of FIG. 6, the steady thrust calculating means 136 calculates, for example, a secondary balance thrust Woutbl corresponding to the primary pulley side slip limit thrust Winlmt and a primary balance thrust Winbl corresponding to the target secondary thrust Wout ^*. . Specifically, the steady thrust calculating means 136 corresponds to the reciprocal SFin ⁻¹ (= Winlmt / Win) of the primary safety factor SFin (= Win / Winlmt) and the primary pulley 42 side with the target speed ratio γ ^* as a parameter. A target shift that is sequentially calculated from, for example, a relationship (thrust ratio map) as shown in FIG. 10 (a), which is experimentally obtained and stored in advance with the thrust ratio τin when the thrust on the secondary pulley 46 side is calculated. The thrust ratio τin is calculated based on the ratio γ ^* and the reciprocal SFin ⁻¹ of the primary safety factor. Then, the steady thrust calculating means 136 calculates the secondary balance thrust Woutbl based on the primary pulley side slip limit thrust Winlmt and the thrust ratio τin from the following equation (3). Further, the steady thrust calculating means 136 uses the target speed ratio γ ^* as a parameter and the reciprocal SFout ⁻¹ (= Woutlmt / Wout) of the secondary-side safety factor SFout (= Wout / Woutlmt) and the primary pulley 42 corresponding to the secondary pulley 46 side. The target gear ratio γ ^* calculated sequentially from, for example, the relationship (thrust ratio map) as shown in FIG. 10B, which is experimentally obtained and stored in advance with the thrust ratio τout when calculating the thrust on the side. And thrust ratio (tau) out is calculated based on the reciprocal number SFout- ¹ of a secondary side safety factor. Then, the steady thrust calculating means 136 calculates the primary balance thrust Winbl based on the target secondary thrust Wout ^* and the thrust ratio τout from the following equation (4). Since the input torque T _IN and the output torque T _OUT are negative values when driven, the reciprocals SFin ⁻¹ and SFout ^{−1 of the} above safety factors are also negative values when driven. Further, the reciprocal numbers SFin ⁻¹ and SFout ⁻¹ may be calculated sequentially, but if a predetermined value (for example, about 1 to 1.5) is set for each of the safety factors SFin and SFout, the reciprocal numbers are set. May be.
Woutbl = Winlmt × τin (3)
Winbl = Wout ^* / τout (4)

In block B4 and block B7 of FIG. 6, the differential thrust calculation means 138, for example, the secondary shift difference thrust ΔWout as the secondary pulley-side converted difference thrust ΔWout when the target shift is realized on the secondary pulley 46 side, and the primary A primary shift difference thrust ΔWin is calculated as a differential thrust ΔW converted to the primary pulley when the target shift is realized on the pulley 42 side. Specifically, the differential thrust calculation means 138 has a relationship as shown in FIG. 11B, for example, which has been experimentally obtained and stored in advance between the secondary shift speed (dXout / dNelmout) and the secondary shift difference thrust ΔWout ( From the differential thrust map), the secondary shift differential thrust ΔWout is calculated based on the sequentially calculated secondary target shift speed (dXout / dNelmout) ^* . In addition, the differential thrust calculation means 138 has a relationship (difference thrust map) as shown in FIG. 11A, for example, which has been experimentally obtained and stored in advance between the primary shift speed (dXin / dNelmin) and the primary shift difference thrust ΔWin. ) To calculate the primary shift difference thrust ΔWin based on the sequentially calculated primary target shift speed (dXin / dNelmin) ^* .

Here, in the calculation in the blocks B3 and B4, physical characteristic diagrams that are experimentally obtained and stored in advance, such as a thrust ratio map (see FIG. 10) and a differential thrust map (see FIG. 11), are used. Therefore, there are variations in the physical characteristics in the calculation results of the secondary balance thrust Woutbl and the secondary shift difference thrust ΔWout due to individual differences in the hydraulic control circuit 100 and the like. Therefore, when considering such variations in physical characteristics, the limit thrust calculation means 134, for example, the secondary pulley 46 side thrust (secondary balance thrust Woutbl or secondary shift difference thrust ΔWout based on the primary pulley side slip limit thrust Winlmt), for example. ) Is added to the primary pulley-side slip limit thrust Winlmt prior to the calculation of the thrust on the secondary pulley 46 side. Therefore, when considering the variation with respect to the physical characteristics, in the block B3, the steady thrust calculating means 136 adds the control margin Wmgn from the following equation (3) ′ instead of, for example, the equation (3). The secondary balance thrust Woutbl is calculated based on the primary pulley side slip limit thrust Winlmt and the thrust ratio τin.
Woutbl = (Winlmt + Wmgn) × τin (3) ′

The control margin Wmgn is, for example, a constant value (design value) that has been experimentally obtained and stored in advance. However, the transient state (during the gear ratio) is more variable than the steady state (speed ratio constant state). Since a large amount of (thrust ratio map and physical characteristic diagram of the differential thrust map) is used, it is set to a large value. Further, the variation with respect to the physical characteristics related to the above calculation includes, for example, variations in the control hydraulic pressures P _SLP and P _SLS with respect to each control current to the linear solenoid valves SLP and SLS, variations in the drive circuit that outputs the control current, and control hydraulic pressure P _SLP, is different from the actual pulley pressure Pin for P _SLS, the actual hydraulic pressure of the shift amount for the hydraulic command value of the pulley pressures, such as variations in the Pout (hydraulic variation amount, the variation of the hydraulic pressure control component). Although the hydraulic pressure variation is a relatively large value depending on the unit (hard unit such as the hydraulic control circuit 100), the variation with respect to the physical characteristics related to the calculation is an extremely small value compared to the hydraulic pressure variation. . For this reason, adding the control margin Wmgn to the primary pulley side slip limit thrust Winlmt means that the target pulley pressure can be obtained no matter how much the actual pulley pressure varies with respect to the pulley pressure hydraulic command value. Compared with adding control variation to the control, deterioration of fuel consumption is suppressed. Further, since the calculations in the blocks B6 and B7 are based on the target secondary thrust Wout ^* , here, the control margin Wmgn is not added to the target secondary thrust Wout ^* prior to the calculation.

The continuously variable transmission control means 132 is, for example, a secondary pulley side shift control thrust Woutsh obtained by adding a secondary shift difference thrust ΔWout to a secondary balance thrust Woutbl as a secondary thrust necessary for preventing belt slippage on the primary pulley 42 side. (= Woutbl + ΔWout) is calculated. In block B5 of FIG. 6, continuously variable transmission control means 132 selects the larger one of secondary pulley side slip limit thrust Woutlmt and secondary pulley side shift control thrust Woutsh as target secondary thrust Wout ^* .

The continuously variable transmission control means 132 calculates the primary pulley side shift control thrust Winsh (= Winbl + ΔWin) by adding the primary shift difference thrust ΔWin to the primary balance thrust Winbl, for example. Further, in block B8 of FIG. 6, the FB control amount calculation means 140 uses the feedback control equation obtained and stored in advance as shown in the following equation (5), for example, to set the actual gear ratio γ to the target gear ratio γ. A feedback control amount (FB control correction amount) Winfb for matching with ^* is calculated. In this equation (5), Δγ is a gear ratio deviation (= γ ^* −γ) between the target gear ratio γ ^* and the actual gear ratio γ, KP is a predetermined proportionality constant, KI is a predetermined integral constant, and KD is a predetermined speed. Differential constant. Then, the continuously variable transmission control means 132 sets, for example, a value (= Winsh + Winfb) corrected by feedback control based on the speed ratio deviation Δγ for the primary pulley side shift control thrust Winsh as the target primary thrust Win ^* .
Winfb = KP × Δγ + KI × (∫Δγdt) + KD × (dΔγ / dt) (5)

In this way, the blocks B1 to B5 function as a secondary target thrust calculation unit that sets the target secondary thrust Wout ^*, that is, the secondary target thrust calculation means 150. The blocks B6 to B8 function as a primary target thrust calculation unit that sets the target primary thrust Win ^*, that is, a primary target thrust calculation means 152.

In the block B9 and the block B10 in FIG. 6, the continuously variable transmission control means 132 converts, for example, the target thrust into the target pulley pressure. Specifically, the continuously variable transmission control means 132 sets the target secondary thrust Wout ^* and the target primary thrust Win ^* to the target secondary pressure Pout ^* (= Wout ^* /) based on the pressure receiving areas of the movable sheaves 46b and 42b. 46b) and a target primary pressure Pin ^* (= Win ^* / 42b pressure receiving area). The continuously variable transmission control unit 132 sets the target secondary pressure Pout ^* and the target primary pressure Pin ^* as the secondary command pressure Pouttgt and the primary command pressure Pintgt.

CVT control means 132, for example, so that the target primary pressure Pin ^* and the target secondary pressure Pout ^* is obtained, outputs the primary instruction pressure Pintgt and secondary instruction pressure Pouttgt as hydraulic control command signal S _CVT to the hydraulic control circuit 100 To do. The hydraulic control circuit 100, the following hydraulic pressure control command signal S _CVT, with pressure regulating the primary pressure Pin by operating the linear solenoid valve SLP, actuates the linear solenoid valve SLS pressure regulating the secondary pressure Pout by.

In addition, the continuously variable transmission control means 132 detects the secondary pressure Pout detected by the secondary pressure sensor 78 so as to compensate for the hydraulic pressure variation (variation in hydraulic control) on the secondary pulley 46 side, for example. ^The secondary command pressure Pouttgt is corrected by feedback control based on a deviation ΔPout (= Pout ^* −Pout detection value) between the detected value of the secondary pressure Pout and the target secondary pressure Pout ^* so as to coincide with ^* . In the hydraulic control circuit 100 of the present embodiment, since the hydraulic sensor is not provided on the primary pulley 42 side, the primary control is performed by the feedback control on the secondary pulley 46 side based on the deviation between the detected value of the pulley pressure and the actual value. The command pressure Pintgt cannot be corrected. However, in this embodiment, for example, a value (= Winsh + Winfb) corrected by feedback control so that the actual gear ratio γ matches the target gear ratio γ ^* in the block B8 is set as the target primary thrust Win ^* . It is possible to compensate for variations in hydraulic pressure on the primary pulley 42 side.

  FIG. 12 shows a control operation for reducing the hydraulic margin (hydraulic pressure for compensating for hydraulic pressure variation) on the primary pulley 42 side where the main control operation of the electronic control unit 50, that is, the hydraulic control accuracy is not good, is improved. And is repeatedly executed with an extremely short cycle time of about several milliseconds to several tens of milliseconds, for example.

In FIG. 12, first, in step (hereinafter, step is omitted) S10 corresponding to the limit thrust calculating means 134, the input torque T _IN of the continuously variable transmission 18 and the variable pulleys 42, 46 are calculated from, for example, the equation (1). Secondary pulley side slip limit thrust Woutlmt based on the sheave angle α, the predetermined element-pulley friction coefficient μout on the secondary pulley 46 side, and the belt engagement diameter Rin on the primary pulley 42 side that is uniquely calculated from the actual gear ratio γ. Is calculated. Next, in S20 corresponding to the limit thrust calculation means 134, for example, the input torque T _IN of the continuously variable transmission 18, the sheave angle α of the variable pulleys 42 and 46, and the predetermined element on the primary pulley 42 side from the above equation (2). The primary pulley side slip limit thrust Winlmt is calculated based on the belt engagement diameter Rin on the primary pulley 42 side that is uniquely calculated from the inter-pulley friction coefficient μin and the actual speed ratio γ. In S20, for example, when considering variation with respect to the physical characteristics, the control margin Wmgn may be added to the primary pulley side slip limit thrust Winlmt. Next, in S30 corresponding to the steady thrust calculating means 136, for example, from the thrust ratio map as shown in FIG. 10 (a), based on the target gear ratio γ ^* and the reciprocal SFin ⁻¹ of the primary-side safety factor that are sequentially calculated. A thrust ratio τin is calculated. Then, a secondary balance thrust (secondary steady thrust) Woutbl is calculated based on the primary pulley side slip limit thrust Winlmt and the thrust ratio τin from the equation (3). When the control margin Wmgn is added to the primary pulley side slip limit thrust Winlmt in S20, the secondary balance thrust Woutbl is calculated from the equation (3) ′ instead of the equation (3) in S30. The Next, in S40 corresponding to the differential thrust calculation means 138, for example, from the differential thrust map as shown in FIG. 11B, the secondary shift differential thrust ΔWout based on the secondary target shift speed (dXout / dNelmout) ^* sequentially calculated. Is calculated. Next, in S50 corresponding to the continuously variable transmission control means 132, for example, the secondary shift difference thrust ΔWout is added to the secondary balance thrust Woutbl to calculate the secondary pulley side shift control thrust Woutsh (= Woutbl + ΔWout). The larger one of the secondary pulley side slip limit thrust Woutlmt and the secondary pulley side shift control thrust Woutsh is selected as the target secondary thrust Wout ^* . Note that S10 to S50 correspond to the secondary target thrust calculation means 150.

Next, in S60 corresponding to the steady thrust calculating means 136, for example, from the thrust ratio map as shown in FIG. 10B, based on the target gear ratio γ ^* and the reciprocal SFout ⁻¹ of the secondary side safety factor that are sequentially calculated. A thrust ratio τout is calculated. Then, a primary balance thrust (primary steady thrust) Winbl is calculated from the equation (4) based on the target secondary thrust Wout ^* and the thrust ratio τout. Next, in S70 corresponding to the differential thrust calculation means 138, for example, from the differential thrust map as shown in FIG. 11A, the primary shift differential thrust ΔWin based on the primary target shift speed (dXin / dNelmin) ^* sequentially calculated. Is calculated. Next, in S80 corresponding to the FB control amount calculation means 140, a feedback control amount (FB control correction amount) Winfb is calculated based on the gear ratio deviation Δγ from, for example, a predetermined feedback control equation as shown in the equation (5). The Next, in S90 corresponding to the continuously variable transmission control means 132, for example, the primary shift difference thrust ΔWin is added to the primary balance thrust Winbl to calculate the primary pulley side shift control thrust Winsh (= Winbl + ΔWin). Then, the feedback control amount Winfb is added to the primary pulley side shift control thrust Winsh to set the target primary thrust Win ^* (= Winsh + Winfb). Note that S60 to S90 correspond to the primary target thrust calculation means 152.

Next, in S100 corresponding to the continuously variable transmission control means 132, for example, the target secondary thrust Wout ^* is converted into a target secondary pressure Pout ^* (= Wout ^* / pressure receiving area) based on the pressure receiving area of the movable sheave 46b. The target secondary pressure Pout ^* is set as the secondary command pressure Pouttgt. The secondary command pressure Pouttgt is output to the hydraulic control circuit 100 as the hydraulic pressure control command signal S _CVT, the linear solenoid valve SLS is actuated by the secondary pressure Pout is pressure regulated in accordance with the oil pressure control command signal S _CVT. At this time, for example, the secondary command pressure Pouttgt is corrected by feedback control based on the deviation ΔPout (= Pout ^* −Pout detection value) so that the detection value of the secondary pressure Pout by the secondary pressure sensor 78 matches the target secondary pressure Pout ^*. Thus, the hydraulic pressure variation on the secondary pulley 46 side is compensated.

Next, in S110 corresponding to the continuously variable transmission control means 132, for example, the target primary thrust Win ^* is converted into the target primary pressure Pin ^* (= Win ^* / pressure receiving area) based on the pressure receiving area of the movable sheave 42b. The target primary pressure Pin ^* is set as the primary command pressure Pintgt. The primary command pressure Pintgt is output to the hydraulic control circuit 100 as the hydraulic pressure control command signal S _CVT, the linear solenoid valve SLP is pressurized primary pressure Pin adjusted to be actuated in accordance with the oil pressure control command signal S _CVT. At this time, for example, in S80, 90, a value (= Winsh + Winfb) corrected by feedback control so that the actual gear ratio γ matches the target gear ratio γ ^* is set as the target primary thrust Win ^*. The hydraulic pressure variation on the pulley 42 side is compensated.

As described above, in this embodiment, the target primary thrust Win ^* and the target secondary thrust Wout ^* are set based on the primary thrust Win and the secondary thrust Wout necessary for preventing belt slippage and shifting control. Therefore, in the shift control of the continuously variable transmission 18, the slip limit thrust Wlmt, that is, the lower limit thrust Wmin (the minimum lower limit thrust Winmin and the secondary lower limit thrust Woutmin), which is the minimum thrust required in the primary pulley 42 and the secondary pulley 46, is obtained. The actual primary thrust Win and the actual secondary thrust Wout are controlled within the secured thrust range.

By the way, as a thrust range in which the actual primary thrust Win and the actual secondary thrust Wout can be controlled, it is a matter of course that the lower limit thrust Wmin is ensured. The upper limit thrust Wmax (primary upper limit thrust Winmax and secondary upper limit thrust Woutmax) that is the maximum thrust to be determined cannot be exceeded. Then, for example, at least one of the target primary thrust Win ^* and the target secondary thrust Wout ^* set in the feedforward control (FF control) is the lower limit thrust Wmin and the upper limit thrust set in the pulleys 42 and 46, respectively. If it falls outside the thrust range between Wmax (referred to as the upper and lower limit thrust range Wmin-max), the target gear ratio thrust ∆W may not be produced and the actual gear ratio γ may become difficult to approach the target gear ratio γ ^* . There is. Further, in feed-forward control, even if the actual speed ratio γ does not approach the post-shift target speed ratio γ ^* l, the transitional target speed ratio γ ^* is obtained in advance until the post-shift target speed ratio γ ^* l is reached. After the predetermined time Tff, the shift difference thrust ΔW is removed or made extremely small, so there is a possibility that the shift difference thrust ΔW is insufficient and the shift does not continue. The upper limit thrust Wmax is determined based on at least the belt durability, and the upper limit thrust that can be realized with respect to hardware factors such as belt durability in the primary pulley 42 and the secondary pulley 46, respectively. It is.

Therefore, in this embodiment, when at least one of the target primary thrust Win ^* and the target secondary thrust Wout ^* is a shift that deviates from the upper and lower limit thrust ranges Wmin-max set by the pulleys 42 and 46, respectively. Sets the target primary thrust Win ^* to one of the upper limit thrust Wmax and the lower limit thrust Wmin in the primary pulley 42 until the actual speed ratio γ approaches the predetermined speed ratio difference γsyn with respect to the post-shift target speed ratio γ ^* l. At the same time, the target secondary thrust Wout ^* is set to the other of the upper limit thrust Wmax and the lower limit thrust Wmin in the secondary pulley 46, and the shift is executed. In other words, when the gear shift is out of the upper / lower limit thrust range Wmin-max, it is realized in the current vehicle state until the actual gear ratio γ approaches the predetermined gear ratio difference γsyn with respect to the target gear ratio γ ^* l after the gear shift Shift control (referred to as maximum shift control) is executed at the maximum possible shift speed (maximum shift speed). The predetermined gear ratio difference γsyn is, for example, immediately before the actual gear ratio γ reaches the post-shift target gear ratio γ ^* l (or the actual gear ratio γ reaches the post-shift target gear ratio γ ^* l. ) The maximum shift control end determination value obtained and stored in advance for determination.

Further, the case where the shift is out of the upper / lower limit thrust range Wmin-max is a shift limit state in which the shift difference thrust ΔW cannot be produced as intended. In other words, the shift that deviates from the upper and lower limit thrust range Wmin-max is, for example, a thrust component that can be actually used as the shift difference thrust ΔW in the upper and lower limit thrust range Wmin-max to advance the shift. This is a case where the actual speed ratio γ cannot reach the post-shift target speed ratio γ ^* l with the change in speed ratio calculated on the basis of the change. In other words, when shifting is out of the upper and lower limit thrust range Wmin-max, the actual speed ratio γ is changed to the post-shift target speed ratio γ ^* l after the predetermined time Tff even with the maximum speed that can be achieved in the current vehicle state. This is a case where

Further, as described above, in the continuously variable transmission 18 of the present embodiment, for example, the V-groove width of the primary pulley 42 is downshifted by increasing the V-groove width of the primary pulley 42, while the V-groove width of the primary pulley 42 is decreased. It becomes an upshift. Therefore, when the speed of the continuously variable transmission 18 is a downshift in order to obtain the maximum shift speed, the target primary thrust Win ^* is set to the primary lower limit thrust Winmin and the target secondary thrust Wout ^* is set to the secondary upper limit thrust. When the continuously variable transmission 18 is upshifted while Woutmax is set, the target primary thrust Win ^* is set to the primary upper limit thrust Winmax and the target secondary thrust Wout ^* is set to the secondary lower limit thrust Woutmin. To do.

  More specifically, referring back to FIG. 4, the limit thrust calculation means 134 calculates the secondary pulley side slip limit thrust Woutlmt (that is, the secondary lower limit thrust Woutmin) and the primary pulley side slip limit thrust from the equations (1) and (2), for example. In addition to calculating Winlmt (that is, primary lower limit thrust Winmin), a secondary upper limit thrust Woutmax and a primary upper limit thrust Winmax are calculated. The limit thrust calculating means 134, for example, obtains a value obtained by multiplying the secondary lower limit thrust Woutmin and the primary lower limit thrust Winmin by a predetermined value, which is a predetermined value that is obtained in advance and stored, and sets the secondary upper limit thrust Woutmax and the primary upper limit thrust Winmax. Respectively. Alternatively, the limit thrust calculating means 134 calculates the upper limit thrust Wmax based on the actual speed ratio γ from the relationship (upper limit thrust map) as shown in FIG. 13, for example, obtained and stored in advance between the speed ratio γ and the upper limit thrust Wmax. It may be calculated. In the equations (1) and (2), if the friction coefficient μin on the primary pulley 42 side and the friction coefficient μout on the secondary pulley 46 side are equal, the secondary lower limit thrust Woutmin and the primary lower limit thrust Winmin are equal. In this case, the secondary upper limit thrust Woutmax is equal to the primary upper limit thrust Winmax.

The maximum reach speed ratio calculation unit, that is, the maximum reach speed ratio calculation means 142 calculates the maximum reach speed ratio γa that can be reached when the shift control is performed at the maximum speed. For example, when the maximum primary transmission ratio calculation means 142 sets the target primary thrust Win ^* and the target secondary thrust Wout ^* to one of the upper limit thrust Wmax and the lower limit thrust Wmin in order to obtain the maximum shift speed, When the actual transmission gear ratio γ is calculated, a shift difference thrust ΔW that can be used for shifting is calculated, and a shift speed (maximum shift speed) that can be realized by the shift difference thrust ΔW is calculated. Sometimes, the maximum reach speed ratio γa that can be reached after the predetermined time Tff has elapsed is calculated. Hereinafter, the calculation of the maximum attainment speed ratio γa by the maximum attainment speed ratio calculating means 142 will be described separately when the shift of the continuously variable transmission 18 is a downshift and when it is an upshift. The thrust ratio τin in the following description is calculated based on the actual speed ratio γ and the reciprocal SFin ⁻¹ of the primary safety factor from a thrust ratio map as shown in FIG. 10A, for example. τout is calculated based on the actual speed ratio γ and the reciprocal SFout ⁻¹ of the secondary-side safety factor, for example, from a thrust ratio map as shown in FIG.

Specifically, when the continuously variable transmission 18 is downshifted, the primary lower limit thrust Winmin and the secondary upper limit thrust Woutmax are set as the target primary thrust Win ^* and the target secondary thrust Wout ^* , respectively. As the shift difference thrust ΔW that can be calculated, the secondary maximum shift on the secondary pulley 46 side based on the secondary upper limit thrust Woutmax and the secondary balance thrust Woutbl (= Winmin × τin) corresponding to the primary lower limit thrust Winmin from the following equation (6): The differential thrust Woutsft is calculated. Alternatively, based on the primary balance thrust Winbl (= Woutmax / τout) corresponding to the primary lower limit thrust Winmin and the secondary upper limit thrust Woutmax as the shift difference thrust ΔW that can be used for shifting, the primary maximum shift difference on the primary pulley 42 side. The thrust Winsft (= Woutmax / τout−Winmin) may be calculated.
Woutsft = Woutmax−Winmin × τin (6)

Next, as shown in the following equation (7), the secondary maximum shift speed (dXout / dNelmout) max is calculated based on the secondary maximum shift difference thrust Woutsft, for example, from a differential thrust map (mapA) as shown in FIG. . Further, as shown in the following equation (8), the maximum axial displacement (dXout) max on the secondary pulley 46 side per unit time is calculated. When calculating the primary maximum shift difference thrust Winsft as the shift difference thrust ΔW that can be used for shifting, the primary maximum shift difference thrust Winsft is calculated in the same manner as the calculation of the maximum axial displacement (dXout) max. Based on this, the maximum axial displacement (dXin) max on the primary pulley 42 side per unit time is calculated.
(dXout / dNelmout) max = mapA (Woutsft) (7)
(dXout) max = mapA (Woutsft) × (dNelmout) (8)

Next, the maximum reached pulley position Xouta that can be reached after the elapse of a predetermined time Tff from the actual pulley position Xout on the secondary pulley 46 side is changed from the following equation (9) to the maximum axial displacement (dXout) max and the predetermined time Tff. Calculate based on Then, from the relationship (transmission ratio conversion map) (not shown) obtained and stored in advance between the pulley position Xout and the transmission ratio γ, the maximum attainment transmission ratio γa is calculated based on the maximum attainment pulley position Xouta. Needless to say, the maximum transmission speed ratio γa may be calculated based on the maximum axial displacement (dXin) max.
Xouta = Xout + (dXout) max × Tff (9)

On the other hand, when the continuously variable transmission 18 is an upshift, a shift that can be used for shifting when the primary upper limit thrust Winmax and the secondary lower limit thrust Woutmin are respectively set as the target primary thrust Win ^* and the target secondary thrust Wout ^*. Based on the primary upper limit thrust Winmax and the secondary balance lower limit thrust Woutmin (= Woutmin / τout) corresponding to the primary upper limit thrust Winmax and the secondary lower limit thrust Woutmin as the differential thrust ΔW, the primary maximum transmission differential thrust on the primary pulley 42 side. Winsft is calculated. Alternatively, the secondary maximum shift difference on the secondary pulley 46 side based on the secondary lower limit thrust Woutmin and the secondary balance thrust Woutbl (= Winmax × τin) corresponding to the primary upper limit thrust Winmax as the shift difference thrust ΔW that can be used for shifting. The thrust Woutsft (= Winmax × τin−Woutmin) may be calculated.
Winsft = Winmax−Woutmin / τout (6) ′

Next, as shown in the following equation (7) ′, for example, the primary maximum shift speed (dXin / dNelmin) max is calculated based on the primary maximum shift difference thrust Winsft from the differential thrust map (mapA) as shown in FIG. To do. Further, as shown in the following equation (8) ′, the maximum axial displacement (dXin) max on the primary pulley 42 side per unit time is calculated. When calculating the secondary maximum shift difference thrust Woutsft as the shift difference thrust ΔW that can be used for shifting, the secondary maximum shift difference thrust Woutsft is calculated in the same manner as the calculation of the maximum axial displacement (dXin) max. Based on this, the maximum axial displacement (dXout) max on the secondary pulley 46 side per unit time is calculated.
(dXin / dNelmin) max = mapA (Winsft) (7) '
(dXin) max = mapA (Winsft) × (dNelmin) (8) '

Next, the maximum reached pulley position Xina that can be reached after the elapse of a predetermined time Tff from the current actual pulley position Xin on the primary pulley 42 side is determined from the following equation (9) ′ by the maximum axial displacement (dXin) max and the predetermined time Tff. Calculate based on Then, a maximum reach speed ratio γa is calculated based on the maximum reach pulley position Xina from a not-shown relationship (speed ratio conversion map) that is obtained and stored in advance between the pulley position Xin and the speed ratio γ. Needless to say, the maximum speed change ratio γa may be calculated based on the maximum axial displacement (dXout) max.
Xina = Xin + (dXin) max × Tff (9) ′

The shift limit state determination unit, that is, the shift limit state determination means 144 sets whether or not the shift limit state is set by at least one of the target primary thrust Win ^* and the target secondary thrust Wout ^{* by} the pulleys 42 and 46, respectively. It is determined based on whether or not the shift is out of the upper and lower limit thrust range Wmin-max, that is, whether or not the shift difference thrust ΔW cannot be produced as intended. That is, the shift limit state determination means 144 shifts based on whether or not the actual speed ratio γ cannot reach the post-shift target speed ratio γ ^* l after a predetermined time Tff even if the speed change is executed at the maximum speed. It is determined whether or not it is a limit state. Specifically, the shift limit state determination means 144 determines whether or not the post-shift target gear ratio γ ^* l is greater than the maximum reach gear ratio γa when the continuously variable transmission 18 is downshifted. Based on this, it is determined whether or not it is a shift limit state. Specifically, the shift limit state determination means 144 determines whether the post-shift target gear ratio γ ^* l is smaller than the maximum reach gear ratio γa when the shift of the continuously variable transmission 18 is an upshift. Based on whether or not it is in the shift limit state, it is determined.

The continuously variable transmission control unit 132 sets the target primary thrust Win ^* as the primary when the shift limit state determination unit 144 determines that the shift limit state is in effect when the shift of the continuously variable transmission 18 is downshift. A maximum shift control means 146 is provided that sets the lower limit thrust Winmin, sets the target secondary thrust Wout ^* to the secondary upper limit thrust Woutmax, and executes shift control at the maximum shift speed. Further, the maximum shift control means 146 determines the target primary thrust Win ^* as the primary when the shift limit state determination means 144 determines that the shift limit state is in a shift limit state when the shift of the continuously variable transmission 18 is an upshift. The upper limit thrust Winmax is set, the target secondary thrust Wout ^* is set to the secondary lower limit thrust Woutmin, and the shift control is executed at the maximum shift speed.

On the other hand, if the continuously variable transmission control means 132 determines that the shift limit state determination means 144 is not in the shift limit state, the target primary thrust Win ^* and the target secondary thrust Wout ^* are both upper and lower limit thrust ranges Wmin−. Since the shift is within the max range, normal control (for example, shift control according to the control operation in the flowchart of FIG. 12) that is not the shift control based on the maximum shift speed is executed.

Further, the continuously variable transmission control means 132 is such that the actual speed ratio γ approaches within the predetermined speed ratio difference γsyn with respect to the post-shift target speed ratio γ ^* l during execution of the maximum speed control by the maximum speed control means 146. The maximum shift control by the maximum shift control means 146 is terminated when it is determined that the difference has approached within the predetermined speed ratio difference γsyn.

Here, for example, at the start of a shift in which the post-shift target gear ratio γ ^* l changes stepwise, if the deviation between the actual gear ratio γ and the post-shift target gear ratio γ ^* l is relatively large, a sudden shift occurs. If the deviation is relatively small, a slow shift is achieved. In the case of a slow shift, there is also an idea that the maximum shift control by the maximum shift control means 146 does not have to be executed because the shift is originally slow. Therefore, when determining whether the shift limit state determination unit 144 is in the shift limit state, it is further determined whether or not the deviation between the actual speed ratio γ and the post-shift target speed ratio γ ^* l exceeds a predetermined value. May be determined. Specifically, the shift limit state determination means 144 determines that the post-shift target gear ratio γ ^* l is larger than the maximum reach gear ratio γa and the post-shift gear shift when the continuously variable transmission 18 is downshifted. Based on whether or not the difference (= γ ^* l−γ) between the target speed ratio γ ^* l and the actual speed ratio γ exceeds a predetermined value (> 0), it is determined whether or not the speed limit state is reached. Specifically, the shift limit state determination means 144 determines that the post-shift target gear ratio γ ^* l is smaller than the maximum reach gear ratio γa when the shift of the continuously variable transmission 18 is an upshift, and It is determined whether or not it is a shift limit state based on whether or not the difference (= γ−γ ^* l) between the actual gear ratio γ and the post-shift target gear ratio γ ^* l exceeds a predetermined value (> 0). To do. The predetermined value (positive value) is an abrupt shift determination value that is obtained and stored in advance so as not to execute the maximum shift control by the maximum shift control means 146 during a slow shift.

FIG. 14 shows the control operation for suppressing the deterioration of the shift sustainability when the main part of the control operation of the electronic control unit 50, that is, the target thrust (Win ^* , Wout ^* ) shifts out of the upper / lower limit thrust range Wmin-max. It is a flowchart explaining the operation, and is repeatedly executed with a very short cycle time of, for example, about several milliseconds to several tens of milliseconds. FIG. 14 shows an embodiment when the continuously variable transmission 18 is downshifted.

In FIG. 14, first, in S210 corresponding to the continuously variable transmission control means 132, the target input shaft rotational speed is determined based on the actual output shaft rotational speed N _OUT and the accelerator opening Acc from a shift map as shown in FIG. N _IN ^* is set, and the post-shift target gear ratio γ ^* l (= N _IN ^* / N _OUT ) is calculated based on the target input shaft rotational speed N _IN ^* . Further, the transient target speed ratio γ ^* during the speed change is determined based on the actual speed ratio γ before the start of the speed change, the target speed ratio γ ^* 1 after the speed change, and the difference between them. Next, in S220 corresponding to the limit thrust calculation means 134, for example, the primary lower limit thrust Winmin (primary pulley side slip limit thrust Winlmt) is calculated from the equation (2), for example, and the actual speed change is performed from the upper limit thrust map as shown in FIG. A secondary upper limit thrust Woutmax is calculated based on the ratio γ. Next, in S230 corresponding to the maximum attained speed ratio calculating means 142, for example, the secondary maximum speed difference thrust Woutsft is calculated based on the secondary upper limit thrust Woutmax and the primary lower limit thrust Winmin calculated in S220 from the equation (6). As shown in the equations (7) and (8), for example, the secondary maximum shift speed (dXout / dNelmout) max is extended from the differential thrust map (mapA) as shown in FIG. 11 based on the secondary maximum shift differential thrust Woutsft. The maximum axial displacement (dXout) max on the secondary pulley 46 side is calculated, and the maximum reached pulley position Xouta is calculated based on the maximum axial displacement (dXout) max and the predetermined time Tff from the equation (9). For example, the maximum reach speed ratio γa is calculated based on the maximum reach pulley position Xouta from a not-shown speed ratio conversion map. Next, in S240 corresponding to the shift limit state determination means 144, whether or not the difference (= γ ^* l−γ) between the post-shift target gear ratio γ ^* l and the actual gear ratio γ exceeds a predetermined value (> 0). Is determined. If the determination in S240 is affirmative, in S250 corresponding to the shift limit state determination means 144, it is determined whether the post-shift target speed ratio γ ^* l is greater than the maximum reach speed ratio γa. If the determination in S250 is affirmative, the target primary thrust Win ^* is set to the primary lower limit thrust Winmin and the target secondary thrust Wout ^* is set to the secondary upper limit thrust Woutmax in S260 corresponding to the maximum shift control means 146. Thus, shift control at the maximum shift speed is executed. Next, in S270 corresponding to the continuously variable transmission control means 132, it is determined whether or not the actual speed ratio γ has come within a predetermined speed ratio difference γsyn with respect to the post-shift target speed ratio γ ^* l. If the determination in S270 is negative, the process returns to S260. If the determination is positive, in S280 corresponding to the continuously variable transmission control means 132, the shift control at the maximum shift speed is terminated. On the other hand, if the determination in S240 is negative or the determination in S250 is negative, in S290 corresponding to the continuously variable transmission control means 132, normal control other than maximum transmission control (for example, in the flowchart of FIG. 12). Shift control according to the control operation) is executed.

FIG. 15 shows a control operation for suppressing deterioration of the shift sustainability when the main part of the control operation of the electronic control unit 50, that is, the target thrust (Win ^* , Wout ^* ) is shifted from the upper / lower limit thrust range Wmin-max. It is a flowchart explaining the operation, and is repeatedly executed with a very short cycle time of, for example, about several milliseconds to several tens of milliseconds. FIG. 15 is an embodiment different from the embodiment of FIG. 14 and is an embodiment in the case where the speed of the continuously variable transmission 18 is an upshift.

15, first, in S310 which corresponds to the continuously variable transmission control means 132, for example, similarly to S210 of FIG. 14, the post-shift target speed ratio gamma ^{* l} are calculated, to the post-shift target speed ratio gamma ^{* l} Based on this, a transient target gear ratio γ ^* is determined. Next, in S320 corresponding to the limit thrust calculation means 134, the primary upper limit thrust Winmax is calculated based on the actual speed ratio γ from the upper limit thrust map as shown in FIG. 13, for example, and the secondary lower limit thrust Woutmin is calculated from the equation (1), for example. (Secondary pulley side slip limit thrust Woutlmt) is calculated. Next, in S330 corresponding to the maximum reach speed ratio calculating means 142, for example, the primary maximum speed difference thrust Winsft is calculated based on the primary upper limit thrust Winmax and the secondary lower limit thrust Woutmin calculated in S320 from the equation (6) ′. Then, as shown in the equations (7) ′ and (8) ′, for example, from the differential thrust map (mapA) as shown in FIG. 11, the primary maximum shift speed (dXin / dNelmin) based on the primary maximum shift differential thrust Winsft. Thus, the maximum axial displacement (dXin) max on the primary pulley 42 side is calculated, and the maximum reached pulley position Xina based on the maximum axial displacement (dXin) max and the predetermined time Tff from the equation (9) ′. For example, the maximum reach speed ratio γa is calculated based on the maximum reach pulley position Xina from a not-shown speed ratio conversion map. Next, in S340 corresponding to the shift limit state determination means 144, whether or not the difference (= γ−γ ^* l) between the actual gear ratio γ and the post-shift target gear ratio γ ^* l exceeds a predetermined value (> 0). Is determined. If the determination in S340 is affirmative, in S350 corresponding to the shift limit state determination means 144, it is determined whether the post-shift target speed ratio γ ^* l is smaller than the maximum reach speed ratio γa. If the determination in S350 is affirmative, the target primary thrust Win ^* is set to the primary upper limit thrust Winmax and the target secondary thrust Wout ^* is set to the secondary lower limit thrust Woutmin in S360 corresponding to the maximum shift control means 146. Thus, shift control at the maximum shift speed is executed. Next, in S370 corresponding to the continuously variable transmission control means 132, it is determined whether or not the actual transmission gear ratio γ is within a predetermined transmission gear ratio difference γsyn with respect to the post-shifting target transmission gear ratio γ ^* l. If the determination in S370 is negative, the process returns to S360. If the determination is affirmative, in S380 corresponding to the continuously variable transmission control means 132, the shift control at the maximum shift speed is terminated. On the other hand, if the determination in S340 is negative or the determination in S350 is negative, in S390 corresponding to the continuously variable transmission control means 132, normal control other than maximum transmission control (for example, in the flowchart of FIG. 12). Shift control according to the control operation) is executed.

FIG. 16 is a time chart corresponding to the embodiment of FIG. 14 and is an embodiment in the case where the target primary thrust Win ^* is lower than the primary lower limit thrust Winmin when the continuously variable transmission 18 is downshifted. In FIG. 16, in the conventional example indicated by a broken line, during the period in which the target primary thrust Win ^* is lower than the primary lower limit thrust Winmin, the actual primary thrust Win (or the indicated value of the primary thrust) is blocked by the primary lower limit thrust Winmin as intended. The primary speed difference thrust ΔWin is not produced, and the actual speed ratio γ (actual N _IN ) is made difficult to approach the transient target speed ratio γ ^* (transient target N _IN ^* ). In the FF control, even in such a state, the primary shift difference thrust ΔWin is removed according to the initial target primary thrust Win ^*, so that the shift difference thrust ΔW is insufficient and the sustainability of the shift is reduced. On the other hand, in the present embodiment indicated by the solid line, the target primary thrust Win ^* is a shift that is lower than the primary lower limit thrust Winmin, so that the actual gear ratio γ (actual N _IN ) is the target gear ratio after shift γ ^*. The target primary thrust Win ^* is set to the primary lower limit thrust Winmin and the target secondary thrust Wout ^* is set until the target speed becomes less than the predetermined gear ratio difference γsyn (predetermined rotational difference) with respect to l (target N _IN ^* after shifting). The secondary upper limit thrust Woutmax is set, and shift control at the maximum shift speed is executed. Therefore, the actual gear ratio γ (actual N _IN ) is difficult to approach the transient target gear ratio γ ^* (transient target N _IN ^* ) in the initial stage of the shift as in the conventional example, but in the subsequent FF control. Compared with the conventional example, the sustainability of the shift is improved.

As described above, according to this embodiment, at least one of the target primary thrust Win ^* and the target secondary thrust Wout ^* deviates from the upper and lower limit thrust ranges Wmin-max set by the pulleys 42 and 46, respectively. When shifting, the target primary thrust Win ^* becomes the upper limit thrust Wmax and the lower limit thrust Wmin at the primary pulley 42 until the actual speed ratio γ approaches the predetermined speed ratio difference γsyn with respect to the target speed ratio γ ^* 1 after the speed change. And the target secondary thrust Wout ^* is set to the other of the upper limit thrust Wmax and the lower limit thrust Wmin in the secondary pulley 46, and the shift is executed. Maximum shifting performance can be achieved. That is, the shift can be executed at the maximum shift speed that can be currently achieved. In addition, the shift is executed at the maximum shift speed until the actual speed ratio γ approaches the predetermined speed ratio difference γsyn with respect to the post-shift target speed ratio γ ^* l. can do. Therefore, when the target thrust (Win ^* , Wout ^* ) is a shift that deviates from the upper and lower limit thrust range Wmin-max, it is possible to suppress the deterioration of the shift sustainability.

Further, according to the present embodiment, when the shift is out of the upper and lower limit thrust range Wmin-max, the shift difference thrust ΔW can be actually used in the upper and lower limit thrust range Wmin-max in order to advance the shift. Since the actual gear ratio γ cannot reach the post-shift target gear ratio γ ^* l in the gear ratio change calculated based on the thrust component, the post-shift target gear ratio is not used in the thrust component that can be actually used. When γ ^* l cannot be reached, it is possible to suppress the deterioration of shift sustainability.

Further, according to this embodiment, when the continuously variable transmission 18 is downshifted, the target primary thrust Win ^* is set to the primary lower limit thrust Winmin and the target secondary thrust Wout ^* is set to the secondary upper limit thrust Woutmax. On the other hand, when the continuously variable transmission 18 is upshifted, the target primary thrust Win ^* is set to the primary upper limit thrust Winmax and the target secondary thrust Wout ^* is set to the secondary lower limit thrust Woutmin. The maximum speed change performance at or near the limit at which the speed change can be performed can be appropriately derived. That is, it is possible to appropriately execute the shift at the maximum shift speed that can be currently achieved.

Further, according to this embodiment, the lower limit thrust Wmin is a slip limit thrust Wlmt which is calculated based on the input torque T _IN of the actual speed ratio γ and the continuously variable transmission 18, the upper thrust Wmax at least a belt Since the upper limit thrust is determined based on the endurance, the lower limit thrust Wmin is appropriately calculated to prevent belt slipping appropriately, and the upper limit thrust Wmax is appropriately determined to ensure belt durability and the like appropriately. The

Further, according to the present embodiment, the secondary pulley side slip limit thrust Woutlmt and the secondary pulley side shift control thrust Woutsh on the secondary pulley 46 side required for the shift control calculated based on the primary pulley side slip limit thrust Winlmt. Is selected as the target secondary thrust Wout ^* , for example, on the side of the secondary pulley 46 having relatively good thrust control accuracy (hydraulic control accuracy), the necessary thrust for preventing belt slippage in the secondary pulley 46 Of course, the necessary thrust for preventing belt slippage in the primary pulley 42 having relatively poor thrust control accuracy is also secured. Further, since the thrust for preventing belt slippage is controlled on the secondary pulley 46 side with relatively good thrust control accuracy, the hydraulic pressure in the primary pulley 42 with relatively poor thrust control accuracy when setting the target secondary thrust Wout ^*. There is no need to add variations. That is, the necessary thrust for preventing belt slippage in both the variable pulleys 42 and 46 is secured on the secondary pulley 46 side without adding the hydraulic pressure variation. Therefore, it is possible to improve the fuel consumption by reducing the hydraulic margin on the primary pulley 42 side where the hydraulic control accuracy is poor. Moreover, since only the thrust control accuracy (hydraulic control accuracy) on the secondary pulley 46 side is relatively improved, an increase in cost is suppressed.

Further, according to the present embodiment, the primary pulley side shift control thrust Winsh necessary for the shift control calculated based on the target secondary thrust Wout ^* is set as the target primary thrust Win ^*. The target shift can be realized while preventing belt slippage in the primary pulley 42 without adding a hydraulic pressure variation in the relatively inferior primary pulley 42.

Further, according to the present embodiment, the thrust required for the speed change control (secondary pulley side speed change control thrust Woutsh, primary pulley side speed change control thrust Winsh) is the target speed ratio γ ^* and the target speed change speed (primary target speed change). Since the thrust is necessary for realizing the speed (dXin / dNelmin) ^* and the secondary target shift speed (dXout / dNelmout) ^* ), the thrust necessary for the shift control is appropriately calculated.

Further, according to the present embodiment, the feedback control of the primary thrust Win based on the gear ratio deviation Δγ between the target gear ratio γ ^* and the actual gear ratio γ or the deviation ΔXin between the target pulley position Xin ^* and the actual pulley position Xin. Since the target primary thrust Win ^* is corrected by the above, for example, it is possible to compensate for the hydraulic pressure variation in the primary pulley 42 with relatively poor thrust control accuracy. Accordingly, it is possible to suppress deterioration in fuel consumption due to variations in hydraulic pressure, and appropriately achieve target shift and belt slip prevention with the minimum necessary pulley thrust.

Further, according to the present embodiment, the hydraulic control circuit 100 includes the secondary pressure sensor 78 for detecting the actual secondary pressure Pout acting on the secondary pulley 46 only on the secondary pulley 46 side. Since feedback control is performed with the value set as the target secondary pressure Pout ^* corresponding to the target secondary thrust Wout ^* , for example, the thrust on the secondary pulley 46 side is accurate compared to the primary pulley 42 side where no hydraulic sensor is provided. (Pulley pressure) can be controlled.

  Further, according to the present embodiment, the predetermined thrust corresponding to the variation with respect to the physical characteristics related to the calculation of the secondary pulley 46 side thrust (secondary balance thrust Woutbl and secondary shift difference thrust ΔWout) based on the primary pulley side slip limit thrust Winlmt. (Control margin) Wmgn is added to the primary pulley side slip limit thrust Winlmt prior to the calculation of the thrust on the secondary pulley 46 side, so for example, belt slippage in the primary pulley 42 with relatively poor thrust control accuracy is reliably prevented. The necessary thrust to do this is adequately secured.

  As mentioned above, although the Example of this invention was described in detail based on drawing, this invention is applied also in another aspect.

For example, in the above-described embodiment, whether or not the target thrust (Win ^* , Wout ^* ) is shifted from the upper / lower limit thrust range Wmin-max is determined after a predetermined time Tff even if the shift is executed at the maximum shift speed. Determination was made based on whether or not the actual speed ratio γ could not reach the target speed ratio γ ^* 1 after the speed change. This can determine whether or not the target thrust (Win ^* , Wout ^* ) is shifted from the upper / lower limit thrust range Wmin-max without calculating the target primary thrust Win ^* and the target secondary thrust Wout ^*. Yes, but not necessarily. For example, it is determined whether or not the target thrust (Win ^* , Wout ^* ) itself deviates from the upper and lower limit thrust range Wmin-max during execution of normal control (for example, shift control according to the control operation in the flowchart of FIG. 12). You may make it do.

In the above-described embodiment, the actual speed ratio γ is close to the target speed ratio γ ^* l after the shift within the predetermined speed ratio difference γsyn. Not exclusively. For example, from the state where the actual gear ratio gamma and the post-shift target speed ratio gamma ^{* l} is deviated relatively large, the actual gear ratio gamma is reached in how much time is remaining in the post-shift target speed ratio gamma ^{* l} And the shift control at the maximum shift speed may be terminated when the time becomes a predetermined value or less.

  In the above-described embodiment, the shift control according to the control operation in the flowchart of FIG. 12 is exemplified as the normal control, but is not necessarily limited thereto. For example, a target gear ratio (or target input shaft rotational speed, target pulley (sheave) position, etc.) is calculated from a shift map as shown in FIG. 7, and a target belt clamping pressure is calculated from a belt clamping pressure map (not shown). The present invention can also be applied to the vehicle 10 that executes shift control for calculating the target thrust at each pulley as normal control.

In the above-described embodiment, the actual speed ratio γ is set to the post-shift target speed ratio γ ^* 1 (or the transient target speed ratio γ ^* ) in the speed change control. The gear ratio γ here agrees with, for example, the pulley position X corresponding to the gear ratio γ and the input shaft rotational speed (the rotational speed of the primary pulley 42) N _{IN and the} like. It is.

  In the above-described embodiment, the upper limit thrust Wmax is determined based on the belt durability. However, in addition to the belt durability, the upper limit thrust Wmax is determined based on hardware factors such as an oil pump capacity. Also good.

  Further, in the above-described embodiment, the secondary pulley 46 is provided with the hydraulic control circuit 100 that can control the thrust (pulley pressure) with high accuracy as compared with the primary pulley 42. For example, the hydraulic control circuit 100 may include a hydraulic pressure sensor on both the primary pulley 42 and the secondary pulley 46 side, and can control the thrust with high accuracy for both the primary pulley 42 and the secondary pulley 46. Also, the hydraulic control circuit 100 may be provided with no hydraulic sensor on either the primary pulley 42 or the secondary pulley 46 side.

  In the above-described embodiment, the torque converter 14 having the lock-up clutch 26 is used as the fluid transmission device. However, the lock-up clutch 26 is not necessarily provided, and instead of the torque converter 14, Other fluid transmission devices such as a fluid coupling (fluid coupling) having no torque amplification action may be used. Further, when the forward / reverse switching device functions as the starting mechanism, a starting mechanism such as a starting clutch is provided, or an engaging device or the like capable of connecting / disconnecting the power transmission path is provided, the fluid transmission device May not be provided.

  The above description is only an embodiment, and the present invention can be implemented in variously modified and improved forms based on the knowledge of those skilled in the art.

18: Belt type continuously variable transmission (vehicle continuously variable transmission)
42: Input side variable pulley 46: Output side variable pulley 48: Transmission belt 50: Electronic control device (control device)

Claims (6)

The input side variable pulley and the output side variable pulley have a pair of variable pulleys whose effective diameters are variable, and a transmission belt wound between the pair of variable pulleys, the input side thrust in the input side variable pulley, A control device for a continuously variable transmission for a vehicle that controls the output-side thrust in the output-side variable pulley to prevent the transmission belt from slipping and sets the actual gear ratio as a target gear ratio,
Based on the input-side thrust and output-side thrust necessary for belt slip prevention and shift control, the target thrust of each of the input-side variable pulley and the output-side variable pulley is set.
If at least one of the target thrusts is a shift that deviates from the thrust range between the lower limit thrust and the upper limit thrust that are set in the input-side variable pulley and the output-side variable pulley, The target thrust of the input side variable pulley is set to one of the upper limit thrust and the lower limit thrust of the input side variable pulley until the ratio approaches within the predetermined speed ratio difference with respect to the target speed ratio, and the output side variable pulley A control device for a continuously variable transmission for a vehicle, wherein the target thrust is set to the other of the upper limit thrust and the lower limit thrust in the output-side variable pulley, and shift is executed.   When the gear shift is out of the thrust range, the actual gear ratio is set to the target gear ratio in the gear ratio change calculated based on the thrust that can actually be used in the thrust range in order to advance the gear shift. 2. The control device for a continuously variable transmission for a vehicle according to claim 1, wherein the control device is a case where the vehicle cannot be reached. When the shift of the vehicle continuously variable transmission is downshift, the target thrust of the input-side variable pulley is set to the lower limit thrust in the input-side variable pulley, and the target thrust of the output-side variable pulley is While setting the upper limit thrust in the output variable pulley,
When the shift of the vehicle continuously variable transmission is an upshift, the target thrust of the input side variable pulley is set to the upper limit thrust of the input side variable pulley, and the target thrust of the output side variable pulley is 3. The control device for a continuously variable transmission for a vehicle according to claim 1 or 2, wherein the lower limit thrust in the output side variable pulley is set. The lower limit thrust is a slip limit thrust necessary for preventing belt slippage calculated based on an actual gear ratio and an input torque of the vehicle continuously variable transmission,
The control device for a continuously variable transmission for a vehicle according to any one of claims 1 to 3, wherein the upper limit thrust is an upper limit limit thrust determined based on at least belt durability. Necessary for shift control calculated based on the lower limit thrust on one side and the lower limit thrust on the other side as the target thrust on one side of the input side variable pulley and the output side variable pulley Select the larger of the thrust on one side and
5. The thrust on the other side required for shift control calculated based on the target thrust on the one side is set as the target thrust on the other side. The control device for a continuously variable transmission for a vehicle according to claim 1.   6. The control device for a continuously variable transmission for a vehicle according to claim 5, wherein the thrust required for the shift control is a thrust required to realize a target gear ratio and a target shift speed.

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