JPS63214558A - hydraulic transmission - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention A0 Object of the Invention (11 Industrial Field of Application) The present invention relates to a motor cylinder that is rotatably supported by a casing and that coaxially surrounds an input shaft. A hydraulic motor includes a plunger that is in sliding contact with a motor swash plate, and a plurality of pump plungers are slidably connected in an annular arrangement to a pump cylinder that is connected to an input shaft rotatably supported by a casing and are interlocked with the motor cylinder. A hydraulic pump in which each pump plunger is in sliding contact with a pump swash plate is connected to form a hydraulic closed circuit, and the pump cylinders are coaxially surrounded by a motor cylinder to define an oil-tight chamber between them. The present invention relates to a hydraulic transmission device in which a replenishment pump and a hydraulic closed circuit, which are interlocked and arranged in a casing, are connected via a replenishment oil path.

(2) Prior Art In a hydraulic transmission device in which a hydraulic pump and a hydraulic motor are connected to form a hydraulic closed circuit, for example, as disclosed in Japanese Patent Application Laid-open No. 56-143857, a hydraulic closed circuit is disclosed. It is known that the oil relieved from the relief valve that regulates the discharge pressure of the replenishment pump for replenishing hydraulic oil is supplied to the oil-tight chamber surrounding the hydraulic pump or hydraulic motor as lubricating oil for each sliding contact part. There is.

(3) Problems to be Solved by the Invention However, when considering applying the above technology to a hydraulic pump of a hydraulic transmission device as disclosed in Japanese Patent Laid-Open No. 57-76357, it is difficult to see if the hydraulic pump rotates. Not only that, but the hydraulic motor surrounding the hydraulic pump also rotates, making it difficult to introduce the oil relieved from the relief valve into the oil-tight chamber without significantly changing the conventional configuration and size.

The present invention has been made in view of the above circumstances, and provides a hydraulic transmission device that can introduce surplus oil from a supply oil path into an oil-tight chamber without significantly changing the conventional structure and size. The purpose is to

B9 Structure of the Invention (Means for Solving Problems 11) According to the present invention, a relief valve that opens when the oil pressure in the supply oil passage exceeds a set value is disposed in the casing, and the oil-tight chamber and the relief valve An oil passage is provided between the motor cylinder or between the motor cylinder and the input shaft.

(2) Effect According to the above configuration, the oil passage connecting the relief valve and the oil-tight chamber is connected to the relief valve regardless of the rotation of the motor cylinder, and the oil passage connecting the relief valve and the oil-tight chamber is connected to the relief valve, so that the replenishment oil can be maintained without changing the conventional structure and size. Excess oil from the road can be guided into the oil-tight room.

(3) Example Below, an example 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 stepped transmission CVT includes a constant discharge type hydraulic pump P connected to an input shaft 2 driven by an engine E, 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
B and 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 CX 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
2 are connected via a 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 high-pressure and low-pressure oil lines ch, cz, and the hydraulic oil pumped up from the oil tank T is connected to the hydraulic closed circuit C via the supply oil line 137 to replenish the shortage. supplied to

Furthermore, a relief valve 50 is connected in the middle of the replenishment oil passage 137, which opens when the oil pressure of the replenishment oil passage 137 exceeds a set value in order to keep the discharge pressure of the replenishment pump F constant. The oil relieved from the valve 50 is introduced into the oil-tight chamber 31 of the hydraulic pump P.

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 Cl and an opening that cuts off between both channels ch and cz, and when the clutch valve 116 is in short-circuit operation, the hydraulic pressure Since the hydraulic oil is not supplied to the motor M, it becomes a neutral state in which the hydraulic motor M is inactive.Furthermore, when the clutch valve 116 is in the blocking operation, hydraulic oil is not supplied between the hydraulic pump P and the hydraulic motor M. Since the circulation effect occurs, the driving force is transmitted, and the vehicle is brought into a running state.

Furthermore, when the opening degree of the clutch valve 116 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 a casing formed by combining 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;
and a large number of motor plungers 10, 10, . . . which are slidably engaged with a number of cylinder holes 9, 9, .

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 pole bearing 1.
4 to the end wall of the other case half 1b.

The input shaft 2 oil-tightly penetrates the end wall of one case half 1a, and is disposed concentrically within the output shaft 11 that is integrated with the motor cylinder 8. Moreover, a plurality of needle bearings 15 are interposed between the inner surface of the output shaft 11 and the outer surface of the input shaft 2, so that the input shaft 2 and the pump cylinder 4 are relative to the output shaft 11 and the motor cylinder 8. It is rotatable.

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 22a, which are integrally provided on opposing parts of the drive clutch toothed wheels 21a and 22a. A shift fork 26 is engaged with the clutch member 25 to selectively operate the clutch member 25.

A gear 28 meshing with an input gear 27 of the differential is integrally provided on the countershaft 18, and the differential is switched between the forward and reverse directions of the vehicle in response to the operation of the clutch member 25. Driven.

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 pump 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 pump 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 peripheral stepped portion of the motor cylinder 3 via a roller bearing 42.
Furthermore, a spring holder 35 connected to the input shaft 2 via a spline 36 abuts on the presser ring 34 in order to allow movement in the axial direction and prevent relative rotation. A coil spring 37 surrounding the human power shaft 2 is interposed between the spring holder 35 and the pump cylinder 4, and the spring force of the coil spring 37 causes the spring holder 35 to press against the shoe 33 via the retaining ring 34. is elastically pressed toward the pump swash plate 32. 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 pump 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 pump 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 31a. By the way, pump swash plate 3
2 and the shoe 33, the shoe 33
An annular hydraulic pocket 38 is provided on the front side of the
This hydraulic pocket 38 communicates with the pump chamber 45 defined between each plunger 6 and the pump cylinder 4 via the shoe 33, the connecting rod 44, and oil holes 39, 40, 41 bored in the plunger 6. be done. Therefore, the pressure oil in the pump chamber 45 is supplied to the hydraulic pocket 38 through the oil holes 41, 40.39.

As a result, the sliding surfaces of the shoe 33 and the pump swash plate 32 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 and the pump swash plate 32 are arranged so as to face the outer circumferential side of the sliding surface between the pump swash plate 32 and the shoe 33.
, the shoe 33 and the roller bearing 42 define an annular lubrication chamber 43 surrounding the sliding surface, and this lubrication chamber 43 constitutes a part of the second chamber 31b.

In the lubrication chamber 43, pressure oil in the hydraulic pocket 38 flows into the shoe 33.
The leaked oil constantly leaks through the sliding surface between the pump swash plate 32 and the lubricating chamber 43, and then flows through the roller bearing 42 to the second chamber 31b. Therefore, new lubricating oil is always kept in the lubricating chamber 43, and the sliding surfaces of the shoe 33 and the pump swash plate 32 are 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, an oil 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 oil passage 48 is connected to the relief valve 50.

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 of the mission case 1.

The discharge boat 136 of this replenishment pump F communicates with a replenishment oil passage 137 provided in the input shaft 2, and the replenishment oil passage 1
37 communicates with the hydraulic closed circuit C via a check valve 138 disposed on the distribution panel 46. 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.

The relief valve 50 is connected to the discharge boat 13 of the replenishment pump F.
It is interposed between the oil passage 49 communicating with the oil passage 6 and the oil passage 51 communicating with the oil passage 48, and is disposed in the case half 1a.

In FIG. 4, the relief valve 50 includes a bottomed cylindrical spool valve element 52 for switching between communication and isolation between the oil passages 49 and 51, and a spring 53 that biases the spool valve element 52 in the blocking direction. Be prepared. A bottomed hole 54 parallel to the input shaft 2 is bored in the end wall of the case half 1a of the mission case 1, and the spool valve body 52 has an oil chamber 55 between it and the closed end of the bottomed hole 54. , and is slid into the bottomed hole 54.

Further, the support member 57 is restricted from moving toward the open end of the bottomed hole 54 by a retaining ring 56 fitted in the middle of the bottomed hole 54.
is inserted into the bottomed hole 54, and a spring 53 is interposed between the support member 57 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 is communicated with an oil passage 49 that communicates with the discharge boat 136 and is bored in the end wall of the case half 1a. Further, an annular groove 58 is provided in the middle of the bottomed hole 54, and the annular groove 58 can be switched between communicating with and blocking the oil chamber 55 by the spool valve body 52. The oil passage 51 is communicated with the annular groove 58.

Therefore, the relief valve 50 opens when the oil pressure in the oil chamber 55, that is, the oil pressure in the replenishment oil passage 137 becomes larger than the value set by the spring 53, and regulates the oil pressure in the replenishment oil passage 137 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 is rotationally driven synchronously via the bevel gears 61 and 62. . 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.
These trunnion shafts 65 are pivotally supported by the mission case 1. 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 press 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 connection portion between each motor shoe 66 and each motor plunger 10 penetrates 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 the motor shoe 66 communicates with the hydraulic pocket 70 through a series of oil holes 72 and 73 formed in the motor plunger 10 and the motor shoe 66. Therefore, the pressure oil in the hydraulic chamber 71 is supplied to the hydraulic pocket 70 through the oil hole 72.73, and the motor plunger 10
Pressure is exerted on the motor shoe 66 so as to receive the protruding thrust of the motor shoe 66 .

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 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 therebetween.
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 is constantly leaking through the sliding surfaces of the motor shoes 66 and 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.

In this case, the pressure in the lubrication chamber 75 approaches the pressure in the hydraulic pocket 70 (and the hydraulic pressure is lost), and the fluid support function of the motor shoe 66 of the lubrication chamber 75 is impaired, so the lubrication chamber 75 maintains a pressure state close to atmospheric pressure. In order to retain oil, the gaps between the various parts around the presser plate 67 are appropriately selected depending on the amount of oil leaking from the hydraulic pocket 70.

A servo motor 81 is provided in the mission case l 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
The pilot valve 88 penetrates the end wall on the fourth side oil-tightly and movably.

The piston rod 86 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 viroft valve 88.
2 are drilled. Furthermore, the valve hole 87 is communicated with the oil tank T at the bottom of the transmission case 1 via a reflux path 93.

The servo piston 85 is amplified by the hydraulic pressure supplied from the oil passage 90 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 10. At this time, the motor swash plate 63 gives reciprocating motion to each motor plunger 10 as the motor cylinder 8 rotates, causing it to expand and contract repeatedly, but the stroke of the motor plunger 10 depends on the inclination of the motor swash plate 63. It is adjusted steplessly.

A hydraulic closed path C is formed between the hydraulic pump P and the hydraulic motor M via the distribution panel 46 and the 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 10 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 10 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 period, 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 the distribution board 46, and the support shaft 12 is integrally provided in the fourth portion 8d.

The first and fourth parts 8b to 8d are connected by a plurality of bolts 98, and the second. The third and fourth parts 8b to 8d are integrally connected by a plurality of bolts 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 port 112.1.
13 is bored, and its discharge port 112 connects the pump chamber 45 and inner chamber 11 of the plunger 6 during 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... have been drilled, and these communication boats 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, high-pressure hydraulic oil generated by the discharge stroke of the plunger 6 flows into the inner chamber 110 from the discharge port 112, 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 10 to apply thrust to the motor plunger 10. On the other hand, the hydraulic oil discharged by the motor plunger 10 in the contraction stroke returns to the pump chamber 45 of the plunger 6 in the suction stroke via the communication port 114 communicating with the outer chamber 111 and the suction port 113, 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 port 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 that is operated by a biloft 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 port 112 is swingably attached to its tip. By moving the servo piston 122 to the left, the discharge port 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 110 and an oil passage 14 communicating with the outer chamber 111.
0 is punctured. In addition, 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 both side passages 139, 14 are connected to the oil passage 141.
A switching valve 142 that selectively switches the state of communication with 0 is provided.

This switching valve 142 operates to connect the side passages 139, 140 with higher oil pressure 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 is connected to one end of a link 127.12'8, and the other end of the link 127 is interlocked and connected to a rotation shaft 129 that is rotated by an operation means (not shown). Further, a cam 130 is provided on the rotation shaft 129, and a cam 130 is provided on the rotation shaft 129.
A cam follower 131 that is in sliding contact with the cam 130 is provided at the other end of the cam follower 131 .

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
The closing valve 124 operates to close the discharge port 1'12.

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. The remaining leaked 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 the communication path 47, and the relief valve 50
When the valve is opened, the hydraulic oil that is relieved is guided from the supply oil passage 137.

In this way, the replenishment oil passage 137 leading to the replenishment pump F
Excess oil is supplied to the oil-tight chamber 31 via the relief valve 50, but since the oil passage 48 is provided between the motor cylinder 8 and the input shaft 2, the oil-tight chamber 31 can be filled without significantly changing the conventional structure and size. Excess oil from the replenishment pump F can be led to 31.

FIG. 5 shows another embodiment of the present invention, in which an oil passage 48' connecting the oil-tight chamber 31 and the relief valve 50 may be provided in the motor cylinder 8.

C0 Effects of the Invention As described above, according to the present invention, a relief valve that opens when the oil pressure in the supply oil passage exceeds a set value is disposed in the casing, and the oil passage that connects the oil-tight chamber and the relief valve. is provided between the motor cylinder or the motor cylinder and the input shaft, so even though the motor cylinder and pump cylinder rotate, it is possible to connect the oil-tight chamber and supply oil path without significantly changing the conventional structure and size. , surplus oil from the replenishment pump can be supplied to the oiltight chamber.

[Brief Description of the Drawings] Figures 1 to 4 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 vertical side view showing the specific structure of the continuously variable transmission, Figure 3 is an enlarged view of the main parts of Figure 2, and Figure 4 is an enlarged view of the main parts of Figure 2. The figure is an enlarged view of the section ``■'' in FIG. 2, and FIG. 5 is an overall longitudinal sectional side view corresponding to FIG. 2 of another embodiment of the present invention. 2... Input shaft, 4... Pump cylinder, 6... Bomb plunger, 8... Motor cylinder, 10...
Motor plunger, 31... Oil-tight chamber, 32... Pump swash plate, 48.48'... Oil path, 50... Relief valve, 63... Motor swash plate, 137... Supply oil path , C...Hydraulic closed circuit, F...Replenishment pump, M...Hydraulic motor, P...Hydraulic pump

Claims (1)

[Claims] A hydraulic motor is rotatably supported by a casing, and has a number of motor plungers slidably connected to a motor swash plate in an annular arrangement to a motor cylinder coaxially surrounding an input shaft. A hydraulic pump has a plurality of pump plungers slidably connected in an annular arrangement to a pump cylinder connected to a pump input shaft, and each pump plunger is slidably connected to a pump swash plate that is interlocked with the motor cylinder, forming a hydraulic closed circuit. The pump cylinders are coaxially surrounded by a motor cylinder to define an oil-tight chamber between them, and a replenishment pump and a hydraulic closed circuit, which are disposed in the casing in conjunction with the input shaft, are connected via a replenishment oil path. In a hydraulic transmission device that is connected to , or a hydraulic transmission device characterized in that it is provided between a motor cylinder and an input shaft.