JPH0289866A - Hydraulic clutch device for hydraulic continuously variable transmission - Google Patents

Abstract

PURPOSE:To prevent the occurrence of colliding sound accompanied with the movement of a clutch valve body by combining a cover plate provided for forming an operating oil damper at halfway the distance from a directly connected clutch piston shaft, monolithically with the end of a main clutch valve body. CONSTITUTION:When a directly connected clutch valve body DC is switched from 'ON' to 'OFF', highly pressurized oil enters into a circular chamber 87b owing to the movement of a pilot spool 84 to the right. However, the inside of No.1 oil passage La (inside oil chamber) is low in pressure at an early stage because a discharge passage 81b is still blocked by a shoe 86, a main clutch valve body 95 is thereby subjected to force which makes the valve body move to the left because of the difference between high pressure in the circular chamber 87b and low pressure in No.1 passage La. The cover plate 97 is, however, monolithically combined with the main clutch valve body 95 by means of threaded sections 98 and 99, the main clutch 95 thereby will never be moved against the cover plate 77 so as to be separated, even if there exists the difference in pressure. This constitution thereby permits the occurrence of colliding sound between the main clutch valve body 95 and the cover plate 97.

Description

DETAILED DESCRIPTION OF THE INVENTION A.Objective of the Invention (Field of Industrial Application) The present invention relates to a hydraulic continuously variable transmission comprising a hydraulic pump and a hydraulic motor, and more specifically relates to a hydraulic continuously variable transmission comprising a hydraulic pump and a hydraulic motor. The present invention relates to a hydraulic clutch device that includes a direct clutch valve that performs intermittent control on a hydraulic closed circuit, and a main clutch valve that performs short-circuit control on the hydraulic closed circuit.

(Prior Art) Continuously variable transmissions composed of a hydraulic pump and a hydraulic motor have been known for a long time and are used for various purposes. −
For example, Tokuko Publication No. 32-7159, Tokuko Publication No. 5
As disclosed in Publication No. B-50142, a constant discharge amount type hydraulic pump is connected to an input shaft, and the oil discharged from this pump is guided to a variable displacement type hydraulic motor through a closed hydraulic circuit. There is a continuously variable transmission that drives an output shaft connected to the transmission.

In such a continuously variable transmission, a directly connected Clara valve that can connect and disconnect the hydraulic closed circuit is provided, so that the angle of the swash plate that variably controls the capacity of the hydraulic motor is minimized, and the gear ratio of the transmission is
1", it is known that this direct-coupled clutch valve cuts off the hydraulic closed circuit and allows the pump and motor to rotate as one. Additionally, a main clutch valve is provided that can short-circuit the hydraulic closed circuit. It is known that the main clutch valve opens and closes a short circuit of a hydraulic closed circuit to control the clutch opening degree.

By the way, a hydraulic club device consisting of such a direct clutch valve and a main clutch valve is described in Japanese Patent Application No. 62-264841, proposed by the present applicant, as an example.
This will be explained with reference to the figures.

A fixed shaft 202 is inserted into a hollow portion formed at the end of the motor cylinder 201, and a distribution ring 203 fitted onto the fixed shaft 202 is eccentrically slidably contacted with a distribution plate 204 of the motor cylinder 201.

This distribution ring 203 divides the hollow portion of the motor cylinder 201 into an inner oil chamber, which is a first oil passage La, and an outer oil chamber, which is a second oil passage Lb. The distribution board 204 has a discharge passage 205 from the hydraulic pump and a pump suction passage (not shown), and a suction passage 20B and a discharge passage (not shown) to the hydraulic motor. The pump discharge passage 205 and the motor suction passage 206 communicate with each other via the passage La, and the pump suction passage and the motor discharge passage communicate with each other via the second oil passage Lb. In this way, a hydraulic closed circuit is constructed between the hydraulic pump and the motor via the distribution ring 203 and the distribution board 204.

The main clutch valve CL rotates the cylindrical main clutch valve body 210 fitted into the fixed shaft 202, thereby connecting the short circuit ports 211a, 211b of the fixed shaft 202 and the short circuit holes 212a, 212b of the main clutch valve body 210.
Clutch control is performed by changing the relative position between the two holes and controlling the degree of overlap between the two holes.

The direct coupling clutch valve DC includes a piston shaft 215 fitted into the main clutch valve body 210 so as to be movable in the axial direction, and a shoe 21 attached to the tip of the piston shaft 215.
6 and a pilot spool 217 inserted into the piston shaft 215. And the lid body 219
is fitted into the other end of the main clutch valve body 210, and an oil chamber 220 is formed between the cover body 219 and the piston shaft 215. When the pilot spool 217 is moved to the left, the pilot spool 217 closes the through hole 221 of the piston shaft 215, and the high-pressure hydraulic oil from the pump discharge passage 205 enters the oil chamber 220 through the oil passages 222a and 222b of the piston shaft 215. flow, thereby causing the piston shaft 215
is moved to the left. Due to this movement, the shoe 216 of the piston shaft 215 closes the pump discharge passage 205a, the first oil passage La is cut off, and the hydraulic pump and the hydraulic motor are brought into a direct connection state (direct connection clutch ON state). Next, when the pilot spool 217 is moved to the right, the pilot spool 21
7 communicates with the through hole 221, high-pressure hydraulic oil flows into the annular chamber 225 through the through hole 221, the small diameter portion 223, and the through hole 224 of the piston shaft 215, which causes the piston shaft 215 to move to the right. be moved. This movement releases the pump discharge passage 205a from being blocked by the shoe 216, and the direct connection state (OFF state) between the hydraulic pump and the motor is released.

(Problem 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, a collision noise between the main clutch valve body 210 and the lid body 219 is generated. There is a problem that occurs.

When driving the hydraulic pump, turn on the direct coupling clutch valve DC.
Regardless of whether it is OFF, a portion of the high-pressure hydraulic oil is in the oil passage 222a.
, 222b, the lid body 219 is always pressed against the right thrust needle bearing 218 by the high pressure oil. When switching the direct coupling clutch valve DC from ON to OFF, high pressure oil flows into the annular chamber 225 by the right movement of the pilot spool 217, but at the initial stage of switching, the shoe 216 is still blocking the pump discharge passage 205a. , first oil passage L
The oil pressure in a (inner oil chamber) is low.

Here, since the main clutch valve body 210 and the lid body 219 are simply fitted, the above-mentioned annular chamber 22
Due to the difference between the high pressure at No. 5 and the low pressure at the first hb path La, the main clutch valve body 210 is moved to the left and separated from the lid body 219. Thereafter, when the pump discharge passage 205a is released by moving the piston shaft 215 to the right, the pressure in the first oil passage La increases, so the main clutch valve body 210 is moved to the right and comes into contact with the lid body 21θ.

In this way, each time the direct coupling clutch valve DC is switched from ON to OFF, the main clutch valve body 210 is
is separated from the lid body 219 at one end and then comes into contact with the lid body 210 again, so there is a problem in that a collision sound is generated at the time of this contact, and this is transmitted to the outside and becomes an abnormal noise.

In view of these problems, the present invention has been developed to provide a system that, when unblocking a hydraulic closed circuit by moving a direct clutch piston shaft,
It is an object of the present invention to provide a hydraulic clutch device that can prevent the movement of a main clutch valve body caused by a difference in oil pressure and the generation of collision noise caused by this movement.

9. Structure of the Invention (Means for Solving the Problem) As a means for achieving this object, the present invention includes a hydraulic clutch device that includes a hollow cylindrical member integrally formed with a cylinder of a hydraulic motor, a hydraulic pump, and A distribution board provided with an oil passage communicating with a hydraulic motor, a hollow fixed shaft inserted into a cylindrical member, and a fixed shaft inserted into the fixed shaft so as to be rotatable about its axis. a cylindrical main clutch valve body that controls the degree of short circuit communication in the hydraulic closed circuit;
A direct-coupled clutch piston shaft that is slidably movable in the axial direction within the main clutch valve body, and through this movement controls the connection and disconnection of a hydraulic closed circuit at one end; A hydraulic clutch device is constituted by a lid that forms a hydraulic oil chamber between the clutch piston shaft and the lid, and the lid is integrally connected to the other end of the main clutch.

(Function) When using a hydraulic clutch device with such a configuration, when the direct coupling clutch piston shaft is moved and the hydraulic closed circuit is released from being cut off (when turning from ON to OFF), the main clutch is connected from the left and right. Even if there is a difference in the applied oil pressure, since the lid body is integrally connected to the other end of the main clutch valve body, the main clutch valve body will not move relative to the lid body, and collision between the two will not occur. will not occur.

(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 to which the present invention is applied. It includes a plunger type hydraulic pump P and a variable displacement swash plate axial plunger type hydraulic motor M that drives wheels (not shown) via a forward/reverse switching device 20. These hydraulic pump P and hydraulic motor M have a second oil passage La that communicates the discharge port of the pump P and the suction port of the motor M, and a second oil passage Lb that communicates the suction port of the pump P and the discharge port of the motor M. The two oil passages form a hydraulic closed circuit and are connected. Of these two oil passages La and Lb, the first 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. E
When the wheels are driven via the continuously variable transmission T,
The pressure becomes high (at this time, the second oil passage Lb is at low pressure)
On the other hand, the second 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). .

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

The discharge port of the charge pump 10 driven by the engine E via a pair of gears tf19a, 9b is connected via a charge oil passage Lh having a check valve 15 and a third oil passage Lc having a pair of check valves 3, 3. Connected to a closed circuit. Charge pressure is pumped up from the oil sump 17 by the charge pump 10 and applied to the charge pressure relief valve 16.
The hydraulic oil whose pressure has been regulated is supplied to the low pressure oil passage of the two oil passages L a + L b by the action of the check valves 3 , 3 .

A governor valve 8 is attached coaxially with this 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 are not shown in this figure.

A fourth oil passage Ld having a shuttle valve 4 is connected to the closed circuit. This shuttle valve 4 has high pressure and low pressure relief valves 6.7 for oil sump 17.
The fifth and sixth oil passages Le and Lf are connected to each other. The shuttle valve 4 is a 2-point/3-position switching valve, and operates according to the oil pressure difference between the first and second oil passages La, Lb. The oil passage is communicated with the fifth oil passage Le, and the low pressure side oil passage is communicated with the sixth oil passage Lf. As a result, the relief oil pressure in the oil passage on the high pressure side is regulated by the high pressure relief valve 6, and the relief oil pressure in the oil passage on the low pressure side is regulated by the low pressure relief valve 7.

A seventh oil passage Lg that short-circuits both passages is also provided between the first and second oil passages L a + L b.
A main clutch valve CL consisting of a variable throttle valve that controls the opening degree of this oil passage is disposed in the oil passage Lg.

An output shaft 28 is disposed parallel to the rotating shaft 2 of the hydraulic motor M, and forward and backward switching devices a and 20 are provided between both shafts 2 and 28. This device 20 includes first and second drive gears 21, 22 arranged on the rotating shaft 2 with an axial distance therebetween;
The first wave gear 23 is rotatably supported by the output shaft 28 and meshes with the first drive gear 21, and the first wave gear 23 meshes with the second drive gear 22 via an intermediate gear 24 and the output shaft 28.
A second driven gear 25 is rotatably supported by a clutch hub 2θ, a clutch hub 2θ is fixed to the output shaft 28 between the first and second wave gears 23.25, and a clutch hub 26 is slidable in the axial direction. A sleeve 27 selectively connects the clutch gears 23a or 25a formed on the side surfaces of the driven gears 23 and 25, respectively.
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, the switch IJ-bu 27
is slid leftward in the figure by the shift fork 29 and the clutch gear 23a of the first driven gear 23 and the clutch hub 26 are connected as shown in the figure, the output 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, sleeve 27
is slid to the right by the shift fork 29 and the clutch gear 25a of the second wave gear 25 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. is rotated to

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

This continuously variable transmission T is configured such that a hydraulic pump P and a hydraulic motor M are disposed together in a space surrounded by first to fourth cases 5a to 5d. The input shaft 1 of the hydraulic pump P connects to the output shaft E of the engine E via a coupling 1a.
It is combined with s. A centrifugal filter 50 is disposed on the inner peripheral side of this coupling 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 and 9b, and the charge pump 10 is driven. be done. 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.
The governor hydraulic pressure corresponding to the rotation of is created.

The hydraulic pump P includes a pump cylinder 60 spline-coupled to the input shaft 1, and a plurality of pump plungers 62 that slide into 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 surrounding the pump cylinder 60, and a plurality of motor plungers 72 that slide into a plurality of cylinder holes 71 formed in the motor cylinder 70 at equal intervals on the circumference. It is designed to be able to 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 83 is rotatably supported by the case 5b 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. Second portion 70b
The plurality of cylinder holes 71 are formed in the third portion 70c, and the third portion 70c has a distribution plate 80 in which an oil passage to each cylinder hole 61.71 is formed. The fourth portion 70d is the flange portion 1
101 consists of a first cylindrical part 111 and a second cylindrical part 112, and is connected to the third part 70C by bolts 114 at the flange part 110.
The gear member GM including the second drive gear 21 and 22 is press-fitted, and the bearing 79b is inserted into the second cylindrical portion 112.
It is rotatably supported by case 5C via.

An annular pump shoe 64 is rotatably and slidably attached on 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. pump shoe 6
4 and the pump cylinder 80 have bevel gears 88 that mesh with each other.
a and 68b are formed. Therefore, when the pump cylinder 60 is rotationally driven from the input shaft 1, the pump shoe 04
The pump plunger 62 is reciprocated in accordance with the inclination of the pump swash plate ring 63 to suck oil from the suction port and discharge oil to the discharge port.

Also, a swash plate member 73 facing each motor plunger 72
The second case 5b is connected to the second case 5b via a pair of trunnion shafts (swing shafts) 73a that protrude from both outer ends in a direction perpendicular to the paper surface.
It is swingably supported by. A motor swash plate ring 73b is disposed on the surface of the swash plate member 73 facing the motor plunger 72, and a motor shoe 74 is attached in sliding contact with the motor swash plate ring 73b.

The motor shoe 74 is swingably connected to the end of each motor plunger 72. This swash plate member 73 is connected to the link member 3 at a position away from the trunnion shaft 73a.
9, and when the piston rod 33 is moved in the axial direction by the speed changing servo unit 30, the swash plate member 73 swings about the trunnion shaft 73a. It is designed to be moved.

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 this fixed shaft 91, and the M of this distribution ring 92 is
The left end surface in the linear direction is eccentric so that it can come into sliding contact with the distribution board 80.

This distribution ring 92 divides the hollow portion formed in the fourth portion 70d into an inner oil chamber and an outer oil chamber, where the inner oil chamber constitutes the first oil passage La and the outer oil chamber constitutes the first oil chamber. 2 oil passages Lb are configured. Note that the pressure distribution board 18 is connected to the shuttle valve 4.
, high pressure and low pressure relief valves 6.7, etc., are attached to the right side of the third case 5c, and
It is covered by a fourth case 5d.

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

The distribution board 80 is provided with a pump discharge boat 81a and a pump suction boat 82a.
1a and the discharge passage 81b connected thereto, the cylinder hole 61 of the pump plunger 62 in the discharge stroke communicates with the first oil passage La consisting of an inner oil chamber. The cylinder hole 61 of the pump plunger +62 in the suction stroke communicates with the second oil passage Lb consisting of the outer oil chamber via the passage 82b.

Further, the distribution board 80 is formed with a communication path 83 that communicates with the cylinder hole (cylinder chamber) 71 of each motor plunger 72 . It is communicated with the first oil passage La or the second oil passage Lb depending on the rotation of the oil passage. For this reason,
Cylinder hole 71 of motor plunger 72 during expansion stroke
and the first oil passage La, and the cylinder hole 71 of the motor plunger 72 in the contraction stroke and the second oil passage Lb are communicated via the communication passage 83, respectively.

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, the high pressure hydraulic oil generated by the discharge stroke of the pump plunger 62 is transferred from the pump discharge port 81a to the pump discharge passage 81b1 and the first oil passage La (inner oil chamber). It flows into the cylinder hole 71 of the motor plunger 72 in the expansion stroke through the communication path 83 which is in communication with the motor plunger 72, and applies a ta force 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 communication path 83 communicating with the second oil path Lb (outer oil chamber), the pump suction path 82b, and the pump suction port 82a. pump plunger 62
It flows into the cylinder hole 61 of.

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 0 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, the gear member GM having the first and second drive gears 21 and 22 is press-fitted and fixed into the fourth portion 70d of the motor cylinder 70. Therefore, the rotational driving force of the motor cylinder 70 is transmitted to the output shaft 28 via the forward/reverse switching device 20. This output shaft 28 is connected to a differential device 100 via a final gear set 28a, 28b, and the rotational driving force of the output shaft 28 is transmitted to the differential device 100. The rotational driving force divided between the left and right drive shafts 105 and 106 by the differential device 100 is
The signal is transmitted to the left and right wheels (not shown) to drive the vehicle.

In addition, in the fixed shaft 91 inserted into the hollow part of the fourth part 70d, a short-circuit path is formed between the first oil passage La and the second oil passage Lb (!-), and this short-circuit path is opened from fully open to fully open. A controllable main clutch valve CL1 and a direct coupling clutch valve DC capable of controlling the first oil passage La on and off are provided.The structures of these clutch valves CL and DC will be described below with reference to FIG. 4 as well.

First, the main clutch valve CL will be explained. A short-circuit bow 91a is bored in the peripheral wall of the fixed shaft 9 to connect the first oil passage La and the second oil passage Lb, and a cylindrical main clutch valve is installed in the hollow part of this fixed shaft 91. body 95 has been inserted. This 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 boat 91a. By rotating the arm 95b formed at the right end of the valve body 95, the valve body 95
5 can be rotated to adjust the alignment (overlap > m) between the shorting boat 91a and the shorting hole 95a. Therefore, by controlling the rotation of the valve body 95, the opening degree of the short circuit passage can be controlled from fully open to fully closed.If the opening degree of the short circuit passage is fully open, the pump discharge port The hydraulic oil discharged from 81a to the first oil passage La is
Since the oil directly flows into the second oil passage Lb from the short-circuit boat 91a and the short-circuit hole 95a and also flows into the pump suction boat 82a, the hydraulic motor M becomes inactive and the main clutch becomes OFF. Of course, on the contrary, if the short-circuit passage is fully opened, the main clutch is in the ON state.

A direct coupling clutch valve DC is provided in the center of the hollow main clutch valve body 95. A piston shaft 85 of this direct coupling clutch valve DC is slidably engaged with a hollow hole of a main clutch valve body 95, and a valve rod 86a is screwed onto the tip of this piston shaft 85. valve rod 88
The tip of a is formed into a partially spherical surface, and a shoe 86 is swingably connected thereto via a mounting ring 86b. Note that the shoe 86 is attached to the valve rod 88a.
It is biased leftward by a spring 8E3c inserted between.

When the piston shaft 85 moves to the left in the figure, the shoe 86 connects the pump discharge bow bored in the distribution board 80) 8
The open end of the discharge passage 81b connected to 1a is liquid-tightly closed to block the flow of hydraulic oil from the discharge boat 81a to the first oil passage La (inner oil chamber). 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 disconnected from the pump cylinder 60. The motor cylinder 70 is mechanically driven through the motor.

The piston shaft 85 has a stepped diameter reduced diameter on its right side, and an oil chamber 87a is formed between the piston shaft 85 and the lid body 97, which is an inner member of a thrust needle bearing 98b that supports the main clutch valve body 95. There is. This oil chamber 87a is usually an oil passage 89a bored along the axial direction of the piston shaft 85.
and a valve rod 88 so as to communicate with the passage 89a.
the oil passage 89b bored in the center of the first
It communicates with oil passage La. And when the engine is running,
A portion of the high-pressure hydraulic oil circulating between the hydraulic pump P and the hydraulic motor M is constantly supplied to the oil chamber 87a through the series of passages.

Here, a female threaded portion 98 is formed on the inner periphery of the end portion of the main clutch valve body 95, and a male threaded portion 99 is formed on the outer periphery of the boss portion of the lid body 97.

By screwing these both threaded parts 98 and 99 together, the lid body 9
7 is integrally connected to the main clutch valve body 95. Therefore, the lid body 97 is always pressed against the thrust needle bearing 98b due to the high pressure oil constantly supplied to the oil chamber 87a, but the lid body 97 and the main clutch valve body 95
Since it is integrally connected to the main clutch valve body 9,
5 is also positioned in a state where it is biased to the right. Note that both the threaded portions 98 and 99 are screwed together liquid-tightly by applying a sealant in advance.

A piston portion 85 is provided at an axially intermediate portion of the piston shaft 85.
a is integrally formed, and an annular chamber 87b is formed 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 on the left side of the piston portion 85a. Furthermore, a dead end hole 88 is bored in the center of the piston shaft 85, and extends beyond the piston part 85a from the right end surface.
is formed. A through hole 8 bored in the piston shaft 85 in the radial direction is located between the blind hole 88 and the annular chamber 87b.
9c. Further, a through hole 89d is provided near the right end surface of the piston portion 85a to allow communication between the oil passage 89a and the dead hole 88.

Inside the blind hole 88 is a rod-shaped pilot spool 8.
4 has been inserted. A land portion 84a that fits into the inner peripheral surface of the dead hole 88 is provided at the tip of the pilot spool 84.
A small diameter portion 84b is formed on the right side of the land portion 84a with an appropriate axial dimension. Furthermore, a blind hole 88 is provided at the center of the pilot spool 84.
An atmospheric communication hole 89e is provided to communicate the inside with the atmosphere. The pilot spool 84 slides in the left-right direction by a link arm 46 that is attached to the outermost end of the pilot spool 84 via a pole gear 1 inward member 47. Note that a description of the operation of this link arm 46 will be omitted.

In the above configuration, the dimensions of each part are as shown in the shoe 86.
Pressure-receiving area of the end face: Cross-sectional area of the A piston portion 85a Pressure-receiving area of the inner end of the B piston shaft 85
:C The cross-sectional area of the diameter-reduced portion of the piston shaft 85 is determined so that the inequality A>(B-D)(B-D)>C is satisfied, where D is the cross-sectional area of the reduced diameter portion of the piston shaft 85.

Now, if you move the pilot spool 84 to the left,
Since the small diameter portion 84b of the pilot spool 84 is completely fitted into the dead end hole 88 inward from the right end surface of the piston portion 85a, the through hole 89d is blocked by the outer peripheral surface of the pilot spool 84, and the discharge boat 81a is closed. The high-pressure hydraulic oil flows into the oil chamber 87a through the oil passages 89a and 89b, and the oil pressure acts on the right end surface of the piston portion 85a, and also flows from the first oil path La side to the left end surface of the piston shaft 85. act. At this time, since the pressure receiving area of the right end surface of the piston portion 85a is ('B-D) and the pressure receiving area of the inner end surface of the piston shaft 85 is C, the above-mentioned inequality (B-D
)>C, the piston shaft 85 moves to the left. As the piston f[1186 moves, the shoe 8
6 is a discharge path 8 that communicates with the discharge port 81a of the distribution m80.
1b and closes it, and the hydraulic pump P
A state in which the motor is directly connected to the hydraulic motor M is realized.

In this state, the end face of the shoe 86 having the pressure receiving area A has high pressure hydraulic oil (oil chamber 8
7a) is applied, while the piston portion 85
There is an oil chamber 87a on the right end surface that grows the pressure receiving area CB-D).
The high-pressure hydraulic oil inside acts. By the way, since the two receiving areas are in the relationship of the above-mentioned inequality A>(B-D), a force is applied to the shoe 86 to move it to the right. If the shoe 86 moves even slightly to the right, the hydraulic pressure on the end surface of the shoe 86 is released, and the shoe 86 is pressed against the end surface of the distribution board 80 again.

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

Next, when the pilot spool 84 is moved to the right,
A small diameter portion 84b of the pilot spool 84 communicates with a through hole 89d formed in the piston shaft 85. This results in
High-pressure hydraulic oil acts not only on the right end surface of the piston portion 85a but also on the left end surface of the piston shaft 85, and also on the left end surface of the piston portion 85a through the through hole 88d1, the small diameter portion 84b1, the communication hole 89c, and the annular chamber 87b. It will work. Piston at this time? The pressure receiving area for moving the JJJ85 to the left is (B-D), whereas the pressure receiving area for moving the piston shaft 85 to the right is B, and since NB>(B-D), the piston shaft 85 moves to the right, and the direct connection between the hydraulic motor M and the hydraulic pump P is released. As can be seen from the above, when the pilot spool 84 is moved in the left-right direction, the piston shaft 85 is also moved in the left-right direction following this movement, and the direct coupling clutch valve DC is turned on and off.

This movement of the pilot valve 84 in the left and right direction is controlled by the pressure distribution panel 18.
This is done via a link mechanism 40 disposed on the side of the.

Therefore, this link mechanism 40 will be explained.

FIG. 5 shows this link mechanism 40, which includes a first shaft 42 having first and second rotating arms 42a, 42b, and a first shaft 42 below the first shaft 42. A second shaft 45 arranged in parallel is supported, and both shafts 42 and 45 have bearings 49a fixed to the case 5a.

It is rotatably supported by 49 b and 49 c.

Note that the first rotating arm 42a is connected to the pilot spool of the speed change servo unit 30 via the first link 41. Further, the second rotating arm 42b is actuated and rotated by a hydraulic cylinder or the like, and this rotation also causes the first rotating arm 42a to rotate, causing the pilot spool of the gear shifting servo unit 30 to move left and right. move it to

When this pilot spool is moved from side to side, the piston rod 33 is configured to follow and move, thereby controlling the swinging of the swash plate member 73 of the motor M.

A third rotating arm 46 is fixed to the second shaft 45, and this third rotating arm 46 is connected to the pilot valve 8 of the direct coupling clutch valve DC via a ballge e-ind member 47.
It is connected to 4. Therefore, when the third rotating arm 46 is rotated with the rotation of the second shaft 4S, the pilot valve 84 is moved left and right, and the direct coupling clutch valve DC is moved to zero.
N11OFF operation is performed. In addition, the third rotating arm 4
6 is a torsion coil spring 4 wound around the second shaft 45;
6a, the pilot valve 84 is always biased so as to be drawn outward (to the right).

On the other hand, driving and driven cams 43 and 44 that mesh with each other are fixedly installed on the first and second shafts 42 and 45, and the action of these cams 43 and 44 corresponds to the rotation of the first shaft 42. A certain degree of rotation is applied to the second shaft 45.

The operation of the cams 43, 44 will be explained based on FIGS. 6A to 6C. As shown in these figures, the drive cam 43 has a semicircular part 43a that has a semicircular arc centered on the first shaft 42, and a semicircular part 43a that partially protrudes outside the radius of the semicircle K43a. It consists of a convex portion 43b and a concave portion 43c partially sunk inward from the radius of the semicircular portion 43a, and is formed into a contour in which these three portions are smoothly connected. On the other hand, the driven cam 44 includes a semicircular portion 43a, an arcuate portion 44a consisting of a concave surface of curvature such as a path, and a semicircular portion 43a.
It consists of a straight portion 44b extending from a generally in the direction of the close battle.

First, the first rotating arm 42 is rotated by the second rotating arm 42b.
a is rotated counterclockwise, and accordingly, the inclination of the swash plate member 73 of the hydraulic motor M is maximized (at this time, the gear ratio is maximum) by the gear shifting servo unit 30, as shown in FIG. 6A. As shown in FIG.
a comes into contact with the arcuate portion 44a of the driven cam 44, and the drive cam 4
The convex portion 43b of No. 3 and the straight portion 44b of the driven cam 44 are separated from each other. Therefore, the third rotating arm 46 moves the pilot valve 84 to the right under the urging force of the torsion coil spring 48a, and the direct coupling clutch valve DC is in a fully open state.

From this state, when the second rotating arm 42b is rotated clockwise in order to reduce the inclination angle of the swash plate member 73, the first shaft 42 is rotated clockwise and the first servo unit 30 rotates the tilting arm 42b clockwise. The plate member 73 is rotated clockwise about the trunnion shaft 73a, its 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, and the straight portion 44b of the driven cam 44 is connected to the convex portion 4 of the driven cam 43.
3b is not rotated until it comes into contact, and accordingly, the pilot valve 84 is not moved either, and the direct coupling clutch valve DC is maintained in the fully open state.

The second @ moving arm 42b is further moved upward, and the swash plate member 7
3 becomes upright and the gear ratio becomes “1” (minimum),
As shown in FIG. 6B, the convex portion 43b of the drive cam 43 rotated clockwise together with the first shaft 42 comes into contact with the straight portion 44b of the driven cam 44. As shown in FIG.

When the second rotation 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 rotated.
is further moved to the right, but the motor trunnion 73
The stopper prevents further rotation and holds it in an upright position. However, since the first shaft 42 is rotated, the drive cam 43 is rotated clockwise, and as a result, the straight portion 44b is pushed by the convex portion 43b of the drive cam 43, as shown in FIG. 6C. , 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 biasing force of the torsion coil spring 48a, and as a result,
Pilot valve 84 is pushed to the left. This results in
As described above, the piston shaft 85 is moved to the left, and the shoe 86 closes the pump discharge passage 81b, resulting in a direct connection state (direct connection clutch valve D).
C ON state) is realized.

By the way, when the hydraulic pump P is driven, a part of high-pressure hydraulic oil is always supplied to the oil chamber 87a through the oil passages 89a and 89b, regardless of whether the direct coupling clutch valve DC is ON or OFF. Therefore, the lid body 97 is always pressed against the right thrust needle bearing 9θb. As described above, when the direct coupling clutch valve DC is switched from ON to OFF, high pressure oil flows into the annular chamber 87b by the right movement of the pilot spool 84, but at the initial stage of switching, the shoe 86 flows through the discharge passage 81b. Since it is still closed, the pressure inside the first oil passage La (inner oil chamber) is low. Therefore, due to the difference between the high pressure in the annular chamber 87b and the low pressure in the first oil passage La, a force acts on the main clutch valve body 95 to move it to the left.

However, as described above, the main clutch valve body 95
Since the lid body 97 is integrally connected with the screw portions 98 and 99, even if there is a difference in oil pressure as described above, the main clutch valve body 95 will move relative to the lid body 97 and will not separate. There's nothing to do. Therefore, the direct clutch valve DC
This prevents collision noise from occurring between the main clutch valve body 95 and the lid body 97 every time the main clutch valve body 95 is switched from ON to OFF.

In addition, in the above example, the lid body is screwed onto the main clutch valve body to integrally connect the two, but the connection method is not limited to this, and other connection methods may also be used. Of course it's good.

According to the present invention, the lid body for forming the hydraulic oil chamber between the direct coupling clutch piston shaft and the main clutch valve body is integrally connected to the other end of the main clutch valve body. Because
Even if there is a difference in the hydraulic pressure applied to the main clutch valve body when the direct coupling clutch piston shaft is moved to release the hydraulic closed circuit, the main clutch valve body will not move relative to the lid body. It can be prevented. Therefore, it is possible to prevent collision noise between the main clutch valve body and the lid body, and it is possible to obtain a hydraulic continuously variable transmission that does not generate abnormal noise.

[Brief explanation of drawings]

Fig. 1 is a hydraulic circuit diagram of a hydraulic continuously variable transmission to which the present invention is applied, Fig. 2 is a sectional view of the above continuously variable transmission, and Figs. 3 and 4 are hydraulic clutch devices of the above continuously variable transmission. 5 is a perspective view showing a link mechanism for controlling the operation of the direct coupling clutch valve; FIGS. 6A to 6C are front views showing the operation of the cam that constitutes the link mechanism; FIG. 7 is a sectional view showing a conventional hydraulic clutch device. 4... Shuttle valve 20... Forward/forward switching device 30... Servo unit for speed change 60... Pump-and-linda 70... Motor cylinder 80... Distribution panel 84... Pilot spool 92...・Distribution ring 95...Main clutch valve body 97...Lid body P...Hydraulic pump M・
...Hydraulic motor CL...Main clutch valve DC
・・・Direct clutch valve

Claims (1)

[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, and the hydraulic motor is driven by hydraulic pressure from the hydraulic pump. The hydraulic continuously variable transmission includes: a hollow cylindrical member formed integrally with the cylinder of the hydraulic motor; and a hollow cylindrical member formed integrally with the cylinder on one end side of the cylindrical member, communicating with the hydraulic pump and the hydraulic motor. a distribution board provided with an oil passage for the cylindrical member; a hollow fixed shaft inserted into the cylindrical member; and a hollow fixed shaft inserted into the fixed shaft so as to be rotatable about its axis; A cylindrical main clutch valve body that controls the degree of communication between the outer space and the inner space in the hydraulic closed circuit composed of a space outside the shaft and a space inside the shaft; A direct coupling clutch piston shaft which is movably slid together and which, through this movement, closes the oil passage of the distribution board at one end to control the on/off of the hydraulic closed circuit, and a direct coupling clutch piston shaft which faces the other end of the main clutch valve body. and a lid body arranged to form a hydraulic oil chamber between the direct coupling clutch piston shaft, and the lid body is integrally connected to the other end of the main clutch. Hydraulic clutch device for gear transmission.