JPH0369857A - Hydraulic controller of automatic transmission for vehicle - Google Patents

Abstract

PURPOSE:To prevent retreat of a vehicle from being interfered even if a failure occurs a hydraulic signal generating means by providing a relay valve for outputting a signal to set a retreat preventing valve at a non-preventing position in a combination wherein one of first signal pressure and second signal pressure in a first combination is the same and the other is different. CONSTITUTION:A relay valve 380 is provided for outputting a signal for setting a retreat preventing valve 420 to a preventing position based on first combination among first signal pressure and second signal pressure occurring combinations and the relay valve 380 is provided for outputting a signal for setting the retreat preventing valve 420 to non-preventing position based on a combination wherein at least one of the first signal pressure and the second signal pressure in the first combination is different. Thus even if a failure occurs to a first signal pressure generating means 346 or in a second signal pressure generating means 392, a signal for setting the retreat preventing valve 420 to non-preventing position is output from the relay valve 380 unless failures occur to both means, thereby permitting a vehicle to retreat securely.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a hydraulic control device for an automatic transmission for a vehicle.

2. Description of the Related Art Automatic transmissions for vehicles are known in which power from an engine is transmitted to drive wheels via a gear device that automatically switches to a reverse gear. Examples include a stepped transmission with a reverse gear stage and a belt-type continuously variable transmission with a forward/reverse switching gear device.

In such automatic transmissions for vehicles, a hydraulic control circuit is provided that supplies hydraulic pressure to a reverse hydraulic actuator to establish a reverse gear in connection with the operation of a shift operation member to a reverse operation position. There is. For example, the hydraulic control device described in Japanese Patent Application Laid-Open No. 64-49749 is one example. When the shift operation member of a vehicle traveling forward is operated from the forward range past the neutral range to the reverse range, the transmission of the vehicle traveling forward is automatically switched to reverse gear, so that the power transmission system In addition to sudden loads being applied, drivability may be impaired due to shuffling.

In contrast, the patent application filed earlier by the applicant in 1983-34
As described in the specification of No. 598, a backward prevention valve is provided in the oil passage through which hydraulic pressure is supplied to the reverse hydraulic actuator, and an electromagnetic valve is provided to generate a signal pressure to drive the backward movement prevention valve. A hydraulic control device has been proposed which switches the reverse prevention valve to a blocking position when a shift operation member is operated to a reverse position while the vehicle is moving forward.

Problems to be Solved by the Invention However, in the conventional hydraulic control circuit as described above, the signal pressure is normally generated by a single signal pressure generating means including a solenoid valve driven by an electric signal from a control device. is configured so that it can be generated. For this reason,
For example, if an abnormality occurs such as a solenoid valve becoming stuck due to dust in the hydraulic oil, the reverse prevention valve will remain in the blocking position and the reverse gear will not be set, causing the control device to issue an electrical signal to move the vehicle backwards. There were cases where the vehicle could not go backwards even though the power was being output.

The present invention has been made against the background of the above circumstances,
An object of the present invention is to provide a hydraulic control device for an automatic transmission for a vehicle that allows the vehicle to move backward without any problem even if an abnormality occurs in the hydraulic signal generating means.

Means for Solving the Problems The gist of the present invention to achieve the above object is to provide a vehicle in which the power of an engine is transmitted to a drive shaft through a gear device that automatically switches to a reverse gear. In an automatic transmission, a hydraulic control circuit is configured to supply a hydraulic pressure for establishing the reverse gear to a reverse hydraulic actuator in connection with operation of a shift operation member to a reverse operation position, the hydraulic control circuit supplying hydraulic pressure to a reverse hydraulic actuator. a reverse prevention valve inserted in an oil passage to which hydraulic pressure is supplied to the reverse gear, and positioned in two positions: a blocking position for preventing establishment of the reverse gear and a non-blocking position for allowing establishment of the reverse gear; (2) First
(3) a first signal pressure generating means for generating a signal pressure; and (3) a second signal pressure generating means.
a second signal pressure generating means for generating a signal pressure; and (4) setting the retreat prevention valve to a blocking position based on a first combination of the generation states of the first signal pressure and the second signal pressure. and a signal for setting the retraction prevention valve to a non-blocking position when one of the first signal pressure and the second signal pressure in the first combination is in the same state and the other is in a different state. and a relay valve that outputs.

Operation and Effects of the Invention With this configuration, a signal for setting the retreat prevention valve to the blocking position is output based on the first combination of the generation states of the first signal pressure and the second signal pressure. while the first signal pressure and the second signal pressure in the first combination are
Since a relay valve is provided that outputs a signal for setting the retreat prevention valve to a non-blocking position based on a combination different from at least one of the signal pressures, even if the first signal pressure generating means or the second signal pressure Even if an abnormality occurs in the generating means, a signal for setting the reverse blocking valve to the non-blocking position is outputted from the relay valve unless an abnormality occurs in both of them, so that the vehicle can be reliably moved backward.

EXAMPLE Hereinafter, an example of the present invention will be described in detail based on the drawings.

In FIG. 2, the power of the engine 10 is transmitted through a fluid coupling 12 with a lock-up clutch and a belt-type continuously variable transmission (hereinafter referred to as
The power is transmitted to drive wheels 24 connected to a drive shaft 22 via a CVT (CVT) 14, a forward/reverse switching device 16, an intermediate gear device 18, and a differential gear device 20.

The fluid coupling 12 connects a pump impeller 28 connected to the crankshaft 26 of the engine 10 and an input shaft 3 of the CVT 14.
a turbine impeller 32 fixed at zero and rotated by oil from the pump impeller 28; a lock-up clutch 36 fixed to the input shaft 30 via a damper 34;
An engagement side oil chamber 33 connected to a retention side oil passage 322 described below and a release side oil chamber 3 connected to a release side oil passage 324 described below.
5. The inside of the fluid coupling 12 is always filled with hydraulic oil, and for example, when the vehicle speed exceeds a predetermined value,
Alternatively, when the rotational speed difference between the pump impeller 28 and the turbine impeller 32 becomes less than a predetermined value, hydraulic oil is supplied to the retention side oil chamber 33 and hydraulic oil is flowed out from the release side oil chamber 35. The lock-up clutch 36 is engaged, and the crankshaft 26 and the input shaft 30 are directly connected.

On the other hand, when the vehicle speed, etc. falls below a predetermined value, hydraulic oil is supplied to the release side oil chamber 35 and hydraulic oil flows out from the retention side oil chamber 33, thereby releasing the lock-up clutch 36. .

The CVT 14 includes variable pulleys 40 and 42 of the same diameter provided on the input shaft 30 and output shaft 38, respectively, and a transmission belt 44 wound around the variable pulleys 40 and 42.

The variable pulleys 40 and 42 are fixed rotating bodies 46 and 48 fixed to the input shaft 30 and the output shaft 38, respectively, and are provided on the input shaft 30 and the output shaft 38 respectively so as to be movable in the axial direction but not relatively rotatable around the axes. The movable rotating bodies 50 and 52 are
is moved by the primary hydraulic cylinder 54 and secondary hydraulic cylinder 56 that function as hydraulic actuators, the groove width, that is, the hanging diameter (effective diameter) of the transmission belt 44 is changed, and the speed ratio e (
=Rotational speed N of the output shaft 38. at/rotational speed N, I,) of the input shaft 30 is changed. Since the variable pulleys 40 and 42 have the same diameter, the hydraulic cylinders 54 and 56 have similar pressure receiving areas. Typically, the pressure in the driven side of hydraulic cylinders 54 and 56 is related to the tension in transmission belt 44.

The forward/reverse switching device 16 is a well-known double pinion type planetary gear mechanism, and includes a pair of planetary gears 62 and 64 that are rotatably supported by a carrier 60 fixed to an output shaft 58 and mesh with each other. Advance switching device 1
A sun gear 66 that is fixed to the input shaft (output shaft of the CVT 14) 38 of No. 6 and meshes with the planetary gear 62 on the inner peripheral side, a ring gear 68 that meshes with the planetary gear 64 on the outer peripheral side, and a reverse drive for stopping the rotation of the ring gear 68. brake 70, the carrier 60, and the input shaft 38 of the forward/reverse switching device 16.
A forward clutch 72 is provided to connect the forward drive clutch 72 and the forward drive clutch 72. The reverse brake 70 and the forward clutch 72 are hydraulically operated friction engagement devices, and when they are not engaged, the forward/reverse switching device 16 is in a neutral state and power transmission is cut off. . However, when the forward clutch 72 is engaged, the output shaft 38 of the CVT 14 and the output shaft 58 of the forward/reverse switching device 16 are directly connected, and power in the forward direction of the vehicle is transmitted. In addition, the reverse brake 70
When engaged, the rotation direction is reversed between the output shaft 38 of the CVTI 4 and the output shaft 58 of the forward/reverse switching device 16, so that power in the backward direction of the vehicle is transmitted.

FIG. 1 shows in detail the hydraulic control circuit of FIG. 2 for controlling a vehicle power transmission system. oil pump 74
constitutes the hydraulic power source of this hydraulic control circuit, and is integrally connected with the pump impeller 28 of the fluid coupling 12 so that it is constantly rotationally driven by the crankshaft 26. The oil pump 74 sucks the hydraulic oil that has returned to an oil tank (not shown) through the strainer 76, and also sucks the hydraulic oil that has been returned through the return oil passage 78 and pumps it to the first line oil passage 80. . In this embodiment, the hydraulic oil in the first line oil passage 80 is leaked to the return oil passage 78 and the lock-up clutch pressure oil passage 92 by the overflow (relief) type first pressure regulating valve 100, so that the hydraulic oil in the first line oil passage 80 is leaked to the return oil passage 78 and the lockup clutch pressure oil passage 92. The first line oil pressure P11 in the oil passage 80 is regulated. In addition, the first line oil pressure p is controlled by the second pressure regulating valve 102 of the pressure reducing valve type.
By reducing the pressure of H, the second line in the second line oil passage 82
The line oil pressure Pffi2 is regulated.

First, the configuration of the second pressure regulating valve 102 will be explained. As shown in FIG. 3, the second pressure regulating valve 102 includes a spool valve 11 that opens and closes between the first line oil passage 80 and the second line oil passage 82.
0, spring seat 112, return spring 11
4. It is equipped with a plunger 116. Spool bento 11
0, a first land 118 and a second land 118 having larger diameters in order of diameter.
A land 120 and a third land 122 are formed in this order.

A chamber 126 is provided between the second land 120 and the third land 122, into which the second line oil pressure Pf is introduced as feedback pressure through the throttle 124, and the spool valve 110 is closed by the second line oil pressure PEt. It is designed to be biased toward the valve. In addition, spool valve 110
A chamber 130 is provided on the end face side of the first land 118, through which a speed specific pressure Pe (described later) is guided through a throttle 128, and the spool valve element 110 is urged in the valve closing direction by the speed specific pressure Pe. It has become so. Inside the second pressure regulating valve 102, the biasing force of the return spring 114 in the valve opening direction is applied to the spool valve element 110 through the spring seat 112.
has been granted. Further, a land 117 and a land 119 having a slightly larger diameter than the land 117 are formed on the plunger 116, and a chamber 132 for applying a throttle pressure P-, which will be described later, is provided on the end surface side of the land 117. The spool valve element 110 is biased in the valve opening direction by this throttle pressure Pth.

Therefore, the pressure receiving area of the first land 118 is A, the second land 118 is
Assuming that the area of the cross section of the land 120 is A2, the area of the cross section of the third land 122 is A3, the pressure receiving area of the land 117 of the plunger 116 is A4, and the urging force of the return spring 114 is W, the spool valve element 110 is calculated by the following formula ( Basically, it is balanced at the position where 1) holds true. That is, by moving the spool valve element 110 according to formula (1), the hydraulic oil in the first line oil passage 80 led to the port 134a flows into the second line oil passage 82 via the port 134b. state and port 134b
The state in which the hydraulic oil in the second line oil passage 82 that is led to the drain port 134c that is in communication with the drain is repeated, and the second line oil pressure P12 is generated. Since the second line oil passage 82 is a relatively closed system, the second pressure regulating valve 102 operates at a relatively high first line oil pressure P2. By reducing the pressure, the second line oil pressure PR2 is generated as shown in FIG.

Pj2z=(A<・Pt1.+W A+Pe)/(A
(1) Note that between the first land 118 and the second land 120 of the spool valve 110, there is a first relay valve 380, which will be described later.
A chamber 136 is provided through which a signal pressure P3,5 is introduced, and the spool valve 110 receives the signal pressure P. 3
．． When the valve is biased in the valve closing direction, the second line oil pressure Pit is reduced in accordance with the magnitude of the bias.

Furthermore, the land 117 of the plunger 116 and the land 1
19, a control pressure P 5 is provided via the first relay valve 380, a second relay valve 440 (described later), and a throttle 135.
A chamber 133 for applying oLs is provided,
The second line pressure Pit is the signal pressure P3°3. The pressure is increased accordingly. The characteristics of the second line oil pressure in the above case will be described in detail later.

As shown in FIG. 4, the first pressure regulating valve 100 includes a spool valve element 140, a spring seat 142, a return spring 144, a first plunger 146, and a second land 155 having the same diameter as the second land 155 of the first plunger 146. Each has a plunger 148. The spool valve 140 opens and closes between the port 150a communicating with the first line oil passage 80 and the drain port 150b or 150c, and the first line oil pressure Pffi as a feedback pressure is applied to the end surface of the first land 152. , through a throttle 151, is provided, and the spool valve element 140 is biased in the valve opening direction by the first line oil pressure PP, . Spool bento 1
A chamber 156 for introducing the throttle pressure pth is provided between a first land 154 and a second land 155 of the first plunger 146, which are provided coaxially with the first plunger 40, and
A chamber 157 is provided between the second land 155 and the second plunger 148 for guiding the hydraulic pressure Ph in the primary side hydraulic cylinder 54 via the branch oil passage 305. A chamber 158 is provided for guiding the second line oil pressure P12. Since the biasing force of the return spring 144 is applied to the spool valve element 140 in the valve closing direction via the spring seat 142, the pressure-receiving area of the first land 152 of the spool valve element 140 is defined as AS and the pressure receiving area of the first land 152 of the first plunger 146. Assuming that the cross-sectional area of the first land 154 is A6, the cross-sectional area of the second land 155 and the second plunger 148 is A7, and the biasing force of the return spring 144 is W, the spool valve 140 is located at a position where the following formula (2) is satisfied. and the first line oil pressure P
j2. is regulated.

pl, = ((p,, Or pz z) ・At+Pth(Aa
A? ) +W) /As・・・・・(2) In the first pressure regulating valve 100, the negative side hydraulic cylinder 5
4 internal hydraulic pressure pin is the second line hydraulic pressure Pffi (in steady state, Pffi2=ff side hydraulic cylinder 56 internal hydraulic pressure P.

ut ), the first plunger 146 and the second plunger 148 are separated, and the thrust by the hydraulic pressure Pi in the next hydraulic cylinder 54 acts on the spool valve element 140 in the valve closing direction. However, -next side hydraulic cylinder 5
4 internal hydraulic pressure p in is lower than the second line hydraulic pressure Pf2, the first plunger 146 and the second plunger 148
Because of this, a thrust force by the second line hydraulic pressure Plt acting on the end surface of the second plunger 148 acts on the spool valve element 140 in the valve closing direction. That is, −
The second plunger 148, which receives the hydraulic pressure P in the next side hydraulic cylinder 54 and the second line hydraulic pressure Pi, applies an operating force based on the higher of these hydraulic pressures to the spool valve element 1.
40 in the valve closing direction. Note that a chamber 160 provided between the first land 152 and the second land 159 of the spool valve 140 is open to drain.

Returning to FIG. 1, the throttle pressure pth represents the actual throttle valve opening θ in the engine 10,
It is generated by the throttle valve opening detection valve 180. Further, the speed specific pressure Pe represents the actual speed ratio of the CT 14, and is generated by the speed ratio detection valve 1B2. The throttle valve opening detection valve 180 includes a cam 184 that is rotated together with the throttle valve (not shown), and a plunger that engages with the cam surface of the cam 184 and is driven in the axial direction in relation to the rotation angle of the cam 184. 186 and
Plunger 186 applied via spring 188
By being positioned at a position where the thrust from
ff, and generates a throttle pressure Pth corresponding to the actual throttle valve opening θth.
0. FIG. 5 shows the relationship between the throttle pressure P and the actual throttle valve opening θ.
Throttle pressure P or first pressure regulating valve 100 through oil passage 84
, the second pressure regulating valve 102, the third pressure regulating valve 220, and the lock-up clutch pressure regulating valve 310, respectively.

The speed ratio detection valve 182 also includes a detection rod 192 that is in sliding contact with the input side movable rotating body 50 of the CVT 14 and is moved in the axial direction by an amount of displacement equal to the amount of displacement in the axial direction. The spring 194 correspondingly transmits the biasing force, and while receiving the biasing force from the spring 194, the second line hydraulic pressure P2□ is placed at a position where the thrusts of both are balanced, thereby discharging to the drain. It is equipped with a spool valve 198 that changes the flow rate. Therefore, for example, as the speed ratio e increases, C
When the movable rotary body 50 approaches the fixed rotary body 46 on the input side of the VT 14 (■ groove width is reduced), the detection rod 192 is pushed in. Therefore, the oil is supplied from the second line oil passage 82 through the orifice 196 and the spool valve 198
As a result, the flow rate of the hydraulic oil discharged to the drain is reduced, so that the hydraulic pressure downstream of the orifice 196 is increased. This working oil pressure is the speed specific pressure Pe, and as shown in FIG. 6, it increases as the speed ratio e increases. Then, the velocity specific pressure Pe generated in this way
are supplied to the second pressure regulating valve 102 and the third pressure regulating valve 220 through the oil passage 86, respectively.

Here, the speed ratio detection valve 182 has an orifice 196
Since the speed specific pressure Pe is generated by changing the release amount of the hydraulic oil of the second line hydraulic pressure P12 supplied from the second line oil path 82 through the
While e is limited to a value greater than or equal to the second line oil pressure Pet, the second pressure regulating valve 102 that operates according to (1) 2 reduces the second line oil pressure P12 as the speed specific pressure Pe increases. let Therefore, when the speed specific pressure Pe increases to a predetermined value and becomes equal to the second line oil pressure Pf,
After that, both become saturated and become constant.

FIG. 7 shows the output characteristics of the second line oil pressure Pf2 that is regulated in the second pressure regulating valve 102 in relation to the above-mentioned speed specific pressure Pe. That is, the transmission belt 44 shown in FIG. 8 required for the low-pressure side line oil pressure in relation to the speed ratio e.
Characteristics that approximate the ideal curve for setting the tension to the optimum value can be obtained only by the hydraulic circuit, and when the second line hydraulic pressure P12 is generated using a continuously controlled electromagnetic pressure control servo valve, The advantage is that the hydraulic circuit is significantly cheaper in comparison.

The third pressure regulating valve 220 generates an optimal third line oil pressure PA3 for operating the reverse brake 70 and the forward clutch 72 of the forward/reverse switching device 16. This third pressure regulating valve 220 includes a spool valve 222 that opens and closes between the first line oil passage 80 and the third line oil passage 88.
, spring seat 224, return spring 226
, and a plunger 228. A chamber 236 is provided between the first land 230 and the second land 232 of the spool valve 222, into which the third line oil pressure Pffi is introduced as feedback pressure through the throttle 234. It is biased in the valve closing direction by line oil pressure PL. Furthermore, a chamber 240 is provided on the first land 230 side of the spool valve element 222, through which the speed specific pressure Pe is guided, and the spool valve element 222 is urged in the valve closing direction by the speed specific pressure Pe. It is becoming increasingly popular. Inside the third pressure regulating valve 220, a biasing force in the valve opening direction of a return spring 226 is applied to the spool valve element 222 via a spring seat 224. Further, a chamber 242 for applying a throttle pressure Pth is provided on the end face of the plunger 228, and the spool valve element 222 is urged in the valve opening direction by the throttle pressure Pth. Further, a chamber 248 is provided between the first land 244 of the plunger 228 and the second land 246 having a smaller diameter than the first land 244 for guiding the third line hydraulic pressure P13 only during reverse movement. Therefore, the third line oil pressure Pf is regulated to an optimal value based on the speed specific pressure Pe and the throttle pressure P, using an equation similar to equation (1) above. This optimal value is
This is a necessary and sufficient value to ensure that torque can be transmitted without slipping in the forward clutch 72 or the reverse brake 70. Furthermore, when the vehicle is traveling in reverse, the third line oil pressure P23 is guided into the chamber 248, so the force that urges the spool valve element 222 in the valve opening direction is increased and the third line oil pressure P13 is increased. Thereby, in the forward clutch 72 and the reverse brake 70, suitable torque capacities can be obtained respectively during forward movement and reverse movement.

The third line oil pressure Pffi is regulated as described above.

The forward clutch 7 is operated by the manual valve 250.
2 or the reverse brake 70. That is, the manual valve 250 is
It is equipped with a spool valve 254 that is moved in conjunction with the operation of the vehicle's shift lever 252, and has L (low), S
(second) and D (drive) ranges, the third line oil pressure P13 is exclusively output from the output boat 258 and the forward clutch 72 is operated.
At the same time, the oil is allowed to drain from the reverse brake 70 to the drain. On the other hand, when the operation is in the R (reverse) range, the third line hydraulic pressure P13 is transferred from the output port 256 to the boat 42 of the reverse inhibit valve 420.
2a and 422b, and further supplies the oil to the reverse brake 70 through the reverse inhibit valve 420, while at the same time allowing drainage from the forward clutch 72.
(neutral) and P (parking) ranges, oil is allowed to drain from both the forward clutch 72 and the reverse brake 70. Incidentally, the accumulators 342 and 340 are for gradually increasing the hydraulic pressure to smoothly advance frictional engagement, and are connected to the forward clutch 72 and the reverse brake 70, respectively. Further, the shift timing valve 210 closes the throttle 212 in response to an increase in the hydraulic pressure in the hydraulic cylinder of the forward clutch 72, thereby adjusting the transient flow rate of the flow of people.

The first line oil pressure Pffi regulated by the first pressure regulating valve 100 and the second line oil pressure Pffi regulated by the second pressure regulating valve 102 are connected to the speed change control valve in order to adjust the speed ratio e of the CVT 14. The device 260 supplies one and the other of the primary hydraulic cylinder 54 and the secondary hydraulic cylinder 56 . The speed change control valve device 260 is composed of a speed change direction switching valve 262 and a flow rate control valve 264. Note that the fourth line oil pressure P1 is used to drive the speed change direction switching valve 262 and the flow rate control valve 264.
m is generated by the fourth pressure regulating valve 170 based on the first line oil pressure pH, and is guided by the fourth line oil passage 370.

The fourth pressure regulating valve 170 includes a spool valve element 171 that opens and closes between the first line oil passage 80 and the fourth line oil passage 370, and a spring 172 that biases the spool valve element 171 in the valve opening direction. We are prepared.

Between the first land 173 and the second land 174 of the spool valve element 171 is a chamber 176 into which a fourth line hydraulic pressure Pffi is introduced to act as feedback pressure.
is provided, while the spring 1 of the spool valve 171
On the end face side of the plunger 175 that comes into contact with the end part on the 72 side,
A chamber 177 is provided for introducing a signal pressure P 5ets, which will be described later, to act in the valve opening direction, and the end surface of the spool valve element 171 on the non-spring 172 side is open to the atmosphere. In the fourth pressure regulating valve 170 configured in this way, the spool valve 1
71 is a biasing force in the valve closing direction based on the feedback pressure corresponding to the fourth line oil pressure P14, a biasing force in the valve opening direction by the spring 172, and a signal pressure P. As a result, the fourth line oil pressure Pf is operated so as to be balanced with the biasing force in the valve opening direction based on .

is the signal pressure P8°5, which will be described later. The pressure is regulated to a value corresponding to the size of.

As shown in detail in FIG. 9, the speed change direction switching valve 262 is
a spool valve controlled by the first solenoid valve 266 and communicating with the drain;
A boat 278b communicates with a connecting oil passage 270, a second connecting oil passage 272 provided with a first throttle 271, and a third connecting oil passage 274, respectively.

278d, and 278f, a boat 278c to which the first line hydraulic pressure PlI is supplied through the throttle 276, and a first line hydraulic pressure PlI.
A port 278b to which line hydraulic pressure Pf is supplied, and a second
A 278g boat to which line hydraulic pressure Pffi2 is supplied,
The deceleration side position (
A spool valve element 280 is slidably arranged between an on-side position) and a speed-increasing side position (off-side position) which is the other end of the movement stroke (lower end in the figure), and this spool valve element 2
Spring 282 that biases 80 toward the speed increasing position
It is equipped with The spool valve 280 is provided with four lands 279a, 279b, 279C, and 279d. Spring 28 of the spool valve 280
The end face on the second side is open to the atmosphere. However, when the first electromagnetic valve 266 is in the on state, that is, in the closed state, the fourth line hydraulic pressure pHa regulated by the fourth pressure regulating valve 170 is applied to the lower end surface of the spool valve element 280. When the solenoid valve 266 is in the OFF state, that is, in the open state, the throttle 2
The pressure downstream of 84 is exhausted and the fourth line oil pressure pHa is not applied. When the first solenoid valve 266 is in the ON side shown in the figure, the shift direction switching valve 262 is also in the ON side shown in the figure, and the first solenoid valve 266 is in the ON side shown in the figure.
When the state shown on the FF side is reached, the shift direction switching valve 262 is also in the position shown on the OFF side in the figure. For this reason, the first
During the period when the solenoid valve 266 is in the on state, the spool valve 2
80 is positioned at the deceleration side position and the drain boat 278
a and boat 278b, port 278e and port) 2
78f is opened, and the baud) 27
8b and 2780, ports 278d and 278e, and boats 278r and 278g are closed, but during the period when the first solenoid valve 266 is in the OFF state, the spool valve element 280 is in the speed increasing side position. , the switching state is reversed to that described above.

The flow rate control valve 264 is a spool valve controlled by a second electromagnetic valve 268, and in this embodiment functions as a variable speed control valve. The flow rate control valve 264 is connected to a boat 286a that communicates with the downstream hydraulic cylinder 54 via the primary oil passage 300 and to the second connection oil passage 272, the first connection oil passage 270, and the third connection oil passage 274. ports 286b and 286d, which communicate with each other, and the secondary oil passage 30.
2) which communicates with the secondary hydraulic cylinder 56 via 2
86c, and the flow rate non-suppressing side position in the increasing speed change mode, which is one end of the moving stroke (the upper end of the figure), and the flow rate suppressing side position in the increasing speed changing mode, which is the other end of the moving stroke (the lower end of the figure). It includes a spool valve element 288 that is slidably disposed, and a spring 290 that urges the spool valve element 288 toward the flow rate suppression side position. The spool valve 288 has three lands 287a, 287b, 28 for opening and closing between each port.
7c is provided. Similar to the speed change direction switching valve 262, no hydraulic pressure is applied to the end surface of the spool valve element 288 on the spring 290 side because it is open to the atmosphere. However, when the second solenoid valve 268 is in the on state, that is, in the closed state, the fourth line hydraulic pressure Pig regulated by the fourth pressure regulating valve 170 is applied to the lower end surface of the spool valve element 288, and in the off state, In other words, in the open state, the aperture 292
The pressure on the downstream side is exhausted and the fourth line oil pressure Pla is not applied. The second solenoid valve 268 is turned ON as shown in the figure.
When the state shown on the side is reached, the flow control valve 264 is in the operating position shown on the ON side in the figure, and the second solenoid valve 268 is in the OFF position shown on the figure.
When the state shown on the side is reached, the flow control valve 264 is turned OFF as shown in the figure.
This is the operating position shown on the side. Therefore, during the period when the second solenoid valve 268 is in the on state (duty ratio is 100%), the spool valve element 288 is positioned at the flow rate non-suppression side position, and the port 286a and the boat 286b are 286C and 286d are opened, but the second solenoid valve 268 is in the off state (duty ratio is 0%).
), the spool valve element 288 is positioned at the flow rate suppression side position, resulting in a switching state opposite to that described above.

The secondary hydraulic cylinder 56 includes a bypass oil passage 296 and a check valve 298 that are parallel to each other.
It is connected to the second line oil passage 82 via 95. The check valve 298 is activated when the first line hydraulic pressure Pl is supplied to the secondary hydraulic cylinder 56 during deceleration shifting or engine braking in which the pressure inside the secondary hydraulic cylinder 56 is relatively high. , secondary hydraulic cylinder 56
A large amount of the hydraulic oil inside flows out to the second line oil passage 82, and the hydraulic pressure P inside the secondary hydraulic cylinder 56 decreases. ut (=Pj2.)
In addition, during a gradual deceleration shift, the second line hydraulic pressure Pf is
This is to allow hydraulic oil to be supplied into the tank 6. Further, the throttle 296 and the check valve 298 suitably alleviate the pulsation that occurs in the hydraulic pressure P out in the secondary hydraulic cylinder in synchronization with the duty drive of the flow rate control valve 264 . That is, the hydraulic pressure P in the secondary hydraulic cylinder. This is because the spike-like upper peak in the pulsation of ut is released by the throttle 296, and the lower peak of PoutO is compensated for through the check valve 298. In addition, check valve 298
The valve seat 299 has a planar seat surface, the valve element 301 has a planar contact surface that comes into contact with the seat surface, and a spring that urges the valve element 301 toward the valve seat 299. 30
3, and is designed to open with a pressure difference of about 0.2 kg/cm''.

Further, in the − downstream oil passage 300, the second connection oil passage 272
A second throttle 273 is provided between the confluence point of the branch oil passage 305 and the branch point of the branch oil passage 305 . Here, the throttle 273 determines the speed at the time of rapid deceleration and shifting, and is set so that the speed is maximum within a range where slippage of the transmission belt 44 does not occur during rapid deceleration and shifting. Further, the aperture 271 and the aperture 296 determine the speed during slow speed increase, and the aperture 276 determines the speed during rapid deceleration.

Therefore, when the first solenoid valve 266 is on,
Regardless of the operating state of the second electromagnetic valve 268, the speed ratio e of the CVT 14 is changed in the deceleration direction. For example, when the second solenoid valve 268 is in the on state, the hydraulic oil in the first line oil passage 80 is transferred to the boat 278e, the boat 278f, the third connection oil passage 274, the boat 286d, and the secondary side oil of the boat 286C1. The flow is caused to flow into the secondary hydraulic cylinder 56 through the passage 302, while the secondary hydraulic cylinder 5
The hydraulic oil in 4 is the -next side oil passage 300, the boat 286a,
Boat 1-286b, first connection oilway 270, boat 278
b. It is discharged to the drain through the drain boat 278a. As a result, the speed ratio e
is rapidly changed in the direction of deceleration.

Further, when the second solenoid valve 268 is turned off while the first solenoid valve 266 is in the on state, the hydraulic oil in the second line oil passage 82 flows through the throttle 295 provided in parallel in the bypass oil passage 295. The hydraulic oil in the secondary hydraulic cylinder 54 is supplied through the check valve 298 into the secondary hydraulic cylinder 56, and the hydraulic oil in the downstream hydraulic cylinder 54 is supplied to the secondary hydraulic cylinder 54 through a small gap formed actively or inevitably in the sliding part of the piston. is gradually discharged through the As a result, (
As shown in c), the speed ratio e is gradually changed in the deceleration direction.

Then, when the first solenoid valve 266 is in the on state, the second solenoid valve 266
When the solenoid valve 268 is duty-driven, the above (
Since the speed change state is intermediate between (a) and (c), the speed ratio e is changed to the deceleration side at a speed corresponding to the duty ratio of the second electromagnetic valve 268.

FIG. 10(b) shows this state.

Conversely, when the first solenoid valve 266 is off, the second
Regardless of the operating state of the electromagnetic valve 268, the speed ratio e of the CVT 14 is changed in the speed increasing direction (increasing direction of the speed ratio e). For example, if the second solenoid valve 268 is turned on while the first solenoid valve 266 is off, the first solenoid valve 268 is turned on.
The hydraulic oil in the line oil passage 80 is
8c.

Boat 278b, first connection oilway 270, boat 286b
, ports 286a, and the downstream oil passage 300, and flow into the primary hydraulic cylinder 54 through the boats 278e, 278d, the second connection oil passage 272, and the downstream oil passage 300. While the hydraulic oil in the secondary hydraulic cylinder 56 is
Secondary oil passage 302, bow) 286c, port 286d
, third connection oilway 274, boat 278f, boat 278
g and is discharged to the second line oil passage 82. As a result, the speed ratio e is quickly changed in the direction of speed increase, as shown in (f) of FIG.

Furthermore, if the second solenoid valve 268 is turned off while the first solenoid valve 266 is off, the first connection oil passage 270 is closed by the flow rate control valve 264, so the first line oil passage The hydraulic oil in 80 is exclusively supplied to the primary side hydraulic cylinder 5 through the second connecting oil passage 272 equipped with the first throttle 271.
At the same time, the hydraulic oil in the secondary hydraulic cylinder 56 is gradually discharged to the second line oil passage 82 through the throttle 296. Therefore, by the action of the first throttle 271 and the throttle 296, the speed ratio e is gradually changed in the direction of speed increase, as shown in FIG. 10(d).

Then, when the first solenoid valve 266 is in the off state, the second solenoid valve 266
When the solenoid valve 268 is duty-driven, the above (
Since the speed change state is intermediate between (v) and (d), the speed ratio e is changed to the speed increasing side at a speed corresponding to the duty ratio of the second electromagnetic valve 268.

(E) in FIG. 10 shows this state.

Here, the first line oil pressure pH in the CVT 14 is desired to have an oil pressure value as shown in FIG. 11 during normal drive driving (when the driving torque T is positive), and a hydraulic value as shown in FIG. 11 during engine braking driving (when the driving torque T is negative), a hydraulic pressure value as shown in FIG. 12 is desired. Figures 11 and 12 both show the oil pressure values required when the speed ratio e is varied within the entire range with the input shaft 30 being rotated with a constant shaft torque. It is something. In this embodiment, since the pressure receiving areas of the negative hydraulic cylinder 54 and the secondary hydraulic cylinder 56 are equal, during normal drive running as shown in FIG. 5
Hydraulic pressure P in 6. ut, during engine braking driving as shown in FIG. 12, Po, t > Pin, and in both cases, the hydraulic pressure in the driving side hydraulic cylinder>the hydraulic pressure in the driven side hydraulic cylinder.

Since the above pin in during normal drive running generates the thrust of the hydraulic cylinder on the drive side, it is necessary to make sure that the hydraulic cylinder can generate the thrust to obtain the target speed ratio and to reduce power loss. In order to do this, it is desirable that the first line oil pressure Pffi is regulated to a value that is the sum of the above pin and a necessary and sufficient margin oil pressure α.

However, it is impossible to adjust the first line oil pressure PII shown in FIGS. 11 and 12 based on the oil pressure in one of the hydraulic cylinders. Therefore, in this embodiment, the first pressure regulating valve 100 A second plunger 148 is provided at Pi, l and a second line oil pressure PI! The biasing force based on the higher oil pressure of , , is transmitted to the spool valve element 140 of the first pressure regulating valve 100 . As a result, a curve indicating P87 and P as shown in FIG. 13, for example. ,, during no-load running where the curves indicating t intersect, the first line oil pressure PJ2. is controlled to a value obtained by adding a margin value α to the higher oil pressure value of P, , , and second line oil pressure P12. As a result, the first line oil pressure p
H is controlled to a necessary and sufficient value, and power loss is minimized. Incidentally, the first line oil pressure Pffi,' shown by the broken line in FIG. 13 is the one when the second plunger 148 is not provided, and an unnecessarily large surplus oil pressure is generated in a range where the speed ratio e is large. There is.

The margin value α is a necessary and sufficient value to change the speed ratio e at a desired speed within the entire speed ratio change range of the CVT 14 to obtain the desired speed ratio e, and is clear from equation (2). As such, the first line oil pressure Pl is increased in relation to the throttle pressure Pl. Said first pressure regulating valve 100
The pressure receiving area of each part and the biasing force of the return spring 144 are set in this way. At this time,
The first line oil pressure p regulated by the first pressure valve 100
H is Pi, or P o as shown in FIG.
It increases with at and throttle pressure P, but is saturated at a maximum value corresponding to throttle pressure Pth. As a result, even if the hydraulic pressure P, , l in the primary side hydraulic cylinder 54 increases when the speed ratio e reaches its maximum value and the decrease in the groove width of the primary side variable boob IJ40 is mechanically prevented, The first line oil pressure Pf, which is always controlled to be higher than that by an allowance value α, is prevented from being excessively increased.

Returning to FIG. 1, the hydraulic oil flowing out from the port 150b of the first pressure regulating valve 100 is guided to the lock-up clutch pressure oil passage 92, and is guided to the lock-up clutch pressure regulating valve 310.
The lock-up clutch hydraulic pressure P is suitable for operating the lock-up clutch 36 of the fluid coupling 12.
The pressure is regulated to ET. That is, the lock-up clutch pressure regulating valve 310 receives the lock-up clutch hydraulic pressure PcL as feedback pressure and urges the spool valve element 312 in the valve opening direction, and the spool valve element 312 urges the spool valve element 312 in the valve closing direction. a spring 314;
A chamber 316 to which throttle pressure P is supplied and its chamber 31
6, the plunger 317 urges the spool valve element 312 in the valve closing direction in response to the hydraulic pressure of the spool valve element 3.
12 is operated so that the thrust based on the feedback pressure and the thrust of the spring 314 are balanced, and the hydraulic oil in the lock-up clutch pressure oil passage 92 flows out, thereby increasing the lock-up in accordance with the throttle pressure Pth. Generate clutch oil pressure Pal.

As a result, the lock-up clutch 36 is engaged with a necessary and sufficient engagement force according to the actual output torque of the engine 10. The above Rotta up clutch pressure regulating valve 31
The hydraulic oil that has flowed out from the 0 is sent out through the throttle 318 and the lubricating oil passage 94 to lubricate each part of the transmission, and is also returned to the return oil passage 78.

The third solenoid valve 330 discharges pressure downstream of the throttle 331 to the drain in its OFF state, and generates a signal pressure P 1013 having the same pressure as the fourth line oil pressure Pffi of the fourth line oil passage 370 in its ON state. . The fourth electromagnetic valve 346 discharges pressure downstream of the throttle 344 to the drain in its OFF state, and generates a signal pressure P soz having the same pressure as the fourth line oil pressure P14 in its ON state. The fifth solenoid valve 392 has a throttle 394 in its OFF state.
, and in the ON state, the fourth line hydraulic pressure Pj2. The same signal pressure P 5ols is generated.

In this embodiment, each of the above signal pressures P 5oL3, P 1ot
4. By combining P5ots, multiple types of lock-up clutch engagement and sudden release control, accumulator back pressure control, N range line oil pressure down control, line oil pressure down control at high vehicle speeds, reverse inhibit control, etc. can be performed by combining P5ots. Control is now in place.

The lock-up clutch control valve 320 and lock-up clutch quick release valve 400 related to engagement and quick release control of the lock-up clutch 36 will be described. This lock-up clutch control valve 320 controls the hydraulic oil in the oil passage 92 whose pressure is regulated to the lock-up clutch oil pressure Pet.
Engagement side oil passage 322 and release side oil passage 32 of fluid coupling 12
The lock-up clutch 36 is selectively supplied to the lock-up clutch 3 to engage or disengage the lock-up clutch 36, and the lock-up clutch quick release valve 400
By draining the hydraulic oil that flows out when the lock-up clutch 6 is released without passing through the oil cooler 339, the lock-up clutch 36 is quickly released.

The lock-up clutch control valve 320 is a two-position operating type spool valve, and when the lock-up clutch 36 is engaged (on side in the figure: second position), the lock-up clutch control valve 320 is a boat to which the lock-up clutch hydraulic pressure P□ is supplied. 321c and the boat 321d, the boat 321b and the drain boat 321a, and the boat 321e and the boat 321f, and when the lock-up clutch 36 is released (off side in the figure: first position), the boat 321c, the boat 321b, and the boat 321
d and the boat 321e, a spool valve 326 that connects the boat 321r and the drain boat 321g, and a spring 3 that biases the spool valve 326 toward the release side (off side).
It is equipped with 28. The lower end surface side of the spool valve 326 (
A chamber 332 is provided on the non-spring 328 side) into which a signal pressure P8°L3 generated when the third solenoid valve 330 is in the on state is introduced.

The lock-up clutch quick release valve 400 is a two-position operating type spool valve, and includes a boat 402a that communicates with the clutch pressure oil passage 92 via a throttle 401, and a release side oil passage 32.
port 1-402b that communicates with port 402b that communicates with port 402b that communicates with boat 321b of lock-up clutch control valve 320.
c. Boat 321 of lock-up clutch control valve 320
A boat 402d that communicates with f, a port 402e that communicates with the engagement oil passage 322, and a lock-up clutch control valve 32
The boat 402 communicates with the boat 321d of 0. During normal operation (off side in the figure: 3rd position), the boat 402b communicates with the port 402c, and the boat 402e communicates with the boat 402f, and when suddenly released (on side in the figure: 4th position) is the above position)
402a and boat 402b, boat 402d and port 4
02e, and a spring 40B that urges the spool valve 406 toward the quick release side position. A signal pressure P5.4 generated when the fourth solenoid valve 346 is in the on state is guided to the chamber 410 on the lower end side of the spool valve element 406. As shown in the figure, the on-side and off-side positions of the third solenoid valve 330 and the on-side and off-side positions of the lock-up clutch control valve 320 are made to correspond operationally, and the fourth solenoid valve 346 The on-side and off-side positions of the lock-up clutch quick release valve 400 are operatively made to correspond to the on-side and off-side positions of the lock-up clutch quick release valve 400.

Therefore, if the third solenoid valve 330 is turned on while the fourth solenoid valve 346 is in the off state, a third oil passage for engaging the lock-up clutch 36 is formed, so the lock-up clutch The hydraulic oil in the pressure oil passage 92 is supplied to the fluid coupling 12 through the bow) 321c, the port 321d, the port 402f, the port 402e, and the engagement side oil passage 322, and the hydraulic oil flowing out from the fluid coupling 12 is released. Side oil passage 324, port 402b, bow) 402c,
It is drained from port 321a via port 321b. As a result, the lock-up clutch 36 is engaged.

Conversely, when the fourth solenoid valve 346 is in the OFF state, the third solenoid valve 346
When the solenoid valve 330 is turned off, the spool valve 32
6 is in the on side shown in the figure, and the first oil passage for releasing the lock-up clutch 36 is formed.
Hydraulic oil in lock-up clutch pressure oil passage 92 is po)3
21c, port 321b, port 402c, port 4
02 b.

Hydraulic oil is supplied to the fluid coupling 12 through the release side oil passage 324 and flows out from the fluid coupling 12 through the engagement side oil passage 324.
2, port 402e, port 402f, port 321
d, port 402e, and is drained via oil cooler 339. As a result, the first release mode is set and the lock-up clutch 36 is released.

Furthermore, in this embodiment, when the third solenoid valve 330 and the fourth solenoid valve 346 are turned on, a fourth oil passage for releasing the lock-up clutch 36 is formed, so this second release In the mode, the hydraulic oil in the lock-up clutch pressure oil passage 92 is supplied to the fluid coupling 12 through the port 402a, bow 402b, and release side oil passage 324, and the hydraulic oil flowing out from the fluid coupling 12 is on the engagement side. Oil road 322
, port 402 e, port 402 d, port 321
f, port 402e, and oil cooler 339, and the lock-up clutch 36 is released. As a result, even if the spool valve element 326 of the lock-up clutch control valve 320 is stuck to the on side or the spool valve element 406 of the lock-up clutch quick release valve 400 is stuck to the off side, the first If the lock-up clutch 36 is maintained in the engaged state even if one of the release modes or the second release mode is selected, switching to the other mode prevents the engine from stalling and prevents the vehicle from stalling. will be able to restart. In addition, the spool valve element 326 of the lock-up clutch control valve 320 may become stuck to the off side, or the spool valve element 406 of the lock-up clutch quick release valve 400 may become stuck to the on side, and the first
Even if one of the above release modes or the second release mode is selected, if the lock-up clutch 36 is maintained in the sudden release state, switching to the other mode will cause the hydraulic oil to flow through the oil cooler 339. can be drained, and overheating of the oil can be suitably prevented.

When the lock-up clutch 36 is released as described above, when a sudden release is required as in the case of sudden braking of the vehicle, the fourth solenoid valve 346 is turned off while the third solenoid valve 330 is in the OFF state. is turned on. This allows the second clutch to release the lock-up clutch 36 quickly.
Since the oil passage is formed, the lock-up clutch pressure oil passage 9
The hydraulic oil in 2 is exclusively from port) 402a to port) 402b.
and flows into the fluid coupling 12 via the release side oil passage 324,
The hydraulic oil flowing out from the fluid coupling 12 flows through the engagement side oil passage 322,
It is drained from port 321g via port 402e, port 402d, and port 321r. As a result, the oil is drained without passing through the oil cooler 339, which has a large flow resistance, so that the lock-up clutch 36 is quickly released. FIG. 15 shows the relationship between the mode of the lock-up clutch 36 and the operating states of the third solenoid valve 330 and the fourth solenoid valve 346.

Note that the oil cooler 339 is activated during engagement and disengagement.
The hydraulic oil that is returned to an oil tank (not shown) is relieved by a Tara hydraulic control well 338 provided upstream of the oil cooler 339, so that the pressure is regulated below a certain value. Further, the bypass oil passage 334 guides a portion of the hydraulic oil to the oil cooler 339 in order to cool the hydraulic oil in the oil cooler 339 even when the lock-up clutch 36 is engaged.

The throttles 336 and 337 are connected to the lock-up clutch 36.
This is to set the proportion of hydraulic oil that is guided to the oil cooler 339 during engagement.

Next, the first relay valve 3 is related to accumulator back pressure control, line oil pressure down control in the N range, line oil pressure down control at high vehicle speeds, reverse inhibit control, etc.
80 and the second relay valve 440 will be explained. 1st
The relay valve 380 is connected to the port 442 of the second relay valve 440.
P) 382a communicating with C, signal pressure P3゜3. port 382b to which is supplied, port 3 communicating with chamber 136 of second pressure regulating valve 102 and reverse inhibit valve 420;
82 C, and the drain port 382d, in the on side state shown in the figure, the port 3B2a communicates with the boat 382b, and the port 382c and the drain port 382d, and in the off state shown in the figure, the port 328a is drained, and the port 382b and the port 382c are connected. A signal pressure P $014 is provided in a chamber 388 provided on the non-spring side of the spool valve 384. When is not applied, the spool valve 384 is in the OFF position and the signal pressure P. ,.

is supplied to the chamber 136 of the second pressure regulating valve 102 and the chamber 435 of the reverse inhibit valve 420, but when the signal pressure P5ota is applied to the chamber 388, the spool valve 3
84 is set to the on side, and the signal pressure P5ots is supplied to the port 442C of the second relay valve 440. In the figure, the on and off states shown for the first relay valve 380 correspond to the on and off states of the fourth solenoid valve 346.

The second relay valve 440 communicates with the chamber 133 of the second pressure regulating valve 102 via a throttle 443, and has ports 442b and 442c that are always in communication with each other.

The port 442d and drain port 442e, which communicate with the accumulator 372 and the fourth pressure regulating valve 170, communicate with the drain port 442e in the on-side state in the figure, and communicate with the drain port 442d in the off-side state in the figure. A chamber 448 provided on the non-spring side of the spool valve 444 includes a spool valve 444 that blocks the connection between the spool valve 444 and the spool valve 442e, and a spring 446 that biases the spool valve 444 toward the off-side state.
When the signal pressure P5otz is applied to the spool valve 444, the spool valve 444 is in the OFF position, and the signal pressure P is applied to the chamber 448. , 3 is applied, the spool valve 444
is set to the on side. This allows port 44
2c and 442b to the chamber 13 of the second pressure regulating valve 102.
Signal pressure P, which is supplied to 3. , S are branched when the spool valve 444 is switched from the on to off position, and the accumulator 372 and the fourth pressure regulating valve 17
0 chamber 177 is also supplied. In the figure, the on and off states shown for the second relay valve 440 correspond to the on and off states of the third solenoid valve 330.

Next, accumulators 342 and 340 provided in the forward clutch 72 and the reverse brake 70, respectively.
Explain the back pressure control. When the fifth electromagnetic valve 392 is driven by duty, the oil pressure of the signal pressure P5ots generated on the downstream side of the throttle 394 is changed in accordance with the duty ratio DsS, as shown in FIG. That is, the throttle 394 and the fifth electromagnetic valve 392 receive the signal pressure P.
It functions as a signal pressure generating means for generating 15°. In this way, the drive duty ratio Ds of the fifth solenoid valve 392
Signal pressure P3゜4. which is changed according to S. is supplied to the accumulator 372 and the fourth pressure regulating valve 170 via the oil passage 348 when the first relay valve 380 is turned on and the second relay valve 440 is turned off for back pressure control. .

Here, the back pressure control of the accumulators 340 and 342 is as follows.
Shift shock during N-D shift or N-R shift (
This is done to reduce the locking shock), and suppresses the increase in the oil pressure in the hydraulic cylinder for a predetermined period of time when the clutch is engaged, thereby alleviating the shock.

Therefore, the fourth line oil pressure Pea, which is supplied to the back pressure port 366 of the accumulator 342 for the forward clutch 72 and the back pressure port 368 of the accumulator 340 for the reverse brake 70, is changed by the fourth pressure regulating valve 170, and the accumulator 342.340 controls the relaxation effect.

In the fourth pressure regulating valve 170, the fourth line oil pressure P14 is the signal pressure P. 4. The pressure is regulated to correspond to the pressure.

That is, the signal pressure Pl passes through the first relay valve 380 and the second relay valve 440 during the N-+D shift and the N-+R shift. 4. is being supplied to the chamber 177 of the fourth pressure regulating valve 170, the fourth line oil pressure P14 is at the duty ratio Ds5 of the fifth solenoid valve 392, as shown in FIG.
Since the fifth electromagnetic valve 392 is controlled to a value corresponding to , the fifth electromagnetic valve 392 is driven on duty so as to generate a back pressure suitable for reducing shift shock (maintenance shock). Also,
As the oil pressure in the forward clutch 72 rises to the third line oil pressure Pf, the signal pressure P5ots supplied to the fourth pressure regulating valve 170 is cut off by the second relay valve 440, and the inside of the chamber 177 is When released to the atmosphere, the fourth line hydraulic pressure PJ2. is controlled to a relatively low constant pressure of about 4 kg/cm'' in response to the biasing force of the spring 172 in the valve opening direction.The fourth line oil pressure P4, which is regulated to this constant pressure, is exclusively It is used as a driving oil pressure (pilot oil pressure) for the speed change direction switching valve 262 and the flow rate control valve 264. Therefore, in this embodiment, the fourth pressure regulating valve 1
70 functions as a valve drive hydraulic pressure generating device that generates valve drive hydraulic pressure for driving the speed change direction switching valve 262 and the flow rate control valve 264. Note that the accumulator 372 provided in the oil passage 348 receives a signal pressure Pl related to the duty drive frequency of the fifth solenoid valve 392. 5. This is to absorb the pulsations of the

Next, a description will be given of a portion related to the control to lower the second line oil pressure P12. In order to prevent overload from being applied to the transmission belt 44 due to the centrifugal hydraulic pressure in the low-pressure side hydraulic cylinder, the fourth solenoid valve 346 and the first relay valve 380 are turned off and the fifth solenoid valve is turned off in a high vehicle speed state. 392 is turned on, regardless of the operating states of the third solenoid valve 330 and the second relay valve 440, when the output shaft 38 of the CVT 14 rotates at high speed, the second line mainly supplies the secondary hydraulic cylinder 56. Oil pressure P12 is reduced. That is, the signal pressure Pl passes through the ports 382b and 382c of the first relay valve 380. ,.

(-P l a) is supplied to the chamber 136 of the second pressure regulating valve 102, the second line oil pressure P12 is regulated according to the following equation (3), and as shown in the dashed line in FIG. compared to the normal second line oil pressure shown. As a result, the influence of centrifugal oil pressure in the secondary hydraulic cylinder 56 is eliminated, and the durability of the transmission belt 44 is increased. Such second line oil pressure Pj2. The reduction control is also executed during reverse prohibition control, which will be described later, or when the shift lever 252 is operated to the N range. Note that if the fourth solenoid valve 346 is turned on or the fifth solenoid valve 392
is in the off state, the second line oil pressure P12 is set to the above (
1) Controlled normally according to Eq.

P12= (A,・P+(As −A4)・P,
. , 5+WA1P* (A2 Al)・P,.

ts)/(Ih - to 2)...(3) The reverse inhibit valve 420, which is provided to prohibit reverse during forward travel, is configured to close the third valve from the output port 256 of the manual pulp 250 when it is in the R range. Line oil pressure P1. ports 422a and 422b that are supplied with water, a port) 422c that communicates with the hydraulic cylinder of the reverse brake 70 via an oil passage 423, and a port 422c that communicates with the hydraulic cylinder of the reverse brake 70 through an oil passage 423, and a first port that is the upper end of the movement stroke.
position W (non-blocking position) and the second position (blocking position) which is the lower end
a spool valve 424 slidably disposed between the spool valve 424;
A spring 426 that biases the spool valve element 424 in the valve opening direction toward the first position;
Plunger 42 that abuts the lower end of 4 and has a smaller diameter than that.
8. The spool valve 424 has a first land 430 with a small diameter and a second land 430 with a larger diameter from its upper end.
A land 432 and a third land 434 having the same diameter as the land 432 are formed, and in the chambers 4 and 35 provided on the end surface side of the first land 430, an eleventh J relay valve 380 in an off state is formed.
A signal pressure P5°t5 is supplied through the terminal. A chamber 436 between the first land 430 and the second land 432 and a chamber 437 between the second land 432 and the third land 434 are provided with a third valve from the manual valve 250 only when the R range is operated. Line hydraulic PI! , , are adapted to be actuated, while the spool valve 42
The hydraulic pressure in the reverse brake 70 is applied to the chamber 438 between the plunger 428 and the third line hydraulic pressure P1. :l is constantly supplied. Note that the third line oil pressure Pl of this plunger 428.

The pressure-receiving area on which the spool valve 424 acts is
The land 430 and the second land 432 are used as a pressure receiving area difference and a road between which the land 430 and the second land 432 receive the hydraulic pressure in the chamber 436.

The reverse inhibit valve 42 configured in this way
0 is the biasing force of the spring 426, the reverse brake 70
The signal pressure P is greater than the thrust in the valve opening direction based on the internal oil pressure and the third line oil pressure P13. , S and third line oil pressure P
When the thrust in the valve closing direction based on 13 is exceeded, the spool valve element 424 is moved against the biasing force of the spring 426, and the port 422b and the boat 422C are cut off, and the boat 422C and the drain port 422d are separated. Since the space between the two is communicated with each other, the reverse brake 70 is released to the drain, and establishment of the reverse gear of the forward/reverse switching device 16 is prevented. That is, when the fourth solenoid valve 346 is in the off state, the fifth solenoid valve 392 is in the on state and the signal pressure P5°1 is
．． is generated, the forward/reverse switching device 16 is activated on condition that the shift lever 252 is operated to the R range.
This prevents the reverse gear stage from being established. However, the reverse inhibit valve 420 is different from the fourth solenoid valve 3.
46 is turned on, the fifth solenoid valve 392 is turned off, or the shift lever 252 is operated to a range other than the R range, the spool valve 444 is turned on. The reverse brake 70 is moved according to the biasing force of the spring 426 to communicate with the boat 256 of the manual valve 250. therefore,
When the shift lever 252 is erroneously operated from the D range, past the N range, and into the R range while the fourth solenoid valve 346 is turned off and the fifth solenoid valve 392 is turned on by the electronic control device 460, which will be described later. In this case, the reverse brake 70 is prevented from being engaged, and the forward/reverse switching device 16 is maintained in the neutral state.

The first relay valve 380 is in the off state, that is, the fourth solenoid valve 3
46 is in the off state, the signal pressure P8°5. is connected to the chamber 136 of the second pressure regulating valve 102 through the first relay valve 380.
Since the second line oil pressure Pfz is supplied to the signal pressure P,
. 3. The predetermined pressure is lowered accordingly. This results in N
In the range, the clamping force on the transmission belt 44 is made as low as possible without causing slippage, which not only reduces the noise level of the belt but also increases the durability of the transmission belt 44.

Further, when the first relay valve 380, that is, the fourth solenoid valve 346 is in the on state, and the second relay valve 440, that is, the third solenoid valve 330 is in the on state, the signal pressure P5 is lower than the first relay valve 380. and is supplied to the chamber 133 of the second pressure regulating valve 102 through the second relay valve 440.
The line oil pressure P12 is the signal pressure P. A predetermined pressure is applied depending on the situation. As a result, during braking, etc., during deceleration shifting, sudden deceleration shifting by operating the shift lever 252 from the D range to the L range, and accumulator shift by operating the shift lever 252 from the N range to the D or R range. During back pressure control, the second line oil pressure Pffi.

is enhanced. Therefore, in a state where the transmission belt 44 of the CVT 14 is likely to slip as described above, the tension of the transmission belt 44 (the clamping force on the transmission belt 44) is temporarily increased and the torque transmission capacity is increased. Ru.

FIG. 19 shows the third solenoid valve 330 and the fourth solenoid valve 34 described above.
6. Combinations of operations of the fifth solenoid valve 392 and the resulting operation modes are shown, respectively.

In FIG. 2, an electronic control device 460 includes a first solenoid valve 266 and a second solenoid valve 268 in the hydraulic control circuit of FIG.
, third solenoid valve 330, fourth solenoid valve 346, fifth solenoid valve 3
By selectively driving 92, the speed ratio e of the CVT 14, the engagement state of the fluid coupling 120 and the lock-up clutch 36, and the increase or decrease control of the second line oil pressure Pit are controlled. The electronic control unit 460 includes a CPU, RAM
, ROM, etc., and includes a vehicle speed sensor 462 that detects the rotational speed of the drive wheels 24, an input shaft 30 and an output shaft 3 of the CVT 14,
Input shaft rotation sensor 46 that detects the rotation speed of 8.
4 and an output shaft rotation sensor 466, a throttle valve opening sensor 468 that detects the opening of a throttle valve provided in the intake pipe of the engine 10, an operating position sensor 470 that detects the operating position of the shift lever 252, and a brake pedal. a brake switch 472 for detecting the operation of
Rotational speed N of the engine 10. A signal representing the vehicle speed ■, a signal representing the input shaft rotational speed N i fi, and an output shaft rotational speed N are output from the engine rotation sensor 474 for detecting. uL
A signal representing the throttle valve opening θ, a signal representing the operation position P5 of the shift lever 252, a signal representing the brake operation, and a signal representing the engine rotational speed N0 are supplied, respectively. The CPU in the electronic control unit 460 is RAM
The first electromagnetic valve 2
66, second solenoid valve 268, third solenoid valve 330, 4th'l
A signal for driving the solenoid valve 346 and the fifth solenoid valve 392 is output.

In the electronic control unit 460, initialization is executed when the power is turned on, and then a main routine (not shown) is executed to read input signals from each sensor. The rotational speed N i n of the shaft 30 and the rotational speed N of the output shaft 38.

. ,, the speed ratio e of the CVT 14, the vehicle speed V, etc. are calculated, and the lock-up clutch engagement control and sudden release control of the lock-up clutch 36 and the CV
TI4 speed change control, accumulator back pressure control, reverse prohibition control, second line pressure reduction control, second line pressure increase control, etc. are executed sequentially or selectively.

The speed change control of the CVT 14 is performed, for example, according to the flowchart shown in FIG. Step S
1, input signals etc. from each sensor are read, and based on the read signals, the vehicle speed V,
The rotational speed N in of the input shaft 30, the rotational speed N, )ut of the output shaft 38, the throttle valve opening θ, the shift operation position P5, and the engine rotational speed N are calculated. Step S
2, the predetermined relationship (N,,,” =
f (θi, V.

P, )), the target rotational speed N in of the human power shaft 30 is determined based on the shift operation position P, the throttle valve opening θ, and the vehicle speed ■. This relationship shows that, for example, the required output expressed by the throttle valve opening θ is
In order to generate the fuel efficiency on the minimum fuel consumption rate curve, a plurality of sets are determined in advance for each of the S and L ranges, and are stored in the ROM in the form of a functional formula or a data map. When the shift operation position is in the S or L range, it is a state where sporty driving or enhanced engine braking action is required, so in the relationship selected in the S or L range, driving in the D range is The target rotational speed N i n
is set high. Note that the shift operation position for driving is not limited to the three positions of the S range, the S range, and the L range, but can be set arbitrarily as necessary.

In the subsequent step S3, the control deviation ΔN, (=N, -N, ,) between the actual rotational speed N in and the target rotational speed N in of the input shaft 30 of the CVT 14 is determined. Then, in step S4, one of the plurality of speed change modes shown in FIG. 10 is selected based on the magnitude of the control deviation ΔN, . . . obtained in step S3. This selection method is based on, for example, control deviation Δ
A shift mode corresponding to the region including N i fi is selected. Among the multiple types of hatched areas in Fig. 10, overlapping areas are provided between adjacent areas, but this prevents adjacent shift modes from repeating alternately and resulting in unstable control. It is for the purpose of

When the control deviation ΔN i n takes a value within the overlap region, a shift state close to the current shift mode is selected. For example, the initial control deviation ΔN8. ．． is 25 Orp
When shift mode (b) is selected in m,
When the control deviation ΔN in decreases to 14 Orpm and falls within the overlap between the shift mode (b) and the shift mode (c), the shift mode (b) is selected. Also, the control deviation ΔN from the state where the shift mode (c) is selected. If the shift mode (b) and the shift mode (c) are included in the overlap region, the shift mode (c) is selected.

Then, in step S5, it is determined whether or not the shift mode (B) has been selected, and in step S6, it is determined whether or not the shift mode (E) has been selected. If the shift mode (b) is selected in step S4, the determination in step S5 is affirmative, so in step S7, the duty ratio DSt (%) of the second solenoid valve 268 is determined according to the following equation (4). Calculated. If the shift mode (E) is selected in step S4, the determination in step S6 is affirmative, so in step S8 the duty ratio D of the second electromagnetic valve 268 is
3□ is calculated according to the following equation (5).

D3□=, ・ΔN1, ・ ・ ・(4) D−z”
” Kz・ΔNi, l−...(5) However, K,...
is a constant.

Here, the reason why two types of equations (4) and (5) are used when determining the duty ratio D3□ of the second solenoid valve 268 is that the flow rate characteristics of the flow rate control valve 264 are different in the deceleration direction and the speed increase direction. This is because they are different.

The first solenoid valve 266 and the second solenoid valve 268 are each driven in step 312, which will be described later, at the duty ratio Ds2 determined as described above or in the on or off state determined in step S4. The duty drive of the second solenoid valve 268 is, for example, in the on state for To -D-z/100 hours within a certain period (period) TO, and To.(1-D, 2/100)
It is executed periodically so that the time is turned off. Here, the duty ratio D3□ determined by the above equations (4) and (5) increases the flow rate in proportion to the magnitude of the control deviation ΔN i n . Since the flow rate is controlled in the direction in which the difference is eliminated, the target rotational speed N
Feedback control is executed to match n' with the actual rotational speed N, .

In step S9, each control executed by the third solenoid valve 330 and the fourth solenoid valve 346, namely lock-up clutch engagement and release control, lock-up clutch quick release control, accumulator back pressure control, reverse prohibition control,
A control mode determination routine for determining which control mode of the second line oil pressure reduction control is to be executed is executed. Although this control mode determination routine is not shown, the control mode is determined depending on whether a predetermined condition is satisfied.

For example, when the shift lever 252 is operated to the N range, the third solenoid valve 330 and the fourth solenoid valve 346 are determined to be in the OFF state so as to be in the B mode of FIG.
Further, the fifth solenoid valve 392 is determined to be in the on state. As a result, the second line oil pressure P12 is lowered by a predetermined value in order to prevent noise from the transmission belt 44 in the N range and increase durability. If the vehicle speed V is, for example, 7 to 10)c
If the vehicle is judged to be traveling forward at a speed exceeding a predetermined value of approximately m/h, the third solenoid valve 330, fourth solenoid valve 346, and fifth solenoid valve 392 will not operate even if the vehicle is operated to the R range. The same state is maintained. For this reason, the signal pressure Pso (%) continues to be supplied to the chamber 435 of the reverse inhibit valve 420, so if the shift lever 252 is mistakenly operated to the R range, the signal pressure Pso(%) will be supplied from the port 256 of the manual valve 250 to the chamber of the reverse inhibit valve 420. 3rd line oil pressure Pl to 436.

is supplied, the reverse inhibit valve 420 is operated to the blocking position, and establishment of the reverse gear is prevented.

Further, when the throttle distance θ and the vehicle speed 2 of the vehicle are well known and stored in advance, and the vehicle enters the engagement region of the lock-up clutch engagement diagram (not shown), the engagement mode shown in FIG. 15, that is, the C state shown in FIG. 3rd solenoid valve 3 to be in mode
30 is in the on state and the fourth solenoid valve 346 is in the off state, and the lock-up clutch 36 is engaged. In this state, when the vehicle speed exceeds a predetermined constant value, for example 100) cut/h, the fifth solenoid valve 392 is turned on and the third solenoid valve 392 is set to the D mode in FIG. In addition to the ON state of the valve 330 and the OFF state of the fourth solenoid valve 346, the fifth solenoid valve is determined to be in the ON state.

Thereby, in order to prevent the transmission belt 44 from becoming excessively tensioned due to the centrifugal hydraulic pressure, the second line hydraulic pressure P12 is
is reduced by a predetermined value.

In addition, when the lock-up clutch 36 is in the engaged state, if the vehicle speed ■ and the throttle opening θ go out of the engagement range shown in the diagram in the D range, or if the N range is operated, as shown in FIG. the first release mode or the second release mode, i.e. A or H in FIG.
Both the third solenoid valve 330 and the fourth solenoid valve 346 are determined to be in the on state or the off state so that the mode is set.

As a result, the lock-up clutch 36 is released.

The H mode is selected when the transmission capacity of the CVT 14 is required more than usual, such as when starting the vehicle or shifting from D to L. As a result, the second line oil pressure P12 is increased by a predetermined value, and the clamping force of the transmission belt 44 is increased.

If it is not reverse prohibition control and it is not in N or P range, the rotational speed of the input shaft (output shaft 38) and output shaft 58 in the forward/reverse switching device 16 is determined according to the following equation (6) when in the R range. The difference Nd is calculated from the following equation (6), and in the case of forward ranges such as the D, S, and L ranges, the rotational speed difference Nd is calculated according to the following equation (7).

Nd=lNout-ip-Npl ---(6)N
d= I N, ut-N, cl---(
7) Here, N out is the rotational speed of the output shaft 38 of the CVT 14, Npc is the rotational speed of the carrier 60 of the forward/reverse switching device 16, and ip is the rotational speed of the forward/reverse switching device 1 when traveling in reverse.
It has a gear ratio of 6. The above Npc has a completely one-to-one correspondence with the vehicle speed V, and is obtained according to the following equation (8). Further, the above 12 is obtained from N out and N p c when the reverse brake 70 is fully engaged according to the following equation (9).

N, c=C/V ・ ・ ・ (8) i ,
= Nouc/Npc...(9) However,
C is a constant.

The rotational speed difference Nd obtained as above is determined in advance by R
Judgment reference value C of about 30 rpm, for example, stored in OM
It is determined whether or not it is larger than N.

This determination reference value CN is a value for determining whether or not engagement of the forward clutch 72 or the reverse brake 70 is completed. If it is determined that the actual rotational speed difference Nd is not larger than the judgment reference value CM, the maintenance is completed and back pressure control is not executed, but the actual rotational speed difference Nd
If it is determined that d is larger than the determination reference value CM, the off state of the third solenoid valve 330, the on state of the fourth solenoid valve 346, and the on or duty drive state of the fifth solenoid valve 392 are determined, The accumulator backpressure control mode shown at F in FIG. 19 is selected. The fifth solenoid valve 39 at this time
The duty ratio of 2 is changed according to a pre-stored time function. As a result, the back pressure of the accumulator 342 or 340 is gradually changed during the N-+D shift operation or the N→R shift operation, so that the forward clutch 72 or the reverse brake 70 is smoothly engaged.

When the brake switch 472 is in the ON state in the forward range and the release conditions for the lock-up clutch 36 are satisfied, that is, the vehicle speed is lower than a pre-stored judgment reference value, the lock-up clutch quick release control mode (E ) is selected, then the lock-up clutch release control mode (G) is selected. That is, the lock-up clutch quick release control mode (E) is selected by determining the off state of the third solenoid valve 330, the on state of the fourth solenoid valve 346, and the off state of the fifth solenoid valve 392. After a predetermined period of time has elapsed, only the third solenoid valve 330 is turned on, thereby selecting the lock-up clutch release control mode (G).

In addition, in the fail-safe step, an abnormality (failure) of the lock-up clutch control valve 320 and the lock-up clutch quick release valve 400 is detected, and the first release mode shown in FIG. Alternatively, select either the second release mode. for example,
Even if the vehicle speed V or the throttle opening θ is out of the engagement range of the lock-up clutch 36 in the retention diagram and the fluid coupling 12 is in either the first release mode or the second release mode, Rotation difference between input and output shafts (=N, -N,,
) is smaller than a predetermined judgment reference value, for example, 30 rpm, and it is determined that the lock-up clutch 36 is engaged, or it is determined that the lock-up clutch 36 is engaged based on the engine stalling when restarting. If so, the other release mode is selected. Further, the third solenoid valve 330 is turned on so that the vehicle speed V or the throttle opening θ is within the engagement range of the lock-up clutch 36 in the engagement diagram, and the engagement mode shown in FIG. 15 is established. 4th solenoid valve 3
46 is in the off state, the fluid coupling 12
If it is determined that the lock-up clutch 36 is released based on the fact that the rotation difference between the input and output shafts (=N, -N, . . . ) is larger than a predetermined judgment reference value, the lock-up clutch 36 is actually Since the control valve 320 is in the off state and the lock-up clutch quick release valve 400 is in the on state, resulting in the quick release mode, the other release mode is selected to ensure cooling of the hydraulic oil.

As described above, after the control mode is selected in step S9, it is determined in step S12 whether or not the back pressure control mode shown in F in FIG. 19 is selected. If it is the back pressure control mode, the fifth solenoid valve 3 is activated in step S12.
The duty ratio I)ss of 92 is determined, but if it is not the back pressure control mode, step S12 is directly executed.

In this step S12, the first solenoid valve 266 corresponding to each control mode determined in steps S4 and S9,
Second solenoid valve 268, third solenoid valve 330, fourth solenoid valve 34
A drive signal is output so that the fifth solenoid valve 392 and the fifth electromagnetic valve 392 are turned on or off.

As described above, according to this embodiment, the B mode of FIG. 19, which prevents establishment of the reverse gear when the shift lever 252 is operated to the R range when the vehicle is traveling forward at a predetermined vehicle speed or higher, is set to the B mode of FIG. The selection is made when the fourth solenoid valve 346 is in the off state and the fifth solenoid valve 392 is in the on state.
A 19th gear that allows establishment of a reverse gear when the shift lever 252 is operated to the R range while the vehicle is stopped, etc.
In the G mode shown in the figure, the fourth solenoid valve 346 is on and the fifth solenoid valve 346 is on.
The selection is made when the solenoid valve 392 is turned off. At this time, the first relay valve 380 receives the signal pressure P. , is not occurring (the fourth solenoid valve 346 is off) and the signal pressure P5ots is being generated (the fifth solenoid valve 392 is on), the reverse inhibit valve 420 is moved to the inhibiting position. (In this case, a signal pressure P that is the same pressure as the fourth line pressure P14.5.
), while the signal pressure P, in that combination. ,
and signal pressure P,. 4. reverse inhibit valve 42 based on a combination in which at least one of the occurrence states is different.
Signal to set 0 to non-blocking position (atmospheric pressure in this case)
Therefore, even if an abnormality occurs in the first signal pressure generating means including the fourth solenoid valve 346 or the second signal pressure generating means including the fifth solenoid valve 392, as long as an abnormality does not occur in both of them at the same time. A signal for setting the reverse inhibition valve to the non-blocking position is output from the first relay valve 380 to the reverse inhibit valve 420, so that the vehicle can be reliably driven backward. For example, the electronic control device 460 sends a signal to turn the fourth solenoid valve 346 on and the fifth solenoid valve 392 off in order to switch from B mode, which prevents establishment of reverse gear, to G mode, which does not prevent establishment of reverse gear. If the output is from the actual signal pressure P, due to reasons such as sticking of the valve. , and signal pressure P,. 3. Even if the switch does not switch from the OFF state and ON state to the ON state and OFF state, if it changes from the OFF state and OFF state to the ON state and ON state, that is, the combination of signal pressures to prevent the formation of reverse gear. If one is different, the reverse inhibit valve 420 is set to the non-blocking position, so that the vehicle can be reliably driven backwards.

Although one embodiment of the present invention has been described above based on the drawings,
The present invention can be modified in various ways without departing from its spirit.

For example, in the embodiment described above, the signal pressure P8.4 and the signal pressure P,. 4. was configured to prevent establishment of reverse gear when the gear is in the off state and in the on state,
Other on/off states are also possible.

In short, the signal pressure P for preventing the establishment of reverse gear
,. , and signal pressure P5゜1. It is sufficient that the reverse inhibit valve 420 is set to the non-blocking position when at least one of the combinations of occurrence states is different.

Further, in the above embodiment, the lock-up clutch 36 provided in the fluid coupling 12 has been described, but other types of hydraulically operated clutches may be used.

Furthermore, in the above-described embodiment, two types of first line hydraulic pressure pH and second line hydraulic pressure P12 are used to act on the downstream side hydraulic cylinder 54 and the secondary side hydraulic cylinder 56; The tension of the transmission belt is controlled by applying the hydraulic pressure output from one hydraulic source to the secondary hydraulic cylinder at all times, while the hydraulic oil from that hydraulic source is allowed to flow into the primary hydraulic cylinder or inside the primary hydraulic cylinder. It may also be a hydraulic control device of the type that changes the speed ratio using a speed change control valve device that causes hydraulic oil to flow out.

Further, in the above-mentioned embodiments, a belt-type CVTI 4 has been described, but the present invention may also be applied to a traction-type continuously variable transmission in which power is transmitted via rollers.

Further, in the above-described embodiment, the throttle valve opening detection valve 18
Although a throttle pressure P generated by 0 is used, in a vehicle that does not use a throttle valve, such as a vehicle equipped with a diesel engine, a hydraulic pressure corresponding to the accelerator pedal operation amount may be used. In such a case, for example, the cam 184 of the above-described embodiment may be mechanically associated with the accelerator pedal so as to rotate as the accelerator pedal is depressed.

Also, is the CVT 14 in the above-mentioned embodiment a variable type? IU
In this case, the actual input shaft rotational speed N in was controlled so as to match the target rotational speed N in , but since the speed ratio e = Nout / N in, the actual speed ratio is different from the target speed ratio eも. This is substantially the same even if the speed ratio e is controlled so that e matches.

Further, in the above embodiment, the forward/reverse switching device 16 was provided between the output shaft 38 of the CVT 14 and the intermediate gear device 18, but the forward/reverse switching device 16 was provided between the fluid coupling 12 and the input shaft 30 of the CVT 14. A device 16 may also be provided. Furthermore, the forward/reverse switching device 16 may have two or more forward gears.

Moreover, other types of couplings such as a torque converter, an electromagnetic clutch, a wet type clutch, etc. may be used instead of the fluid coupling 12 of the above-described embodiment.

The above-mentioned embodiment is merely an embodiment of the present invention, and various modifications may be made to the present invention without departing from the spirit thereof.

[Brief explanation of drawings]

FIG. 1 is a detailed circuit diagram of a hydraulic control system for operating the device of FIG. 2. FIG. 2 is a schematic diagram showing a vehicle power transmission device equipped with a hydraulic control device according to an embodiment of the present invention. FIG. 3 is a diagram showing the second pressure regulating valve of FIG. 1 in detail. FIG. 4 is a diagram showing the 111th pressure valve of FIG. 1 in detail. FIG. 5 is a diagram showing the output characteristics of the throttle valve opening detection valve shown in FIG. 1. FIG. 6 is a diagram showing the output characteristics of the speed ratio detection valve shown in FIG. 1. Figure 7 is the second part of Figure 3.
FIG. 3 is a diagram showing output characteristics of a pressure regulating valve. FIG. 8 is a diagram showing ideal characteristics of the second line oil pressure. FIG. 9 is a diagram showing in detail the configuration of the speed change control valve device shown in FIG. 1. Figure 10 shows
The first solenoid valve and the second solenoid valve in the speed change control valve device shown in FIG.
3 is a diagram illustrating the relationship between the operating state of a solenoid valve and the shift state of the CVT shown in FIG. 2. FIG. 11, 12, and 13 are diagrams for explaining the relationship between the speed ratio of the CVT shown in FIG. 2 and the oil pressure value of each part, and FIG. 11 shows the positive torque running state, and FIG. FIG. 13 shows an engine brake running state and a no-load running state. FIG. 14 is a diagram showing the output characteristics of the first pressure regulating valve of FIG. 4 with respect to the primary hydraulic cylinder internal oil pressure or the second line oil pressure. FIG. 15 is a chart showing the relationship between the combination of the operating states of the third solenoid valve and the fourth solenoid valve of FIG. 1 and the operating state of the lock-up clutch. FIG. 16 shows the drive duty ratio DSS of the fifth solenoid valve in FIG. 1 and the signal pressure P3°1. FIG. FIG. 17 is a diagram showing the change characteristics of the duty ratio D3S of the fifth electromagnetic valve and the fourth line oil pressure Pffi4 that is continuously changed in relation to the duty ratio D3S in the hydraulic circuit shown in FIG. FIG. 18 is a diagram illustrating the second line oil pressure that changes in relation to vehicle speed (centrifugal oil pressure). FIG. 19 is a chart showing the relationship between the combinations of operations of the third solenoid valve, the fourth solenoid valve, and the fifth solenoid valve and the control modes selected thereby in the control device of FIG. 2. Figure 20 shows
3 is a flowchart illustrating the operation of the control device of FIG. 2. FIG. Figure 3 16: Forward/forward switching device (automatic transmission) 70: Reverse brake (reverse hydraulic actuator) 2
52: Shift lever (shift operation member) 346: Fourth solenoid valve (first signal pressure generating means) 392: Fifth solenoid valve (second
Signal pressure generation means) 380: First relay valve (relay valve) 420: Reverse inhibit valve

Claims (1)

[Scope of Claims] In an automatic transmission for a vehicle in which engine power is transmitted to drive wheels via a gear device that automatically switches to a reverse gear stage, there is a system that relates to the operation of a shift operation member to a reverse operation position. a hydraulic control circuit for supplying hydraulic pressure to a reverse hydraulic actuator to establish the reverse gear, the circuit being inserted into an oil path through which hydraulic pressure is supplied to the reverse hydraulic actuator, and for establishing the reverse gear. a backward blocking valve positioned in two positions, a blocking position for blocking the reverse gear and a non-blocking position for allowing establishment of the reverse gear; a first signal pressure generating means for generating the first signal pressure; and a second signal pressure. a second signal pressure generating means for generating pressure; and a signal for setting the retraction prevention valve to a blocking position based on a first combination of the generation states of the first signal pressure and the second signal pressure. while outputting a signal for setting the retreat prevention valve to a non-blocking position in a combination in which one of the first signal pressure and second signal pressure in the first combination is the same and the other is different. A hydraulic control device for an automatic transmission for a vehicle, comprising a relay valve.