JPH02212657A - Hydraulic control device for belt type continuously variable speed change gear for vehicle - Google Patents

Abstract

PURPOSE:To prevent the generation of surplus tension of a transmission belt because of a centrifugal oil pressure in a hydraulic actuator on the driven side by a method wherein when a car speed exceeds a given range, an oil pressure for reducing a pressure is fed from an oil pressure signal generating means to a pressure regulating valve and when below, an oil pressure for boosting is fed. CONSTITUTION:When a car speed detected by a car speed sensor 462 exceeds a car speed set to an ROM, an electronic control device 460 controls ON and OFF of third and fourth solenoid valves 330 and 346 being an oil pressure signal generating means, feeds an oil pressure signal for reducing a pressure to the pressure regulating valve of a hydraulic control circuit, and reduces a second line oil pressure to a hydraulic cylinder 56 on the secondary side. Meanwhile, when a vehicle is brought into a low car speed and a car speed is reduced to a value lower than a value in a preset given range, an oil pressure signal for boosting is generated to increase an oil pressure in the cylinder 56 on the secondary side. This constitution improves durability by preventing the generation of surplus tension of a transmission belt, and besides enables a speed ratio to be rapidly changed to the highmost speed side during the rapid stop of a vehicle.

Description

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

2. Description of the Related Art A pair of variable pulleys are provided on the primary rotation shaft and the secondary rotation shaft, a transmission belt is wound around the pair of variable pulleys to transmit power, and the effectiveness of the pair of variable pulleys is 2. Description of the Related Art A belt-type continuously variable transmission for a vehicle is known that includes a pair of hydraulic actuators that each change a diameter. For example, the belt-type continuously variable transmission described in Japanese Patent Application Laid-Open No. 5198861 is one such example. In the hydraulic control device provided in such a belt-type continuously variable transmission, the tension of the transmission belt is adjusted by adjusting the hydraulic pressure in the driven side hydraulic actuator of the pair of hydraulic actuators according to the transmission I/Lux and speed ratio. A hydraulic control circuit is provided with a pressure regulating valve that provides the necessary and sufficient control of the pressure. In this type of hydraulic control circuit, it is inevitable that centrifugal hydraulic pressure will be generated in the driven hydraulic actuator as the driven hydraulic actuator rotates, especially when the vehicle is running at high speed. There was a risk that the tension in the power transmission belt would be excessive and its durability would be impaired.

On the other hand, as described in Japanese Patent Application Laid-Open No. 60-53258, while the rotational speed of the driven side rotating shaft of a belt type continuously variable transmission is detected, the centrifugal hydraulic pressure generated based on this rotational speed is At the same time, the centrifugal oil pressure should be subtracted from the pressure regulation target value, and the pressure saw III control servo valve equipped with a linear solenoid should be driven to obtain the corrected pressure regulation target value and supplied to the driven side hydraulic actuator. A hydraulic control device that continuously adjusts line hydraulic pressure is provided.

Problems to be Solved by the Invention However, the above-mentioned hydraulic control circuit has the disadvantage that the device is expensive because it is necessary to use a pressure control servo valve equipped with a linear solenoid.

The present invention has been made against the background of the above circumstances,
The purpose is to prevent the tension of the transmission belt from becoming excessive based on the centrifugal hydraulic pressure generated in the driven side hydraulic actuator, and to provide an inexpensive hydraulic control device.

Means for Solving the Problems The gist of the present invention for achieving the above object is to provide a pair of variable pulleys provided respectively on the downstream rotation shaft and the secondary rotation shaft, and In a belt-type continuously variable transmission for a vehicle, comprising a power transmission belt wound between the boosters and a pair of hydraulic actuators that respectively change the effective diameters of the pair of variable pulleys, one of the pair of hydraulic actuators A hydraulic control device of a type that controls the tension of the transmission belt by directly or indirectly regulating the hydraulic pressure in the driven-side hydraulic actuator, the device comprising: (a) a spool valve for regulating the hydraulic pressure in the driven-side hydraulic actuator; a pressure reducing oil pressure signal receiving chamber for receiving a pressure reducing oil pressure signal for applying a biasing force to the spool valve in the direction of decreasing the pressure regulating value; (b) a pressure regulating valve comprising a pressure increasing hydraulic pressure signal receiving chamber that receives a pressure increasing hydraulic pressure signal for applying a biasing force toward the vehicle; and (b) generating the pressure reducing hydraulic pressure when the vehicle speed exceeds a predetermined range. a hydraulic pressure signal generating means for supplying the pressure reducing hydraulic signal to the pressure receiving chamber, and when the vehicle speed falls below the predetermined range, generating the pressure increasing hydraulic signal and supplying the pressure increasing hydraulic signal to the pressure receiving chamber. There is a particular thing.

With this structure, when the vehicle speed exceeds a predetermined range, the pressure reducing oil pressure signal is generated by the oil pressure signal generating means and is supplied to the pressure reducing oil pressure signal receiving chamber of the pressure regulating valve. Therefore, the pressure regulating valve lowers the hydraulic pressure in the driven side hydraulic actuator.

This prevents the tension in the transmission belt from becoming excessive due to the centrifugal hydraulic pressure generated in the driven-side hydraulic actuator at high vehicle speeds. On the other hand, when the vehicle speed falls below a predetermined range, the pressure-increasing hydraulic pressure signal is generated by the hydraulic signal generating means and supplied to the pressure-increasing hydraulic signal receiving chamber of the pressure regulating valve. The hydraulic pressure in the driven hydraulic actuator is increased. This results in
When the vehicle speed becomes low enough to release the lock-up clutch, the hydraulic pressure in the driven side hydraulic actuator increases, and when the vehicle suddenly stops, the speed ratio of the belt-type continuously variable transmission quickly changes to the maximum deceleration side. It will be done. Further, since a pressure control servo valve equipped with a linear solenoid is not used as a pressure regulating valve that reduces the pressure in the driven side hydraulic actuator, the hydraulic control device becomes inexpensive. Note that the driven-side hydraulic actuator refers to a hydraulic actuator located on the driven side in the torque transmission direction, and when the vehicle is running with normal drive, the secondary hydraulic actuator is the secondary hydraulic actuator, and when the vehicle is running with engine braking, the secondary hydraulic actuator is the primary hydraulic actuator. The side hydraulic actuators shall be shown respectively.

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

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

The fluid coupling 12 connects a pump impeller 28 connected to the crankshaft 26 of the engine 10 and an input shaft 3 of the CVT 14.
a turbine impeller 32 fixed at zero and rotated by oil from the pump impeller 28; a lock-up clutch 36 fixed to the input shaft 30 via a damper 34;
An engagement side oil chamber 33 connected to an engagement side oil passage 322 described below and a release side oil chamber 3 connected to a release side oil passage 324 described below.
5. The inside of the fluid coupling 12 is always filled with hydraulic oil. For example, when the vehicle speed, the engine rotation speed, or the rotation speed of the turbine 28 exceeds a predetermined value, the hydraulic oil is supplied to the holding side oil chamber 33 and the releasing side oil is supplied. As the hydraulic oil flows out from the chamber 35, the lock-up clutch 36 is engaged, and the crankshaft 26 and the input shaft 30 are directly connected. On the other hand, when the vehicle speed, etc. falls below a predetermined value, hydraulic oil is supplied to the release side oil chamber 35 and hydraulic oil flows out from the retention side oil chamber 33, thereby releasing the lock-up clutch 36. .

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

The variable pulleys 40 and 42 are fixed rotating bodies 46 and 48 fixed to the input shaft 30 and the output shaft 38, respectively, and are provided on the input shaft 30 and the output shaft 38 so as to be movable in the axial direction but not relatively rotatable around the axes. The movable rotating bodies 50 and 52 are
is moved by the primary 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 of the CVT 14 is changed. (−
Rotational speed N of the output shaft 38. ut/rotational speed N8,) of the input shaft 30 is changed. Since the variable pulleys 40 and 42 have the same diameter, the hydraulic cylinder 5
4 and 56 have similar pressure receiving areas. Normally, the pressure of the hydraulic cylinders 54 and 56 located on the driven side is related to the tension of the transmission belt 44, and the second line oil pressure Pβ2 regulated by the second pressure regulating valve 102, which will be described later, is on the driven side. By being supplied to the hydraulic cylinder, the transmission belt 44 is maintained at an optimum belt tension within a range that does not cause slippage.

The forward/reverse switching device f16 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 its output shaft 58 and mesh with each other. A sun gear 66 that is fixed to the input shaft (output shaft of the CVT 14) of the forward/reverse switching device 16 and meshes with the planetary gear 62 on the inner circumferential side;
A ring gear 68 that meshes with the planetary gear 64 on the outer circumferential side, and a reverse brake 7 for stopping the rotation of the ring gear 68.
0, and a forward clutch 72 that connects the carrier 60 and the input shaft 38 of the forward/reverse switching device 16.

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 3 of the CVT 14
8 and the output shaft 58 of the forward/reverse switching device 16 are directly connected to transmit power in the forward direction of the vehicle. Further, when the reverse brake 70 is 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 a hydraulic control circuit for controlling the vehicle power transmission device shown in FIG. The 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. There is. 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 suction 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 suction 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 suction oil passage 78 and the lockup clutch pressure oil passage 92. 1st line oil pressure PI in oil passage 80! , , are pressure regulated. In addition, the first line oil pressure PI is controlled by a second pressure regulating valve 102 of a pressure reducing valve type.

By reducing the pressure, the second line oil pressure Pβ2 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 Sea I・112, Return Spring]
14 and a plunger 116. Further, a first land 118, a second land 120, and a third land 122 are formed in order at the shaft end of the spool valve element 110, the diameters of which increase in this order. A chamber 126 is provided between the second land 120 and the third land 122, into which the second line hydraulic pressure Pffi2 is introduced as feedback pressure through the throttle 124, and the spool valve 1.1.0 is connected to the second line hydraulic pressure Pffi2. P
It is biased in the valve closing direction by J22.

Further, a chamber 130 is provided at the end of the first land 118 of the spool valve element 110, through which a speed specific pressure Pe is introduced via a second line oil pressure increase control valve 391, which will be described later, via a throttle 128. The valve element 110 is biased in the valve closing direction by the speed specific pressure Pe. Inside the second pressure regulating valve 102, a biasing force in the valve opening direction of the return spring 11i is applied to the spool valve element 110 via a spring seat 112.

Further, a chamber 132 for applying a throttle pressure Pth (described later) is provided on the end face side of the plunger 116, and the spool valve element 110 is urged in the valve opening direction by this throttle pressure Pth. There is. Therefore, the pressure receiving area of the first land 118 is AI, the area of the cross section of the second land 120 is A2, and the area of the cross section of the third land 122 is A.
3. If the pressure receiving area of the plunger 116 is A4 and the urging force of the return spring 114 is W, then the spool valve 11
Equilibrium is achieved at a position where the zero-order equation (1) holds true. That is, by moving the spool valve element 110 according to equation (1), the hydraulic oil in the first line oil passage 8o guided to the boat 134a flows into the boat], 34
The state in which the hydraulic oil in the second line oil passage 82 guided to the boat 134b is caused to flow into the second line oil passage 82 through the drain boat 134b is repeated. 2nd line hydraulic PI! ,2
is generated. Since the second line oil passage 82 is a relatively closed system, the second iJil pressure valve 10
2 is the first line oil pressure Pj2.2, which is a relatively high oil pressure as described above. By reducing the pressure of the second line oil pressure Pρ2
is generated as shown in FIG.

I! 22=(A4 ・Pth+W-8+ ・Pe)/
(A3-A2)・・・・・(1) Note that the speed supplied to the chamber 130 through the second line oil pressure increase control valve 391, which will be described later, in connection with the vehicle speed falling below a predetermined range. By shutting off the specific pressure PG and making the inside of the chamber 130 atmospheric pressure, the biasing force of the spool valve 110 in the valve opening direction increases relatively, and the second line oil pressure P12 increases by a predetermined amount. It is now possible to do so. Furthermore, a speed specific pressure P,
is introduced into the chamber 136, and when the vehicle speed exceeds the predetermined range mentioned above, the speed specific pressure P8 is supplied to the chamber 136. , the biasing force of the spool valve element 110 in the valve closing direction is relatively increased, and the second line oil pressure PQ□ is reduced by a predetermined amount. The second line hydraulic characteristics in this 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. A plunger 148 is provided.

The spool valve 140 communicates with the first line oil passage 80 and is connected to the bow) L50a and the trenpo 1-150b or 150.
c, and its first land 152
1st line oil pressure PA as feedback pressure on the end face of
A reservoir chamber 153 is provided in which the pressure is applied via a throttle 151, and the spool valve element 140 is biased in the valve opening direction by this first line oil pressure PL.

A chamber 156 for introducing the throttle pressure P 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 second plunger 148
There are hydraulic pressures p, t, in the primary side hydraulic synonda 54 between
A chamber 157 is provided for guiding the oil through the branch oil passage 305, and a second chamber 157 is provided on the end face of the second plunger 148.
Line hydraulic pressure P! A chamber 158 is provided for guiding 2.

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 to A1, and the pressure receiving area of the first land 152 of the first plunger 146 is 1st
If the cross-sectional area of the 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, then the spool valve 140
is balanced at a position where the following equation (2) holds true, and the first line oil pressure Pffi is regulated.

Pffi+= [(PH, l or Pj22) ・ At+Pt
h(8.-8t)+hl/8.

・ ・(2) In the first pressure regulating valve 100, the hydraulic pressure inside the negative side hydraulic cylinder 54 is P8. , is the second line oil pressure Pf2z (in the steady state, Pj22 - the secondary side hydraulic cylinder 56 internal oil pressure P, ,
.
0 in the valve closing direction, but - the hydraulic pressure P in the next side hydraulic cylinder 54. is lower than the second line oil pressure Plz, the first plunger 146 and the second plunger 148 are in contact with each other, so that the second line oil pressure PI! acting on the end face of the second plunger 148 is lower than the second line oil pressure Plz. , z acts on the spool valve element 140 in the valve closing direction. In other words, the - next side hydraulic cylinder 54 internal hydraulic pressure P,... and the second line hydraulic pressure P
The second plunger 148, which receives the hydraulic pressures IV and 2, applies an acting force based on the higher of these hydraulic pressures in the direction of closing the spool valve element 140. In addition, in this embodiment, the first land 152 and the second land of the spool valve 140
The chamber 160 provided between the land 159 and the land 159 is drained, and in this embodiment, the first line oil pressure Pj2. The second line oil pressure PI! is sent to the chamber 160 for the purpose of lowering the oil pressure PI! A first line oil pressure reduction control valve for supplying z is not provided.

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 ratio pressure Pe represents the actual speed ratio of the CVT 16 and is generated by the speed ratio detection valve 182. That is, the throttle valve opening detection valve 180 and the cam 18 rotated together with the throttle valve (not shown)
4 and the cam surface of this cam 184, and this cam 18
The plunger 186, which is driven in the axial direction in relation to the rotation angle of 4, is positioned at a position where the thrust from the plunger 186 applied via the spring 188 and the thrust due to the first line oil pressure Pp are balanced. The first
The line oil pressure PffI is reduced, and the actual throttle valve opening θ1. and a spool valve element 190 that generates a throttle pressure Pth corresponding to the throttle pressure Pth. FIG. 5 shows the relationship between the throttle pressure Pth and the throttle valve opening θth, which are supplied to the first pressure regulating valve 100, the second pressure regulating valve 102, and the third pressure regulating valve 220 through the oil passage 84, 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 CVTl4 and is moved in the axial direction by an amount of displacement equal to the amount of displacement in the axial direction. A spring 194 correspondingly transmits a biasing force, and while receiving the biasing force from this spring 194, receiving the second line oil pressure Pρ2 and being positioned at a position where the thrusts of both are balanced, the discharge flow rate to the drain is reduced. The spool valve 198 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 VTl, 4 (■ 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 19
8 reduces the flow rate of the hydraulic oil discharged to the drain, thereby increasing the hydraulic pressure downstream of the orifice 196. This working oil pressure is the speed specific pressure Pe, and the sixth
As shown in the figure, it increases as the speed ratio e increases. Then, the velocity specific pressure P generated in this way
e is supplied to the third pressure regulating valve 220 and the second line oil pressure increase control valve 391 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 oil pressure Pff2 supplied from the second line oil path 86 through the second line oil passage 86, the speed specific pressure Pe is equal to the second line oil pressure P! While the value is limited to 2 or more, the second pressure regulating valve 102 that operates according to equation (1) reduces the second line oil pressure Pr2 as the speed specific pressure Pe increases. Therefore, when the speed specific pressure Pe increases to a predetermined value and becomes equal to the second line oil pressure [122], both of them are saturated and become constant thereafter.

FIG. 7 shows the output characteristics of the second line oil pressure Pt2 that is regulated in the second pressure regulating valve 102 in relation to the speed specific pressure Pe described in "2". That is, the transmission belt 4 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 of No. 4 to the optimum value can be obtained only by the hydraulic circuit, and the second line hydraulic pressure PI! , 2 has the advantage that the hydraulic circuit is significantly cheaper than the case where the hydraulic circuit is generated.

The third pressure regulating valve 220 has an optimum third line oil pressure Pffi for operating the reverse brake 70 and the forward clutch 72 of the forward/reverse switching device 16.

It is something that generates. That is, the third pressure regulating valve 220
A spool valve 222 that opens and closes between the first line oil passage 80 and the third line oil passage 88, and a spring sear 1-22.
4, a return spring 226 and a plunger 228. A chamber 236 is provided between the first land 230 and the second land 232 of the spool valve 222, into which the third line oil pressure Pf is introduced as feed pressure through the throttle 234. Third
It is biased in the valve closing direction by line oil pressure Pff3. In addition, the first land 2 of the spool valve 222
30 side is provided with a chamber 240 into which the speed specific pressure Pe is guided through the throttle 238, and the spool valve element 222 is biased in the valve closing direction by the speed specific pressure Pe. Inside the third pressure regulating valve 220, a biasing force in the valve opening direction of a return spring 226 is applied to the spool valve element 222 via a spring seat 224. Further, a chamber 242 for applying throttle pressure P, . . . is provided on the end face of the plunger 228.
2 is this throttle pressure P71. The valve is biased in the direction of opening the valve. In addition, the first part of the plunger 228
A chamber 248 is provided between the land 244 and a second land 246 having a smaller diameter than the land 244 for guiding a third inner hydraulic pressure Pp,3 only when the vehicle is moving backward. Therefore, the third line oil pressure P23 is calculated from the same formula (1) as the speed specific pressure Pe and the throttle pressure PL.
The pressure is regulated to an optimal value based on l. This optimal value is a value necessary and sufficient to ensure torque can be transmitted without slipping in the forward clutch 52 or the reverse brake 50. Furthermore, when traveling in reverse, the third line oil pressure Pρ3 is guided into the chamber 248, so the force urging the spool valve element 222 in the valve opening direction is increased and the third line oil pressure Pp3 is guided into the chamber 248.
is enhanced. As a result, the forward clutch 72 and the reverse brake 70 can provide torque capacities suitable for forward movement and reverse movement, respectively.

The third line oil pressure Pj2° regulated as described above is supplied to the forward clutch 72 or the reverse brake 70 by the manual valve 250.

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 when the shift lever 252 is operated in the N (neutral) range, the third line oil pressure is Does not output Pn, but L (low), S (second)
, when the D (drive) range is being operated, the third
The line oil pressure Pffi, l is exclusively output from the coupler 1-258 to the forward clutch 72 and the reverse inhibit valve 4.
20 to the chamber 432 and at the same time the reverse brake 70
When the R (reverse) range is operated, the third line oil pressure PIV, 3 is supplied from the output boat 256 to the boat 422a of the third pressure regulating valve 220, lock-up control valve 320, and reverse inhibit valve 420, respectively. At the same time, the reverse inhibit valve 420
The oil is supplied to the reverse brake 70 through the engine, and at the same time, the oil is drained from the forward clutch 72. When the P (parking) range is operated, oil is drained from both the forward clutch 72 and the reverse brake 70.

Incidentally, the accumulators 342 and 340 are for gradually increasing the hydraulic pressure to smoothly advance frictional engagement, and are connected to the forward clutch 72 and the reverse brake 70, respectively. Furthermore, 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 PI regulated by the first pressure regulating valve 100! , , and the second line oil pressure P regulated by the second pressure regulating valve 102. In order to adjust the speed ratio e of the CVT 14, the primary side hydraulic cylinder 54 and the secondary side hydraulic cylinder 2 are controlled by the speed change control valve device 260. 56 and the other. The speed change control valve system W 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 Pj2 is used to drive 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 Pβ1, and is guided through the fourth line oil passage 370.

As shown in detail in FIG. 9, the speed change direction switching valve 262 is
A spool valve controlled by the first electromagnetic valve 266, which connects with the flow rate control valve 264, four first connection paths 270, a second connection path 272 having a first throttle 271,
Boats 278a, 278c, 278e, and 278g that communicate with the third connection path 274 and the fourth connection path 276, respectively,
A drain boat 278b communicating with the drain, and a first line hydraulic pressure Pj2. Boat 278d is supplied with the second line hydraulic pressure PI! . Spool valve 280 arranged so that it can
and a spring 282 that urges the spool valve element 280 toward the second position. The spool valve 280 is provided with four lands 279a, 279b, 279c, and 279d for opening and closing between the boats. Since the end face of the spool valve element 280 on the spring 282 side is open to the atmosphere, no hydraulic pressure is applied thereto. However, when the first electromagnetic valve 266 is in the OFF state, that is, in the closed state, a fourth line hydraulic pressure P regulated by the fourth pressure regulating valve 170 is provided on the end surface of the lower end side of the spool valve element 280.
ffi is applied, but in the on state, that is, in the open state, the downstream side of the throttle 284 is exhausted and the fourth line oil pressure Pl is not applied. Therefore, during the period when the first solenoid valve 266 is in the on state, the spool valve 28
0 is positioned in the second position and the boat 278a and the boat)
278b, and between the boats 278d and 278e, respectively.
80 and the boats 278f and 278g are closed, but during the period when the first solenoid valve 266 is in the OFF state, the spool valve element 280 is positioned in the first position, resulting in a switching state opposite to the above. .

The flow rate control valve 264 is a spool valve controlled by a second electromagnetic valve 268, and is a spool valve that connects the four-tree first connection path 2.
70, boats 286a and 286c that communicate with the second connection path 272, the third connection path 274, and the fourth connection path 276, respectively.
, 286d, 286f, a boat 286b communicating with the downstream hydraulic cylinder 54, a boat 286e communicating with the secondary hydraulic cylinder 56, and one end of the movement stroke (the ninth
A spool valve 288 is slidably disposed between a first position (upper end in the figure) and a second position (lower end in Figure 9) of the other end of the movement stroke;
Spring 290 biasing 88 toward the second position
It is equipped with The spool valve 28B has four lands 287a 28 for opening and closing between each boat.
7b, 287c and 287d are provided. Similar to the speed change direction switching valve 262, no hydraulic pressure is applied to the end surface of the spool valve element 288 on the spring 290 side because it is open to the atmosphere. However, when the second solenoid valve 268 is in the OFF state, that is, in the closed state, the fourth line hydraulic pressure PN regulated by the fourth pressure regulating valve 170 is applied to the lower end surface of the spool valve element 288; state, that is, the open state, the pressure downstream of the throttle 292 is exhausted and the fourth
The line oil pressure Pf4 becomes inactive. For this reason,
The second solenoid valve 268 is in the on state (duty ratio is 00%)
), the spool valve 288 is placed in the second position, opening the spaces between the boats 286c and 286b and the boats 286f and 286e, and opening the spaces between the boats 286a and 286b and the boats 286a and 286b. 2
Although the space between 86d and 286e is closed, the second solenoid valve 2
68 is in the off state (duty ratio is 0%), the spool valve 288 is positioned at the first position and is in the switching state opposite to the above. Note that during the period when the second electromagnetic valve 268 is in the OFF state, the boats 286c and 286b are slightly communicated through the throttle 294. The secondary hydraulic cylinder 56 is connected to the second line oil passage 82 via a throttle 296 and a check valve 298 that are parallel to each other. The throttle 296 and the check valve 298, which are parallel to each other, connect the first line to the secondary hydraulic cylinder 56 during a deceleration shift in which the pressure inside the secondary hydraulic cylinder 56 is set to a relatively high pressure side or when running under engine braking. When the hydraulic pressure PA is supplied, the hydraulic pressure P in the secondary hydraulic cylinder 56. This is to prevent a large amount of ut (-pp, ) from flowing out into the second line oil passage 82 and decreasing.

Therefore, when the first solenoid valve 266 is on,
As shown by the solid line in FIG. 9, the hydraulic oil in the first line oil passage 80 is connected to the boat 1-278d, the boat 278e, the third connection passage 274, the boat 286d, the ball I-286e, and the secondary oil passage. 302 into the secondary hydraulic cylinder 56, while the hydraulic oil in the secondary hydraulic cylinder 54 is
-Next oilway 300, boat 1-286 b, boat 286
a, first connection path 270, boat 278a, boat 278
It is discharged to the drain through b. From this, CVT
], the speed ratio e of 4 is changed in the deceleration direction.

Conversely, when the first solenoid valve 266 is off, the ninth
As shown by the broken line in the figure, the hydraulic oil in the first line oil path 80 is connected to the boat 278d, the boat 278c, and the second connection path 27.
2. Boat 286c, Boat 1-286b, - While the hydraulic oil in the secondary hydraulic cylinder 56 flows into the primary hydraulic cylinder 54 through the downstream oil passage 300, the hydraulic oil in the secondary hydraulic cylinder 56 flows through the secondary oil passage 302, It is discharged to the second line oil path 82 through the boat 286f, the fourth connection path 276, the boat 1-278g, and the boat 278f. From this, C
If the speed ratio e of VTl,4 is changed in the speed increasing direction. Note that a second throttle 273 is provided between the branch point of the downstream side oil passage 300 to the first pressure regulating valve 100 and the bow 286b of the flow rate control valve 264.

FIG. 10 shows the first solenoid valve 266 and the second solenoid valve 2.
Driving state of 68, shifting direction and speed ratio of CVTl4
shows the relationship between the rate of change of

Note that in the case of the shift mode (d) in which both the first solenoid valve 266 and the second solenoid valve 268 are in the OFF state, the hydraulic oil in the first line oil passage 80 flows through the throttle hole 2 of the spool valve 288.
94 to the primary hydraulic cylinder 54, and the hydraulic oil in the secondary hydraulic cylinder 56 is supplied to the primary hydraulic cylinder 54 through the throttle 296.
It is gradually discharged to the second line oil passage 82 through the passage. In addition, in the case of the shift mode (c) in which both the first solenoid valve 266 and the second solenoid valve 268 are in the ON state, the hydraulic oil in the second line oil passage 82 is provided in parallel in the bypass oil passage 295. The hydraulic fluid in the downstream hydraulic cylinder 54 is supplied through the throttle 296 and the check valve 298 into the secondary hydraulic cylinder 56, and the hydraulic fluid in the downstream hydraulic cylinder 54 is also supplied to the secondary hydraulic cylinder 54 through a small amount of water that is actively or inevitably formed on the sliding portion of the piston. It is gradually discharged from the gap.

As described above, since the bypass oil passage 295 is provided between the secondary hydraulic cylinder 56 and the second line oil passage 82, the flow rate control valve 264 is synchronized with the duty drive of the flow control valve 264, Hydraulic P. The pulsation occurring in the ut is suitably suppressed. Hydraulic pressure P in the secondary hydraulic cylinder. The spike-shaped upper peaks of I and L are released by the aperture 296, and P o
This is because the peak below utO is compensated for through the check valve 298.

The check valve 298 includes a valve seat 299 with a flat seating surface, a valve element 301 with a flat contact surface that contacts the seating surface, and a valve element 301 that faces the valve seat 299. Equipped with a biasing spring 303, 0.2 kg/c
It is designed to open with a pressure difference of about m2.

Here, the first line oil pressure Pi in CVT14 is as shown in FIG. 11 during positive drive driving (when the driving torque T is positive), and as shown in FIG. 12), a hydraulic pressure value as shown in FIG. 12 is desired. 11 and 12 both show the input shaft 3.
0 indicates the oil pressure value required when the speed ratio is changed within the entire range while being rotated with a constant shaft torque. In this embodiment, the negative side hydraulic cylinder 5
Since the pressure receiving area of 4 and the secondary hydraulic cylinder 56 are equal,
During forward driving in FIG. 11, the oil pressure P in the primary hydraulic cylinder 54 is greater than the oil pressure P in the secondary hydraulic cylinder 56.

ut % P when running under engine brake as shown in Figure 12. u
t>P i, , and in both cases, the hydraulic pressure in the driving side hydraulic cylinder>the hydraulic pressure in the driven side hydraulic cylinder. The above pin in during normal drive running is what generates the thrust of the hydraulic cylinder on the drive side, so it is necessary to make sure that the hydraulic cylinder can generate the compressive force to obtain the target speed ratio, and to reduce the power loss. In order to reduce the first line oil pressure P
ffi.

is the above P1. ．． It is desirable to adjust the pressure to a value that is the sum of a necessary and sufficient margin oil pressure α. However, the first line oil pressure PIV shown in FIGS. 11 and 12 above.

It is impossible to adjust the pressure based on the hydraulic pressure in one of the hydraulic cylinders. Therefore, in this embodiment, the first pressure regulating valve 100 is provided with a second plunger 148, and the pi
The biasing force based on the higher oil pressure of n and second line oil pressure Pβ2 is the spool valve element 14 of the first pressure regulating valve 100.
0. As a result, as shown in FIG. 13, for example, the curve without P and P o
During no-load running when the curve does not indicate ut and intersects with the curve, the first line oil pressure PI! , l is P8. , and the second line oil pressure P12, whichever is higher, plus the margin value α. Thereby, the first line oil pressure P21 is controlled to a necessary and sufficient value, and power loss is minimized. Incidentally, the first line oil pressure P shown by the broken line in FIG.
2. This is 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 is clear from equation (2). So, the first in relation to the throttle pressure P th
Line oil pressure PN is increased. Said first pressure valve 1
The pressure receiving area of each part of 00 and the biasing force of spring 144 are set in this manner. At this time, the first
As shown in FIG. 14, the first line oil pressure Pρ, which is regulated by the 1itP1 pressure valve 100, is P8. , or P
. It increases according to ut and throttle pressure Pth, but is saturated at a maximum value corresponding to throttle pressure Pth. As a result, while the speed ratio e reaches the maximum value and the decrease in the groove width of the primary variable pulley 40 is mechanically prevented, the hydraulic pressure P8 in the downstream hydraulic cylinder 54. ．． Even if Pf increases, the first line oil pressure Pf, which is always controlled to be higher than it by an allowance value α, is prevented from increasing excessively.

In the first pressure regulating valve 100, the hydraulic oil flowing out from the bow 1-150b is guided to the lock-up clutch pressure oil passage 92, and the hydraulic oil flows out from the bow 1-150b 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 ct. 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;
It is equipped with a chamber 316 to which clutch hydraulic pressure Pct is supplied through a lock-up quick release valve 400 (described later) at the time of sudden release, and a plunger 317 that receives the hydraulic pressure in the chamber 316 and urges the spool valve element 312 in the valve closing direction. , the spool valve 312 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 maintaining a constant lock-up clutch oil pressure. PCI is generated. Also, during sudden release, the clutch oil pressure P c
When t is supplied to the chamber 316, the lock-up clutch 3
Clutch oil pressure PcL to release 6 more quickly
is enhanced. The hydraulic oil flowing out from the lock-up clutch pressure regulating valve 310 is sent through the throttle 318 and the lubricating oil passage 94 to lubricate each part of the transmission, and is also sent to the suction oil passage 78 of the oil pump 74.
It is refluxed to

The lock-up clutch oil pressure P e+ regulated as described above is selectively supplied to the engagement-side oil passage 322 and the release-side oil passage 324 of the fluid coupling 12 by the lock-up control valve 320, and is supplied to the lock-up clutch 36. is now in a bound or released state. That is, the lock-up control valve 320 connects the lock-up clutch pressure oil passage 92 to the engagement side oil passage 322 and the release side oil passage 324.
A spool valve element 326 is selectively connected to the spool valve element 326, and a spring 328 biases the spool valve element 326 toward the release side. Upper end of spool valve 326 (spring 3
28 side) is connected to the third line hydraulic pressure P! from the output boat 256 of the manual valve 250 via the oil passage 257 only when the R range is selected. 3 is introduced, but other ovens are provided with a drain chamber 334, while a normal oven type third solenoid valve 330 is in the on state on the lower end side (non-spring 328 side) of the spool valve 326. A chamber 332 is provided into which a signal pressure P5OL3 is introduced when . The third solenoid valve 330 is in the on state (closed state)
When , the signal pressure P on the downstream side of the throttle 331 is equal to the clutch oil pressure PCI. L3 is generated, but when the third solenoid valve 330 is in the off state (open state), the downstream side of the throttle 331 is drained and the signal pressure P
5oL3 is now resolved. That aperture 3
31 and the solenoid valve 330 constitute means for generating a signal pressure P5oL3, and the signal pressure PgoL3 is generated not only from the lockup control valve 320 but also from the second line oil pressure increase control valve 391, the lockup quick release valve 400, and the reverse lockup control valve 320. are supplied to inhibit valves 420, respectively.

Therefore, in a shift range other than the R range, when the third solenoid valve 330 is in the on state, the signal pressure P5oL3 is introduced into the chamber 332, but since the chamber 334 is at atmospheric pressure, the spool valve 326 is spring 328
Since the lock-up clutch 36 is positioned to the side, the hydraulic oil in the lock amplifier clutch pressure oil passage 92 is supplied to the engagement side oil passage 322, and the lock-up clutch 36 is brought into a stopped state. On the other hand, when the third solenoid valve 330 is in the OFF state, the chamber 332 is at atmospheric pressure, and the spool valve element 326 is positioned downward in FIG. 1 according to the biasing force of the spring 328. The hydraulic oil in the lock-up clutch pressure oil passage 92 is supplied to the release side oil passage 324, and the lock-up clutch 3
6 is considered to be in a released state.

Furthermore, when the shift position is changed to the R range, the third line oil pressure P13 is supplied to the chamber 334, so the third line oil pressure PI ! , 3 and the spring 328 become larger, and the third solenoid valve 33
Regardless of the open/closed state of 0, the spool valve 326 is preferentially positioned at the lower side in FIG. 1, and the lock-up clutch 36 is released.

In addition, the hydraulic oil that flows out from the throttle 336 when engaged, and the hydraulic oil that flows out from the lock-up control valve 320 by being returned from the lock-up clutch 36 via the engagement-side oil passage 322 when it is not engaged, After the pressure is regulated below a certain value by the Tara hydraulic control well 338, the oil is returned to an oil tank (not shown) via an oil cooler 339.

Back pressure control of the accumulators 342 and 340 provided in the forward clutch 72 and reverse brake 70, respectively, will be explained. Lock-up clutch pressure oil passage 92
The hydraulic oil flowing out through the throttle 344 is controlled by a normal oven type fourth solenoid valve 346, and the oil pressure is changed with respect to the duty ratio DS4, as shown in FIG. That is, the throttle 344 and the fourth solenoid valve 346 have a signal pressure P. It functions as a signal pressure generating means for generating L4. In this way, the signal pressure P5 is regulated by the %l duty ratio Ds4 of the fourth solenoid valve 346.
614 is connected to the solenoid pressure switching valve 35 via the oil passage 348.
It leads to 0. This solenoid pressure switching valve 350 has a first
As shown in detail in FIG. 6, a boat 352a communicates with the oil passage 354, a boat 352c communicates with the oil passage 348, and a boat 1-35 communicates with the oil passage 356.
2d, and the drain boat 352e, and a first position that is one end of the moving stroke (the upper end in FIG. 16) and a second position that is the other end of the moving stroke (the lower end in FIG. 16). It includes a disposed spool valve element 358 and a spring 360 that biases the spool valve element 358 toward the first position. The above spool valve 35
The third line oil pressure Pf is in the chamber 362 on one end (upper end) side of 8.
fi is constantly guided, while the hydraulic pressure in the forward clutch 72 is guided to a chamber 364 on the other end side (spring 360 side) of the spool valve element 358. Therefore, when the shift position is in the P, R, N range, the hydraulic cylinder of the forward clutch 72 is operated by the manual valve 25.
Since the water is drained by 0, the pressure inside the chamber 364 is also exhausted. For this reason, the spool valve 358 is connected to the chamber 36.
2, the boat 352c and the boat 352b are positioned in the second position according to the third line oil pressure P23 guided to the
Since communication is established between the boat 352d and the boat 352e, the signal pressure P,. , 4 is oil passage 35
4 to the chamber 177 of the fourth pressure regulating valve 170, and the hydraulic pressure in the oil passage 356 is drained. However, N
When shifting from the range to the S or L range, the hydraulic pressure in the hydraulic cylinder of the forward clutch 72 increases over time according to a predetermined function due to the relaxation action of the accumulator 342 at the initial stage. Increases to PE3. Therefore, before the forward clutch 72 is engaged (the inside of the chamber 364 is at the third line oil pressure Pj23).
), the signal pressure in the oil passage 348 is P5aL.
4 is the fourth pressure regulating valve 17 through the solenoid pressure switching valve 350.
0, but when the forward clutch 72 is engaged (the pressure inside the chamber 364 has increased to the third line oil pressure P42.), the spool valve element 358 is located at the first position,
The boats 352b and 352a communicate with each other, and the boat 352C and ports 1-352d communicate with each other, and the oil passage 354
As the inside is drained, the signal pressure P inside the oil passage 348
5oL4 is a solenoid pressure switching valve 350 and an oil passage 356
to the second line oil pressure drop control well 380 and lockup quick release valve 400.

Here, the back pressure control of the accumulators 340 and 342 is as follows:
This is done to reduce the shift shock (maintenance shock) during N→D shift and N-+R shift, and the shock is alleviated by suppressing the increase in the oil pressure in the hydraulic cylinder for a short period of time when the clutch is engaged.

Therefore, a fourth pressure regulating valve 17 is installed in 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.
The fourth line oil pressure Pf, which is controlled by 0, is changed and supplied through the fourth line oil passage 370, thereby controlling the oil pressure change mitigation effect by the accumulator 342.34O.

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 fourth line hydraulic pressure P! is applied between the first land 173 and the second land 174 of the spool valve 171 to act as a feedback pressure. A chamber 176 is provided in which the spool valve 17 is introduced through the throttle hole 175.
A signal pressure ps is applied to the end face of the spring 172 of No. 1 in the valve opening direction.

, 4 is provided, and a chamber 177 for introducing the spool valve 17 is provided.
The end face of the non-spring 172 example is open to the atmosphere. In the fourth pressure regulating valve 170 configured in this way, the spool valve element 171 is set to the fourth line hydraulic pressure PI! , the biasing force in the valve closing direction based on the feedback pressure corresponding to 4, the biasing force in the valve opening direction due to the spring 172, and the signal pressure P
As a result of being operated so that the biasing force in the valve opening direction based on 5O14 is balanced, the fourth line oil pressure PJ24 is regulated to a pressure corresponding to the signal pressure Pso,a. That is,
During the N-+D shift and the N→R shift, while the signal pressure P5o (4) is being supplied to the fourth pressure regulating valve 170 through the solenoid pressure switching valve 350, as shown in FIG. is controlled to a value corresponding to the duty ratio D□ of the fourth solenoid valve 346, so the fourth solenoid valve 346 adjusts the duty ratio so as to generate back pressure suitable for reducing shift shock (engagement shock). Furthermore, as the oil pressure in the forward clutch 72 rises to the third line oil pressure P2, the fourth pressure regulating valve 170
When the signal pressure P5o14 supplied to the chamber 177 is shut off by the solenoid pressure switching valve 350 and the inside of the chamber 177 is released to the atmosphere, the fourth line oil pressure Pf4 is changed to a comparison value corresponding to the biasing force of the spring 172 in the valve opening direction. A low 4kg/cm2
Controlled to a certain degree of pressure. The 4th line oil pressure PI is regulated to this constant pressure! , , are used exclusively as driving oil pressure for the speed change direction switching valve 262 and the flow rate control valve 264. Note that the accumulator 372 provided in the oil passage 354 generates a signal pressure p s related to the duty drive frequency of the fourth solenoid valve 346 .

, 4 to absorb the pulsation.

Returning to FIG. 1, the second line oil pressure reduction control well 380 is
This is provided to prevent overload from being applied to the transmission belt 44 due to the centrifugal hydraulic pressure in the secondary side hydraulic cylinder 56. Second line hydraulic pressure PE2 mainly supplied to the secondary side hydraulic cylinder 56 which is the driven side
decrease. In addition, the second line oil pressure increase control valve 391
is for increasing the second line oil pressure P12 when the vehicle speed falls below a predetermined speed so that the speed ratio of the CVT 14 can be quickly changed to the maximum deceleration side before a sudden stop of the vehicle. The second line oil pressure Pρ2 is increased in synchronization with the release of the clutch 36.

The second line oil pressure increase control valve 391 has a speed specific pressure P,
Boats 382a and 38 connected to oil passage 86 leading to
4. a, a boat 382b connected to the chamber 130 of the second pressure regulating valve 102, a boat 384b connected to the second line oil pressure increase control valve 391, a drain boat 1-382c and 384c, and a first boat at the upper end of the movement stroke. A spool valve element 386 is slidably disposed between this position and a second position, which is the lower end of the movement stroke, and a spring 3 urges the spool valve element 38G toward the second position.
88, and a chamber 390 for receiving a signal pressure P5ot3 applied to the lower end of the spool valve element 386. Therefore, when the signal pressure P5,3 is supplied to the chamber 390 and the spool valve element 386 is moved to the first position against the biasing force of the spring 388, the speed specific pressure P,... The second pressure regulating valve 10 through the boat 382b
2 chamber 130, and boat 382a and boat 3
82b to the boat 392a of the second line oil pressure reduction control valve 380, and the signal pressure P6°13 is supplied to the chamber 390, and the spool valve element 386 is connected to the spring 38.
When moved to the second position according to the urging force of 8,
The speed specific pressure P8 that has been supplied to the chamber 130 of the second pressure regulating valve 102 and the bow 392a of the second line oil pressure drop control well 380 is released to the atmosphere.

The second line oil pressure decrease control well 380 is connected to the boat 384b of the second line oil pressure increase control valve 391.
92a, a boat 392b connected to the chamber 136 of the second pressure regulating valve 102, and a drain port 392c, and the second
The chamber 136 of the pressure regulating valve 102 is connected to the second line oil pressure increase control valve 3.
A spool valve 393 that selectively switches between the boat 384b of 91 and the atmosphere, a spring 394 that biases the spool valve 393, and a signal pressure P5°14 that acts on one end surface of the spool valve 393. Room 39 for reception
When the signal pressure P5oLa is supplied to the chamber 395, the spool valve element 393 moves against the biasing force of the spring 394. When J+ is applied, the speed specific pressure PQ passing through the second line oil pressure increase control well 391 becomes Bo) 392b
is supplied from the chamber 136 of the second pressure regulating valve 102 to the chamber 395.
When the supply of signal pressure P5oL4 to B is canceled and the spool valve element 393 is moved according to the biasing force of the spring 394, the chamber 136 of the second pressure regulating valve 10'2 is moved to the drain boat 39.
It is designed to be released to the atmosphere from 2c.

Therefore, as shown in FIG. 18, the third solenoid valve 330
In the case of normal driving in which the lock-up clutch 36 is engaged and the fourth solenoid valve 346 is in the on state and the fourth solenoid valve 346 is in the off state, the chamber 136 of the second pressure regulating valve 102 is at atmospheric pressure and the chamber 130 is at atmospheric pressure. is the speed specific pressure P. is supplied, so the second
The line oil pressure Pβ2 is controlled according to (1) 2 and has normal characteristics as shown in FIG. However, the third solenoid valve 3
30 is in the off state and the lock-up clutch 36 is in the released state such that the fourth solenoid valve 346 is in the on or off state, the chamber 130 and the second pressure regulating valve 102 are in the released state, as shown in FIG. 136 are both at atmospheric pressure, so the second line oil pressure PI! , 2 are controlled according to the following equation (3), and as shown by the solid line in FIG. 19, they are increased from the normal value (broken line) and have flat characteristics. As a result, in a low vehicle speed state where the lock-up clutch 36 is released, the second line oil pressure Pρ2 is increased, especially on the side where the speed ratio is large, so that when the vehicle suddenly stops, the CVT
The speed ratio of 14 can be quickly returned to the lowest deceleration side.

When the third solenoid valve 330 is in the on state and the fourth solenoid valve 346 is in the on state, the speed specific pressure P is applied to the chambers 130 and 136 of the second pressure regulating valve 102 as shown in FIG. are also supplied, so the second line oil pressure P12
By controlling according to the following equation (4), as shown by the solid line in FIG. 20, it is lowered than the normal value shown by the broken line. This eliminates excessive tension in the transmission belt 44 due to centrifugal hydraulic pressure generated in the secondary hydraulic cylinder 56 during high-speed running, improving the durability of the transmission belt 44 and reducing power loss.

Furthermore, in this embodiment, since the speed ratio pressure P8 is supplied to the chamber 136 of the second pressure regulating valve 102, there is an advantage that the second line oil pressure decrease amount increases as the speed ratio increases.

As is clear from the above, in this embodiment, the chamber 13 is
The speed specific pressure PQ supplied to chamber 6 is used as the depressurization pressure signal,
36 correspond to pressure signal receiving chambers for decompression, and
The atmospheric pressure supplied to the chamber 130 in connection with the operation of the second line oil pressure increase control valve 391 corresponds to a pressure increase oil pressure signal, and the chamber 130 corresponds to a pressure increase oil pressure signal receiving chamber.

Pll, Z-(8, ・Pta+W)/ (A 3-82
) ・ ・ ・ (3) PI3- [^4'
PLh÷−A, −P.

(82-AI)・Pll) / (8a-Az)
・ ・ ・ (4) Next, a lock-up quick release valve 400 provided to improve the release response of the lock-up clutch 36 is connected to a boat 402 a communicating with the clutch pressure oil passage 92 and a lock-up clutch pressure regulating valve 310 . A boat 1-402b communicates with the hydraulic chamber 316 on the end face of the plunger 317 via an oil passage 404, and a drain boat 40
2c, and a boat 402d that communicates with the engagement side oil passage 322 to the lock-up clutch 36, and a first position that is one end of the movement stroke and a second position that is the lower end. The spool valve element 406 is provided with a spool valve element 406 and a spring 408 that urges the spool valve element 406 toward the second position. When the forward clutch 54 is engaged and the fourth electromagnetic valve 346 is in the on state, clutch pressure Pcl is introduced into the chamber 410 on the lower end side of the spool valve element 406, and when the fourth electromagnetic valve 346 is in the off state, the pressure is exhausted. . Also, the upper end side of the spool valve 406 (spring 4
When the third electromagnetic valve 330 is in the on state, signal pressure Psoh3 (clutch pressure PcL) is introduced into the chamber 412 on the third electromagnetic valve 330 (08 side), and the pressure is exhausted when the third solenoid valve 330 is in the off state. The lock-up quick release valve 400 is controlled by the third solenoid valve 330 and the fourth solenoid valve 346, but only when the third solenoid valve 330 is in the off state and the fourth solenoid valve 346 is in the on state, the spool valve child 406 is positioned at the first position, and the clutch pressure PcL is set to the boat 402a, the boat 402
b. The clutch pressure Pct is raised via the oil passage 404 to the oil pressure chamber 316 of the lock-up clutch pressure regulating valve 310, and at the same time, the clutch pressure Pct is increased to the engagement side oil chamber of the fluid coupling 12 through the engagement side oil passage 322. Since the hydraulic oil discharged from the cooler 339 is drained from the upstream side of the cooler 339 via the boats 402d and 402C, the lock-up clutch 36 is rapidly released. Note that the third solenoid valve 330 and the fourth
When the solenoid valve 346 is in another state, the spool valve 406
is located in the second position. At this time, the engagement side oil chamber 3 of the fluid coupling 12 is activated by the lock-up quick release valve 400.
Not only is the flow resistance of the hydraulic oil discharged from the lock-up clutch 3 reduced, but also the clutch pressure PCI supplied to the release side oil chamber 35 of the fluid coupling 12 is increased by the lock-up clutch pressure regulating valve 310. 36 high release responsiveness is obtained.

The rehearse inhibit valve 420, which is provided to prohibit reverse during forward travel, is a boat 4.22 to which the third line hydraulic pressure P13 is supplied from the output boat 256 when the manual valve 250 is in the R range.
a, a slider bow I-422b that communicates with the hydraulic cylinder of the reverse brake 70 via an oil passage 423, and a drainbow 1-422c, and between the first position, which is the upper end of the movement stroke, and the second position, which is the lower end. A spool valve 424 is slidably disposed in the first
and a spring 426 that urges the device toward the position. In the chamber 428 on the upper end side of the j1 spool valve 424, an oil passage 430 is connected when the third solenoid valve 330 is in the on state.
A signal pressure PSO13 (clutch pressure PcL) is guided through the clutch, and is exhausted when the clutch is in the off state. The other end side of the spool valve 424 (chamber 4 of the spring 426 (lull)
32, there is a manual valve 250, and when it is in the S or L range, the third line oil pressure Pρ3 is the output boat 2.
It is introduced from 58. In the reverse inhibit +-=42o configured in this way, the third line oil pressure Pj2. is exhausted and a signal pressure P, is applied to the chamber 428. , 3 (clutch pressure PC,), and the spool valve element 424 is positioned at the second position (lower end), the communication between the boats 422a and 422b is cut off, and the reverse brake 70 Hydraulic oil supply to port 422c and boat 4 is cut off, and port 422c and boat 4
By communicating between 22b and 22b, the reverse brake 7
Since the hydraulic oil in the hydraulic cylinder No. 0 is drained, switching of the forward/reverse switching device 16 to reverse is prohibited. Therefore, while the vehicle is moving forward, the shift lever 252 is in the D position.
If there is an erroneous operation from the range to the R range past the N range, the third electromagnetic valve 330 is turned on by the electronic control device 460, which will be described later, and the forward/reverse switching device 16 is brought into the neutral state.

In FIG. 2, an electronic control device 460 functions as a control means of this embodiment, and includes a first solenoid valve 266, a second solenoid valve 268, and a third solenoid valve 330 in the hydraulic control circuit of FIG. , by driving the fourth solenoid valve 346, the speed ratio e of the CVT 14, the lock-up clutch 36 of the fluid coupling 12, etc. are controlled. Electronic control device 46
0 is equipped with a so-called microcomputer consisting of a CPU, RAM, ROM, etc., which includes a vehicle speed sensor 462 that detects the rotational speed of the drive wheels 24, and a vehicle speed sensor 462 that detects the rotational speed of the input shaft 30 and output shaft 38 of the C An input shaft rotation sensor 464 and an output shaft rotation sensor 46 that detect the speed, respectively.
6. Throttle valve opening sensor 468 for detecting the opening of the throttle valve provided in the intake pipe of the engine 10, operating position sensor 470 for detecting the operating position of the shift lever 252, and sensor for detecting the operation of the brake pedal. A signal representing the vehicle speed ■, a signal representing the input shaft rotation speed N = n, and an output shaft rotation speed N
A signal representing ut, a signal representing throttle valve opening θth,
Signal representing operating position P3 of shift lever 252, vibration
A signal representative of each operation is provided. 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 according to a program stored in advance in the ROM, and processes the first solenoid valve 266, the second solenoid valve 268, the third solenoid valve 330, A signal for driving the fourth solenoid valve 346 is output.

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

Ut, the speed ratio e of the CVT 14, the vehicle speed (2), etc. are calculated, and lock-up control of the lock-up clutch 36, speed change control of the CVT 14, etc. are sequentially or selectively executed according to the input signal conditions.

The speed change control of the CVT 14 is performed according to the flowchart shown in FIG. 21, for example. Step S
In 1, input signals etc. from each sensor are read, and based on the read signals, the vehicle speed ■,
The rotational speed N of the input shaft 38. , rotational speed N of the output shaft 54
. ut, throttle valve opening θ, and shift operation position WP9 are calculated.

In step S2, a predetermined relationship [N, ,
, ' = f (θ, V, P,), the target rotational speed N in of the input shaft 30 is determined based on the shift operation position P5, the throttle valve opening θ, and the vehicle speed V. For example, in order to generate the required output on the minimum fuel consumption rate curve of the engine 10 without changing the throttle valve opening θth, a plurality of sets of this relationship are determined in advance for each of the S and L ranges, and a functional formula or data map is used. RO in the form of
It is stored in advance in M. 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 in * is set higher so as to be on the deceleration side. Note that the shift operation positions for driving are not limited to the three positions of HIGH, S, and L ranges, but may be arbitrarily set as necessary.

In the subsequent step S3, the control deviation ΔN, . Then, in step S4, the above step S3
One of the plurality of speed change modes shown in FIG. 10 is selected based on the magnitude of the control deviation ΔN, □ determined in . This selection method is based on, for example, a control deviation Δ
A shift mode corresponding to the region including N i is selected. Among the multiple types of hatched areas in Figure 10, overlapping areas are provided between adjacent areas, but this prevents adjacent shift modes from being repeated alternately and resulting in unstable control. It's worthless.

If the control deviation ΔN i n takes a value within the overlap region, a shift state close to the current shift mode is selected. For example, the initial control deviation ΔN+, , is 25Orp.
When shift mode (b) is selected in m,
When the control deviation ΔN decreases to 14 Orpm and falls within the overlap between the shift mode (B) and the shift mode (C), the shift mode (B) is selected. Also,
Control deviation Δ from the state where shift mode (c) is selected
When N and 7 are included in the overlap between the shift mode (b) and the shift mode (c), the shift mode (c) is selected.

Then, in step S5, it is determined whether or not the shift mode (B) has been selected, and in step S6, it is determined whether or not the shift mode (BO) 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 D S2 of the second solenoid valve 268 is calculated according to the following equation (5). Ru. Also,
If the shift mode (bo) is selected in step S4, the determination in step S6 is affirmed, so
In step S8, the duty ratio of the second solenoid valve 268 is determined. is calculated according to the following equation (6).

D, 2=100%-KI・ΔN1. ．．・ ・ ・
(5) D-2-K2・ΔNi, ・・
-(6) However, K and 2 are constants.

Here, the reason why two types of equations (5) and (6) are used in determining the duty ratio Ds□ of the second electromagnetic valve 268 is that the flow rate characteristics of the flow rate control valve 264 are different. FIG. 22 shows a case where the shift mode (B) is selected, that is, the first solenoid valve 266 is in the ON state (deceleration shift).
The flow rate characteristics of the flow rate control valve 264 when the second
FIG. 3 shows the flow rate characteristics of the flow rate control valve 264 when the speed change mode (E) is selected, that is, when the first electromagnetic valve 266 is in the OFF state (increasing speed change). In addition,
22 and 23 show that the supply oil pressure is constant and that the two output boats 286b and 286e of the flow control valve 264 are
This is the characteristic obtained by determining the flow rate that passes through the directly connected oil path when the two are directly connected.

In this way, when the first solenoid valve 266 is in the on state, when the second solenoid valve 268 is in the on state, the flow rate control valve 264 is in the fully closed state, so the duty cycle is changed as shown in FIG. The flow rate decreases as the ratio DS□ increases, and conversely, when the first solenoid valve 266 is in the off state, when the second solenoid valve 268 is turned on, the flow control valve 264 is in the fully open state. Therefore, as shown in FIG. 23, the flow rate increases as the duty ratio D8□ increases. First solenoid valve 26
6 and the second solenoid valve 268, the duty ratio Ds2 determined as described above is set in step S9, which will be described later.
Alternatively, they are each driven in the on or off state determined in step S4. The duty drive of the second electromagnetic valve 268 is, for example, set in the on state for TD - DS□/100 hours within a certain period (period) T;
, · (]-D-2/l OO) is executed periodically such that the time is turned off. Here, the above (5
) and the duty ratio Ds determined by the equation (6).
2 increases the flow rate in proportion to the magnitude of the control deviation ΔN + n, thereby increasing the control deviation ΔN. Since the flow rate is controlled in a direction that eliminates
Alternatively, the flow rate control valve 264 is driven by the duty ratio Ds□ determined in S8 (step 512), thereby performing feedback control to match the target rotational speed N in* and the actual rotational speed N i n . It will be executed.

In step S9, each control executed by the third solenoid valve 330 and the fourth solenoid valve 346, namely lock-up clutch engagement and release control, lock-up clutch quick release control, accumulator back pressure control, reverse prohibition control,
A control mode determination routine for determining which control mode of the second line oil pressure reduction control is to be executed is executed. This control mode determination routine is shown in FIG. 24, for example.

Among the steps shown in FIG. 24, steps S31 to S
S7 is a part related to reverse prohibition control.

In step SSI, it is determined whether the vehicle speed ■ is equal to or greater than a constant vehicle speed value Cv1 stored in the ROM in advance. This judgment reference value Cvl is determined by the shock generated when the forward/reverse switching device 16 is switched to reverse.
This is set in advance to determine whether the vehicle speed is such that the transmission belt 44 of the VT 14 does not slip, and is set to a value of about 7 to 10 km/h, for example. In step SSI above, vehicle speed ■ is CV
When it is determined that the value is less than I, the contents of the flag XREV are set to zero (XRBV-0) in step SS2, and then, in step 333, it is determined whether the shift lever 252 is operated to the R range. If it has been operated, the flag XRE is set in step S7.
The content of V is assumed to be 1 (XREV-1). That is,
When driving is started in R range, XREV=O, but when driving is started in other than R range, χR
Therefore, EV=1.

When the vehicle speed V becomes equal to or higher than the predetermined vehicle speed value Cv+, the determination in step SSI is affirmed, and therefore, in step S34, it is determined whether or not the R range is being operated.

If the R range is not operated, there is no need to perform reverse prohibition control, so in step SS5 it is determined whether the N or P range is selected, and if the R range is selected, the lock-up clutch 36 is activated. The control mode (A) for release is selected. As shown in FIG. 25, in the control mode (A), both the third solenoid valve 330 and the fourth solenoid valve 346 are in the OFF state, and the lock-up clutch 36 is in the released state regardless of the vehicle speed. However, if it is determined in step SS5 that the range is other than the N or P range, that is, the forward range, step S39 is executed. However, if it is determined in step S84 that the vehicle has been operated into the R range, it means that the vehicle is traveling in reverse, so it is determined in step SS6 whether the content of the flag XREV is 1 or not. If XREV is -1, it is a continuous reverse range state, so step SS8 is executed, but if XREV is not 1, control mode (D) is selected. That is, steps SS1, SS4. , SS6 correspond to means for detecting that the shift lever 252 has been erroneously operated from the forward range to the R range during forward travel.

Here, if the vehicle is operated in the N range and then in the R range while driving in the D range at a relatively high vehicle speed equal to or higher than the vehicle speed value CVI, the determination in step SS6 is negative, and the reverse is reversed as described above. Prohibition control mode (D) is selected. As shown in FIG. 25, in the reverse prohibition control mode (D), the third solenoid valve 330 is in the on state and the fourth solenoid valve 346 is in the off state, so by executing this mode, Even in the R range, the supply of hydraulic oil to the reverse brake 70 is blocked by the rehearse inhibit valve 420, and switching of the forward/reverse switching device 16 to reverse is prohibited.

In addition, when you start driving backwards in R range and the vehicle speed becomes equal to or higher than CVI, or when the vehicle speed is equal to or higher than CVI and you first operate N range and then operate R range again, XREV-1 Therefore, since the determination in step SS6 is affirmative, the process proceeds to step SS8, and finally the accumulator back pressure control mode (C) or the lock-up clutch release control mode (A) is selected. In this control mode (C) or (A), the third solenoid valve 330
is turned off, the forward/reverse switching device 16 is allowed to switch to reverse.

If the reverse prohibition control is not in effect and the N or P range is not in effect, step SS8 is performed when the R range is selected.
is executed, the input shaft (output shaft 38) and output shaft 58 in the forward/reverse switching device 16 are adjusted according to the following equation (7).
The rotational speed difference Nd is calculated, and in the case of a forward range such as the D, S, or L range, step SS9 is executed to calculate the rotational speed difference Nd according to the following equation (8) 2.

Nd-INout-12・N2c1 ・ ・ ・(7
)Nd=1N,,L-N,cl --(
8) Here, N out is CVTl, output shaft 3 of 4
8 rotational speed, N pc is the rotational speed of the carrier 60 of the forward/reverse switching device 16, and ip is the rotational speed of the carrier 60 of the forward/reverse switching device 16 when going backwards.
The gear ratio is The above N p c has a completely one-to-one correspondence with the vehicle speed V, and is obtained according to the following equation (9). Further, the above jp is N when the reverse brake 70 is completely engaged. From U, and N pc, the following formula 0
0).

Npc=C/V ・ ・ ・(9) i p
= Nout/Npc...(IQ) However, C is a constant.

The rotational speed difference Nd obtained as described above is obtained in step S S1. At step O, it is determined whether or not the value is larger than a determination reference value C9 stored in advance in the ROM. This determination reference value CN is a value for determining whether engagement of the forward clutch 72 or the reverse brake 70 has been completed, and is, for example, a value of about 30 rpm. In step 5SIO above, if it is determined that the rotational speed difference Nd is not larger than the judgment reference value C9, the engagement is in the completed state, so steps S S 1.2 and below are executed, but if it is determined that the rotational speed difference is large If so, step 5SI
In I, N or P range, S, or ■7
It is determined whether the elapsed time since the shift to the range has exceeded a determination reference value C7 stored in advance in the ROM. This judgment reference value CT is a value for determining that the engagement time of the forward clutch 72 or the reverse brake 70 has exceeded the normal time, and is slightly longer than the time required for the normal engagement to end. It is determined to be a large value. Step 5S
In II, if it is determined that the elapsed time has not exceeded the judgment reference value CT, steps 5S12 and subsequent steps are executed, but if it is determined that the elapsed time has exceeded the judgment reference value CT, the accumulator back pressure is Control mode (C) is selected. Note that this accumulator back pressure control mode (
In C), as can be seen from FIG. 25, the solenoid valve 330 is turned off, so the second line oil pressure increase control is also performed.

If the determination in step 5SIO or 5SII is negative and the control mode (C) is not selected, it is determined in step 5S12 whether or not the R range is selected, and if the R range is the lock-up clutch release control mode (A ) is selected immediately. This prevents the third solenoid valve 330 from being turned on in the R range state, resulting in reverse prohibition control and the vehicle becoming unable to travel.

If it is determined in step 5S12 that the vehicle is not in the R range, it is determined in step 5S13 whether the brake switch 472 is on or not, and the vehicle speed V is stored in the ROM in advance in step S S ], 4. It is determined whether or not the value is lower than the determined criterion value Cv2. This determination reference value Cv□ is a value for determining release of the lock-up clutch 36 and increase control of the second line oil pressure Pffi2 in the operating state of the brake, and for example, a value of about 40 km/h is adopted.

In steps 5S13 and 5S14, if it is determined that the brake switch 472 is on and the vehicle speed is lower than CV2, that is, if the release condition for the lock-up clutch 36 is satisfied, the lock-up clutch release control is performed. Step 5S21 and subsequent steps for selecting mode (A) or lock-up clutch quick release control mode (B) are executed. In step SS21,
A control mode in which the current control mode maintains the lock-up clutch 36 in a released state without sudden release (A, )
Or (C) is determined.

If the judgment is affirmative, the normal lock-up clutch release control mode (A) is selected, but if the judgment is negative, it is determined in step 5S22 whether or not the current control mode is the release control mode (B). be judged. If it is determined that the current control mode is not (B), the contents of the timer counter XLC are cleared to zero in step 5S24, and then the quick release control mode (B) is selected. If it is determined that the release control mode (B) is selected, the timer counter XLC is set in step 5S23.
After 1 is counted, in step 5S25, it is determined whether the count content of the timer counter XLC has reached the determination reference value C5 stored in advance in the ROM. If it has not yet been reached, the quick release control mode (B) will continue to be selected, but if it has been reached, it will be switched to the control mode (A). In this way, since the sudden release control control mode (B) is maintained for a short period of time corresponding to the judgment reference value Cs, the engagement side oil chamber 3
3 is drained by the lock-up quick release valve 400, the internal pressure of the fluid coupling 12 is reduced, and the generation of air bubbles within the fluid coupling 12 is eliminated as much as possible. The criterion value C5 is set smaller than the value corresponding to the time required to generate bubbles within the fluid coupling 12 in this way.

If it is determined in steps 5S13 and 5S14 that the brake switch 472 is not in the on state,
Alternatively, even if the brake switch 472 is in the ON state, if it is determined that the vehicle speed ■ is equal to or higher than the determination reference value Cv□, the current control mode is set to the control mode (A) in which the lock-up clutch 36 is released. ,
It is determined whether it is either (B) or (C).

Steps 5S15 to 5S19 are for determining whether the lock-up clutch 36 is engaged or released. If the judgment in step 5S15 is affirmative, in step 5SIB the input shaft rotational speed N i
It is determined whether n is larger than a predetermined determination reference value M L 2. If it is determined that the vehicle speed V is greater than 7, then in step 5S19 the vehicle speed
It is determined whether or not the value is larger than the determination reference value Cv4 stored in the OM. If it is determined that the vehicle speed V is greater than the determination reference value Cv5 stored in advance in the ROM, it is determined in step 5S20, and if it is greater than the determination reference value CvS, the second line oil pressure reduction control is performed. Mode (E) is selected, and if it is less than or equal to the determination reference value Cvs, reverse prohibition control mode (D) is selected. The second line oil pressure reduction control mode (E) and reverse prohibition control mode (D) are control modes in which the lock-up clutch 36 is engaged because the third solenoid valve 330 is turned on. In addition, steps 5S18 and 5S above
If the determination in step 19 is negative, the normal lock-up clutch release control mode (A) is selected, so that the released state of the lock-up clutch 36 is maintained.

On the other hand, if it is determined in step S S1.5 that the current control mode is not one of (A), (B), and (C), then in step S16 the input shaft rotational speed N in is set to a predetermined value. It is determined whether the vehicle speed is larger than the determination reference value M, 1, and in step 5S17, the vehicle speed is determined to be greater than the determination reference value CV3 stored in the ROM in advance.
It is determined whether or not it is larger than . Above step 5S1
If the judgments in steps 6 or 5S17 are negative, the normal lock-up clutch release control mode (A) is selected, but if the judgments in steps 5S16 and 5S17 are both affirmative, steps 5S20 and subsequent steps are executed. , since the second line oil pressure reduction control mode (E) is selected when the vehicle speed V is greater than the judgment reference value Cvs,
The third solenoid valve 330 and the fourth solenoid valve 346 are turned on, and the second line oil pressure Pj22 is lowered. However, in step 5320, the vehicle speed ■ is the judgment reference value C.
Reverse prohibition control mode (D) is selected when the second line oil pressure is below VS, and the second line oil pressure PI! , 2 are controlled to normal values.

Therefore, in steps 5SI5 to 5SI9 above, when the lock-up clutch 36 is released, N + > M +, 2 and V
>Cv4, the lock-up clutch 36 is engaged. In addition, when the lock-up clutch 36 is engaged, N, , <M,
, or if V<Cv3, lock amplifier clutch 36
is released. Here, the above judgment criterion (I
M L I and M L □ are determined based on the throttle valve opening θL6 from functions stored in the ROM in advance, and have a relationship that increases as the throttle valve opening θtb increases. . Also, if the throttle valve opening θ is the same, ML is adjusted to prevent control fluctuations.
I>ML2. In addition, the above judgment reference value Cvf
f and Cv4 have values of about 20 km/h, and Cv3>Cv4 for them as well.

Returning to FIG. 21, when one of the control modes (A), (B), (C), (D), and (E) is determined as described above in step S9, step S] At step O, it is determined whether the control mode is (C). If it is determined that the control mode is (C), step 51
．． Step S1.2 is executed after the duty ratio D S4 is determined in Step S1.1, but when the control mode is (C)
If it is determined not to be the case, step 312 is directly executed.

The duty ratio Ds4 is determined so that when the forward clutch 72 or the reverse brake 70 is engaged, it is controlled to generate back pressure in the accumulators 342 and 340 to ensure smooth engagement. Duty ratio D during forward shift and reverse shift! 4 is, for example, the input shaft rotational speed N8.4 at the time of shifting. , and the elapsed time t since the shift, etc., are determined sequentially in accordance with functions for forward shifting and backward shifting stored in advance in R and OM, respectively. Figure 26 shows when the vehicle is stopped (N, C
- Duty ratio D□ when N-D shifted at )
and output shaft rotation speed N. It shows the change over time of U. Then, in step S12, step S
4 and S9, the first solenoid valve 266, second solenoid valve 268, and third solenoid valve 330 correspond to each control mode determined in S9.
, and a drive signal is output so that the fourth solenoid valve 346 is turned on or off.

As described above, in the hydraulic control circuit of this embodiment, the second line hydraulic pressure P supplied to the secondary hydraulic cylinder 56 (the driven hydraulic actuator in the positive torque running state)
ffi. The spool valve 110 regulates the pressure of the spool valve 110, and the second line oil pressure pI! , zM A chamber 136 for receiving a pressure reducing hydraulic pressure signal (P8) for generating a biasing force in the direction of a small force, and a pressure increasing chamber 136 for generating a biasing force in the upward direction of the second line hydraulic pressure Pffi2 in the spool valve element 110. A second pressure regulating valve 102 is provided with a chamber 130 that receives a hydraulic pressure signal (atmospheric pressure), and when the vehicle speed exceeds a predetermined judgment reference value Cv5, the pressure reducing hydraulic signal is transmitted to a chamber 13.
6, and also supplies the pressure-increasing hydraulic signal to the chamber 130 in connection with the release of the lock-up clutch 36 when the vehicle speed V falls below a predetermined judgment reference value Cvz. ing.

Therefore, when the vehicle speed ■ exceeds a predetermined value Cv5, the hydraulic pressure signal generating means generates a pressure reducing hydraulic signal, and the second hydraulic pressure signal is supplied to the secondary hydraulic cylinder 56.
Since the line hydraulic pressure Pn2 is reduced as shown in FIG. 20, the tension of the transmission belt 44 is prevented from becoming excessive based on the centrifugal hydraulic pressure generated in the secondary side hydraulic cylinder 56, and the transmission belt 44 has a long life. Sexuality is enhanced. Further, when the lock-up clutch 36 is released due to the vehicle speed becoming low and falling below Cv Since the speed ratio is increased, the speed ratio can be quickly changed to the maximum speed increase side when the vehicle suddenly stops. Furthermore, since a pressure control servo valve equipped with a linear solenoid is not used in the second pressure regulating valve 102, the hydraulic control device becomes inexpensive. Here, in this embodiment, the second line oil pressure reduction control mode (
E), lock-up release control mode (A) that increases the second line oil pressure P2□, lock-up sudden release control mode (B), or accumulator back pressure control mode (C).
an electronic control device 460 that selects the control mode; a third solenoid valve 330 and a fourth solenoid valve 346 that are driven when those control modes are selected; a second line oil pressure reduction control well 380;
The second line oil pressure increase control valve 391 and the like correspond to the oil pressure signal generating means.

Next, another embodiment of the present invention will be described. In the following description, the same parts as in the above-mentioned embodiments are given the same reference numerals, and the description thereof will be omitted.

In the example shown in FIG. 27, the speed specific pressure Po is supplied to the bow 482a of the second line oil pressure increase control valve 391, and the hydraulic pressure P in the secondary hydraulic cylinder 56 is supplied to the bow 484a. 0. Alternatively, the second line oil pressure Pj22 is supplied. In addition, the second line oil pressure reduction control well 380
The spool valve element 393 is driven in accordance with the signal pressure P8.4 controlled by the fourth solenoid valve 346. As a result, the third solenoid valve 330 is in the OFF state and the signal pressure Psol3 is set to the second line oil pressure increase control valve 39.
1, the second pressure regulating valve ]02 is supplied to the chambers 130 and 13 of the second pressure regulating valve ]02 regardless of whether the fourth solenoid valve 346 is on or off.
6 are both released to the atmosphere, and the second line oil pressure pH2 is increased from the normal value. When the third solenoid valve 330 is turned on and the signal pressure P8.3 is supplied to the second line oil pressure increase control valve 391, the chamber 136 of the second pressure regulating valve 102
to the hydraulic pressure P in the secondary hydraulic cylinder 56. ut or 2nd line hydraulic PI! , 2 are supplied. In this state, if the signal pressure P5OL4 is not supplied, the second pressure regulating valve 1
P in room 136 of 02. Since ut or Pff2 is not supplied, the second line oil pressure PI! , 2 are controlled to normal values. However, the signal pressure P8°, 4° due to the fourth solenoid valve 346
is generated, the second line oil pressure drop control well 380
Since Pout or PI3 is supplied through the second m-pressure valve 102 (7) chamber 136, the second line oil pressure PI2 is lowered from the normal value. In this embodiment as well, the same effects as in the embodiment shown in FIG. 1 described above can be obtained. In addition, in this embodiment, the atmospheric pressure supplied to the chamber 130 corresponds to the pressure increasing hydraulic pressure signal, and the atmospheric pressure P supplied to the chamber 136 corresponds to the pressure increasing oil pressure signal. at or PI
! , z correspond to the hydraulic pressure signal for pressure reduction.

In the example shown in FIG. 28, boats 482a, 482b, 4
82c, the plunger 116 of the second pressure regulating valve 102
Boat 483 connected to chamber 502 provided on the side
A and a drain boat 483b are provided, and a clutch hydraulic pressure Pcl guided by an oil passage 92 is supplied to the boat 394a. Chamber 502 of the second pressure valve 102
is provided to cause the plunger 116 to urge the spool valve element 110 of the second pressure regulating valve 102 in the direction of increasing the second line oil pressure P2□ when the clutch oil pressure PcL is supplied. Further, the chamber 130 of the second pressure regulating valve 102
is constantly supplied with speed specific pressure P8. This results in
The third solenoid valve 330 is in the off state and the signal pressure P sol
, 3 are not supplied to the second line oil pressure increase control valve 391, regardless of whether the fourth solenoid valve 346 is on or off.
At the same time as the chamber 136 of the second pressure regulating valve 102 is released to the atmosphere, the clutch hydraulic pressure PET is supplied to the chamber 502, and the second line hydraulic pressure PI! , 2 are added by a predetermined amount from the normal value.

However, when the third solenoid valve 330 is turned on, the signal pressure P5oL3 increases to the second line oil pressure increase control valve 391.
When the clutch oil pressure Pet is supplied to the second line oil pressure reduction control well 380, the clutch oil pressure Pet is supplied to the second line oil pressure reduction control well 380, and the second pressure regulating valve 1
Since the clutch oil pressure PcL in the 02 chamber 502 is exhausted, the second line oil pressure P12 is controlled to the normal value when the signal pressure P5o14 is not supplied.
011 is supplied, the clutch hydraulic pressure PcL is supplied to the second pressure regulating valve 1020 chamber 136, so the second line hydraulic pressure P
ffi, is reduced from its normal value. In this embodiment as well, the same effects as in the embodiment shown in FIG. 1 described above can be obtained.

In this embodiment, the clutch oil pressure PcL supplied to the chamber 502 corresponds to the pressure increase oil pressure signal, the chamber 502 corresponds to the pressure increase oil pressure signal receiving chamber, and the clutch oil pressure Pet supplied to the chamber 136 corresponds to the pressure reduction oil pressure signal. Compatible with hydraulic signals.

In FIG. 29, the one-dot chain line indicates the second line oil pressure PI! in the embodiment shown in FIGS. 27 and 28. ,2
, and the two-dot chain lines indicate respective decrease control values.

In the embodiment shown in FIG. 30, one second line oil pressure increase/decrease control valve 514 controls the increase and decrease of the second line oil pressure Pρ2 of the second pressure regulating valve 102. That is, the 28th jl pressure valve 102 has a plunger 510 that can come into contact with one end of the spool valve 110, and a chamber 1 with the plunger 510 in between.
．． 30 and a chamber 512 located on the opposite side. The second line oil pressure increase/decrease control valve 514
Boat 51 to which the speed specific pressure P8 guided by 6 is supplied.
6a, drain boat 516b, boat 516c to which signal pressure Psol is supplied, chamber 517, second pressure regulating valve 10
Boats 51 and 6d are connected to the chamber 130 of the second pressure regulating valve 102, and boats 1-516e are connected to the chamber 512 of the second pressure regulating valve 102.
and a spool valve 51 that switches the connection between the boats.
8 and a spring 520 for biasing the spool valve element 518 in one direction. As a result, when the third solenoid valve 330 is in the off state and the fourth solenoid valve 346 is in the on or off state, the spool valve element 518 is moved according to the biasing force of the spring 520, so that the chamber 1
30 and 512 are both at atmospheric pressure, and the second line oil pressure Pρ2 is at the normal value (dashed line) as shown by the solid line in Fig. 31.
It is raised from Further, when the third solenoid valve 330 is in the on state, the signal pressure P is applied to the end surface of the spool valve element 518.
sol, 3 acts.

Therefore, the third solenoid valve 330 is in the on state and the fourth
When II4t-346 is in the off state, spool valve 5
18 is moved against the biasing force of the spring 520, the speed specific pressure P8 is supplied to the chamber 130 of the second pressure regulating valve 102, the chamber 512 is brought to atmospheric pressure, and the second line oil pressure Plz is increased to the above-mentioned level. The normal value is shown by the broken line in FIGS. 31 and 32. And the third solenoid valve 330
When both the fourth electromagnetic valve 346 and the fourth solenoid valve 346 are in the on state, the spool valve element 518 is moved according to the biasing force of the spring 520, so that the chamber 130 of the second pressure regulating valve 102 is brought to atmospheric pressure, and the pressure in the chamber 512 is increased. Signal pressure P. ,
3 is supplied, and the second line oil pressure PN2 is lowered as shown by the solid line in FIG.

In this embodiment as well, the same effects as in the above-mentioned embodiments can be obtained. In this embodiment, the atmospheric pressure supplied to the chamber 130 corresponds to the pressure increasing hydraulic pressure signal, the signal pressure P5oL3 supplied to the chamber 512 corresponds to the pressure reducing hydraulic pressure signal, and the chamber 512 corresponds to the pressure reducing hydraulic pressure signal receiving pressure. Each corresponds to a room.

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 shown in FIG. The oil pressure P out in the side hydraulic cylinder 56 or the second line oil pressure Pβ2 may be supplied.

Further, in the embodiment shown in FIG. 1 described above, the chamber 160 of the first pressure regulating valve 100 was opened to the atmosphere, but N.

In order to suppress belt noise by lowering the first line oil pressure PN by a predetermined pressure when in the P range, the manifold j.

A first line oil pressure reduction control valve is provided that biases the spool valve element 140 in the valve opening direction by supplying a second line oil pressure Pj22 into the chamber 160 in relation to the output oil pressure from the valve 250. You can.

Further, in the above embodiment, the speed change control valve device 260 controls the primary hydraulic cylinder 54 and the secondary hydraulic cylinder 56.
The speed ratio of the CVT 14 was changed by simultaneously supplying hydraulic oil to one side and simultaneously discharging hydraulic oil from the other side. The hydraulic control circuit is of a type in which the speed ratio of the CVT 14 is changed by constantly supplying hydraulic oil to the primary hydraulic cylinder 54 or discharging hydraulic oil from the primary hydraulic cylinder 54 using a speed change control valve. Good too.

Further, the speed change control valve device 260 of the above-described embodiment was composed of a speed change direction switching valve 262, a flow rate control valve 264, etc., but it is composed of a four-way valve that can continuously control the flow rate using a linear solenoid. Good too.

Further, in the above-described embodiment, the throttle valve opening detection valve 18
Throttle pressure P generated by 0 was used, but in vehicles that do not use a throttle valve, such as vehicles equipped with diesel engines, hydraulic pressure corresponding to the amount of accelerator pedal operation is used. Bye. 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.

In addition, in the shift control of CVT], 4 in the above-described embodiment, the target rotational speed N,. ' is the actual input shaft rotation speed N,
7 were controlled to match, but the speed ratio e = N
Since ou t / N H7, the target speed ratio e*
This is substantially the same even if the speed ratio e is controlled so as to match the actual speed ratio e.

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

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

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

[Brief explanation of the drawing]

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 leap diagram showing the 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 views for explaining the relationship between the speed ratio of the CVT shown in FIG. 2 and the oil pressure values of each part, and FIG.
Figure 2 shows the engine brake running state, and the 13th figure shows the no-load running state. FIG. 14 is a diagram showing the output characteristics of the first pressure regulating valve of FIG. 4 with respect to the primary hydraulic cylinder internal oil pressure or the second line oil pressure. FIG. 15 is a diagram showing the change characteristics of the duty ratio of the fourth electromagnetic valve and the oil pressure that is continuously changed in relation to the duty ratio in the hydraulic circuit of FIG. 1. 16th
The figure is a diagram illustrating in detail the solenoid pressure switching valve, the fourth pressure regulating valve, etc. of the hydraulic control circuit of FIG. 1. FIG. 17 is a diagram showing the change characteristics of the duty ratio of the fourth electromagnetic valve and the fourth line oil pressure that is continuously changed in relation to the duty ratio in the hydraulic circuit of FIG. 1. FIG. 18 is a chart illustrating operating conditions for increasing and decreasing the second line oil pressure in the embodiment shown in FIG. FIG. 19 is a diagram showing output characteristics during upper limit control of the second line oil pressure in the embodiment shown in FIG. 1, and FIG. 20 is a diagram showing output characteristics when controlling the second line oil pressure to decrease in the embodiment shown in FIG. FIG. FIG. 21 is a flowchart illustrating the operation of the electronic control device of FIG. 2. FIGS. 22 and 23 are diagrams showing the relationship between the duty ratio of the second solenoid valve and the flow rate that is continuously changed in relation to the duty ratio, and FIG. FIG. 23 shows the characteristics when the speed ratio of the CVT is changed in the speed increasing direction. The 24th time is a flowchart illustrating the routine that constitutes step S9 in FIG. 21. Figure 25 shows control modes (△), (B), (C), (D), (E
) is a diagram showing the operating states of the third solenoid valve and the fourth solenoid valve. FIG. 26 is a time chart showing the duty ratio of the fourth solenoid valve and the output shaft rotational speed of the CVT during a shift. FIGS. 27 and 28 are diagrams each illustrating the main parts of a hydraulic control device in another embodiment of the present invention. FIG. 29 is a diagram showing the second line oil pressure increase and decrease control characteristics in the embodiments of FIGS. 27 and 28. FIG. 30 is a diagram showing essential parts of a hydraulic control device in another embodiment of the present invention. FIGS. 31 and 32 are diagrams respectively showing the characteristics during the increase control and the characteristics during the decrease control of the second line oil pressure in the embodiment of FIG. 30. 330: Third solenoid valve (hydraulic signal generating means) 346: Fourth
Solenoid valve (hydraulic signal generation means) 380: 2nd line oil pressure reduction control valve 391: 2nd line oil pressure increase control valve

Claims (1)

[Claims] A pair of variable pulleys provided on the primary rotation shaft and the secondary rotation shaft, a transmission belt wound between the pair of variable pulleys, and an effective diameter of the pair of variable pulleys. In a vehicle belt-type continuously variable transmission equipped with a pair of hydraulic actuators that respectively change the transmission belt, the transmission belt is adjusted by directly or indirectly regulating the hydraulic pressure in the driven hydraulic actuator of the pair of hydraulic actuators. A hydraulic control device of the type that controls tension, comprising a spool valve element for regulating the hydraulic pressure in the driven side hydraulic actuator, and a device for applying a biasing force to the spool valve element in the direction of decreasing the pressure regulation value. a pressure reducing oil pressure signal receiving chamber for receiving a pressure reducing oil pressure signal; and a pressure increasing oil pressure signal receiving chamber for receiving a pressure increasing oil pressure signal for applying a biasing force to the spool valve in the direction of increasing its pressure regulation value. When the vehicle speed exceeds a predetermined range, the pressure-reducing oil pressure is generated and supplied to the pressure-reducing oil pressure signal receiving chamber, and when the vehicle speed falls below the predetermined range, the pressure-reducing oil pressure is increased. A hydraulic control device for a belt-type continuously variable transmission for a vehicle, comprising: a hydraulic signal generating means for generating a hydraulic pressure signal for boosting and supplying the signal to a pressure-increasing hydraulic signal receiving chamber.