JPS63214561A - Hydraulic transmission - Google Patents

Abstract

PURPOSE:To effectively use oil discharged from a control pump without the operation of a hydraulic actuator being hindered, by providing such an arrangement that a hydraulic chamber is connected with a pressure control valve through a hydraulic passage which leads oil into an oil chamber when the pressure control valve is opened. CONSTITUTION:A pressure control valve 160 for regulating the hydraulic pressure of a supply oil passage 170 at a predetermined value is connected to the passage 170, and when the valve 150 is opened, excessive oil is fed from the supply oil passage 170 into a lubrication chamber 75 as an oil chamber in a hydraulic motor M. Therefore, it is possible to effectively use oil discharged from a control pump F1. Further, the pressure control valve 150 is opened when hydraulic cylinders 161, 163 as hydraulic actuators are operated, and therefore, the operation of the hydraulic cylinders 161, 163 is not hindered.

Description

Detailed Description of the Invention A0 Object of the Invention (1) Industrial Application Field The present invention relates to a hydraulic pump and a hydraulic motor connected to each other to form a hydraulic closed circuit, and a controlled member included in the hydraulic closed circuit. A pressure control valve that regulates the oil pressure of the supply oil path is connected in the middle of the oil supply path that connects the hydraulic actuator that controls the operation of the hydraulic actuator and the pump that discharges control oil, and surrounds the sliding contact part of the hydraulic pump or hydraulic motor. The present invention relates to a hydraulic transmission device in which an oil chamber is provided.

(2) Prior Art For example, as disclosed in Japanese Unexamined Patent Publication No. 118566/1984, a lubrication chamber is provided to surround the sliding contact portions of the swash plate and shoe of a hydraulic pump or motor and hold lubricating oil. It is known to supply lubricating oil to this lubrication chamber from a replenishment pump.

(3) Problems to be solved by the invention By the way, there is a replenishment pump for replenishing oil to a hydraulic closed circuit configured by interconnecting a hydraulic motor and a hydraulic pump, and a replenishment pump for supplying control oil to a hydraulic actuator. Hydraulic transmission device having a control pump (Japanese Patent Laid-Open No. 57-1
It is conceivable to apply the above-mentioned technique to JP-A No. 03964).

However, although the amount of replenishment oil from the replenishment pump to the hydraulic closed circuit changes constantly because the amount of oil leaking out of the hydraulic closed circuit changes depending on the operating state of the device, the amount of control oil to the hydraulic actuator does not change significantly. The amount of control oil is small because the hydraulic actuator is set to operate smoothly, and if the hydraulic actuator is set to operate quickly and a large amount of control oil is required (even if it is needed, it will be instantaneous). This is because most of the oil discharged from the control pump is usually relieved into the oil tank.

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 effectively utilize the oil discharged from a control pump without interfering with the operation of a hydraulic actuator. With the goal.

B0 Structure of the Invention (1) Means for Solving the Problems According to the present invention, an oil chamber and a pressure control valve are connected via an oil passage that guides oil to the oil chamber when the pressure control valve is opened. Ru.

(2) Effect According to the above configuration, oil is supplied to the oil chamber in response to the opening of the pressure control valve, and the oil discharged from the control pump can be effectively used, and the pressure is controlled when the hydraulic actuator is activated. Since the valve is closed, there is no problem with the operation of the hydraulic actuator.

(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 step-change transmission CVT includes a constant displacement hydraulic pump P connected to an input shaft 2 driven by an engine E, and a variable displacement hydraulic motor M disposed on the same axis as the hydraulic pump P.
They are interconnected to form a hydraulic closed circuit C. The hydraulic motor M has an output shaft 11, a forward and reverse gear device G, and a subshaft 18.
and is connected to the wheels W via a differential device.

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
1 is connected via a clutch valve 116 as a controlled member. A piston rod 162 in a double-acting hydraulic cylinder 161 serving as a hydraulic actuator is connected to this clutch valve 116 . The hydraulic motor M also includes a motor swash plate 63 as another controlled member, and a piston rod 164 of a double-acting hydraulic cylinder 163 as a hydraulic actuator is connected to the motor swash plate 63.

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 C4 and an opening that cuts off between Ch and C1, and when the clubch valve 116 is short-circuited, Since the hydraulic oil is not supplied, a neutral state is established in which the hydraulic motor M is inoperative. Further, when the clutch valve 116 is in the blocking operation, the hydraulic oil is circulated 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 116 reaches an intermediate position, circulation of hydraulic oil occurs in accordance with the opening degree, resulting in a half-clutch state. When the motor swash plate 63 is rotated, the discharge amount of the hydraulic motor M changes, thereby continuously changing the speed of the output shaft 11, that is, the wheels W.

The input shaft 2 includes a control pump F1 and a supply pump F2.
are interlocked and connected, and the discharge port of the control pump F1 is connected to the supply oil line 170, and the discharge port of the replenishment pump F2 is connected to the hydraulic closed circuit C via the supply oil line 137 and the check valves 138, 138. Connected. Switching valves 171 and 172 are interposed between the supply oil passage 170 and the oil tank T, and the ground pressure cylinders 161 and 163, respectively. Actuation direction of cylinders 161, 163, i.e. clutch valve 11
6 and motor swash plate 63 are controlled. Moreover, the operation of both switching valves 171 and 172 is controlled by a control circuit 17-3, which controls the engine rotation sensor S1, throttle opening sensor S2, vehicle speed sensor S3, and shift The operation of the switching valves 171 and 172 is controlled according to signals from the position sensor S4, brake sensor S5, oil temperature sensor S6, engine cooling water temperature sensor S7, and the like.

Further, a pressure control valve 150 that regulates the oil pressure of the supply oil passage 170 to a constant level is connected to the supply oil passage 170, and when this pressure control valve 150 is opened, surplus oil from the oil supply passage 170 is transferred to the hydraulic motor M. Lubrication chamber 75 as an oil chamber in
supplied to Further, a relief valve 50 is connected to the replenishment oil passage 137 to regulate the oil pressure of the replenishment oil passage 137 to a constant level, and surplus oil from the replenishment oil passage 137 is returned to the oil tank T.

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;
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 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 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 2o, an intermediate gear 23 that meshes 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.

Motor cylinder 8 and pump cylinder 4 of hydraulic pump P
An oil-tight chamber 31 is defined between the two, and within this oil-tight chamber 31, a swash plate 32 facing the end surface of the pump cylinder 4 is supported inside the mork cylinder 8. This swash plate 32 has
An annular integral shoe 33 is in sliding contact.

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 is provided with a ring 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 surfaces of the swash plate 32 and the shoe 33 faces the first chamber 31a, and lubricating oil leaking from the sliding surfaces flows into the first chamber 31a. By the way, 1. 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 drilled oil holes 39, 40, 41, it communicates with a pump chamber 45 defined between each plunger 6 and the pump cylinder 4. Therefore, the pump chamber 45
Pressure oil is supplied to the hydraulic pocket 38 through the oil holes 41, 40, 39. This lubricates the sliding surfaces of the shoe 33 and the swash plate 32.

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.

In the lubrication chamber 43, pressure oil in the hydraulic pocket 38 is supplied to the shoe 3.
3 and the swash plate 32, and after the leaked oil fills the lubricating chamber 43, it flows through the roller bearing 42 to the second chamber 3Ib side. Therefore, new lubricating oil is always kept in the lubricating chamber 43, and the oil keeps the sliding surfaces of the shoe 33 and the swash plate 32 on the shoe 3.
3. It is possible to reliably lubricate from the outside.

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.

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 Minshitan 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 against 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 , 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 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 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.

In this case, when the pressure in the lubrication chamber 75 approaches the pressure in the hydraulic pockets 7 and 0, the fluid support function of the hydraulic pocket 70 for the motor shoe 66 is impaired, so the lubrication chamber 75 maintains a pressure state close to atmospheric pressure while retaining the oil. The gaps between the various parts around the presser plate 67 are appropriately selected according to the amount of oil leaking from the hydraulic pocket 70 so as to maintain the amount of oil leaked from the hydraulic pocket 70.

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
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 pilot valve 88.
2 are drilled. Further, the valve hole 87 is communicated with the oil tank T at the bottom of the Mitsilane 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 the IO during each motor plunge 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 accordingly.

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 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 driven to rotate.

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

Rotation speed of motor cylinder 8 Capacity of hydraulic pump P As is clear from this equation, if the capacity of hydraulic motor M determined by the stroke of motor plunger 10 is changed from zero to no value, the gear ratio can be changed to the necessary value of 1. You can change up to.

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 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 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... have been pierced, 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, the high-pressure hydraulic oil generated by the discharge stroke of the plunger 6 is caused to flow into the inner chamber 110 from the discharge boat 112, and further passes through the communication boat 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 boat 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 boats 115 that can communicate between the two short-circuit boats 115 are bored, and a cylindrical clutch valve 116 that opens and closes the short-circuit boats 115 is rotatably fitted into the fixed shaft 108. This clutch valve 116 has a valve hole 117 corresponding to the short-circuit boat 115 on its side wall near its tip, and an operation connection at its base end to which an operation shaft 118 connected to a hydraulic cylinder 161 (see FIG. 1) is connected. A section 119 is provided.

When the clutch valve 116 is rotated to align the valve hole 117 with the shorting boat 115 and fully opened, the clutch is off, and when the valve hole 117 is moved from the shorting boat 115 and fully closed, the clutch is on, and the valve hole 117 and When the shorting boat 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 boat 115, and the hydraulic motor M becomes 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 blocking 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 pump cylinder 4 to be moved through each plunger 6 and the swash plate 32. 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 14'2 for selectively switching the state of communication with 0 is provided.

This switching valve 142 operates to connect the side passages 139 and 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
One end of the link 127, 128 is connected to the 0, and the other end of the link 127 is interlocked and connected to a rotation shaft 129 rotated by a hydraulic cylinder 163 (see FIG. 1). Further, a cam 130 is provided on the rotation shaft 129, and a cam follower 131 that comes into sliding contact with the cam 130 is provided on the other end of the link 128. As a result, the motor swash plate 6
When the servo motor 81 is actuated to bring the valve 3 into the upright position, the servo motor 121 is actuated to close the discharge port 112 with the closing valve 124.

A replenishment pump F is provided on the outside of the end wall of the case half 1a.
2 is equipped. This replenishment pump F2 is driven by the input shaft 2, and pumps up oil from the oil tank T at the inner bottom of the mission case 1.

The discharge port 136 of the replenishment pump F2 is communicated with a replenishment oil passage 137 formed in the input shaft 2, and this replenishment oil passage 137 communicates with the inner chamber 110 via a check valve 138, and also communicates with the inner chamber 110 via a check valve 138. It communicates with the outer chamber 111 via a stop valve. Further, an open oil passage 174 that opens into the mission case 1 and communicates with the oil tank T at the bottom of the mission case 1 is bored in the end wall of the case half 1a.

A relief valve 50 is interposed between the supply oil passage 137 and the release oil passage 174. The relief valve 50 includes a spool 178 that operates according to the balance between the hydraulic pressure of a hydraulic chamber 176 that communicates with the discharge boat 136 and the spring force of a spring 177 that opposes the hydraulic pressure. Accordingly, communication and interruption between the supply oil passage 137 and the release oil passage 174 are switched.

On the other hand, a pressure control valve 15 is provided in the middle of the oil passage 180 connecting the oil supply passage 170 and the lubrication chamber 75 of the hydraulic motor M, which opens when the oil pressure of the oil supply passage 170 exceeds a certain value.
0 is inserted.

Next, to explain the operation of this embodiment, the pressure control valve 150 opens when the control oil pressure to the hydraulic cylinders 161, 163, that is, the oil pressure in the supply oil path 170, becomes higher than a set value, and the excess oil is transferred to the hydraulic motor M. The oil pressure is supplied to the lubricating chamber 75 in the oil pressure cylinders 161 and 163, and the control oil pressure to the hydraulic cylinders 161 and 163 is kept almost constant.

Furthermore, the amount of oil required by the hydraulic cylinders 161, 163 is small, and the switching valves 171, 172 are not operated frequently, so oil can be smoothly supplied to the lubrication chamber 75. Moreover, the pressure control valve 150 opens only when the oil pressure in the supply oil passage 170 is high, that is, when the hydraulic cylinder 161.163 is not operating. It does not interfere with the operation of the

FIG. 3 shows another embodiment of the present invention, and parts corresponding to those in the previous embodiment are given the same reference numerals.

An oil passage 48 communicating with the first chamber 31a of the oil-tight chamber 31 as an oil chamber is formed between the input shaft 2 and the output shaft 11, and an oil passage 48 communicating with the core oil passage 48 is formed in the end wall of the case half 1a. An oil passage 49 is bored. Furthermore, supply oil passage 170 and oil passage 4
9 are connected via an oil passage 180 having a pressure control valve 150.

Further, the motor cylinder 8 is provided with a plurality of discharge holes 181 for discharging the oil in the oil-tight chamber 31, and each discharge hole 18
The diameter of the hole 1 is set to be small enough to sufficiently hold lubricating oil within the oil-tight chamber 31.

According to this embodiment, surplus oil from the supply oil passage 170 can be effectively utilized and supplied to the oil-tight chamber 31.

FIG. 4 shows still another embodiment of the present invention,
An oil passage 48' communicating with the first chamber 31a of the oil-tight chamber 31 is bored in the motor cylinder 8, and a pressure control valve 1 is connected to the oil passage 48'.
An oil passage 180 having a diameter of 50 is connected via an oil passage 49 .

This embodiment also provides the same effects as the embodiment shown in FIG.

C0 Effects of the Invention As described above, according to the present invention, the oil chamber and the pressure control valve are connected via the oil path that guides oil to the oil chamber when the pressure control valve is opened, so that oil is supplied to the hydraulic actuator. It is possible to maintain the oil pressure approximately constant to ensure its operation, and to supply surplus oil in the supply oil path to the oil chamber for effective use.

[Brief explanation of the drawing]

1 and 2 show one embodiment of the present invention, FIG. 1 is a hydraulic circuit diagram, FIG. 2 is a vertical side view showing a specific structure, and FIGS. 3 and 4 are FIG. 3 is a vertical sectional side view corresponding to FIG. 2 of another embodiment of the present invention. 31... Oil-tight chamber as an oil chamber, 63... Motor swash plate as a controlled member, 75... Lubrication chamber as an oil chamber,
116... Clutch valve as controlled member, 161° 163... Hydraulic cylinder as hydraulic actuator, 150... Pressure control valve, 170... Supply oil path, C
...Hydraulic closed circuit, Fl...Control pump, M...
Hydraulic motor, P...hydraulic pump

Claims (1)

[Claims] A hydraulic pump and a hydraulic motor are interconnected to form a hydraulic closed circuit, and a supply oil path connects a hydraulic actuator that controls the operation of a controlled member included in the hydraulic closed circuit and a control pump that discharges control oil. In a hydraulic transmission device in which a pressure control valve that regulates the oil pressure of the supply oil path is connected to the oil supply passage, and an oil chamber is provided surrounding the sliding part of the hydraulic pump or hydraulic motor, there is a gap between the oil chamber and the pressure control valve. , a hydraulic transmission device characterized in that the pressure control valve is connected via an oil passage that guides oil to an oil chamber when the pressure control valve is opened.