JPH0826908B2 - Transmission clutch control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a clutch for intermittently controlling power transmission in a transmission, and more particularly to a device for controlling the operation of this clutch.

(Prior Art) There are various types of such clutches depending on the type of transmission, for example, a type using a friction clutch plate in a gear type transmission, and a short circuit in a hydraulic type transmission. There is a clutch valve type that controls the opening degree of the clutch.

For example, Japanese Patent Application Laid-Open
There is a clutch device disclosed in JP-A-56-95722. In this device, a short-circuit passage is formed between two oil passages that connect a hydraulic pump and a hydraulic motor to form a hydraulic closed circuit, and a clutch valve whose opening can be adjusted is arranged in the short-circuit passage. ing. The control device for controlling the operation of the clutch valve has a control force corresponding to the engine rotation for operating the clutch valve in the closing direction (direction to connect the clutch) and the opening direction of the clutch valve (direction to disconnect the clutch).
It is configured to exert a control force corresponding to the throttle opening degree for operating.

In such a clutch device, the opening degree of the clutch valve is usually almost proportional to the operation amount thereof. Here, for example, when the accelerator pedal is suddenly depressed to start the vehicle, the control force for actuating the clutch valve in the opening direction corresponding to the increase in the throttle opening due to the accelerator pedal depression is promptly applied to the control device. In addition, since the increase in engine rotation due to the opening of the throttle valve is slightly delayed, the control force for operating the clutch valve in the closing direction corresponding to the engine rotation is added to the control device with a slight delay. For this reason, the clutch valve is actuated in the opening direction immediately after the accelerator pedal is depressed, and as a result, the engine load is reduced and the engine rotation momentarily becomes unnecessarily high. Moreover, when the engine speed increases,
The control force to operate the clutch valve in the opening direction also becomes high,
At the next moment, the clutch valve is rapidly actuated in the closing direction and the engine speed is reduced. Therefore, there is a problem that hunting of the engine rotation occurs and the starting feeling of the vehicle is impaired.

Further, when the engine is in the idling state, the clutch valve is often closed to some extent and a slight power (creep force) is transmitted (creep state). In this case, if there is a change in the idling rotation, the change in the control force causes a change in the opening of the clutch valve and a change in the engine load, which promotes a change in the idling rotation. Therefore, there is a problem that the idling rotation in the creep state tends to become unstable.

In order to prevent this, it is considered that the change in the opening degree of the clutch valve with respect to the change in the engine rotation should be reduced. However, as described above, the opening degree of the clutch valve is almost proportional to the operation amount of the clutch valve, so that the engine speed change required to completely close the clutch valve becomes considerably large, and the engine speed when the clutch valve is closed becomes too high. There is a problem.

In view of the above, the Japanese Patent Laid-Open No.
Japanese Patent Laid-Open No. 61-207227 discloses a clutch control device in which the opening of the clutch valve is kept constant within a certain range near the valve opening position corresponding to the idling state.

(Problems to be Solved by the Invention) According to the above, when the accelerator pedal is suddenly depressed, even if the clutch valve operates in the opening direction, the opening degree of the clutch valve is kept within a certain range. Keeps idling and avoids unnecessarily increasing engine speed. Further, the clutch valve opening does not change with respect to the engine rotation change in the idling state, and the idling state can be stabilized.

However, in order for the clutch valve to have a constant opening degree only within a predetermined range, there is a problem that the port shape of the clutch valve becomes complicated and machining of the port is extremely difficult.

Therefore, in the present invention, it is possible to use a clutch valve having a port shape that can be formed by ordinary machining, that is, a clutch valve whose opening is substantially proportional to the operation amount, In addition, the engine rotation is swept up (a sudden rise) due to a sudden depression of the accelerator pedal.
It is an object of the present invention to provide a clutch control device having a configuration capable of preventing the occurrence of the occurrence of the above-mentioned phenomenon and obtaining a stable idling state.

B. Configuration of the Invention (Means for Solving the Problems) In order to achieve the above object, in the clutch control device of the present invention, the engine throttle opening is determined based on a signal corresponding to the engine throttle opening and a signal corresponding to the engine rotation. The larger the value, the more the clutch is operated in the releasing direction,
Clutch opening / closing control means for performing clutch opening / closing control so that the clutch operates in the closing direction as the engine speed increases, and corresponds to the engine throttle opening degree to the clutch opening / closing control means when the clutch opening degree is equal to or larger than a predetermined opening degree. And a throttle signal cutoff means for cutting off the signal supply. The clutch opening / closing control means controls the opening / closing of the clutch based on the clutch opening when the clutch opening is equal to or less than a predetermined opening, and increases the rate of decrease of the clutch opening with respect to the change of the engine rotation as the clutch opening becomes smaller. Is configured to.

(Operation) When the operation of the clutch is controlled by the above control device, when the accelerator pedal is depressed, the clutch opening is controlled based on the signals corresponding to the throttle opening and the engine rotation at this time. The clutch is operated in the opening direction, and conversely, the higher the engine speed, the more the clutch is operated in the closing direction. However, when the clutch opening is greater than or equal to the predetermined opening, the throttle opening signal is blocked by the throttle signal blocking means, so only the operation in the clutch closing direction due to the engine rotation is performed, and the clutch is at least less than the predetermined opening. It is always set to the opening.

Here, when the accelerator pedal is suddenly depressed, an increase signal of the throttle opening degree due to the depression of the accelerator pedal is promptly input to the clutch opening / closing control means, and the rise of the engine rotation due to the opening of the throttle is slightly delayed. However, even in this case, the clutch opening does not exceed the predetermined opening, and the engine rotation does not become higher than necessary even if the increase in the engine rotation is delayed. Therefore, the clutch can be smoothly connected even when the accelerator pedal is suddenly depressed.

Further, the clutch opening / closing control means controls the opening / closing of the clutch based on the clutch opening when the clutch opening is equal to or less than a predetermined opening, and increases the rate of decrease of the clutch opening with respect to the change of the engine rotation as the clutch opening becomes smaller. Is configured to. Therefore, when the accelerator pedal is stepped on from the clutch open state to connect it, the clutch opening does not change much with a change in the engine speed immediately after the stepping, the fluctuation of the engine load is suppressed small, and the engine speed becomes excessive. The increase is suppressed.

Even when the engine is idling and creeping, the change in the clutch transmission capacity (change in the clutch valve opening) with respect to the change in engine speed is small, and even if the engine speed changes slightly, the engine load does not change much. Absent. Therefore, the idling state is stable.

(Examples) Hereinafter, preferred examples of the present invention will be described with reference to the drawings.

FIG. 1 is a hydraulic circuit diagram of a continuously variable transmission provided with a clutch control device according to the present invention. In this figure, a continuously variable transmission T is driven by an engine E via an input shaft 1 at a constant discharge. Amount type swash plate axial plunger type hydraulic pump P
And a variable displacement swash plate axial plunger hydraulic motor M that drives wheels (not shown) via the forward / reverse switching device 20. The hydraulic pump P and the hydraulic motor M include a first circuit oil passage La communicating the discharge port of the pump P and the suction port of the motor M with a second circuit oil passage communicating the suction port of the pump P and the discharge port of the motor M. Two oil passages with Lb form a hydraulic closed circuit and are connected. Of the two oil passages La and Lb, the first circuit oil passage La is when the pump P is driven by the engine E and the motor M is rotationally driven by the hydraulic pressure from the pump P to drive the wheels, that is, When the wheels are driven by the engine E via the continuously variable transmission T, the pressure becomes high (the second circuit oil passage Lb is at low pressure at this time), while the second circuit oil passage Lb becomes decelerated during vehicle deceleration. When the engine brake is acted upon by receiving the driving force from the wheels as described above, the pressure becomes high (at this time, the first circuit oil passage La is at low pressure).

A direct coupling clutch valve DC capable of connecting and disconnecting the oil passage La is arranged in the first circuit oil passage La.

A discharge port of a charge pump (supply pump) 10 driven by the engine E through a pair of gear sets 9a and 9b is connected to a regulator valve 12 through a pump discharge oil path Lj. the first control oil passage L ₁ is branched from lj. The regulator valve 12 operates according to the oil pressure of the discharge oil passage Lj, and the discharge oil passage Lj and the first control oil passage L ₁
The hydraulic pressure of the inner set to a predetermined control line pressure P _L, and supplies the control valve or the like which will be described later the hydraulic oil under the line pressure P _L from the first control oil passage L _1.

Oil supply amount to the control valve or the like from the first control oil passage L ₁ is smaller than the discharge amount of the charge pump 10, Therefore,
The remaining oil is sent to the first charge oil passage Lk by the operation of the regulator valve 12. If there is still an excessive amount of oil even after being sent to the first charge oil passage Lk, it is returned from the drain oil passage Lm to the sump 17. Thus, the first charge oil passage
The oil sent to Lk is purified through the centrifugal oil filter 4, and then sent to the third circuit oil path Lc having the pair of check valves 3 and 3 through the second charge oil path Ln. , The check valves 3 and 3 cause the above-mentioned first and second
It is supplied to the low pressure side oil passage of the circuit oil passages La and Lb.

The first lubricating oil passage Ln is connected to the internal space of the motor cylinder 70 forming the pump case from the second charge oil passage Ln.
Lp is branched, and part of the oil supplied to the second charge oil passage Ln is a check valve 6a arranged in the first lubricating oil passage Lp.
And is supplied into the internal space via the oil passage Lp. The oil supplied to the internal space lubricates the pump parts and is sent to the outside from the second lubricating oil passage Lq for lubrication. When the rotation of the motor cylinder 70 is extremely small, that is, when the engine is stopped, the check valve 6b is opened and the hydraulic oil in this internal space is directly pumped.
It is discharged to 17.

A governor valve 8 is mounted coaxially with the charge pump 10. The governor valve 8 is supplied with hydraulic oil of a predetermined pressure from a control valve (not shown), and the governor valve 8 converts the pressure of this hydraulic oil into governor hydraulic pressure corresponding to the rotational speed of the engine E. The input / output oil passage connected to the governor valve 8 will be described later.

A fourth circuit oil passage Ld having a shuttle valve 110 is connected to the closed circuit. This shuttle valve 110 has
The fifth circuit oil passage Le, which has the low-pressure relief valve 7 and is connected to the oil sump 17, is connected. Shuttle valve 110
Operates according to the hydraulic pressure difference between the first and second circuit oil passages La and Lb, and connects the low pressure side oil passage of the first and second circuit oil passages La and Lb to the fifth circuit oil passage Le. . Thereby, the relief hydraulic pressure of the oil passage on the low pressure side is regulated by the low pressure relief valve 7.

A sixth circuit oil passage Lf for short-circuiting both oil passages is also provided between the first and second circuit oil passages La and Lb, and the sixth circuit oil passage Lf controls the degree of opening of the oil passage. A main clutch valve CL including a variable throttle valve is provided.

Further, the seventh circuit oil passage Lg having the engine brake control valve 120 is connected to the first and second circuit oil passages La, Lb.
It is arranged in between.

Further, first and second branched oil passages Lai and Lbi are branched from the first and second circuit oil passages La and Lb, respectively. These two branch oil passages Lai, Lbi are connected to the high-pressure oil passage Lh via check valves 5a, 5b, and are connected to the first and second circuit oil passages La, L.
Hydraulic P _H of the higher one of b is supplied to the high pressure oil passage Lh.

An output shaft 28 is arranged parallel to the rotary shaft 2 of the hydraulic motor M, and a forward / reverse switching device 20 is provided between the shafts 2 and 28.
This device 20 is rotatably supported by an output shaft 28 and is meshed with a first drive gear 21 and first and second drive gears 21 and 22 arranged on the rotary shaft 2 with a space in the axial direction. First to do
Output between the driven gear 23, the second driven gear 25 meshed with the second drive gear 22 via the intermediate gear 24 and rotatably supported by the output shaft 28, and the first and second driven gears 23, 25. Axis 2
A sleeve 27 for selectively connecting the clutch hub 26 fixedly mounted on the shaft 8, and the clutch hub 26 that is slidable in the axial direction and the clutch gear 23a or 25a formed on the side surfaces of the driven gears 23 and 25, respectively. And the sleeve 27 is moved left and right by the shift fork 29. The specific structure of the forward / reverse switching device 20 is shown in FIG. In the forward / reverse switching device 20, the sleeve 27 has a shift fork.
In the state in which the clutch gear 23a of the first driven gear 23 and the clutch hub 26 are slid to the left in the figure by 29 and the clutch hub 23 is connected to the clutch hub 26, the output shaft 28 is rotated in the direction opposite to the rotation shaft 2 and the wheel Is rotated in the forward direction as the continuously variable transmission T is driven. On the other hand, in the state where the sleeve 27 is slid to the right by the shift fork 29 and the clutch gear 25a of the second driven gear 25 and the clutch hub 26 are connected, the output shaft 28 is rotated in the same direction as the rotating shaft 2, The wheels are rotated in the reverse direction.

Next, a specific structure of the continuously variable transmission T will be briefly described with reference to FIG.

The continuously variable transmission T is configured such that a hydraulic pump P and a hydraulic motor M are concentrically arranged in a space surrounded by the first to fourth cases 15a to 15d. The input shaft 1 of the hydraulic pump P is connected to the clutch shaft Es of the engine E via a flywheel 1a. A centrifugal filter 4 is disposed in the inner peripheral recess of the flywheel 1a.

A drive gear 9a is connected to the input shaft 1 by a spline, and a driven gear 9b meshes with the drive gear 9a. The driven gear 9b is coaxially coupled to the drive shaft 11 of the charge pump 10, and the rotation of the engine E is transmitted to the drive shaft 11 of the charge pump 10 via the pair of gears 9a and 9b to drive the charge pump 10. To be done. The drive shaft 11 penetrates the charge pump 10 and projects to the side opposite to the gear 9b, and is also connected to the governor valve 8. Therefore, the rotation of the engine E is also transmitted to the governor valve 8, and the governor valve 8 allows the governor hydraulic pressure corresponding to the rotation of the engine E to be transmitted.
P _G is made.

The hydraulic pump P has a pump cylinder 60 spline-coupled to the input shaft 1 and a plurality of pump runners 62 slidably engaged with a plurality of cylinder holes 61 circumferentially equidistantly formed on the pump cylinder 60. And is rotationally driven by the power of the engine E transmitted through the input shaft 1.

The hydraulic motor M includes a motor cylinder 70 that is provided so as to surround the pump cylinder 60, and a plurality of motor plungers 72 that are slidably fitted into a plurality of cylinder holes 71 that are formed in the motor cylinder 70 at even intervals on the circumference. The pump cylinder 60 is concentric with the pump cylinder 60 and is relatively rotatable.

The motor cylinder 70 is composed of first to fourth portions 70a to 70d which are integrally joined side by side in the axial direction. The first portion 70a is rotatably supported by the case 15b via a bearing 79a on the outer periphery of the left end thereof, and the right inner surface is inclined with respect to the input shaft 1 to form a pump swash plate member. Pump swash plate ring on pump swash plate member
63 are provided. The plurality of cylinder holes 71 are formed in the second portion 70b, and the third portion 70c is formed in each cylinder hole 6.
It has a distribution board 80 in which an oil passage to 1,71 is formed. A gear member having the first and second drive gears 21 and 22 is press-fitted into the fourth portion 70d, and is rotatably supported by the case 15c via a bearing 79b.

An annular pump shoe 64 is rotatably and slidably mounted on the pump swash plate ring 63.
64 and the pump plunger 62 are connected via a connecting rod 65 so as to be swingable to some extent. The pump shoe 64 and the pump cylinder 60 are formed with bevel gears 68a, 68b that mesh with each other. Therefore, when the pump cylinder 60 is rotationally driven from the input shaft 1, the pump shoe 64 is also rotationally driven, and the pump plunger 62 is reciprocated according to the inclination of the pump swash plate ring 63, so that oil is sucked and discharged from the suction port. Oil is discharged to the outlet.

Also, the swash plate member 73 facing each motor plunger 72
Are swingably supported by the second case 15b via a pair of trunnion shafts (swing shafts) 73a projecting from both outer ends thereof in a direction perpendicular to the plane of the drawing. A motor swash plate ring 73b is disposed on a surface of the swash plate member facing the motor plunger 72, and a motor shoe 74 is mounted on the motor swash plate ring 73b in sliding contact therewith. Motorshoe 74
Each motor plunger 72 is swingably connected to the end of the motor plunger 72. The swash plate member 73 is connected to the piston rod 32 of the first shifting servo unit 30 via a ring member 39 at a position away from the trunnion shaft 73a, and the piston rod 32 is linked to the piston rod 32 of the first shifting servo unit 30. When the rod 32 is moved in the axial direction, the swash plate member 73 swings around the trunnion shaft 73a.

The fourth portion 70d of the motor cylinder 70 is formed in a hollow shape, and has a fixed shaft 91 fixed to the pressure distribution plate 18 at the center thereof.
Has been inserted. A distribution ring 92 is liquid-tightly fitted to the left end of the fixed shaft 91, and an axial left end surface of the distribution ring 92 is eccentrically arranged so as to be capable of sliding contact with the distribution plate 80. By this distribution ring 92, a hollow portion formed in the fourth portion 70d is divided into an inner oil chamber and an outer oil chamber, the inner oil chamber forms a first circuit oil passage La, and the outer oil chamber The second circuit oil path Lb is configured. The pressure distribution panel 18 includes a shuttle valve 110,
It has the low pressure relief valve 7 etc., and the third case 15c
And is covered by the fourth case 15d.

A pump discharge port and a pump suction port are bored in the distribution board 80, and a pump plunger in the discharge stroke is provided through the discharge port and the discharge path connected to the pump port.
The cylinder plunger 62 in the suction stroke communicates with a first circuit oil passage La formed of an inner oil chamber, and a pump plunger 62 in a suction stroke through a pump suction port and a suction passage connected thereto.
The second circuit oil passage Lb formed by the cylinder hole 61 and the outer oil chamber communicates with each other. Furthermore, each motor plunger 72
A communication path communicating with the cylinder hole (cylinder chamber) 71 is formed, and the opening of this communication path is formed by the action of the distribution ring 92 in accordance with the rotation of the motor cylinder 70 or the first circuit oil path La or the second It is communicated with the circuit oil passage Lb. Therefore, the cylinder hole 71 of the motor plunger 72 and the first circuit oil passage La in the expansion stroke, and the cylinder hole 71 of the motor plunger 72 and the second circuit oil passage Lb in the contraction stroke are respectively connected via communication paths. Communicated.

In this way, a closed hydraulic circuit is formed between the hydraulic pump P and the hydraulic motor M via the distribution board 80 and the distribution ring 92. Accordingly, when the pump cylinder 60 is driven from the input shaft 1, the high-pressure hydraulic oil generated by the discharge stroke of the pump plunger 62 flows from the pump discharge port to the pump discharge path, the first circuit oil path La (inside oil chamber) and Flows into the cylinder hole 71 of the motor plunger 72 in the expansion stroke through the first communication path which is in communication with the motor plunger 72, and applies a thrust to the motor plunger 72. On the other hand, the hydraulic oil discharged by the motor plunger 72 in the contraction stroke is in the suction stroke via the second communication passage communicating with the second circuit oil passage Lb (outside oil chamber), the pump suction passage and the pump suction port. It flows into the cylinder hole 61 of the pump plunger 62.

Due to such circulation of hydraulic oil, the reaction torque that the pump plunger 62 in the discharge stroke gives to the motor cylinder 70 via the pump swash plate ring 63, and the reaction torque that the motor plunger 72 in the expansion stroke receives from the motor swash plate member 73. Then, the motor cylinder 70 is driven to rotate.

The gear ratio of the motor cylinder 70 to the pump cylinder 60 is given by the following equation.

As can be seen from the above equation, if the swash plate member 73 is swung by the shifting servo unit 30 and the displacement of the hydraulic motor M is changed from 0 to a certain value, the gear ratio is from 1 (minimum value) to a required value ( Maximum value).

On the other hand, as described above, the fourth portion of the motor cylinder 70
A gear member having first and second drive gears is press-fitted and fixed to 70d. Therefore, the rotational driving force of the motor cylinder 70 is transmitted to the output shaft 28 via the forward / reverse switching device 20. The output shaft 28 is connected to a differential device 100 via final gear sets 28a and 28b, and the rotational driving force of the output shaft 28 is transmitted to the differential device 100. Then, the rotational driving force divided by the differential device 100 into the left and right drive shafts 105, 106 is transmitted to the left and right wheels (not shown) to drive the vehicle.

The fixed shaft 9 inserted in the intermediate portion of the fourth portion 70d
A main clutch valve CL that can form a short circuit between the first circuit oil passage La and the second circuit oil passage Lb and that can control the short circuit from fully closed to fully open in 1 and the first circuit oil passage La A direct coupling clutch valve DC capable of intermittent control is provided.

First, the main clutch valve CL will be described. Fixed axis
A short-circuit port that allows the first circuit oil passage La and the second circuit oil passage Lb to communicate with each other is formed in the peripheral wall of 91, and a cylindrical main clutch valve body 95 is provided in the hollow portion of the fixed shaft 91. Has been inserted. The valve body 95 is rotatable relative to the fixed shaft 91, and has a short-circuit hole that can be aligned with the short-circuit port. By rotating the arm 95a formed at the right end of the valve body 95, the valve body 95 is rotated to adjust the amount of alignment (overlap) between the short-circuit port and the short-circuit hole. The size of the matching portion is the opening degree of the short-circuit passage between the first circuit oil passage La and the second circuit oil passage Lb. Therefore, by controlling the rotation of the valve element 95, the opening amount of the short-circuit passage is changed from the fully opened state. It can be controlled until fully closed. If the opening degree of the short-circuit passage is fully open, the hydraulic oil discharged from the pump discharge port to the first circuit oil passage La directly flows into the second circuit oil passage Lb from the short-circuit port and the short-circuit hole and also enters the pump suction port. Since it flows in, the hydraulic motor M is deactivated and the clutch is turned off. On the contrary, if the opening degree of the short-circuit passage is fully closed, the clutch ON state in which the hydraulic motor M operates is realized.

A direct coupling clutch valve DC is arranged in the hollow portion of the main clutch valve body 95. The direct-coupled clutch valve DC includes a piston shaft 85 movably inserted in the valve body 95 in the axial direction.
And a shoe 86 attached to the tip of this piston shaft 85
And the pilot spool 84 inserted in the piston shaft 85
The piston shaft 85 can be moved in the axial direction by following the movement of the pilot spool 84 in the axial direction. Therefore, the pilot spool 84 is moved to the left to
85 is moved to the left, and the shoe 86 at the tip thereof closes the discharge path of the pump opened to the end face of the distribution board 80, so that the first circuit oil path La can be cut off. When the pump discharge path is closed in this way, the pump plunger 62 is hydraulically locked, and the hydraulic pump P and the hydraulic motor M are directly connected.

Next, regarding the control device for the continuously variable transmission T having the above-described configuration,
This will be described with reference to the circuit diagrams of FIGS. 3 and 4.

As the control device, a clutch servo unit 130 for controlling the main clutch CL, a forward / backward servo unit 140 for controlling the operation of the forward / reverse switching device 20, and a swash plate member 7 are provided.
There are first and second servo units 30 and 50 for controlling the gear ratio by oscillating 3, and various controls are performed by appropriately operating these by operating the illustrated hydraulic valves.

Therefore, first, the configuration and operation of each device will be described.

The clutch servo unit 130 includes a fixed cylinder 131,
The piston 131 is slidably fitted in the cylinder 131 in the axial direction, and a spring 133 for urging the piston 132 rightward in the drawing. Left and right cylinder chambers 134 and 135 formed in the cylinder 131 by being divided into two by the piston of the piston member 132 have clutch control valves 2.
Two 6th and 7th control oil passages L ₆ and L ₇ connected to 20 communicate with each other. Therefore, the piston member 132 is moved left and right in the drawing by the hydraulic pressure of the hydraulic oil that is selectively supplied to and discharged from the left and right cylinder chambers 134 and 135 by the clutch control valve 220.

The left end of the piston member 132 is a cam member via a link 96a.
Connected to 97. The cam surface 97a of the cam member 97 is in contact with the end surface of the right spool 223 of the clutch control valve 220, and is fixed at one end to the shaft 98a. A link arm 98b is also fixed to the shaft 98a. The distal end of the link arm 98b is connected via a link 96b to an arm 95a integrally formed with the main clutch valve body 95 described above.
Therefore, when the piston member 132 is moved right and left, the cam member 97 and the link arm 98b are integrally rotated about the shaft 98a, and accordingly, the main clutch valve body 95
Is rotated from the illustrated OFF position (open position) to the ON position (closed position). At this time, the cam surface 97
The a pushes the right spool 223 to the right according to the rotation of the cam member 97.

The clutch control valve 220 includes a left spool 221 and a right spool 223 that are axially movable, and both spools.
It is composed of a spring 222 disposed between 221, 223 and a spring 224 that biases the left spool 221 to the right. Further, in the space in which the spring 224 is disposed (the left space of the left spool 221), the first port communicating with the discharge port of the governor valve 8 is connected.
16 and 17 control oil passage L ₁₇ which communicates via a clutch-on valve 230 to control oil passage L ₁₆ is communicating, this is the left side space governor pressure P _G is supplied that corresponds to the rotational speed of the engine E It Further, in the space where the spring 222 is arranged (the space between the left and right spools 221, 223), the throttle valve 240
The throttle pressure P _TH corresponding to the throttle opening is supplied from the 22nd control oil passage L ₂₂ , the 23rd control oil passage L ₂₃ , the clutch-off valve 235 and the 24th control oil passage L ₂₄ .

Therefore, the left spool 221 is moved to the right or left by the governor pressure P _G and the rightward pressure by the spring 224 and the throttle pressure P _TH and the leftward pressing force by the spring 222.
The line pressure P _L sent from the first control oil passage L ₁ to the fifth control oil passage L ₅ according to this movement is changed to the sixth and seventh control oil passages.
The oil is supplied to one of L ₆ and L ₇ , and the hydraulic oil is discharged to the drain from the other. As a result, the piston member 132 of the clutch servo unit 130 is operated, and the main clutch CL
Is controlled. However, at this time, the piston member 13
The right spool 223 is pressed by the cam member 97 in accordance with the movement of 2, and the pressing force of the spring 222 is changed, so that the opening and closing of the main clutch is performed according to desired characteristics.

Since actuating the ON clutch CL from OFF, when discharging the hydraulic oil in the left cylinder chamber 134 from the sixth control oil passage L ₆ are, eighth, ninth and tenth control from the clutch control valve 220 oil line L _8, is performed via the L _9, L _10. Orifice change valve 27 with the first 10 control oil passage L ₁₀ leads to a drain through the first orifice 274
The orifice 272, 274 limits the discharge speed of the hydraulic oil, and regulates the connection speed (speed from OFF to ON) of the clutch CL.

The connection speed of the clutch CL is required to be faster when the throttle opening of the engine E is small than when it is large. For this reason, the throttle pressure P _TH is introduced from the throttle valve 240 to the right end of the orifice change valve 270 via the 25th control oil passage L ₂₅ , and the throttle opening becomes large and the throttle pressure P _TH becomes higher than a predetermined pressure. The orifice change valve 27
0 is moved to the left so that the valve 270 is closed. In this manner, in the state where the throttle opening is small and the orifice change valve 270 is open, the above-described discharge of the hydraulic oil is performed through the two orifices 272 and 274. When the orifice change valve 270 is closed, the above-described discharge is performed only through one of the orifices 274, and when the throttle opening is large, the connection speed of the main clutch CL becomes slow.

As described above, the discharge speed of the hydraulic oil from the left cylinder chamber 134 of the clutch servo unit 130 is changed according to the throttle opening to adjust the connection speed of the clutch CL to a desired value. However, since this adjustment is performed by the fixed orifices 272, 274, the discharge speed is affected by the change in the viscosity of the hydraulic oil, and, for example, at the time of cold start,
When the operating oil temperature is low, there is a problem that the discharge speed becomes extremely slow, and the connection speed of the clutch CL becomes extremely slow.

In order to solve this problem, in this example, from the 10th control oil passage L ₁₀ to the 11th control oil passage L having the relief valve 260.
₁₁ is branched. This is in consideration of the fact that when the discharge of the hydraulic oil from the fixed orifices 272, 274 is slow at low temperatures, the oil pressure in the oil passage on the upstream side becomes higher than usual. Therefore, the relief valve 260
Indicates that the oil pressure in the oil passage L ₁₁ is at the normal operating temperature (for example, 80 ° C).
It is set to open when the pressure becomes higher than the hydraulic pressure generated at the time of. Therefore, when the hydraulic oil temperature is low, the resistance flowing through the orifices 272, 274 is large, and the oil passage L ₁₁
When the internal oil pressure increases, the relief valve 260 is opened, and even if the amount of oil discharged from the fixed orifices 272, 274 is small, the oil is compensated by the discharge from the relief valve 260, and the connection of the clutch CL is smoothly performed. As a result, even at the time of low-temperature start, the connection of the clutch CL is performed without delay, and the vehicle can be started smoothly.

The forward / backward servo unit 140 includes a fixed cylinder 141,
The piston 141 includes a piston member 142 movably fitted in the cylinder 141 in the axial direction (vertical direction in the figure) and a spring 143 for urging the piston member 142 downward. The space inside the cylinder 141 covered by the cover 146 is divided into two upper and lower cylinder chambers 144 and 145 by the piston of the piston member 142 fitted in this space. 33 Control oil passages L ₃₁ and L ₃₃ are in communication.

Each Ryoaburaro L ₃₁ and L ₃₃ are connected to the manual valve 210 via a direct or clutch-on valve 230 and the 32 control oil passage L _32. Manual valve 210
D, L _2, (D in Fig, 2,1 positions) L ₁ position when in the first 33 control oil with the line pressure P _L from the control oil passage L ₂ to the 31 control oil passage L ₃₁ is supplied When the passage L ₃₃ communicates with the drain and is at the R position, the 33rd control oil passage L
_The line pressure P _L is supplied to ₃₃ and the 31st control oil passage L ₃₁
Is connected to the drain. For this reason, the manual valve 21
When the D, L ₂ , and L ₁ positions are selected by 0, the piston member 142 is moved down as shown in the figure, and the shift fork 29 fixed to the tip of the piston member 142 is located at the forward position.
On the other hand, when the R position is selected, the piston member 142 is moved upward, and the shift fork 29 is located at the reverse position. At positions other than this, that is, at the N and P positions, both control oil passages L ₃₁ and L are
Both ₃₃ are communicated with the drain. In this case, the biasing force of the spring 143 holds the piston member 142 in the down position and the shift fork 29 in the forward position.

Further, when the piston member 142 the line pressure P _L to the upper cylinder chamber 144 is supplied is moved downwardly, the line pressure P _L through the circumferential groove 142a of the piston member 142 is introduced into the 15 control oil path L ₁₅ When the line pressure P _L is supplied to the lower cylinder chamber 145 and the piston member 142 is moved upward, the line pressure P _L is set to the first pressure through the through hole 142b in the piston member 142.
5 Introduced into control oil passage L ₁₅ .

Next, the shift servo units 30, 50 shown in FIG. 4 will be described. Both units 30 and 50 are connected via a link mechanism 40.

The first shifting servo unit 30 includes a fixed cylinder 31 and
A piston rod 32 movably fitted in the cylinder 31 upward in the drawing, a valve member 33 fixedly held in the rod 32, and a valve member 33 movably inserted vertically in the valve member 33. And a spool member 34. The internal space of the cylinder 31 is covered by a cover (not shown) in the upper part of the figure, and is divided into two by a piston portion 32a of a piston rod 32 to form upper and lower cylinder chambers 35 and 36. Further, the lower end of the piston rod 32 projects to the outside of the cylinder 31, and is connected to the swash plate member 73 of the motor M via a link member 39 as shown in FIG.

The cylinder 31 has a high-pressure oil passage Lh connected thereto and a high-pressure introduction hole 31a for communicating the high-pressure oil passage Lh with the lower cylinder chamber 36. The lower cylinder chamber 36 has a high-pressure side in the hydraulic closed circuit of the transmission T in the lower cylinder chamber 36. hydraulic oil is introduced having a hydraulic P _H. Hydraulic oil under the high pressure P _H further spool within the valve member 33 via the communication hole 33b from the groove 33a with guided in a groove 33a of the valve member 33 via the communication hole 32b of the piston rod 32 It is led to a member insertion hole (not shown).

When the spool member 34 inserted into this insertion hole is moved relative to the valve member 33 in the upper direction in the drawing, the spool member 34 closes the communication hole 33b of the valve member 33, and moves the upper cylinder chamber 35 into the piston rod 32. When it is discharged to the drain through the through hole 32c and is relatively moved downward, the valve member 33
The communication hole 33b communicates with the upper cylinder chamber 35. Therefore, when the spool member 34 is moved upward, the piston rod 32 follows the spool member 34 and is moved upward by the hydraulic pressure of the high pressure P _H acting on the lower cylinder chamber 36. Further, when moved downward spool member 34, a high pressure P _H is applied to the upper and lower cylinder chambers 35, 36 by the difference in pressure receiving area of the piston portion 32a (the larger pressure receiving area of the upper cylinder chamber 35 side) The piston rod 32 is moved down following the spool member. When the spool member 34 is stationary, the piston rod 32 is also held stationary at a position where the forces applied to the piston portion 32a from the upper and lower cylinder chambers 35 and 36 are balanced. That is, when the spool member 34 is moved up and down, the piston rod 32 is moved up and down following this. At this time, since the piston rod 32 is connected to the swash plate member 73 of the motor M, the movement of the spool member 34 can control the swash plate angle, that is, control the speed ratio of the transmission T.

The upper end of the spool member 34 is connected to one end of the second link 42 via the first link 41. The second link 42 is integrally connected to the shaft 43 and is rotatable around the shaft 43. A third link 44 is also integrally connected to the shaft 43, and a third link
44 is a second speed change servo unit 50 via a fourth link 45
Of the piston member 52. Therefore, when the piston member 52 is moved up and down in the figure, the links 41-
The spool member 34 of the first speed-change servo unit 30 is moved up and down via a link mechanism 40 constituted by 45.

The second shift servo unit 50 is configured such that the piston member 52 is fitted into a fixed cylinder 51 so as to be movable in the axial direction (vertical direction in the figure). Fixed cylinder 51
The internal space is covered by the plug member 53, and is divided into two by the piston portion of the piston member 52 to form upper and lower cylinder chambers 54, 55. In the upper cylinder chamber 54,
Through 42 control oil passage L ₄₂ is communicated via a second 45 control oil passage L ₄₅ having a first 44 control oil passage L ₄₄ and a check valve 57b having an orifice 57a, the 40 control oil passage in the lower cylinder chamber 55 L ₄₀ is in communication. 42 control oil passage L ₄₂ is a clutch-off valve 235
And through a second 41 control oil passage L _41, also the 40 control oil passage L ₄₀
Communicates with the shift control valve 250 as it is.

Therefore, by the action of the shift control valve 250, the line pressure P _L from the fifteenth control oil passage L ₁₅ is supplied to the upper cylinder chamber 54 and the lower cylinder chamber 55, or the working oil in the cylinder chamber is discharged. Supply of such hydraulic oil
The piston member 52 is moved up and down in response to the discharge, and this is transmitted to the first shift servo unit 30 via the link mechanism 40 to perform shift control. Specifically, the piston ratio 52 is increased (shifted to the LOW side) by moving the piston member 52 of the second speed changing servo unit 50 upward and moving the piston member 32 of the first speed changing servo unit 30 downward. On the contrary, by operating the piston member 52 to move the piston member 32 upward, the gear ratio can be reduced (shifted to the TOP side).

In this case, the supply of the line pressure P _L to the upper cylinder chamber 54 is gradually made by the action of the orifice 57a, the discharge of hydraulic fluid from the upper cylinder chamber 54 the check valve 57b is made rapidly opened. For this reason, when the gear ratio is increased by moving the piston member 52 upward (when shifting to the LOW side), this is performed rapidly, but the piston member 52
When the gear ratio is decreased by lowering (shifting to the TOP side), this is done gently. However, the piston member 52 and the first groove 52a is formed in the vicinity of the piston unit (piston member 52 when the 43 control oil passage L ₄₃ which communicates with the hole formed in the cylinder 51, a large gear ratio The upper cylinder chamber 54 communicates with the upper cylinder chamber 54 through this groove (when the upper part moves upward by a predetermined amount or more). Therefore, the line pressure P _L is supplied through the 43rd control oil passage L ₄₃ until the piston member moves downward by a predetermined amount or more and becomes equal to or lower than a certain value, and a rapid speed change is performed during this period. It

The lower end of the piston member 52 is formed with a tapered surface 52d, and the end surface of the spool 151 of the throttle cam mechanism 150 is in contact with the tapered surface 52d. It is configured so that it can operate.

Further, through holes 56a, 56b connected to the insertion holes of the piston member 52 are formed in the upper part of the cylinder 51, and the 46th and 47th control oil passages L ₄₆ , L ₄₇ are respectively communicated with the through holes 56a, 56b. To do. Grooves 52b and 52c are formed in the upper part of the piston member 52 to allow the through holes 56a and 56b to communicate with the drain when the piston member 52 is moved upward by a predetermined amount or more. For this reason, when the piston member 52 is moved upward and the gear ratio decreases (approaches the TOP side), first,
47 control oil path L ₄₇ is communicated with the drain through the groove 52c and the through hole 56b, further piston member 52 is moved upward, the groove
46 control oil passage L ₄₆ is communicated with the drain via 52b and hole 56a.

Hereinafter, each valve shown in FIGS. 3 and 4 will be briefly described.

The spool 211 of the manual valve 210 is operated in response to a shift lever operation in the driver's seat, and the operation of the forward / backward traveling servo unit 140 is controlled as described above. When the spool 211 is located at the “2” position (L ₂ position), the 48th control oil passage L ₄₈ having the governor pressure is provided.
The when communicated to the 46 control oil passage L _46, located at "1" position (L ₁ position) is a 48th control oil passage L ₄₈ 4
7 to communicate with the control oil passage L _47. For this reason, when the spool 211 is in the “2” or “1” position, when the speed ratio falls below a predetermined value, the governor pressure in the _forty- eighth control oil passage L ₄₈ is drained, and the shift control is performed as described later. Valve 25
The governor pressure acting on 0 becomes zero and the gear ratio is prevented from becoming smaller (to the TOP side).

Normally, the clutch-on valve 230 is in a state where the spool 231 is moved leftward as shown in the drawing by the pressing force of the spring 232. However, when the controller 100 detects that the vehicle speed becomes equal to or higher than the predetermined vehicle speed, the normally open type first solenoid valve 280 is actuated and closed, and the third control oil passage L ₅₁ is provided with the third control oil passage. Line pressure P _L from line L ₃ is generated, and this hydraulic pressure causes spool 232
Is moved to the right. Thus, to the 17 control oil passage L ₁₇ is the line pressure P _L from the 34 control oil passage L ₃₄ is supplied, the left spool 221 of the clutch control valve 220 is shifted rightward, the main clutch CL is how the state Irrespective of the ON state (connected state). At the same time, the line pressure P _L is supplied to the engine brake control valve 120 shown from the 60 control oil passage L ₆₀ in Figure 1. Note that this time, before the 33 control oil passage L ₃₃ leading to the lower cylinder chamber 144 of the reverse servo unit 140 communicates with the drain, the manual valve 210 during running in this state is switched to the reverse (R) In addition, the safety is improved by preventing the servo unit 140 from operating.

The clutch-off valve 235 has a manual valve 210 of N,
In the cases other than the P position, the spool 236 is moved to the left as shown by the line pressure P _L from the fifteenth control oil passage L ₁₅ acting on the right end of the spool 236 and the manual valve 210.
Is switched to the N (or P) position, it is moved to the right by the spring 237. When the spool 236 is moved to the right,
The line pressure P _L from the fourth control oil passage L ₄ is supplied to the 24th control oil passage L ₂₄ , the left spool 221 of the clutch control valve 220 is moved to the left, and the main clutch CL is turned off.
At the same time, the 42nd control oil passage L ₄₂ is closed, the piston member 52 of the second shifting servo unit 50 is held as it is, and the gear ratio is held as it is.

The throttle modulator valve 245 is connected to the 20th control oil passage L.
_The line pressure P _L supplied to ₂₀ is reduced to generate a predetermined modulator pressure P _M , which is supplied to the throttle valve 240 via the 21st control oil passage L ₂₁ .

The throttle valve 240 is actuated in response to the pressing of the first cam 161 of the throttle cam mechanism 150 which is actuated in response to the accelerator pedal or the throttle valve opening,
The throttle pressure P _TH corresponding to the throttle opening (or accelerator opening) is supplied to the control oil passage L ₂₂ .

The shift control valve 250 of the spool 251 receives the pressing force of the second cam 171 of the throttle cam mechanism 150 transmitted via the spring 252 and the pressing force of the governor pressure P _G from the 49th control oil passage L ₄₉ . This is a valve that controls the supply and discharge of the line pressure P _L to the upper and lower cylinder chambers 54, 55 of the second speed changing servo unit 50 by moving left and right. Thus, the gear ratio is controlled according to the throttle opening (or depression of the accelerator pedal) and the engine speed.

Kick down control valve 258, when the accelerator pedal is depressed rapidly during running is the valve to increase the speed change ratio was drained hydraulic oil from the 42 control oil passage L ₄₂ (toward LOW) .

Engine inhibitor valve 265 is actuated when the governor pressure P _G engine becomes a predetermined rotational or a predetermined or more, with a valve to shut off the first 48 control oil passage L ₄₈ communication between the first 49 control oil passage L ₄₉ .

The second solenoid valve 285 is a normally closed type valve, and is opened when the controller 100 detects a sudden braking operation. For this reason, normally, the line pressure P
_L is supplied, but this is released at the time of sudden braking, and the spool 2 of the shift control valve 250
51 is moved to the right, and the gear ratio is controlled to be on the LOW side.

The operation control of the main clutch CL by the clutch servo unit 130 and the clutch control valve 220 in the transmission T having the control device configured as described above will be described in detail below.

The main clutch CL variably controls the matching amount between the short-circuit port and the short-circuit hole (this becomes the opening area of the clutch) by rotating the valve body 95. As shown in FIG. 5, the relationship between the rotation angle (clutch angle) and the opening area is such that when the clutch angle is 0 degree (when the valve body 95 is in the OFF position in FIG. 3), the opening area is maximum. And at 80 degrees (ON
Position) is zero.

The clutch angle is set by the supply and discharge of hydraulic oil from the clutch control valve 220 to the left and right cylinder chambers 134 and 135 of the clutch servo unit 130.
It is controlled by the pressing force balance to 221. This pressing force
As described above, the governor pressure P _G acting rightward (this corresponds to engine rotation), the pressing force of the spring 224, and the throttle pressure P _TH acting leftward (this corresponds to the throttle opening). And the pressing force of the spring 222. For this reason,
As shown in FIG. 6, the clutch angle is determined by the engine speed Ne.
(Rpm). In this figure, each line A, B, C has the throttle opening fully closed,
The characteristics in the case of half open and full open are shown.

As shown in this figure, each line A, B, C is not a straight line,
It is parabolic, and the change rate of the clutch angle with respect to the change of the engine rotation is larger as the clutch angle is larger. That is, when the clutch angle is small, the clutch angle does not change much even when the engine rotation changes, but when the clutch angle increases, the clutch angle changes largely with respect to the engine rotation change. This is because when the piston member 132 of the clutch servo unit 130 is moved to the left to increase the clutch angle, the pressing of the right spool 223 by the cam member 97 is increased, and the spring 222 pushes the left spool 221 to the left. This is because the pushing force increases as the clutch angle increases.

If such a characteristic setting is made, for example, when the throttle is almost fully closed (the characteristic of the line A), the change in the clutch angle is small with respect to the change in the engine speed in the engine idling state (point a ₁ ). Become. Therefore, even if the idling rotation fluctuates, the clutch angle fluctuates (that is,
Clutch valve opening fluctuation) is small, engine load fluctuation does not occur much, and the idling state is stable.

It should be noted that the conventional characteristic in which there is no pressing by the cam member 97 is shown by the one-dot chain line A '. In this case, the clutch angle greatly changes with respect to the engine speed fluctuation in the idling state (point a ₁ ), and the idling state Is prone to instability. If the characteristic setting such as the chain double-dashed line A ″ that makes the rate of change of the clutch angle with respect to the engine speed fluctuation in the idling state (point a ₁ ) similar to the case of the characteristic A is performed, the idling state can be stabilized. the case, the clutch from becoming fully closed, is when shown at point a _3, is too high engine speed at this time.

Also, as can be seen from FIG. 6, the clutch opening is about 25.
Only the above is set. In the case where the shift range is the traveling range, the clutch is closed to this angle (25 degrees) so that the creep force is transmitted from the engine to the wheels. This point will be described.

Two concave portions 223a and 223b are formed on the outer periphery of the right spool 223 of the clutch control valve 220. The recesses 223a, respectively, the 25 control oil passage L ₂₅ connected to the 12 control oil passage L ₁₂ and 23 control oil passage L ₂₃ branched from the eighth control oil passage L ₈ is communicated to 223b. Further, both of these recesses are open to the outside at the right end of the recess when the main clutch angle is zero, and this opening causes the piston member 132 of the clutch servo unit 130 to move to the left and the cam member.
97, the value decreases as the right spool 223 moves leftward, and becomes zero when the piston member 132 moves leftward until the clutch angle becomes approximately 25 degrees.

Since the 12 control oil passage L ₁₂ communicating with the recess 223a is connected to the eighth control oil passage L _8, when the recess 223a is communicated with the outside it is discharged to the eighth control oil passage L ₈ Hydraulic oil from the left cylinder chamber 134 is rapidly discharged through the recess 223a. On the other hand, the 25th control oil passage L communicating with the recess 223b.
_25, the manual valve 210 running range when the (R, D, 2 or 1 range) is selected, the 23 control oil passage L _23, the clutch-off valve 235 and the 24 control oil passage L
Via ₂₄ , it communicates with the space between the left and right spools 221 and 223 of the clutch control valve 220. In the case of the neutral range (P or N range), the 23 control oil passage L ₂₃ by the clutch-off valve 235 is closed.

Here, by operating the shift lever, the manual valve 21
Consider a case where 0 is switched from the neutral range (P or N range) to the traveling range (R or D range). No. 15 control oil passage in case of neutral range
Since the oil pressure in L ₁₅ is zero, the spool 236 of the clutch-off valve 235 is moving to the right due to the bias of the spring 237, and the 24th control oil passage L exists in the space between the left and right spools 231 and 233 of the clutch control valve 220. _The line pressure P _L is supplied from the fourth control oil passage L ₄ via ₂₄ . Therefore, the left spool 221 is shifted leftward, hydraulic oil under the line pressure P _L to the left cylinder chamber 134 of the clutch servo unit 130 from the fourth control oil passage L ₄ through a sixth control oil passage L ₆ is The piston member 132 is completely moved rightward, and the clutch angle is zero, that is, the main clutch CL is OFF.

From this state, is switched to the running range by the manual valve 210, the line pressure to the 15 control oil path L ₁₅ P _L
Is supplied, and the spool 236 of the clutch-off valve 235 is moved left as shown. Therefore, the space between the left and right spools 221 and 223 of the clutch control valve 220 is
Control oil passage L _24, via a clutch-off valve 235 and the 25 control oil passage L _25, communicating with the recess 223b.

Immediately after this switching, the main clutch CL is OFF, the right spool 223 is moved to the right as described above, and the recess 223b is opened to the outside. For this reason, the hydraulic pressure in the space between the left and right spools 221 and 223 becomes zero, and the left spool 221
There is the line pressure P _L to the right cylinder chamber 135 of the clutch servo unit 130 is supplied shifted leftward, the piston member 132 is shifted leftward. As a result, the clutch angle is increased and the main clutch CL is operated in the ON direction, but the left movement of the piston member 132 is until the recess 223b is closed, that is, the clutch angle is in the creep state of about 25 degrees. Done. When the recess 223b is open, the recess 22
3a is also open, so that the piston member 132
Of the hydraulic oil in the left cylinder chamber 134 when moved to the left from the sixth control oil passage L ₆ 8 and 12 control oil passage L _8, L ₁₂ and recess
Drained through 223a. Therefore, the piston member 13
The left movement of 2 is made rapidly.

Thus, in the case of this example, the manual valve 210
Is switched from the neutral range to the travel range, the clutch is rapidly moved from the fully open position (the position where the clutch angle is zero) to the creep position (the position where the clutch angle is approximately 25 degrees).

After moving to the creep position, both recesses 223
Since a and 223b are closed, the clutch control valve
220 operates according to the engine rotation and throttle opening, and the main clutch CL is controlled to open and close along a characteristic curve as shown in FIG.

In this case, let us consider a case where the accelerator pedal is suddenly depressed from the idling state a ₁ to start the vehicle or the like. At this time, as described above, the increase in the engine speed is slightly delayed, whereas the throttle opening immediately increases and the throttle pressure P _TH moves the left spool 221 of the clutch control valve 220 to the left to open the clutch valve. It operates to reduce the clutch angle. However, when the clutch angle is further reduced from the idling state a _1, the hydraulic oil having the throttle pressure P _TH that acts to move the left spool 221 to the left as described above is drained through the 25th control oil passage L _25. Therefore, the clutch valve will not open any more. Therefore, an appropriate engine load is maintained, a sudden increase in engine rotation and the occurrence of hunting accompanying it are prevented, and a smooth clutch connection is achieved.

In this way, it is possible to effectively suppress hunting of engine rotation or the like due to a sudden depression of the accelerator pedal, but without draining by the recesses 223a and 223b formed in the right spool 223 as described above, By merely setting the characteristics of the parabolic lines A, B, and C as shown in FIG. 6, the above-mentioned hunting can be prevented to some extent.

For example, consider a case where the accelerator pedal is suddenly depressed from the idling state shown by the point a ₁ and the throttle opening becomes half open (state of line B). Immediately after this depression, the engine rotation remains idling rotation N ₁ , so
In the case of the characteristic according to the present invention, the clutch angle is about to be opened up to the opening degree (about 12 degrees) of the point b ₁ corresponding to this rotation N ₁ in the extended portion of the line B shown by the broken line. On the other hand, in the case of the conventional characteristic shown by the one-dot chain line B ', the opening corresponding to idling rotation is a negative value, and the valve is about to be opened to the full opening (opening 0 degree). Thus, the characteristics of the present invention (lines A, B,
In the case of the characteristic indicated by C), the opening amount of the clutch valve with respect to the depression of the accelerator pedal can be suppressed to be small. Therefore, an excessive increase in engine rotation is suppressed, and hunting is less likely to occur.

In the above, the example of controlling the clutch valve of the hydraulic continuously variable transmission has been shown, but the present invention is not limited to this. For example, the same applies to the case of controlling a friction plate type clutch by a servo unit. Is.

C. As described above, according to the present invention, when the clutch opening degree is equal to or larger than the predetermined opening degree, the throttle signal cutoff means for cutting off the signal supply corresponding to the engine throttle opening degree to the clutch opening / closing control means is provided. ing. Therefore, when the accelerator pedal is depressed, the clutch opening is controlled based on the signal corresponding to the throttle opening and the engine rotation at this time, and the larger the throttle opening, the more the clutch is operated in the opening direction, and vice versa. Is higher, the clutch is operated in the closing direction. However, when the clutch opening is greater than or equal to the predetermined opening, the throttle opening signal is blocked by the throttle signal blocking means, so only the operation in the clutch closing direction due to the engine rotation is performed, and the clutch is at least less than the predetermined opening. It is always set to the opening.

Here, when the accelerator pedal is suddenly depressed, an increase signal of the throttle opening degree due to the depression of the accelerator pedal is promptly input to the clutch opening / closing control means, and the rise of the engine rotation due to the opening of the throttle is slightly delayed. However, even in this case, the clutch opening does not exceed the predetermined opening, and the engine rotation does not become higher than necessary even if the increase in the engine rotation is delayed. Therefore, the clutch can be smoothly connected even when the accelerator pedal is suddenly depressed.

Further, the clutch opening / closing control means controls the opening / closing of the clutch based on the clutch opening when the clutch opening is equal to or less than a predetermined opening, and increases the rate of decrease of the clutch opening with respect to the change of the engine rotation as the clutch opening becomes smaller. Is configured to. For this reason, when the accelerator pedal is depressed from the clutch opening response to connect it, the clutch opening does not change much with respect to changes in the engine speed immediately after the depression, and fluctuations in the engine load are suppressed to a small extent, resulting in excessive engine rotation. The increase is suppressed.

Further, in the case of a creep condition due to engine idling, the change in the clutch opening degree with respect to the change in the engine speed is small, and even if the engine speed slightly changes, the engine load does not change much. Therefore, the idling state can be stabilized.

[Brief description of drawings]

FIG. 1 is a hydraulic circuit diagram of a continuously variable transmission provided with a clutch control device according to the present invention, FIG. 2 is a cross-sectional view of the continuously variable transmission, and FIGS. 3 and 4 are diagrams of the continuously variable transmission. FIG. 5 is a control circuit diagram, FIG. 5 is a graph showing the opening area of the clutch valve with respect to the clutch angle, and FIG. 6 is a graph showing the relationship between the clutch angle and the engine speed and the throttle opening. 1 ... Input shaft, 8 ... Governor valve 10 ... Charge pump, 20 ... Forward / reverse switching device 30,50 ... Shifting servo unit 95 ... Clutch valve disc, 97 ... Cam member 110 ... Shuttle valve 130 …… Clutch servo unit 140 …… Forward / reverse servo unit 210 …… Manual valve 220 …… Clutch control valve 272,274 …… Orifice change valve 260 …… Relief valve

Claims (2)

[Claims] 1. A clutch that disconnects power transmission between input and output shafts of a transmission and a signal corresponding to an engine throttle opening and a signal corresponding to engine rotation, the greater the engine throttle opening, the more the clutch is engaged. Operate in the opening direction,
A clutch opening / closing control unit that controls opening / closing of the clutch so that the clutch operates in a closing direction as the engine speed increases, and the engine to the clutch opening / closing control unit when the clutch opening degree is a predetermined opening degree or more. The clutch opening / closing control means is configured to cut off the signal supply corresponding to the throttle opening, and the clutch opening / closing control means controls the opening / closing of the clutch based on the clutch opening when the clutch opening is less than or equal to a predetermined opening. A clutch control device for a transmission, wherein a reduction rate of the clutch opening degree with respect to a change in the engine speed is increased as the clutch opening degree decreases. 2. The clutch is configured to be opened / closed by a hydraulic servo unit, and the clutch opening / closing control means is configured to open / close the hydraulic pressure based on a signal corresponding to an engine throttle opening and a signal corresponding to engine rotation. The clutch control device for a transmission according to claim 1, comprising a hydraulic valve that controls the supply of hydraulic oil to the servo unit.