JPH02271149A - Hydraulic controller for belt type continuously variable transmission for vehicle - Google Patents

Abstract

PURPOSE:To prevent the excessive tension of a transmission belt by judging if the travelling state is within a region in which the hydraulic pressure in a driven side hydraulic actuator is to be decompressed or not, on the basis of the demanded output value, engine revolution speed, and car speed and controlling a pressure adjusting valve. CONSTITUTION:An electronic controller 460 receives the signals of a car speed sensor 462, input/output shaft revolution sensors 464 and 466, throttle opening degree sensor 468, etc., and it is judged if the travelling state of a vehicle is within a region in which the hydraulic pressure into a driven side hydraulic actuator 56 is to be decompressed or not, on the basis of the demanded output value of the vehicle, engine revolution speed, and car speed. When it is judged that the travelling state is within a decompression region, a solenoid valve 346 as decompression signal generating means is operated, and a decompression hydraulic signal is supplied into the chamber of a pressure adjusting valve in a hydraulic control circuit. Therefore, on the basis of the centrifugal hydraulic pressure generated in a driven side hydraulic actuator, the excessive increase of the tension of a transmission belt can be prevented.

Description

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

Conventional technology A pair of variable pulleys provided on a primary rotating shaft and a secondary rotating shaft, a transmission belt that is wound around the pair of variable pulleys to transmit power, and an effective diameter of the pair of variable pulleys. A belt-type continuously variable transmission for a vehicle is known, which includes a pair of hydraulic actuators that respectively change the transmission speed. For example, the belt-type continuously variable transmission described in Japanese Patent Application Laid-Open No. 52-98861 is one such example. In the hydraulic control device installed in such a belt-type continuously variable transmission,
A hydraulic control circuit is provided with a pressure regulating valve that controls the tension of the transmission belt as necessary and sufficiently by regulating the hydraulic pressure in the driven hydraulic actuator of the pair of hydraulic actuators according to the transmitted torque and speed ratio. . In this type of hydraulic control circuit, it is inevitable that centrifugal hydraulic pressure will be generated in the driven hydraulic actuator as the secondary variable pulley rotates, especially when the vehicle is running at high speed.
Based on this centrifugal oil pressure, the tension in the transmission belt becomes excessive, and there is a risk that durability may 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 oil pressure generated based on this rotational speed is detected. At the same time, the centrifugal oil pressure is subtracted from the pressure regulation target value, and a pressure control servo valve equipped with a linear solenoid is driven to obtain the corrected pressure regulation target value, and the line oil pressure to be supplied to the driven side hydraulic actuator is calculated. A hydraulic control device is provided that continuously adjusts the pressure.

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 excessive tension in the transmission belt based on the centrifugal hydraulic pressure generated in the driven side hydraulic actuator, and to provide a highly reliable and inexpensive hydraulic control device. .

Means for Solving the Problems The gist of the present invention for achieving the object is: - a pair of variable pulleys provided respectively on the downstream rotating shaft and the secondary rotating shaft; In a vehicle belt-type continuously variable transmission comprising a power transmission belt wound between variable pulleys 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; (b) a pressure regulating valve having a chamber for receiving a pressure reducing hydraulic signal for applying a biasing force to the spool valve element in the direction of decreasing the pressure regulating value;
(C) determining means for determining whether or not the running state of the vehicle is within a range in which the hydraulic pressure in the driven side hydraulic actuator should be reduced, based on a required output value of the vehicle, an engine rotation speed, and a vehicle speed; When the determination means determines that the running state of the vehicle is within the range, the pressure reduction oil pressure signal generation means generates the pressure reduction oil pressure signal and supplies the pressure reduction oil pressure signal to the pressure regulating valve chamber. be.

Operation and Effects of the Invention With this structure, when the determination means determines that the vehicle state is within the range, the pressure reduction oil pressure signal generation means generates the pressure reduction oil pressure signal, and the pressure reduction valve is activated. Since the pressure is supplied to the chamber, the pressure regulating valve reduces the pressure in the driven side hydraulic actuator. This prevents the tension in the transmission belt from becoming excessive based on the centrifugal hydraulic pressure generated in the driven-side hydraulic actuator. 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.

Moreover, in the pressure reduction control, it is determined whether the running state of the vehicle is within a range in which the hydraulic pressure in the driven side hydraulic actuator should be reduced based on the required output value, engine rotation speed, and vehicle speed of the vehicle. Therefore, the tension of the transmission belt can be controlled more appropriately than a hydraulic control device that reduces the pressure depending on whether the vehicle speed exceeds a certain reference value. In other words, since the actual output torque of the engine depends not only on the throttle valve opening but also on the engine rotation speed, the pressure regulation value is determined from the throttle valve opening and the speed ratio, and the pressure reduction oil pressure signal is generated. If the reference value for determining the transmission torque is constant, the hydraulic pressure in the driven side hydraulic actuator of the belt-type continuously variable transmission will not be the optimum value for the transmitted torque, and the pressure regulation value will be higher overall. However, according to the present invention, since it is determined whether the vehicle state is within the above range by further considering the engine rotation speed and the required output value, the pressure of the oil pressure applied to the driven side hydraulic actuator is adjusted. The value and the tension of the transmission belt are appropriately controlled.

Note that the driven-side 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. It shows a hydraulic actuator.

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

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

The fluid coupling 12 connects the pump impeller 28 connected to the crankshaft 26 of the engine 10 and the input shaft 3 of the CVT l4.
a turbine impeller 32 fixed at zero and rotated by oil from the pump impeller 28; a lock-up clutch 36 fixed to the input shaft 30 via a damper 34;
An engagement side oil chamber 33 connected to a maintenance side oil passage 32.2, which will be described later.
and a release side oil chamber 35 connected to a release side oil passage 324, which will be described later. The inside of the fluid coupling 12 is always filled with hydraulic oil. 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 engagement side oil chamber 33 and the release side oil is supplied. Room 35
As the hydraulic oil flows out, the lock-up clutch 36 is engaged, and the crankshaft 26 and the input shaft 30 are directly connected. On the contrary, 1. When the vehicle speed etc. become below a predetermined value, hydraulic oil is supplied to the disengagement side oil chamber 35 and hydraulic oil is flowed out from the engagement side oil chamber 33.
Lock-up clutch 36 is released.

CVTl, 4 has variable pulleys 40 and 42 of the same diameter provided on its input shaft 30 and output shaft 3, respectively;
The transmission belt 44 is wound around the variable pulleys 40 and 42.

The variable pulleys 40 and 42 are fixed rotating bodies 46 and 48 fixed to the input shaft 30 and the output shaft 38, respectively, and are provided on the input shaft 30 and the output shaft 38 respectively so as to be movable in the axial direction but not relatively rotatable around the axes. The movable rotating bodies 50 and 52 are
is moved by the primary hydraulic cylinder 54 and secondary hydraulic cylinder 56 that function as hydraulic actuators, thereby changing the V-groove width, that is, the hanging diameter (effective diameter) of the transmission belt 44, and the speed ratio e (
=Rotational speed N of the output shaft 38. The rotational speed N5, ) of the input shaft 30 is changed. Since the variable pulleys 40 and 42 have the same diameter, the hydraulic cylinders 54 and 56 have similar pressure receiving areas. 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 hydraulic pressure P2□, which is regulated by a second pressure regulating valve 102 described later, is on the driven side. By being supplied to the side hydraulic cylinder, the transmission belt 44 is maintained at an optimum belt tension within a range where slippage does not occur.

The forward/reverse switching device 16 is a well-known double pinion type planetary gear mechanism, and includes a pair of planetary gears 62 and 64 that are rotatably supported by a carrier 60 fixed to an output shaft 58 and mesh with each other. Advance switching device 1
A sun gear 66 that is fixed to the input shaft (output shaft of the CVT l4) 38 of No. 6 and meshes with the planet gear 62 on the inner circumference side, a ring gear 68 that meshes with the planet gear 64 on the outer circumference side, and a reverse gear for stopping the rotation of the ring gear 68. brake 70, the carrier 6o, and the input shaft 38 of the forward/reverse switching device 16.
A forward clutch 72 is provided to connect the forward drive clutch 72 and the forward drive clutch 72. The reverse brake 70 and the forward clutch 72 are hydraulically operated friction engagement devices, and when they are not engaged, the forward/reverse switching device 16 is in a neutral state and power transmission is cut off. . However, when the forward clutch 72 is engaged, the output shaft 38 of the CVT 14 and the output shaft 58 of the forward/reverse switching device 16 are directly connected, and power in the forward direction of the vehicle is transmitted. In addition, the reverse brake 70
When engaged, the rotational direction is reversed between the output shaft 3 of the CVTI 4 and the output shaft 5 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 hydraulic oil that has returned to an oil tank (not shown) through a strainer 76, and also sucks hydraulic oil that has been returned through a suction oil passage 78 and pumps it to a 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. First line oil pressure Pf in oil passage 80! , , are pressure regulated. In addition, the first line oil pressure P! is controlled by the second pressure regulating valve 102 of the pressure reducing valve type. .

By reducing the pressure, the second line oil pressure P12 in the second line oil passage 82 is regulated.

First, the configuration of the second pressure regulating valve 102 will be explained. As shown in FIG. 3, the second pressure regulating valve 102 includes a spool valve 11 that opens and closes between the first line oil passage 80 and the second line oil passage 82.
0, spring seat 112, return spring 11
4. It is equipped with a plunger 116. Further, at the shaft end of the spool valve element 110, a first land 1 with a diameter increasing in order is provided.
18, a second land 120, and a third land 122 are formed in this order. A chamber 126 is provided between the second land 120 and the third land 122, into which the second line oil pressure Pρ2 is introduced as a feedback pressure through the throttle 124, and the spool valve element 110 is connected to the second line oil pressure PJ2. The valve is biased toward the valve closing direction. Further, on the end surface side of the first land 118 of the spool valve 110, a throttle 1 is provided.
A chamber 130 is provided through which a speed specific pressure Pe, which will be described later, is introduced, and the spool valve element 110 is urged in the valve closing direction by the speed specific pressure Pe.

Inside the second pressure regulating valve 102, the return spring 11
A biasing force of 4 in the valve opening direction is applied to the spool valve element 110 via the spring seat 112. Further, a chamber 132 for applying a throttle pressure Ptb (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 first land 1
18, the cross-sectional area of the second land 120 is A2, the cross-sectional area of the third land 122 is A3, the pressure receiving area of the plunger 116 is Aa, and the return spring 11
If the biasing force of 4 is W, the spool valve 110 is calculated by the following formula (
Equilibrium is achieved at the position where 1) holds true. That is, by moving the spool valve 110 according to equation (1), the first valve guided to the boat 134a
A state in which the hydraulic oil in the line oil passage 80 is made to flow into the second line oil passage 82 via the boat 134b and the boat 13
The state in which the hydraulic oil in the second line oil passage 82 guided to the second line oil passage 82 is flowed to the drain boat 134c communicating with the drain is repeated, and the second line oil pressure P2□ is generated. Since the second line oil passage 82 is a relatively closed system, the second pressure regulating valve 102 reduces the second line oil pressure by reducing the first line oil pressure Pf, which is a relatively high oil pressure as described above. Pf is generated as shown in FIG.

Pl, =<to4', Pth+W-8+ ・Pe)/
(8z Ax)゛ ...(1) Note that between the first land 118 and the second land 120 of the spool valve 110, pressure reducing oil pressure is supplied through a second line oil pressure reduction control well 380, which will be described later. Signal pressure P as a signal
,. +4 is introduced into the chamber 136, and the spool valve 110 receives the signal pressure P, in relation to the vehicle speed. , 4
When the pressure is applied in the valve closing direction, that is, in the direction in which the pressure regulation value decreases, the second line oil pressure PI! ,
□ is designed to be depressurized. 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, an eleventh 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 has a bow 150a communicating with the first line oil passage 80 and a drain bow 1-150b or 150.
c, and its first land 152
The first line hydraulic pH as a feedback pressure on the end face of
A chamber 153 is provided for acting through a throttle 151, and the spool valve element 140 is biased in the valve opening direction by this first line oil pressure Pt2+. A chamber 156 for introducing the throttle pressure PLk is provided between the first land 154 and the second land 155 of the first plunger 146 provided coaxially with the spool valve element 140. and second plunger 1
48 is the hydraulic pressure pin in the primary hydraulic cylinder 54.
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.
A chamber 158 is provided for introducing line hydraulic pressure PA.

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 1, 40 is reduced to A6, the first plunger. If the cross-sectional area of the first land 154 of 146 is A, the cross-sectional area of the second land 155 and the second plunge middle 148 is A1, and the biasing force of the return spring 144 is W, then the spool valve 1
40 is balanced at a position where the following equation (2) holds true, and the first line oil pressure P2□ is regulated.

Pl, = [(7, or Pj! z) ・A7+Pth(86-
A? ) 10 W) / As... (2) In the first pressure regulating valve 100, the hydraulic pressure Pin in the negative side hydraulic cylinder 54 is the second line hydraulic pressure Pf.

(In a steady state, Plz = hydraulic pressure P in the secondary side hydraulic cylinder 56, uL), the first plunger 14
6 and the second plunger 148 are spaced apart, and the hydraulic pressure P in the next hydraulic cylinder 54 is maintained. The thrust force acts on the spool valve element 140 in the valve closing direction, but if the hydraulic pressure pin in the downstream hydraulic cylinder 54 is lower than the second line hydraulic pressure P2□, the eleventh plunger 14.6 and the second plunger 1
48, the second plunger 148
A thrust force due to the second line oil pressure Pffiz acting on the end face of the spool valve element 140 acts in the valve closing direction of the spool valve element 140. That is, the second plunger 148, which receives the hydraulic pressure Pi in the next-side hydraulic cylinder 54 and the second line hydraulic pressure P2□, applies an acting force based on the higher of these hydraulic pressures in the direction of closing the spool valve element 140. Let it work. Note that the first land 152 and the second land 159 of the spool valve 140
A chamber 160 to which a second line oil pressure Pffiz is supplied from a first line oil pressure reduction control valve 440 (described later) via an oil passage 161 is provided between the two. The second line oil pressure P2□ acting in this chamber 160 is equal to the first line oil pressure P2□.
ffi, and N.

When the first line oil pressure reduction control valve 440 operates in the P range and the second line oil pressure Pβ is supplied to the chamber 160, the first line oil pressure Pet is lowered. The first line oil pressure characteristics in this case will be detailed later.

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 is connected to a cam 18 that is rotated together with the throttle valve (not shown).
4 and the cam surface of this cam 184, and this cam 18
4, the thrust from the plunger 186 applied via the spring 18 and the first line oil pressure Pj2. By being positioned at a position where the thrust caused by
Reduce the line oil pressure PR1 and obtain the actual throttle valve opening θ.
The spool valve 190 generates a throttle pressure P corresponding to the throttle pressure P. Figure 5 shows the throttle pressure P
and the throttle valve opening θ.
The oil is supplied through the oil passage 84 to the 17'Ji pressure valve 100, the second pressure regulating valve 102, and the third pressure regulating valve 220, respectively.

The speed ratio detection valve 182 also includes a detection rod 192 that is in sliding contact with the input side movable rotating body 50 of the CVT 14 and is moved in the axial direction by an amount of displacement equal to the amount of displacement in the axial direction. A spring 194 correspondingly transmits a biasing force, and while receiving the biasing force from this spring 194, receiving the second line hydraulic pressure P12 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 VT 14 (■ groove width is reduced), the detection rod 192 is pushed in. Therefore, the oil is supplied from the second line oil passage 82 through the orifice 196 and the spool valve 198
As a result, the flow rate of the hydraulic oil discharged to the drain is reduced, so that the hydraulic pressure downstream of the orifice 196 is increased. This working oil pressure is the speed specific pressure Pe, and as shown in FIG. 6, it increases as the speed ratio e increases. Then, the velocity specific pressure Pe generated in this way
are supplied to the second pressure regulating valve 102 and the third pressure regulating valve 220 through the oil passage 86, respectively.

Here, the speed ratio detection valve 182 has an orifice 196
The second line oil pressure PI! is supplied from the second line oil passage 86 through the second line oil pressure PI! Since the speed specific pressure Pe is generated by changing the release amount of the hydraulic fluid in , 2, the speed specific pressure Pe is limited to a value equal to or higher than the second line oil pressure Pf2. 1) the second operating according to Eq.
In the #A pressure valve 102, as the speed specific pressure Pe increases, the second line oil pressure P1. Decrease z. Therefore, the speed specific pressure P
When e increases to a predetermined value and becomes equal to the second line oil pressure P2□, both are saturated and become constant thereafter.

FIG. 7 shows the output characteristics of the second line oil pressure P2, which is regulated in the second pressure regulating valve 102 in relation to the above-mentioned speed specific pressure Pe. That is, the transmission belt 44 shown in FIG. 8 required for the low-pressure side line oil pressure in relation to the speed ratio e.
Characteristics that approximate the ideal curve for setting the tension to the optimum value can be obtained only by the hydraulic circuit, and when the second line hydraulic pressure PA is generated using an electromagnetic pressure control servo valve controlled by a microcomputer. This has the advantage that the hydraulic circuit is significantly cheaper than the previous one.

The third pressure regulating valve 220 generates an optimum third line oil pressure P13 for operating the reverse brake 70 and the forward clutch 72 of the forward/reverse switching device 16. That is, the third pressure regulating valve 220 is connected to the first line oil passage 8
A spool valve 222 that opens and closes a connection between 0 and the third line oil passage 88, a spring seat 1-224, a return spring 226, and a plunger 228 are provided. 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 Pf3 is introduced as a feedback pressure through the throttle 234''. It is biased in the valve closing direction by line oil pressure Pff.Furthermore, on the first land 230 side of the spool valve element 222, a throttle 238 is provided.
A chamber 240 is provided through which the speed specific pressure Pe is guided, and the spool valve element 222 is urged in the valve closing direction by the speed specific pressure Pe. Inside the third pressure regulating valve 220, the biasing force of the return spring 226 in the valve opening direction is applied to the spool valve element 222 through the spring seat 224.
has been granted. Further, a chamber 242 for applying a throttle pressure P is provided on the end face of the plunger 228, and the spool valve element 222 is urged in the valve opening direction by the throttle pressure P. Further, a chamber 248 is provided between the first land 244 of the plunger 228 and the second land 246 having a smaller diameter than the first land 244 for guiding the third line oil pressure I'' 423 only during reverse movement.

Therefore, the third line oil pressure Pf is regulated to an optimal value based on the speed specific pressure Pe and the throttle pressure Ptb using an equation similar to equation (1) above. This optimal value is a value necessary and sufficient to ensure that torque can be transmitted without slipping in the forward clutch 52 or the reverse brake 50. Also, when moving in reverse, the third line hydraulic pressure Pf is supplied to the above chamber within 24 days.
fi.

is guided, the force that urges the spool valve element 222 in the valve opening direction is increased, and the third line oil pressure Pl is increased. 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 hydraulic pressure Pis 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 Pls is not output, but L (low), S (second)
, when the D (drive) range is being operated, the third
The line oil pressure Pf is exclusively supplied from the output boat 258 to the forward clutch 72 and the chamber 45 of the first line oil pressure reduction control well 440.
At the same time, the oil is supplied to the chamber 432 of the reverse inhibit valve 420, and the oil is drained from the reverse brake 70.
When the operation is in the reverse (reverse) range, the third line oil pressure Pf is transferred from the output boat 256 to the third pressure regulating valve 220,
Lockup control valve 320, chamber 452 of first line oil pressure drop control valve 440, and reverse inhibit valve 42
0 to the boat 422a, the oil is supplied to the reverse brake 70 through the reverse inhibit valve 420, and at the same time oil is drained from the forward clutch 72. When the oil is operated in the P (parking) range, the forward clutch 72 The oil is also drained from the reverse brake 70.

Incidentally, the accumulators 342 and 340 are for gradually increasing the hydraulic pressure to smoothly advance frictional engagement, and are connected to the forward clutch 72 and the reverse brake 70, respectively.

Further, the shift timing valve 210 is connected to the forward clutch 7.
The transient inflow flow rate is adjusted by closing the throttle 212 in accordance with the increase in the oil pressure in the hydraulic cylinder No. 2.

The first line oil pressure pH regulated by the first pressure regulating valve 100 and the second line oil pressure P2□ regulated by the 211Il pressure valve 102 are transferred to the speed change control valve device 260 in order to adjust the speed ratio e of the CVT 14. is supplied to one and the other of the primary hydraulic cylinder 54 and the secondary hydraulic cylinder 56. The speed change control valve device 260 is composed of a speed change direction switching valve 262 and a flow rate control valve 264. Note that the fourth line oil pressure PI! for driving the speed change direction switching valve 262 and the flow rate control valve 264! ,
is the first line oil pressure Pffi by the fourth UN pressure valve 170,
, and is guided by 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 the flow control valve 264 with four first connection paths 270, a second connection path 272 having a first throttle 271,
Boats 278a, 278c, and 278e communicate with the third connection path 274 and the fourth connection path 276, respectively.
, 278 g, and drain boat 2 connected to the drain.
78b and the first line hydraulic pressure PA are supplied to the boat 2
78d and the second line hydraulic pressure Pf are supplied to the boat 2
78f, and a spool valve slidably disposed between a first position that is one end of the travel stroke (upper end in FIG. 9) and a second position that is the other end of the travel stroke (lower end in FIG. 9). 280, and a spring 282 that urges the spool valve element 280 toward the second position.

The spool valve 280 has four lands 279a, 279b, 279c, 27 for opening and closing between each port.
9d is provided. 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, spool bento 280
When the first electromagnetic valve 266 is in the OFF state, that is, in the closed state, the fourth line hydraulic pressure P14 regulated by the fourth pressure regulating valve 170 is applied to the end face on the lower end side. The downstream side of 284 is exhausted and the 4th line oil pressure P! 4 becomes inoperative. Therefore, during the period when the first solenoid valve 266 is in the on state, the spool valve element 280 is located at the second position and the boat 278
a and boat 278b, boat 278d and boat) 2
78e and boat 27 are opened.
Between 8d and 278c and boats 278f and 278g
However, during the period when the first electromagnetic valve 266 is in the OFF state, the spool valve element 280 is positioned at the first position, resulting in a switching state opposite to that described above.

The flow rate control valve 264 is a spool valve controlled by a second electromagnetic valve 268, and is a spool valve that is controlled by a second electromagnetic valve 268, and is
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;
88 toward the second position. The spool valve 288 has four lands 287a, 287b for opening and closing between each boat.
287c.

287d is provided. Similar to the speed change direction switching valve 262, no hydraulic pressure is applied to the end surface of the spool valve element 288 on the spring 290 side because it is open to the atmosphere. However, when the second electromagnetic valve 268 is in the off state, that is, in the closed state, the fourth line hydraulic pressure Pj2 regulated by the fourth pressure regulating valve 170 is disposed on the end surface of the lower end side of the spool valve element 288.
．． is applied, but in the on state, that is, the open state, the downstream side of the throttle 292 is exhausted and the fourth line oil pressure P
(La is in a state where it does not act. Therefore, during the period when the second solenoid valve 26 is in the on state (duty ratio is 100%), the spool valve 288 is located at the second position and the bow) 286c Between boat 286b, boat 286
f and 286e, and between boats 286a and 286b and between boats 286d and 2.
86e is closed, but during the period when the second solenoid valve 26 is in the off state (duty ratio is 0%), the spool valve 288 is placed in the first position and the switching state is reversed to the above. . Note that during the period when the second solenoid valve 268 is in the OFF state, the bows 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.

Throttle 296 and check valve 29 are parallel to each other.
8 is the first line oil pressure P! that is supplied 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 during engine braking. 1 is supplied, the hydraulic pressure P in the secondary hydraulic cylinder 56. ut
This is to prevent a large amount of (-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 passes through the boat 278d, the boat 278e, the third connection passage 274, the boat 286d, the boat 286e, and the secondary oil passage 302 to the secondary side. While flowing into the hydraulic cylinder 56, the hydraulic oil in the downstream hydraulic cylinder 54 is discharged to the drain through the downstream oil path 3001 port 286b, the boat 286a, the first connection path 270, the boat 1-278a, and the boat 278b. be done. From this, the speed ratio e of the CT 14 is changed in the direction of deceleration.

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 passage 80 is connected to the boat 278d, the boat 278c, and the second connection passage 27.
2.Boat 286C, Bo! -286b, -Next side oil passage 3
00 to the primary hydraulic cylinder 54, the hydraulic oil in the secondary hydraulic cylinder 56 flows through the secondary oil passage 302, the boat 286e, the boat 286f, the fourth connection passage 276, the boat 278g, the boat It is discharged to the second line oil passage 82 through 278f. From this, CV
The speed ratio e of T14 is changed in the direction of speed increase. In addition,
- A second throttle 2
73 are provided.

FIG. 10 shows the first solenoid valve 266 and the second solenoid valve 2.
68 driving state, CVT 14 shifting direction and speed ratio e
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 into the throttle hole 2 of the spool valve 288.
94 to the primary side hydraulic cylinder 54, and the hydraulic oil in the secondary side hydraulic cylinder 56 is supplied to the primary side 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 secondary 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 at t is suitably suppressed. The spike-like upper peak of the hydraulic pressure P out in the secondary hydraulic cylinder is released by the throttle 296, and P o
This is because the lower peak of ut 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. 0.2kg/cm
``It opens with a certain degree of pressure difference.

Here, the first line oil pressure P in the CVT 14! 1, when running with positive drive (when driving torque T is positive), as shown in Figure 11, and when running with engine braking (when driving torque T is negative), as shown in Figure 12. A suitable oil pressure value 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 areas of 4 and the secondary hydraulic cylinder 56 are equal,
7> Oil pressure P in the secondary hydraulic cylinder 56 during normal drive running in FIG. 11; u
t, P during engine braking driving as shown in Fig. 12. uL
>P in, and in both cases, the hydraulic pressure in the driving side hydraulic cylinder>the hydraulic pressure in the driven side hydraulic cylinder. Above P8 during forward drive running. ．． generates the thrust of the hydraulic cylinder on the drive side, so in order to generate the thrust to obtain the target speed ratio in the hydraulic cylinder and to reduce power loss, the first line hydraulic pressure is It is desirable to adjust P2° to a value obtained by adding a necessary and sufficient margin oil pressure α to the above pin. However, it is impossible to adjust the first line oil pressure Pj2° shown in FIGS. 11 and 12 based on the oil pressure in one of the hydraulic cylinders. Therefore, in this embodiment, the first pressure regulating valve 100 is provided with a second plunger 148, and P3. , and the second
A biasing force based on whichever higher oil pressure among the line oil pressures P12 is transmitted to the spool valve element 140 of the first pressure regulating valve 100. As a result, a curve indicating Pi and P as shown in FIG. 13, for example. During no-load running when the curve indicating ut intersects, the first line oil pressure p
z is controlled to a value obtained by adding a margin value α to the higher oil pressure value of Pl and second line oil pressure P12. This results in
The first line oil pressure P21 is controlled to a necessary and sufficient value,
Power loss is kept as small as possible. Incidentally, the first line oil pressure Pj shown by the broken line in FIG. 13! , ' are the results when 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). As such, the first line oil pressure Pff is increased in relation to the throttle pressure Pff. Said first pressure regulating valve 10
The pressure receiving area of each part of the spring 144 and the biasing force of the spring 144 are set in this manner. At this time, the first line oil pressure Pff, which is regulated by the first pressure regulating valve 100, is P, 7, or P, as shown in FIG. It increases with ut and throttle pressure P, but is saturated at the maximum value corresponding to throttle pressure Pth. As a result, with the speed ratio e reaching its maximum value and the decrease in groove width of the primary variable pulley 40 being mechanically prevented, the hydraulic pressure Pi in the secondary hydraulic cylinder 54...
Even if P11 increases, the first line oil pressure P11, which is always controlled to be higher than it by a margin value α, is prevented from increasing excessively.

In the first pressure regulating valve 100, the hydraulic oil flowing out from the boat 150b is transferred to the lock-up clutch pressure oil passage 9.
2, the lock-up clutch hydraulic pressure PcL is guided to a pressure suitable for operating the lock-up clutch 36 of the fluid coupling 12 by the lock-up clutch pressure regulating valve 310.
The pressure is regulated accordingly. That is, the lock-up clutch pressure regulating valve 310 receives the lock-up clutch hydraulic pressure Pcl as feedback pressure and urges the spool valve element 312 in the valve opening direction, and the spool valve element 312 urges the spool valve element 312 in the valve closing direction. A spring 314, a chamber 316 to which clutch oil pressure Pet is supplied through a lock-up quick release valve 400 (described later) upon sudden release, and the chamber 316.
The plunger 3]7 urges the spool valve element 312 in the valve closing direction in response to the hydraulic pressure of the anti-boole valve element 31.
2 is the thrust based on the above feedback pressure and spring 3
A constant lock-up clutch hydraulic pressure Pcl is generated by operating the hydraulic oil in the lock-up clutch pressure oil passage 92 so as to be in balance with the thrust of the lock-up clutch pressure oil passage 92 . Furthermore, when the clutch oil pressure P cl is supplied to the chamber 316 at the time of sudden release, the clutch oil pressure PET is increased in order to release the lock-up clutch 36 more quickly. The hydraulic oil discharged from the lock-up clutch pressure regulating valve 310 is sent out through the throttle 318 and the lubricating oil passage 94 to lubricate each part of the transmission, and is also returned to the suction oil passage 78 of the oil pump 74.

The lock-up clutch oil pressure Pet regulated as described above is applied to the fluid coupling 1 by the lock-up control valve 320.
The lock-up clutch 36 is selectively supplied to the engaging side oil passage 322 and the releasing side oil passage 324 of the lock-up clutch 36 to be in the engaged state or the 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 3.
24, and a spring 328 that biases the spool valve 326 toward the release side. An oil passage 257 is provided on the upper end surface side (spring 328 side) of the spool valve 326 from the output boat 256 of the manual valve 250 only when the R range is selected.
In other ranges, a draining chamber 334 is provided.
8 side), there is a chamber 3 into which the signal pressure P*oL2 is introduced when the normal oven type third solenoid valve 330 is in the on state.
32 are arranged. The third solenoid valve 330 is in the on state (
When in the closed state), the signal pressure P on the downstream side of the throttle 331 is equal to the clutch oil pressure PcL. 4. However, when the third solenoid valve 330 is in the OFF state (open state), the signal pressure P, which is downstream of the throttle 331, is drained. 5. is now being resolved. The throttle 331 and the solenoid valve 330 have a signal pressure P. 4. It constitutes a generating means for signal pressure P,. 1. In addition to the lock-up control valve 320, these are supplied to a second line oil pressure drop control valve 380, a lock-up quick release valve 400, and a reverse inhibit valve 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 P3°4. is introduced, but since the chamber 334 is at atmospheric pressure, the spool valve element 326 is positioned toward the spring 328 side, so that the lock-up clutch pressure oil passage 9
2 is supplied to the maintenance side oil passage 322, and the lock-up clutch 36 is stopped.
When the solenoid valve 330 is in the OFF state, the chamber 332 is at atmospheric pressure, so the spool valve element 326 is moved by the spring 3.
28, 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 36
is considered to be in a free state.

Furthermore, when the shift position is changed to the R range, the third line oil pressure PR3 is supplied to the chamber 334, so that the signal pressure P. 2. 3rd line oil pressure Pfs and spring 32 than the urging force on the spool valve 326 based on
8 is increased, and the spool valve element 326 is preferentially positioned on the lower side of FIG.
is considered to be in a free state.

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 returning from the lock-up clutch 36 via the retaining side oil passage 322 when it is not engaged, are as follows: 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 D34, as shown in FIG. That is, the throttle 344 and the fourth solenoid valve 346 have a signal pressure P. , 4 functions as a signal pressure generating means. In this way, the signal pressure P is regulated by 4 based on the drive duty ratio of the fourth solenoid valve 346.

, 4 is a solenoid pressure switching valve 350 via an oil passage 348.
be led to. This solenoid pressure switching valve 350 is the 16th
As shown in detail in the figure, the drain boat 352a, the oil passage 3
54, a boat 352c that communicates with the oil passage 348, and a boat 352d that communicates with the oil passage 356.
, and the drain boat 352e are arranged to be slidable between 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). The spool valve element 358 includes a spool valve element 358 and a spring 360 that urges the spool valve element 358 toward the first position.

The third line hydraulic pressure Pis is always guided to the chamber 362 on one end (upper end) side of the spool valve 358, while the chamber 3 on the other end (spring 360 side) of the spool valve 358
The hydraulic pressure within the forward clutch 72 is led to 64 .

Therefore, when the shift position is in the P, R, or N range, the hydraulic cylinder of the forward clutch 72 is drained by the manual valve 250, so that the chamber 36 is drained by the manual valve 250.
4 is also in a state where the pressure is exhausted. Therefore, the spool valve 358 is connected to the third line hydraulic pressure PR1 led to the chamber 362.
between the boat 352c and the boat 352b, and between the boat 352d and the boat) 352.
Since the signal pressures P1 and P4 are communicated with each other, the signal pressures P1 and P4 pass through the oil passage 354 and reach the chamber 177 of the 411th pressure valve 170.
At the same time, the hydraulic pressure in the oil passage 356 is drained. However, when shifting from the N 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, and the third Line hydraulic PI! , rises to . From this, before the forward clutch 72 is engaged (before the pressure in the chamber 364 increases to the third line oil pressure Fix), the signal pressure P in the oil passage 348. 2. is applied to the fourth pressure regulating valve 170 through the solenoid pressure switching valve 350, but the forward clutch 7
2 is in the engaged state (the pressure inside the chamber 364 has increased to the third line oil pressure PR), the spool valve 358
The boat 352b and the boat 352a communicate with each other, and the boat 352C and the boat 352d communicate with each other.
The inside of the oil passage 354 is drained, and the signal pressure inside the oil passage 348 is increased to P8°1. is led to the second line oil pressure reduction control well 380 and the lock-up quick release valve 400 via the solenoid pressure switching valve 350 and the oil passage 356.

Here, the back pressure control of the accumulators 340 and 342 is as follows:
Shift shock during N→D shift and N-R shift (
This is done in order to reduce the engagement shock.When the clutch is engaged, the increase in the oil pressure in the hydraulic cylinder is suppressed for a short period of time to reduce the shock.

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 accumulators 342 and 340.

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

A chamber 176 is provided between the first land 173 and the second land 174 of the spool valve element 171 to introduce the fourth line hydraulic pressure P14 through the throttle hole 175 in order to act as feedback pressure. Benko 17
A signal pressure P is applied to the end surface of the first spring 172 in the valve opening direction.

A chamber 177 for introducing spool valve 171 is provided.
The end face on the non-spring 172 side is open to the atmosphere. In the fourth pressure regulating valve 170 configured in this way, the spool valve element 171 receives a biasing force in the valve closing direction based on the feedback pressure corresponding to the fourth line oil pressure F'1.4, and a biasing force in the valve opening direction due to the spring 172. Biasing force and signal pressure P,.

, 4 in the valve opening direction are balanced, the fourth line oil pressure Pffi, becomes the signal pressure P
The pressure is regulated to correspond to 8°14. That is, N-D
A signal pressure P is passed through the two solenoid pressure switching valve 350 during a shift and an N→R shift. , 4 is the fourth pressure regulating valve 17
0, as shown in FIG.
Line oil pressure Pf4 is the duty ratio D of the fourth solenoid valve 346
Since it is controlled to the value corresponding to s4, the shift shock (
The fourth solenoid valve 346 is duty driven to generate a back pressure suitable for reducing the locking shock. Further, the oil pressure in the forward clutch 72 is the third line oil pressure Pf.
The signal pressure P, which is being supplied to the fourth pressure regulating valve 170 by rising to fi. t4 is the solenoid pressure switching valve 35
When the inside of chamber 177 is opened to the atmosphere after being shut off by 0,
The fourth line oil pressure Pffi is controlled to a relatively low constant pressure of about 4 kg/cm'' corresponding to the urging force of the spring 172 in the valve opening direction.The fourth line oil pressure is regulated to this constant pressure. Pla is exclusively the gear change direction switching valve 262
It is also used as the driving oil pressure for the flow rate control valve 264.

Incidentally, the accumulator 372 provided in the oil passage 354 is for absorbing the pulsation of the signal pressure P9° which is related to the duty drive frequency of the fourth solenoid valve 346.

Returning to FIG. 1, the second line oil pressure reduction control valve 380 is
The transmission belt 44 is driven by the centrifugal hydraulic pressure in the driven hydraulic cylinder.
This is provided to prevent overload from being applied to the secondary hydraulic cylinder 56, which is mainly the driven side, during high-speed running, that is, when the output shaft 38 of the CVT 14 rotates at high speed. Decrease line oil pressure P2□. The second line oil pressure reduction control valve 380
56, and a boat 382 that communicates with the hydraulic chamber 136 of the second pressure regulating valve 102 via the oil passage 384.
b, and the drain boat 382C, the first position which is the upper end of the moving stroke, and the second position which is the lower end of the moving stroke.
The spool valve element 386 includes a spool valve element 386 that is slidably disposed between the two positions and a spring 388 that urges the spool valve element 386 toward the second position. Therefore, when the third solenoid valve 330 is in the off state (open state), the chamber 390
The pressure within the hydraulic chamber 136 of the second pressure regulating valve 102 is drained, and the spool valve element 386 is placed in the second position, and the boats 382b and 3820 communicate with each other.
Line oil pressure PR,t is controlled according to equation (1). However, when the third solenoid valve 330 is in the on state (closed state), the signal pressure P1° is applied to the chamber 390 on the lower end side of the spool valve element 386.
3 (clutch pressure Pe1.) is introduced, the spool valve 386 is positioned at the first position, and the boats 382a and 3
82b are communicated with each other. At this time, the fourth solenoid valve 34
6 is also in the on state (closed state) and the forward clutch 72
is in the engaged state, the oil passage 356, the boats 382a, 3
The Kura-Sochi hydraulic pressure Pct is supplied into the hydraulic chamber 136 of the second pressure regulating valve 102 through the oil passage 384 and the hydraulic pressure 82b. Since this clutch oil pressure Pet urges the spool valve element 110 of the 211th pressure valve 102 in the valve closing direction, the second line oil pressure Ph is regulated according to the following equation (3), and as shown in the dashed line in FIG. , is lower than the normal second line oil pressure shown by the solid line.The third solenoid valve 330 and the fourth
When the solenoid valve 346 is turned on when the vehicle speed exceeds a judgment reference value ML3 (described later), the influence of the centrifugal hydraulic pressure in the secondary hydraulic cylinder 56 is eliminated, and the transmission belt 4
4 durability is increased. As described above, in this embodiment, the signal pressure P is supplied to the chamber 136 of the second iFl pressure valve 102 via the second line oil pressure reduction control well 380 by the operation of the third solenoid valve 330 and the fourth solenoid valve 346. L4 is
Second line hydraulic pressure Pl supplied to the driven side hydraulic cylinder
This corresponds to a pressure reducing hydraulic signal for energizing the spool valve element 110 in the direction of decreasing the pressure adjustment value of t. Note that even if the third solenoid valve 330 is in the on state, if the fourth solenoid valve 346 is in the off state, the second line oil pressure P! 2 is the above (1)
B is controlled normally according to the formula.

pp, -(A4・P+W-A, -P.

-(A2-A1)'Pcl) /(^3-A2)-
--(3) Next, the lock-up quick release valve 400 provided to improve the release response of the lock-up clutch 36 is connected to a boat 402 that communicates with the clutch pressure oil passage 92.
a, a boat 402b that communicates with the hydraulic chamber 316 on the end face of the plunger 317 of the lock-up clutch pressure regulating valve 310 via an oil passage 404; The boat 402d and the first
The spool valve element 406 includes a spool valve element 406 that is slidably disposed between this position and a second position, which is the lower end, and a spring 408 that biases the spool valve element 406 toward the second position. The chamber 410 on the lower end side of the spool valve 406 is
When the forward clutch 54 is engaged, the fourth solenoid valve 3
Clutch pressure PcL is introduced when 46 is in the on state, and is exhausted when it is in the off state. Also, the chamber 41 on the upper end side (spring 408 side) of the spool valve 406
2 is the signal pressure P when the third solenoid valve 330 is in the on state. 1. (clutch pressure Pct) is introduced, and is exhausted when the clutch is in the off state. Lock-up quick release valve 40
0 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 element 406 is controlled by the third solenoid valve 330 and the fourth solenoid valve 346. 1 position, clutch pressure P
ct is boat 402a, boat 402b, oil passage 404
The operating pressure PCI is guided to the hydraulic chamber 316 of the lock-up clutch pressure regulating valve 310 to raise the clutch pressure PCI, and at the same time is discharged from the engagement-side oil chamber 33 of the fluid coupling 12 through the engagement-side oil passage 322. As oil drains from the upstream side of cooler 339 via boats 402d and 402c, lockup clutch 36 is rapidly disengaged. Note that when the third solenoid valve 330 and the fourth solenoid valve 346 are in other states, the spool valve element 406 is located at the second position. At this time, lock-up quick release valve 4
00 not only reduces the flow resistance of the hydraulic oil discharged from the engagement side oil chamber 33 of the fluid coupling 12, but also supplies it to the disengagement side oil chamber 35 of the fluid coupling 12 by the lock-up clutch pressure regulating valve 310. Since the clutch pressure PCL is increased, high release response of the lock-up clutch 36 can be obtained.

The reverse inhibit valve 420 provided to prohibit reverse during forward running is a boat 422a to which the third line hydraulic pressure Pls is supplied from the output boat 256 when the manual valve 250 is in the R range;
A boat 422b communicating with the hydraulic cylinder of the reverse brake 70 via an oil passage 423, and a drain port 42
2c, a spool valve element 424 slidably disposed between a first position, which is the upper end of the movement stroke, and a second position, which is the lower end; A spring 426 is provided. A signal pressure P is supplied to the chamber 428 on the upper end side of the spool valve element 424 via the oil passage 430 when the third solenoid valve 330 is in the on state. (clutch pressure Pct) is introduced, and is exhausted when it is in the off state. When the manual valve 250 is in the S or L range, the third line hydraulic pressure Pf is introduced into the chamber 432 on the other end side (spring 426 side) of the spool valve element 424 from its output boat 258. In the reverse inhibit valve 420 configured in this way, the third line oil pressure P2 in the chamber 432 is exhausted and a signal pressure P is applied to the chamber 428. 1. When the spool valve element 424 is positioned at the second position (lower end) by introducing the clutch pressure Pc1, the communication between the boat 422a and the boat 422b is cut off, thereby supplying hydraulic oil to the reverse brake 70. is blocked and boat 4
By communicating between 22C and bow 1-422b, the hydraulic oil in the hydraulic cylinder of the reverse brake 70 is drained, so switching of the forward/reverse switching device 16 to reverse is prohibited. Therefore, if the shift lever 252 is erroneously operated from the D range, past the N range, and into the R range while the vehicle is moving forward, the third solenoid valve 330 is turned on by the electronic control device 460, which will be described later. The forward switching device 16 is placed in a neutral state.

The first line oil pressure reduction control valve 440 is provided to suppress belt noise by reducing the first line oil pressure PR8 by a predetermined pressure when the shift position is in the N or P range.
The drain boat 442a, the chamber 160 between the first land 152 and the second land 154 of the 111th pressure valve 100, and the oil passage 1
61, and a boat 442c communicating with the second line oil passage 82,
44, a spool valve 446 that opens and closes between the second line oil passage 82 and the chamber 160 of the first pressure regulating valve 100, and a spring 448 that biases the spool valve 446 in the opening direction. Chamber 450 on the lower end surface of the plunger 444
is communicated with the output boat 258 of the manual valve 250 that outputs the third line hydraulic pressure PR1 when in the forward range, and the chamber 452 between the plunger 444 and the spool valve 446 outputs the third line hydraulic pressure PR1 when in the R range. Line oil pressure P
Output boat 2 of manual valve 250 that outputs lz
It is communicated with 56. Therefore, D, S, LS
In the R range, the spool valve 446 is positioned at the upper end, and the inside of the chamber 160 of the first pressure regulating valve 100 is connected to the drain port 442.
atmospheric pressure through a, and the first line oil pressure Pjl! , is regulated to a normal value according to equation (2) above. but,
In the N and P ranges, the spool valve 446 is positioned at the lower end, and the second line oil pressure Pn is in the chamber 160 of the first pressure regulating valve 100.

is supplied. Therefore, the spool valve element 140 of the 111th pressure valve 100 is urged in the valve opening direction based on the second line oil pressure P2□ acting in the chamber 160, so that the first line oil pressure Pj2. is lowered. As a result, the clamping force on the transmission belt 44 is made as low as possible within a range that does not cause slippage, and in addition to reducing the noise level of the belt, the durability of the transmission belt 44 is increased.

In FIG. 2, an electronic control device 460 functions as the control means of the present embodiment, and controls the first solenoid valve 266, the second solenoid valve 268, and the third solenoid valve in the hydraulic control circuit of FIG. By driving the valve 330 and 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 driving 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 T1.4. A human power shaft rotation sensor 464 and an output shaft rotation sensor 46 detect each other.
6. Throttle valve opening sensor 468 for detecting the opening of the throttle valve provided in the intake pipe of the engine 10; operation position sensor 470 for detecting the operation position of the shift lever 252; and for detecting the operation of the brake pedal. A signal representing the vehicle speed ■, a signal representing the input shaft rotational speed N i n , and an output shaft rotational speed N o
A signal representing uL, a signal representing the throttle valve opening degree θ, a signal representing the operation position P2 of the shift lever 252, and a signal representing the brake operation are supplied, respectively. The CPU in the electronic control unit 460 uses the temporary storage function of the RAM and processes the human power signal according to a program stored in the ROM in advance, and processes the first electromagnetic valve 266, the second electromagnetic valve 268,
A signal for driving the third solenoid valve 330 and 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 r n of the shaft 30, and the rotational speed N of the output shaft 38.

..., the speed ratio e of the CVTi 4, the vehicle speed V, 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, for example, according to the flowchart shown in FIG. 19. Step S
In 1, input signals etc. from each sensor are read, and based on the read signals, vehicle speed ■,
The rotational speed N in of the input shaft 30 and the rotational speed N of the output shaft 38. ut, throttle opening θ, and shift operation position P are calculated.

In step S2, a predetermined relationship [Ni,
, ``=f(θ, V, P,)), the target rotational speed N in '' of the input shaft 30 is determined based on the shift operation position P8, the throttle valve opening θ, and the vehicle speed ■. For example, in order to generate the required output represented by the throttle valve opening θ on the minimum fuel consumption rate curve of the engine 10, a plurality of sets of this relationship are determined in advance for each S and L range. It is stored in advance in the ROM in the form of If the shift operation position is in the S or L range, this is a condition where sporty driving or enhanced engine braking action is required.
In the relationships selected in these S or L ranges,
The target rotational speed N ia ' is set higher so that the vehicle is on the deceleration side even more than when traveling in the D range. Note that the shift operation position for driving is not limited to the three positions in the DXSSL range, but can be arbitrarily set as necessary.

In the following step S3, the control deviation ΔNi between the actual rotational speed N l n of the input shaft 30 of the CVTI 4 and the target rotational speed N i n''', (=Nifi'-Nifi)
is determined. Then, in step S4, one of the plurality of speed change modes shown in FIG. 10 is selected based on the magnitude of the control deviation ΔN in obtained in step S3. This selection method is performed, for example, by selecting one of the shaded areas corresponding to a plurality of types of shift modes shown in FIG. 1O.
A shift mode corresponding to a region including the control deviation ΔN i n 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 is for the purpose of

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, if the initial control deviation ΔN i n is 25Q
When the speed change mode (B) is selected at rpm, and the control deviation ΔN in decreases to 14 or ρm and falls within the overlap between the speed change mode (B) and the speed change mode (C), Shift mode (b) is selected. Further, from a state where the control deviation ΔNi is 5 Orpm and the shift mode (c) is selected, the control deviation ΔN4. ．． is 1.
Increase to 2Orpm and change the speed change mode (b) and the speed change mode (
If the shift mode (c) is included in the overlapped region with 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 (E) has been selected. If the shift mode (b) is selected in step S4, the determination in step S5 is affirmative, so in step S7, the duty ratio Dst of the second solenoid valve 268 is calculated according to the following equation (4). . Furthermore, if the shift mode (e) is selected in step S4, the determination in step S6 is affirmative, so in step S8, the duty ratio D8□ of the second solenoid valve 268 is determined according to the following equation (5). Calculated.

D-z=100%-1・ΔN in...(
4) D, □--, ・ΔN... (5)
However, K1 and K2 are constants.

Here, the reason why two types of equations (4) and (5) are used when determining the duty ratio z of the second electromagnetic valve 268 is that the flow rate characteristics of the flow rate control valve 264 are different. FIG. 20 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. 1 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,
20 and 21, the supply oil pressure is kept constant and two output boats 286b and 286e of the flow control valve 264 are shown.
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 turned on, 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 Dst 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 rate control valve 264 becomes fully open. As shown in FIG. 21, the flow rate increases as the duty ratio Dl increases. First solenoid valve 266
The second electromagnetic valve 268 is driven in step S9, which will be described later, according to the duty ratio determined as described above, or in the on or off state determined in step S4. The duty drive of the second solenoid valve on the 26th is, for example, within a certain period (period) To.
T,・Dig/100 hours is in the on state, T,・
(1-D, z/1oo) is executed periodically such that the time is off. Here, the above formula (4) and (5
) The duty ratio Dot determined by the formula increases the flow rate in proportion to the magnitude of the control deviation ΔNAM, and the flow rate is thereby controlled in the direction in which the control deviation ΔN i n is eliminated. The flow rate control valve 26 is controlled by the duty ratio D3□ determined by S7 or S8.
4 is performed (step 512),
Target rotational speed N, fi* and actual rotational speed N i
Feedback control is executed to match n.

In step S9, each control executed by the third solenoid valve 330 and the fourth solenoid valve 346, namely lock-up clutch engagement and release control, lock-up clutch quick release control, accumulator back pressure control, reverse prohibition control,
A control mode determination routine for determining which control mode of the second line oil pressure reduction control is to be executed is executed. This control mode determination routine is shown in FIG. 22, for example.

Among the steps shown in FIG. 22, steps SS1 to S
S7 is a part related to reverse prohibition control.

In step S81, it is determined whether the vehicle speed ■ is equal to or higher than a constant vehicle speed value CV+ stored in advance in the ROM. This judgment reference value Cvl is determined by the shock generated when the forward/reverse switching device 16 is switched to reverse.
This is preset in order to judge whether the vehicle speed is such that the transmission belt 44 of the VTl 4 does not slip, and is set to a value of about 7 to 10 km/h, for example. In step SSL above, the vehicle speed ■
When it is determined that CV is less than 1, step S
82, the content of the flag XREV is zero (XREV=0
), the shift lever 2 is moved in step SS3.
52 is being operated to the R range.

If it has been operated, the content of the flag XREV is set to 1 (XREV=1) in step SS7. In other words, when driving is started in R range, XREV=
However, when driving is started in a range other than the R range, XREV=O.

When the vehicle speed {circle around (2)} becomes equal to or higher than the predetermined vehicle speed value Cv1, the determination in step SSI is affirmed, and therefore, in step SS4, it is determined whether or not the R range is being operated.

Since there is no need to perform reverse prohibition control when the R range is not operated, it is determined in step SS5 whether or not the N or P range is selected, and if the operation is in the N or P range, the lock-up clutch 36 is activated. The lock-up clutch release control mode (A) is selected. As shown in FIG. 23, in the lock-up clutch release control mode (A), the third solenoid valve 330 and the fourth solenoid valve 346 are both in the OFF state, and the lock-up clutch 36 is in the released state regardless of the vehicle speed. It is said that However, if it is determined in step S85 that the range is other than the N or P range, that is, the forward range, step SS9 is executed. However, if it is determined in step 334 that the vehicle is in the R range, then 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 XR, EV-1, it is a continuous reverse range state, so step SS8 is executed, but if XREV is not 1, reverse prohibition control mode (D) is selected. That is, steps SSI, SS4. SS6 corresponds 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 Cv1, the determination in step SS6 is denied, and therefore the reverse is reversed as described above. Prohibition control mode (D) is selected. As shown in FIG. 23, 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 reverse 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 Cv1 or higher, or if you first operate N range and then operate R range again when vehicle speed ■ exceeds CV1, XREV-1 Therefore, since the determination at 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 it is not the reverse prohibition control and it is not in the N or P range, the above-mentioned step SS8 is executed when in the R range.
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 (6).
The rotational speed difference Nd is calculated, and in the forward ranges such as the D, S, and L ranges, step SS9 is executed to calculate the rotational speed difference Nd according to the following equation (7).

Nd= l Nout 1p-Npcl...
(6) Nd=lNout−Npel −・
・C't) Here, N out is the rotational speed of the output shaft 38 of the CVT 14, Npc is the rotational speed of the carrier 60 of the forward/reverse switching device 16, and ip is the rotational speed of the forward/reverse switching device 1 when traveling in reverse.
It has a gear ratio of 6. The above Npc has a completely one-to-one correspondence with the vehicle speed ■, and is obtained according to the following equation (8). Further, the above ip is obtained from N out and N pc when the reverse brake 70 is fully engaged according to the following equation (9).

N, c=C/V...(8) i o = N
oat/Npc...(9) 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 CM stored in advance in the ROM. This determination reference value CM is a value for determining whether engagement of the forward clutch 72 or the reverse brake 70 has been completed, and a value of about 30 rpa+ is adopted, for example.

In step 3310, if it is determined that the rotational speed difference Nd is not larger than the judgment reference value CM, the integration is completed, and steps 5S12 and subsequent steps are executed; however, if it is determined that it is larger, Step S S 1
．． 1, it is determined whether the elapsed time since the shift from the N or P range to the DS, S, or L range has exceeded a determination reference value CT stored in advance in the ROM.

This determination reference value C1 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 S
In S1.1, if it is determined that the elapsed time exceeds the judgment reference value CT, steps 5S12 and subsequent steps are executed, but if it is judged that the elapsed time does not exceed the judgment reference value C7, the accumulator Back pressure control mode (C)
is selected.

Step 5 SIO or SS 1. If the determination in l 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 selected, the lock-up clutch release control mode (A) is immediately selected. be done. This results in
In the R range state, the third solenoid valve 330 is turned on and reverse prohibition control is performed, thereby preventing the vehicle from 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 3313 whether or not the brake switch 472 is in the on state, and in step 5S14, the vehicle speed is determined as a criterion previously stored in the ROM. It is determined whether it is lower than the value Cv2. This judgment standard value Cv! is a value for determining whether or not the lock-up clutch 36 is released when the brake is being operated, and a value of about 40 km/h is adopted, for example.

In steps 5S13 and 5S14, the brake switch 472 is in the ON state and the vehicle speed ■ is Cv! If it is determined that the lock-up clutch release control mode (A) or the lock-up clutch sudden release control mode (B) is determined to be lower than Step 3322 and subsequent steps are executed. In step 5S22,
It is determined whether the current control mode is control mode (A) or (C) in which the lock-up clutch 36 is maintained in a released state without sudden release.

If the determination is affirmative, the normal lock-up clutch release control mode (A) is selected, but if the determination is negative, it is determined in step 3323 whether the current control mode is the quick release control mode (B). be done. 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 3325, and then the quick release control mode CB) is selected. If it is determined that (B) is the case, 1 is counted in the timer counter XLC in step 5S24, and then in step 5S26 it is determined whether the count content of the timer counter XLC has reached the judgment reference value C8 stored in advance in the ROM. is judged. If the sudden release control mode (B) is not reached yet, the quick release control control mode (B) will be continuously selected, but if it is reached, the control mode (A)
can be switched to In this way, the quick release control mode (B) is maintained for a short period of time corresponding to the judgment reference value C8, so that the engagement side oil chamber 33 is locked up and the quick release valve 400 is drained via the retention oil passage 322. By doing so, the internal pressure of the fluid coupling 12 is reduced and the generation of bubbles within the fluid coupling 12 is eliminated as much as possible. The criterion value C6 is thus set smaller than the value corresponding to the time required to generate bubbles within the fluid coupling 12.

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 changed to a 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 to engage or disengage the lock-up clutch 36. If the judgment in step 5S15 is affirmative, in step 5S18 the input shaft rotational speed Ni, .
It is determined in step 5S19 whether or not the vehicle speed is greater than a predetermined determination reference value ML2, and whether or not the vehicle speed ■ is greater than a determination reference value CV4 stored in advance in the ROM. If either step 5sis or step 5Si9 is negative, the normal mouth/knob/knob clutch release control mode (A) is selected, so that the released state of the lock-up clutch 36 is maintained. However, if the input shaft rotational speed N i n is the predetermined judgment reference value ML
2 (and the vehicle speed ■ is larger than the judgment reference value CV4, steps 5S20 and subsequent steps are executed and the second line oil pressure reduction control mode (E) or reverse prohibition control mode (D ) is selected.The second line oil pressure reduction control mode (E) and the reverse prohibition control mode (D) are the control to engage the lock around-free latch 36 because the third solenoid valve 330 is turned on. mode.

On the other hand, if it is determined in step 3315 that the current control mode is not one of (A), (B), and (C), then in step 5S16 the input shaft rotational speed N in is set to a predetermined determination reference value. It is determined whether or not the vehicle speed is greater than M mouth, and at the same time, in step S S 1.7, it is determined whether or not the vehicle speed is greater than a determination reference value Cv3 stored in advance in the ROM. Above step SS
If the judgments in steps 1.6 or 5S17 are negative, the normal lock-up clutch release control mode (A) is selected, but if the judgments in steps S1.6 and 3317 are both affirmative, Step 5S20 and subsequent steps are executed. Therefore, steps 3315 to 5S above
In step 19, when the lock-up clutch 36 is released, the lock-up clutch 36 is engaged when the conditions that N i , > M , , z and ■>Cv4 are satisfied. Further, in a state where the lock-up clutch 36 is engaged, N i
, l<M t t or v<Cv3, the lock-up clutch 36 is released.

Here, the above judgment reference values MLl and ML2 are set in advance as R
It is determined based on the throttle valve opening θl from a function stored in the OM, and the value increases as the throttle valve opening θl increases. Further, if the throttle valve opening degree θ is the same, M L l > M I-t is established in order to prevent fluctuating control. In addition, the above judgment reference values Cl1l and C10 are 20km/
The value is about h, and for those as well, Cl13>Cv4
It is said that

In step 5S20, the throttle valve opening θ and the input shaft rotational speed N 4 n are determined based on the pre-stored relationship.
Based on this, the judgment reference value ML3 (kIIl/h) is determined. FIG. 25 shows an example of the above-mentioned pre-stored relationships in the form of a data map. Note that when the throttle valve opening degree θ and the input shaft rotational speed N L n are intermediate values between the values shown in FIG. 25, the judgment reference value ML3 is calculated by the interpolation method. Then, in step 5S21, the vehicle speed ■ is the judgment reference value Ml! It is determined whether or not it is greater than . The vehicle speed ■ is the judgment reference value M5. If it is determined that the oil pressure is higher than Oil pressure PA is reduced. However, step 5S21
If it is determined that the vehicle speed V is less than or equal to the determination reference value ML3, the reverse prohibition control mode (D) is selected and the second line oil pressure pz.

is controlled to a normal value.

Returning to FIG. 19, when one of the control modes (A), (B), (C), (D), and (E) is determined as described above in step S9, in step S10 It is determined whether the control mode is (C). If it is determined that the control mode is (C), step 31
Step 312 is executed after the duty ratio Ds4 is determined in No. 1, but if it is determined that the control mode is not (C), step S12 is directly executed.

The duty ratio D14 is determined so as to generate back pressure in the accumulators 342 and 340 to ensure smooth engagement when the forward clutch 72 or the reverse brake 70 is engaged. The duty ratio DI4 at the time of a forward shift and a reverse shift is, for example, a function at a forward shift and a reverse shift that is stored in advance in the ROM and uses variables such as the input shaft rotational speed N1fi at the time of the shift and the elapsed time from the shift. are determined sequentially according to each. FIG. 24 shows the duty ratio Ds4 and the output shaft rotation speed N01 when the vehicle is stopped (N-+D shift). Each shows the changes over time. In step S12, the first solenoid valve 266, second solenoid valve 268, third solenoid valve 330, and fourth solenoid valve 346 corresponding to each control mode determined in steps S4 and S9 are turned on or off. A drive signal is output so that the state is obtained.

In the hydraulic control circuit of this embodiment, as described above, the second line hydraulic pressure F'1.
Spool valve 110 and its spool valve 1 for regulating pressure t
A second pressure regulating valve 102 includes a chamber 136 that receives a pressure reducing oil pressure signal (P, .14) for applying a biasing force in the direction of decreasing the second line oil pressure P2 Based on the relationship shown in the figure, the judgment reference value Ml is determined based on the throttle valve opening degree θ, h and the input shaft rotational speed N, , (=N,), and the vehicle speed ■ is the judgment reference value M, 1. determination means (
Step 3320, 5S21. ) and a pressure reducing oil pressure signal generating means for supplying the pressure reducing oil pressure signal to the chamber 136 based on the determination. Therefore, when the vehicle speed ■ exceeds the judgment reference value ML3, the pressure reducing oil pressure signal generating means generates a pressure reducing oil pressure signal, and the second pressure regulating valve 1
Since the second pressure regulating valve 10 is supplied to the chamber 136 of
2 is the second line hydraulic pressure P1.2 supplied into the driven side hydraulic actuator. The pressure is reduced as shown in FIG.

As a result, 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 durability of the transmission belt 44 is increased. Moreover, since a pressure control servo valve with a linear solenoid is not used, the hydraulic control device is inexpensive. Here, in this embodiment, the signal pressures P3° and 4 supplied from the second line oil pressure reduction control well 380 to the chamber 136 of the second pressure regulating valve 102 correspond to the pressure reduction oil pressure signal,
By executing step S20, the throttle valve opening θ and the input shaft rotational speed N1 are determined from the relationship stored in advance.
Based on the judgment standard value M5. is determined, and step S21
By executing 2nd line oil pressure reduction control mode (
The electronic control device 460 that selects the mode E) corresponds to the determination means, and the third solenoid valve 330 and the fourth solenoid valve 346, which are driven when the second line oil pressure reduction control mode (E) is selected, and the The two-line oil pressure reduction control valve 380 and the like correspond to the pressure reduction oil pressure signal generation means.

Moreover, according to the present embodiment, the judgment reference value M4. is determined based on the engine rotational speed N0 of the vehicle and the throttle valve opening θ (required output value) from a predetermined relationship in step S20.

Therefore, the state in which the vehicle speed ■ exceeds the above-mentioned judgment reference value ML3, in other words, the vehicle state is in the second line oil pressure reduction region determined based on the vehicle speed ■, the engine rotation speed N, and the throttle valve opening θth. Since the second line hydraulic pressure P12 is reduced in the state where the transmission belt 44 is
The tension is better controlled. That is, CVT14
The input torque Tj, (=actual output torque T of the engine) is determined by the throttle valve opening θ, as shown in FIG.
Since it depends not only on the engine speed but also on the engine rotational speed N, the reference value for determining the pressure adjustment value from the throttle valve opening θt and the speed ratio e and generating the pressure reduction oil pressure signal is When the hydraulic pressure is constant, the hydraulic pressure in the driven side hydraulic cylinder of a belt type continuously variable transmission is not the optimum value for the transmitted torque, and the pressure regulation value is higher overall. For example, since the judgment reference value ML3 is determined in consideration of the engine rotational speed N and the throttle valve opening θ, the hydraulic pressure P applied to the driven side hydraulic actuator is
j2. The pressure adjustment value and the tension of the transmission belt 44 are appropriately controlled.

The above operation will be explained in more detail below. C
The optimum oil pressure P1 necessary and sufficient to transmit power without causing slippage of the transmission belt 44 in the VT 14 is expressed as shown in the following equation 0ω.

-C3・(e-Nifi)" -=-QO) Here, in the above equation 00), C,, C2, and C1 are constants. Also, the first term on the right side of the 0ω equation is the input torque T in
The pressure value is determined to transmit the input torque T (n) without causing slippage of the transmission belt 44 from the speed ratio e, and the second term on the right side is C
The input torque T to the VT 14 is equal to the output torque T of the engine 10, and the input shaft rotation speed Nin is equal to the engine rotation speed N. The output torque T, ) is expressed by the following formula (11
) or can be determined based on the input shaft rotational speed Ni, (engine rotational speed N, ) and the throttle valve opening θ by the function shown in FIG.

Tin=Te=f(θ,,,N,)=f(θth+
Niゎ)...(11) As mentioned above, the optimal oil pressure P is the function f(θth+e
+N1n) or f(θLh+ N in+ N ou
On the other hand, the second line oil pressure Pj22 is actually controlled based on the throttle valve opening θLhs speed ratio e, as shown in FIG. The above actual 2nd line oil pressure P
If P is calculated as the difference between h and the optimum oil pressure P, the result will be as shown in FIG. 27. In the figure, as the vehicle speed increases, the influence of the centrifugal oil pressure becomes larger and the excess oil pressure Δ
A general tendency for P to become large can be seen.

For this reason, it is sufficient that the reduction control is switched on and off along the line of the margin oil pressure ΔP corresponding to the pressure reduction value to be reduced during the second line oil pressure reduction control, but the centrifugal oil pressure cannot be corrected only by this. That is, in FIG. 28, the normal value of the second line oil pressure Pit shown by the solid line and the decreased value shown by the dashed-dotted line are shown, but the speed ratio detection valve 18
Since the source pressure of 2 is the second line oil pressure P12, the speed specific pressure P8 and the second line oil pressure P2□ are the same in the area below the diagonal broken line, so the surplus pressure ΔP and it are generated. As shown in the relationship with the second line oil pressure decrease amount ΔP' (FIG. 29), in order to correct the margin pressure ΔP, the pressure regulation value by the second pressure regulating valve 102 must be reduced by ΔP'. ΔP" is obtained as follows. If the second line oil pressure Pj2 is not controlled to decrease. When both P and the optimum oil pressure P are in the region below the broken line, the pressure regulation characteristics for the speed ratio shown in FIG. Draw a line with the same slope as the slope (in the region above the broken line, find the distance to the two slope lines at a common speed ratio, ΔP.

can be determined. If the second line oil pressure P2□, which is not subjected to reduction control, is in the area above the broken line and the optimum oil pressure P is in the area below the broken line, then the optimum oil pressure P
8 only, find the intersection of the horizontal line and the broken line, draw a line at the above slope, and draw the second line oil pressure P12 on the upper side.
.DELTA.P' can be determined by drawing slope lines passing through points indicating .DELTA.P' and finding distances from those slope lines at the same speed ratio. FIG. 29 shows this state. Also, if the second line oil pressure P! is not controlled to decrease! , and the optimum oil pressure P are in the region above the dashed line, ΔP' can be determined by simply finding the difference between them.

FIG. 30 shows the actual second line oil pressure reduction amount ΔP° for correcting the margin oil pressure ΔP shown in FIG. 27 by the above calculation. If the second line oil pressure decrease amount Δ
When P' is 8 kgf/cm3, Δ in Fig. 30
The second line oil pressure reduction control mode (E
) (on-on). FIG. 25 shows the throttle valve opening θ in order to switch along the above line.
and the reference value M in relation to the input shaft rotational speed N, .

This is a data map that corresponds to

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

Figures 31, 32, 33, 34, and 3
FIG. 5 shows another example of the hydraulic control circuit of the present invention, which is operated according to the flowchart shown in FIG.

In FIG. 31, in addition to the above-mentioned mechanism, the second line oil pressure reduction control valve 380 includes a plunger 480 that is provided coaxially with the spool valve element 386 and can come into contact with it via a bottle 486. A chamber 482 into which the hydraulic pressure acting on one end (the signal hydraulic pressure P8, 4 in the chamber 136 of the second pressure regulating valve 102) is guided, and the hydraulic pressure acting on the other end of the plunger 480 (the second line hydraulic pressure P8, 4) is introduced. A chamber 484 is further provided, into which a signal hydraulic pressure P1°5.) for switching the control well 380 is introduced. These additional mechanisms are intended to provide a fail-safe function against valve sticking, so that even if the spool valve element 386 of the second line oil pressure drop control valve 380 sticks, the second line oil pressure P2□ This eliminates the possibility that the transmission belt 44 would slip due to an unnecessary drop in the torque.

The third solenoid valve 330 is in the on state and the fourth solenoid valve 34
6 is in the on state, duty state, or off state, when the third solenoid valve 330 is switched to the off state and the fourth solenoid valve 346 is switched to the on state, the second It is possible that the line oil pressure P2□ decreases unnecessarily. However, when the third solenoid valve 330 is switched from the on state to the third solenoid valve 330 off state and the fourth solenoid valve 346 to the on state, the spring 388 is turned off by the stick of the spool valve element 386.
If the plunger 480 does not move in the biasing direction of the spool valve 38, the plunger 480 moves in the biasing direction of the spool valve 38 in accordance with the biasing force based on the pressure reducing hydraulic signal (P, ., 4) supplied to the chamber 482.
6 is forced down.

In the second line oil pressure reduction control of this embodiment, when the reverse prohibition control mode (D) is selected, the third solenoid valve 330 is turned on and the fourth solenoid valve 346 is turned off, and the forward range is changed to R. Establishment of reverse gear is prohibited during range operation. However, when the vehicle speed takes an intermediate value between the second line oil pressure reduction control mode (E) and the reverse prohibition control mode (D), the second second line oil pressure reduction control mode (F) is selected. , when the third solenoid valve 330 is in the on state, the fourth solenoid valve 346 is driven on duty, so that the second line oil pressure P12 is continuously lowered. Then, when the second line oil pressure reduction control mode (E) is selected and both the third solenoid valve 330 and the fourth solenoid valve 346 are turned on, the second line oil pressure P12 is lowered by a predetermined amount.

In FIG. 32, the second line oil pressure reduction control well 380
A switching boat is added, and a second line oil pressure increase control valve 490 is provided to increase the second line oil pressure P12 by a predetermined amount from the standard value. Second
Line oil pressure reduction control valve 380 is connected to boats 492a and 494a, which are connected to oil passage 86 that guides speed specific pressure P,
Boat 492 connected to chamber 130 of second pressure regulating valve 102
b, boat 494b connected to second line hydraulic pressure rise control valve 490, drain boats 492c and 494c
and a signal pressure P, respectively. 13 is supplied and the spool valve element 386 is moved against the biasing force of the spring 388, the chamber 130 of the second pressure regulating valve 102 and the second
The speed specific pressure P0 is supplied to the line oil pressure increase control valve 490, the supply of the signal pressure P1°13 is canceled, and the spool valve 3
86 is moved according to the biasing force of the spring 388, the speed specific pressure P0 that was being supplied to the chamber 130 of the second pressure regulating valve 102 and the second line oil pressure increase control valve 490
is released to the atmosphere.

The second line oil pressure increase control valve 490 has a boat 496a connected to the port 1-494b of the second line oil pressure drop control valve 380, a boat 496a connected to the chamber 136 of the second pressure regulating valve 102, and a drain boat. 496c, a spool valve element 498 that selectively switches the chamber 136 of the second pressure regulating valve 102 between the boat 494b of the second line oil pressure reduction control valve 380 and the atmosphere, and a spring 500 that biases the spool valve element 498. and a signal pressure P,
. , 4 are supplied, and the spool valve 498 is connected to the spring 5.
00, the speed specific pressure P0 passing through the second line oil pressure reduction control well 380 changes to the second pressure regulating valve 1.
The signal pressure P, is supplied to the chamber 136 of 02. 14 is removed and the spool valve element 498 is moved according to the biasing force of the spring 500, the second pressure regulating valve 102
The chamber 136 is open to the atmosphere.

Therefore, as shown in FIG. 36, 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 supplied with the speed specific pressure P, so the second
The line oil pressure P12 has normal characteristics as shown in FIG. However, when the third solenoid valve 330 is in the off state and the fourth solenoid valve 346 is in the on or off state,
As shown in FIG. 36, since chambers 130 and 136 of the second pressure regulating valve 102 are both at atmospheric pressure, the second line oil pressure P
ffi has a flat characteristic. As a result, when the vehicle enters a low speed state where the lock-up clutch 36 is released,
In particular, since the second line oil pressure P2□ is increased on the side where the speed ratio is large, the speed ratio of the CVT 14 can be quickly returned to the maximum deceleration side when the vehicle suddenly stops. Further, 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 transferred to the chambers 130 and 136 of the second pressure regulating valve 102, as shown in FIG. are supplied at the same time, the second line oil pressure Pf2 is lowered than the normal value. This eliminates the increase in tension on the transmission belt 44 due to centrifugal oil pressure generated in the secondary hydraulic cylinder 56 during high-speed running, improving the durability of the transmission belt 44 and reducing power loss. Further, in this embodiment, the speed specific pressure P is the second pressure regulating valve 10.
Since the second line oil pressure is supplied to the second chamber 136, there is an advantage that the second line oil pressure decrease amount increases as the speed ratio increases. In addition,
In place of the above-mentioned speed specific pressure P0, the secondary hydraulic cylinder 56
The internal oil pressure P00 or the second line oil pressure Pnz may be supplied to the boat 492a and the boat 494a of the second line oil pressure reduction control valve 380.

In the example shown in FIG. 33, the secondary hydraulic cylinder 56 internal hydraulic pressure P is applied to the boat 494a of the second line hydraulic pressure reduction control valve 380. ut or the second line oil pressure Pp, □ is supplied, and the spool valve element 498 of the second line oil pressure increase control valve 490 is controlled by the fourth electromagnetic valve 346. It is designed to be driven according to L4. As a result, when the third solenoid valve 330 is in the OFF state and the signal pressure P 1ati is not supplied to the second line oil pressure reduction control well 380, the chambers 130 and 136 of the second pressure regulating valve 102 Regardless of the operation of the rise control valve 490, both are released to the atmosphere. The signal pressure P, in relation to the third solenoid valve 330 being turned on.

1 is supplied to the second line oil pressure reduction control well 380, the speed specific pressure P1 is supplied to the chamber 130 of the second Uf4 pressure valve 102. For this reason, the second line oil pressure increase control well 490
In response to the operation of
6 internal oil pressure P. , t or the second line oil pressure Pβ.

In the example shown in FIG. 34, the boat 492a is removed from the second line oil pressure reduction control valve 380, and the boat 494a is supplied with the clutch hydraulic pressure PcL guided by the oil path 92. 492
b is connected to a chamber 502 provided on the plunger 116 side of the second pressure regulating valve 102. This chamber 502 is connected to the plunger 1 when the clutch oil pressure Pct is supplied.
16 is provided to urge the spool valve element 110 of the second pressure regulating valve 102 in the direction of increasing the second line oil pressure Pj22. Then, the chamber 13 of this second pressure regulating valve 1°2
0 is constantly supplied with the speed specific pressure P0. As a result, the third solenoid valve 330 is in the OFF state and the signal pressure P5°1
．． is not supplied to the second line oil pressure reduction control well 380, the clutch oil pressure Pel is supplied to the chamber 502 of the second pressure regulating valve 102, and the second tFI pressure valve 102 is supplied regardless of the operation of the fourth solenoid valve 346. The chamber 136 is opened to the atmosphere.

When the signal pressure P6° is supplied to the second line oil pressure reduction control valve 380 in conjunction with the third solenoid valve 330 being turned on, the chamber 502 of the second pressure regulating valve 102 is opened to the atmosphere. In this state, in connection with the operation of the fourth electromagnetic valve 346, back pressure is applied to the inside of the chamber 136 of the second pressure regulating valve 102, or clutch oil pressure PET is supplied to the inside of the chamber 136.

33 and 34, when the third solenoid valve 330 is in the off state and the fourth solenoid valve 346 is in the on or off state, as shown in FIG.
The line oil pressure Pj22 is increased from the normal value by a predetermined pressure,
During sudden braking, the speed ratios of CVTs 1 and 4 are quickly changed to the maximum deceleration side. Further, when the third solenoid valve 330 is on and the fourth solenoid valve 346 is off, the lock-up clutch 36 is engaged and the vehicle is in a normal running state, so the second line oil pressure PI! , □ are changed with normal output characteristics. Furthermore, when both the third solenoid valve 330 and the fourth solenoid valve 346 are in the ON state, the lock-up clutch 36 is engaged and the vehicle is running at high speed, so the second line oil pressure Pet is lowered from the normal value. It will be done.

In the embodiment of FIG. 35, the second line oil pressure Pffi of the second pressure regulating valve 102 is associated with one control valve.

The rise and fall of

That is, the second pressure regulating valve 102 is provided with a plunger 510 that can come into contact with one end of the spool valve 110, and a chamber 130 and a chamber 512 located on the opposite side of the plunger 510. The second line oil pressure increase/decrease control valve 514 is supplied with a boat 516a, a drain boat 516b, and a signal pressure P, which are supplied with the speed specific pressure P guided by the oil passage 86. , 3 is supplied with boat 516
c and chamber 517, boat 516d connected to chamber 130 of second pressure regulating valve 1.02, chamber 512 of second pressure regulating valve 102
A boat 516e connected to the boat 516e, a spool valve 518 that switches the connection between the boats, and a spool valve 518
It is provided with a spring 520 for biasing in one direction. As a result, as shown in FIG. 38, 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 urging force of the spring 520. Room 13
0 and 512 are set to atmospheric pressure, and the second line oil pressure P12 is increased from the normal value. In addition, the third solenoid valve 33
0 is in the on state, a signal pressure P is applied to the end surface of the spool valve 518. 13 is in play.

Therefore, when the third solenoid valve 330 is in the on state and the fourth solenoid valve 346 is in the off state, the spool valve element 518 is moved against the urging force of the spring 520, so that the second #A pressure valve 102 is moved. The speed specific pressure P is supplied to the chamber 130, the chamber 512 is set to atmospheric pressure, and the second line oil pressure P1z is set to a normal value. When both the third solenoid valve 330 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 reaches atmospheric pressure. At the same time, a signal pressure P is applied to the chamber 512. , 3 are supplied, and the second line oil pressure PI! , t is lowered.

In this manner, the tension of the transmission belt 44 can be suitably controlled in any of the embodiments shown in FIGS. 31 to 35 described above.

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

For example, steps 5S20 and SS of the above embodiment
In step 21, it is determined whether the vehicle condition is within the second line oil pressure drop region for correcting the centrifugal oil pressure based on the vehicle speed ■, the throttle valve opening θ, and the input shaft rotation speed N in. However, instead of changing the throttle valve opening θ,
The required output amount such as the intake air amount of the engine 10, the smoke material injection amount, the accelerator pedal operation amount, etc. may be used. Also, the speed ratio e is output shaft rotation speed N, uL/input shaft rotation speed N. In addition, the vehicle speed (■) is the output shaft rotational speed N. Since it corresponds to ut, whether or not it is within the second line oil pressure drop region is determined based on the throttle valve opening θ, the speed ratio e, and the input shaft rotation speed N8□. Based on θ, speed ratio e, and output shaft rotational speed Nout, or based on throttle valve opening θ, input shaft rotational speed N in,
and output shaft rotation speed N. It is substantially the same even if it is determined based on ut.

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. Hydraulic control of a type in which the speed ratio of the CVT 14 is changed by constantly supplying hydraulic oil to the primary side hydraulic cylinder 54 using a speed change control valve, or by discharging hydraulic oil from the secondary side hydraulic cylinder 54. It may also be a circuit.

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

In addition, in the speed change control of the CVT 14 in the above-described embodiment, the actual input shaft rotation speed N
Although the speed ratio e
= N ouL/N in , therefore, it is substantially the same even if the speed ratio e is controlled to be adjusted so that the actual speed ratio e matches the target speed ratio e1.

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 drawings]

FIG. 1 is a detailed circuit diagram of a hydraulic control system for operating the device of FIG. 2. FIG. 2 is a schematic diagram showing a vehicle power transmission device equipped with a hydraulic control device according to an embodiment of the present invention. FIG. 3 is a diagram showing the second pressure regulating valve of FIG. 1 in detail. FIG. 4 is a diagram showing the first pressure regulating valve of FIG. 1 in detail. FIG. 5 is a diagram showing the output characteristics of the throttle valve opening detection valve shown in FIG. 1. FIG. 6 is a diagram showing the output characteristics of the speed ratio detection valve shown in FIG. 1. FIG. 7 is a diagram showing the output characteristics of the second pressure regulating valve shown in FIG. 3. FIG. 8 is a diagram showing ideal characteristics of the second line oil pressure. FIG. 9 is a diagram showing in detail the configuration of the speed change control valve device shown in FIG. 1. FIG. 10 is a diagram illustrating the relationship between the operating states of the first solenoid valve and the second solenoid valve in the speed change control valve device of FIG. 9 and the shift state of the CVT shown in FIG. 2. 11, 12, and 13 are diagrams for explaining the relationship between the speed ratio of the CVT shown in FIG. 2 and the oil pressure value of each part, and FIG.
FIG. 2 shows an engine brake running state, and FIG. 13 shows an unloaded running state. FIG. 14 is a diagram showing the output characteristics of the 111th pressure valve in FIG. 4 with respect to the primary side hydraulic cylinder internal oil pressure or the second line oil pressure. FIG. 15 is a 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. 1st
Figure 6 shows the solenoid pressure switching valve of the hydraulic control circuit in Figure 1;
It is a figure explaining a 4th pressure regulating valve etc. in detail. Figure 17 shows
FIG. 2 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 diagram illustrating the second line oil pressure that changes in relation to vehicle speed (centrifugal oil pressure). FIG. 19 is a flowchart illustrating the operation of the control device of FIG. 2. Figures 20 and 21 are
FIG. 6 is a diagram showing the relationship between the duty ratio of the second electromagnetic valve and the flow rate that is continuously changed in relation to the duty ratio,
FIG. 20 shows the characteristics when the speed ratio of the CVT is changed toward the deceleration side, and FIG. 21 shows the characteristics when the speed ratio of the CVT is changed toward the speed increase side. FIG. 22 is a flowchart 1 for explaining the routine constituting step S9 in FIG. 19. FIG. 23 shows the third control mode in control modes (A), (B), (C), (D), and (E).
It is a figure which shows the operating state of a solenoid valve and a 4th solenoid valve. FIG. 24 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. FIG. 25 is a data map showing the relationships used in step S20 of FIG. 22. FIG. 26 is a diagram showing the output torque characteristics of the engine shown in FIG. 2. FIG. 27 is a diagram showing the margin oil pressure ΔP of the second line oil pressure at a constant throttle valve opening of the vehicle shown in FIG. FIG. 28 is a diagram showing a state of decrease in the second line oil pressure.
FIG. 9 is a diagram illustrating the relationship between the excess oil pressure ΔP and the actual value ΔP' for reducing it by that amount, and FIG. 30 is a diagram corresponding to FIG. 27 showing the above-mentioned ΔP' at a constant throttle valve opening. It is. 31, 32, 33, 34, and 35 are diagrams that do not show the main parts of the hydraulic circuit of other embodiments of the present invention, and FIGS. 36, 37, FIG. 38 is a chart illustrating operating conditions for second line oil pressure increase and decrease control in the embodiments of FIGS. 32, 33, 34, and 35, respectively. 14: CVT (belt type continuously variable transmission) 40° 42: Variable pulley 44: Transmission belt 54X - next side hydraulic cylinder (hydraulic actuator) 56
Secondary side hydraulic cylinder (hydraulic actuator) 102:
Second pressure regulating valve (pressure regulating valve) 110 Nisbourg valve 136: Chamber 330: Third solenoid valve (pressure reducing hydraulic signal generating means) 346
: 4th solenoid valve (hydraulic signal generation means for pressure reduction) 380: 2nd
Line oil pressure drop control valve (hydraulic signal generation means for pressure reduction) 460: Electronic control device (judgment means, oil pressure signal generation means for pressure reduction) 514: 2nd line oil pressure rise and fall control valve Fig. 3 (PSO14) Fig. 5 Fig. 6 Figure Speed Ratio e (Husband) Far Hama Ratio e (Phantom Figure 14 Figure 15 'Fu, Ko-I-Eye-L) s4 Speed Ratio ε (Loss) Figure 24 η Darkness 0 Temperature Eyebrow V to J No. 25th prisoner 26th prisoner/v'jne hh") Vehicle speed V - (Waut) Fig. 28 Fig. 29 Fig. 29 Ear... Figure 37

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 biasing force applied to the spool valve element in the direction of decreasing the pressure regulation value. a pressure regulating valve having a chamber that receives a pressure reducing oil pressure signal for the purpose of reducing the pressure; determining means for determining whether or not the vehicle is within the range; and when the determining means determines that the running state of the vehicle is within the range, generating the pressure reducing oil pressure signal to the chamber of the pressure regulating valve; A hydraulic control device for a belt-type continuously variable transmission for a vehicle, characterized in that the hydraulic control device includes: a hydraulic pressure signal generating means for supplying a pressure reducing hydraulic pressure;