JPH03255254A - Hydraulic controller for continuously variable transmission - Google Patents

Abstract

PURPOSE:To prevent a belt from slippage under any condition of recovery by connecting a lock lever to one valve body of a switch valve, and energizing a spring for setting a line pressure to high one to the other in the change-over of a tire lock to the drain side. CONSTITUTION:In a control system of an continuously variable transmission a valve body 172 of a switch valve 170 is normally changed over to the line pressure side by a lock lever 175. The line pressure is introduced into a balance chamber 91c of a line pressure adjusting valve 90 to control the line pressure according to change gear ratio or the like. Also in tire locking, the balance chamber 91c of the line pressure adjusting valve 90 communicates to the drain side through the valve body 172 of the switch valve 170, and the line pressure is adjusted to high pressure by a spring 173 of the switch valve 170. Thus, in the recovery of a tire lock, high line pressure is always ensured so that the secondary pulley side belt can be surely prevented from slippage.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a hydraulic control device that mechanically controls line pressure and speed change in a belt-type continuously variable transmission for vehicles. This invention relates to measures to prevent belt slip in the event of tire lock during braking on roads such as µ-roads.

[Conventional technology]

Regarding hydraulic control of this type of continuously variable transmission, various proposals have already been made, including a gear ratio control valve that changes speed based on factors such as accelerator opening and engine speed, and a line pressure control valve that controls line pressure based on factors such as the gear ratio. It is equipped with regulating valves, etc. Here, each of these valves is based on the premise that the tires grip the road surface when the vehicle runs, and that the rotational state of the wheels is smoothly fed back to the engine rotational speed along with the primary torque via the gear ratio. Therefore, if the tires lock up during braking on a low μ road such as a snowy road and the vehicle skids, the pulleys and belts together with the wheels rapidly decelerate and come to a stop. For this reason, the control of each valve in the hydraulic control system cannot follow the deceleration state in this case and becomes temporarily abnormal, which causes the shift control and line pressure control to become abnormal when the brake is released and recovered. Belt slip is likely to occur due to imbalance. From this, it may be possible to accurately determine abnormal driving conditions such as tire locking and take measures to prevent belt slip when the brakes are released to recover.

Conventionally, in the hydraulic control system of the above-mentioned continuously variable transmission, there is a prior art, for example, Japanese Patent Application No. 63-240432 filed by the applicant of the present invention, regarding measures to prevent belt slip when the tires are locked. Here, when the tires are locked, as the pitot pressure decreases according to the engine speed, the primary pressure is controlled to the lowest speed gear, even though the actual pulley and belt are locked to the high gear side. We are focusing on Therefore, tire lock is detected based on the gear ratio and pitot pressure, and in this case, the shift lock valve on the drain side of the gear ratio control valve is closed to maintain the primary pressure at high pressure.
Fix the gear ratio to the high speed side.

It has been shown that when the pulley and belt suddenly recover when the brake is released, belt slip can be prevented by strengthening the pressing force of the primary system pulley, which has a large inertial mass.

[Problem to be solved by the invention]

By the way, in the prior art described above, only the primary pressure is controlled to a high pressure, and the line pressure remains unchanged. Here, in the case of recovery by releasing the brake, the function of the shift lock valve is canceled due to the generation of pitot pressure, the primary pressure quickly decreases, and a downshift is performed. Further, the line pressure is controlled to increase rapidly in response to the downshift, and at this time, the secondary pressure is increased while rapidly increasing the volume of the hydraulic chamber of the secondary pulley. Therefore, under conditions such as when the engine speed and the pump discharge amount are large when the tires are locked, or when the line pressure is relatively high on the low gear side, the line pressure rises quickly when the shift lock is released, even with the prior art. can be adequately dealt with.

However, if the engine speed drops to idling speed when the tires are locked, the shift locks on the overdrive side, or if you stop and restart with the tires locked, the line pressure will suddenly increase when the shift lock is released. is delayed. Therefore, when the tires are locked under such conditions,
When returning, belt slip may occur due to insufficient line pressure.

The present invention has been made in view of the above, and its purpose is to optimally control the line pressure as well as the primary pressure when the tire is locked, thereby reliably preventing belt slip during recovery under any conditions. The object of the present invention is to provide a hydraulic control device for a continuously variable transmission.

[Means to solve the problem]

In order to achieve the above object, the hydraulic control device for a continuously variable transmission of the present invention provides a boat in which a line pressure regulating valve drains a predetermined amount of line pressure to regulate the pressure. In a hydraulic control system that controls line pressure by having balance chambers that act in opposition to each other, an on-off valve is installed in the oil passage of the balance chamber of the line pressure regulating valve to introduce or cut off line pressure and communicate with the drain side. A lock lever is connected to one of the valve bodies of the above-mentioned on-off valve to enable switching to the drain side when the tires are locked, and a spring is attached to the other side to set the line pressure to a high pressure when the tires are switched to the drain side. It is something that strengthens.

[Function] Based on the above configuration, in the hydraulic control system of the continuously variable transmission, under normal conditions, the valve body of the on-off valve is switched to the line pressure side by the lock lever, and line pressure is introduced into the balance chamber of the line pressure regulating valve. The line pressure is controlled according to the gear ratio, etc. In addition, when the tires are locked, the balance chamber of the line pressure regulating valve is communicated with the drain side by the valve body of the on-off valve, and the line pressure is regulated to a high pressure by the spring of the on-off valve, thereby recovering the tire lock. At times, high line pressure is always ensured to reliably prevent belt slibbing on the secondary pulley side.

〔Example〕

Embodiments of the present invention will be specifically described below based on the drawings.

Referring to FIG. 1, a belt-type continuously variable transmission based on a front engine/front drive (FF) with a transverse transaxle and an electromagnetic powder clutch will be described.

Reference numeral 1 is an electromagnetic powder clutch, 2 is a forward/reverse switching device, 3 is a continuously variable transmission, and 4 is a front differential device. The electromagnetic powder clutch 1 is housed in one side of the clutch housing 6, and the other side of the clutch housing 6 includes a main case 7 joined thereto, and a side case joined to the opposite side of the main case 7 from the clutch housing 6. 8 has a forward/reverse switching device 2. Continuously variable transmission 3. A front differential device 4 is housed therein.

The electromagnetic powder clutch l includes a ring-shaped drive member 12. which is integrally connected to the engine crankshaft lO via a drive plate 11. A disc-shaped driven member 1 that is integrally spline-coupled to the transmission input shaft 3 in the rotational direction.
It has 4. A coil 15 is built in the outer peripheral side of the driven member 14, and a gap 16 is formed along the circumference between the drive member 12 and the driven member I4, and this gap 16 contains electromagnetic powder. Also coil 15
A power feeding brush I9 is in sliding contact with the slip ring 18 of the hub portion of the driven member 14, which is provided with a power supply brush I9.
5 to form a clutch current circuit.

In this way, when the clutch current is applied to the coil 15, the drive and driven member 12.1 are connected through the gap 16.
4, electromagnetic powder is combined and accumulated in the gap 16 in a chain shape, and the resulting binding force causes the driven member 14 to slide and integrally connect to the drive member 12, resulting in a clutch connected state. . On the other hand, when the clutch current is cut, the drive by electromagnetic powder and the coupling force between the driven members 12 and 14 are lost, resulting in a clutch disconnected state.

If the clutch current in this case is controlled in conjunction with the operation of the forward/reverse switching device 2, it is possible to switch from the P (parking) or neutral to N range to the forward D (drive) or Ds (sporty drive) range. or R of retreat (
When switching to the reverse (reverse) range, the clutch l is automatically connected and disconnected, eliminating the need for clutch pedal operation.

Next, the forward/reverse switching device 2 includes an input shaft 13 from the clutch 1 and a primary shaft 20 disposed coaxially therewith.
established between. That is, the input shaft 13 is formed with a reverse drive gear 21 that also serves as a forward engaged side, and a reverse engaged side gear 22 is rotatably fitted to the primary shaft 20. 21 and 22 are counter gears 24 supported by a shaft 23. They are meshed through an idler gear 26 supported by a shaft 25. A switching mechanism 27 is provided between the primary shaft 20 and the gears 21 and 22. The above gear 21.2 which is always in mesh here
4.26.22 is connected to the driven member 14 having the coil 15 of the clutch l, and corresponding to the fact that the inertia mass of this part is relatively large when the clutch is disengaged, the switching mechanism 27 is connected to the driven member 14 having the coil 15 of the clutch l. The sleeve 29 that is spline-fitted to the hub 28 is the synchronizer Ill! 30, 31 to be meshed and connected to each gear 21 and 22.

As a result, in the neutral position of P or N range, the switch l
The sleeve 29 of II27 is fitted only with the hub 28, and the primary shaft 20 is separated from the human-powered shaft I3. Next, when the sleeve 29 is meshed with the gear 21 side via the synchronizing mechanism 30, the primary shaft 20 is directly connected to the human power shaft 13, resulting in a forward movement state in the D or Ds range.

On the other hand, when the sleeve 29 is meshed with the gear 22 side via the synchronizing mechanism 31, the input shaft 13 is connected to the gear 21°2.
4, connected to the primary shaft 20 via 26.22,
The engine power is reversed and the R range is in reverse mode.

In the continuously variable transmission 3, a secondary shaft 35 is arranged parallel to the primary shaft 20, and primary pulleys 36. A secondary pulley 37 is provided, and an endless drive belt 34 runs between both pulleys 36,37. Primary pulley 3
B. The secondary pulleys 37 are each divided into two parts, and one of the fixed pulleys 36a and 37a is movable, while the other movable pulleys 36b and 37b are movable to make the pulley interval variable. is equipped with a hydraulic servo device [38, 39 which also serves as a piston, and furthermore, the movable pulley 37b of the secondary pulley 37 has a
A spring 40 is biased in a direction to narrow the pulley interval.

Further, as a hydraulic control system, an oil pump 41 as an operating source is installed next to the primary pulley 36. This oil pump 41 is a high-pressure gear pump, and the pump drive shaft 42 is connected to the primary pulley 36. It penetrates through the interior of the primary shaft 20 and the input shaft 13 and is directly connected to the crankshaft 10, so that hydraulic pressure is constantly generated during engine operation. Then, the oil pressure of the oil pump 41 is controlled to supply and drain oil to each hydraulic servo device 38, 39, and the pulley spacing between the primary pulley 36 and the secondary pulley 37 is changed to an inverse relationship, so that the pulley 3B of the drive belt 34 , 37 are converted steplessly, and steplessly variable power is output to the secondary shaft 35.

In view of the fact that the minimum boolean ratio on the high speed side of the continuously variable transmission 3 is very small, for example 0.5, and therefore the rotational speed of the secondary shaft 35 is high, the front differential device 4 is An output shaft 44 is connected via a pair of intermediate reduction gears 43a and 43b. A final gear 46 meshes with the drive gear 45 of this output shaft 44, and transmission is configured from the final gear 4B to the left and right front wheel axles 48a, 48b via a differential mechanism 47.

In FIG. 2, the hydraulic control system of the continuously variable transmission 3 will be explained. In the primary hydraulic servo device 38, a movable pulley 3fib is fitted into a cylinder 38a that is integrated with the primary shaft 20, and supply and exhaust are supplied and discharged into the cylinder 38a. Primary pressure is generated by oil.

Also, in the secondary hydraulic servo device 39, a movable pulley 37 is attached to a cylinder 89a that is integrated with the secondary shaft 35.
b is fitted, and line pressure is introduced into the cylinder 39a. Here, the movable pulley 3Bb has a larger pressure receiving area than the movable pulley 37b, making it possible to perform speed change control using only the primary pressure.

The oil pumped up from the oil reservoir 70 by the oil pump 41 is passed through the oil passage 71a to the line pressure regulating valve 90.
A line pressure oil passage 71 that is guided by the oil passage 71a and branches from the oil passage 71a.
b communicates with the secondary cylinder 39a to always introduce line pressure. An oil passage 71c branching from the oil passage 71a communicates with a gear ratio control valve 100.
An oil passage 72 communicates between the primer cylinder 38a and the primer cylinder 38a. In addition, a pitot pressure sensor 73 is installed at the primary cylinder 38a to take out a pitot pressure as a control pressure according to the engine speed during shift control after clutch engagement, and the pitot pressure from this pitot pressure sensor 73 is , line pressure regulating valve 90 . Gear ratio control well 10
It leads to 0.

Furthermore, in contrast to the D range, which performs shift control over a wide range including low engine speeds, the hydraulic pressure control is limited to a high engine speed range to obtain the Ds range, which applies engine braking when the accelerator is released. As a system, a relief valve 76 is provided in the drain oil passage 75a from the line pressure adjustment valve 90, and an oil passage 75b of the lubrication hydraulic circuit that branches from the upstream side of the relief valve 76 communicates with the select position detection valve 130. Oil passage 75 further branches from oil passage 75b
c communicates with the engine brake actuator 140 of the gear ratio control valve 100.

Oil passage 75d branching from oil passage 75a of the lubrication hydraulic circuit
is a belt lubricating nozzle 7 arranged on the inner circumference of the belt 34
7, the oil passage 75e communicates with the oil supply lower 8 of the pitot pressure sensor 73, and the oil passage 75e communicates with the oil reservoir 70 via the check valve 79° oil cooler 80. A balancer chamber 3 is located on the opposite side of the hydraulic chamber 39b of the secondary cylinder 39a.
9e is provided, and the outlet side oil passage 81 of the oil tank 80 communicates with the balancer chamber 39c and fills it with oil.
The centrifugal oil pressure of 9b is offset by the balancer chamber 39c. In addition, the drain oil passage 82 of the gear ratio control valve I00
A shift lock valve 8 is provided with a check valve 83 in the middle of the shift lock valve 8.
4 are provided, and the oil passages 82 and 75 upstream of the check valve 83
A pre-feeling oil passage 85 communicates with b.

In addition, in the middle of each oil route.

An orifice 8B is provided in the atmospheric opening.

The line pressure regulating valve 90 has a spring 94 biased between the valve body, a spool 92°, and one bush 93 of the spool 92, and engages with the primary town pulley 36b to adjust the actual gear ratio. A sensor shoe 95 for detection is movably supported by a shaft tube 96 that also serves as a lubrication passage and connected to a bush 93. In the valve body 91, the pitot pressure of the oil passage 74 acts on the boat 91a on the opposite side of the spring 94 of the spool 92, and on the right side of this boat 91a there is a drain boat holder, and further a balance chamber 91c is arranged.
Normally, line pressure acts on the balance chamber 91c. Also, a boat 91 to which line pressure is introduced next to the boat 91c.
d and a drain port 91e, and the land chamfer part 92a of the spool 92 changes the drain amount to regulate the pressure.A two-stage line pressure switching boat 91f is provided on the spring 94 side next to the drain boat 91e. is provided.

On the other hand, a line pressure two-stage switching solenoid valve 97 is provided in the line pressure oil passage 71c. This two-stage line pressure switching solenoid valve 97 is a three-way valve, and selectively communicates the oil passage 98 connected to the two-stage line pressure switching boat 91f with the oil passage 71c side and the drain side, so that when energized, Port 9 for line pressure two-stage switching by connecting oil passages 71c and 98
The line pressure is introduced to 1f, and the oil passage 98 is communicated with the drain side when no electricity is applied.

In this way, the spring force of the spring 94 of the spool 92 increases as the gear ratio increases, and this spring force acts on the line pressure increasing side. Further, the line pressure of the balance chamber 91c and the line pressure two-stage switching boat 91r acts on the line pressure decreasing side, and the line pressure is controlled by the balance between these two. The pitot pressure at the end of the spool 92 changes when the pump discharge amount changes with the engine speed.
It acts to adjust the balance point of

Therefore, the spring force F at the balance point of the spring 94 is
, the line pressure PL, and the pressure receiving area difference between the balance chamber 91c and the line pressure two-stage switching port 91r are AL.

Assuming that Ac is, when the line pressure two-stage switching solenoid valve 97 is de-energized, AI,·PL-F is established, and the line pressure is controlled at a high pressure by PL-F/AL.

Moreover, when the solenoid valve 97 is energized, (AL +Ac
)・PL-F is established, and the line pressure is PI, -F/(AL +Ac)
Controlled by low pressure. In this way, the line pressure is steplessly controlled by a spring force that changes according to the gear ratio, and the line pressure level is controlled in two stages, low and high, by the two-stage line pressure switching solenoid valve 97, so that the boolean is pressed. It begins to generate power.

The gear ratio control valve 100 has a spool 102 on one side of a valve body 101, and a boat ■01a at one end of the spool 102.
The pitot pressure is checked by check valve 103 or orifice 10.
4, and a low speed spring 105.4 at the other end. High speed spring 106 is biased.

In addition, the boat 101b in the center of the spool 102 is connected to the oil passage 72.
The left and right boats 101c and 101d are drain oil passages 82. The spool 102 communicates with the line pressure oil path 71c.
is supplied to the primary cylinder 38a through the groove portion 102a,
It is designed to drain oil and generate primary pressure.

The other side of the valve body +01 has a plunger 107, and one end of a rod 108 is connected to the plunger 107 with a spring 1.
09, and roller 1 at the other end of the rod 10g.
Shift cam 11 rotates according to the accelerator opening at 08a.
0 comes into sliding contact. A guide itt is attached to the plunger 107 and receives the spring 105, thus changing the force of the spring 105 in accordance with the rotation of the shift cam 110. Here, the plunger 107 has an oil passage 74.
The pitot pressure is guided, and the spring reaction force acting on the plunger 107 is received by the pitot pressure, and the shift cam Ill
The system is designed to reduce the operating force required.

Furthermore, a mechanical modulator mechanism 120 is provided between the plunger 107 and the spring 106.

This modulator mechanism 120 has a variable mechanism 121 between the plunger 107 and the receiver 112 of the spring 106 inside the guide 111, and the variable mechanism 121 is connected to the sensor shoe 95 via a sink 122.

Then, the variable mechanism 121 operates as a modulator to gradually increase the force of the spring 10B as the gear ratio shifts to a high speed gear.

In this way, the spool 102 has the pitot pressure and the shift cam 1
The force of the spring 105 is applied according to the accelerator opening degree. A predetermined primary pressure is generated by the balance between the two to determine the gear ratio, and the gear ratio is controlled to upshift to a high speed gear as the pitot pressure increases with the increase in vehicle speed. At this time, the modulator mechanism 120 further applies a force of the spring 106 in accordance with the gear ratio to the spool 102, thereby gradually increasing the engine speed in accordance with the upshift to the high speed gear.

The select position detection valve 130 has a valve body 131 inserted with a valve body 133 having a drain hole 132, and a cam 13 that rotates in accordance with the operation of a select lever 136.
5 is the contact. Here, in the cam 135, D, N
, R range position is the convex portion 135a, and P and D at both ends
The range position of s is in the fourth part 135b, and as above,
Drain holes 132 are closed in each of the N and H ranges to generate operating oil pressure. Furthermore, when the P and Ds cylinder drain holes 132 are opened, the orifice 86 prevents the oil pressure in the upstream oil passage 75a from decreasing.

The engine brake actuator 140 has a piston 142 inserted into a cylinder 141.
A return spring 143 is biased to one side of the piston chamber 2, and the operating hydraulic pressure of the oil passage 75b is guided to the other piston chamber 144 via the oil passage 75c. Also, the hook 142a at the tip of the piston 142, the rod 108 of the gear ratio control valve 100,
between the roller pin 108b and the sensor shoe 95,
A lever 14B of a modifying mechanism 145 for correcting Ds range characteristics, which also serves as a push lever, is provided so as to be engageable.

In this way, when there is no P, Ds cylinder operating oil pressure, the lever 146 is swung by the hook 142a of the piston 142 to forcibly push the rod 10B to a predetermined stroke, thereby limiting the speed change range to the high engine speed side. This causes the Ds cylinder to act as an engine brake. When a predetermined gear ratio is reached in this state, the sensor shoe 95 engages with the lever 14B, and from this point on, the sensor shoe 95 swings the lever 14B in the opposite direction as the gear ratio increases, and the piston 142 rod 108 is pulled back to the forward dimension position.

2 and 3, measures to prevent belt slip when tires are locked will be described.

During recovery after this tire lock, belt slip may occur due to a drop in primary pressure and insufficient line pressure, and to deal with this, it is necessary to maintain both the primary pressure and line pressure at high pressures. First, we will discuss measures to maintain the primary pressure at a high level when the tires are locked.

In FIG. 3, numeral 150 is a valve block;
The body 151 and plate 1 of this valve block 150
A line pressure regulating valve 9G shown in FIG. 2 is installed inside and outside of 52.

Gear ratio control valve 100. Modulator mechanism 120. A modification mechanism 145 is installed, and a shift lock mechanism H is also installed to prevent belt slip when the tires are locked.
Ij160 is provided.

As already mentioned, the shift lock mechanism 160 has a shift lock valve 84 attached to the check valve 83 of the drain oil passage 82 from the gear ratio control valve 100, and a shift lock valve 84 on the side opposite to the shift cam 110 of the valve block 150. A plunger 161 is installed on the same side as the valve 84. And these shift lock valves 84. A shift lock arm 165 is mounted between the plunger tet and the sensor shoe 95.

The check valve 83 is connected to the spool 84 of the shift lock valve 84.
A ball 83C biased by a spring 83b is provided inside the cylinder b to regulate the amount of drain from the drain oil passage 82, and when the primary cylinder 38a is drained at the maximum gear ratio, it is filled with oil and prefilled. It is something that works.

Further, the spool 84b of the shift lock valve 84 is movably inserted into the cylinder 84a of the shift lock valve 84 to open and close the drain port 84c.

Further, from the cylinder 84a, a boat shaft 84g is connected to a spring receiver 84f that is integrated with a spool 84b of the shift lock valve 84.
It is installed so that it is in contact with the Here, the spring receiver 84f includes the inside of the spool 84b and the boat shaft 84.
A communication hole 84h is provided that communicates the side that contacts the shift lock valve 84, and since oil flows into the inside of the spool 84b of the shift lock valve 84, the boat 8 that drains this oil
4d and 84e are provided on the cylinder 84a and spool 84b of the shift lock valve body 84, and these boats 8
4d.

84e coincide with the drain port 84c of the cylinder 84a formed opposite the ball 83c of the check valve 83 when the drain port 84c is in the open position, but are set in a relationship that does not match when the drain port 84c is in the closed position. In the closed position of the drain port 84C, high primary pressure is applied behind the spool 84b of the shift lock valve 84 to self-lock the port shaft 84C.
The self-lock is configured to be released by the drain from g.

The plunger 161 is inserted into a cylinder 162 that communicates with the pitot pressure oil passage 74, and moves according to the pitot pressure to detect its magnitude. At a relatively large normal pitot pressure in the high speed stage, the tip 161a of the plunger 161
protrudes higher than the body 151.

The shift lock arm 1135 has a parallel connecting portion 165a.
Shift lock valve 84. It has an engaging piece 185b for engaging the plunger 161, and an engaging piece 165d for engaging the spring receiver 165C and the sensor shoe 95 on the other side. The connecting portion 165a is swingably attached using, for example, the shaft 123 of the modulator mechanism 120, and a spring 166 is biased against the spring receiver 185c. Engagement piece 1
65d extends directly below the sensor shoe 95, and at a gear lower than a predetermined gear ratio is (for example, 1.0), the straight portion 165e engages with the pin 95a on the sensor shoe 95 side, causing the arm 165 to swing. limit. Also, this gear ratio is 1s
At higher speeds, the restriction by the sensor shoe 95 is released, and if the pitot pressure drops abnormally under these conditions, it is determined that the tires are locked during braking on a low μ road, and the arm 165 is activated. Furthermore, a taper 165'' is provided at the tip of the engagement piece 185d so that the sensor shoe 95 can be moved to return the bin 95a to the arm 165.

The arm 165 is normally tilted by the action of the plunger 161 or the sensor shoe 95, and is set to be horizontal by the spring 166 when the tire is locked. Normally, when the adjusting screw 167 is tilted together with the arm 165, the biasing force of the spring 83b of the check valve 83 causes the spring receiver 84r to move with the spool 84b of the shift lock valve 84.
moves to open the drain boat 84c, and the spring receiver 84r comes into contact with the port shaft 84g. On the other hand, arm 16
5 is horizontal, the port shaft 8 is adjusted via the adjusting screw 167.
4g and spring receiver 84'' are pushed in, and the spool 84
b moves to close the drain port 84c, and in this state, the oil inside the spool 84b flows into the spring receiver 84.
It flows into the boat shaft 84g side through a communication hole 84h formed in f.

When the arm 165 is released from the horizontal state and begins to tilt, the contact portion between the spring receiver 84f and the port shaft 84g opens, and the oil is drained through the inside of the boat shaft 84g.

Next, we will discuss measures to maintain high line pressure as a measure to prevent belt slip when the tires are locked. this is,
The line pressure regulating valve 90 utilizes line pressure control using oil pressure in the balance chamber 91c, and an on-off valve 170 is installed between the line pressure boat 91d and the balance chamber 91c in the valve body 91.

The on-off valve 170 is inserted between the balance chamber 91c, the boat 91d, and the drain boat 171 so that the valve body 172 moves to switch the flow path, and a spring 173 is biased toward the drain side of the valve body 172.

Further, in order to operate the on-off valve 170 depending on whether or not the tire is locked, a lock lever 1 having a return spring 174 is provided on the opposite side of the valve body 172 from the spring 173.
75 is provided so as to be engageable. The engagement piece 165b of the shift lock arm 165 is connected to the lock lever 175 via the rod 176, and when the tire is locked, the on-off valve 17
0 valve body 172 is moved to communicate the balance chamber 91c with the drain side, and the line pressure is regulated to a predetermined high pressure balanced with the spring 173. On the other hand, when recovering from a tire lock, the spring 9 is activated by the sensor shoe 95 as the downshift occurs.
4 increases and returns to its original state when the line pressure exceeds the set value.

Next, the operation of the continuously variable transmission control system configured as described above will be explained.

First, before the vehicle stops or starts shifting at the start of running, the line pressure regulated by the line pressure regulating valve 90 is introduced only to the secondary cylinder 39a through the oil passage 71b, and the primary cylinder 38a is introduced to the gear ratio control valve 100. It communicates with the drain oil passage 82 by. Therefore, in the continuously variable transmission 3, the diameter of the winding of the secondary pulley 37 around the primary pulley 36 of the drive belt 34 is the largest, and the maximum gear ratio i
It becomes L low gear.

Next, after driving, the pitot pressure of the pitot pressure sensor 73 increases and the spool 102 of the gear ratio control valve 10 (l) is moved.
When the line pressure of the oil passage 71c is supplied to the primary cylinder 38a via the oil passage 72, a prefill action immediately generates primary pressure and starts an upshift. As the primary pressure increases, the diameter of the winding of the drive belt 34 around the primary pulley 36 increases, and finally the speed is continuously changed to a high speed stage with the minimum gear ratio iH.

Therefore, in the above-mentioned speed change control, in the low gear stage, as shown in FIG. 3, the engagement piece 165d of the shift lock arm 165 engages with the pin 95a of the sensor shoe 95 in the shift lock device 1 teo, and the rocking is restricted. Therefore, when the vehicle is stopped and the pitot pressure is zero, or when the vehicle is traveling at low speed and the pitot pressure is small, the shift lock arm 165 is held tilted. Therefore, the boat shaft 84 of the shift lock valve 84
g protrudes outward, and the spool 84b is connected to the drain boat 84.
Move backward to open c to enable draining. Therefore, even when the primary cylinder 38a of the gear ratio control valve 100 is communicated with the drain oil passage 82 by the boats 1o1b and 101c, the shift lock valve 8 is connected via the check valve 83.
The oil is freely drained from the drain boat 84c of No. 4 to reach the maximum gear ratio, and as the primary cylinder 38a is refilled with oil after the vehicle is running and the primary pressure increases, the gear ratio is upshifted from the maximum gear ratio. In this way, it is ensured that the gear change control in the low gear is always performed normally.

Then, as the vehicle speed increases and the pitot pressure corresponding to the engine speed increases, the plunger 181 is strongly pushed out by the pitot pressure to maintain the shift lock arm I65 in the above-mentioned inclined state. Therefore, even after the pin 95a of the sensor shoe 95 moves to the right in FIG. This makes it possible to drain water from the drain boat 84c and to freely perform gear changes such as kickdown. Also, if you downshift when decelerating,
The sensor shoe 95 moves to the left side in FIG.
5a engages with the shift lock arm] 65 and returns to the above state.

On the other hand, when the shift lock arm 165 is tilted as described above, the on-off valve 17 in the line pressure regulating valve 90 is
The valve body 172 of 0 is held by a lock lever 175 at a position where the balance chamber 91c and the boat 91d are communicated with each other. Therefore, the line pressure PL of the boat 91d is introduced into the balance chamber 91c and acts on the spool 92, and the line pressure is controlled so as to be balanced with the force of the spring 94 depending on the gear ratio. A boolean pressing force corresponding to the transmitted torque is applied by the line pressure PL to prevent belt slip and reduce pump load and fuel consumption.

Next, in a high speed gear such as the minimum gear ratio, the shift lock arm 1.65 comes off from the sensor shoe 95 and can swing, and under this condition, when braking on a low μ road, the shift lock arm 1.65 becomes detached from the sensor shoe 95 and can swing as shown in Fig. 5 (a).
, (b), when the pitot pressure pt suddenly decreases with the wheel speed Vv and the tire locks, the amount of thrust of the plunger 161 decreases and the shift lock arm 165 is moved approximately horizontally by the spring 166 as shown in FIG. Swinging in state. Therefore, the shift lock valve 84 pushes down the spool 84b via the boat shaft 84g to close the drain boat 84c, and the boat shaft 84g and the spring receiver 84
The contact portion f is also closed by movement of the adjusting screw 187. Therefore, even if the gear ratio control valve 100 connects the primary cylinder 38a to the drain oil passage 82 due to a decrease in pitot pressure, the high shift lock pressure Pa remains upstream of the shift lock valve 84 as shown by the broken line in FIG. 5(c). Contained on the side. Thus, the primary pulley 36. Secondary pulley 37 and belt 3
4 is stopped and held on the high speed side due to tire lock and the shift is locked, and in the hydraulic control system, the primary pressure Pp of the primary cylinder 38a is set to the shift lock pressure Pa.
The pressure is maintained at high pressure and the shift is locked.

In addition, at this time, in the shift lock valve 84, the ports 84d and 84e are misaligned, and the contact portion between the port shaft 84g and the spring receiver 84'' is also closed, causing the cylinder 84a to close.
The inside of is sealed. Therefore, a high primary pressure acts behind the spool 84b inside the cylinder 84a, and the check valve body 83a is thus self-locked in the closed position to ensure that the primary pressure is maintained at a high level.

The self-locking action is explained in detail using the symbols in Figure 3.
First, the inner diameter of the spool 84b of the shift lock valve 84 that covers the ball 83c of the check valve 83 is dI, and the spool 84b is
The outer diameter is d2. Port shaft 84g outer diameter d3, drain oil path 8
When the primary pressure inside 2 is Pp, the force applied to the shift lock valve 84 is (upward force) -π・dI −Pp/4 (downward force) −π・(d22 di')・P p/ 4, where π・d, 2・/4〈 π)・d22−d3')/4
If this is set, (upward force) < (downward force), and the shift lock valve 84 will self-lock.

When the brake is released, the wheel speed Vw recovers as shown in FIG. 5(a) and the secondary pulley 37 and belt 34 are rapidly rotated, but the primary cylinder 38
A high primary pressure Pp exists at point a, and in order to apply a sufficient pulley pressing force to the inertia mass on the primary pulley 36 side, the primary pulley 86 is rotated by the belt 34 without slipping, and this primary pressure pp
Maintain the gear ratio according to the After that, the pitot pressure recovers and rises, and the shift lock arm 1 is pushed out by the plunger 161.
65 is tilted, the contact portion between the port shaft 84g and the spring receiver 84'' opens, and the pressure inside the shift lock valve 84 is released.

Therefore, the drain boat 11 of the shift lock valve 84 described above
4c is released, and the spool 84b of the shift lock valve 84 is moved back by the spring 83b to open the drain boat 84C again. Along with this, the primary pressure Pp is also drained, as shown in FIG. 5(d). The downshift starts slowly and then returns.

On the other hand, when the above-mentioned tire is locked, the shift lock arm 16
5 swings horizontally as shown in FIG. 4, the lock lever 175 is disengaged from the valve body 172 of the on-off valve 170 due to the pressure of the rod 176 in the line pressure regulating valve 90.

Therefore, the valve body 172 is switched to communicate the balance chamber 91c with the drain side, and accordingly, the line pressure regulating valve 9
0, the spool 92 moves to the left even if the force of the spring 94 is small because it is on the high speed stage side, and the line pressure PL is set to the 5th stage.
It rises rapidly as shown in figure (e). Further, this line pressure PL acts on the valve body 172 of the on-off valve 170 in opposition to the spring 173, and when it becomes larger than the spring force, it acts on the balance chamber 91c to lower the line pressure, thus reducing the line pressure as shown in FIG. 5(e).
The high set pressure P' L by the spring 173 is
The pressure will be regulated and maintained.

Next, when the brake is released and pitot pressure is generated and the shift lock arm 165 returns to the inclined state, the rod 17
6 is also released, but the line pressure PL and the position of the valve body 172 of the on-off valve 170 are temporarily held in the above-mentioned state. Then, the shift lock valve 84 controls the primary pressure P.
p decreases and downshift starts, sensor shoe 95
When the force of the spring 94 becomes larger than that of the on-off valve 170 due to the movement of
'L, the valve body 172 returns to its original position, and the lock lever
It is locked at 175 and returns to normal line pressure control.

In this way, when the tires are locked, the line pressure PL is maintained at a high pressure, and even after recovery, the line pressure PL is maintained in that state until it reaches the high set pressure P'1°. Even when the line pressure is on the high speed stage side, the line pressure is maintained at a high level. Therefore, belt slip due to a delay in the rise of line pressure is also prevented on the secondary pulley 37 side.

The embodiments of the present invention have been described above, but the on-off valve 170
may be provided separately apart from the line pressure regulating valve 90.

〔Effect of the invention〕

As described above, according to the present invention, in the hydraulic control system of a continuously variable transmission, in the case of tire lock during braking on a low μ road, the line pressure is also controlled to a high pressure, so the engine speed increases. There is no delay in the rise of the line pressure when it drops, and belt slip in this case can be reliably prevented.

Furthermore, the line pressure is maintained at a high pressure until the set pressure is reached by downshifting after recovery from tire lock, which is particularly effective in the case of tire lock on the overdrive side.

In addition, an on-off valve is added to the line pressure regulating valve, and the spring force of the on-off valve regulates the line pressure to a high pressure, making it easy to set the line pressure and smooth the transition to normal.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an example of a continuously variable transmission to which the present invention is applied, FIG. 2 is a hydraulic circuit diagram showing an embodiment of the hydraulic control device of the present invention, and FIG. 3 is a configuration diagram of main parts. FIG. 4 is a configuration diagram showing the operating states of the line pressure regulating valve and shift lock mechanism when the tires are locked, and FIG. 5 is a characteristic diagram of each part when the tires are locked.

Claims (3)

[Claims] (1) Hydraulic control that controls the line pressure by having a port where the line pressure regulating valve drains a predetermined amount of line pressure to regulate the pressure, and a balance chamber that acts against the spring force that corresponds to the gear ratio to control the line pressure during normal operation. In the system, an on-off valve is installed in the oil passage of the balance chamber of the line pressure regulating valve so as to introduce or cut off the line pressure and communicate with the drain side, and one of the valve bodies of the on-off valve is equipped with a valve in the event of tire lock. A hydraulic control device for a continuously variable transmission, characterized in that a lock lever that enables switching to the drain side is connected, and a spring is energized on the other side to set the line pressure to a high pressure when switching the tire lock to the drain side. (2) Line pressure is applied to the lock lever side of the valve body of the on-off valve, and when the line pressure rises above the spring set pressure after the tire lock is recovered, the valve body is switched to the line pressure side and the normal line pressure is restored. The hydraulic control device for a continuously variable transmission according to claim 1, wherein the hydraulic control device is configured to return to control. (3) Claim (1) characterized in that the on-off valve is installed between the balance chamber of the line pressure regulating valve and the pressure regulating port.
Hydraulic control device for the continuously variable transmission described.