JPH02159470A - Clutch control device for transmission - Google Patents

Abstract

PURPOSE:To prevent a sudden increase in engine speed by controlling the increase rate of power transmission capacity during an engine speed rise from the first predetermined level to the second predetermined level in such a way as to raise the rate according to the increase of operation transmission capacity. CONSTITUTION:When an acceleration pedal is stepped down, power transmission capacity or the opening of a clutch valve CL is determined by the throttle opening of an engine E and the rotation thereof. Furthermore, the clutch valve CL gradually closes according to an engine speed increase and the transmission capacity of a continuously variable transmission T gradually increases. In this case, the change of clutch transmission capacity for the engine speed increase is small when the capacity is small, while the change is large when the capacity is large. When the acceleration pedal is stepped for connecting a clutch from the open condition thereof, the clutch transmission capacity does not change so much for an engine speed change immediately after the stepping of the pedal, thereby enabling the restraining of an engine load fluctuation to a low level. According to the aforesaid construction, it is possible to prevent a rapid engine speed rise in the sudden stepping of the acceleration pedal and the like.

Description

DETAILED DESCRIPTION OF THE INVENTION OBJECTS OF THE INVENTION (Field of Industrial Application) The present invention relates to a clutch for controlling power transmission on and off in a transmission, and more particularly to a device for controlling the operation of this clutch.

(Prior Art) There are various types of such latch depending on the type of transmission, such as a type using a friction clutch plate in a gear type transmission, and a type using a short circuit type in a hydraulic transmission. There are clutch valve types that control the opening of the valve.

For hydraulic transmissions, for example, Japanese Patent Application Laid-open No. 5
There is a clutch device disclosed in Japanese Patent No. 6-95722. In this device, a short-circuit path is formed between two oil paths that connect a hydraulic pump and a hydraulic motor to form a hydraulic closed circuit, and a clutch valve that can adjust the opening degree of the short-circuit path is arranged. ing. The control device that controls the operation of this clutch valve has a control force corresponding to engine rotation to operate the clutch valve in the closing direction (to connect the clutch), and a control force corresponding to the engine rotation to operate the clutch valve in the opening direction (to disengage the clutch). The controller is configured to exert a control force corresponding to the throttle opening to operate the throttle valve.

In such a latch device, the opening degree of the clutch valve is usually approximately proportional to its operating amount. Here, for example, when the accelerator pedal is suddenly depressed to start the vehicle, the control force that operates the clutch valve in the opening direction corresponding to the increase in throttle opening due to the depression of the accelerator pedal is immediately transferred to the control device. However, since there is a slight delay in the increase in engine rotation as the throttle valve opens, the control force that operates the clutch valve in the closing direction corresponding to the engine rotation is applied to the control device with a slight delay. For this reason, the clutch valve is operated in the valve opening direction immediately after the accelerator pedal is depressed, and as a result, the engine load is reduced and the engine rotation momentarily becomes higher than necessary. Moreover, as the engine speed increases, the control force for operating the clutch valve in the closing direction also increases, and at the next instant, the clutch valve is rapidly operated in the closing direction and the engine speed decreases. For this reason, there is a problem in that engine rotation hunting occurs and the starting feeling of the vehicle is impaired.

Further, when the engine is in an idling state, the clutch valve is often closed to some extent to transmit a small amount of power (creep force) (creep state).

In this case, if there is a change in the idling rotation, the resulting change in the control force will cause the clutch valve opening degree to vary and the engine load to fluctuate, which will aggravate the idling rotation change.

For this reason, there is a problem in that idling rotation in a 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 engine rotation should be made smaller. However, as mentioned above, the clutch valve opening is almost proportional to its operating amount, so the change in engine rotation required to completely close the clutch valve is quite large, and the engine rotation when the clutch valve is closed becomes too high. There is a problem.

In view of this, the applicant proposed that
Japanese Patent No. 1-207227 discloses a clutch control device that maintains the opening degree of a clutch valve constant within a certain range near a valve opening position corresponding to an idling state.

(Problem to be Solved by the Invention) With the above method, even if the clutch valve operates in the opening direction when the accelerator pedal is suddenly depressed, the opening degree will be limited within a certain range. The engine is kept idling to avoid increasing the engine speed more than necessary. Furthermore, the clutch valve opening does not change in response to changes in engine rotation during idling, making it possible to stabilize the idling state.

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

For this reason, in the present invention, it is possible to use a clutch valve having a port shape made by ordinary machining, that is, a clutch valve whose opening degree is almost proportional to the amount of operation. Another object of the present invention is to provide a clutch control device configured to prevent engine rotation from rising rapidly due to sudden depression of the accelerator pedal, etc., and to provide a stable idling state. shall be.

B6 Structure of the Invention (Means for Solving the Problems) To achieve the above object, in the clutch control device of the present invention, when the index corresponding to the engine throttle opening is constant, the engine rotation is When the engine speed is below a predetermined speed, the power transmission capacity of the clutch is set below a predetermined value, and as the engine speed increases from the first predetermined speed to a second predetermined speed higher than this, the power transmission capacity is maximized. Further, when the engine speed increases from the first predetermined rotation speed to the second predetermined rotation speed, the increase rate of the power transmission capacity with respect to the engine rotation is set such that the larger the power transmission capacity is, the higher the power transmission capacity is. I'm trying to get bigger.

(Function) If the clutch operation is controlled by the above control device, when the accelerator pedal is depressed, the power transmission capacity, that is, the clutch opening is determined from the throttle opening and engine rotation at this time, and as the engine rotation increases, the clutch opening is determined. The transmission capacity of the lever is gradually increased (the clutch opening is gradually closed) and the clutch is engaged. In this case, the change in clutch transmission capacity (rate of change in clutch opening in the closing direction) with respect to the increase in engine speed is small when clutch transmission capacity is small (when the clutch valve is open), and small when it is large (when the clutch valve is open). ) is large when the valve is closed. For this reason,
When you press the accelerator pedal from the clutch open state to connect it, the clutch transmission capacity (clutch valve opening) does not change much in response to changes in engine speed immediately after the clutch is pressed down, and engine load fluctuations are suppressed to a minimum, resulting in a change in engine speed. can be prevented from increasing excessively.

In addition, even when the engine is idling and in a creep state, the change in clutch transmission capacity (change in clutch valve opening) in response to changes in engine speed is small, and even if the engine speed changes slightly, the engine load does not change much. do not have. Therefore, the idling state becomes stable.

(Embodiments) Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

FIG. 1 is a hydraulic circuit diagram of a continuously variable transmission equipped with a clutch control device according to the present invention. A volume type swash plate axial plunger type hydraulic pump P,
A variable capacity swash plate axial plunger type hydraulic motor M that drives wheels (not shown) via a forward/reverse switching device 20
It has These hydraulic pump P and hydraulic motor M have a first circuit oil passage La that communicates the discharge port of the pump P and the suction port of the motor M, and a second circuit oil passage La that communicates the suction port of the pump P and the discharge port of the motor M. The two oil passages with Lb constitute a hydraulic closed circuit and are connected to each other. Of these two oil passages La and Lb, the first circuit oil passage La is used when the pump P is driven by the engine E and the motor M is rotationally driven by the oil pressure from the pump P to drive the wheels. Continuously variable transmission T with engine E
When the wheels are driven through the vehicle, the pressure becomes high (at this time, the second circuit oil path Lb is at low pressure), while the second circuit oil path Lb receives driving force from the wheels, such as when the vehicle is decelerating. In response to this, the pressure becomes high when the engine brake is applied (at this time, the pressure in the first circuit oil passage La is low).

A direct coupling clutch valve DC that can connect and disconnect the oil passage La is disposed within the first circuit oil passage La.

Engine E via a pair of gear sets 9a + 9b
The discharge port of the charge pump (replenishment pump) 10 driven by the pump is connected to the regulator valve 12 via a pump discharge oil passage Lj, and a first control oil passage L1 branches from this discharge oil passage Lj. ing. The regulator valve 12 operates according to the oil pressure in the discharge oil path Lj, sets the oil pressure in the discharge oil path Lj and the first control oil path to a predetermined control line pressure PL, and controls the line pressure PL. The hydraulic oil is supplied from the first control oil passage L"1 to a control valve, etc., which will be described later.

The amount of oil supplied from this first control oil path to the control valves, etc. is small compared to the discharge amount of the charge pump 10, so the remaining oil is supplied to the first control oil path by the operation of the regulator valve 12.
It is sent to charge oil path Lk. In addition, when there is still an excess amount of oil even after sending it to the first charge oil path Lk, it is returned to the sump 17 from the drain oil path Lm. In this way the first
The oil sent to the charge oil path Lk is purified through the centrifugal oil filter 4, and then passes through the second charge oil path Ln to the third circuit oil path La having a pair of check valves 3.3. By the action of the check valves 3, 3, the oil is supplied to the lower pressure side of the first and second circuit oil passages La, Lb.

Note that a first lubricating oil passage Lp that connects to the internal space of the motor cylinder 70 that constitutes the pump case branches from the second charge oil passage Ln, and a portion of the oil supplied to the second charging oil passage Ln is The oil passes through a check valve 6a disposed in the first lubricating oil passage Lp and is supplied into the internal space via this oil passage Lp. The oil supplied to this internal space lubricates the pump parts and is sent to the outside from the second lubricating oil path LQ for lubrication. Note that 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 discharged into the sump 17.

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

A fourth circuit oil path La having a shuttle valve 110 is connected to the closed circuit. A fifth circuit oil passage La having a low pressure relief valve 7 and connected to the oil sump 17 is connected to the shuttle valve 110. The shuttle valve 110 operates according to the oil pressure difference between the first and second circuit oil passages La, Lb, and operates between the first and second circuit oil passages La, Lb.
b, the low pressure side oil passage is communicated with the fifth circuit oil passage La. As a result, the relief oil pressure in the oil passage on the low pressure side is regulated by the low pressure relief valve 7.

A sixth circuit oil passage Lf that short-circuits both oil passages is also provided between the first and second circuit oil passages L a + L b. A main clutch valve CL consisting of a variable throttle valve is provided to control the main clutch valve CL.

Further, the second circuit oil passage 1g having the engine brake control valve 120 is connected to the first and second circuit oil passages t,
It is arranged between a, L, and b.

Moreover, the first and second circuit oil passages 1. , a, and Lb branch into first and second circuit oil passages 1 at and L bl, respectively. These two branch oil passages L at , L bl
is connected to the high pressure oil path Lhi via check valves 5a and 5b, and the first and second circuit oil paths L a +L
The higher oil pressure PH among the oil pressures b is supplied to this high pressure oil path Lh.

An output shaft 28 is arranged parallel to the rotating shaft 2 of the hydraulic motor M, and a forward/reverse switching device 20 is provided between both shafts 2 and 28. This device 20 includes first and second drive gears 21 and 22 disposed on a rotating shaft 2 with a spacing in the axial direction, and rotatably supported by an output shaft 28 and a first drive gear 2
1, a second wave gear 25 that meshes with the second drive gear 22 via an intermediate gear 24 and is rotatably supported on the output shaft 28, and the first and second wave gears. 23. A clutch hub 26 is fixed to the output shaft 28 between 25 and 25, and a clutch gear 23a or 25a, which is slidable in the axial direction and is formed between the clutch hub 26 and the side surfaces of the driven gears 23 and 25, respectively, is selected. This sleeve 27
is moved left and right by the shift fork 29. In addition,
The specific structure of this forward/reverse switching device 20 is shown in FIG.

In this forward/reverse switching device 20, when the sleeve 27 is slid leftward in the drawing by the shift fork 29 and the clutch gear 23a of the first wave gear 23 and the clutch hub 26 are connected as shown in the drawing, the output is The shaft 28 is rotated in the opposite direction to the rotating shaft 2, and the wheels are rotated in the forward direction as the continuously variable transmission T is driven. On the other hand, the sleeve 27 is slid to the right by the shift fork 29 and the second driven gear 2
When the clutch gear 25a of No. 5 and the clutch hub 26 are connected, the output shaft 28 is rotated in the same direction as the rotating shaft 2, and the wheels are rotated in the reverse direction.

Next, the concrete structure of the continuously variable transmission T will be briefly explained using FIG. 2.

This continuously variable transmission T has first to fourth cases 15a to 15d.
A hydraulic pump P and a hydraulic motor M are arranged intermittently in a space surrounded by. An input shaft 1 of the hydraulic pump P is coupled to a crankshaft E'S of an engine E via a flywheel 1a. A centrifugal filter 4 is disposed within a recess on the inner peripheral side of the flywheel 1a.

Further, 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 connected 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+9b, thereby driving the charge pump 10. . This drive shaft 11 passes through the charge pump 10 and protrudes 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 this governor valve 8, and the governor valve 8 causes the engine E to rotate.
Governor hydraulic pressure P corresponding to the rotation of. is made.

The hydraulic pump P includes a pump cylinder 60 spline-coupled to the input shaft 1, and a plurality of pump plungers 62 slidably engaged with a plurality of cylinder holes 61 formed in the pump cylinder 60 at equal intervals on the circumference. It 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 provided by dividing the pump cylinder 60 by %I]II, and a motor cylinder 70.
It is composed of a plurality of motor plungers 72 that are slidably engaged with a plurality of cylinder holes 71 formed at equal intervals on the circumference, and can rotate relative to the pump cylinder 60 coaxially.

The motor cylinder 70 is composed of first to fourth parts 70a to 70d that are aligned in the axial direction and are integrally coupled.

The first portion 70a has a bearing 7 at its left end outer periphery.
The pump swash plate ring 63 is rotatably supported by the case 15b via the pump 9a, and the right inner surface is inclined with respect to the input shaft 1 to form a pump swash plate member. is provided. The plurality of cylinder holes 71 are formed in the second portion 7°b, and the third portion 70c has a distribution plate 80 in which oil passages to each cylinder hole 61, 71 are formed. A gear member having the first and second drive gears 21 and 22 is press-fitted into the fourth portion 70d, and is connected to the case 1 through a bearing 79b.
It is rotatably supported by 5c.

An annular pump shoe 64 is rotatably and slidably attached to the pump swash plate ring 63, and the pump shoe 64 and the pump plunger 62 are connected to each other via a connecting rod 65 so as to be able to swing freely to some extent. . The pump shoe 64 and the pump cylinder 60 have a bevel gear E that meshes with each other.
38a and 68b are formed. Therefore, input shaft 1
When the pump cylinder 60 is rotationally driven, the pump shoe 64 is also rotated at the same time, and the pump plunger 62 is reciprocated according to the inclination of the pump swash plate ring 63, sucking oil from the suction port and discharging oil from the discharge port. will be done.

Also, a swash plate member 73 facing each motor plunger 72
However, the second case 15
It is swingably supported by b. A motor swash plate ring 73b is disposed on the 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 by a sliding fluid. The motor shoe 74 is swingably connected to the end of each motor plunger 72. This swash plate member 73 is connected to the piston rod 32 of the first shift servo unit 30 via a link member 39 at a position away from the trunnion shaft 73a.
When the piston rod 32 is moved in the axial direction,
The swash plate member 73 is configured to swing around a trunnion shaft 73a.

The fourth portion 70d of the motor cylinder 70 is formed hollow, and a fixed shaft 91 fixed to the pressure distribution board 18 is inserted into the center thereof. A distribution ring 92 is fluid-tightly fitted to the left end of the fixed shaft 91, and the left end surface of the distribution ring 92 in the axial direction is eccentric so that it can come into sliding contact with the distribution plate 80.

This distribution ring 92 divides the hollow portion formed within the fourth portion 70d into an inner oil chamber and an outer oil chamber, with the inner oil chamber forming the first circuit oil passage La and the outer oil chamber forming the first circuit oil passage La. A second circuit oil path Lb is configured. Note that the pressure distribution panel 18 includes shuttle valves 110. It has a low pressure relief valve 7, etc.
Attached to the right side of the third case 15C,
It is covered by a fourth case 15d.

A pump discharge port and a pump suction boat are bored in the distribution board 80, and the cylinder hole 61 of the pump plunger 62 in the discharge stroke and the inner oil chamber are connected through the discharge port and the discharge passage connected thereto. The second circuit oil passage Lb, which is made up of the cylinder hole 61 of the pump plunger 62 in the suction stroke and the outer oil chamber, is communicated with the first circuit oil passage La, and via the pump suction boat and the suction passage connected thereto. communicated. Furthermore, a communication path communicating with the cylinder hole (cylinder chamber) 71 of each motor plunger 72 is formed in the distribution board 80, and the opening of this communication path is
Due to the action of the distribution ring 92, it is communicated with the first circuit oil passage La or the second circuit oil passage Lb according to the rotation of the motor cylinder 70. Therefore, the cylinder hole 71 of the motor plunger 72 in the expansion stroke and the first circuit oil passage La are different from the cylinder hole 71 of the motor plunger 72 in the contraction stroke and the second circuit oil passage La.
The circuit oil passages Lb are communicated with each other via communication passages.

In this way, a hydraulic closed circuit is formed between the hydraulic pump P and the hydraulic motor M via the distribution panel 80 and the distribution ring 92. Therefore, when the pump cylinder 60 is driven from the input shaft 1, high-pressure hydraulic oil generated by the discharge stroke of the pump plunger 62 is transferred from the pump discharge boat to the pump discharge passage, the first circuit oil passage La (inner oil chamber), and the like. It flows into the cylinder hole 71 of the motor plunger 72 which is in the expansion stroke through the first communication path which is in communication with the
A thrust is applied 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 path communicating with the second circuit oil path Lb (outer oil chamber), the pump suction path, and the pump suction boat. It flows into the cylinder hole 61 of the pump plunger 62.

Due to this circulation of hydraulic oil, the reaction torque that the pump plunger 62 in the discharge stroke applies 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. The motor cylinder 70 is rotationally driven by the sum of .

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 oscillated by the gear shifting servo unit 30 and the capacity of the hydraulic motor M is changed from O to a certain value, the gear ratio can be changed from 1 (minimum value) to a certain required value. (maximum value).

On the other hand, as described above, a gear member having first and second drive gears is press-fitted and fixed into the fourth portion 70d of the motor cylinder 70. For this reason, the motor cylinder 70
The rotational driving force is transmitted to the output shaft 2 via the forward/reverse switching device 20.
8.

This output shaft 28 is connected to a differential device 100 via a final gear set 28a, 28b.
The rotational driving force of the output shaft 28 is provided by the differential device 10.
0. And the differential device 10
The rotational driving force divided by the left and right drive shafts 105 and 10E3 by the rotational power is transmitted to the left and right wheels (not shown) to drive the vehicle.

A short-circuit path between the first circuit oil passage La and the second circuit oil passage Lb is formed in the fixed shaft 91 inserted into the hollow portion of the fourth portion 70d, and this short-circuit path can be changed from fully closed to fully opened. A main clutch valve CL that can control up to 100 degrees, and a direct clutch valve DC that can control the first circuit oil passage La on and off are provided.

First, the main clutch valve CL will be explained. A first circuit oil passage La and a second circuit oil passage Lb are provided on the peripheral wall of the fixed shaft 91.
A cylindrical main clutch valve body 95 is inserted into the hollow portion of the fixed shaft 91. 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 an arm 95a formed at the right end of the valve body 95, the valve body 95 can be rotated to adjust the amount of alignment (overlapping) between the short circuit port and the short circuit hole. The size of this matching part becomes the opening degree of the short-circuit passage between the first circuit oil passage La and the second circuit oil passage Lb, and therefore, by controlling the rotation of the valve body 95, the opening degree of the short-circuit passage is changed from fully open to fully open. It can be controlled up to full throttle. If the short circuit passage is fully open, the first
The hydraulic oil discharged into the circuit oil passage La flows directly from the short circuit boat and the short circuit hole into the second circuit oil passage Lb and also flows into the pump suction boat, so the hydraulic motor M becomes inactive and the clutch is in the OFF state. Become. Naturally, on the contrary, if the opening degree of the short-circuit passage is fully closed, a clutch ON state in which the hydraulic motor M operates is realized.

A direct coupling clutch valve DC is disposed within the hollow portion of this main clutch valve body 95. This direct-coupled Clara valve DC includes a piston shaft 85 pushed into the valve body 95 so as to be movable in the axial direction, a shoe 86 attached to the tip of the piston shaft 85, and a pilot inserted into the piston shaft 85. A pilot spool 84
By moving in the axial direction, the piston shaft 85 can be moved in the axial direction to follow this movement. Therefore, the pilot spool 84 is moved to the left, the piston shaft 85 is moved to the left, and the shoe 86 at the tip of the pilot spool 84 is moved to the left to block the discharge path of the pump that opens to the end face of the distribution board 80, thereby blocking the first circuit oil path La. It is now possible to do so. In this state where the pump discharge passage is closed, the pump plunger 62 is hydraulically locked, and the hydraulic pump P and the hydraulic motor M are directly connected.

Next, the control device for the continuously variable transmission T having the above configuration will be explained using the circuit diagrams shown in FIGS. 3 and 4.

The control device includes a clutch servo unit 130 that controls the main clutch CL, a forward/reverse servo unit 140 that controls the operation of the forward/reverse switching device 20, and a swash plate member 73 that swings to control the seven gear ratios. First thing to do
and a second shift servo unit) 30.50, which are operated as appropriate by the operation of the hydraulic valve shown in the figure.
Various controls are performed.

First, the configuration and operation of each device will be explained.

The clutch servo unit 130 has a fixed cylinder 131
The piston member 132 is fitted into the cylinder 131 so as to be slidable in the axial direction, and a spring 133 biases the piston member 132 to the right in the figure. The cylinder 13 is divided into two parts by the piston of the piston member 132.
In the left and right cylinder chambers 134, 135 formed in 1,
Two sixths connected to Crabchi control valve 220
and seventh control oil passage L8. L7 is in communication with each other. Therefore, the piston member 132 is moved from side to side in the figure by the hydraulic pressure of the hydraulic oil selectively supplied to and discharged from the left and right cylinder chambers 134, 135 by the Crabchi control valve 220.

The left end of the piston member 132 is connected to a cam member 97 via a link 96a. The cam member 97 has its cam surface 97
a is the right spool 2 of the clutch control valve 220
23, and one end is fixed to the shaft 98a. A link arm 98b is also fixed to the shaft 98a. The tip of this link arm 98b is a link 98
It is connected to an arm 95a integrally formed with the main clutch valve body 95 described above through b. Therefore, when the piston member 132 is moved left and right, the cam member 97 and the link arm 98b are rotated together around the shaft 98a, and the main clutch valve body 95 is accordingly moved to the OFF position shown in the figure. (open position) to ON position (closed position)
It is rotated between. Note that at this time, the cam surface 97a
is adapted to push the right spool 223 to the right in response 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 movable in the axial direction, and a spring 222 disposed between the spools 221 and 223.
The spring 224 biases the left spool 221 to the right. Furthermore, the space in which this spring 224 is arranged (
In the left side space of the left spool 221, there is a governor valve 8.
The 17th control oil passage L communicates with the 16th control oil passage L1e through the clutch-on valve 230 and communicates with the discharge port of
17 is in communication with the governor pressure P.17 corresponding to the rotation speed of the engine E in this left side space. is supplied. In addition, the space where the spring 222 is arranged (the left and right spools 221
, 223) contains a throttle valve 240.
Throttle pressure Pru corresponding to the throttle opening is transmitted from
is supplied.

Therefore, the left spool 221 is connected to the governor pressure P0 and the spring 2
It is moved to the right or to the left in response to a rightward pushing force by 24 and a leftward pushing force by throttle pressure PTH and spring 222. In response to this movement, the line pressure PL sent from the first control oil path to the fifth control oil path L5 is supplied to one of the sixth and seventh control oil paths LII, L7, and the other is activated. Drain the oil to the drain. As a result, the piston member 132 of the clutch servo unit 130
is operated, and the operation of the main clutch CL is controlled. However, at this time, the right spool 223 is pushed by the cam member 97 in accordance with the movement of the piston member 132, and the spring 22
The pushing force of 2 can be changed, so that the main clutch can be opened and closed according to desired characteristics.

In addition, when discharging the hydraulic oil in the left cylinder chamber 134 from the sixth control oil passage L8 in order to operate the clutch CL from OFF to ON, the clutch control valve 22
0 to 8th, 9th and 10th control oil passages L s r L
e + L, done via a. This 10th control oil passage L+o is connected to the drain via the first orifice 274 and also to the drain via the orifice change valve 270 and the second orifice 272, and these orifices 272, 274 control the discharge rate of the hydraulic oil. is limited, and the connection speed (speed from OFF to ON) of clutch CL is adjusted.

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 PT□ is introduced from the throttle valve 240 to the right end of the orifice change valve 270 via the second and fifth control oil passages L25, and the throttle opening becomes larger and the throttle pressure P
When TH becomes a predetermined pressure or higher, the orifice change valve 270 is moved to the left by this hydraulic pressure, and this valve 27
0 is closed. In this way, the throttle opening is small and the orifice change valve 27
When 0 is open, the above-mentioned hydraulic oil discharge is 2
However, when the throttle opening is large and the orifice change valve 270 is closed, the discharge is performed only through one of the orifices 274. In this case, the connection speed of the main clutch CL becomes slow.

As described above, the discharge speed of hydraulic oil from the left cylinder chamber 134 of the clutch servo unit 130 is changed in accordance with the throttle opening degree, and the connection speed of the clutch CL is adjusted to a desired value.

However, since this adjustment is performed using fixed orifices 272 and 274, the discharge speed is affected by changes in the viscosity of the hydraulic oil. There is a problem in that the connection speed of the clutch CL becomes extremely slow.

In order to solve this problem, in this example, an eleventh control oil passage L□□ having a relief valve 260 is branched from the tenth control oil passage L+o. This is done in consideration of the fact that when the discharge of hydraulic oil from the fixed orifices 272 and 274 is slow at low temperatures, the oil pressure in the oil passage upstream from these becomes higher than normal. Therefore, the relief valve 260 is set to open when the oil pressure in the oil passage L11 becomes higher than the oil pressure generated at the normal operating temperature (for example, 80''C).

Therefore, the orifice is 272°274° when the hydraulic oil temperature is low.
When the flow resistance is large and the oil pressure in the oil passage L11 is high, this relief valve 280 is opened, and even if the amount of oil discharged from the fixed orifices 272, 274 is small, it is compensated for by the discharge from the relief valve 260, To smoothly connect a clutch CL. This allows the clutch CL to be connected without delay even when starting at a low temperature, making it possible to start the vehicle smoothly.

The servo unit 140 for forward and backward movement has a fixed cylinder 141
The piston member 142 is fitted into the cylinder 141 so as to be movable in the axial direction (up and down in the figure), and a spring 143 urges the piston member 142 downward. The space inside the cylinder 141 covered by the cover 146 is
The piston of the piston member 142 fitted into this space divides the space into an upper and a lower cylinder chamber 1'44, 145, and both cylinder chambers 144, 145 have a 31st and 33rd control oil passage L311L, respectively. 3jll
are communicating.

Both logic paths L31 and Laa are each connected to the manual valve 210 directly or via the clutch-on valve 230 and the 32nd control oil path L32. Manual valve 210, L2. When the L1 position is in the 2.1 position (in the figure), the line pressure PL from the control oil passage L2 is supplied to the 31st control oil passage L31, and the 33rd control oil passage L3G is connected to the drain. When in communication and in the R position, line pressure Pt is supplied to the 33rd control oil passage L0, and the 31st control oil passage L3
1 is connected to the drain. For this reason, the manual valve 210 allows L2. When L-posisilon is selected, the piston member 142 is moved downward as shown, 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 in the reverse position. In addition, other positrons, that is, N
In the and P position, both control oil passages L3□
and L33 are both connected to the drain,
In this case, the piston member 1 is biased by the spring 143.
42 is held at the lower movement position, and the shift fork 29 is placed at the forward position.

Furthermore, when the line pressure Pt is supplied to the upper cylinder chamber 144 and the piston member 142 is moved downward, this line pressure PL is introduced into the fifteenth control oil passage L16 via the outer circumferential groove 142a of the piston member 142, When the line pressure PL is supplied to the lower cylinder chamber 145 and the piston member 142 is moved upward, the through hole 1 in the piston member 142
42b, this line pressure PL is applied to the 15th control oil passage L1.
5 will be introduced.

Next, the shift servo units 30 and 50 shown in FIG. 4 will be explained. Both units) 30.50 is link mechanism 4
Connected via 0.

The first speed change servo unit 30 includes a fixed cylinder 31, a piston rod 32 fitted into the cylinder 31 so as to be movable up and down in the figure, a valve member 33 fixedly held within the rod 32, and The spool member 34 is inserted into the valve member 33 so as to be movable up and down in the figure. The internal space of the cylinder 31 is covered at the upper part of the figure by a cover (not shown), and is divided into two parts by the piston portion 32a of the piston rod 32 to form upper and lower cylinder chambers 35 and 38. Also,
The lower end of the piston rod 32 projects outward from the cylinder 31, and is connected to a swash plate member 73 of the motor M via a link member 39, as shown in FIG.

A high pressure oil passage Lh is connected to the cylinder 31, and a high pressure introduction hole 31a that communicates this with the lower cylinder chamber 36
is formed, and hydraulic oil having a hydraulic pressure PH on the high pressure side in the hydraulic closed circuit of the transmission T is introduced into the lower cylinder chamber 38. The hydraulic oil having this high pressure P)I is further guided to the groove 33a of the valve member 33 via the communication hole 32b of the piston rod 32, and is also guided into the groove 33a of the valve member 33 from this groove 33a via the communication hole 33b. It is guided into a spool member insertion hole (not shown).

When the spool member 34 inserted into this insertion hole is moved upward relative to the valve member 33 in the figure, it closes the communication hole 33b of the valve member 33 and opens the upper cylinder chamber 35 inside the piston rod 32. When it is discharged to the drain through the through hole 32c and is relatively moved downward,
The communication hole 33b of the valve member 33 is communicated with the upper cylinder chamber 35. For this reason, the spool member 3
4, the high pressure P acting on the lower cylinder chamber 36 increases.
The piston rod 32 is moved to the spool member 3 by the hydraulic pressure of H.
It will be moved up following 4. Also, when the spool member 34 is moved downward, high pressure P is applied to the upper and lower cylinder chambers 35 and 36.
I+ is added, and the difference in pressure receiving area at the piston portion 32a (
(the pressure receiving area on the upper cylinder chamber 35 side is larger), the piston rod 32 is moved downward following the spool member. Note that 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, 36 are balanced. That is, when the spool member 34 is moved up and down,
The piston rod 32 follows this and is moved up and down. At this time, the piston rod 32 is connected to the swash plate member 73 of the motor M.
Since the spool member 34 is moved, the swash plate angle can be controlled, that is, the gear ratio of the transmission T can be controlled.

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

The second speed change servo unit 50 is constructed by fitting the piston member 52 into a fixed cylinder 51 so as to be movable in the axial direction (in the vertical direction in the figure). The internal space of the fixed cylinder 51 is covered by the plug member 53 and divided into two by the piston portion of the piston member 52 to form upper and lower cylinder chambers 54 and 55. The upper cylinder chamber 54 includes a 44th control oil passage L 44 having an orifice 57a and a 4th control oil passage L 44 having a check valve 57b.
A 42nd control oil passage L4□ communicates with the lower cylinder chamber 55 via the 5 control oil passage L4fl, and a 40th control oil passage L40 communicates with the lower cylinder chamber 55. The 42nd control oil passage L4° is connected via the clutch off valve 235 and the 41st control oil passage L41.
The 0 control oil passage L 40 directly communicates with the shift control valve 250 .

Therefore, due to the action of the shift control valve 250, the upper cylinder chamber 54 and the lower cylinder chamber 55 are
Line pressure Pt from control oil path L15.

is supplied or the hydraulic oil in the cylinder chamber is discharged. The piston member 52 is moved up and down in response to the supply and discharge of hydraulic oil, and this is transmitted to the first gearshift servo unit 30 via the link mechanism 40 to perform gearshift control. Specifically, the piston member 52 of the second shift servo unit 50 is moved upward to move the first shift servo unit).
By moving the piston member 32 of 30 downward, the gear ratio is increased (shifted to the LOW side).
By moving the piston member 52 downward and the piston member 32 upward, the gear ratio is reduced (shifted to the TOP side).
can be done.

In this case, the line pressure Pt is gradually supplied to the upper cylinder chamber 54 by the action of the orifice 57a, but the hydraulic oil is discharged from the upper cylinder chamber 54 by the check valve 5.
7b is opened and done rapidly. Therefore, when moving the piston member 52 upward to increase the gear ratio (LOW
This is done rapidly when shifting to the side), but when the piston member 52 is moved downward to reduce the gear ratio (
When shifting to the TOP side), this is done slowly. However, the piston member 52 has a first
A groove 52a is formed, and the 43rd control oil passage L43 communicating with the hole formed in the cylinder 51 passes through this groove when the gear ratio is large (when the piston member 52 is moving upward by a predetermined amount or more). It communicates with the upper cylinder chamber 54 through the upper cylinder chamber 54. Therefore, the line pressure Pt is supplied through the 43rd control oil passage L41 until the piston member moves downward by a predetermined amount or more and the gear ratio falls below a certain value, and during this period, a rapid speed change is performed.

Note that 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 this tapered surface 52d.
The throttle cam mechanism 150 is configured to operate in accordance with the gear ratio.

Furthermore, through holes 56a and 58b are formed in the upper part of the cylinder 51, and the through holes 56a and 58b are connected to the insertion hole of the piston member 52.
Control oil path L4!11L4□ is in communication.

Grooves 52b and 5'2c are formed in the upper part of the piston member 52 to connect the through holes 58a and 56b to the drain when the piston member 52 is moved upward by a predetermined amount or more. Therefore, the piston member 52 is moved upward, and the gear ratio becomes smaller (TO
When the piston member 52 is moved upward, the 47th control oil passage L47 is first communicated with the drain via the groove 52C and the through hole 56b. The 46th control oil passage L411 is communicated with the drain.

Each valve illustrated in FIGS. 3 and 4 will be briefly described below.

The spool 211 of the manual valve 210 is operated in response to the shift/L/bar operation from the driver's seat, and the operation of the forward/reverse servo unit 140 is controlled as described above. Note that when the spool 211 is located at the "2" position (L2 position), the fourth
8 control oil passage Laa is communicated with the 46th control oil passage L4B,
When the spool 211 is in the '1' position (L, position), the 48th control oil passage L4a is communicated with the 47th control oil passage L47. Therefore, when the spool 211 is in the '2' or '1' position, When the gear ratio falls below a predetermined value, the governor pressure in the 48th control oil passage L4Q is drained, and as will be described later, the governor pressure acting on the shift control valve 250 becomes zero, and the gear ratio becomes smaller than this.
(to the TOP side) is prevented.

The clutch-on valve 230 is normally connected to its spool 23.
1 has been moved to the left by the pushing force of the spring 232 as shown in the figure. However, the controller 100
When it is detected that the vehicle speed has become equal to or higher than a predetermined vehicle speed, the normally open type first solenoid valve 280 is operated and closed, and a line from the third control oil passage L3 is inserted into the 51st control oil passage LISw. A pressure Pt is generated, and the spool 232 is moved to the right by this hydraulic pressure. As a result, the line pressure PL from the 34th control oil passage L34 is supplied to the 17th control oil passage L17, and the clutch control valve 22
0's left spool 221 is moved to the right, and the main clutch C
L is kept in the ON state (connected state) regardless of its state. At the same time, line pressure P is also supplied from the 60th control oil passage L8° to the engine brake control valve 120 shown in FIG. Note that at this time, the third cylinder connected to the lower cylinder chamber 144 of the forward/reverse servo unit 140
3 control oil passage L 33 communicates with the drain, and even if the manual valve 210 is switched to reverse (R) while the vehicle is running in this state, this servo unit 140 is prevented from operating to improve safety. There is.

Clutch off valve 235 is manual valve 210
In cases other than those in N and P positions, spool 2
36 is moved to the left as shown in the figure by the line pressure PL from the 15th control oil passage L15 acting on its right end, and when the manual valve 210 is switched to the N (or P) position, it is moved to the right by the spring 237. Ru. When the spool 236 is moved to the right, the fourth
Line pressure PL is supplied from control oil path L4, left spool 221 of clutch control valve 220 is moved to the left, and main clutch CL is turned off. at the same time,
The 42nd control oil passage L4□ is closed, the piston member 52 of the second speed change servo unit 50 is held as it is, and the speed change ratio is held as it is.

The throttle modulator valve 245 reduces the line pressure PL supplied to the 20th control oil passage L20 to create a predetermined modulator pressure PH, and supplies this to the throttle valve 240 via the 21st control oil passage L21. .

The throttle valve 240 is operated in response to the suppression of the first cam 161 of the throttle cam mechanism 150, which is operated in response to the accelerator pedal or the throttle valve opening, and the throttle opening (or the accelerator A throttle pressure PTH corresponding to the opening degree) is supplied.

The shift control valve 250 is connected to the second cam 17 of the throttle cam mechanism 150 through a spring 252.
1 and the governor pressure P from the 49th control oil passage L48.
. This valve controls the supply and discharge of the Lyso pressure Pt to the upper and lower cylinder chambers 54 and 55 of the second shift servo unit 50 by the left and right movement of the spool 251 which receives the pressing force from the servo unit 50. As a result, the gear ratio is controlled according to the throttle opening (or the depression of the accelerator pedal) and the engine speed.

The kickdown control valve 258 widens the gear ratio by discharging hydraulic oil from the 42nd control oil passage L4Q when the accelerator pedal is suddenly depressed while driving.
This is a valve for switching to the LOW side.

The engine rotation inhibitor valve 265 operates at governor pressure P when the engine rotation exceeds a predetermined rotation. is activated when the value exceeds a predetermined value, and the 48th control oil passage L48 and the 49th control oil passage L
This is a valve that cuts off communication with 49.

The second solenoid valve 285 is a normally closed type valve, and is opened when the controller 100 detects sudden braking. For this reason, line pressure PL is normally supplied to the right end of the shift control valve 250, but in the event of sudden braking, this is released, the spool 251 of the shift control valve 250 is moved to the right, and the gear ratio is shifted to the LOW side. controlled so that

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 amount of alignment between the shorting port and the shorting hole (this becomes the opening area of the clutch) by rotating the valve body 95. The relationship between this rotation angle (clutch angle) and the opening area is as shown in FIG. 5 when the clutch angle is 0 degrees (when the valve body 95 is
When the opening area is at F position), the opening area is maximum, and when it is 80 degrees - (at the ON position), it is zero.

The clutch angle is determined from the clutch control valve 220 to the left and right cylinder chambers 134 of the clutch servo unit 190.
．． It is set by supplying and discharging hydraulic oil to the left spool 221, and this supply and discharge is controlled by the balance of the pushing force to the left spool 221.

As mentioned above, this pushing force is caused by the governor pressure Pa (which corresponds to the engine rotation) acting in the right direction and the spring 22
4 and the throttle pressure PT□ that acts in the left direction.
(This corresponds to the throttle opening) and the pushing force by the spring 222. Therefore, as shown in FIG. 8, the clutch angle can be expressed in correspondence to the engine rotational speed Ne (rpm). In addition, in this figure, each line A, B, C
show the characteristics when the throttle opening is fully open, half open, and fully open, respectively.

As shown in this figure, each of the lines A, B, and C is not a straight line but a parabola, and the larger the clutch angle, the larger the rate of change of the clutch angle with respect to the change in engine rotation. That is, when the clutch angle is small, the clutch angle does not change much even if the engine rotation changes, but when the clutch angle becomes large, the clutch angle changes greatly in response to changes in the engine rotation. 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 right spool 223 is strongly suppressed by the cam member 97, and the leftward direction from the spring 222 to the left spool 221 is increased. This is because the pushing force increases as the clutch angle increases.

If such characteristics are set, for example, when the throttle is almost fully open (in the case of the characteristic of line A), the change in the clutch angle will be small with respect to the change in engine rotation in the engine idling state (point at). . Therefore, even if there is a fluctuation in idling rotation, the clutch angle will fluctuate (i.e.,
(fluctuations in clutch valve opening degree) are small, engine load fluctuations do not occur much, and idling conditions are stable.

Note that the conventional characteristic without suppression by the cam member 97 is shown by a dashed line A', but in this case, the change in clutch angle with respect to engine rotation fluctuations in the idling state (point a) is large, and tends to become unstable. The idling state can be stabilized by setting the characteristic as indicated by the chain double-dashed line A#, which makes the rate of change of the clutch angle with respect to engine speed fluctuations in the idling state (point a+) the same as in the case of characteristic A. However, the clutch is fully opened at point a3, and the engine speed at this time becomes too high.

Also, as can be seen from Figure 6, the clutch opening degree is approximately 25
It can only be set to a value higher than 100 degrees. this is,
When the shift range is the travel range, the clutch is closed to this angle (25 degrees) to create a creep state in which creep force is transmitted from the engine to the wheels, and this point will be explained below.

Right spool 223 of clutch control valve 220
Two recesses 223a and 223b are formed on the outer periphery of. These recesses 223a and 223b each have
The 25th control oil passage L2 is connected to the 12th control oil passage Ll□ branched from the 8th control oil passage L8 and the 23rd control oil passage L23.
5 are connected.

Furthermore, both of these concave portions are opened to the outside at their right end portions when the main clutch angle is zero, and this opening occurs when the piston member 132 of the clutch servo unit 130 moves to the left and the right spool 223 is moved by the cam member θ7.
decreases as it moves to the left, and becomes zero when the piston member 132 moves to the left until the clutch angle reaches about 25 degrees.

Since the twelfth control oil passage L1□ communicating with the recess 223a is connected to the eighth control oil passage L8, this recess 223a
is in communication with the outside, the hydraulic oil from the left cylinder chamber 134 discharged into the eighth control oil passage L8 flows through this recess 2.
It is rapidly discharged via 23a. On the other hand, the recess 223b
The 25th control oil passage L25, which communicates with
is selected, it communicates with the space between the left and right spools 221, 223 of the clutch control valve 0 via the 23rd control oil passage L2G, the clutch off valve 235, and the 24th control oil passage L24. Note that in the case of the neutral range (P or N range), the clutch off valve 235 closes the 23rd control oil passage L23.

Here, the manual valve 21 is opened by operating the shift lever.
Let us consider a case where the vehicle is driven from a neutral range (P or N range) and is switched to range (R or D range). In the case of the neutral range, since the oil pressure in the 15th control oil passage L15 is zero, the clutch off valve 2
The spool 236 of No. 35 is moved to the right by the bias of a spring 237, and the space between the left and right spools 231 and 233 of the clutch control valve 220 has a 24th control oil passage L2.
Line pressure PL is supplied from the fourth control oil passage L4 via line L4. Therefore, the left spool 221 is moved to the left, and the line pressure P flows from the fourth control oil passage L4 through the sixth control oil passage L8 into the left cylinder chamber 134 of the clutch servo unit 130.
t is supplied, the piston member 132 moves completely to the right, and the clutch angle is zero, that is, the main clutch CL is in an OFF state.

When the manual valve 210 switches to the driving range from this state, the line pressure PL is supplied to the 15th control oil passage L15, and the spool 236 of the clutch off valve 235 is moved to the left as shown. For this reason, the left and right spools 221, 2 of the clutch control valve 220
The space between 23 is connected via the 24th control oil passage L24, the clutch off valve 235, and the 25th control oil passage L25,
It communicates 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. Therefore, the oil pressure in the space between the left and right spools 221 and 223 becomes zero, and the left spool 221 is moved to the left to supply line pressure Pt to the right cylinder chamber 135 of the clutch servo unit 130, and the piston member 132 is moved to the left. As a result, the clutch angle increases and the main clutch CL is operated in the ON direction, but the leftward movement of the piston member 132 remains until the recess 223b is closed, that is, the clutch angle is in a creep state of approximately 25 degrees. It will be done until Note that when the recess 223b is open, the recess 223
a is also open, so that the piston member 13
During the leftward movement of No. 2, the hydraulic oil in the left cylinder chamber 134 is
From the control oil passage L6 to the eighth and twelfth control oil passages Ls, L1
It is drained through □ and the recess 223a.

Therefore, the piston member 132 is rapidly moved to the left.

In this way, in this example, the manual valve 210
When the clutch 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 about 25 degrees).

Note that after being moved to the creep position, both recesses 223
Since the clutch control valves 223a and 223b are closed, the clutch control valve 220 operates in accordance with 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, for example, consider a case where the accelerator pedal is suddenly depressed to start the vehicle from the idling state a1. At this time, while the increase in engine speed is slightly delayed as described above, the throttle opening increases immediately and the throttle pressure PTFI moves the left spool 221 of the clutch control valve 220 to the left to open the clutch valve ( (reduce clutch angle)
It works like this. However, when the clutch angle becomes smaller from the idling state a1, the throttle pressure P that acts to move the left spool 221 to the left as described above decreases.
Since the hydraulic oil having TH is drained through the 25th control oil passage L25, the clutch valve will no longer open. Therefore, an appropriate engine load is maintained, a sudden increase in engine rotation and accompanying hunting are prevented, and a smooth latching connection is achieved.

In this way, it is possible to effectively suppress engine rotation hunting due to sudden depression of the accelerator pedal. By simply setting the characteristics of the parabolic lines A, B, and C as shown in FIG. 6, the above hunting can be prevented to some extent.

For example, consider a case where the accelerator pedal is suddenly depressed from the idling state indicated by point al, and the throttle opening becomes half open (the state indicated by line B). Immediately after this depression, the engine rotation remains at the idling rotation NI, so in the case of the characteristics according to the present invention, the extension of the line B shown by the broken line reaches the opening degree (approximately 12 degrees) at the point bI corresponding to this rotation N1. The clutch angle is about to open. In contrast,
- In the case of the conventional characteristic shown by the dotted chain line B', the opening degree corresponding to idling rotation is a negative value, and the valve is about to be opened fully (opening degree 0 degrees).

In this way, the characteristics of the present invention (characteristics shown by lines A, B, and C)
In this case, the amount of opening of the clutch valve in response to depression of the accelerator pedal is kept small.

Therefore, an excessive increase in engine speed is suppressed, and hunting is less likely to occur.

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

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, when the accelerator pedal is depressed, the power transmission capacity, that is, the clutch opening is determined from the throttle opening and engine rotation at this time.
This transmission capacity gradually increases as the engine speed increases (
The clutch is connected by gradually closing the clutch opening, but in this case, the change in clutch transmission capacity (the rate of change in the clutch opening in the closing direction) with respect to the increase in engine speed is When it is small (when the clutch valve is open) it is small, and when it is large (
(when the clutch valve is closed) is large, so when you press the accelerator pedal from the clutch open state to connect it, the clutch transmission capacity (clutch valve opening) does not change much with changes in engine speed immediately after pressing the accelerator pedal. , fluctuations in engine load can be suppressed to a small level, and an excessive increase in engine rotation can be suppressed. Therefore, even if the accelerator pedal is suddenly depressed, the engine rotation does not become excessively high, hunting does not occur, and the latch can be connected smoothly. In addition, when the engine is idling and in a creep state, the change in clutch transmission capacity (change in clutch valve opening) in response to changes in engine speed is small, and even if engine speed changes slightly, engine load does not change much. . Therefore, the idling state can be stabilized.

[Brief explanation of the drawing]

FIG. 1 is a hydraulic circuit diagram of a continuously variable transmission equipped 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 a diagram of the continuously variable transmission. 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, engine speed, and throttle opening. 1... Input shaft 8... Governor valve 10
...Charge pump 20...Forward/forward switching device 30
．． 50... Servo unit for speed change 95... Clutch valve body 97... Cam member 110... Shuttle valve 130... Clutch servo unit 140... Servo unit for forward and backward movement 210... Manual valve 220 ...Clutch control valve 272.27
4... Orifice change valve 260... Relief valve

Claims (1)

[Scope of Claims] 1) In a transmission that changes the speed of engine rotation input to an input shaft and transmits the same to an output shaft, a clutch that connects and disconnects power transmission between the input shaft and the output shaft by the transmission. The control device sets the power transmission capacity of the clutch to a predetermined value or less when the engine rotation is equal to or less than a first predetermined rotation speed when an index corresponding to the engine throttle opening is constant; The power transmission capacity is set to gradually increase to a maximum value as the rotation increases from the first predetermined rotation speed to a second predetermined rotation speed higher than the first predetermined rotation speed, and from the first predetermined rotation speed to the A shift characterized in that the rate of increase in the power transmission capacity with respect to the engine rotation when the engine rotation increases to a second predetermined rotation speed is controlled so as to increase in accordance with the increase in the power transmission capacity. Machine clutch control device.