JP2713741B2 - Hydraulic clutch device for hydraulic continuously variable transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic continuously variable transmission including a hydraulic pump and a hydraulic motor, and more particularly, to a direct-coupled clutch for intermittently controlling a hydraulic closed circuit connecting a pump and a motor. The present invention relates to a hydraulic clutch device including a valve and a main clutch valve that controls a short circuit of a hydraulic closed circuit thereof.

(Conventional technology) A continuously variable transmission including a hydraulic pump and a hydraulic motor has been conventionally known, and is used for various applications.
For example, JP-B-32-7159, JP-B-56-50
As disclosed in Japanese Patent Publication No. 142, a constant discharge type hydraulic pump is connected to an input shaft, discharge oil from the pump is guided to a variable displacement hydraulic motor via a hydraulic closed circuit, and the hydraulic motor is driven. There is a continuously variable transmission that drives an output shaft connected thereto.

In such a continuously variable transmission, a direct connection crack valve capable of intermittently connecting the hydraulic closed circuit is provided, the angle of the swash plate for variably controlling the capacity of the hydraulic motor is minimized, and the speed ratio of the transmission is set to "1". It is known that when this happens, the hydraulically-closed circuit is shut off by the direct-coupled clutch valve to rotate the pump and the motor integrally. It is also known that a main clutch valve capable of short-circuiting the hydraulic closed circuit is provided, and the short-circuit path of the hydraulic closed circuit is opened and closed by the main clutch valve to control the clutch opening.

By the way, a hydraulic clutch device composed of such a direct-coupled clutch valve and a main clutch valve will be described with reference to FIG. 7 taking the example of Japanese Patent Application No. 62-264841 proposed by the present applicant as an example.

A fixed shaft 202 is inserted into a hollow portion formed at an end of the motor cylinder 201, and a distribution ring fitted to the fixed shaft 202.
203 is eccentrically in sliding contact with the distribution board 204 of the motor cylinder 201. The distribution ring 203 divides the hollow portion of the motor cylinder 201 into an inner oil chamber that is a first oil passage La and an outer oil chamber that is a second oil passage Lb. The distribution board 204 includes a discharge path 205 from the hydraulic pump and a suction path of the pump (not shown).
, A suction passage 206 and a discharge passage (not shown) for the hydraulic motor are formed, and the pump discharge passage 205 and the motor suction passage 206 are communicated via the first oil passage La, and the second oil passage The pump suction path and the motor discharge path are communicated via Lb. Thus, the distribution ring 20 is provided between the hydraulic pump and the motor.
A hydraulic closed circuit is configured via the third and distribution boards 204.

The main clutch valve CL is configured to rotate the cylindrical main clutch valve body 210 fitted in the fixed shaft 202 so that the short-circuit ports 211a and 211b of the fixed shaft 202 and the short-circuit holes 212a and 212b of the main clutch valve body 210 are rotated. The clutch position is controlled by controlling the degree of overlap between the two holes.

The direct-coupled clutch valve DC includes a piston shaft 215 fitted movably in the axial direction within the main clutch valve body 210, a shoe 216 attached to the tip of the piston shaft 215, and a pilot inserted into the piston shaft 215. And a spool 217. Then, the lid 219 is fitted into the other end of the main clutch valve body 210, and the lid 219 and the piston shaft 215 are inserted.
An oil chamber 220 is formed therebetween. When the pilot spool 217 is moved to the left, the through hole 221 of the piston shaft 215 is closed by the pilot spool 217, and the high-pressure hydraulic oil from the pump discharge path 205 passes through the oil passages 222a and 222b of the piston shaft 215 to the oil chamber 220. And the piston shaft 215 is moved leftward. Due to this movement, the shoe 216 of the piston shaft 215 closes the pump discharge passage 205a, the first oil passage La is shut off, and the hydraulic pump and the hydraulic motor are directly connected (directly connected clutch ON state). Next, when the pilot spool 217 is moved to the right,
Since the small-diameter portion 223 of the pilot spool 217 communicates with the through hole 221, the high-pressure hydraulic oil is supplied through the through hole 221, the small-diameter portion 223, and the piston shaft.
The fluid flows into the annular chamber 225 through the through hole 224 of the 215, whereby the piston shaft 215 is moved rightward. With this movement, shoe 2
The blockage of the pump discharge path 205a by 16 is released, and the direct connection state (OFF state) between the hydraulic pump and the motor is released.

(Problems to be Solved by the Invention) However, in the hydraulic clutch device as shown in the above example, every time the direct coupling clutch valve DC is switched from ON to OFF, the collision sound between the main clutch valve body 210 and the lid body 219 is generated. There is a problem that occurs.

When the hydraulic pump is driven, ON / OF of the direct connection clutch valve DC
Regardless of F, since a part of the high-pressure hydraulic oil is constantly supplied to the oil chamber 220 through the oil passages 222a and 222b, the lid 219 is constantly pressed against the right thrust needle bearing 218 by the high-pressure oil. Have been. When switching the direct coupling clutch valve DC from ON to OFF, high pressure oil flows into the annular chamber 225 by the rightward movement of the pilot spool 217, but since the shoe 216 still closes the pump discharge path 205a in the initial stage of switching. The oil pressure in the first oil passage La (the inner oil chamber) is low. here,
Since the main clutch valve 210 and the lid 219 are merely fitted, the main clutch valve 210 is moved leftward due to the difference between the high pressure of the annular chamber 225 and the low pressure of the first oil passage La described above. Away from the lid 219. Then, piston shaft 2
When the pump discharge passage 205a is released by the rightward movement of 15, the first
Since the pressure in the oil passage La increases, the main clutch valve body 21
0 is moved to the right and comes into contact with the lid 219.

Thus, every time the direct-coupled clutch valve DC is switched from ON to OFF, the main clutch valve body 210 is
One end is separated from 19, and then comes into contact with the lid 210 again, so that a collision sound is generated at the time of the contact, and this is transmitted to the outside, resulting in a problem that an abnormal sound is generated.

In view of such a problem, the present invention prevents the movement of the main clutch valve element caused by the difference in oil pressure and the generation of a collision noise caused by the difference in oil pressure when the closed hydraulic circuit is released by the movement of the diameter clutch piston shaft. It is an object of the present invention to provide a hydraulic clutch device capable of performing such operations.

B. Configuration of the Invention (Means for Solving the Problems) As means for achieving this object, in the present invention, the hydraulic pump and the discharge / suction of the motor are integrally mounted on the end of the hydraulic motor cylinder in the rotation axis direction. Having a distribution plate formed with a distribution ring sliding contact surface having a port,
The cylindrical member is integrally connected to the end of the hydraulic motor cylinder and attached to the end of the hydraulic motor cylinder so as to cover the discharge / suction port on the distribution ring sliding contact surface, and the hollow fixed shaft positioned coaxially with the rotation axis of the hydraulic motor is provided in the cylindrical member. The distribution ring is fitted and fixed on this fixed shaft. The distal end of the distribution ring slides on the distribution ring sliding contact surface to form an inner space surrounded by the cylindrical member and the end of the cylinder of the hydraulic motor into an outer space on the outer peripheral side of the hollow fixed shaft and a hollow outer space. The fixed shaft is divided into an inner space communicating with the inner space, and the discharge port of the pump and the suction port of the motor are communicated through one of the outer space and the inner space, and the suction port and the motor of the pump are communicated through the other. To form a hydraulic closed circuit. Further, a cylindrical main clutch valve element is disposed in the inner space of the fixed shaft so as to be rotatable about its axis, and the rotation allows the outer space formed in the fixed shaft to communicate with the inner space. Controls the opening of the short circuit hole. A directly connected clutch piston shaft is slidably fitted in the main clutch valve body in the axial direction so as to be movable in the axial direction. With this movement, a distal end projecting from one end side of the main clutch valve body comes into contact with the distribution ring sliding contact surface to discharge the pump or A suction port is closed, and a lid forming a hydraulic oil chamber between the main clutch valve body and the directly-coupled clutch piston shaft is disposed opposite to the other end of the main clutch valve body. The lid is integrally connected to the other end of the main clutch valve.

(Operation) In the case of using the hydraulic clutch device having such a configuration, when the direct-coupled clutch piston shaft is moved and the cutoff of the hydraulic closed circuit is released (when it is turned from ON to OFF), the main clutch is moved from the left and right. Even if there is a difference in the applied hydraulic pressure, the lid is integrally connected to the other end of the main clutch valve, so that the main clutch valve does not move relative to the lid, and the two may collide. Does not occur.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a hydraulic circuit diagram of a continuously variable transmission to which the present invention is applied. In this figure, a continuously variable transmission T is a constant discharge type swash plate axial driven by an engine E via an input shaft 1. It has a plunger type hydraulic pump P and a variable displacement type swash plate axial plunger type hydraulic motor M which drives wheels (not shown) via a forward / reverse switching device 20. The hydraulic pump P and the hydraulic motor M are connected to a first oil passage La that communicates a discharge port of the pump P and a suction port of the motor M, and a second oil passage Lb that communicates a suction port of the pump P and a discharge port of the motor M. The two oil passages are connected to form a hydraulic closed circuit. The first of these two oil passages La and Lb
In the oil passage La, when the pump P is driven by the engine E and the motor M is rotated by the hydraulic pressure from the pump P to drive the wheels, that is, the wheels are driven by the engine E via the continuously variable transmission T. Is high (the second oil passage Lb is at a low pressure at this time).
The oil passage Lb has a high pressure when the engine brake is applied by receiving driving force from the wheels, such as when the vehicle is decelerating (at this time, the first oil passage La is at a low pressure).

In the first oil passage La, a direct connection clutch valve DC capable of connecting and disconnecting the oil passage La is provided.

A discharge port of a charge pump 10 driven by the engine E through a pair of gear sets 9a and 9b is provided with a charge oil passage Lh having a check valve 15 and a pair of check valves 3 and 3.
Is connected to a closed circuit via a third oil passage Lc having
The hydraulic oil pumped up from the oil sump 17 by the charge pump 10 and regulated by the charge pressure relief valve 16 is supplied to the two oil passages La,
It is supplied to the low pressure side oil passage of Lb.

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 the hydraulic oil into a governor oil pressure corresponding to the rotation speed of the engine E. In this figure, the input and output oil passages connected to the governor valve 8 are not shown.

A fourth oil passage Ld having a shuttle valve 4 is connected to the closed circuit. The shuttle valve 4 is connected to fifth and sixth oil passages Le and Lf which have high and low pressure relief valves 6 and 7 and are connected to an oil sump 17. The shuttle valve 4 is a two-port, three-position switching valve, which operates according to the oil pressure difference between the first and second oil passages La, Lb, and which operates on the high-pressure side of the first and second oil passages La, Lb. The passage is communicated with the fifth oil passage Le, and the oil passage on the low pressure side is communicated with the sixth oil passage Lf. Thereby, the relief oil pressure of the high pressure side oil passage is adjusted by the high pressure relief valve 6, and the relief oil pressure of the low pressure side oil passage is adjusted by the low pressure relief valve 7.

A seventh oil passage Lg for short-circuiting the two oil passages is also provided between the first and second oil passages La and Lb, and the seventh oil passage Lg has a variable throttle that controls the opening degree of the oil passage. A main clutch valve CL composed of a valve is provided.

An output shaft 28 is arranged in parallel with the rotary shaft 2 of the hydraulic motor M, and a forward / reverse switching device 20 is provided between the two shafts 2 and 28.
This device 20 is rotatably supported on an output shaft 28 and is meshed with the first drive gear 21 and first and second drive gears 21 and 22 arranged at intervals in the axial direction on the rotating shaft 2. First
A driven gear 23, a second driven gear 25 meshed with the second drive gear 22 via the intermediate gear 24, and rotatably supported on the output shaft 28, and output between the first and second driven gears 23, 25. Axis 2
8 and a sleeve 27 that is slidable in the axial direction and selectively connects the clutch hub 26 and the clutch gears 23a or 25a formed on the side surfaces of the driven gears 23 and 25, respectively. The sleeve 27 is moved left and right by a shift fork 29. The specific configuration of the forward / reverse switching device 20 is shown in FIG. In the forward / reverse switching device 20, the sleeve 27 is
In a state where the clutch gear 23a of the first driven gear 23 and the clutch hub 26 are connected as shown in FIG. Is rotated in the forward direction as the continuously variable transmission T is driven. On the other hand, when 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 rotary 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 coaxially disposed in a space surrounded by first to fourth cases 5a to 5d. The input shaft 1 of the hydraulic pump P is connected to the output shaft Es of the engine E via a coupling 1a. A centrifugal filter 50 is provided on the inner peripheral side of the coupling 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, and the charge pump 10 is driven. Is done. The drive shaft 11 penetrates through the charge pump 10 and protrudes on the side opposite to the gear 9b, and is also connected to the governor valve 8. For this reason, the rotation of the engine E is also transmitted to the governor valve 8, and the governor valve 8 creates a governor oil pressure corresponding to the rotation of the engine E.

The hydraulic pump P has a pump cylinder 60 spline-coupled to the input shaft 1 and a plurality of pump plungers 62 formed by sliding a plurality of cylinder holes 61 formed at equal intervals on the circumference of the pump cylinder 60. That is, 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 around the pump cylinder 60 and a plurality of motor plungers 72 slid into a plurality of cylinder holes 71 formed at equal intervals on the circumference of the motor cylinder 70. The pump cylinder 60 is relatively rotatable coaxially with the pump cylinder 60.

The motor cylinder 70 is constituted by first to fourth portions 70a to 70d which are integrally arranged side by side in the axial direction. The first portion 70a is rotatably supported by a case 5b via a bearing 79a on the outer periphery of a left end thereof, and a right inner side surface is inclined with respect to the input shaft 1 to constitute a pump swash plate member. Pump swash plate ring 63 on pump swash plate member
Is provided. The second portion 70b has the plurality of cylinder holes 71 formed therein, and the third portion 70c has the cylinder holes 61,
It has a distribution board 80 in which an oil passage to 71 is formed. Fourth part
70d is a flange portion 110, a first tubular portion 111 and a second tubular portion 1
A gear member GM having first and second drive gears 21 and 22 is press-fitted into the first cylindrical portion 111, and is connected to the third portion 70C by bolts 114 at the flange portion 110;
The case 5c via the bearing 79b in the second cylindrical portion 112
It is rotatably supported by.

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

Further, a swash plate member 73 facing each motor plunger 72.
Are swingably supported by the second case 5b 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 provided on a surface of the swash plate member 73 facing the motor plunger 72.
The motor shoe 74 is mounted on the motor swash plate ring 73b in sliding contact therewith. Motor shoe 74
Are swingably connected to the end of each motor plunger 72. The swash plate member 73 is connected to the piston rod 33 of the transmission servo unit 30 via a link member 39 at a position away from the trunnion shaft 73a. When moved in the direction, the swash plate member 73 is swung about the trunnion shaft 73a.

The fourth portion 70d of the motor cylinder 70 is formed to be hollow, and has a fixed shaft 91 fixed to the distribution board 18 at the center thereof.
Is inserted. A distribution ring 92 is fitted to the left end of the fixed shaft 91 in a liquid-tight manner, and the left end face in the axial direction of the distribution ring 92 is eccentric so that it can slide on the distribution plate 80. By this distribution ring 92, a hollow portion formed in the fourth portion 70d is partitioned into an inner oil chamber and an outer oil chamber, the inner oil chamber constituting a first oil passage La, and the outer oil chamber as a second oil chamber. The two oil passages Lb are configured.
The pressure distribution panel 18 includes a shuttle valve 4, high-pressure and low-pressure relief valves 6, 7, and the like.
And is covered by the fourth case 5d.

The detailed structure inside the distribution board 80 and the fourth portion 70d is shown in FIG. 3, and will be described below with reference to FIG.

The distribution board 80 is provided with a pump discharge port 81a and a pump suction port 82a, and through the discharge port 81a and the discharge passage 81b connected to the pump discharge port 81a and the cylinder hole 61 of the pump plunger 62 in the discharge stroke. A first oil passage La formed of an oil chamber communicates with the first oil passage La. A second hole formed of a cylinder hole 61 of a pump plunger 62 and an outer oil chamber in a suction stroke is provided through a pump suction port 82a and a suction passage 82b connected thereto. The oil passage Lb is communicated. Further, a communication path 83 communicating with the cylinder hole (cylinder chamber) 71 of each motor plunger 72 is formed in the distribution board 80, and the opening of the communication path 83 is Is connected to the first oil passage La or the second oil passage Lb in accordance with the rotation of. Therefore, the cylinder hole 71 of the motor plunger 72 in the expansion stroke and the first oil passage La communicate with the cylinder hole 71 of the motor plunger 72 in the contraction stroke and the second oil passage Lb via the communication passage 83, respectively. Is done.

In this way, a hydraulic closed circuit is formed between the hydraulic pump P and the hydraulic motor M via the distribution board 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 supplied from the pump discharge port 81a to the pump discharge passage 81b, the first oil passage La (inside oil chamber), and The fluid flows into the cylinder hole 71 of the motor plunger 72 in the expansion stroke through the communication path 83 which is in communication therewith, and gives 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 supplied to the second oil passage
Communication path 83 communicating with Lb (outside oil chamber), pump suction path 82b
And, it flows into the cylinder hole 61 of the pump plunger 62 in the suction stroke via the pump suction port 82a.

Due to such circulation of the hydraulic oil, the reaction torque given to the motor cylinder 70 by the pump plunger 62 in the discharge stroke via the pump swash plate ring 63 and the reaction torque received by the motor plunger 72 in the expansion stroke from the motor swash plate member 73 , 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, when the swash plate member 73 is swung by the shift servo unit 30 and the capacity of the hydraulic motor M is changed from 0 to a certain value, the speed ratio is changed 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 GM having first and second drive gears 21 and 22 is press-fitted and fixed to 70d. For this reason, the motor cylinder
The rotational driving force of 70 is transmitted to the output shaft 28 through the forward / reverse switching device 20.
Is transmitted to This output shaft 28 has a final gear set 28a,
The output shaft 28 is connected to the differential chandelier 100 via the 28b.
It is transmitted to 100. And the differential device 100
Thus, the rotational driving force divided into the left and right drive shafts 105 and 106 is transmitted to left and right wheels (not shown) to drive the vehicle.

The fixed shaft 9 inserted in the hollow member of the fourth portion 70d
In 1, a main clutch valve CL that forms a short circuit between the first oil passage La and the second oil passage Lb and controls the short circuit from fully closed to fully open, and intermittently controls the first oil passage La A possible direct coupling clutch valve DC is provided. These two clutch valves C
The structure of the L and DC will be described below with reference to FIG.

First, the main clutch valve CL will be described. Fixed axis
A short-circuit port 91 a through which the first oil passage La and the second oil passage Lb can be communicated is formed in the peripheral wall of the 91, and a cylindrical main clutch valve body 95 is inserted into the hollow portion of the fixed shaft 91. Have been.
The valve body 95 is rotatable relative to the fixed shaft 91, and has a short-circuit hole 95a that can be aligned with the short-circuit port 91a. By rotating an arm 95b formed at the right end of the valve body 95, the valve body 95 is rotated to make the short-circuit port 91a.
The amount of matching (overlap) between the wire and the short-circuit hole 95a can be adjusted. The size of the matching portion is the opening of the short-circuit passage between the first oil passage La and the second oil passage Lb. Therefore, by controlling the rotation of the valve element 95, the opening of the short-circuit passage is changed from fully open to fully closed. Can be controlled up to. If the opening degree of the short-circuit passage is fully open, the hydraulic oil discharged from the pump discharge port 81a to the first oil passage La flows directly from the short-circuit port 91a and the short-circuit hole 95a to the second oil passage La.
Since the oil flows into the oil passage Lb and also into the pump suction port 82a, the hydraulic motor M becomes inactive and the main clutch is turned off. On the contrary, if the opening of the short-circuit passage is fully opened, the main clutch ON state is realized.

At the center of the hollow main clutch valve body 95, a direct connection clutch valve DC is provided. This direct-coupled clutch valve DC
The piston shaft 85 is in sliding contact with the hollow hole of the main clutch valve body 95.
86a is screwed. The distal end of the valve rod 86a is formed to have a partial spherical surface, and the shoe 86 is coupled to the valve rod 86a via a mounting ring 86b so as to swing freely. In addition,
The shoe 86 is a spring 86c inserted between the shoe 86 and the valve rod 86a.
Biased to the left by

When the piston 86 moves to the left in the figure, the shoe 86 closes the opening end of the discharge passage 81b formed in the distribution board 80 and connected to the pump discharge port 81a in a liquid-tight manner, and the discharge port 81a
From the first oil passage La (inner oil chamber). And, as described above, in this shut-off state, the pump plunger 62 is hydraulically locked, the hydraulic pump P and the hydraulic motor M are directly connected, and the pump plunger 62 and the pump swash plate 63 are separated from the pump cylinder 60. Thus, the motory cylinder 70 is mechanically driven.

The piston shaft 85 is reduced in diameter on the right side with a step, and forms an oil chamber 87a between the piston shaft 85 and a lid 97 which is an inner member of a thrust needle bearing 96b that supports the main clutch valve body 95. I have. The oil chamber 87a includes an oil passage 89a which is normally formed in the piston shaft 85 along the axial direction, and an oil passage 89b which is formed in the center of the valve rod 86a so as to be able to communicate with the passage 89a. Through the first oil passage La. When the engine is driven, the hydraulic pump P and the hydraulic motor M
A part of the high-pressure hydraulic oil circulating between and is always supplied to the oil chamber 87a through the series of passages.

Here, a female thread 98 is formed on the inner periphery of the end of the main clutch valve body 95, and a male thread 99 is formed on the outer periphery of the boss of the lid 97. And these two screw parts 98,99
The lid 97 is integrally connected to the main clutch valve body 95 by screwing. Accordingly, the high pressure oil constantly supplied to the oil chamber 87a causes the lid 97 to always be in the thrust needle bearing.
Although it is pressed against 96b, since the lid body 97 and the main clutch valve body 95 are integrally coupled, the main clutch valve body 95 is also positioned while being biased rightward.
The two screw portions 98 and 99 are screwed liquid-tight by applying a sealant in advance.

A piston portion 85a is provided at an axially intermediate portion of the piston shaft 85.
An annular chamber 87b is formed on the left side of the piston portion 85a between the inner surface of the hollow hole of the main clutch valve body 95 and the outer peripheral surface of the piston shaft 85.
Furthermore, at the center of the piston shaft 85, the piston section starts from the right end face.
A blind hole 88 exceeding 85a is formed.
8. An escape groove 88a is formed on the innermost peripheral surface. A space between the stop hole 88 and the annular chamber 87b can be communicated with the piston shaft 85 via a through hole 89c formed in the radial direction. Further, a through hole 89d is formed in the vicinity of the right end surface of the piston portion 85a so as to communicate the oil passage 89a and the stop hole 88.

A rod-shaped pilot spool 84 is provided in the blind hole 88.
Is inserted. At the tip of the pilot spool 84, a land portion 84a that fits into the inner peripheral surface of the blind hole 88 is formed.On the right side of the land portion 84a, a small-diameter portion 84b having an appropriate axial dimension is provided. Is formed. Further, at the center of the pilot spool 84, an atmosphere communication hole 89e for communicating the inside of the non-stop hole 88 with the atmosphere is formed. This pilot spool 84 has a ball joint member at its outermost end.
A sliding operation is performed in the left and right direction by a link arm 46 engaged via 47. The description of the operation of the link arm 46 is omitted.

 In the above configuration, the dimensions of each part are as follows: the pressure receiving area of the end face of the shoe 86: A the cross-sectional area of the piston part 85a: B the pressure receiving area of the inner end side of the piston shaft 85: C the cross-sectional area of the reduced diameter part of the piston shaft 85 : D, the inequality A> (BD) (BD)> C is satisfied.

Here, when the pilot spool 84 is moved to the left,
Since the small-diameter portion 84b of the pilot spool 84 is entirely fitted into the blind hole 88 inward from the right end surface of the piston portion 85a, the through hole 89d is closed from the outer peripheral surface of the pilot spool 84, and the discharge port 81a is closed. The high-pressure hydraulic oil in the oil passages 89a, 8
The oil flows into the oil chamber 87a via 9b, and the oil pressure acts on the right end face of the piston portion 85a and also acts on the left end face of the piston shaft 85 from the first oil passage La side. At this time, since the pressure receiving area of the right end face of the piston portion 85a is (BD) and the pressure receiving area of the inner end face of the piston shaft 85 is C, the relation of the inequality (BD)> C is satisfied. Thus, the piston shaft 85 moves to the left. Shoe 86 with movement of piston shaft 85
Abuts against and closes the end face of the discharge passage 81b communicating with the discharge port 81a of the distribution board 80, and a direct connection between the hydraulic pump P and the hydraulic motor M is realized.

In this state, high-pressure hydraulic oil from the discharge port 81a (equal to the oil pressure of the oil chamber 87a) acts on the end face of the shoe 86 having the pressure receiving area A, while the pressure receiving area (B− The high-pressure hydraulic oil in the oil chamber 87a acts on the right end face having D). By the way, since both pressure receiving areas have a relationship of the inequality A> (BD), a force acts on the shoe 86 to move the shoe 86 to the right. When the shoe 86 moves to the right even slightly, the hydraulic pressure on the end face of the shoe 86 is released, and the shoe 86 is pressed against the end face of the distribution board 80 again.

In this way, by setting each of the pressure receiving areas of A, B and C to a predetermined value so as to satisfy the above inequality, a so-called hydraulic floating state can be maintained, and the communication between the shoe 86 and the discharge passage 81b is established. A good oil-tight state between them can be maintained while minimizing leakage of hydraulic oil from between them.

Next, when the pilot spool 84 is moved to the right,
The small diameter portion 84b of the pilot spool 84 communicates with a through hole 89d formed in the piston shaft 85. As a result, the high-pressure hydraulic oil is supplied to the piston shaft 85 at the same time as the right end face of the piston portion 85a.
In addition to acting on the left end face of, the through hole 89d, the small diameter portion 84b, the communication hole
It also acts on the left end face of the piston part 85a through the 89c and the annular chamber 87b. At this time, while the pressure receiving area for moving the piston shaft 85 to the left is (BD), the pressure receiving area for moving the piston shaft 85 to the right is B, and B>
Since (BD), the piston shaft 85 moves to the right, and the direct connection state between the hydraulic motor M and the hydraulic pump P is released.
As can be understood from the above, when the pilot spool 84 is moved in the left-right direction, the piston shaft 85 follows
Is also moved in the left-right direction, and the direct connection clutch valve DC is turned ON / OFF.

The movement of the pilot valve 84 in the left-right direction is performed via a link mechanism 40 disposed on the side of the pressure distribution panel 18. Therefore, the link mechanism 40 will be described.

FIG. 5 shows the link mechanism 40,
40 is the first having the first and second rotating arms 42a and 42b.
A shaft 42 and a second shaft 45 disposed below and parallel to the first shaft 42;
42, 45 are rotatably supported by bearings 49a, 49b, 49c fixed to the case 5a.

The first rotating arm 42a is connected to the pilot spool of the transmission servo unit 30 via the first link 41. The second rotary arm 42b is rotated by being actuated by a hydraulic cylinder or the like. With this rotation, the first rotary arm 42a is also rotated to move the pilot spool of the servo unit 30 for shifting right and left. Move to When the pilot spool is moved to the left and right, the piston rod 33 is configured to move in accordance with the movement, whereby the swing control of the swash plate member 73 of the motor M is performed.

A third pivot arm 46 is fixed to the second shaft 45, and the third pivot arm 46 is a ball joint member.
It is connected via 47 to a pilot valve 84 of a directly connected clutch valve DC. Therefore, when the third rotation arm 46 is rotated with the rotation of the second shaft 45, the pilot valve 84 is moved right and left, and the ON / OFF operation of the direct coupling clutch valve DC is performed. The third rotating arm 46 is always controlled by a pilot valve 84 by a torsion coil spring 46a wound around the second shaft 45.
Is pushed outward (to the right).

On the other hand, driving and driven cams 43 and 44 meshing with each other are fixed to the first and second shafts 42 and 45, and these cams 43 and 44 are rotated according to the rotation of the first shaft 42.
A constant rotation is given to the second shaft 45 by the action of.

The operation of the cams 43 and 44 will be described with reference to FIGS. 6A to 6C. As shown in these figures, the driving cam 43
Is a semicircular portion having a semicircular arc centered on the first shaft 42
43a, a convex portion 43b projecting partly outward from the radius of the semicircular portion 43a, and a concave portion 43c partially recessed inside the radius of the semicircular portion 43a. It is formed in a smoothly continuous contour. On the other hand, the driven cam 44
Is an arc-shaped portion 44a composed of a concave surface having a curvature substantially equal to that of the semicircular portion 43a.
And a straight portion 44b extending substantially from the arc-shaped portion 44a in the battle direction.

First, the first rotating arm 42a is rotated counterclockwise by the second rotating arm 42b, and accordingly, the inclination of the swash plate member 73 of the hydraulic motor M is maximized by the shifting servo unit 30 (at this time, the shifting is performed). Ratio is the maximum),
As shown in FIG. 6A, the semicircular portion 43a of the drive cam 43 is
4, the projection 43b of the driving cam 43 and the straight portion 44b of the driven cam 44 are separated from each other. Therefore, the third rotating arm 46 receives the urging force of the torsion coil spring 46a to move the pilot valve 84 rightward, and the direct-coupled clutch valve DC is in a fully opened state.

From this state, when the second rotation arm 42b is rotated clockwise to reduce the inclination angle of the swash plate member 73, the first shaft 42 is rotated clockwise and the first servo unit 30 The plate member 73 is rotated clockwise about the trunnion shaft 73a, the inclination angle becomes smaller, and the gear ratio becomes smaller. At this time, the driving cam 43 is also rotated with the rotation of the first shaft 42, but the driven cam 44 is not rotated until the projection 43b of the driven cam 43 abuts on the straight portion 44b. Therefore, the pilot valve 84 is not moved, and the direct-coupled clutch valve DC is maintained in the fully opened state.

The second rotation arm 42b is further moved upward to move the swash plate member 73.
When the gear ratio becomes "1" (minimum), the convex portion 43b of the driving cam 43 rotated clockwise together with the first shaft 42 becomes straight, as shown in FIG. 6B. It comes into contact with the shape portion 44b.

When the second rotating arm 42b is further rotated clockwise from this state, the first shaft 42 is further rotated clockwise, and the spool member 34 of the first servo unit 30 is further moved rightward. However, further rotation of the motor trunnion 73 is prevented by the stopper, and the motor trunnion 73 is held upright. However, since the first shaft 42 is rotated, the drive cam 43 is rotated clockwise, and as shown in FIG. 6C, the straight portion 44b is pushed by the convex portion 43b of the drive cam 43. , The driven cam 44 is rotated clockwise.

When the driven cam 44 is rotated clockwise in this manner, the second shaft 45 and the third rotation arm 46 are also rotated against the urging force of the torsion coil spring 46a, and as a result, the pilot valve 84 Is pushed to the left. As a result, the piston shaft 85 is moved to the left as described above, and the shoe 86 closes the pump discharge path 81b to realize a directly connected state (the ON state of the directly connected clutch valve DC).

By the way, when the hydraulic pump P is driven, a part of the high-pressure hydraulic oil is supplied to the oil passage 8 regardless of ON / OFF of the direct connection clutch valve DC.
9a, 89b, the lid 97 is always supplied to the oil chamber 87a.
Pressed to 96b. As described above, when the direct-coupled clutch valve DC is switched from ON to OFF, high-pressure oil flows into the annular chamber 87b due to the rightward movement of the pilot spool 84, but in the initial stage of switching, the shoe 86 moves through the discharge path 81b. Since it is still closed, the pressure in the first oil passage La (the inner oil chamber) is low. Therefore, due to the difference between the high pressure of the annular chamber 87b and the low pressure of the first oil passage La, a force acts on the main clutch valve body 95 to move the main clutch valve body 95 to the left.

However, as described above, the main clutch valve body 95
The main clutch valve body 95 moves with respect to the cover body 97 and separates even if there is a difference in oil pressure as described above. I will not do it. Therefore, turn the direct-coupled clutch valve DC from ON to OFF.
Each time is switched, the occurrence of collision noise between the main clutch valve body 95 and the lid body 97 is prevented.

In the above example, the configuration in which the lid body is screwed to the main clutch valve body and the two are integrally coupled has been described. However, the coupling method is not limited to this, and other coupling methods may be used. Of course it is good.

C. Effect of the Invention As described above, according to the present invention, a lid for forming a hydraulic oil chamber between the direct coupling clutch piston shaft,
Since it is integrally connected to the other end of the main clutch valve body, even when there is a difference in the hydraulic pressure applied to the main clutch valve body when the direct-coupled clutch piston shaft is moved and the shutoff of the hydraulic closed circuit is released. This prevents the main clutch valve from moving relative to the lid. Accordingly, it is possible to prevent the generation of a collision sound between the main clutch valve body and the lid, and to obtain a hydraulic continuously variable transmission that does not generate abnormal noise.

[Brief description of the drawings]

1 is a hydraulic circuit diagram of a hydraulic continuously variable transmission to which the present invention is applied, FIG. 2 is a cross-sectional view of the continuously variable transmission, and FIGS. 3 and 4 are hydraulic clutch devices of the continuously variable transmission. FIG. 5 is a perspective view showing a link mechanism for controlling the operation of a direct-coupled clutch valve; FIG. 6A to FIG. 6C are front views showing the operation of a cam constituting the link mechanism; FIG. 7 is a sectional view showing a conventional hydraulic clutch device. 4 Shuttle valve, 20 Forward / reverse switching device 30 Speed change servo unit 60 Pump cylinder, 70 Motor cylinder 80 Distribution board, 84 Pilot spool 92 Distribution ring, 95 … Main clutch valve element 97 …… Lid, P …… Hydraulic pump M …… Hydraulic motor, CL …… Main clutch valve DC …… Direct coupling clutch valve

Claims (1)

(57) [Claims] 1. A hydraulic pump connected to an input shaft and a hydraulic motor connected to an output shaft are connected via a hydraulic closed circuit.
In the hydraulic continuously variable transmission that drives the hydraulic motor by hydraulic pressure from the hydraulic pump, the hydraulic motor is integrally connected to an end of a cylinder of the hydraulic motor in a rotation axis direction, and the cylinder of the hydraulic pump rotates. A distribution plate having a pump sliding contact surface that freely slides and a distribution ring sliding contact surface having discharge and suction ports of the hydraulic pump and the hydraulic motor formed on a side opposite to the pump sliding contact surface; A hollow cylindrical member which is integrally connected to an end of a cylinder of the hydraulic motor so as to cover the discharge and suction ports in the distribution ring sliding contact surface, and which is located coaxially with a rotation axis of the hydraulic motor and has a tip A hollow fixed shaft having a portion protruding into the cylindrical member and fixedly arranged; a distributing ring slide fitted and mounted on the fixed shaft; An inner space which is disposed in sliding contact with the contact surface and is surrounded by the cylindrical member and an end of the cylinder of the hydraulic motor; an outer space on the outer peripheral side of the hollow fixed shaft; and the hollow fixed shaft. And a discharge port of the pump and a suction port of the motor through one of the outer space and the inner space, and a suction port of the pump through the other. A distribution ring for communicating with a discharge pump of the motor to form the hydraulic closed circuit; and a distributing ring rotatably disposed around an axis of the fixed shaft in an internal space of the fixed shaft. A cylindrical main clutch valve body for controlling an opening degree of a short circuit hole that communicates the outer space and the inner space formed in the main clutch valve body; Yo A direct-coupled clutch piston shaft that has a distal end projecting from one end of the main clutch valve body abutting on the distribution ring sliding contact surface to close a discharge or suction port of the pump, Arranged opposite to each other,
A cover that forms a hydraulic oil chamber with the directly-coupled clutch piston shaft, wherein the cover is integrally connected to the other end of the main clutch valve body. Hydraulic clutch device for transmission.