JP2005042888A - Hydraulic control device for continuously variable transmission for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic control device for a continuously variable transmission for a vehicle in which the durability of a power transmission member of the continuously variable transmission and the deterioration of fuel consumption of the vehicle are suitably suppressed.
A prior to the expiration transition period of a predetermined time from the switching point from the neutral state to the running state, up-side electromagnetic valve via an oil passage L transient as the output pressure P _r of (speed-change solenoid valve) 88 is the control pressure By supplying the engagement pressure control valve 66, the up-side electromagnetic valve 88 is controlled exclusively to control the transient engagement pressure. Next, when a predetermined time has elapsed from the switching point from the neutral state to the traveling state, the switching valve (switching valve device) 68 causes the engagement pressure P _C1 of the forward clutch (hydraulic friction engagement device) C1 to be changed to the transient engagement pressure P. together it is switched to the original pressure P _C which is provided in advance from _CT, up-side electromagnetic valve 88 in response to the switching is switched to the input side hydraulic cylinder (shifting hydraulic cylinder) 43 to the control state.
[Selection] Figure 3

Description

  The present invention relates to a hydraulic control device for a continuously variable transmission for a vehicle, and more particularly, an automatic transmission mode in which a gear ratio is continuously changed according to a driving state, and a manual transmission in which a gear is changed stepwise according to a driver's up / down operation. The present invention relates to an improvement of a transmission control device having a mode.

  A hydraulic friction engagement device that is engaged to establish a power transmission path when the vehicle travels, and a continuously variable transmission that is disposed in the power transmission path and continuously changes a gear ratio. Transient engagement pressure control for controlling a transient engagement pressure of the hydraulic frictional engagement device according to a signal pressure when the hydraulic frictional engagement device is engaged for switching from a neutral state to a traveling state in a vehicle There is known a hydraulic control device for a continuously variable transmission for a vehicle including a valve and a clamping pressure control electromagnetic valve for controlling a clamping pressure control pressure for changing a clamping pressure with respect to a power transmission member of the continuously variable transmission. . For example, this is the hydraulic control device described in Patent Document 1. According to this, when the vehicle starts, the output pressure of the clamping pressure control solenoid valve is used as the signal pressure of the engagement pressure control valve, so that the start from the neutral control or the N → D operation of the shift lever by a garage shift or the like. In some cases, the hydraulic friction engagement device is smoothly engaged to reduce the engagement shock, and there is an advantage that a dedicated electromagnetic valve for controlling the transient engagement pressure is not required.

JP 2002-181175 A

  By the way, in the conventional hydraulic control device for a continuously variable transmission for a vehicle, when the output pressure of the clamping pressure control electromagnetic valve is used as the signal pressure of the engagement pressure control valve when the vehicle starts, the power of the continuously variable transmission Since the clamping pressure on the transmission member becomes unnecessary and excessively large, the durability of the power transmission member such as a transmission belt and a roller is lowered, and the hydraulic pump is operated excessively, thereby deteriorating the fuel consumption of the vehicle. There was an inconvenience of doing.

  The present invention has been made against the background of the above circumstances, and its object is to provide a transient engagement pressure that smoothly engages a hydraulic friction engagement device for switching from a neutral state to a traveling state. It is an object of the present invention to provide a hydraulic control device for a continuously variable transmission for a vehicle in which the durability of the power transmission member of the continuously variable transmission and the deterioration of the fuel consumption of the vehicle due to the occurrence of

  In order to achieve this object, the gist of the invention according to claim 1 is that a hydraulic friction engagement device that is engaged to establish a power transmission path when the vehicle travels, and the power transmission path In a vehicle provided with a continuously variable transmission that is disposed and continuously changes the gear ratio, the hydraulic friction engagement device is engaged when the hydraulic friction engagement device is engaged for switching from a neutral state to a traveling state. A hydraulic pressure is supplied to a transient engagement pressure control valve that controls a transient engagement pressure of the engagement device in accordance with a signal pressure, and a transmission hydraulic cylinder that changes a transmission ratio of the continuously variable transmission, A hydraulic control device for a continuously variable transmission for a vehicle, comprising: a shift solenoid valve that is actuated to discharge hydraulic oil, wherein: (a) the output pressure of the shift solenoid valve is used as the control pressure for the transient Used for engagement pressure control valve An oil path to be fed, and (b) a switching point from the neutral state to the traveling state after a predetermined time, and the engagement pressure of the hydraulic friction engagement device is previously provided from the transient engagement pressure. And a switching valve device for switching the shift solenoid valve to a position for controlling the shift hydraulic cylinder in response to the switching.

  The gist of the invention according to claim 2 is that, in the invention according to claim 1, the transient period in which a predetermined time elapses from the switching point from the neutral state to the traveling state is the transient relation of the hydraulic friction engagement device. Transient engagement pressure control means for controlling the solenoid valve for shifting in order to generate a transient engagement pressure in which the rise of the combined pressure is smooth, and the switching after a predetermined time from the switching point from the neutral state to the traveling state And switching control means for switching the valve device.

  In this way, before the predetermined time elapses from the switching point from the neutral state to the traveling state, the transmission gear ratio is inherently a period in which the transmission gear ratio remains at the maximum value. The output pressure is supplied as a control pressure to the transient engagement pressure control valve, so that the shift solenoid valve is controlled exclusively to control the transient engagement pressure. Next, when a predetermined time has elapsed from the switching point from the neutral state to the traveling state, the switching valve device switches the engagement pressure of the hydraulic friction engagement device from the transient engagement pressure to the original pressure provided in advance. In response to the switching, the shifting solenoid valve is brought into a state in which the shifting hydraulic cylinder can be controlled, so that the gear ratio of the continuously variable transmission is controlled by the shifting solenoid valve. As a result, the durability of the power transmission member of the continuously variable transmission and the vehicle caused by the generation of a transient engagement pressure that smoothly engages the hydraulic friction engagement device for switching from the neutral state to the traveling state The deterioration of the fuel consumption is suitably suppressed.

  According to the second aspect of the present invention, before the predetermined time has elapsed from the switching point from the neutral state to the traveling state, the gear ratio is inherently a period during which the maximum value is maintained. By supplying the output pressure of the shift solenoid valve as a control pressure to the transient engagement pressure control valve, the shift engagement solenoid valve is controlled exclusively by the transient engagement pressure control means to control the transient engagement pressure. Next, when a predetermined time has elapsed from the switching point from the neutral state to the traveling state, the switching valve device is switched by the switching control means, whereby the engagement pressure of the hydraulic friction engagement device is provided in advance from the transient engagement pressure. In response to the switching, the output pressure of the shifting solenoid valve is switched to a position for controlling the shifting hydraulic cylinder, so that the gear ratio of the continuously variable transmission is controlled by the shifting solenoid valve. The

  Here, preferably, in the above invention, switching point determination means for determining whether or not the switching point is from the neutral state to the traveling state is provided. This switching point judging means is (a) when the shift lever is operated from the neutral (N) position to the driving position, that is, the drive (D) position or the reverse (R) position, and (b) on the condition that the brake is on, for example. The determination is made by detecting the time when the neutral control for releasing the hydraulic friction engagement device in the vehicle drive device and setting it to the neutral state is released by brake-off.

  Preferably, in the above-described invention, a transient period lapse determining means for determining whether or not a transition period in which a predetermined time has elapsed since the switching point from the neutral state to the traveling state has been determined has elapsed (terminated). Is provided. This transition period elapsed determination means is idling based on whether or not a preset time has elapsed since the switching point determination means determined the switching point from the neutral state to the running state, or at the N position. The end of the transition period is determined based on the decrease in the turbine rotational speed.

  Preferably, in the above invention, the continuously variable transmission is a belt type continuously variable transmission of a type that transmits power through a transmission belt wound between a pair of variable pulleys having variable effective diameters. A traction type continuously variable transmission of a type that transmits power via a roller sandwiched between a pair of cones.

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

  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, and transmits power through a fluid. Is a fluid coupling. Further, a lock-up clutch 26 is provided between the pump impeller 14p and the turbine impeller 14t so that they can be integrally connected to rotate integrally. The pump impeller 14p is provided with a mechanical oil pump 28 that generates hydraulic pressure for controlling the speed of the continuously variable transmission 18, generating belt clamping pressure, or supplying lubricating oil to each part. It has been.

  The forward / reverse switching device 16 is composed of a double pinion type planetary gear device. The turbine shaft 34 of the torque converter 14 is connected to the sun gear 16s, and the input shaft 36 of the continuously variable transmission 18 is connected to the carrier 16c. ing. During forward travel, when the forward clutch 38 disposed between the carrier 16c and the ring gear 16r is engaged, the planetary gear unit is rotated integrally, and the turbine shaft 34 is directly connected to the input shaft 36, and the forward travel is performed. The driving force in the direction is transmitted to the drive wheels 24R and 24L. During reverse travel, when the reverse brake 40 disposed between the ring gear 16r and the housing is engaged and the direct clutch 38 is released, the input shaft 36 is rotated in reverse with respect to the turbine shaft 34, The driving force in the reverse direction is transmitted to the drive wheels 24R and 24L. When both the forward clutch 38 and the reverse brake 40 are released, the power transmission between the engine 12 and the continuously variable transmission 18 is interrupted. Both the forward clutch 38 and the reverse brake 40 are hydraulic friction engagement devices. The forward clutch C1 and the reverse brake B1 are both wet multi-plate hydraulic friction engagement devices that are frictionally engaged by a hydraulic actuator.

  The continuously variable transmission 18 includes an input side variable pulley 42 with a variable V groove width provided on the input shaft 36, an output side variable pulley 46 with a variable V groove width provided on the output shaft 44, and the like. Transmission that is a power transmission member that is wound around these variable pulleys 42 and 46 and transmits power to the input-side hydraulic cylinder 43 and the output-side hydraulic cylinder 47 that change the effective diameters of the variable pulleys 42 and 46, respectively. A belt 48 is provided, and power is transmitted through a frictional force between the variable pulleys 42 and 46 and the transmission belt 48. The variable pulleys 42 and 46 are configured to include a hydraulic cylinder that changes the V groove width, and both hydraulic pulleys are controlled by the hydraulic pressure of the hydraulic cylinder of the input side variable pulley 42 being controlled by a transmission control circuit 30 described later. The width of the V-grooves 42 and 46 is changed, the engagement diameter (effective diameter) of the transmission belt 48 is changed, and the gear ratio γ (= input shaft rotational speed Nin / output shaft rotational speed Nout) is continuously changed. The hydraulic pressure of the hydraulic cylinder of the output-side variable pulley 46 is regulated in accordance with a command from the electronic control unit 50 so as to obtain a belt clamping pressure that transmits transmission torque within a range where the transmission belt 48 does not slip.

In FIG. 2, an electronic control unit 50 that functions as a CVT controller is configured to include a so-called microcomputer, and performs signal processing according to a program stored in advance in a ROM while using a temporary storage function of a RAM. It performs gear ratio control and clamping pressure control of the continuously variable transmission 18, and includes a lever position sensor 52, an accelerator operation amount sensor 54, an engine rotational speed sensor 56, an output shaft rotational speed sensor 58 that also functions as a vehicle speed sensor, and an input shaft. From the rotational speed sensor 60, the turbine rotational speed sensor 62, etc., the lever position Psh of the shift lever 64, the accelerator pedal operation amount θ _ACC , the engine rotational speed Ne, the output shaft rotational speed Nout (corresponding to the vehicle speed V), and the input shaft rotational speed, respectively. Signals representing speed Nin, turbine rotational speed Nt, etc. are supplied Further, these input signals are processed to drive and control the up-side solenoid valve 88 and the down-side solenoid valve 90 included in the speed change control valve device 82 for speed ratio control, and the pinching pressure for pinching pressure control. The linear solenoid valve 78 that controls the control valve 80 is driven and controlled. The accelerator operation amount θ _ACC corresponds to the driver's required output amount.

  The shift lever 64 is disposed beside the driver's seat, for example, and is switched by the driver. For example, the lever position Psh is a parking P position, a reverse traveling R position, and N for blocking power transmission. Position, D position where the vehicle travels forward while automatically shifting using the entire transmission region of the continuously variable transmission 18, L for forward traveling where automatic transmission is performed only in the transmission region where the high speed side transmission region where the gear ratio γ is small is limited Positions are provided in the longitudinal direction of the vehicle. Therefore, when operated from the D position to the L position, the speed change region moves stepwise from the low speed side where the gear ratio γ is large, the input shaft rotational speed Nin and the engine rotational speed Ne are increased, and a large engine braking force is generated. Can be obtained.

  3, 4, and 5 are circuit diagrams showing a main part of the hydraulic control circuit 30 provided in the control device 10, and FIG. 3 shows a circuit related to the forward / reverse switching operation. Shows a circuit related to the adjustment operation of the belt tension control pressure, and FIG. 5 shows a circuit related to the gear ratio control.

3, the transient engagement pressure P _CT whose pressure transiently regulating constant of the clutch source pressure P _C or then pressure regulated from generated so obtained line pressure P _L by the hydraulic pump 28 via the manual valve 32, Depending on the shift position of the shift lever 64, it is alternatively supplied to the forward clutch C1 or the reverse brake B1. The shift lever 64 is connected to the manual valve 32 via a cable, a link, or the like, and the valve element position of the manual valve 32 is mechanically switched according to the operation position of the shift lever 64. . For example, when the shift lever 64 is operated from the N position to the D position or the L position, in which it up initially to the forward clutch C1 was open when the transient engagement pressure P _CT transient period elapses is supplied then the clutch source pressure P _C is supplied, the shift lever 64 is operated from the N position to the R position, together with the transient engagement pressure P _CT initially to the reverse brake B1 was open until it is supplied When the transition period elapses, the clutch original pressure P _C is supplied subsequently.

Transient engagement pressure control valve 66 includes a spool 66 _a that opens and closes between the output port 66 _pout the clutch source pressure P _C outputs the input port 66 _pi and transient engagement pressure P _CT supplied, the a spring 66 _b for urging the spool valve element 66 _a in the closing direction, a feedback oil chamber 66 _c for receiving the transient engagement pressure P _CT to generate an urging force in the valve closing direction to the spool valve element 66 _a , and a control oil chamber 66 _d for receiving through an oil passage L a control signal pressure P _r of the the up side electromagnetic valve 88 Karakara output to generate an urging force in the valve opening direction to the spool valve element 66 _a , and outputs the transient engagement pressure P _CT having a magnitude corresponding to the control signal pressure P _r.

The switching valve 68 connects the output port 68 _pout to the first input port 68 _pi1 to which the clutch original pressure P _C is supplied and the output port 68 _pout to the transient engagement pressure P _CT. spring 68 but which urges the second input port 68 _pi2 spool is allowed to alternatively position and a second position for communicating the valve member 68 _a which is supplied, the spool valve element 68 _a to the first position comprising a _b, and a spool valve element 68 control oil chamber 68 for receiving the output pressure P _S of the solenoid valve 70 in order to generate a biasing force toward the second position in _{a d,} the output pressure P _S of the solenoid valve 70 Although but outputs the transition period to be supplied is switched to the second position the transient engagement pressure P _CT from the transient engagement pressure control valve 66 to the manual valve 32, the output pressure P _S of the solenoid valve 70 When it is not supplied, it is switched to the first position. Outputting a clutch source pressure P _C to the manual valve 32. The switching valve 68 is provided with a pair of on-off ports 68 _c1 and 68 _{c2 which} are communicated with each other at the first position by the spool valve element 68 _a but are blocked at the second position. It also functions as an on-off valve that opens and closes between the up-side electromagnetic valve 88 of FIG. 4 and the up-shift control valve 84 controlled thereby.

4, the hydraulic fluid pumped by the hydraulic pump 34 is pressure regulated to a line pressure P _L by a line pressure regulating valve 72 of the relief valve type, the line pressure by the clutch based on pressure control valve 74 of the pressure reducing valve type P _L Therefore, the clutch original pressure P _C lower than that is regulated. Clutch based on pressure control valve 74, to a predetermined value higher than the forward clutch P _C1 reverse brake pressure P _B1, predetermined value higher clutch source pressure P _C on the basis that the reverse brake pressure P _B1 is supplied Adjust pressure. This clutch original pressure P _C is supplied to the solenoid pressure modulator valve 76 and the linear solenoid valve 78.

The solenoid modulator valve 76 is a pressure regulating valve of the pressure reducing valve type, and outputs a constant solenoid modulator pressure P _M is lower than the clutch source pressure P _C. The solenoid modulator pressure P _M is supplied to the clamping pressure control valve 80, an up-side solenoid valve 88 and a down-side solenoid valve 90 described later. The linear solenoid valve 78 generates a hydraulic pressure signal _PSOL having a magnitude corresponding to the command value from the electronic control unit 50 and supplies the hydraulic pressure signal _PSOL to the clamping pressure control valve 80. The clamping pressure control valve 80 includes a spool valve element 80 _a that opens and closes between an input port 80 _pi to which the line pressure P _L is supplied and an output port 80 _pout that communicates with the output-side hydraulic cylinder 47, and the spool valve element 80. _a spring 80 _b for urging _a in the valve opening direction, and a control oil chamber for receiving the hydraulic signal P _SOL output from the linear solenoid valve 78 for accommodating the spring 80 _b and generating thrust in the valve opening direction 80 _c , a feedback oil chamber 80 _d for receiving the belt tension control pressure P _B output from the clamping pressure control valve 80 for generating thrust in the valve closing direction, and the solenoid for generating thrust in the valve closing direction And an oil chamber 80 _e that receives the modulator pressure P _M , and outputs a belt tension control pressure P _B based on the hydraulic signal P _SOL from the following equation. In the following equation, F is an urging force of the spring 80 _b , s ₁ is an effective pressure receiving area of the spool valve element 80 _a in the control oil chamber 80 _c , and s ₂ is an effective pressure receiving area of the spool valve element 80 _a in the feedback oil chamber 80 _d . , s ₃ is the effective pressure receiving area of the spool valve element 80 _a in the oil chamber 80 _e.

P _B = (F + P _SOL · s ₁ + P _M · s ₃ ) / s ₂

In FIG. 5, a shift control valve device 82 supplies the hydraulic oil having the line pressure P _L exclusively to the input-side hydraulic cylinder 43 and controls the hydraulic fluid flow rate to control the shift speed in the up direction. The control valve 84 and a down shift control valve 86 that controls the shift speed in the down direction by controlling the flow rate of the hydraulic oil discharged from the input side hydraulic cylinder 43. The up-shift control valve 84 is a spool valve element 84v that opens and closes between the line oil passage _L that guides the line pressure P _L and the input side hydraulic cylinder 43, and biases the spool valve element 84v in the valve closing direction. It includes a spring 84s, and a control oil chamber 84c for guiding the control signal pressure P _r output from the up-side solenoid valve 88. The down shift control valve 86 includes a spool valve element 86v that opens and closes between the drain oil passage D and the input-side hydraulic cylinder 58, a spring 86s that urges the spool valve element 86v in the valve closing direction, And a control oil chamber 86c for guiding the control pressure output from the down-side solenoid valve 90. The up-side solenoid valve 88 and the down-side solenoid valve 90 supply the control oil pressure 84c and the control oil chamber 86c with a control signal pressure that continuously changes as a result of being duty-driven by the electronic control unit 50 shown in FIG. Then, the gear ratio γ of the continuously variable transmission 12 is continuously changed to the up side and the down side. In the downshift control valve 86, a flow passage 92 having a slight flow cross-sectional area is formed between the line oil passage L and the input-side hydraulic cylinder 58 at the closed position of the spool valve element 86v. When the up-shift control valve 84 and the down-shift control valve 86 are both closed, the throttle 94, the differential pressure forming valve 96, and the flow passage from the line oil passage L are maintained in order not to change the speed ratio γ. A small amount of hydraulic oil is supplied through 92. The input-side hydraulic cylinder 43 and the output-side hydraulic cylinder 47 have hydraulic oil applied in spite of the fact that their seal members are provided on the sliding portion due to a load that is biased with respect to the rotational axis. This is because there are slight leaks.

FIG. 6 is a functional block diagram for explaining a main part of the control function of the electronic control unit 50. The speed change control means 100 is configured based on a preset relationship such that the engine 12 operates along an optimal fuel consumption rate curve or an optimal operation curve, for example, from a shift diagram in a two-dimensional coordinate system composed of a vehicle speed axis and an engine load axis. The target input shaft rotational speed Nin _M is determined based on the vehicle speed V and the engine load (throttle opening θ _TH , accelerator opening θ _AC, etc.), and the actual input shaft rotational speed Nin detected by the input shaft rotational speed sensor 60. Is automatically controlled by drivingly controlling the up-shift control valve 84 and the down-shift control valve 86 so as to match the target input shaft rotational speed Nin _M. Further, the clamping pressure change means 102 determines the target clamping pressure generation hydraulic pressure based on the engine load (throttle opening θ _TH , accelerator opening θ _AC, etc.) corresponding to the transmission torque and the gear ratio γ from the relationship stored in advance. The linear pressure control valve 80 controlled by the linear solenoid valve 78 and the control pressure _PSOL output from the linear solenoid valve 78 is driven and controlled so that the actual hydraulic pressure in the output hydraulic cylinder 47 matches the target hydraulic pressure generation hydraulic pressure. Then, the tension of the transmission belt 48, that is, the control pressure _PSOL corresponding to the transmission belt 48 is controlled to a necessary and sufficient value so that the actual power is transmitted within a range where no slip occurs.

  The switching point determination means 104 determines whether or not the vehicle drive device 10 is a switching point from the neutral state to the traveling state, for example, the shift lever 74 is moved from the neutral (N) position to the traveling position, that is, the drive (D) position or reverse. (R) Neutral control that releases the forward clutch C1 and the reverse brake B1 in the vehicle drive device 10 and makes them in a neutral state on the condition that the vehicle is operated to the position or the brake is turned on is released by the brake off or the like. Judgment based on that.

Further, the transition period determining means 106 determines whether or not the transition period starting from the switching point from the neutral state to the traveling state of the vehicle drive device 10 has passed (finished) by, for example, the switching point determining means 104. Based on whether or not the elapsed time t _E from the determination of the switching point from the neutral state to the traveling state exceeds a preset time α, or at the N position of the shift lever 74, it is idling. The end of the transition period is determined based on the decrease in the turbine rotation speed. During this transition period, the engagement of the forward clutch C1 is prevented in order to prevent a shock caused by the engagement of the hydraulic friction engagement device, that is, the forward clutch C1, for switching the vehicle drive device 10 from the neutral state to the traveling state. application pressure is a period for the transient engagement pressure P _CT gently rise.

The transient engagement pressure control means 108 drives the electromagnetic valve 70 after the transition of the vehicle drive device 10 from the neutral state to the traveling state until the transition period elapse determining means 106 determines the end of the transient period. with switching to a second position in which the switch valve 68 is the output port 68 _pout is communicated with the second input port 68 _pi2 supplied transient engagement pressure P _CT by gently by driving the up-side electromagnetic valve 88 transient engagement pressure P _CT rise to be output from the transient engagement pressure control valve 66, supplied to the forward clutch C1 via the switching valve 68 and manual valve 32. In this transition period, since the vehicle is in a starting state and is inherently maintained at the maximum gear ratio γ _max , the switching valve 68 is used between the up-side electromagnetic valve 88 and the up-shift control valve 84. The up-shift control valve 84 is shut off and maintained in a fully closed state to be inoperable and the input side hydraulic cylinder 43 is closed. Therefore, up-side electromagnetic valve 88 is exclusively used to generate the transient engagement pressure P _CT.

Switching control means 110, the the end of the transition period is the transient period of time judging means 106 is determined, a second input port of the switching valve 68, the output port 68 _pout transient engagement pressure P _CT supplied 68 _pi2 from the second position to communicate the switches its output port 68 _pout to the first position for communicating with the first input port 68 _pi1 the clutch source pressure P _C is supplied. As a result, the engagement pressure P _C1 of the forward clutch C1 is set to the clutch original pressure P _C , and at the same time, the up-side solenoid valve 88 and the up-shift control valve 84 are communicated so that the up-side solenoid valve 88 is exclusively used for the transmission ratio. Allow to operate for control.

FIG. 7 is a flowchart for explaining a main part of the control operation of the electronic control device 50. In FIG. 7, in a step (hereinafter, step is omitted) S1 corresponding to the switching point determination means 104, it is determined whether or not the shift lever 74 is operated from the neutral position to the traveling position when the vehicle is stopped. If the determination in S1 is negative, in S5 corresponding to the shift control means 100, the actual vehicle speed V and the vehicle speed V and the engine 12 are set in advance so that the engine 12 operates along the optimal fuel consumption rate curve or the optimal operation curve. The target input shaft rotational speed Nin _M is determined based on the engine load (throttle opening θ _TH , accelerator opening θ _AC, etc.), and the actual input shaft rotational speed Nin detected by the input shaft rotational speed sensor 60 is the target. By controlling the up-shift control valve 84 and the down-shift control valve 86 so as to coincide with the input shaft rotation speed Nin _M , the speed ratio γ is automatically controlled.

However, if the determination in S1 is affirmative, the in the corresponding S2 to the transient engagement pressure control section 108, the switching valve 68 by the signal pressure P _S is its output port 68 _pout transient engagement from the solenoid valve 70 with pressure P _CT is switched to the second position which is communicated with the second input port 68 _pi2 supplied by the control pressure signal P _r from the up-side electromagnetic valve 88, the transient engagement pressure P _CT gently rises The output is output from the transient engagement pressure control valve 66, which is supplied to the forward clutch C1 via the switching valve 68 and the manual valve 32. Then, the in S3 corresponding to the transient period of time judging means 106, whether exceeds a threshold α the elapsed time t _E is set in advance from being affirmative determination in S1 is determined. Initially, the determination at S3 is negative, so the transient engagement pressure control at S2 is executed.

If the determination in S3 is affirmed while the above transient engagement pressure control is being executed, the switching valve 68 causes the output port 68 _pout to be _connected to the transient engagement pressure P in S4 corresponding to the switching control means 110. from the second position for communicating with the second input port 68 _{pi2 that CT} is supplied, the output port 68 _pout clutch source pressure P _C is switched to the first position for communicating with the first input port 68 _pi1 supplied. In S5 corresponding to the shift control means 100, the target input shaft rotational speed Nin _M is determined based on the actual vehicle speed V and the engine load (throttle opening θ _TH , accelerator opening θ _AC, etc.) from a preset relationship. There are determined, so that the actual input shaft rotation speed Nin coincides with its target input shaft rotation speed Nin _M, by driving and controlling the up-shift control valve 84 and the shift-down control valve 86, the speed ratio γ automatic Controlled.

As described above, according to the present embodiment, the gear ratio is essentially set to the maximum value γ _max before the transition period of the predetermined time from the switching point from the neutral state to the traveling state of the vehicle or the vehicle drive device 10. since a period in which have arrived tension, by up-side electromagnetic valve via an oil passage L output pressure P _r of (speed-change solenoid valve) 88 is supplied to the transient engagement pressure control valve 66 as a control pressure, The up side solenoid valve 88 is controlled exclusively to control the transient engagement pressure. Next, when a predetermined time has elapsed from the switching point from the neutral state to the traveling state, the switching valve (switching valve device) 68 causes the engagement pressure P _C1 of the forward clutch (hydraulic friction engagement device) C1 to be changed to the transient engagement pressure P. together it is switched to the original pressure P _C which is provided in advance from the _CT, since up-side electromagnetic valve 88 in response to the switching is switched to the input side hydraulic cylinder (shifting hydraulic cylinder) 43 to a controllable state, the belt-type The speed ratio γ of the continuously variable transmission 18 is controlled by the up side electromagnetic valve 88. Thus, a transmission belt (power transmission member of the belt-type continuously variable transmission 18 which is caused by generating the transient engagement pressure P _CT to smoothly engage the forward clutch C1 for switching from the neutral state to the running state 48) Deterioration of 48 durability and fuel consumption of the vehicle are suitably suppressed.

Further, according to this embodiment, the engagement pressure of the forward clutch (hydraulic friction engagement device) C1 is applied during a transition period in which a predetermined time elapses from the switching point of the vehicle or the vehicle drive device 10 from the neutral state to the traveling state. up side solenoid valve to generate the transient engagement pressure P _CT rise of P _C1 is a smooth transient engagement pressure control means 108 for controlling the (speed-change solenoid valve) 88, to the running state from the neutral state Since a switching control means 110 is provided for switching a switching valve (switching valve device) 68 when a predetermined time elapses from the switching point, the gear shift is essentially performed before the predetermined time elapses from the switching point from the neutral state to the traveling state. since the ratio is a period that is arrived tension to the maximum value gamma _max, this output pressure P _r of up-side electromagnetic valve 88 through the oil passage L is supplied to the transient engagement pressure control valve 66 as a control pressure Accordingly, up-side electromagnetic valve 88 is controlled to exclusively control the transient engagement pressure P _CT by transient engagement pressure control section 108. Next, when a predetermined time has elapsed from the switching point from the neutral state to the traveling state, the switching control unit 110 switches the position of the switching valve 68 so that the forward clutch (hydraulic friction engagement device) C1 has the transient engagement pressure P _CT. together is switched to the prearranged original pressure P _C from the output pressure P _r of up-side electromagnetic valve 88 in response to the switching is switched to a position for controlling the input-side hydraulic cylinder (shifting hydraulic cylinder) 43 The speed ratio γ of the belt type continuously variable transmission 18 is controlled by the up-side electromagnetic valve 88.

  Next, another embodiment of the present invention will be described. In the following description, parts common to those in the above-described embodiment are denoted by the same reference numerals and description thereof is omitted.

FIG. 8 shows a main part of the speed change control circuit 30 of the embodiment in which the speed ratio of the belt type continuously variable transmission 18 is performed using one speed change solenoid valve 120. In FIG. 8, for example, a second switching valve 122 that is switched in conjunction with the switching valve 68 when the output pressure P _S from the electromagnetic valve 70 is applied is provided. In the second position within the transition period, the second switching valve 122 is similar to the switching state shown in the lower side of FIG. 8, and the shifting solenoid valve 120, the oil chamber 84 s of the upshift control valve 84, and the downshift control valve. 86 is blocked between the oil chamber 86c of, the closed-inclusive state of the input-side hydraulic cylinder 43 is formed, the shift solenoid valve 120 exclusively supplies the output pressure P _r of the transient engagement pressure control valve 66 navel Thus, the engagement transient pressure is controlled. However, in the first position after the transition period has elapsed, the shift solenoid valve 120 is connected to the oil chamber 84s of the upshift control valve 84 and the oil chamber 86c of the downshift control valve 86, and the solenoid modulator valve. because certain of the solenoid modulator pressure P _M from 76 is supplied to the oil chamber 86s of the oil chamber 84c and the down shift control valve 86 of the up-shift control valve 84, by increasing or decreasing the output pressure P _r from the shift solenoid valve 120 The input side hydraulic cylinder 43 is controlled, and the speed ratio γ of the belt type continuously variable transmission 18 is controlled. Also in this embodiment, the same effects as those of the above-described embodiment can be obtained.

  The preferred embodiments of the present invention have been described in detail with reference to the drawings. However, the present invention is not limited to these embodiments, and may be implemented in other modes.

  For example, the engagement transient pressure control valve 66, the switching valve 68, the up-side electromagnetic valve 88 and the like used in the above-described embodiments can be variously modified within the range having the same function. For example, the engagement transient pressure control valve 66 and the switching valve 68 may be constituted by a plurality of valves, and the up-side electromagnetic valve 88 may be constituted by being combined with the up speed change control valve 84.

  In the above-described embodiment, the forward clutch C1 is used as the hydraulic friction engagement device to explain the operation. However, the reverse brake B1 may be used instead. In this case, the engagement transition period starts from the time when the shift lever 64 is operated from the N position to the R position.

  In the above-described embodiment, as the continuously variable transmission, power is transmitted via a pair of input-side variable pulley 42 and output-side variable pulley 46 that are variable in effective diameter, and are transmitted through a transmission belt 48. The belt type continuously variable transmission 18 is used, and is interposed via a roller that is sandwiched between a pair of cones and is rotatable about an axis that intersects the rotation axis of the cone. For example, a traction type continuously variable transmission that transmits power may be used.

  In addition, although not illustrated one by one, the present invention is implemented with various modifications within a range not departing from the gist thereof.

1 is a skeleton diagram of a vehicle drive device to which a hydraulic control device of the present invention is applied. It is a block diagram explaining the control system of the continuously variable transmission in the vehicle drive device of FIG. FIG. 2 is a hydraulic control circuit provided in the vehicle drive device of FIG. 1, showing a circuit related to a forward / reverse switching operation. FIG. 2 is a hydraulic control circuit provided in the vehicle drive device of FIG. 1, showing a circuit related to a pressure adjustment operation of a belt tension control pressure. FIG. 2 is a hydraulic control circuit provided in the vehicle drive device of FIG. 1 and shows a circuit related to gear ratio control. It is a functional block diagram explaining the principal part of the control function of the electronic control apparatus of FIG. It is a flowchart explaining the principal part of the control action of the electronic controller of FIG. It is a hydraulic control circuit of the other Example of this invention, Comprising: It is a figure which shows the principal part for performing gear shifting with a single solenoid valve for gear shifting.

Explanation of symbols

18: Belt type continuously variable transmission (continuously variable transmission)
43: Input side hydraulic cylinder (speed change hydraulic cylinder)
50: Electronic control device 66: Transient engagement pressure control valve 68: Switching valve (switching valve device)
88: Up-side solenoid valve (shifting solenoid valve)
108: transient engagement pressure control means 110: switching control means 120: speed change solenoid valve L: oil passage C1: forward clutch (hydraulic friction engagement device)

Claims (2)

A hydraulic friction engagement device that is engaged to establish a power transmission path when the vehicle travels, and a continuously variable transmission that is disposed in the power transmission path and continuously changes a gear ratio. A transient engagement pressure control valve for controlling a transient engagement pressure of the hydraulic friction engagement device according to a signal pressure when the hydraulic friction engagement device is engaged for switching from a neutral state to a traveling state in a vehicle. And a shift solenoid valve that is actuated to supply hydraulic pressure to a shift hydraulic cylinder that changes the gear ratio of the continuously variable transmission or to discharge hydraulic oil in the hydraulic cylinder. A hydraulic control device for a continuously variable transmission,
An oil passage for supplying the output pressure of the shift solenoid valve as the control pressure to the transient engagement pressure control valve;
The switch is made after a predetermined time from the switching point from the neutral state to the running state, and the engagement pressure of the hydraulic friction engagement device is switched from the transient engagement pressure to a pre-set original pressure and responds to the change. And a switching valve device for switching the shift solenoid valve to a position for controlling the engagement pressure of the shift hydraulic cylinder. A hydraulic control device for a continuously variable transmission for a vehicle. During the transition period until a predetermined time elapses from the switching point from the neutral state to the traveling state, the speed change gear is generated so as to generate a transient engagement pressure in which the rise of the engagement pressure of the hydraulic friction engagement device is smooth. Transient engagement pressure control means for controlling the solenoid valve;
The hydraulic control device for a continuously variable transmission for a vehicle according to claim 1, further comprising switching control means for switching the switching valve device when a predetermined time has elapsed from a switching point from the neutral state to the traveling state.

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