JPS63130959A - Hydraulic transmission device - Google Patents

Abstract

PURPOSE:To smooth oil circulation in an oiltight chamber by interposing No.1 pressure control valve, which opens under the oil pressure in the oiltight chamber, between the oiltight chamber and a lubricating chamber, moreover interposing No.2 pressure control valve between the secondary side of the No.1 pressure control valve and a tank. CONSTITUTION:On the way of a supply passage 51 connecting an oiltight chamber 31 to a lubricating chamber 75, there is interposed No.1 pressure control valve 50 which opens under the oil pressure in the oiltight chamber 31. Between a tank T and the supply passage 51, which connects the No.1 pressure control valve 50 to the lubricating chamber 75, there is interposed No.2 pressure control valve 50' which opens under oil pressure lower than the set value of the No.1 pressure control valve 50. Thereby, even if a hydraulic motor M or a hydraulic pump P operates at high speed or high load so that the oil pressure in the lubricating chamber 75 increases, the operation of the No.1 pressure control valve 50 can be kept normal, accordingly, oil circulation in the oiltight chamber 31 becomes smooth so as to avoid increase of oil temperature, thereby rendering it possible to prevent durability of the hydraulic pump P and the hydraulic motor M from lowering.

Description

Detailed Description of the Invention A0 Object of the Invention (1) Industrial Application Field The present invention relates to a sliding surface between a large number of pump plungers slidably connected to a pump cylinder and a pump swash plate that receives the pump plungers. This is applied to the sliding surface between the hydraulic pump, which is supplied with oil in the pump cylinder to lubricate the motor cylinder, and the motor swash plate that receives the motor plungers and the motor plungers that slide on the motor cylinder. The hydraulic motor, to which oil in the motor cylinder is supplied for lubrication, is connected to form a hydraulic closed circuit, and a lubrication chamber is provided to surround the sliding surface between the swash plate and the plunger in one of the hydraulic pump and the hydraulic motor. The present invention relates to a hydraulic transmission device in which the other of a hydraulic pump and a hydraulic motor is surrounded by an oil-tight chamber communicating with a sliding portion thereof.

(2) Conventional technology Conventionally, in a swash plate type hydraulic motor or a swash plate type hydraulic pump, it is not possible to provide a lubrication chamber that surrounds the sliding surface between the swash plate and the plunger in order to lubricate the sliding surface between the swash plate and the plunger. 61-11856
This is known from Publication No. 6.

When this technique is applied to a hydraulic motor of a hydraulic transmission device such as that disclosed in Japanese Patent Application Laid-Open No. 57-76357, oil released from a pressure control valve that regulates the pressure in an oil-tight chamber surrounding a hydraulic pump is used. It is conceivable to supply the oil to the lubrication chamber of the hydraulic motor.

(3) Problems to be solved by the invention However, as mentioned above, when the oil relieved from the pressure control valve is supplied to the lubrication chamber, the amount of oil leaked from the sliding surface between the swash plate and the plunger at high speeds or high loads. When the oil pressure increases, the oil pressure in the lubrication chamber increases, and in some cases, the oil pressure in the lubrication chamber becomes higher than the set oil pressure of the pressure control valve, causing the pressure control valve to not operate normally. arise. When such a phenomenon occurs, the oil cannot be circulated smoothly in the oil-tight chamber, and the oil temperature may rise above an appropriate value, which may reduce the durability of the hydraulic pump.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a hydraulic transmission device that can smoothly circulate oil in an oil-tight chamber.

B0 Structure of the Invention (1) Means for Solving the Problems According to the present invention, in order to guide the oil in the oil-tight chamber to the lubrication chamber, there is a hydraulic pressure in the oil-tight chamber in the middle of the supply passage connecting the oil-tight chamber and the lubrication chamber. A first pressure control valve that opens when exceeds a set value is provided in the supply passage between the first pressure control valve and the lubrication chamber, and is opened at a hydraulic pressure lower than the set value of the first pressure control valve. A second pressure control valve is connected for valving and releasing hydraulic pressure.

(2) Effect According to the above configuration, when the oil pressure in the lubrication chamber increases and exceeds the set value of the second pressure control valve, the second pressure control valve opens;
Since the set value of this second pressure control valve is lower than the set value of the first pressure control valve, the oil pressure in the lubrication chamber does not exceed the set value of the first pressure control valve, and the circulation of oil in the oil-tight chamber is prevented. It will be done smoothly.

(3) Embodiment Hereinafter, an embodiment in which the present invention is applied to a hydraulic continuously variable transmission for a vehicle will be explained with reference to the drawings. First, in FIG. The step-change transmission CVT includes a constant discharge type hydraulic pump P connected to an input shaft 2 driven by the engine, and the hydraulic pump P.
and a variable displacement hydraulic motor M disposed on the same axis constitute a hydraulic closed circuit C (connected to each other. 1
8 and is connected to the wheels W via a differential gear.

The hydraulic closed circuit C includes a high-pressure oil passage ch that connects the discharge port of the hydraulic pump P and the suction port of the hydraulic motor M, and a low-pressure oil passage C1 that connects the discharge port of the hydraulic motor M and the suction port of the hydraulic pump P. Equipped with. High pressure oil line ch and low pressure oil line C
Z is connected via clutch valve 116. In addition, the discharge port of the replenishment pump F driven by the input shaft 2 is the replenishment oil path 1.
37 and check valves 138, 138 to the high-pressure and low-pressure oil passages ch and CG, and the hydraulic oil pumped up from the oil tank T replenishes the shortage (hydraulic closed circuit is connected via the replenishment oil passage 137). C.

Furthermore, a relief valve 150 that opens when the oil pressure in the replenishment oil passage 137 exceeds a set value is connected in the middle of the replenishment oil passage 137 in order to keep the discharge pressure of the replenishment pump F constant. Further, the hydraulic pump P is surrounded by an oil-tight chamber 31 communicating with its sliding portion, and this oil-tight chamber 31 is connected to a lubrication chamber 75 provided in the hydraulic motor M via a first pressure control valve 50. A second pressure control valve 50', which opens at a pressure lower than that of the first pressure control valve 50, is connected between the first pressure control valve 50 and the lubricating chamber 75.

The clutch valve 116 is connected to high pressure and low pressure oil passages Ch.

It is a throttle valve that has an intermediate position and switches between an opening that short-circuits between C1 and an opening that cuts off between both oil passages ch:c1, and when the clutch valve 116 is in short-circuit operation, the hydraulic motor M Since hydraulic oil is not supplied to the hydraulic motor M, the hydraulic motor M is in a neutral state in which it is inactive. Further, when the clutch valve 116 is in the closing operation, the hydraulic oil circulates between the hydraulic pump P and the hydraulic motor M, so that driving force is transmitted and the vehicle is in a running state.

Furthermore, when the opening degree of the clutch valve 1160 reaches an intermediate position, circulation of hydraulic oil occurs in accordance with the opening degree, resulting in a half-clutch state.

In FIG. 2, to explain the specific structure of the continuously variable transmission CVT, the continuously variable transmission CVT consists of two case halves 1
It is housed in a mission case 1 which is made up of a combination of a and lb.

The hydraulic pump P includes a pump cylinder 4 connected to an input shaft 2 by a spline 3, and a plurality of cylinder holes 5, 5, . A large number of plungers 6 that are slid together
．． 6... is provided. Power from the engine E is transmitted to the input shaft 2 via the flywheel 7.

On the other hand, the hydraulic motor M includes a motor cylinder 8 disposed so as to concentrically surround the pump cylinder 4 of the hydraulic pump P and rotate relative thereto;
is provided with a large number of motor plungers 10, 10, .

An output shaft 11 is coaxially protruded from one end of the motor cylinder 8 in the axial direction, and a support shaft 12 is coaxially protruded from the other end. The output shaft 11 is connected to the end wall of one case half 1a via a needle bearing 13, and the support shaft 12 is connected to the ball bearing 1.
4 to the end wall of the other case half 1b.

The input shaft 2 passes through the end wall of one case half 1a in an oil-tight manner and is disposed concentrically within the output shaft 11.

Moreover, a plurality of needle bearings 15 are interposed between the inner surface of the output shaft 116 and the outer surface of the input shaft 2, so that the input shaft 2 and pump cylinder 4 and the output shaft 11 and motor cylinder 8 rotate relative to each other. It is possible.

A forward and reverse gear device G is provided between the output shaft 11 and a subshaft 18 which is parallel to the output shaft 11 and rotatably supported on both end walls of the mission case 1 via a roller bearing 16 and a ball bearing 17. is provided.

The front and reverse gear device G includes a pair of drive gears 19 and 20 fixed to the output shaft 11, and a driven gear 21 that meshes with one of the drive gears 19 and is rotatably supported on the subshaft 18.
A driven gear 22 rotatably supported on the subshaft 18 in correspondence with the other driving gear 20, an intermediate gear 23 meshing with the driving gear 20 and the driven gear 22, and both driven gears 21, 22.
A driven clutch toothed wheel 24 is fixed to the subshaft 18 between driving clutch toothed wheels 21a and 228, which are integrally provided at opposing portions of the driven clutch toothed wheel 24 and redrive clutch members 21a and 22a. A shift fork 26 is engaged with the clutch member 25 to selectively operate the clutch member 25.

A gear 28 that meshes with an input gear 27 of the differential is integrally provided on the countershaft 18, and the differential switches between the forward and reverse directions of the vehicle in response to the operation of the clutch member 25. It is driven by

In FIG. 3, an oil-tight chamber 31 is defined between the motor cylinder 8 and the pump cylinder 4 of the hydraulic pump P.
A swash plate 32 facing the end face of the pump cylinder 4 is supported inside the motor cylinder 8 within the oil-tight chamber 31 . An annular integral shoe 33 is in sliding contact with the swash plate 32 .

Each plunger 6.6... and the shoe 33 are connected to each other via a connecting rod 44 so as to be able to freely swing.
A presser ring 34 supported by the motor cylinder 8 is in contact with the inner step of the motor cylinder 8 via a roller bearing 42, and the presser ring 34 has a ring 34 that allows movement in the axial direction and prevents relative rotation. (Input shaft 2 via spline 36
A spring holder 35 connected to the spring holder 35 abuts. A coil spring 37 surrounding the input shaft 2 is interposed between the spring holder 35 and the pump cylinder 4.
7, the spring holder 35 elastically presses the shoe 33 toward the swash plate 32 via the presser ring 34. Moreover, the spring holder 35 and the presser ring 34 are in contact with each other on a spherical surface, and the spring holder 35 evenly contacts the presser ring 34 to transmit the elastic force of the coil spring 37 to the presser ring 34.

The oil-tight chamber 31 is divided by the shoe 33, the presser ring 34, and the spring holder 35 into a first chamber 31a on the swash plate 32 side and a second chamber 31b on the pump cylinder 4 side.

The inner peripheral side of the sliding surface of the swash plate 32 and the shoe 33 faces the first chamber 31a, and lubricating oil leaking from the sliding surface flows into the first chamber 3La. Incidentally, in order to achieve lubrication between the swash plate 32 and the shoe 33, an annular hydraulic pocket 38 is provided on the front surface of the shoe 33. Via provided oil holes 39, 40, 41, it communicates with a pump chamber 45 defined between each plunger 6 and the pump cylinder 4. Therefore, the pressure oil in the pump chamber 45 passes through the oil holes 41 and 40.39 to the hydraulic pocket 3.
8. As a result, the shoe 33 and the swash plate 3
2 sliding surfaces are lubricated.

Moreover, at the same time, the hydraulic pressure in the hydraulic pocket 38 exerts pressure on the shoe 33 so as to receive the thrust of the plunger 6, thereby reducing the contact pressure between the shoe 33 and the swash plate 32.

On the other hand, the motor cylinder 8, the swash plate 32, the shoe 33 are
An annular lubrication chamber 43 surrounding the sliding surface is defined by the roller bearing 42, and this lubrication chamber 43 constitutes a part of the second chamber 31b.

Pressure oil in the hydraulic nozzle 38 is constantly leaking into the lubrication chamber 43 through the sliding surface between the shoe 33 and the swash plate 32, and after the leaked oil fills the lubrication chamber 43, it passes through the roller bearing 42. It flows to the second chamber 31b side. Therefore, new lubricating oil is always kept in the lubricating chamber 43, and the sliding surfaces of the shoe 33 and the swash plate 32 can be reliably lubricated from the outside of the shoe 33 with this oil.

In addition to the oil from the lubrication chamber 43, leaked oil from the sliding surfaces of the plunger 6 and the cylinder hole 5, as well as the sliding surfaces of the pump cylinder 4 and the distribution board 46 flows into the second chamber 31b.

The spring holder 35 has a first chamber 31a and a second chamber 31b.
A communication path 47 is provided to communicate between the two.

Further, a first supply passage 48 communicating with the first chamber 31a is formed between the output shaft 11 and the input shaft 2 of the motor cylinder 8, and this first supply passage 48 is connected to a second supply passage 49, a first pressure It is connected to a lubrication chamber 75 provided in the hydraulic motor M via the control valve 50 and the third supply passage 51 .

In FIG. 4, the first pressure control valve 50 includes a bottomed cylindrical spool valve body 52 for switching communication and isolation between the second and third supply passages 49,51, and the spool valve body 52.
and a spring 53 that biases the switch in the blocking direction. An input shaft 2 is attached to the end wall of the case half 1a in the mission case 1.
A bottomed hole 54 is bored parallel to the spool valve body 5.
2 is available.

An oil chamber 55 is defined between the closed end of the bottom hole 54 and the bottomed hole 5.
4. Further, a support member 57 whose movement toward the open end of the bottomed hole 54 is regulated by a retaining ring 56 fitted in the middle of the bottomed hole 54 is inserted into the bottomed hole 54. A spring 53 is interposed between the spool valve body 52 and the spool valve body 52 . Therefore, the spool valve body 52 slides due to the balance between the force in the valve opening direction due to the oil pressure in the oil chamber 55 and the force in the valve closing direction due to the spring 53.

The oil chamber 55 includes a second hole bored in the end wall of the case half 1a.
A supply passage 49 is communicated. Further, an annular groove 58 is provided in the middle of the bottomed hole 54, and the state of communication with the oil chamber 55 is switched between the state of communication and the cutoff state by the spool valve body 52. is communicated with the annular groove 58.

Therefore, the first pressure control well 50 opens when the oil pressure in the oil chamber 55, that is, the oil pressure in the oil-tight chamber 31 becomes larger than the value set by the spring 53, and regulates the oil pressure in the oil-tight chamber 31 to a predetermined value.

At the opposite ends of the pump cylinder 4 and the shoe 33, mutually meshing bevel gears 61, 62 are fixed. These bevel gears 61 and 62 are formed into synchronous gears with the same number of teeth, and when the pump cylinder 4 rotates together with the input shaft 2, the shoe 33 rotates synchronously via the bevel gears 61 and 62. Driven. As a result, the plunger 6 running on the upward side of the slope of the swash plate 32 is given a discharge stroke from the swash plate 32 via the connecting rod 44, and the plunger 6 running on the downward side of the slope is given a suction stroke. It will be done.

In the hydraulic motor M, the annular motor swash plate 63 facing the motor cylinder 8 is connected to the annular swash plate holder 6.
4 is fitted. This swash plate holder 64 is integrally equipped with a pair of trunnion shafts 65 that protrude outward from both sides thereof.
Those trunnion shafts 65 are pivotally supported by the mission case l. Therefore, the motor swash plate 63 can tilt around the axis of the trunnion shaft 65 together with the swash plate holder 64.

The tip of each motor plunger 10 is swingably connected to a plurality of motor shoes 66 that are in sliding contact with a motor swash plate 63. Moreover, in order to keep each motor shoe 66 in sliding contact with the motor swash plate 63, a presser plate 67 that presses the back surface of each motor shoe 66 is rotatable by a ring 69 fixed to the swash plate holder 64 with bolts 68. Supported by The connecting portion between each motor shoe 66 and each motor plunger lO passes through the presser plate 67 at multiple positions in the circumferential direction,
Therefore, the holding plate 67 rotates together with the motor shoe 66.

Each motor shoe 66 is provided with a hydraulic pocket 70 on the front surface that slides into contact with the motor swash plate 63.

On the other hand, the closed end of each cylinder hole 9 and each motor plunger 1
A hydraulic chamber 71 defined between the motor plunger 10 and a series of oil holes 7 formed in the motor shoe 66
2.73 to the hydraulic pocket 70. Therefore, the pressure oil in the hydraulic chamber 71 is supplied to the hydraulic pocket 70 through the oil holes 72 and 73, and exerts pressure on the motor shoe 66 so as to receive the protruding thrust of the motor plunger 10.

As a result, the contact pressure between the motor shoe 66 and the motor swash plate 63 is reduced, and the sliding surfaces of the motor shoe 66 and the motor swash plate 63 are lubricated.

A cylindrical partition body 74 is fitted onto the inner circumferential surface of the swash plate holder 64 and faces the inner circumferential surface of the presser plate 67 with a small gap.
A lubrication chamber 75 surrounding the sliding surfaces of the motor shoe 66 and the motor swash plate 63 is defined by the partition wall 74, the swash plate holder 64, and the presser plate 67.

Therefore, the pressure oil in each hydraulic pocket 70 constantly leaks through the sliding surfaces of the motor shoe 66 and the motor swash plate 63, and the leaked oil fills the lubrication chamber 75 as lubricating oil and then passes through the presser plate. It leaks from the gaps in various parts around 67. Therefore, new lubricating oil is always kept in the lubricating chamber 75, and the oil is used to make the motor shoe 66 and the motor swash plate 6.
3 can be reliably lubricated from the outside of the motor shoe 66.

Moreover, the third supply passage 51 is communicated with the lubricating chamber 75, and when the first pressure control valve 50 is opened, the oil-tight chamber 31 is connected to the lubricating chamber 75.
The oil flowing out is supplied to the lubrication chamber 75, and thereby the sliding surfaces of the motor shoe 66 and the motor swash plate 63 can be reliably lubricated.

Further, in the middle of the third supply passage 51, a first pressure control valve 50 is provided.
A second pressure control valve 50' having basically the same configuration as the first pressure control valve 50 is connected, and the second pressure control valve 50' opens at a set oil pressure lower than that of the first pressure control valve 50, and opens the third supply passage. 51 is led to oil tank T.

A servo motor 81 is provided in the mission case 1 to tilt and drive the swash plate holder 64, that is, the motor swash plate 63. This servo motor 81 includes a servo cylinder 82 fixed to the mission case 1, and a servo piston 85 that slides on the servo cylinder 82 to partition the inside of the servo cylinder 82 into a left oil chamber 83 and a right oil chamber 84.
The left oil chamber 8 is provided integrally with the servo piston 85.
A piston rod 86 that oil-tightly and movably penetrates the end wall of the servo cylinder 82 on the third side, and a servo piston 85.
The tip of the piston rod 86 is slid into the valve hole 87 formed in the piston rod 86, and the right oil chamber 8 of the servo cylinder 82
A piston rod 86 configured with a pilot valve 88 that oil-tightly and movably penetrates the end wall on the 4th side is connected to the swash plate holder 6 via a pin 89.
4. Further, an oil passage 90 provided in the servo cylinder 82 is always in communication with the left oil chamber 83, and hydraulic pressure supplied from this oil passage 90 acts on the servo piston 85. The right oil chamber 84 is connected to the valve hole 8 in the servo piston 85 and the piston rod 86 in response to the rightward movement of the pilot valve 88.
7, and a passage 9 that communicates the right oil chamber 84 with the left oil chamber 83 in response to leftward movement of the pilot valve 88.
2 are drilled. Roughly speaking, the valve hole 87 communicates with the oil tank T at the bottom of the mission case 1 via a reflux path 93 .

The servo piston 85 is amplified by the hydraulic pressure supplied from the oil passage 9o so as to follow the leftward and rightward movements of the pilot valve 88, thereby moving the swash plate holder 64, that is, the motor swash plate 63 to the maximum tilt position shown in the figure. and a perpendicular position perpendicular to each motor plunger 1o. At this time, the motor swash plate 63 gives reciprocating motion to each motor plunger 10 as the motor cylinder 8 rotates, causing the motor plungers 10 to repeatedly expand and contract. It is adjusted steplessly.

A hydraulic closed circuit C is formed between the hydraulic pump P and the hydraulic motor M via a distribution panel 46 and a distribution ring 97. When the pump cylinder 4 is rotated by the input shaft 2, the high-pressure hydraulic oil discharged from the pump chamber 45 of the cylinder 5 that accommodates the plunger 6 on the discharge stroke flows into the cylinder hole that accommodates the motor plunger IO on the expansion stroke. 9 is fed to the hydraulic chamber 71. On the other hand, the hydraulic oil discharged from the hydraulic chamber 71 of the cylinder hole 9 that accommodates the motor plunger IO in the contraction stroke returns to the pump chamber 45 of the cylinder hole 5 that accommodates the plunger 6 in the suction stroke. During this time, the motor cylinder 8, that is, the support shaft 11 is Rotationally driven.

In this case, the motor cylinder 8 relative to the pump cylinder 4
The gear ratio of is given by the following equation.

As is clear from this equation, if the capacity of the hydraulic motor M determined by the stroke of the motor plunger 10 is changed to a value of zero, the gear ratio can be increased to the required value of 1. It can be changed.

The motor cylinder 8 is composed of first to fourth parts 8a to 8d divided in the axial direction. The first portion 8a includes
The output shaft 11 is integrally provided, and the swash plate 32 is provided on the first portion 8a. Also, the second third and fourth portions 8b
A cylinder hole 9 is provided at ~8d. The third portion 8c constitutes a distribution board 46, and the fourth portion 8d is integrally provided with a support shaft 12.

The first and second parts 8a, 8b are connected by a plurality of bolts 98, and the second. The third and fourth portions 8b to 8d are integrally connected by a plurality of pins 101 with dowel pins 99.degree. 100 inserted into their respective joints and positioned relative to each other.

The inner end of the input shaft 2 is supported at the center of the distribution board 46 via a needle bearing 105, and is connected to the pump cylinder 4.
The spring 37 brings the spring 37 into elastic sliding contact with the distribution board 46 .

A bolt 10 is installed on the outer surface side of the end wall of the case half 1b.
6, a support plate 107 is fixed, and a cylindrical fixed shaft 108 that protrudes into the support shaft 12 of the motor cylinder 8 is fixedly connected to the support plate 107. At the inner end of this fixed shaft 108 is a distribution ring 97 that slides into contact with the distribution panel 46.
is eccentrically supported, and the hollow portion 10 provided in the fourth portion 8d of the motor cylinder 8 is
9 is divided into an inner chamber 110 and an outer chamber 111.

On the other hand, the distribution board 46 has a discharge and suction boat 112.1.
13 is bored, and its discharge boat 112 connects the pump chamber 45 and inner chamber 11 of the plunger 6 in the discharge stroke.
0, and the pump chamber 45 of the plunger 6 in the suction stroke communicates with the outer chamber 111 through the suction port 113. In addition, the distribution board 46 includes a large number of communication boats 114,
114... are drilled, and these communication ports 1
Each hydraulic chamber 71 of the motor cylinder 8 is communicated with the inner chamber 110 or the outer chamber 111 by 14° 114 .

Therefore, when the pump cylinder 4 rotates, the high-pressure hydraulic oil generated by the discharge stroke of the plunger 6 flows from the discharge boat 112 into the inner chamber 110, and further passes through the communication port 114 communicating with the inner chamber 110 during the expansion stroke. The oil flows into the hydraulic chamber 71 of the motor plunger lO to apply thrust to the motor plunger lO. On the other hand, the hydraulic oil discharged by the motor plunger 10 in the contraction stroke is returned to the pump chamber 45 of the plunger 6 in the suction stroke via the communication boat 114 and the suction boat 113 that communicate with the outer chamber 111. By circulating the hydraulic oil, power is transmitted from the hydraulic pump P to the hydraulic motor M as described above.

The side wall of the fixed shaft 108 has an inner chamber 110 and an outer chamber 1.
For example, two short-circuit ports 115 that can communicate between the two short-circuit ports 115 are bored, and a cylindrical clutch valve 116 that opens and closes these short-circuit ports 115 is rotatably fitted into the fixed shaft 108. This clutch valve 116 has a valve hole 117 corresponding to the short-circuit port 115 on its side wall near its tip, and an operation connection part 119 connected to an operation shaft 118 connected to a clutch control device (not shown) at its base end. It will be done.

When the clutch valve 116 is rotated to align the valve hole 117 with the shorting port 115 and fully opened, the clutch is off, and when the valve hole 117 is moved from the shorting port 115 and fully closed, the clutch is on, and the valve hole 117 and When the shorting port 115 is slightly shifted to a half-open state, a half-clutch state is obtained. That is, in the clutch-off state, the hydraulic oil discharged from the discharge boat 112 into the inner chamber 110 is immediately short-circuited to the outer chamber 11 and the suction port 113 through the short-circuit port 115, causing the hydraulic motor M to become inoperable, and in the clutch-on state. In this case, the short circuit of the hydraulic oil as described above is prevented, and the hydraulic oil is connected from the hydraulic pump P to the hydraulic motor M.
Circulation of hydraulic oil occurs and normal transmission occurs.

The clutch valve 116 has a built-in hydraulic servo motor 121 operated by a pilot valve 120 , and a valve rod 123 having a smaller diameter than the inner diameter of the clutch valve 116 is provided at the tip of the servo piston 122 . This excuse 123
protrudes into the inner chamber 110, and a closure valve 124 for the discharge boat 112 is swingably attached to the tip thereof. By moving the servo piston 122 to the left, the discharge boat 112 can be closed by bringing the closing valve 124 into close contact with the distribution board 46. This closing is performed when the motor swash plate 73 is placed in an upright position and the gear ratio is set to 1. This causes the plunger 6 to be hydraulically locked and the air to be removed from the pump cylinder 4 via each plunger 6 and the swash plate 32 to be closed. The motor cylinder 8 can be mechanically driven, and as a result, the thrust of the motor plunger 10 against the motor swash plate 63 disappears, and the loads on the various bearings due to the thrust are removed.

The fixed shaft 108 and the support plate 107 have an oil passage 139 communicating with the inner chamber 11O and an oil passage 14 communicating with the outer chamber 111.
0 is punctured. Further, an oil passage 141 communicating with an oil passage 90 connected to the servo motor 81 is bored in the support plate 107, and the oil passage 141 and the above-mentioned both ground passages 139.
A switching valve 142 that selectively switches the state of communication with 0 is provided.

This switching valve 142 operates to connect the higher oil pressure of the two-way passages 139 and 140 to the oil passage 141. Therefore, the servo motor 81 for tilting the motor swash plate 63 of the hydraulic motor M has an inner chamber 110 and an outer chamber 11.
Hydraulic pressure will be supplied from the side with the higher oil pressure.

Pilot valve 88.12 for both servo motors 81.121
0, one ends of links 127 and 128 are connected, and the other end of link 127 is interlocked and connected to a rotation shaft 129 that is rotated by an operation means (not shown). Also, rotation axis 1
29 is provided with a cam 130, and the link 128
A cam follower 131 that comes into sliding contact with the cam 130 is provided at the other end.

As a result, when the servo motor 81 is operated to bring the motor swash plate 63 into the upright state, the servo motor 121
operates to close the discharge port 112 with the closure valve 124 .

A replenishment pump F is provided on the outside of the end wall of the case half 1a.
will be equipped. This replenishment pump F is driven by the input shaft 2, and pumps up oil from an oil tank T at the bottom inside the mission case l.

The discharge port 136 of this replenishment pump F is connected to the input shaft 2.
The supply oil passage 13 communicates with the supply oil passage 137 provided within the
7 communicates with the inner chamber 110 via a check valve 138, and communicates with the outer chamber 111 via a check valve (not shown). Therefore, when hydraulic oil leaks from the hydraulic closed circuit C between the hydraulic pump P and the hydraulic motor M, the leakage can be automatically replenished from the replenishment pump F.

In FIG. 5, the oil passage 15 communicating with the discharge port 136
1 and an oil passage 152 communicating with the oil tank T are bored in the end wall of the case half 1a, and a relief valve 150 is interposed between the two ground passages 151 and 152.

The relief valve 150 includes a bottomed cylindrical spool valve element 153 for switching between communication and isolation between the oil passages 151 and 152, and a spring 1 that biases the spool valve element 153 in the blocking direction.
54. A bottomed hole 155 is formed in the end wall of the case half 1a, and the spool valve body 153 defines an oil chamber 156 on the closed end side of the bottomed hole 155. It is slid into the hole 155. Further, a support member 158 whose movement toward the open end of the bottomed hole 155 is regulated by a retaining ring 157 fitted in the middle of the bottomed hole 155 is attached to the bottomed hole 155.
5, and a spring 154 is interposed between this support member 158 and the spool valve body 153. Therefore, the spool valve body 153 slides due to the balance between the force in the valve opening direction due to the oil pressure in the oil chamber 156 and the force in the valve closing direction due to the spring 154.

An oil passage 151 is communicated with the oil chamber 156 . Also, bottomed hole 1
An annular groove 159 is provided in the middle of the oil chamber 156 and is switched between communication and isolation with the spool valve body 153, and the oil passage 152 communicates with the annular groove 159.

The relief valve 150 opens when the oil chamber 156, that is, the discharge oil pressure of the replenishment pump F becomes larger than the value set by the spring 154, and regulates the discharge oil pressure of the replenishment bomb F to a constant pressure.

Next, the operation of this embodiment will be explained. The oil-tight chamber 3 defined between the pump cylinder 4 and the motor cylinder 8
The second chamber 31b in 1 includes a shoe 33 and a swash plate 3.
Most of the oil leaked from the sliding surface of pump cylinder 4.
Leakage oil from the sliding surfaces of the distribution board 46 and leakage oil from the sliding surfaces of the plunger 6 and the cylinder hole 5 are guided. Residual leakage oil from the sliding surfaces of the shoe 33 and the swash plate 32 is guided to the first chamber 31a, which communicates with the second chamber 31b via a communication path 47. The leaked oil sealed in the oil-tight chamber 31 is supplied to the lubrication chamber 75 through each supply passage 48, 49, 51 in response to the opening of the pressure control valve 5o.

By the way, assume that the hydraulic motor M rotates at a high speed or has a high load, and the amount of oil leaking from each sliding contact portion increases.

In this case, when the oil pressure in the lubrication chamber 75, that is, the third supply passage 51 increases in response to an increase in the amount of leaked oil, when the oil pressure exceeds the set value of the second pressure control valve 50', the second pressure control valve 50' When the valve 50' is opened, the oil in the third supply passage 51 is discharged.

Moreover, since the set value of the second pressure control valve 50' is set smaller than the set value of the first pressure control valve 50, the hydraulic pressure in the lubrication chamber 75 (larger than the set value of the first pressure control valve 50) Therefore, the operation of the first pressure control valve 50 can be maintained normally, and the oil in the oil-tight chamber 31 can be smoothly circulated.

In the above embodiment, the relief valve 150 and both pressure control valves 50 and 50' were provided on the end wall of the case half-closed 1a.
Answer 150.50.50' separate from case half 1a
may be attached to the case half 1a.

6, 7 and 8 show other embodiments of the present invention, in which oil in the third supply passage 51 flows into the case half 1a when the second pressure control valve 50' is opened. Oil passage 161 provided
The oil is then guided to an oil reservoir 160 provided at the end of the subshaft 18. In this way, the roller bearing 16 that supports the subshaft 18 and the front.

The lubrication of the reverse gear device G can be enhanced.

In addition, a relief valve 150' for keeping the discharge oil pressure of the replenishment pump P constant is connected to the replenishment oil passage 137 and connected to the distribution panel 46.
It is provided between an oil passage 151' bored in the oil-tight chamber 31 and an oil passage 152' bored in the distribution board 46 and communicating with the oil-tight chamber 31.

This relief valve 150' has basically the same configuration as the relief valve 150 of the above-described embodiment, and opens when the oil pressure in the replenishment oil passage 137 exceeds a set value. Replenish lubricant.

Therefore, the oil-tight chamber 31 is sufficiently replenished with oil.

Moreover, the set pressure of the first pressure control valve 50 is the same as that of the relief valve 150.
The hydraulic pressure in the oil-tight chamber 31 never becomes higher than the set value of the relief valve 150', and the operation of the relief valve 150' can always be maintained normally.

C1 Effects of the invention As described above, according to the present invention, the oil in the oil-tight chamber is guided to the lubrication chamber (in order to prevent oil pressure in the oil-tight chamber from exceeding a set value) A first pressure control valve that opens at certain times is interposed, and the supply passage between the first pressure control valve and the lubrication chamber opens at a hydraulic pressure lower than the set value of the first pressure control valve to release hydraulic pressure. Since the second pressure control valve is connected to the lubrication chamber, even when the oil pressure in the lubrication chamber increases due to the high speed or high load of the hydraulic motor or hydraulic pump, the operation of the first pressure control valve is maintained normally, and the oil tight chamber is maintained. It is possible to prevent oil temperature from rising by smoothly circulating the oil in the oil tank, thereby preventing a decrease in the durability of the hydraulic bomb or hydraulic motor.

[Brief explanation of the drawing]

Figures 1 to 5 show one embodiment of the present invention.
The figure is a hydraulic circuit diagram of a hydraulic continuously variable transmission for vehicles, Figure 2 is an overall longitudinal side view showing the concrete structure of the continuously variable transmission, Figure 3 is an enlarged view of the main parts of Figure 2, and Figure 4 5 is an enlarged view of the section v in FIG. 2, FIGS. 6 to 8 show other embodiments of the present invention, and FIG. A hydraulic circuit diagram corresponding to the figure, Fig. 7 is a vertical side view corresponding to Fig. 2,
FIG. 8 is an enlarged view of the main part corresponding to FIG. 3. 31... Oil tight chamber, 48.49.51... Supply passage,
50... First pressure control valve, 50'... Second pressure control valve, 75... Lubrication chamber, C... Hydraulic closed circuit, M... Hydraulic motor, P... Hydraulic pump No. Figure 4

Claims (1)

[Claims] A hydraulic pump, in which oil in the pump cylinder is supplied to lubricate the sliding surfaces between a large number of pump plungers slidingly connected to the pump cylinder and a pump swash plate that receives the pump plungers, and a motor cylinder slidingly connected to the hydraulic pump. A hydraulic motor is connected to form a hydraulic closed circuit, and a hydraulic motor is supplied with oil in a motor cylinder to lubricate the sliding surfaces between a large number of motor plungers and a motor swash plate that receives the motor plungers. A hydraulic type in which one of the hydraulic pump and the hydraulic motor is provided with a lubrication chamber that surrounds the sliding surface between the swash plate and the plunger, and the other of the hydraulic pump and the hydraulic motor is surrounded by an oil-tight chamber that communicates with the sliding part. In the transmission device, in order to guide the oil in the oil-tight chamber to the lubrication chamber, a first pressure control valve that opens when the oil pressure in the oil-tight chamber exceeds a set value is installed in the middle of the supply passage connecting the oil-tight chamber and the lubrication chamber. A second pressure control valve is interposed and connected to the supply passage between the first pressure control valve and the lubrication chamber, and the second pressure control valve opens at a hydraulic pressure lower than a set value of the first pressure control valve to release the hydraulic pressure. A hydraulic transmission device featuring: