JP4736831B2 - Control device for continuously variable transmission for vehicle - Google Patents

Description

  The present invention relates to a control device for a continuously variable transmission for a vehicle, and more particularly to shift control of the continuously variable transmission at the time of return from reverse inhibit control.

  In a control device for a continuously variable transmission for a vehicle having a primary pulley and a secondary pulley and a belt wound around both pulleys, the operation of the forward / reverse switching device for switching forward / reverse is controlled and the continuously variable transmission of the continuously variable transmission A hydraulic circuit that controls the supply and discharge of hydraulic oil to and from the primary pulley side hydraulic cylinder (actuator) that varies the groove width of the primary pulley for changing the gear ratio, and that travels forward when the vehicle speed is higher than the predetermined vehicle speed. When the shift operation is performed from the position to the reverse travel position, the power transmission path is released, that is, the power transmission path for the reverse travel is established by switching the oil path so as to be in a neutral state where the power transmission is interrupted. A control operation for performing so-called reverse inhibit control for restricting (prohibiting) is well known.

  For example, a control device for a belt-type continuously variable transmission described in Patent Document 1 is this. In this patent document 1, a selector is provided in which a forward drive gear and a reverse drive gear can be coupled to a driven shaft. A neutral position where neither drive gear is coupled to the driven shaft, and the forward drive gear is coupled to the driven shaft. Depending on the shift lever operating position, the oil passage is selectively switched to one of a drive (forward travel) position and a reverse (reverse travel) position where the reverse drive gear is coupled to the driven shaft. The shift servo connected to the selector is operated by switching, and the hydraulic pressure acting on the oil chamber of the drive pulley for changing the gear ratio of the belt type continuously variable transmission is based on the output hydraulic pressure from the two solenoid valves. A hydraulic circuit that regulates pressure with a ratio control valve When the shift lever is operated to the operation position where the oil passage for setting the selector to the reverse position is configured, the oil passage for operating the shift servo so as to forcibly hold the selector at the neutral position is set to 2 A control operation is described that executes reverse inhibit control that is configured based on the output hydraulic pressure of two solenoid valves and does not switch the selector to the reverse position.

  In addition, the hydraulic circuit described in Patent Document 1 has two electromagnetic valves so that the vehicle can be started and run without any trouble in the event of a failure in which a command signal to the solenoid valve is interrupted or hydraulic pressure is not output from the solenoid valve. When the outputs of the valves are both turned off, the transmission gear ratio of the continuously variable transmission is maintained at a predetermined intermediate transmission gear ratio.

JP-A-8-303542

  By the way, if the vehicle speed drops below the predetermined vehicle speed during the reverse inhibit control, the power transmission path is changed from the neutral state (power transmission cut-off state) to the power transmission enabled state, and returned to normal shift control. On the other hand, when the reverse inhibit control and the maintenance of the predetermined intermediate speed ratio are executed based on the output hydraulic pressure of the dual-purpose solenoid valve as described in Patent Document 1, the reverse inhibit control is being executed. It is also conceivable to configure the hydraulic circuit so that the gear ratio of the continuously variable transmission becomes a predetermined gear ratio. In such a case, depending on the configuration of the hydraulic circuit, there is a possibility that the gear ratio becomes small during the execution of the reverse inhibit control, that is, the continuously variable transmission is upshifted.

  As a result, a sudden downshift is likely to occur at the time of return to the normal shift control, that is, the hydraulic oil is rapidly discharged from the primary pulley side hydraulic cylinder. A problem has been found that may occur.

  The present invention has been made in the background of the above circumstances, and its purpose is to provide a forward / reverse switching device having a friction engagement device for switching forward / reverse, a primary pulley, a secondary pulley, and both A continuously variable transmission having a belt wound around a pulley so that when a shift operation is performed to a reverse travel position during forward travel exceeding a predetermined vehicle speed, the power transmission path is in a power transmission cut-off state. In a control device for a continuously variable transmission for a vehicle that executes reverse inhibit control for controlling the hydraulic pressure supplied to the friction engagement device, after reverse inhibit control is canceled and the power transmission path is in a state capable of transmitting power. At the time of return to return to the shift control, the belt is prevented from being loosened and belt slippage due to it.

To achieve this object, the gist of the invention according to claim 1 is that: (a) a friction engagement device for switching forward / reverse movement to a power transmission path between a driving power source and driving wheels; Controlling hydraulic pressure supplied to the friction engagement device in a vehicle provided with a forward / reverse switching device having a continuously variable transmission having a primary pulley and a secondary pulley and a belt wound around both pulleys And a hydraulic circuit for controlling an outflow and inflow amount of hydraulic oil supplied to a primary pulley side hydraulic cylinder that varies a groove width of the primary pulley for shift control of the continuously variable transmission, and the vehicle speed is a predetermined vehicle speed. When the shift operation is performed from the forward travel position to the reverse travel position during forward travel exceeding the upper limit, the power transmission path is supplied to the friction engagement device so that the power transmission path is cut off. A control device for a continuously variable transmission for a vehicle that executes reverse inhibit control for controlling hydraulic pressure, wherein (b) the reverse inhibit control is canceled when the vehicle speed falls below the predetermined vehicle speed, and the power A return speed limiting means for limiting a speed ratio change speed of the continuously variable transmission to a predetermined value or less at the time of return to return to the shift control after the transmission path is in a power transmission enabled state.

In this way, a sudden downshift occurs at the time of returning to the shift control after the reverse inhibit control is canceled and the power transmission path is brought into the power transmission enabled state when the vehicle speed falls below the predetermined vehicle speed. There is a possibility that the belt will loosen or the belt slips due to this, but the gear ratio change speed of the continuously variable transmission is limited to a predetermined value or less by the return speed limiting means. Is prevented to prevent the belt from loosening and belt slippage due to it.

  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, the shift control eliminates a deviation between the actual rotational speed of the predetermined rotating member and the target rotational speed. As described above, the control is executed by feedback control for controlling the outflow / inflow amount of hydraulic oil supplied to the primary pulley side hydraulic cylinder, and when the hydraulic circuit controls the hydraulic pressure supplied to the friction engagement device, The hydraulic ratio between the hydraulic pressure in the primary pulley-side hydraulic cylinder and the hydraulic pressure in the secondary pulley-side hydraulic cylinder that varies the groove width of the secondary pulley is set in a predetermined relationship, from the forward travel position to the reverse travel position. Prior to the start of the feedback control, when the shift operation is performed, the power transmission path is set in a state in which power transmission is possible. Gear ratio of the transmission is intended to be a predetermined gear ratio determined in accordance with the thrust ratio corresponding to temporarily the hydraulic ratio. In this way, even when the gear ratio is relatively small during the reverse inhibit control and the upshift is performed by setting the predetermined gear ratio, it is abrupt at the time of return to return to the gear shift control. Downshifting is prevented and belt slack and belt slip due to the belt are prevented from occurring.

  According to a third aspect of the present invention, in the control device for a continuously variable transmission for a vehicle according to the second aspect, the return-time shift limiting means limits the change in the target rotational speed to limit the continuously variable shift. The speed ratio change speed of the machine is limited to a predetermined value or less. By doing so, the deviation between the actual rotational speed of the predetermined rotating member and the target rotational speed is reduced at the time of return to return to the shift control, and the change in the gear ratio of the continuously variable transmission is limited. The shift is prevented, so that the belt is prevented from loosening and the belt slip caused by the belt.

  According to a fourth aspect of the present invention, in the control device for a continuously variable transmission for a vehicle according to the second aspect, the return shift limiting means sets the upper limit of the target rotational speed to set the continuously variable transmission. The speed ratio change speed of the machine is limited to a predetermined value or less. By doing so, the deviation between the actual rotational speed of the predetermined rotating member and the target rotational speed is reduced at the time of return to return to the shift control, and the change in the gear ratio of the continuously variable transmission is limited. The shift is prevented, so that the belt is prevented from loosening and the belt slip caused by the belt.

  Preferably, in the continuously variable transmission, the primary pulley side hydraulic cylinder that changes the groove width (effective diameter) of the primary pulley is provided integrally with the primary pulley, and the hydraulic pressure of the primary pulley side hydraulic cylinder is hydraulic. As a result of being changed by the control device, the engagement diameter (effective diameter) of the belt is changed, and the gear ratio is continuously changed. Further, the secondary pulley side hydraulic cylinder that changes the groove width (effective diameter) of the secondary pulley is provided integrally with the secondary pulley, and the hydraulic pressure of the secondary pulley side hydraulic cylinder is adjusted by the hydraulic control device so that the belt does not slip. Pressed.

  Normal shift control of a continuously variable transmission, that is, shift control during normal traveling at a speed higher than the extremely low vehicle speed at which the rotation speed is difficult to detect by a rotation speed sensor, for example, obtain a target gear ratio according to a predetermined shift condition, Feedback control is performed on the hydraulic pressure of the input side hydraulic cylinder so that the actual gear ratio becomes the target gear ratio, and the target on the input side (drive source side) according to the vehicle speed, output shaft rotational speed (drive wheel side rotational speed), etc. Various modes can be adopted such as obtaining the rotation speed and feedback-controlling the oil pressure of the input side hydraulic cylinder so that the actual input shaft rotation speed becomes the target rotation speed.

  The above-mentioned predetermined speed change conditions are set by a map or an arithmetic expression using, for example, driving conditions such as a driver output request amount (acceleration request amount) such as an accelerator operation amount and a vehicle speed (corresponding to an output rotation speed) as parameters Is done.

  Hydraulic control when feedback control is not possible, such as when driving at extremely low vehicle speeds, is performed by independently controlling the hydraulic pressure of the input side hydraulic cylinder and the hydraulic pressure of the output side hydraulic cylinder, respectively, and a predetermined thrust ratio τ (= output side hydraulic cylinder) The hydraulic pressure of the input side hydraulic cylinder may be controlled such that the hydraulic pressure of the input side hydraulic cylinder is equal to the hydraulic pressure of the output side hydraulic cylinder. It has a thrust ratio control valve in which hydraulic pressure is introduced as a pilot pressure, and the oil pressure of the input side hydraulic cylinder is controlled based on the control pressure output from the thrust ratio control valve, so that a predetermined thrust ratio τ is obtained. It is desirable to configure as follows.

  Preferably, an engine that is an internal combustion engine such as a gasoline engine or a diesel engine is widely used as the driving power source. Furthermore, an electric motor or the like may be used in addition to the engine as an auxiliary driving power source. Alternatively, only an electric motor may be used as a driving power source.

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

  FIG. 1 is a skeleton diagram illustrating the configuration of a vehicle drive device 10 to which the present invention is applied. This vehicle drive device 10 is a horizontal automatic transmission, which is suitably employed in an FF (front engine / front drive) type vehicle, and includes an engine 12 as a driving power source. The output of the engine 12 composed of an internal combustion engine is the crankshaft of the engine 12, the torque converter 14 as a fluid transmission device, the forward / reverse switching device 16, the belt type continuously variable transmission (CVT) 18, the reduction gear. It is transmitted to the differential gear device 22 via the device 20 and distributed to the left and right drive wheels 24L, 24R.

  The torque converter 14 includes a pump impeller 14p connected to the crankshaft of the engine 12 and a turbine impeller 14t connected to the forward / reverse switching device 16 via a turbine shaft 34 corresponding to an output side member of the torque converter 14. And power transmission is performed via a fluid. A lockup clutch 26 is provided between the pump impeller 14p and the turbine impeller 14t, and a lockup (not shown) in the hydraulic control circuit (hydraulic circuit) 100 (see FIGS. 2 and 3) is provided. The hydraulic pressure supply to the engagement side oil chamber and the release side oil chamber is switched by a control valve (L / C control valve), etc., so that it is engaged or released. The impeller 14p and the turbine impeller 14t are integrally rotated. The pump impeller 14p has a hydraulic pressure for controlling the transmission of the continuously variable transmission 18, generating a belt clamping pressure, controlling the engagement release of the lockup clutch 26, or supplying lubricating oil to each part. Is coupled to a mechanical oil pump 28 that is generated by being driven to rotate by the engine 12.

  The forward / reverse switching device 16 is composed mainly of a forward clutch C1, a reverse brake B1, and a double pinion type planetary gear device 16p, and the turbine shaft 34 of the torque converter 14 is integrally connected to the sun gear 16s. The input shaft 36 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. And is fixed to the housing selectively. 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.

  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, whereby the turbine shaft 34 is directly connected to the input shaft 36, and the forward power The transmission path is established (achieved), and 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 36 is connected to the turbine shaft 34. 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 enters a neutral state (power transmission cut-off state) in which power transmission is cut off.

  The continuously variable transmission 18 has an input-side variable pulley (primary sheave) 42 having a variable effective diameter that is an input-side member provided on the input shaft 36, and an effective diameter that is an output-side member provided on the output shaft 44. A variable output side variable pulley (secondary sheave) 46 and a transmission belt 48 wound around the variable pulleys 42 and 46 are provided, and a frictional force between the variable pulleys 42 and 46 and the transmission belt 48 is provided. Power is transmitted via the.

The variable pulleys 42 and 46 are fixed rotation bodies 42 a and 46 a fixed to the input shaft 36 and the output shaft 44, respectively, and are not rotatable relative to the input shaft 36 and the output shaft 44 and are movable in the axial direction. The movable rotating bodies 42b and 46b provided, and an input-side hydraulic cylinder 42c and an output-side hydraulic cylinder 46c as actuators for applying a thrust that makes the V-groove width between them variable. By controlling the hydraulic pressure (shift control pressure P _RATIO ) of the side hydraulic cylinder 42 c by the hydraulic control circuit 100, the V groove width of both the variable pulleys 42, 46 is changed and the engagement diameter (effective diameter) of the transmission belt 48 is changed. The gear ratio γ (= input shaft rotational speed N _IN / output shaft rotational speed N _OUT ) is continuously changed. The hydraulic pressure of the output side hydraulic cylinder 46c (clamping pressure control pressure P _BELT ) is regulated by the hydraulic control circuit 100 so that the transmission belt 48 does not slip.

  FIG. 2 is a block diagram for explaining a main part of a control system provided in the vehicle for controlling the vehicle drive device 10 of FIG. 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. By performing signal processing, 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 are executed. This is divided into control and hydraulic control for the continuously variable transmission 18 and the lockup clutch 26.

The electronic control unit 50, representing the crankshaft rotation speed corresponding to the engine rotational speed crankshaft detected by the sensor 52 rotation angle (position) A _{CR (°)} and the rotational speed of the engine 12 (engine rotational speed) N _E Signal, a signal representing the rotational speed (turbine rotational speed) _NT of the turbine shaft 34 detected by the turbine rotational speed sensor 54, and an input that is the input rotational speed of the continuously variable transmission 18 detected by the input shaft rotational speed sensor 56. rotational speed (input shaft rotational speed) signal representing the N _iN of the shaft 36, a vehicle speed sensor (output shaft rotation speed sensor) 58 by the rotational speed (output of the output shaft 44 is the output rotational speed of the continuously variable transmission 18 detected axis rotation speed) N _OUT ie vehicle speed signal representing a vehicle speed V corresponding to the output shaft speed N _OUT, en detected by the throttle sensor 60 Intake pipe 32 throttle valve opening signal representing the throttle valve opening theta _TH of the electronic throttle valve 30 provided in (see FIG. 1) of the emission 12, the cooling water temperature T _W of the engine 12 detected by a coolant temperature sensor 62 signals representative signal representative of the oil temperature T _CVT of a hydraulic circuit of the continuously variable such as transmission 18 detected by the CVT oil temperature sensor 64, the accelerator opening is an operation amount of the accelerator pedal 68 detected by the accelerator opening sensor 66 an accelerator opening signal representative of the acc, brake operation signal indicating whether B _ON operation of the foot brake is a service brake, which is detected by a foot brake switch 70, a lever position (operation of the shift lever 74 detected by a lever position sensor 72 Position) An operation position signal representing _PSH is supplied.

Further, the electronic control device 50 receives an engine output control command signal S _E for controlling the output of the engine 12, for example, a throttle signal for driving a throttle actuator 76 for controlling the opening / closing of the electronic throttle valve 30, and a fuel injection device 78. An injection signal for controlling the amount of fuel injected from the engine, an ignition timing signal for controlling the ignition timing of the engine 12 by the ignition device 80, and the like are output. Further, the shift control command signal S _T for example a command signal for controlling the shift control pressure P _RATIO for changing the speed ratio γ of the continuously variable transmission 18, clamping force control for causing adjusting clamping pressure of the transmission belt 48 A command signal S _B, for example, a command signal for controlling the clamping pressure control pressure P _BELT , a lock-up control command signal for controlling the engagement, release, and slip amount of the lock-up clutch 26, for example, the lock in the hydraulic control circuit 100 command signal for driving the solenoid valve DS2 to adjust the torque capacity of the command signal and the lock-up clutch 26 for driving the on-off solenoid valve DSU not shown to switch the valve position of the up control valve controls the line pressure P _L A command signal for driving the linear solenoid valve SLT and the linear solenoid valve SLS is used for the hydraulic control circuit 10. Output to 0.

  The shift lever 74 is arranged, for example, in the vicinity of the driver's seat and is sequentially positioned in five lever positions “P”, “R”, “N”, “D”, and “L” (see FIG. 3). Any one of them is manually operated.

  The “P” position (range) releases the power transmission path of the vehicle drive device 10, that is, a neutral state (neutral state) where the power transmission of the vehicle drive device 10 is interrupted, and is mechanically output by the mechanical parking mechanism. The parking position (position) for preventing (locking) the rotation of 44, the “R” position is the reverse traveling position (position) for reversely rotating the output shaft 44, and the “N” position. Is a neutral position (position) for setting the neutral state in which the power transmission of the vehicle drive device 10 is interrupted, and the “D” position establishes an automatic transmission mode within a transmission range that allows the transmission of the continuously variable transmission 18. This is a forward travel position (position) that allows automatic shift control to be executed, and the “L” position is operated by a strong engine brake. An engine brake position (position). Thus, the “P” position and the “N” position are non-traveling positions that are selected when the vehicle is not traveling, and the “R” position, the “D” position, and the “L” position are when the vehicle is traveling. This is the selected driving position.

FIG. 3 shows portions of the hydraulic control circuit 100 relating to the belt clamping pressure control, the transmission gear ratio control of the continuously variable transmission 18, and the engagement hydraulic pressure control of the forward clutch C1 or the reverse brake B1 accompanying the operation of the shift lever 74. It is a principal part hydraulic circuit diagram shown. In FIG. 3, the hydraulic control circuit 100 is adjusted by a clamping pressure control valve 110 and a linear solenoid valve SLT that regulate the clamping pressure control pressure P _BELT that is the hydraulic pressure of the output hydraulic cylinder 46c so that the transmission belt 48 does not slip. A switching valve that is switched to a first position that outputs the control hydraulic pressure P _SLT as the pressurized first hydraulic pressure and a second position that outputs the output hydraulic pressure P _LM2 as the second hydraulic pressure from the line pressure modulator NO. A clutch apply control valve 112 functioning as a gear ratio, a gear ratio control valve UP114 and a gear ratio control valve DN116 that regulate the speed control pressure P _RATIO that is the hydraulic pressure of the input side hydraulic cylinder 42c so that the speed ratio γ can be continuously changed. the shift control pressure P _rATIO the hydraulic ratio of the squeezing force control pressure P _BELT (ratio) previously A thrust ratio control valve 118 having a predetermined relationship, a manual valve 120 that mechanically switches the oil path according to the operation of the shift lever 74 so that the forward clutch C1 and the reverse brake B1 are engaged or released are provided. ing.

The line pressure P _L as source pressure working oil pressure output from the mechanical oil pump 28 that is driven to rotate (see FIG. 1) (generated) by the engine 12, for example, a primary regulator valve (pressure regulating valve of the relief type ) it is adapted to be pressure adjusted to a value corresponding to the engine load and the like based on the signal pressure P _SLS from the signal pressure P _SLT or the linear solenoid valve SLS from the linear solenoid valve SLT by 124. The output oil pressure _{P LM2} is regulated on the basis by the line pressure modulator NO.2 valve 122 the line pressure _{P L} as source pressure to the signal pressure _{P SLS} from the signal pressure _{P SLT} or the linear solenoid valve SLS from the linear solenoid valve SLT It comes to be pressed. Output hydraulic pressure _{P LM3} is controlled hydraulic there used as the basic pressure of the (signal _{pressure) P SLT} and the signal pressure _{P SLS,} regulated to a constant pressure by the line pressure modulator NO.3 valve 126 to line pressure _{P L} as source pressure It comes to be pressed. Modulator pressure P _M is a used as the basic pressure of the electronic control unit 50 controls oil pressure P _DS2 is the output hydraulic pressure of the control oil pressure P _DS1 and the solenoid valve DS2 which is the output hydraulic pressure of the solenoid valve DS1 that is duty-controlled by, The output hydraulic pressure _PLM3 is adjusted to a constant pressure by the modulator valve 128 using the original pressure.

Wherein the manual valve 120, the engagement pressure _{P A} that is output from the clutch apply control valve 112 is supplied to the input port 120a. When the shift lever 74 is operated to the "D" position or "L" position, and for reverse engagement pressure P _A is supplied to the forward clutch C1 via a forward output port 120f as forward running output pressure The oil passage of the manual valve 120 is switched so that the hydraulic oil in the brake B1 is drained (discharged) to the atmospheric pressure, for example, from the reverse output port 120r through the discharge port EX, and the forward clutch C1 is engaged. The reverse brake B1 is released.

Also, operating the shift lever 74 when it is operated to the "R" position, the engagement pressure P _A is the reverse in the output port 120r are supplied to the reverse brake B1 via the and the forward clutch C1 as reverse running output pressure The oil passage of the manual valve 120 is switched so that the oil is drained (discharged) from the forward output port 120f through the discharge port EX to, for example, atmospheric pressure, the reverse brake B1 is engaged, and the forward clutch C1 is engaged. Be released.

  When the shift lever 74 is operated to the “P” position and the “N” position, the oil path from the input port 120a to the forward output port 120f and the oil path from the input port 120a to the reverse output port 120r are both And the oil passage of the manual valve 120 is switched so that the hydraulic oil in the forward clutch C1 and the reverse brake B1 is drained from the manual valve 120, and both the forward clutch C1 and the reverse brake B1 are connected. Be released.

The clutch apply control valve 112, the control hydraulic pressure _{P SLT} is supplied to the manual valve 120 as an engagement pressure _{P A} via the output port 112s from the input port 112i to and signal pressure _{P SLS} by being movable in the axial direction from the input port 112k first position constituting a first oil passage for supplying the input port 112j via an output port 112t to the line pressure modulator NO.2 valve 122 and the primary regulator valve 124 and (CONTROL position) the output hydraulic pressure _{P LM2} supplied through the output port 112t of the engagement pressure _{P a} is supplied to the manual valve 120 as a and the control pressure _{P SLT} through an output port 112s from the input port 112i to the line pressure modulator NO.2 valve 122 and the primary regulator valve 124 A spool valve element 112a positioned at a second position (NORMAL position) constituting the second oil passage, and a spring 112b as an urging means for urging the spool valve element 112a toward the second position side. And an oil chamber 112c that receives the control oil pressure _PDS1 to apply a thrust toward the first position to the spool valve element 112a, and a control oil pressure P to apply a thrust toward the first position to the spool valve element 112a. _{And a} diameter difference portion 112d for receiving _DS2 .

In the clutch apply control valve 112 configured as described above, for example, a garage shift in which the shift lever 74 is operated from the “N” position to the “D” position or the “R” position at a predetermined low vehicle speed or when the vehicle is stopped. N → D shift or N → R shift), the control oil pressure P _DS1 exceeding the predetermined pressure is supplied to the oil chamber 112c, and the control oil pressure P _DS2 exceeding the predetermined pressure is supplied to the diameter difference portion 112d. The control hydraulic pressure _PSLT is supplied to the forward clutch C1 or the reverse brake B1 via the manual valve 120 by switching to the first position shown in the right half of the line. Thereby, the engagement transient hydraulic pressure of the clutch C1 and the brake B1 at the time of the garage shift is regulated by the linear solenoid valve SLT as the first electromagnetic valve. For example, the control hydraulic pressure P _SLT is a hydraulic pressure for controlling the transient engagement state of the clutch C1 and the brake B1 in the N → D shift or the N → R shift, and the clutch C1 or the brake B1 is smoothly engaged. The pressure is regulated according to a predetermined rule so that a shock at the time of engagement is suppressed.

Further, for example, when the supply of at least one of the control hydraulic pressure _PDS1 and the control hydraulic pressure _PDS2 is stopped in the steady state in which the clutch C1 and the brake B1 are engaged after the garage shift, the left half of the center line The output hydraulic pressure _PLM2 is switched to the second position shown, and is supplied to the forward clutch C1 or the reverse brake B1 via the manual valve 120. As a result, the engagement of the clutch C1 and the brake B1 after the garage shift is held by the output hydraulic pressure _PLM2 . For example, the output hydraulic pressure P _LM2 is a predetermined hydraulic pressure for _bringing the clutch C1 and the brake B1 into a fully engaged state, and is adjusted to at least a predetermined constant pressure and a hydraulic pressure corresponding to the signal pressure P _SLT. To adjust the pressure.

Thus, the clutch apply control valve 112 controls the hydraulic oil supply passage to the clutch C1 or the brake B1 in order to control the transient engagement state of the forward clutch C1 or the reverse brake B1 during the garage shift. The second solenoid valve is connected to either the first oil passage that supplies the hydraulic pressure P _SLT and the second oil passage that supplies the output hydraulic pressure P _{LM2 in} order to bring the clutch C1 or the brake B1 into a fully engaged state in a steady state. functions as a switching valve for switching on the basis of the control oil pressure _{P DS1} and the control pressure _{P DS2} from the solenoid valve DS1 and the solenoid valve DS2 as.

In this embodiment, the output hydraulic pressure of the linear solenoid valve SLT is described in two ways, the control hydraulic pressure P _SLT and the signal pressure P _SLT , but the engagement transient hydraulic pressure at the time of the garage shift is the control hydraulic pressure P _SLT. , we used a clear distinction between pilot pressure for pressure regulating the line pressure P _L as a signal pressure P _SLT. That is, the linear solenoid valve SLT outputs the control hydraulic pressure P _SLT to control the transient engagement state of the forward clutch C1 or the reverse brake B1 when the clutch apply control valve 112 is switched to the first position. , and it outputs a signal pressure P _SLT to pressure the line pressure P _L tone when the clutch apply control valve 112 is switched to the second position. Further, the signal pressure P _SLT is a pilot pressure for pressure regulating the line pressure P _L by the primary regulator valve 124, directly supplied to the hydraulic actuator thereof engaging device for engaging the clutch C1 or the brake B1 Therefore, the hydraulic pressure is smaller than the output hydraulic pressure _PLM2 .

The speed ratio control valve UP114 is closed the suppliable and output port 114k from the input port 114i to the line pressure P _L by being movable in the axial direction to the input side variable pulley 42 via the input and output ports 114j A spool valve element 114a positioned at an upshift position and an original position where the input-side variable pulley 42 communicates with the input / output port 114k via the input / output port 114j, and the spool valve element 114a toward the original position side. A spring 114b as an urging means for _urging , an oil chamber 114c that accommodates the spring 114b and receives the control hydraulic pressure _PDS2 to _apply a thrust toward the original position to the spool valve element 114a, and the spool valve element 114a control pressure P to apply a thrust force toward the upshift position side in And an oil chamber 114d that accepts _S1.

Further, the transmission ratio control valve DN116 is provided so as to be movable in the axial direction, whereby a downshift position where the input / output port 116j communicates with the discharge port EX and an original position where the input / output port 116j communicates with the input / output port 116k. A spool valve element 116a positioned at the first position, a spring 116b as an urging means for urging the spool valve element 116a toward the original position, and a spring 116b that accommodates the spool valve element 116a in the original position side. An oil chamber 116c that receives the control hydraulic pressure _PDS1 to apply a thrust toward the engine, and an oil chamber 116d that receives the control hydraulic pressure _PDS2 to apply a thrust toward the downshift position to the spool valve element 116a. .

In the transmission ratio control valve UP114 and the transmission ratio control valve DN116 thus configured, in the closed state in which the spool valve element 114a is held in the original position in accordance with the urging force of the spring 114b as shown in the left half of the center line, The input / output port 114j and the input / output port 114k are communicated with each other, and the hydraulic oil in the input side variable pulley 42 (input side hydraulic cylinder 42c) is allowed to flow to the input / output port 116j. In the closed state in which the spool valve element 116a is held in the original position according to the urging force of the spring 116b as shown in the right half of the center line, the input / output port 116j and the input / output port 116k are communicated with each other, and the thrust ratio it is allowed that the thrust ratio control oil pressure P _tau from control valve 118 to flow to the input-output port 114k.

Further, when the control oil pressure _PDS1 is supplied to the oil chamber 114d, the spool valve element 114a is increased against the urging force of the spring 114b by a thrust according to the control oil pressure _PDS1 as shown in the right half of the center line. is moved to the shift position side, the line pressure _{P L} is supplied to the control oil pressure _{P DS1} to the corresponding flow rate at the input port output from 114i port 114j menstrual the input side hydraulic cylinder 42c, input and output ports 114k is blocked Accordingly, the flow of the hydraulic oil to the speed ratio control valve DN116 side is prevented. As a result, the shift control pressure P _RATIO is increased, the V groove width of the input side variable pulley 42 is narrowed, and the speed ratio γ is decreased, that is, the continuously variable transmission 18 is upshifted.

When the control oil pressure _PDS2 is supplied to the oil chamber 116d, the spool valve element 116a is lowered against the urging force of the spring 116b by the thrust according to the control oil pressure _PDS2 , as shown in the left half of the center line. The hydraulic fluid in the input side hydraulic cylinder 42c is discharged from the input / output port 114j through the input / output port 114k and the input / output port 116j through the input / output port 116j at a flow rate corresponding to the control hydraulic pressure _PDS2 . As a result, the transmission control pressure P _RATIO is lowered, the V groove width of the input side variable pulley 42 is increased, and the transmission ratio γ is increased, that is, the continuously variable transmission 18 is downshifted.

Thus, the control oil pressure P _DS1 is the line pressure P _L input to be output to the speed ratio control valve UP114 is supplied to the input side hydraulic cylinder 42c by the speed change control pressure P _RATIO is continuously upshift control When the hydraulic pressure _PS2 is output, the hydraulic oil in the input side hydraulic cylinder 42c is discharged from the discharge port EX, and the shift control pressure P _RATIO is continuously downshifted.

For example, as shown in FIG. 4, it is actually determined from a previously stored relationship (shift map) between the vehicle speed V and the target input shaft rotational speed N _IN ^* that is the target input rotational speed of the continuously variable transmission 18 using the accelerator opening Acc as a parameter. The target input shaft rotational speed N _IN ^* of the input shaft 36 as a predetermined rotational member set based on the vehicle state indicated by the vehicle speed V and the accelerator opening Acc and the actual input shaft rotational speed (hereinafter referred to as actual input shaft rotational speed). The speed of the continuously variable transmission 18 is changed by feedback control in accordance with their rotational speed difference (deviation) ΔN _IN (= N _IN ^* −N _IN ) so that N _IN matches the speed (N _IN ). That is, the shift control pressure P _RATIO is regulated by supplying and discharging the hydraulic oil to and from the input side hydraulic cylinder 42c, and the gear ratio γ is continuously changed by feedback control.

The shift map in FIG. 4 corresponds to the shift conditions, and the target input shaft rotational speed N _IN ^* is set such that the larger the vehicle speed V is and the larger the accelerator opening Acc is, the larger the gear ratio γ is. Further, since the vehicle speed V corresponds to the output shaft rotation speed N _OUT, which is the target value of the input shaft rotational speed N _IN target input shaft rotational speed N _IN ^* corresponds to the target speed ratio, the minimum of the continuously variable transmission 18 It is determined within the range of the gear ratio γ _MIN and the maximum gear ratio γ _MAX .

However, although it may be set a target input shaft rotational speed N _IN ^* as a target value of the input shaft rotational speed N _IN, preferably, during acceleration during running and deceleration (during coasting) and shifting transient state such as The basic target input shaft rotational speed N _INC , which is a value obtained by processing the target input shaft rotational speed N _IN ^*, is set according to the traveling state of the _vehicle , and the final input shaft rotation is based on the basic target input shaft rotational speed N _INC. A transient target input shaft rotational speed N _INT that is a target value of the speed N _IN is set. Accordingly, in this case, the rotational speed difference (deviation) ΔN _INT (= N _INT −N _IN ) of the transient target input shaft rotational speed N _INT and the actual input shaft rotational speed N _IN coincide with each other. In response to this, shifting of the continuously variable transmission 18 is executed by feedback control.

Further, the control hydraulic pressure _PDS1 is supplied to the oil chamber 116c of the transmission ratio control valve DN116, and regardless of the control hydraulic pressure _PDS2 , the transmission ratio control valve DN116 is closed to limit the downshift, while the control hydraulic pressure _{PDS2 changes} the speed. The oil ratio is supplied to the oil chamber 114c of the ratio control valve UP114, and regardless of the control oil pressure _PDS1 , the transmission ratio control valve UP114 is closed to prohibit the upshift. That is, the control when the hydraulic _{P DS1} and the control pressure _{P DS2} are not supplied together but of course, also, the speed change ratio control valve UP114 and speed ratio control valve when the control oil pressure _{P DS1} and the control pressure _{P DS2} is supplied together Each of the DNs 116 is in a closed state held in its original position. As a result, one of the solenoid valves DS1 and DS2 does not function due to a failure in the electrical system, and a sudden upshift occurs even when the control hydraulic pressure _PDS1 or the control hydraulic pressure _PDS2 continues to be output at the maximum pressure. It is possible to prevent a downshift or a belt slip due to the sudden shift.

The clamping force control valve 110, via an output port 110t to line pressure P _L by opening and closing an input port 110i from the input port 110i output side variable pulley 46 and the thrust ratio control by being movable in the axial direction valve 118 The spool valve element 110a that can supply the pinching pressure control pressure P _BELT , the spring 110b as an urging means that urges the spool valve element 110a in the valve opening direction, and the spool valve element that houses the spring 110b and accommodates the spring 110b An oil chamber 110c that receives a control hydraulic pressure P _SLS to apply thrust in the valve opening direction to 110a, and a clamping pressure control pressure P that is output from the output port 110t to apply thrust in the valve closing direction to the spool valve element 110a. and a feedback oil chamber 110d to accept the _BELT, closed side to the spool valve element 110a And an oil chamber 110e that accepts modulator pressure P _M in order to impart a thrust.

In the clamping pressure control valve 110 thus configured, by the transmission belt 48 is line pressure P _L is continuously regulated pressure control control oil pressure P _SLS so as not slip as a pilot pressure, an output port 110t Is used to output the clamping pressure control pressure P _BELT .

For example, as shown in FIG. 5, an accelerator opening degree Acc corresponding to the transmission torque is used as a parameter, and is experimentally obtained in advance so as not to cause a belt slip between the gear ratio γ and the required hydraulic pressure P _BELT ^* (corresponding to the belt clamping pressure). The holding pressure of the output side hydraulic cylinder 46c is obtained so that the necessary oil pressure P _BELT ^* determined based on the vehicle state indicated by the actual gear ratio γ and the accelerator opening Acc is obtained from the relationship (the holding pressure map) stored. The control pressure P _BELT is controlled, and the belt clamping pressure, that is, the frictional force between the variable pulleys 42 and 46 and the transmission belt 48 is increased or decreased according to the clamping pressure control pressure P _BELT .

The thrust ratio control valve 118, a thrust ratio control oil pressure P the line pressure _{P L} by opening and closing an input port 118i by being movable in the axial direction from the input port 118i via an output port 118t to the speed ratio control valve DN116 a spool valve element 118a that can supply _τ , a spring 118b as an urging means that urges the spool valve element 118a in the valve opening direction, and the spring 118b is accommodated in the valve opening direction in the valve opening direction. Feedback to accept an oil chamber 118c that accepts squeezing force control pressure P _BELT for applying thrust, the thrust ratio control oil pressure P _tau output from the output port 118t to apply a thrust force in the valve closing direction to the spool valve element 118a And an oil chamber 118d.

In the thrust ratio control valve 118 configured as described above, with the pressure receiving area of the clamping force control pressure P _BELT in the oil chamber 118c a, the pressure receiving area of the thrust ratio control oil pressure P _tau in the feedback oil chamber 118d b, the spring 118b If the force is F _S , the equilibrium state is obtained by the following equation (1).
_{P τ × b = P BELT ×} a + F S ··· (1)
Therefore, the thrust ratio control oil pressure P _tau, represented by the following formula (2), is proportional to the clamping force control pressure P _{BELT.
P τ = P BELT × (a} / b) + F S / b ··· (2)

Then, the control oil pressure _P or _DS1 and the control pressure _{P DS2} is not supplied together, or the predetermined pressure or more control pressure _{P DS1} and the predetermined pressure or more control pressure _{P DS2} is both supplied, the speed ratio control valve UP114 and the speed ratio control when the valve DN116 has both been a closed state is held in the original position, since the thrust ratio control oil pressure P _tau is supplied to the input side hydraulic cylinder 42c, the shift control pressure P _rATIO thrust ratio control oil pressure P _tau Matched with. In other words, the shift control pressure P _RATIO and clamping force control pressure thrust ratio control oil pressure P _tau i.e. P _RATIO maintain a predetermined relationship hydraulic ratio (ratio) between P _BELT is output by the thrust ratio control valve 118.

For example, since the accuracy of the vehicle speed sensor 58 is low and the detection accuracy of the vehicle speed V is inferior in a low vehicle speed state lower than a predetermined extremely low vehicle speed, the rotational speed difference (deviation) ΔN _IN (or at the time of such extremely low vehicle speed traveling or starting) Instead of feedback control of the gear ratio γ based on ΔN _INT ), for example, both the control oil pressure P _DS1 and the control oil pressure P _DS2 are not supplied, and the gear ratio control valve UP114 and the gear ratio control valve DN116 are both closed. Executes the closing control. Thus, at the time of or during starting very low vehicle speed running is supplied P _RATIO proportional to P _BELT to a constant pressure ratio between the shift control pressure P _RATIO and squeezing force control pressure P _BELT is to the input side hydraulic cylinder 42c The belt slippage of the transmission belt 48 from the time when the vehicle is stopped to the extremely low vehicle speed is prevented, and based on the predetermined relationship between the transmission control pressure P _RATIO and the clamping pressure control pressure P _BELT , in other words, the thrust ratio τ (= output-side thrust W _OUT / input-side thrust W _IN ; W _OUT is the clamping pressure control pressure P _BELT × cross-sectional area of the output-side hydraulic cylinder 46c, W _IN is the shift control pressure P _RATIO × the disconnection of the input-side hydraulic cylinder 42c On the basis of the area, the speed ratio γ of the continuously variable transmission 18 is set to a predetermined speed ratio, and good vehicle travel and vehicle start are performed (see FIG. 6). The predetermined extremely low vehicle speed is a lower limit vehicle speed at which a predetermined feedback control can be executed as a vehicle speed V at which the rotational speed of the predetermined rotating member, for example, the input shaft rotational speed _NIN cannot be detected. .

FIG. 6 shows the relationship obtained and stored in advance between the speed ratio γ and the thrust ratio τ using the vehicle speed V as a parameter, and the first term (a It is a figure which shows an example when / b) is set. The parameter of the vehicle speed V indicated by the one-dot chain line in FIG. 6 is a thrust ratio τ calculated in consideration of the centrifugal hydraulic pressure in the input side hydraulic cylinder 42c and the output side hydraulic cylinder 46c, and the intersections with the solid lines (V ₀ , V ₂₀ , In V ₅₀ ), a speed ratio γ is set as a predetermined speed ratio that can be maintained during the closing control.

FIG. 7 is a functional block diagram for explaining the main part of the control function by the electronic control unit 50. In FIG. 7, the target input rotation setting means 150 is configured to change the input shaft rotation speed N _IN based on the vehicle state indicated by the actual vehicle speed V and the accelerator opening Acc from a shift map stored in advance as shown in FIG. Set the target input shaft rotational speed N _IN ^* sequentially. Then, the target input rotation setting means 150 sets the target input shaft rotational speed N _IN ^* to the basic target input shaft rotational speed N _INC according to the traveling state such as acceleration traveling, decelerating traveling (coast traveling), or gear shifting transient. The target input shaft rotational speed N _INT , which is a transient target input shaft rotational speed relative to the basic target input shaft rotational speed N _INC , is sequentially set according to the presence or absence of the acceleration request and the running state at the time of shifting transient, etc. To do.

For example, the target input rotation setting means 150 may gradually increase toward the basic target input shaft rotation speed N _INC that is increased stepwise so as to become the target input shaft rotation speed N _IN ^* at the time of downshift transition, for example. A transient target input shaft rotational speed N _INT having a first order lag with respect to the input shaft rotational speed N _INC is set. The first order lag transient target input shaft rotational speed _NINT is experimentally determined and determined in advance so that both the shift speed and the shift shock can be suppressed. Further, the target input rotation setting means 150 is a basic target input shaft rotation speed N _INC in which a predetermined lower limit limit value (lower limit guard value) is set for the target input shaft rotation speed N _IN ^* during deceleration traveling. And the basic target input shaft rotational speed N _INC is set to the transient target input shaft rotational speed N _INT as it is. (See Figure 9)

The shift control means 152 is arranged so that the actual input shaft rotation speed N _IN matches the transient target input shaft rotation speed N _INT set by the target input rotation setting means 150, that is, the rotation speed difference (deviation) ΔN _INT (= (N _INT −N _IN ), the shift of the continuously variable transmission 18 is feedback-controlled so as to eliminate the rotational speed difference (deviation) ΔN _INT . That is, the input-side shift control command signal for controlling the shift control pressure P _RATIO of the hydraulic cylinder 42c (hydraulic pressure command) is output to S _T to the hydraulic control circuit 100 to continuously change the gear ratio gamma.

The belt clamping pressure setting means 154, for example, as shown in FIG. 5, the necessary hydraulic pressure P based on the vehicle speed indicated by the actual gear ratio γ and the accelerator opening Acc from the clamping pressure map obtained experimentally in advance and stored. Set _BELT ^* .

The belt clamping pressure control means 156 controls the clamping pressure control command signal S for controlling the clamping pressure control pressure P _BELT of the output side hydraulic cylinder 46c so that the necessary hydraulic pressure P _BELT ^* set by the belt clamping pressure setting means 154 is obtained. _B is output to the hydraulic control circuit 100 to increase or decrease the belt clamping pressure.

The hydraulic control circuit 100, together with the pressure regulating the shift control pressure P _RATIO by operating the solenoid valve DS1 and the solenoid valve DS2 so shifting of the continuously variable transmission 18 is executed in accordance with the shift control command signal S _T, the clamping by operating the linear solenoid valve SLS so the belt clamping force is increased or decreased according to the pressure control command signal S _B pressure regulating the squeezing force control pressure P _bELT.

The engine output control means 158 outputs an engine output control command signal S _E , for example, a throttle signal, an injection signal, an ignition timing signal, etc., to the throttle actuator 76, the fuel injection device 78, and the ignition device 80, respectively, for output control of the engine 12. To do. For example, the engine output control means 158, the power to control the engine torque T _E and outputs a throttle signal to the throttle actuator 76 for opening and closing the electronic throttle valve 30 such that the throttle opening theta _TH corresponding to the accelerator opening Acc It functions as a source output control means.

During the garage shift, the engagement control means 160 switches the clutch apply control valve 112 to the first position side, and applies an engagement shock to control the transitional engagement state of the forward clutch C1 or the reverse brake B1. a control command signal S _a which outputs a signal pressure P _SLS to pressure regulate the control pressure P _SLT outputs and line pressure P _L to gradually increase the engagement pressure to be suppressed to the hydraulic control circuit 100 Output. For example, the engagement control unit 160 outputs the engagement transient hydraulic command pressure pcltexc to the hydraulic control circuit 100 as a command signal SLTDUTY for duty-controlling the linear solenoid valve SLT.

The hydraulic control circuit 100, according to the control command signal S _A at the time of the garage shifting, the clutch apply control valve 112 to control the above operating is allowed by predetermined pressure solenoid valve DS1 and the solenoid valve DS2 so as to be switched to the first position side oil pressure P outputs the _DS1 and the predetermined pressure or more control pressure P _DS2, the control pressure P _SLT actuates the linear solenoid valve SLT as the forward clutch C1 or the reverse brake B1 according to a predetermined rule is engaged outputs were and actuates the linear solenoid valve SLS so as the line pressure P _L is pressure regulated according to the engine load and the like to output a signal pressure P _SLS with.

Further, the engagement control means 160 may be configured to use the forward clutch C1 or the reverse brake in a steady state such as after a garage shift, for example, after a lapse of a predetermined time from the start of the garage shift, or after the control hydraulic pressure _PSLT becomes a predetermined engagement hydraulic pressure or higher. It switches the clutch apply control valve 112 to the completely engaged state by supplying the output hydraulic pressure P _LM2 to B1 to the second position, the control command for outputting a signal pressure P _SLT to pressure the line pressure P _L tone and it outputs a signal _{S a} to the hydraulic control circuit 100. For example, the engagement control means 160 outputs the line pressure command pressure plctgt to the hydraulic control circuit 100 as a command signal SLTDUTY for duty-controlling the linear solenoid valve SLT.

The hydraulic control circuit 100, according to the control command signal S _A is the steady state, the forward solenoid valve such that the clutch C1 or the output oil pressure P _LM2 to the reverse brake B1 are completely engaged state is supplied DS1 and the solenoid valve DS2 with simultaneously switching the clutch apply control valve 112 without operating the second position side, the signal pressure P _SLT actuates the linear solenoid valve SLT as the line pressure P _L is pressure regulated in accordance with the engine load and the like Output.

Thus, the linear solenoid valve SLT outputs the control hydraulic pressure P _SLT so that the forward clutch C1 or the reverse brake B1 is engaged at the first position of the clutch apply control valve 112 during garage shift (clutch pressure). Mode). The linear solenoid valve SLT, in the second position of the clutch apply control valve 112 is in a steady state, outputs a signal pressure P _SLT as the line pressure P _L is pressure regulated (referred line pressure mode). Further, in this clutch pressure mode, the control hydraulic pressure P _DS1 exceeding the predetermined pressure and the control hydraulic pressure P _DS2 exceeding the predetermined pressure are output, so that the control hydraulic pressure P _SLT is supplied to the forward clutch C1 or the reverse brake B1. At the same time, the closing control by the thrust ratio control valve 118 is performed so that a predetermined gear ratio is obtained.

The engagement control means 160, the clutch pressure mode for outputting a control command signal S _A which switches the clutch apply control valve 112 as the time of the garage shifting to the first position, at the same time the clutch pressure mode flag Xddsclt the ON ( Switch to On). On the other hand, the engagement control means 160, the line pressure mode for outputting a control command signal S _A which switches the clutch apply control valve 112 to the second position side as shown in the steady state after a garage shift, at the same time during the clutch pressure mode flag Switch Xddsclt to OFF.

  The clutch pressure mode determination means 162 determines whether or not the clutch pressure mode flag Xddsclt is OFF.

Further, the engagement control means 160 is a so-called forward travel R shift (D → (N) in which the shift lever 74 is operated from the “D” position to the “R” position through the “N” position during the forward travel in the normal state. When →→ R shift) is performed, for example, when the shift position determination means 164 determines that the D → R shift has been performed based on the lever position P _SH , the clutch apply control valve 112 is the same as in the garage shift. It switches the to the first position side, and outputs the control command signal S _a which outputs a signal pressure P _SLS to pressure the line pressure P _L regulated to the hydraulic control circuit 100 switches the line pressure mode to the clutch pressure mode.

The shift position determining means 164, be those determined or determines the current lever position P _SH based on the basis of the lever position P _SH i.e. ON signal of the lever position P _SH, the operation history of the shift lever 74 In addition to the above-described D → R shift determination, for example, N → D shift determination, N → R shift determination, “D” range determination, “N” range determination, “R” range determination, and the like are performed.

The hydraulic control circuit 100, D → during R shift according to the control command signal S _A, the clutch apply control valve 112 is a solenoid valve DS1 and the allowed to predetermined pressure or more control actuates the solenoid valve DS2 so as to be switched to the first position side it outputs the hydraulic pressure P _DS1 and the predetermined pressure or more control pressure P _DS2, by operating the linear solenoid valve SLS so as the line pressure P _L is pressure regulated according to the engine load and the like to output a signal pressure P _SLS.

Further, the engagement control means 160, when the D → R shift in the forward running, the transient of the reverse brake B1 in the same manner as when the garage shifting when the vehicle speed V is equal to or less than the predetermined vehicle speed i.e. reverse inhibit vehicle speed V _INH engagement transient oil pressure command pressure pcltexc reverse outputs a to the hydraulic control circuit 100 (reverse running, "R" range) to determine the as a command signal SLTDUTY for outputting a control pressure P _SLT for controlling the engagement state. After the reverse is confirmed, the engagement control means 160 supplies the output hydraulic pressure _PLM2 to the reverse brake B1 to bring the clutch apply control valve 112 into the fully engaged state, as in the _normal state after the garage shift. with switching to the second position, and outputs a control command signal S _a which outputs a signal pressure P _SLT to pressure the line pressure P _L regulated to the hydraulic control circuit 100 switches the clutch pressure mode to the line pressure mode.

On the other hand, the engagement control means 160, when the D → R shift in the forward running, as the vehicle speed V is the power transmission path different from the time of the garage shifting when it exceeds the reverse inhibit vehicle speed V _INH is a neutral state At the same time, a release hydraulic pressure command pressure pclopen is output to the hydraulic pressure control circuit 100 as a command signal SLTDUTY that outputs a control hydraulic pressure P _SLT for releasing the reverse brake B1 to perform reverse inhibit control. At the same time, the engagement control means 160 switches the reverse inhibit control in-progress flag XRevinh from OFF to ON during execution of the reverse inhibit control.

The reverse brake B1 is controlled oil pressure P _SLT for the released state to a hydraulic reverse brake B1 has no engagement torque capacity, hydraulic control circuit 100 in accordance with the release oil pressure command pressure Pclopen, reverse brake The linear solenoid valve SLT is operated so that B1 is released and the control hydraulic pressure P _SLT is, for example, zero or is equivalent to the return spring of the hydraulic actuator of the reverse brake B1 so as to increase the response speed. Adjust to hydraulic pressure.

  The reverse inhibit determining means 166 determines whether or not the reverse inhibit controlling flag XRevinh is ON.

Vehicle speed determining means 168 determines whether the vehicle speed V is greater than or reverse inhibit vehicle speed V _INH is below the reverse inhibit vehicle speed V _INH, and outputs a result of the determination to the engagement control means 160. The reverse inhibit vehicle speed V _INH is a determination that is experimentally obtained and stored in advance in order to suppress, for example, a switching shock or a decrease in durability of the continuously variable transmission 18 or the like when reverse is determined during forward traveling. The vehicle speed.

In other words, engagement control means 160, when the D → R shift in the forward running, when the vehicle speed V is less than or equal to the reverse inhibit vehicle speed V _INH While engaging the reverse brake B1 in the same manner as in the garage shift, When the vehicle speed V exceeds the reverse inhibit vehicle speed _VINH , reverse inhibit control that does not engage the reverse brake B1 is executed and reverse is not established.

Reverse inhibit recovery determination unit 170 determines whether the left vehicle speed V of the shift lever 74 is "R" position while the reverse inhibit control (range) is equal to or less than the reverse inhibit vehicle speed V _INH, i.e. the reverse inhibit determination means When it is determined by 166 that the reverse inhibit control in-progress flag XRevinh is ON, it is determined by the shift position determining means 164 that it is in the “R” range, and the vehicle speed determining means 168 determines that the vehicle speed V is the reverse inhibit vehicle speed _VINH. It determines whether it is determined to be less, when it is determined that the shift lever 74 in the reverse inhibit control remains speed V "R" position is equal to or less than the reverse inhibit vehicle speed V _INH is reverse inhibit return flag Is Switch the Revinh return flag from OFF to ON.

When the reverse inhibit return determination means 170 switches the Revinh return flag to ON, the engagement control means 160 returns from reverse inhibit control, that is, reverse inhibit control is stopped and the reverse inhibit control in progress flag XRevinh is set from ON. Switching to OFF, and the engagement transient hydraulic command pressure pcltexc is supplied to the hydraulic control circuit 100 as a command signal SLTDUTY for outputting the control hydraulic pressure P _{SLT in} order to control the transient engagement state of the reverse brake B1 in the same manner as in the garage shift. Output and confirm reverse. After the reverse is confirmed, the engagement control means 160 controls the clutch apply control valve 112 to supply the output hydraulic pressure _PLM2 to the reverse brake B1 and bring it into the fully engaged state, as in the steady state after the garage shift. with switching to the second position, and outputs a control command signal S _a which outputs a signal pressure P _SLT to pressure the line pressure P _L regulated to the hydraulic control circuit 100 switches the clutch pressure mode to the line pressure mode.

  By the way, during reverse inhibit control or garage shift, the clutch apply control valve 112 is switched to the first position so that the clutch pressure mode is switched to the first position. The transmission ratio is maintained. That is, feedback control of the speed ratio γ by the speed change control means 152, which is normal speed change control when the line pressure mode is set, is not executed. Then, when the garage shift is completed after the return from the reverse inhibit control, the clutch pressure mode is terminated and the normal shift control is started.

Further, the reverse during inhibit control since it becomes deceleration, the basic target input shaft rotational speed N _INC during deceleration traveling by the target input rotation setting unit 150 is the basic target input shaft rotational speed N _INC predetermined as described above Is set to the lower limit value. At the time of returning from the reverse inhibit control target as the vehicle speed V as shown in the shift map of FIG. 4 is a gamma _MAX and near maximum speed ratio in the low vehicle speed region such that following the reverse inhibit vehicle speed V _INH Since the input shaft rotational speed N _IN ^* is set, the basic target input shaft rotational speed N _{INC that} is increased stepwise from the lower limit value is set. After the return from the reverse inhibit control until the end of the garage shift (clutch pressure mode end), the speed ratio γ is still maintained at a predetermined speed ratio. For example, the normal speed change control after the end of the garage shift is performed. In preparation for the start, the target input rotation speed setting means 150 sets the transient target input shaft rotation speed N _INT to the actual input shaft rotation speed N _IN . Thereafter, the transient target input shaft rotational speed N _INT that gradually increases toward the basic target input shaft rotational speed N _INC that is increased stepwise by the target input rotational setting means 150 in accordance with the start of the normal shift control. Is set.

Then, when normal shift control is started after reverse inhibit control, the rotational speed difference (deviation) ΔN _INT (= N _INT −N _IN ) becomes large and a sudden downshift is likely to occur, that is, the rotational speed difference ( Deviation) ΔN _INT increases in proportion to the shift flow rate, and the hydraulic oil is rapidly discharged from the primary pulley side hydraulic cylinder, which may cause belt slack and belt slippage due to it. In particular, if the predetermined gear ratio is maintained at the gear ratio γ that is on the upshift side during reverse inhibit control or closed control during garage shift, the actual input shaft rotational speed N _IN is reduced during the clutch pressure mode. During the garage shift, the transient target input shaft rotational speed N _INT also decreases accordingly, so the target input rotational speed difference ΔN _INC (= | N _INC −N _INT |) further increases, and normal shift control is performed. When started, the rotational speed difference (deviation) ΔN _INT becomes large, and the occurrence of belt slack or belt slip due to the occurrence of a sudden downshift becomes noticeable.

  Therefore, when returning to normal shift control after the reverse inhibit control is canceled and the garage shift is completed, a sudden downshift is prevented to prevent the belt from becoming loose and causing belt slippage. As described above, the return speed limiting means 172 limits the speed ratio change of the continuously variable transmission 18.

Specifically, the return speed limiting means 172 has the Revinh return flag switched from OFF to ON by the reverse inhibit return determination means 170, and the clutch pressure mode flag Xddsclt is OFF by the clutch pressure mode determination means 162. If it is determined that there is a transient target input shaft that gradually increases toward the basic target input shaft rotational speed N _INC so that the rotational speed difference (deviation) ΔN _INT is reduced when returning to the normal shift control. A command for limiting the change in the rotational speed N _INT , that is, the gradient value toward which the transient target input shaft rotational speed N _INT is directed to the basic target input shaft rotational speed N _INC (change in the transient target input shaft rotational speed N _INT per unit time) Is outputted to the target input rotation setting means 150. The target input rotation setting means 150, in accordance with a command from the return speed limiting means 172, is a transient target input shaft rotation speed N whose change is limited compared to the transient target input shaft rotation speed N _INT set when the command is not output. _INT is newly set.

In this way, the return-time shift limiting means 172 _controls the speed ratio change speed of the continuously variable transmission 18 by means of the looseness of the belt by the transient target input shaft rotational speed N _INT guard that limits the change of the transient target input shaft rotational speed N _INT. The belt is limited to a predetermined value or less for preventing the belt slip caused by the belt slippage. As the transient target input shaft rotational speed N _INT guard, it may be set the upper limit of the transient target input shaft rotational speed N _INT example in addition to restricting the change of the transient target input shaft rotational speed N _INT. For example, the upper limit value of the transient target input shaft rotational speed N _INT when heading toward the basic target input shaft rotational speed N _INC is uniformly determined as an absolute value, or is determined at a predetermined ratio with respect to the basic target input shaft rotational speed N _INC . It is determined every certain time.

The shift restriction release determining means 174 determines whether or not a predetermined release condition for releasing the restriction on the change in the gear ratio of the continuously variable transmission 18 by the return-time shift restriction means 172 is satisfied. As this predetermined release condition, for example, when the target input rotational speed difference ΔN _INC (= | N _INC −N _INT |) is equal to or smaller than the predetermined rotational difference or the vehicle speed determination means 168 causes the vehicle speed V to be the predetermined extremely low vehicle speed. For example, when it is determined that:

The predetermined rotation difference is a shift restriction release determination value obtained in advance by experiments or the like that no belt slack or belt slip due to the belt will not occur even if the transient target input shaft rotation speed N _INT guard is not set. Further, in a low vehicle speed state lower than a predetermined extremely low vehicle speed, the closing control is executed instead of the feedback control of the transmission gear ratio γ based on the rotational speed difference (deviation) ΔN _INT. Since no slip occurs, the predetermined extremely low vehicle speed is used as the shift restriction release determination value.

  The return speed limiting means 172 cancels the restriction on the change in the gear ratio of the continuously variable transmission 18 when the shift restriction release determining means 174 determines that a predetermined release condition is satisfied. As a result, the normal control other than limiting the speed ratio change of the continuously variable transmission 18 is restored.

  FIG. 8 shows the main part of the control operation of the electronic control unit 50, that is, the occurrence of belt slack and the occurrence of belt slip due to the loosening of the belt at the time of returning to the normal shift control after the garage shift is completed after returning from the reverse inhibit control. It is a flowchart explaining the control action | operation for preventing, for example, is repeatedly performed by the very short cycle time of about several msec thru | or several dozen msec. FIG. 9 is an example of the control operation shown in the flowchart of FIG. 8, and is a time chart for explaining the control operation when an upshift occurs during the closing control.

  First, in step (hereinafter, step is omitted) S1 corresponding to the reverse inhibit determination means 166, it is determined whether or not the reverse inhibit control flag XRevinh is ON. When the determination of S1 is negative, the routine returns to normal control other than the control of S2 to S6 and this routine is terminated.

Time point t ₁ in FIG. 9, the vehicle speed V at the time of D → R shift in the forward running is above the reverse inhibit vehicle speed V _INH, is switched from the line pressure mode to the clutch pressure mode, and is the power transmission path is in a neutral state indicates that the release oil pressure command pressure pclopen the reverse brake B1 as a command signal SLTDUTY for outputting a control pressure P _SLT to a released state is output to the hydraulic control circuit 100 the reverse inhibit control is started performed so that ing. At the same time, the clutch pressure mode flag Xddsclt is switched to ON, and the reverse inhibit control flag XRevinh is switched to ON. Incidentally, the command signal SLTDUTY the time point t ₁ earlier linear solenoid valve SLT is a line pressure command pressure plctgt for outputting a signal pressure P _SLT to pressure the line pressure P _L tone.

Also, during the reverse inhibit control as shown from the time point t _{1 to the} time point t ₂ , the basic target input shaft rotational speed N _INC is set to the lower limit limit value of the basic target input shaft rotational speed N _INC during deceleration traveling, and The basic target input shaft rotational speed N _INC is set to the transient target input shaft rotational speed N _INT as it is. Further, since the predetermined gear ratio is maintained in the closing control, in this embodiment, the actual input shaft rotational speed _NIN is upshifted so that it gradually decreases.

In S2 corresponding to the reverse inhibit recovery judgment unit 170 if the determination in S1 is affirmative, whether it is determined to be "R" range and the vehicle speed V is equal to or less than the reverse inhibit vehicle speed V _INH Is determined. If the determination in S2 is negative, the reverse inhibit control is continued or the normal control other than the control in S3 to S6 is resumed, such as the forward clutch C1 is engaged when the "D" range is restored. This routine is terminated.

  If the determination in S2 is affirmative, in S3 corresponding to the reverse inhibit return determination means 170, the Revinh return flag, which is a reverse inhibit return flag, is switched from OFF to ON.

T ₂ time points Figure 9, while the vehicle speed V of the shift lever 74 in the reverse inhibit control is "R" range becomes less reverse inhibit vehicle speed V _INH, returns from being released reverse inhibit control or reverse inhibit control, While the reverse inhibit control flag XRevinh is switched to OFF, the Revinh return flag is switched from OFF to ON (not shown).

Then, the engagement as a command signal SLTDUTY the clutch pressure mode as shown in t ₂ time to t ₃ when it is maintained, and outputs the control pressure P _SLT for controlling the transient engagement of the reverse brake B1 The transient hydraulic command pressure pcltexc is output to the hydraulic control circuit 100 and reverse is determined. Further, at the time of returning from the reverse inhibit control target as the vehicle speed V as shown in the shift map of FIG. 4 is a gamma _MAX and near maximum speed ratio in the low vehicle speed region such that following the reverse inhibit vehicle speed V _INH Since the input shaft rotation speed N _IN ^* is set, the basic target input shaft rotation speed N _{INC that} is increased stepwise from the lower limit limit value during deceleration traveling is set. Further, until the end of the garage shift (clutch pressure mode end) when the reverse is confirmed, the closing control is continued and maintained at a predetermined gear ratio, so that the actual input shaft rotational speed _NIN further decreases. Yes. At this time, for example, the transient target input shaft rotational speed N _INT is set to the actual input shaft rotational speed N _IN in preparation for the start of normal shift control after the end of the garage shift.

  Next, in S4 corresponding to the clutch pressure mode determination means 162, it is determined whether or not the clutch pressure mode flag Xddsclt is OFF.

T ₃ time points in FIG. 9, that the reverse is to garage shift is to terminate i.e. clutch pressure mode is terminated after the confirmation to exit reverse inhibit control clutch pressure mode flag Xddsclt is switched to OFF Show.

If the determination in S4 is negative, the determination in S4 is repeatedly executed. If the determination is affirmative, in S5 corresponding to the return speed limiting means 172 and the target input rotation setting means 150, the transient target input shaft rotation. Speed change of the continuously variable transmission 18 is limited by the speed N _INT guard. For example, a change in the transient target input shaft rotational speed N _INT that gradually increases toward the basic target input shaft rotational speed N _INC is set so that the rotational speed difference (deviation) ΔN _INT is reduced at the time of return to the normal shift control. restrict command is outputted, based on the direction, the transient target input shaft rotational speed N _INT newly to the instruction has limited usually change than transient target input shaft rotational speed N _INT of which is set when no output Is set.

As the transient target input shaft rotational speed N _INT guard, an upper limit of, for example, transient target input shaft rotational speed N _INT than limiting the change in the transient target input shaft rotational speed N _INT may be set.

T ₃ after the time point of FIG. 9, in the normal speed change control feedback control of the gear ratio γ is executed, a plurality of examples of the transient target input shaft rotational speed N _INT is set in accordance with the start of the normal shift control Is shown. A solid line A is an example of a case where the gradient value toward which the transient target input shaft rotational speed N _INT is directed toward the basic target input shaft rotational speed N _INC is reduced. A solid line B is an example in a case where the upper limit value when the transient target input shaft rotational speed N _INT approaches the basic target input shaft rotational speed N _INC is uniformly determined as an absolute value. A broken line is a basic target input shaft rotational speed N _INC that is set when the speed ratio change of the continuously variable transmission 18 is not limited, and is a conventional transient target input that gradually increases toward the basic target input shaft rotational speed N _INC. It is an example of shaft rotation speed _NINT .

Thus, in the setting of the transient target input shaft rotational speed N _INT shown by the solid line A and the solid line B, the rotational speed difference (deviation) ΔN _INT (= N _INT −N _IN ) is made smaller than the setting shown by the broken line. . As a result, sudden downshifts are prevented, that is, the rotational speed difference (deviation) ΔN _INT is reduced and the shift flow rate is reduced, thereby preventing the belt from becoming loose and causing belt slippage.

Next, in S6 corresponding to the shift restriction release determination means 174, it is determined whether or not a predetermined release condition for releasing the restriction on the change in the gear ratio of the continuously variable transmission 18 executed in S5 is satisfied. Is done. For example, whether or not the target input rotational speed difference ΔN _INC (= | N _INC −N _INT |) is equal to or less than the shift restriction release determination value ΔN _inhret or whether the vehicle speed V is determined to be equal to or less than the shift restriction release determination value V _inhret. Determined.

  If the determination in S6 is negative, the processes in and after S5 are repeatedly executed. If the determination is positive, the routine returns to normal control other than limiting the speed ratio change of the continuously variable transmission 18, and the routine is terminated. .

As described above, according to the present embodiment, the reverse inhibit control is canceled when the vehicle speed V decreases to the reverse inhibit vehicle speed _VINH or less, that is, by the garage shift after the power transmission path is brought into the power transmission enabled state. After returning to the normal shift control in which the feedback control of the gear ratio γ is executed after the reverse brake B1 is engaged and reverse is determined, the rotational speed difference (deviation) ΔN _INT (= N _INT −N _IN ) is reduced so that the change in the transient target input shaft rotational speed N _INT is limited by the return speed limiting means 172 or the upper limit of the transient target input shaft rotational speed N _INT is set. Since the change in the gear ratio of 18 is limited, a sudden downshift is prevented, and the belt may be loosened or the belt may be slipped. Is prevented. In particular, even when the gear ratio γ is relatively small during the reverse inhibit control and the upshift is performed by setting the predetermined gear ratio by the closing control in the clutch pressure mode, the normal gear shift is performed. When returning to the control, a sudden downshift is prevented, and the belt is prevented from loosening and belt slippage due to the belt.

  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, the return speed limiting means 172 limits the change in the speed ratio of the continuously variable transmission 18 by the transient target input shaft rotational speed N _INT guard, but the change in the speed ratio of the continuously variable transmission 18 is limited. However, the present invention is not limited to this, and various other methods may be used. For example, instead of the transient target input shaft rotational speed N _INT guard, the flow rate of the hydraulic oil to the input side hydraulic cylinder 42c may be limited. Even in this case, a sudden downshift is prevented, and it is possible to prevent the belt from being loosened and the belt slip resulting from it from occurring.

In the above-described embodiment, the input shaft rotational speed N _IN exemplified as the rotational speed of the predetermined rotating member and the target input shaft rotational speed N _IN ^* related thereto are replaced with the input shaft rotational speed N _{IN and the} like. The engine rotational speed _NE and the related target engine rotational speed _NE ^* may be used, or the turbine rotational speed _NT and the related target turbine rotational speed _NT ^* may be used. Accordingly, a rotational speed sensor such as the input shaft rotational speed sensor 56 may be appropriately provided in accordance with the rotational speed that needs to be controlled.

  In the above-described embodiment, the torque converter 14 provided with the lock-up clutch 26 is used as the fluid transmission device. However, the lock-up clutch 26 is not necessarily provided. In addition, other fluid type power transmission devices such as a fluid coupling (fluid coupling) having no torque amplification function may be used.

  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.

1 is a skeleton diagram illustrating a vehicle drive device to which the present invention is applied. It is a block diagram explaining the principal part of the control system provided in the vehicle in order to control the vehicle drive device etc. of FIG. FIG. 4 is a main part hydraulic circuit diagram showing a part related to belt clamping pressure control of a continuously variable transmission, gear ratio control, and engagement hydraulic control of a forward clutch or a reverse brake accompanying operation of a shift lever in the hydraulic control circuit. It is a figure which shows an example of the shift map used when calculating | requiring a target input rotational speed in the shift control of a continuously variable transmission. It is a figure which shows an example of the required hydraulic pressure map which calculates | requires required hydraulic pressure according to gear ratio etc. in the clamping pressure control of a continuously variable transmission. This is a relationship obtained and stored in advance between the gear ratio and the thrust ratio with the vehicle speed as a parameter. It is a functional block diagram explaining the principal part of the control function of the electronic control apparatus of FIG. 2 prevents the loosening of the belt and the occurrence of belt slippage due to the main part of the control operation of the electronic control unit of FIG. 2, that is, at the time of return after returning from reverse inhibit control and returning to normal shift control. It is a flowchart explaining the control action for this. FIG. 9 is an example of a control operation shown in the flowchart of FIG. 8, and is a time chart illustrating the control operation when an upshift occurs during closing control. FIG.

Explanation of symbols

12: Engine (power source for running)
16: Forward / reverse switching device 18: Continuously variable transmission 24: Drive wheel 36: Input shaft (predetermined rotating member)
42: Variable pulley on the input side (primary pulley)
42c: Input side hydraulic cylinder (primary pulley side hydraulic cylinder)
46: Output side variable pulley (secondary pulley)
46c: Output side hydraulic cylinder (secondary pulley side hydraulic cylinder)
50: Electronic control device (control device)
100: Hydraulic control circuit (hydraulic circuit)
172: Return-time shift limiting means C1: Forward clutch (friction engagement device)
B1: Reverse brake (friction engagement device)

Claims (4)

A forward / reverse switching device having a frictional engagement device for switching forward / reverse on a power transmission path between the driving power source and the drive wheels, a primary pulley and a secondary pulley, and a belt wound around the pulleys; A primary pulley that controls a hydraulic pressure supplied to the friction engagement device and varies a groove width of the primary pulley for the shift control of the continuously variable transmission. A hydraulic circuit for controlling an outflow / inflow amount of hydraulic fluid supplied to the side hydraulic cylinder, and when the vehicle speed is shifted forward from a forward travel position to a reverse travel position during forward travel when the vehicle speed exceeds a predetermined vehicle speed, A continuously variable transmission for a vehicle that performs reverse inhibit control for controlling the hydraulic pressure supplied to the friction engagement device so that the transmission path is in a power transmission cutoff state A control unit,
The gear ratio of the continuously variable transmission at the time of returning to the shift control after the reverse inhibit control is canceled and the power transmission path is brought into a power transmittable state when the vehicle speed falls below the predetermined vehicle speed. A control device for a continuously variable transmission for a vehicle, comprising a return speed limiting means for limiting a change speed to a predetermined value or less . The shift control is executed by feedback control that controls the amount of hydraulic oil flowing out and flowing into the primary pulley-side hydraulic cylinder so as to eliminate the deviation between the actual rotational speed of the predetermined rotating member and the target rotational speed. Yes,
When the hydraulic circuit controls the hydraulic pressure supplied to the friction engagement device, the hydraulic ratio between the hydraulic pressure in the primary pulley-side hydraulic cylinder and the hydraulic pressure in the secondary pulley-side hydraulic cylinder that varies the groove width of the secondary pulley. Is a predetermined relationship,
When a shift operation is performed from the forward travel position to the reverse travel position, the speed ratio of the continuously variable transmission is temporarily set prior to the start of the feedback control until the power transmission path is brought into a power transmission enabled state. 2. The control device for a continuously variable transmission for a vehicle according to claim 1, wherein a predetermined speed ratio is determined according to a thrust ratio corresponding to the hydraulic pressure ratio.   3. The continuously variable transmission for a vehicle according to claim 2, wherein the speed change limiting means at the time of return limits the speed ratio change speed of the continuously variable transmission to a predetermined value or less by limiting a change in the target rotational speed. Control device.   3. The continuously variable transmission for a vehicle according to claim 2, wherein the return speed limiting means limits the speed ratio change speed of the continuously variable transmission to a predetermined value or less by setting an upper limit of the target rotational speed. Control device.

Images