JPH0369856A - Hydraulic controller of non-stage transmission for vehicle - Google Patents

Abstract

PURPOSE:To maintain slow acceleration and transmission by a method wherein a first valve is positioned at the acceleration side when valve driving hydraulic pressure is not affected by the first valve while a second valve is positioned at the flow rate suppressing side when the hydraulic pressure is not affected by the second valve. CONSTITUTION:If valve driving hydraulic pressure is not supplied to a transmission direction change valve 262 on a transmission speed control valve 264 for some reason such as failure in a valve driving hydraulic pressure generator itself or failure in supply process from the valve driving hydraulic pressure generator, the valve driving hydraulic pressure is not functioned to a first valve 280 of a transmission direction change valve 262 on a second valve 288 of a transmission speed control valve 264 irrespective of operation of a pair of electromagnetic valves 266, 268. Thus the first valve 280 of the transmission direction change valve 262 is positioned at the accelerating side as well as the second valve 288 of the transmission speed control valve 264 is positioned at the flow rate suppressing side. Therefore during malfunction a non-stage transmission is maintained slowly accelerating state.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a hydraulic control system for a continuously variable transmission for a vehicle.

BACKGROUND OF THE INVENTION Continuously variable transmissions for vehicles are known, which are inserted into a power transmission path of a vehicle and whose transmission ratio can be changed steplessly. For example, as described in Japanese Unexamined Patent Publication No. 52-98861, a pair of variable pulleys are provided on the downstream rotating shaft and the secondary rotating shaft, and the power is wound around the pair of variable pulleys. This is a belt-type continuously variable transmission for a vehicle that includes a power transmission belt that transmits the power, and a pair of primary and secondary hydraulic actuators that respectively change the effective diameters of the pair of variable pulleys.

For example, the hydraulic control device for controlling the speed ratio of the continuously variable transmission for vehicles as described above is disclosed in Japanese Patent Application Laid-Open No. 60-95262.
As described in the publication, a spool valve-type transmission direction switching valve that switches the direction of change in the gear ratio of a continuously variable transmission to the speed increasing direction or the decelerating direction, and a spool for controlling the speed of change of the gear ratio. A variable speed control valve in the form of a valve, and a pair of solenoid valves that control the operation of the valves by applying valve driving hydraulic pressure to the valve elements of the valves are provided. The speed change direction switching valve and the speed change speed control valve are respectively switched and operated.

Problems to be Solved by the Invention In general, continuously variable transmissions for vehicles are intended to have a fail-safe function to prevent the engine from over-speeding due to a change in the speed ratio toward the deceleration side while the vehicle is running. In the event of an abnormality, it is desirable to bring the continuously variable transmission into a gradual speed increasing state. For this reason, in the above-mentioned hydraulic control device, when both of the pair of solenoid valves are in the OFF state (non-excited state), the gear ratio of the continuously variable transmission is gradually adjusted to provide an electrical fail-safe. It is configured to change in the speed increasing direction. However, if for some reason the valve drive hydraulic pressure is not supplied to act on the spool valve of the speed change direction switching valve and the spool valve of the speed change speed control valve, the speed change direction changeover valve and Since the spool valve element of the speed change control valve is moved according to the biasing force of a spring or the like, there is an inconvenience that the speed change ratio is preferentially switched to a state in which the speed change ratio is gradually changed in the direction of deceleration.

The present invention has been made against the background of the above circumstances,
The purpose of this is that when an abnormal condition occurs in which the valve drive hydraulic pressure is not supplied for some reason, the continuously variable transmission will gradually increase the speed, regardless of the operating state of the pair of solenoid valves. An object of the present invention is to provide a hydraulic control device for a continuously variable transmission for a vehicle that maintains the same state.

Means for Solving the Problems The gist of the present invention to distantly achieve the above objects is a hydraulic control device for a continuously variable transmission for a vehicle in which the gear ratio is changed steplessly. ) a valve driving hydraulic pressure generating device that generates valve driving hydraulic pressure, and (b) a deceleration side position for changing the speed ratio of the continuously variable transmission in the deceleration direction and a position for changing the speed ratio in the speed increasing direction. The speed change direction switching valve has a first valve element movable to a speed increasing side position, and the first valve element is positioned at the speed increasing side position when the valve driving hydraulic pressure is not applied to the first valve element. and (C) a first electromagnetic valve that switches the first valve element to a deceleration side position by applying the valve driving hydraulic pressure to the first valve element in accordance with an electric signal; (d)
a second valve that is movable between a flow rate suppression side position for suppressing the rate of change in the speed ratio and a flow rate non-suppression side position for not suppressing the rate of change in the speed ratio; 2
a variable speed control valve whose second valve element is positioned at a flow rate suppression side position when the valve element is not actuated; and (e) by causing the valve driving hydraulic pressure to act on the second valve element in accordance with an electric signal. and a second solenoid valve that switches the second valve to the flow rate non-restriction side.

Operation and Effects of the Invention By doing this, it is possible to prevent abnormalities in the valve drive hydraulic pressure generator itself.
Alternatively, if the valve drive hydraulic pressure is not supplied to the shift direction switching valve and the shift speed control valve due to some reason such as an abnormality in the supply process from the valve drive hydraulic pressure generator, regardless of the operation of the pair of solenoid valves, , the valve driving hydraulic pressure is not applied to the first valve element of the speed change direction switching valve and the second valve element of the speed change speed control valve. For this reason, the first valve element of the speed change direction switching valve is positioned at the speed increase side position, and the second valve element of the speed change speed control valve is positioned at the flow rate suppression side position, so that hydraulic pressure for driving the valve is not supplied. In such an abnormal state, the continuously variable transmission is maintained in a gradual speed increasing state.

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 the pump impeller 2 connected to the crankshaft 26 of the engine 10 and the 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 human power shaft 30 via a damper 34;
It includes an engagement-side oil chamber 33 connected to a retention-side oil passage 322, which will be described later, and a release-side oil chamber 35, which is connected to a release-side oil passage 324, which will be described later. The inside of the fluid coupling 12 is always filled with hydraulic oil, and for example, when the vehicle speed exceeds a predetermined value, or when the difference in rotational speed between the pump impeller 28 and the turbine impeller 32 becomes less than a predetermined value, the maintenance side oil is filled. As hydraulic oil is supplied to the chamber 33 and discharged from the disengagement 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 human power 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 shaft. The movable rotating bodies 50 and 52 are protected from the movable rotating bodies 50 and 52.
is moved by the primary side hydraulic cylinder 54 and the secondary side 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. ut/rotational speed Ni, ) 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. usually,
The pressure in the driven one of the hydraulic cylinders 54 and 56 is related to the tension in the 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 pressure 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 in the hydraulic oil that has returned to an oil tank (not shown) through the strainer 76, and also sucks in 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 lock-up clutch pressure oil passage 92. The first line oil pressure pH in the oil passage 80 is regulated. In addition, the first line oil pressure pH is adjusted by the second pressure regulating valve 102 of the pressure reducing valve type.
By reducing the pressure, the second line oil pressure Pf2 in the second line oil passage 82 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
A first land 118, a second land 118 with a larger diameter in order
A land 120 and a third land 122 are formed in this order.

A second line hydraulic pressure P1. A chamber 126 is provided in which the spool valve 110 introduces the second line hydraulic pressure PI! through the throttle 124 as a feedback pressure. , , are biased in the valve closing direction. Also, spool valve 1
A chamber 130 is provided on the end face side of the first land 118 of No. 10, through which a speed specific pressure Pe (described later) is guided through a throttle 128, and the spool valve element 110 is biased in the valve closing direction by the speed specific pressure Pe. It is supposed to be done. Second pressure regulating valve 102
Inside, the urging force of the return spring 114 in the valve opening direction is applied to the spool valve 1 via the spring seat 112.
It is given to 10. Further, a land 117 and a land 119 having a slightly larger diameter are formed on the plunger 116, and a chamber 132 for applying a throttle pressure Pth, which will be described later, is provided on the end surface side of the land 117, and The valve element 110 is biased in the valve opening direction by this throttle pressure P.

Therefore, the pressure receiving area of the first land 118 is A1, and the pressure receiving area of the second land 118 is A1.
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 reduces the second line oil pressure by reducing the first line oil pressure Pffi, which is a relatively high oil pressure as described above. Pj2. is generated as shown in FIG.

p zz z =<to a・Ptt, +W-At
・Pe)/(Az-At)In addition, the above spool valve 1
Between the first land 118 and the second land 120 of No. 10, a signal pressure P5°3.
A chamber 136 is provided in which the signal pressure P is introduced, and the spool valve 11O receives the signal pressure P. 4. When the valve is biased in the valve closing direction, the second line hydraulic pressure Plz is reduced depending on the magnitude of the bias. Further, the plunger 11
Between land 117 and land 119 of No. 6, the first
Control pressure P, via relay valve 380, second relay valve 440, which will be described later, and throttle 135. ,.

A chamber 133 is provided in which the second line pressure P2□ is increased in accordance with the signal pressure P5oLs. 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 connects a port 150a communicating with the first line oil line 80 and a drain boat 150.
b or 150c, and a first land 152 has a first land 152 on its end face as a feedback pressure.
A chamber 153 is provided to act on the line hydraulic pressure P insufficient through a throttle 151, and this first line hydraulic pressure P
, the spool valve element 140 is biased in the valve opening direction. A chamber 156 for introducing the throttle pressure Pth is provided between the first land 154 and the second land 155 of the first plunger 146, which is provided coaxially with the spool valve element 140. 155 and the second plunger 148 is a primary hydraulic cylinder 54.
A chamber 157 is provided for guiding the hydraulic pressure pin in the second plunger 14 through the branch oil passage 305.
8 has a chamber 15 for guiding the second line hydraulic pressure Pf.
8 is provided. 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 set as As, and the pressure receiving area of the first land 152 of the first plunger 146 is 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. is balanced, and the first line oil pressure Pl is regulated.

PA, = ((ptn Or Pj! z) ・At +Pth(
^b AT) +W) / As・ ・ ・ ・(2
) In the first pressure regulating valve 100, the negative side hydraulic cylinder 5
4 internal hydraulic pressure P is higher than the second line hydraulic pressure PI2 (in steady state, Plz = secondary hydraulic cylinder 56 internal hydraulic pressure P, t), the gap between the first plunger 146 and the second plunger 148 Separated from the above-next side hydraulic cylinder 54
The thrust force due to the internal hydraulic pressure p in acts on the spool valve element 140 in the valve closing direction, but the internal hydraulic pressure p in the -next side hydraulic cylinder 54
in is lower than the second line oil pressure P12, the first
Since the plunger 146 and the second plunger 148 are in contact with each other, the thrust by the second line hydraulic pressure Plt acting on the end face of the second plunger 148 is applied to the spool valve 1.
40 in the valve closing direction. That is, the second plunger 148, which receives the hydraulic pressure PIfl in the next-side hydraulic cylinder 54 and the second line hydraulic pressure Pffi, applies an acting force based on the higher of these hydraulic pressures in the direction of closing the spool valve element 140. Let it work. In addition, spool valve 14
A chamber 160 provided between the first land 152 and the second land 159 at G4 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 182. 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
The first line hydraulic pressure PZ is positioned at a position where the thrust from PZ and the thrust due to the first line hydraulic pH are balanced.
, and generates a throttle pressure PLb corresponding to the actual throttle valve opening θth. FIG. 5 shows the relationship between the throttle pressure Pth and the actual throttle valve opening θ.
Throttle pressure P or the first pressure regulating valve 100 through the 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. By receiving the urging force from the spring 194 correspondingly transmitting the urging force and by being positioned at a position where the thrusts of both are balanced by receiving the second line oil pressure Pi, the discharge flow rate to the drain is reduced. It is equipped with a spool valve 19B that changes the spool valve. 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 19B
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 passage 82 through the
While e is limited to a value equal to or higher than the second line oil pressure Pf2, the second pressure regulating valve 102, which operates according to the above equation (1), increases the second line oil pressure Pl□ as the speed specific pressure Pe increases. reduce Therefore, when the speed specific pressure Pe increases to a predetermined value and becomes equal to the second line oil pressure Pff2, both are saturated and constant thereafter.

FIG. 7 shows the output characteristics of the second line oil pressure Pf, which is regulated in the second pressure regulating valve 102 in relation to the 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 controls the optimum third line oil pressure Pf for operating the reverse brake 70 and the forward clutch 72 of the forward/reverse switching device 16.

It is something that generates. The third pressure regulating valve 220 includes a spool valve element 222 that opens and closes between the first line oil passage 80 and the third line oil passage 88, a spring seat 224, a return spring 226, and a plunger 228. The first land 230 and the second land of the spool valve 222
A chamber 23 is provided between the land 232 and the third line hydraulic pressure Pf3 introduced through a throttle 234 as a feedback pressure.
6 is provided so that the spool valve element 222 is urged in the valve closing direction by the third line oil pressure Pf3. Further, a chamber 24 is provided on the first land 230 side of the spool valve element 222 to which the speed specific pressure Pe is introduced via a throttle 238.
0 is provided, and the spool valve 222 has a speed specific pressure P
e, the valve is biased toward the valve closing direction. Third
Inside the 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. Also, plunger 2
Chamber 2 for applying throttle pressure P to the end face of 28
42 is provided, and the spool valve element 222 is urged in the valve opening direction by this throttle pressure F'th. Additionally, the first land 244 of the plunger 228
A chamber 248 is provided between the land 246 and the second land 246, which has a smaller diameter, for guiding the third line hydraulic pressure Pffi3 only during reverse movement.
is provided. Therefore, the third line oil pressure Pf is regulated to an optimal value based on the speed specific pressure Pe and the throttle pressure Pth using an equation similar to equation (1) above. This optimum value is a value necessary and sufficient to ensure that torque can be transmitted without slipping in the forward clutch 72 or the reverse brake 70. Furthermore, when traveling in reverse, the third line hydraulic pressure P13 is guided into the chamber 248, so the spool valve 2
22 in the valve opening direction is increased, and the third line oil pressure PI3 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 Pffi3 regulated as described above is
A manual valve 250 selectively supplies the forward clutch 72 or the reverse brake 70. That is, the manual valve 250 includes a spool valve 254 that is moved in conjunction with the operation of the vehicle's shift lever 252, and is configured to move forward ranges such as L (low), S (second), and D (drive) ranges. When the third line hydraulic pressure P13 is being operated, the third line oil pressure P13 is exclusively output from the output port 258 and supplied to the forward clutch 72, and at the same time, the oil is allowed to drain from the reverse brake 70 to the drain. On the other hand, when the R (reverse) range is being operated, the third line oil pressure P13 is output to the output port 25.
6 to port 422a of reverse inhibit valve 420
and 422b, and further supplies the oil to the reverse brake 70 through the reverse inhibit valve 420, and at the same time allows oil to drain from the forward clutch 72, and is operated to N (neutral) and P (parking) ranges. In this case, drainage of oil from both the forward clutch 72 and the reverse brake 70 is allowed. Incidentally, the accumulators 342 and 3-40 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 adjusts the transient inflow flow rate by closing the throttle 212 in response to an increase in the hydraulic pressure in the hydraulic cylinder of the forward clutch 72.

The first line oil pressure Pffi regulated by the first pressure regulating valve 100 and the second line oil pressure Pf 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 PI! for driving the speed change direction switching valve 262 and the flow rate control valve 264! ,
, is generated by the fourth pressure regulating valve 170 based on the first line oil pressure Pit, and is guided through 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.

A chamber 176 is provided between the first land 173 and the second land 174 of the spool valve element 171 to introduce the fourth line hydraulic pressure P14 to act as feedback pressure, while the spring 172 of the spool valve element 171
On the end surface side of the plunger 175 that comes into contact with the side end portion, a signal pressure P3°3. which will be described later is applied in the valve opening direction. A chamber 177 for introducing the spring is provided, 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 element 171 has a biasing force in the valve-closing direction based on the feedback pressure corresponding to the fourth line oil pressure Pf, a biasing force in the valve-opening direction by the spring 172, and As a result of being operated so that the biasing force in the valve opening direction based on the signal pressure P5°t4 is balanced, the fourth line oil pressure Pf.

is regulated to a value corresponding to the magnitude of the signal pressure P5ots, which will be described later.

As shown in detail in FIG. 9, the speed change direction switching valve 262 is
A second connecting oil passage 2 which is a spool valve controlled by the first electromagnetic valve 266 and includes a drain port 278a that communicates with the drain, a first connecting oil passage 270, and a first throttle 271.
72, and the third connecting oil passage 274, respectively, are connected to the ports 278b, 278d, and 278f, and the port 2 to which the first line hydraulic pressure PlI is supplied through the throttle 276.
78c, a port 278e to which the first line hydraulic pressure Pffi+ is supplied, a port 278g to which the second line hydraulic pressure Pf2 is supplied, and a deceleration side position (on side position) which is one end of the movement stroke (upper end in the figure). The other end of the travel stroke (
A spool valve element 280 is slidably disposed between the spool valve element 280 and the speed increasing side position (off side position), which is the lower end of the drawing, and a spring 282 that biases the spool valve element 280 toward the speed increasing side position. It is equipped with The above spool valve 28
0 has four lands 279a, 279b, 279c,
279d is provided. The end surface of the spool valve 280 on the spring 282 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 P14 regulated by the fourth pressure regulating valve 170 is applied to the end surface on the lower end side of the spool valve element 280. When the electromagnetic valve 266 is in the OFF state, that is, in the open state, the pressure downstream of the throttle 284 is exhausted and the fourth line oil pressure P14 is not applied. When the first solenoid valve 266 is in the ON side in the figure, the shift direction switching valve 262 is also in the ON side in the figure, and when the first solenoid valve 266 is in the OFF position in the figure, the shift direction switching valve 262 is in the ON side in the figure. The valve 262 is also in the position shown on the OFF side in the figure.

Therefore, during the period when the first solenoid valve 266 is in the on state,
The spool valve element 280 is located at the deceleration side position and the port 27 is located between the drain port 278a and the port 278b.
8e and port 278r are opened, and ports 278b and 2780 and port 278d are opened.
and 278e, and between ports 278f and 278g, respectively, but during the period when the first solenoid valve 266 is in the OFF state, the spool valve element 280 is positioned at the speed increasing side position and the opposite situation is established. It will be in a switching state.

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 has a port 286a that communicates with the downstream hydraulic cylinder 54 via the primary oil passage 300 and the second connecting oil passage 272, the first connecting oil passage 270, and the third connecting oil passage 274. ports 286b and 286d, which communicate with each other, and the secondary oil passage 30.
Port 2 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, the end face of the spool valve element 288 on the spring 290 side is open to the atmosphere, so no hydraulic pressure is applied thereto.

However, the lower end surface of the spool valve 288 has a second
When the solenoid valve 268 is in the ON state, that is, in the closed state, the fourth line oil pressure P°C4 regulated by the fourth pressure regulating valve 170 is applied, and in the OFF state, that is, in the open state, the pressure downstream of the throttle 292 is exhausted. The fourth line oil pressure Pj24 is not applied. The second solenoid valve 268 is turned on as shown in the diagram.
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 between the ports 286a and 286b, the spool valve element 288 is placed between the ports 286a and 286b. and 286d, 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 operates when the first line hydraulic pressure pH is supplied to the secondary hydraulic cylinder 56 during deceleration shifting or engine braking when the secondary hydraulic cylinder 56 is set to a relatively high pressure side. A large amount of the hydraulic oil in the secondary hydraulic cylinder 56 flows out to the second line oil passage 82, and the hydraulic pressure P in the secondary hydraulic cylinder 56 decreases. This is to prevent ut (=Pj2+) from decreasing, and to ensure that hydraulic oil is supplied from the second line hydraulic pressure Pf2 into the secondary hydraulic cylinder 56 during slow deceleration shifting. 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 Pout is compensated for through the check valve 298. The check valve 298 includes a valve seat 299 having a flat seating surface, a valve 301 having a flat contacting surface that comes into contact with the seating surface, and the valve 301.
The spring 303 urges the valve toward the valve seat 299, and is opened 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 at the time of slow speed increase, and the aperture 276 determines the speed at the time of rapid increase.

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 flows into the port 278e, the port 27
8f, third connection oil passage 274, port 286d, port 2
86c.

The hydraulic oil in the secondary hydraulic cylinder 54 flows through the secondary oil passage 302 into the secondary hydraulic cylinder 56, while the hydraulic oil in the secondary hydraulic cylinder 54 flows through the secondary oil passage 300, port 286a, port 286
b, is discharged to the drain through the first connection oil passage 270, port 278b, and drain port 278a. This results in
As shown in FIG. 10(a), the speed ratio e is changed to a higher speed 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 flows through the throttle 276 and the port 27.
8c.

Port 278b, first connection oil passage 270, port 286b
, boat 286a, flows into the primary side hydraulic cylinder 54 through the downstream side oil passage 300, and the port 2
78e, the port 278d, the second connection oil passage 272, and the downstream oil passage 300 to flow into the primary hydraulic cylinder 54, while the hydraulic oil in the secondary hydraulic cylinder 56 flows through the secondary oil passage 302 and the port 286c, boat 286d, third connection oilway 274, port 278r, and port 278g and are discharged to the second line oilway 82. This results in
As shown in (f) of FIG. 1O, the speed ratio e is quickly changed in the speed increasing direction.

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. 1O shows this state.

Here, the first line oil pressure Pl in the CVT 14 is:
When running with positive drive (when drive torque T is positive), the desired oil pressure values are as shown in Figure 11, and when running with engine braking (when drive torque T is negative), oil pressure values as shown in Figure 12 are desired. A hydraulic value such as this 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.
Hydraulic pressure PL, ut in 6, P during engine braking driving as shown in Fig. 12. ut>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
It is desirable that the line oil pressure PlI is regulated to a value obtained by adding a necessary and sufficient margin oil pressure α to the above Pi7.

However, it is impossible to adjust the first line oil pressure pH 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, and a second line oil pressure Pj2. The biasing force based on the higher oil pressure is transmitted to the spool valve element 140 of the first pressure regulating valve 100. As a result, for example, during no-load running, as shown in FIG. It is controlled to a value obtained by adding a margin value α to the higher oil pressure value of Pi, . As a result, the first line oil pressure P
L is controlled to a necessary and sufficient value to minimize power loss. Incidentally, the first line oil pressure Pj shown by the broken line in FIG. 13! , ' are the case where the second plunger 148 is not provided, and an unnecessarily large excess oil pressure is generated in a range where the speed ratio e is large.

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 it is clear from (2) 2. As such, the first line oil pressure Pffi is increased in relation to the throttle pressure PLh. Pressure receiving area of each part of the first pressure regulating valve 100 and return spring 14
The urging force of No. 4 is set in this way. At this time, the first line oil pressure pH regulated by the first pressure regulating valve 100 is P8. , or P
. It increases as uL and throttle pressure P increase,
It is designed to be saturated at a maximum value corresponding to the throttle pressure P. As a result, the speed ratio e reaches the maximum value, and the hydraulic pressure P in the primary hydraulic cylinder 54 is maintained in a state where the decrease in groove width of the primary variable pulley 40 is mechanically prevented.
Even if .

Returning to FIG. 1, the operating water 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 cL. 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 in accordance with the throttle pressure P. Generate up clutch oil pressure Pet.

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 lock-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 has a signal pressure P that is the same as the fourth line oil pressure P14 of the fourth line oil passage 370 in its ON state. 1. 1. Generate. Fourth solenoid valve 346
In its OFF state, the pressure downstream of the throttle 344 is exhausted to the drain, and in its ON state, the fourth line hydraulic pressure P
I1. Signal pressure P, which is the same pressure as . , occurs. Fifth
The solenoid valve 392 discharges pressure downstream of the throttle 394 in its off state, and discharges pressure in the fourth line oil pressure P in its on state.
The same signal pressure P 1ots as in 14 is generated. In this embodiment, each of the signal pressures P 5oL3, P 56L4, P
The combination of 5oLs performs multiple types of control, including 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, and reverse inhibit control. It is supposed to be done.

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 PeL.
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), the lock-up clutch hydraulic pressure Pcl is supplied to ports 321C and 321d.
, bow) 321b and drain port 321a, bow) 32
1e and port 321f to release the lock-up clutch 36 (off side in the figure), the port 321
c and port 32 l b, port 321d and port 32
1e, a spool valve 326 that communicates the boat 321f and the drain port 321g, and a spring 328 that biases the spool valve 326 toward the release side (off side). Lower end surface side of spool valve 326 (non-spring 32
8 side) is a signal pressure P8°3. which is generated when the third solenoid valve 330 is in the on state. A chamber 332 into which is introduced is provided.

The lock-up clutch quick release valve 400 is a two-position operating type two spool valve, and includes a port 402a communicating with the clutch pressure oil passage 92 via a throttle 401, and a release side oil passage 32.
A port 402b communicates with port 402B, and a port 402C communicates with port 321b of lock-up clutch control valve 320.
, boat 321f of lock-up clutch control valve 320
port 402e that communicates with the engagement side oil passage 322, lock-up clutch control valve 320
The port 402r communicates with the bow) 321d, and the port 402b and the bow) 402c in normal operation (off side in the figure) communicate with the port 402b.
, port 402e and port 402f are communicated with each other, and at the time of sudden release (on side in the figure), the boat 402a and port 402
b, a spool valve element 406 that communicates the ports 402d and 402e, and a spring 408 that biases the spool valve element 406 toward the quick release side position. A signal pressure P5ots generated when the fourth electromagnetic 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, when the third solenoid valve 330 is turned on while the fourth solenoid valve 346 is turned off, the spool valve 326 is placed in the on-side position shown in the figure, and the lock-up clutch 36 is engaged. Because a third oil passage is formed for
402e, and the fluid coupling 1 through the engagement side oil passage 322.
2 and flows out from the fluid coupling 12 is drained from the port 321a through the release side oil passage 324, port 402b, port 402C, bow) 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 first oil passage for releasing the lock-up clutch 36 is formed, so that the hydraulic oil in the lock-up clutch pressure oil passage 92 is drained.
321c, port 321b1 port 402C1 baud) 4
02b, and the fluid coupling 12 through the release side oil passage 324.
The hydraulic oil flowing out from the fluid coupling 12 is supplied to the engagement side oil passage 322, port 402e, port 402f, port 321d, port 402e, and oil cooler 33.
It is drained after 9. 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 flows through ports 402a, 402b,
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 402 e, baud) 402d, port 321
The oil is drained through the oil cooler 339, the port 402e, 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 mode and the second release mode is selected, engine stall is prevented by switching to the other mode, and the vehicle is 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, if a sudden release is required such as in the case of sudden vehicle braking, 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,
port 402e, bo) 402d.

It is drained from port 321g via bow 1-321f. As a result, the oil cooler 339 with large flow resistance
Since the water is drained without passing through, the lock-up clutch 36 is immediately released. FIG. 15 shows the mode of the lock-up clutch 36, the third solenoid valve 330, and the fourth solenoid valve.
The relationship with the operating state of the electromagnetic valve 346 is shown.

In addition, the oil cooler 339 is
The hydraulic oil that is returned to an oil tank (not shown) is relieved by a cooler oil pressure control valve 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 while 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 maintenance.

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 bow 1-44 of the second relay valve 440.
port 382a communicating with port 2c, port 382b to which signal pressure P5ols is supplied, chamber 1 of second pressure regulating valve 102
Port 382C1 and drain port 382d, which communicate with 36 and reverse inhibit valve 420, communicate with port 382a and port 382b, and port 382c and drain port 382d in the on side state of the figure, and drain the port 328a in the off side state of the figure. A chamber provided on the non-spring side of the spool valve 384 includes a spool valve 384 that communicates the port 382b and the bow 382c, and a spring 386 that biases the spool valve 384 toward the off-side state. 388
When the signal pressure P5oL4 is not applied to the signal pressure P, the spool valve 384 is in the OFF position. ,
.

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 P3° is applied to the chamber 388, the spool valve 384
is set to the on side, and the signal pressure P5ets is set to the second position.
It is supplied to port 442C of 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 is connected to the chamber 1 of the second iPII pressure valve 102.
Ports 442b and 442c that communicate with 33 through a throttle 443 and are always in communication with each other, a port 442d that communicates with the accumulator 37.2 and the fourth pressure regulating valve 170, and a drain port 442e, in the on-side state shown in the figure. a spool valve 444 that communicates the port 442d with the drain port 442e and blocks the connection between the port 442d and the drain port 442e in the off-side state shown in the figure;
A signal pressure P 5ot is provided in a chamber 448 provided on the non-spring side of the spool valve 444.
When s is not applied, the spool valve 444 is in the OFF position, and when the signal pressure P5oL3 is applied to the chamber 448, the spool valve 444 is in the ON position. This allows ports 442c and 442
Signal pressure P5°, which is supplied to the chamber 133 of the 211th pressure valve 102 through b.

However, when the spool valve element 444 is switched from the on to off position, the water is branched and also supplied to the accumulator 372 and the chamber 177 of the fourth pressure regulating valve 170 . 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 solenoid valve 392 is driven on duty, a signal pressure P5.3. As shown in FIG. I6, the oil pressure is changed in accordance with the duty ratio DsS. That is,
The throttle 394 and the fifth solenoid valve 392 have a signal pressure P. 4
．． It functions as a signal pressure generating means to generate. The signal pressure pso, which is changed in accordance with the drive duty ratio DsS of the fifth solenoid valve 392, is controlled when the first relay valve 380 is turned on and the second relay valve 440 is turned off for back pressure control. When the condition is established, the oil is supplied to the accumulator 372 and the fourth pressure regulating valve 170 via the oil passage 348.

Here, the back pressure control of the accumulators 340 and 342 is as follows:
This is done to reduce the shift shock (locking shock) at the time of N-)D shift or N-+R shift, 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 P1m supplied to the back pressure boat 366 of the accumulator 342 for the forward clutch 72 and the back pressure boat 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 hydraulic pressure PEa is regulated to a pressure corresponding to the signal pressure P5ots.

That is, while the signal pressure P 5oLs is being supplied to the chamber 177 of the fourth pressure regulating valve 170 through the first relay valve 380 and the second relay valve 440 during the N→D shift and the N−+R shift, as shown in FIG. As shown, the fourth line oil pressure Pf is equal to the duty ratio Dis of the fifth solenoid valve 392.
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 (engagement shock). Also,
The oil pressure in the forward clutch 72 is the third line oil pressure PI! ,
, the signal pressure P being supplied to the fourth pressure regulating valve 170. When t5 is shut off by the second relay valve 440 and the inside of the chamber 177 is released to the atmosphere, the fourth line oil pressure PZ4 becomes a relatively low level of about 4 kg/cm2 corresponding to the biasing force of the spring 172 in the valve opening direction. Controlled to a constant pressure. The fourth line hydraulic pressure P14 regulated to a constant pressure is used exclusively as a driving hydraulic pressure (pilot hydraulic 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 17
0 functions as a valve drive oil pressure generating device that generates valve drive oil 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 P related to the duty drive frequency of the fifth solenoid valve 392. 1. 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 Pit. 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 Pf2 is lowered. That is, the signal pressure P, through the boats 382b and 382c of the first relay valve 380. , 5 (= P ffi
4) is the 28th)! When supplied to the chamber 136 of the seat valve 102, the second line oil pressure P12 is regulated according to the following equation (3), and as shown by the dashed line in FIG. be lowered in comparison. 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 a reduction control of the second line oil pressure Pf2 is also performed during reverse prohibition control, which will be described later, or when the shift lever 252 is operated to the N range. Note that the fourth solenoid valve 346
is turned on or the fifth solenoid valve 392 is turned off, the second line oil pressure Pffi2 becomes the same as (1) above.
controlled as usual according to Eq.

P2□=[A4・P+(A5-A4)・P5゜15+
AI'P-(Am Al)・P-015)/(E3 42)・・(3) The reverse inhibit valve 420, which is provided to prohibit reverse during forward running, is set when the manual valve 250 is in the R range. The boats 422a and 422b to which the third line hydraulic pressure Pf3 is supplied from the output boat 256 when the boat is in the position, the sliding boat 422c which communicates with the hydraulic cylinder of the reverse brake 70 via the oil passage 423, and the drain boat 422d are moved. The first point is the upper end of the stroke.
position (non-blocking position) and the second position which is the lower end (blocking position)
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 a signal pressure P soL'i is applied to a chamber 435 provided on the end surface side of the first land 430 through the first relay valve 380 in the OFF state. It is now being supplied. 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. While the line hydraulic pressure P13 is applied to the chamber 438 between the spool valve element 424 and the plunger 428, the hydraulic pressure in the reverse brake 70 is applied to the plunger 428.
The chamber 439 provided on the end face of
, is constantly supplied. In addition, this plunger 428
The pressure-receiving area on which the third line oil pressure Plz acts is defined as the pressure-receiving area difference between the first land 430 and the second land 432 of the spool valve element 424 that receive the oil pressure in the chamber 436, and the path.

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 P5° is greater than the thrust in the valve opening direction based on the internal oil pressure and the third line oil pressure P13.

When the thrust in the valve closing direction based on the third line oil pressure Pffi and
The boat 422b and the boat 422C are moved against the biasing force of the boat 422C, and the boat 422C and the drain port 422d are made to communicate with each other, so that the reverse brake 70 is released to the drain, and the boat 422b and the boat 422C are moved to communicate with each other. Establishment of the reverse gear of the switching device 16 is prevented. That is, when the fifth solenoid valve 392 is turned on and the signal pressure P 1ots is generated when the fourth solenoid valve 346 is in the off state,
Establishment of the reverse gear of the forward/reverse switching device 16 is prevented on the condition that the shift lever 252 is operated to the R range. However, the reverse inhibit valve 420 cannot be operated when the fourth solenoid valve 346 is turned on, when the fifth solenoid valve 392 is turned off, or when the shift lever 252 is operated to a range other than the R range. When any one of these is performed, the spool valve element 444 is moved according to the biasing force of the spring 426, and the reverse brake 70 is brought into communication with the boat 256 of the manual valve 250. Therefore, the electronic control device 46 described below
0, the fourth solenoid valve 346 is in the off state and the fifth solenoid valve 392 is in the on state, and the shift lever 25
2 is erroneously activated from the D range to the R range passing through the N range, the engagement of the reverse brake 70 is prevented 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 P 5oLs is applied to the chamber 13 of the second pressure regulating valve 102 through the first relay valve 380.
6, the second line oil pressure Pf is the signal pressure P.
The predetermined pressure is lowered in accordance with 5 ots. As a result, in the N range, the clamping force on the transmission belt 44 is made as low as possible within a range that does not cause slippage, and in addition to reducing the noise level of the heald, the durability of the transmission belt 44 is increased.

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 P. 1
．． is supplied to the chamber 133 of the second pressure regulating valve 102 through the 11th J relay valve 380 and the second relay valve 440,
The second line oil pressure P12 is increased by a predetermined amount in response to the signal pressure P5oL5. As a result, accumulator back pressure can be controlled during sudden deceleration changes such as during sudden braking, when sudden deceleration changes are made by operating the shift lever 252 from the D range to the L range, and when the shift lever 252 is operated from the N range to the D or R range. At the time, 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 engaged state of the lock amplifier clutch 36 of the fluid coupling 12, the increase or decrease control of the second line oil pressure Pffi, etc. are controlled. The electronic control unit 460 includes a CPU, R
A.M.

It is equipped with a so-called microcomputer consisting of a ROM, etc., which includes a vehicle speed sensor 462 that detects the rotational speed of the drive wheels 24, a human power shaft 30 of the CVT 14, and an output shaft 38 of the CVT 14.
Input shaft rotation sensor 464 that detects the rotation speed of each
and an output shaft rotation sensor 466, a throttle valve opening sensor 468 that detects the opening of the 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 an operating position sensor 470 that detects the operating position of the shift lever 252. A signal representing the vehicle speed ■, a signal representing the input shaft rotation speed N in, and an output shaft rotation speed N are output from the brake switch 472 for detecting the operation, and the engine rotation sensor 474 for detecting the rotation speed N of the engine 10. . A signal representing t, a signal representing the throttle valve opening degree θ, a signal representing the operation position Ps of the shift lever 252, a signal representing the brake operation, and a signal representing the engine rotation speed N are supplied. The CPU in the electronic control unit 460 processes input signals according to a program stored in advance in the ROM while utilizing the temporary storage function of the RAM, and processes the input signals in accordance with a program stored in advance in the ROM, and
Second solenoid valve 268, third solenoid valve 330, fourth solenoid valve 34
6. Output a signal for driving the fifth solenoid valve 392.

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, and input signals based on the read signals. The rotational speed N of the shaft 30 is the rotational speed N of the output shaft 3. ut,
The speed ratio e, vehicle speed V, etc. of CvT14 are calculated, and according to the input signal conditions, lock-up clutch engagement control and sudden release control of lock-up clutch 36, CVTI4
Shift 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. 2O. Step S
In 1, input signals etc. from each sensor are read, and based on the read signals, vehicle speed ■,
The rotational speed N in of the human power shaft 30 and the rotational speed N of the output shaft 38. ut, throttle valve opening θ, shift operation position P
3. Engine rotation speed N is calculated. Step S2
In , the predetermined relationship (Nifi” = f
(θi, v.

P5)], the target rotational speed N in of the input shaft 30 is determined based on the shift operation position PP, the throttle valve opening θ, and the vehicle speed V. 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 following step S3, the control deviation ΔN, (=Ni, ``-Ni,) between the actual rotational speed N in and the target rotational speed N i of the input shaft 30 of the CVT 14 is determined. Then, in step S4, one of the plurality of shift modes shown in FIG. 10 is selected based on the magnitude of the control deviation ΔNi,1 determined in step S3. This selection method is based on, for example, the control deviation Δ out of the shaded area corresponding to multiple types of shift modes shown in FIG. 1O.
A shift mode corresponding to the region including N i 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, if the initial control deviation ΔN i n is 250 r
When the shift mode (B) is selected at pm, if the control deviation ΔN in decreases to 14 Orpm and is included in the overlap between the shift mode (B) and the shift mode (C), Shift mode (b) is selected.

Furthermore, if the control deviation ΔN i n is included in the overlap between the shift mode (B) and the shift mode (C) from the state where the shift mode (C) is selected, the shift mode (C) is selected. It is chosen.

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 DSZ (%) 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 of the second electromagnetic valve 268 is calculated according to the following equation (5). .

D-z=1・ΔNi, -...(4) D-2=
K2・ΔNi, ...(5) However, K+, Kz
is a constant.

Here, the reason why two types of equations (4) and (5) are used when determining the duty ratio Ds2 of the second electromagnetic 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. It's for a reason.

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 ILz 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 such that it is in the on state for T, -D, 2/100 hours out of a certain period (cycle) TD, and for T[l · (1-D,!/100) hours is executed periodically so that the is turned off. Here, the duty ratio D8□ 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 flow rate control valve 264 is driven (step 512) using the duty ratio D6□ determined in step S7 or S8, so that the target rotational speed N in
Feedback control is executed to match the actual rotational speed N i n with the actual rotational speed N i n .

In step S9, each control executed by the third solenoid valve 330 and the fourth solenoid valve 346, that is, 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. 19, and the fifth solenoid valve 392 is further turned on. state and decide. As a result, the second line oil pressure PR2 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) an/
If it is determined that the vehicle is traveling forward beyond a predetermined value of approximately h, the third solenoid valve 33 is
0, the fourth solenoid valve 346, and the fifth solenoid valve 392 operate in the same state. For this reason, reverse inhibit valve 4
Since the signal pressure P 5ols continues to be supplied to the chamber 435 of the manual pulp 250, if the shift lever 252 is mistakenly operated to the N range, the third line oil pressure Pl' is transferred from the boat 256 of the manual pulp 250 to the chamber 436 of the reverse inhibit valve 420. r is supplied, the reverse inhibit valve 420 is operated to the blocking position, and establishment of the reverse gear is prevented.

Furthermore, when the throttle opening degree θ and vehicle speed V 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 and the fourth solenoid valve 346 are determined to be 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 10100)/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 330 and the off state of the fourth solenoid valve 346, the fifth solenoid valve is determined to be on state. As a result, the second line oil pressure Pf2 is reduced by a predetermined value in order to prevent the transmission belt 44 from becoming excessively tensioned due to the centrifugal oil pressure.

Furthermore, when the lock amplifier clutch 36 is in the engaged state, if the vehicle speed V and the throttle opening θ go out of the retention range shown in the diagram in the D range, or if the operation is performed in the N range, as shown in FIG. the first release mode or the second release mode, i.e. A or H in FIG.
The third solenoid valve 330 and the fourth solenoid valve 346 are both determined to be in the on state or off state so as to be in the mode.

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 Pf 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 N 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""1Nout ip'Npel"
・(6) Nd=lNout−Npcl --
・C't) Here, the above N c+ u t is CVT14
, N□ is the rotational speed of the carrier 60 of the forward/reverse switching device 16, and ip is the gear ratio of the forward/reverse switching device 16 when moving backward. 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, 1p is N when the reverse brake 70 is fully engaged. , and N pc according to the following equation (9).

Npc=C/V ・ ・ ・(8) 1 p
=N out/N pc (9) However, C is a constant.

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

This determination reference value C9 is a value for determining whether engagement of the forward clutch 72 or the reverse brake 70 has been completed. The actual rotational speed difference Nd is the judgment reference value C, 4
If it is determined that the actual rotational speed difference Nd is not larger than the judgment reference value CN, the back pressure control is not executed because the engagement is completed. However, if it is determined that the actual rotational speed difference Nd is larger than the judgment reference value The off state of the 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, and the accumulator back pressure control mode shown in F in FIG. 19 is selected. Fifth solenoid valve 3 at this time
The duty ratio of 92 is varied according to a pre-stored time function. As a result, when the N-+D shift operation or the N→R shift operation is performed, the accumulator 342
Alternatively, the back pressure at 340 is changed slowly so that the forward clutch 72 or the reverse brake 70 is smoothly engaged.

When the brake switch 472 is on in the forward range and the release conditions for the lock-up clutch 36 are met, 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 once, 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 or the throttle opening θ is out of the engagement range of the lock-up clutch 36 in the engagement diagram and the lock-up clutch 36 is in either the first release mode or the second release mode, the fluid coupling 12 is Rotation difference between input and output shafts (=N, -Ni,
) 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. In addition, the third solenoid valve 330 is turned on so that the vehicle speed 2 or the throttle opening θ is within the engagement range of the lock-up clutch 36 shown in the engagement diagram, and the engagement mode shown in FIG. 15 is achieved. 4th solenoid valve 3
46 is in the off state, the lock-up clutch 3 is activated based on the fact that the rotational difference (=N, -N, .
If it is determined that the lock-up clutch control valve 6 is released, the lock-up clutch control valve 320 is actually in the off state and the lock-up clutch quick release valve 400 is in the on state and is in the quick release mode, so the other one is released. By selecting the mode, cooling of the hydraulic oil is ensured.

As described above, after the control mode is selected in step S9, it is determined in step 310 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 311.
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 312, 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.

According to the hydraulic control circuit of this embodiment, as shown in detail in FIG. 1, if some abnormality occurs in the fourth pressure regulating valve 170 itself, which functions as a hydraulic pressure generating means for driving the valve, such as sticking of the spool valve element 171. , or an abnormality occurs in the oil passage 370 which is the supply path from the fourth pressure regulating valve 170 to the first solenoid valve 266 and the second solenoid valve 268, and the Even when valve driving oil pressure is not supplied, the shift direction opening switching valve 26 is
The second spool valve element 280 is positioned at the speed increasing side position according to the urging force of the spring 282, and the spool valve element 288 of the flow rate control valve 264 is positioned at the flow rate suppressing side position according to the urging force of the spring 290. Therefore, not only when the first solenoid valve 266 and the second solenoid valve 268 are both in the OFF state, but also in the above-mentioned abnormal state, the CVT 14 is maintained in the gradual speed increasing state, so that the gradual speed increase is maintained. Compared to the conventional case where a deceleration shift is selected, over-speeding of the engine during high-speed driving is prevented.

Further, according to this embodiment, as shown in FIG.
The gradual speed increase and slow speed change states of T14 are selected by simply switching the first solenoid valve 266 between the on state and the off state while the second solenoid valve 268 remains off. Therefore, in the speed ratio feedback control described above, the second solenoid valve 268 is not turned on and off in the steady running state of the vehicle where the control deviation ΔN i is small, and when the control deviation ΔN in is large as in the case of an acceleration/deceleration request operation. Since they are turned on and off only in transient states, the durability of the second solenoid valve 268 and the flow rate control valve 264 is significantly improved compared to the conventional case in which the second solenoid valve 268 is driven even when the vehicle is in a steady running state. There are advantages that can be enhanced.

Although one embodiment of the present invention has been described above based on the drawings,
The invention also applies in other aspects.

For example, in the embodiment described above, the -next hydraulic cylinder 54
and two types of first line hydraulic pressure Pf and second line hydraulic pressure P12 to act on the secondary side hydraulic cylinder 56.
was used, but the hydraulic pressure output from a single hydraulic source was constantly applied to the secondary hydraulic cylinder to control the tension of the transmission belt, while the hydraulic fluid from that hydraulic source was applied to the primary hydraulic cylinder. The hydraulic control device may be of a type in which the speed ratio is changed by a speed change control valve device that causes hydraulic oil in the primary hydraulic cylinder to flow into the cylinder or flow out of the primary hydraulic cylinder.

Further, in the above-mentioned embodiments, a belt-type CVTI 4 has been described, but the 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 amount of accelerator pedal operation 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.

Furthermore, in the speed change control of the CVT 14 in the above-described embodiment, control was performed so that the actual input shaft rotational speed N i n matched the target rotational speed N i n , but the speed ratio e
=Nout/Nt. Therefore, even if the speed ratio e is controlled so that the actual speed ratio e matches the target speed ratio el, it is substantially the same.

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. Further, the forward/reverse switching device 16 may have two or more forward gears.

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

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 first pressure regulating 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. FIG. 7 is a diagram showing the output characteristics of the second pressure regulating valve shown in FIG. 3. 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. FIG. 10 is a diagram illustrating the relationship between the operating states of the first solenoid valve and the second solenoid valve in the speed change control valve device of FIG. 9 and the shift state of the CVT shown in FIG. 2. 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.
FIG. 2 shows an engine brake running state, and FIG. 13 shows an unloaded running state. FIG. 14 is a diagram showing the output characteristics of the 111th pressure valve in FIG. 4 with respect to the primary side 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. Figure 16 shows the drive duty ratio I)ss of the 5th magnetic valve in Figure 1.
FIG. 3 is a diagram showing the relationship between the signal pressure P3° and the resulting signal pressure P3°. FIG. 17 is a diagram showing the change characteristics of the duty ratio I)ss of the fifth solenoid valve and the fourth line oil pressure P14 that is continuously changed in relation to it in the hydraulic circuit of 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. FIG. 20 is a flowchart illustrating the operation of the control device of FIG. 2. 14: CVT (continuously variable transmission) 262: Speed change direction switching valve 264: Flow rate control valve (speed change speed control valve) 266: First solenoid valve 268: Second solenoid valve 280 Nispool valve element (first valve element) 288 Varnish spool Benko (second Benko)

Claims (1)

[Scope of Claims] A hydraulic control device for a continuously variable transmission for a vehicle in which a speed ratio is changed steplessly, comprising: a hydraulic pressure generating device for driving a valve that generates hydraulic pressure for driving a valve; a first valve element movable between a speed reduction side position for changing the speed ratio in a speed reduction direction and a speed increase side position for changing the speed ratio in a speed increase direction; a speed change direction switching valve in which the first valve element is positioned at a speed increasing side position when the first valve element is not actuated; a first solenoid valve that switches the first valve to the deceleration side position, a flow rate suppression side position for suppressing the rate of change in the speed ratio, and a flow rate non-suppression side position for not suppressing the rate of change; a second valve element that can be used, and the hydraulic pressure for driving the valve is
a variable speed control valve in which the second valve is positioned at a flow rate suppression side position when the valve is not actuated; A hydraulic control device for a continuously variable transmission for a vehicle, comprising a second electromagnetic valve that switches a valve to the flow rate non-suppression side.