KR20200002609A - Power transfer device - Google Patents

Abstract

Provided is a power transfer device with an improved valve configuration or an improved flow path configuration. A relief valve (73) is provided with a holder (91) having a valve seat (135) which supports a poppet (92). Moreover, the holder (91) is provided with a mounting part (103) installed on a valve body (72). Therefore, the relief valve (73) can be assembled to the valve body (72) by installing the mounting part (103) on the valve body (72) after subassembly by assembling a poppet (92), an adjustment screw (93), and a spring (94) to the holder (91).

Description

Power transmission unit {POWER TRANSFER DEVICE}

The present invention relates to a power transmission device mounted on a work vehicle such as a combine.

For example, a crawler is employ | adopted for a pair of left and right traveling apparatuses because the stationary frequency capability is required for work vehicles, such as a combine. In a work vehicle employing this crawler, it is necessary to shift the power transmitted to the left and right crawlers in order to turn the aircraft left and right. For example, when the power lower than the power transmitted to one crawler is transmitted to the other crawler, the gas makes a complete turn to the other crawler side. In addition, the power transmitted to the one crawler and the power in the reverse direction are transmitted to the other crawler, so that the gas turns to the other crawler side.

Therefore, the transmission which transmits power to a left-right crawler is equipped with the clutch for switching a power transmission path with a some shaft and a gear. Moreover, the valve unit which accommodates the valves which control the supply of hydraulic pressure to a clutch in the valve case is provided in the outer surface of the transmission case which forms the outer shell of a transmission.

Japanese Patent Publication No. 2009-78699

In such a work vehicle, there is room for improvement in the configuration of a valve provided in the valve unit and a flow path for supplying hydraulic pressure to the clutch from the valve.

An object of the present invention is to provide a power transmission device in which an improvement in a valve configuration or a flow path configuration is achieved.

In order to achieve the above object, a power transmission device according to an aspect of the present invention, the power including a transmission having a clutch operated by hydraulic pressure, and a valve unit having a valve body and a valve provided in the valve body It is a transmission apparatus, The valve contains the relief valve which adjusts the oil pressure in the flow path formed in the valve body below relief pressure, The relief valve is accommodated in the holder which has a normal peripheral wall, and is accommodated in a holder, and a center line direction of a holder. A poppet provided to be movable, an adjustment member inserted from one side in the centerline direction in the holder, and a spring interposed between the poppet and the adjustment member to press the poppet to the other side opposite to the one side in the centerline direction, In the peripheral wall of the holder, an installation portion provided on the valve body is formed on the outer circumferential surface, and the valve seat receiving the poppet is provided on the inner circumferential surface. It is formed.

According to this structure, the relief valve is provided with the holder in which the valve seat which receives a poppet is formed. In the conventional structure which is not equipped with this holder, the valve seat which receives a poppet is formed in a valve body. The valve body is, for example, made of aluminum and cast by diecast. Therefore, there exists a problem that the fluctuation | variation of the processing precision of the seat surface of a valve seat is large, and also time-dependent deterioration, such as abrasion of a seat surface, arises and a relief pressure is not stabilized. By using the holder in which the valve seat of the poppet is integrally formed, the seat surface can be stabilized both in terms of initial performance and durability, and the relief pressure can be stabilized. By increasing the stability of the relief pressure, the fluctuation in the behavior of the power transmission device can be reduced. In addition, the relief pressure can be easily adjusted, and the variation in the relief pressure at the time of factory shipment of the power transmission device or the work vehicle equipped with the power transmission device can be reduced.

Moreover, the mounting part provided in the valve body is formed in the holder. Therefore, the relief valve can be assembled to the valve body by assembling the poppet, the adjustment member and the spring to the holder, and then attaching the mounting portion to the valve body. Therefore, the relief pressure can be set and adjusted in the state of the subassembly, and further improvement of the stability of the relief pressure can be achieved.

It is preferable that the guide part which guides the movement of a poppet is formed in the peripheral wall of a holder. In the structure in which relief oil flows along the surface which guides the movement of a poppet, the area of the flow path through which relief oil flows changes with respect to the lift amount of a poppet. On the other hand, by providing the guide part independent of the valve seat, it is possible to suppress the sudden change in the area of the flow path through which the relief oil flows with respect to the lift amount of the poppet.

In the peripheral wall of a holder, the 1st connection hole and the 2nd connection hole are respectively penetrated and formed in the position spaced apart in the centerline direction, and a relief valve is externally fitted to the peripheral wall between a 1st connection hole and a 2nd connection hole. And an annular seal which liquid-tightly contacts the valve body and divides the space between the valve body and the peripheral wall into a pump port through which the first connection hole communicates with a tank port with which the second connection hole communicates. You may be.

The supporting member is integrally formed with the adjustment member to support one end of the spring. Thereby, since it is not necessary to form a support part as a separate part, the number of parts can be reduced and the number of assembly processes can be reduced.

The adjustment member may be an adjustment screw screwed into the holder. In this case, it is preferable that the installation portion is provided so as not to rotate relative to the valve body. Thereby, when the adjustment member is screwed into the holder, it is possible to suppress the holder from rotating with the adjustment member. Therefore, the adjustment member can be operated well, and the adjustment work of the relief pressure is facilitated.

A power transmission device according to another aspect of the present invention includes a valve unit having a clutch operated by hydraulic pressure, a transmission for transmitting power to a left and right traveling device, and a valve body and a valve provided in the valve body. It is a power transmission device, the clutch includes a left transmission gear for transmitting the power transmitted to the side clutch shaft to the left traveling device, a left side clutch for engaging and releasing the engagement, and a power transmitted to the right side for the right clutch. The right transmission gear to be transmitted to the device and the right side clutch for engaging and releasing the engagement are included, and the side clutch shaft includes a left supply passage for supplying hydraulic oil to the left side clutch and a right supply passage for supplying hydraulic oil to the right side clutch. And hydraulic oil supplied to the left side clutch and the right side clutch in excess The conveying flow path is formed by extending in the axial direction, respectively, and the left supply flow path, the right supply flow path and the conveying flow path communicate with the flow path formed in the valve body in the valve body, The sealing ring which seals between a side clutch shaft and a valve body is provided in the transmission side rather than each communicating part of a flow path and a flow path.

According to this structure, the side clutch shaft extends in a valve body, and the left supply flow path, the right supply flow path, and the conveyance flow path which are formed in the side clutch shaft communicate with the flow path in the valve body. For this reason, the side clutch shaft and the valve body are provided by providing a seal ring on the transmission side rather than the communication portions of the left supply flow path, the right supply flow path and the transfer flow path and the flow path, and bringing the seal ring into liquid sealing contact with the valve body. You can seal between.

For example, in the structure in which the flow path communicating with the conveyance flow path is formed in the fitting surface of a transmission and a valve unit, the seal ring arrange | positioned at the transmission side rather than the communication site | part is provided in a transmission. Therefore, when the seal ring is broken at the time of assembly, the problem cannot be detected until the final inspection after assembling the transmission and the valve unit. In addition, when a problem of a seal ring is detected, in order to replace the seal ring, a transmission must be disassembled and a loss time occurs in a manufacturing process.

In the configuration in which the seal ring is provided in the valve unit, a problem of the seal ring can be detected in the state of the valve unit alone, and the cause of occurrence of the problem can be detected and the replacement work of the seal ring is easy. Therefore, the loss time in a manufacturing process can be made small, and manufacturing quality can be improved and stabilized.

According to the present invention, it is possible to provide a power transmission device capable of improving the valve configuration or the flow path configuration.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows the structure of the power transmission device which concerns on one Embodiment of this invention.
2 is a left side view of the valve unit.
FIG. 3 is a cross-sectional view of the valve unit at cut line AA shown in FIG. 2.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described in detail, referring an accompanying drawing.

<Mechanical configuration of the power transmission device>

1: is sectional drawing which shows the structure of the power transmission device 1 which concerns on one Embodiment of this invention.

The power transmission device 1 is mounted in a combine, for example. The combine is equipped with an engine and HST (Hydro Static Transmission) for shifting the power of the engine. The power transmission device 1 is mounted in order to transmit the power output by the HST to traveling devices such as a left and right pair of crawlers.

The power transmission device 1 is provided with the transmission case 11 which forms an outer shell. In addition, the power transmission device 1 includes an input shaft 12, a sub transmission shaft 13, a side clutch shaft 14, and a swing clutch shaft 15. The input shaft 12, the sub transmission shaft 13, the side clutch shaft 14, and the swing clutch shaft 15 are parallel to each other, and each of the transmission cases 11 is capable of holding the rotation about the axis. Supported.

Power is input to the input shaft 12 from HST. The high speed drive gear 21 and the low speed drive gear 22 are fixedly held by the input shaft 12 at intervals in the axial direction of the input shaft 12.

The high speed driven gear 23 and the low speed driven gear 24 are held in the sub transmission shaft 13 so as to be relatively rotatable. The high speed driven gear 23 is engaged with the high speed drive gear 21, and the low speed driven gear 24 is engaged with the low speed drive gear 22. Therefore, a space | interval is provided between the high speed driven gear 23 and the low speed driven gear 24, and the shifter 25 is provided between them. The shifter 25 is externally fitted to the sub transmission shaft 13, and is provided to be movable in the axial direction of the sub transmission shaft 13. Splines are formed on the inner circumferential surface of the shifter 25, and the shifter 25 is splined only with the sub transmission shaft 13 in a state where the shifter 25 is located at an intermediate position between the high speed driven gear 23 and the low speed driven gear 24. do. When the shifter 25 moves toward the high speed driven gear 23 at its intermediate position, the shifter 25 is splined to both the sub transmission shaft 13 and the high speed driven gear 23. In addition, when the shifter 25 moves toward the low-speed driven gear 24 from the intermediate position, the shifter 25 is splined to both the sub transmission shaft 13 and the low-speed driven gear 24.

In the state where the shifter 25 is splined with both the sub transmission shaft 13 and the high speed driven gear 23, the power input to the input shaft 12 is driven by the high speed drive gear 21, the high speed driven gear 23, and It is transmitted to the sub transmission shaft 13 through the shifter 25. In the state where the shifter 25 is splined to both the sub transmission shaft 13 and the low speed driven gear 24, the power input to the input shaft 12 is the low speed drive gear 22 and the low speed driven gear 24. And the shifter 25 to the sub transmission shaft 13. The gear ratio of the high speed drive gear 21 and the high speed driven gear 23 is smaller than the gear ratio of the low speed drive gear 22 and the low speed driven gear 24. Therefore, by the position of the shifter 25, the power of the input shaft 12 is transmitted to the sub transmission shaft 13 shifted in two stages of high speed and low speed. In the state where the shifter 25 is engaged with only the sub transmission shaft 13, the power of the input shaft 12 is in a neutral state where the power is not transmitted to the sub transmission shaft 13.

On the left side of the high-speed driven gear 23, the straight gear 26 and the turning gear 27 are fixedly held on the sub transmission shaft 13.

The side clutch input gear 28 is held by the side clutch shaft 14 so as to rotate integrally by spline coupling. The side clutch input gear 28 is meshed with the straight gear 26. Therefore, the power transmitted to the sub transmission shaft 13 is transmitted to the side clutch shaft 14 via the straight gear 26 and the side clutch input gear 28.

In addition, the left output gear 31 and the right output gear 32 are held by the side clutch shaft 14 so as to be relatively rotatable at intervals in the axial direction of the side clutch shaft 14, respectively. The left output gear 31 meshes with the left transmission gear 33 that outputs power toward the left travel device. The right output gear 32 meshes with the right transmission gear 34 which outputs power toward the right traveling device.

The left side clutch 41 is provided on the left side (right side in FIG. 1) of the left output gear 31. The left side clutch 41 is provided with the left engagement body 42, the spring 43, and the piston 44. As shown in FIG. The left engagement body 42 is splined to the side clutch shaft 14 and is hold | maintained so that the side clutch shaft 14 is movable in the axial direction. The left engagement body 42 has an internal tooth 45 which can be engaged with the left output gear 31. The spring 43 is a coil spring and is interposed in the compressed state between the side clutch input gear 28 and the left engagement body 42. The left engagement body 42 is urged to the left output gear 31 side by the elastic force of the spring 43. As shown in FIG. The piston 44 is provided on the left output gear 31 side with respect to the left engagement body 42, and is externally fitted to the side clutch shaft 14 so that a movement to the axial direction is possible. An oil chamber 46 is formed between the piston 44 and the left output gear 31.

The right side clutch 51 is provided on the right side (left side in FIG. 1) of the right output gear 32. The right side clutch 51 is provided with the right engagement body 52, the spring accommodating member 53, the spring 54, and the piston 55. The right engagement body 52 is splined to the side clutch shaft 14, and is hold | maintained so that the side clutch shaft 14 is movable in the axial direction. The right engagement body 52 has the internal tooth 56 which can be engaged with the right output gear 32. Further, on the outer circumferential surface of the right engagement body 52, a plurality of outer teeth 57 are arranged in the circumferential direction. The spring receiving member 53 is externally fitted to the side clutch shaft 14 so as to be movable in the axial direction thereof. The spring 54 is a coil spring and is interposed in the compressed state between the right engagement body 52 and the spring receiving member 53. The right engagement body 52 is urged to the right output gear 32 side by the elastic force of the spring 54. The piston 55 is provided on the right output gear 32 side with respect to the right engagement body 52, and is externally fitted to the side clutch shaft 14 so that a movement to the axial direction is possible. An oil chamber 58 is formed between the piston 55 and the right output gear 32.

Moreover, the output relay gear 59 is hold | maintained by the side clutch shaft 14 between the left output gear 31 and the right output gear 32 so that relative rotation is possible.

The soft clutch input gear 61 is hold | maintained so that the rotation clutch shaft 15 can rotate relatively. The soft clutch input gear 61 is engaged with the outer tooth 57 of the right engagement body 52 of the right side clutch 51. A soft clutch 62 is provided between the swing clutch shaft 15 and the soft clutch input gear 61. The soft clutch 62 is a wet multi-plate clutch and is engaged and released by hydraulic pressure. By engaging the soft clutch 62, the turning clutch shaft 15 and the soft clutch input gear 61 are engaged, and by releasing the soft clutch 62, the turning clutch shaft 15 and the soft clutch input gear are engaged. 61 is separated.

In addition, the spin clutch input gear 63 is held by the swing clutch shaft 15 so as to be relatively rotatable. The spin clutch input gear 63 meshes with the turning gear 27 held by the sub transmission shaft 13. The spin clutch 64 is provided between the turning clutch shaft 15 and the spin clutch input gear 63. The spin clutch 64 is a wet multi-plate clutch and is engaged and released by hydraulic pressure. By engaging engagement of the spin clutch 64, the turning clutch shaft 15 and the spin clutch input gear 63 are engaged, and by releasing the spin clutch 64, the turning clutch shaft 15 and the spin clutch input gear. 63 is separated.

In addition, the swing output gear 65 is integrally held by the spline coupling between the soft clutch 62 and the spin clutch 64 by the spline coupling. The swing output gear 65 meshes with the output relay gear 59 held by the side clutch shaft 14.

In addition, a left swing clutch 66 is provided between the output relay gear 59 and the left output gear 31. The right turning clutch 67 is provided between the output relay gear 59 and the right output gear 32. The left swing clutch 66 and the right swing clutch 67 are wet multi-plate clutches. In addition, in the left turning clutch 66 and the right turning clutch 67, a plurality of clutch plates and a clutch disk are alternately provided, and the left turning clutch 66 and the right turning clutch 67 are hydraulically inclined. Even in a non-supply state, power is transmitted while slipping between the clutch plate and the clutch disk.

The valve unit 71 is provided on the left side of the transmission case 11 so as to collectively face the side clutch shaft 14 and the swing clutch shaft 15 from the left side. The valve unit 71 is provided with valves including a valve body 72 in which a flow path constituting a hydraulic circuit is formed, and a relief valve 73 described later.

The side clutch shaft 14 penetrates the transmission case 11 and enters the valve body 72. Inside the side clutch shaft 14, the left supply flow path 74, the right supply flow path 75, and the conveyance flow path 76 each extend in the axial direction, and are formed. The left supply flow path 74, the right supply flow path 75, and the transfer flow path 76 communicate with the flow path formed in the valve body 72 within the valve body 72. Specifically, the left supply flow path 74 communicates with the flow path formed in the valve body 72 at the leftmost position. The communication part which the left supply flow path 74 and the flow path communicate with is not shown in the cross section shown in FIG. The communication part 77 which the right supply flow path 75 and the flow path communicate with is spaced apart to the right with respect to the communication part which the left supply flow path 74 communicates with. The communication part 78 which the conveyance flow path 76 and the flow path communicate with is located in the right side of the communication site which the left supply flow path 74 communicates with, and the left side of the communication part 77.

The three seal rings 81, 82, 83 are interposed between the side clutch shaft 14 and the valve body 72. Seal rings 81 and 82 are arranged so that the communication site | part 77 is picked up from right and left, and seal rings 82 and 83 are arranged so that the communication site | part 78 is picked up from right and left. The communication site | part which the left supply flow path 74 and the flow path communicate with is located in the right side rather than the seal ring 83. Thereby, the communication site | part which the left supply flow path 74 communicates with, the communication site | part 77 where the right supply flow path 75 communicates with the flow path, and the communication site 78 which the conveyance flow path 76 and the flow path communicate with, It is isolated so that there is no flow of hydraulic fluid between them.

The swing clutch shaft 15 penetrates the transmission case 11 and enters the valve body 72. Inside the swing clutch shaft 15, supply flow paths 84, 85, and 86 extend in the axial direction, respectively. The supply flow paths 84, 85, and 86 communicate with flow paths formed in the valve body 72 in the valve body 72.

<Straight>

Hydraulic oil (pressure oil) is supplied from the valve unit 71 to the oil chamber 46 of the left side clutch 41 via the left supply flow path 74 of the side clutch shaft 14. Hydraulic oil is supplied from the valve unit 71 to the oil chamber 58 of the right side clutch 51 via the right supply flow path 75 of the side clutch shaft 14. The hydraulic oil supplied excessively to the oil chambers 46 and 58 is returned to the valve unit 71 via the conveyance flow path 76 of the side clutch shaft 14.

In the state where hydraulic oil is not supplied to the oil chamber 46 of the left side clutch 41, the left engagement body 42 is urged by the spring 43 to the left output gear 31 side, and the left engagement body 42 is carried out. The inner tooth 45 of meshes with the left output gear 31. This state is a latching state of the left side clutch 41. In addition, in the state where hydraulic oil is not supplied to the oil chamber 58 of the right side clutch 51, the right engagement body 52 is urged to the right output gear 32 side by the spring 54, and the right engagement body ( The inner tooth 56 of 52 meshes with the right output gear 32. This state is a latching state of the right side clutch 51.

The power of the sub transmission shaft 13 is transmitted to the side clutch shaft 14 via the straight gear 26 and the side clutch input gear 28. In the engaged state of the left side clutch 41, when the side clutch shaft 14 is rotated by the power transmitted to the side clutch shaft 14, the left engagement body 42 and the left output gear 31 are integrally formed. Rotate Therefore, the power transmitted to the side clutch shaft 14 is transmitted to the left transmission gear 33 through the left engagement body 42 and the left output gear 31, and travels to the left from the left transmission gear 33. Output towards the device. On the other hand, in the engaged state of the right side clutch 51, when the side clutch shaft 14 is rotated by the power transmitted to the side clutch shaft 14, the right engagement body 52 and the right output gear 32 are Rotate integrally Therefore, the power transmitted to the side clutch shaft 14 is transmitted to the right transmission gear 34 via the right engagement body 52 and the right output gear 32, and runs to the right from the right transmission gear 34. Output towards the device. Therefore, in a state where both the left side clutch 41 and the right side clutch 51 are engaged, the constant speed power is transmitted to the left and right traveling apparatus, and the body of the combine moves straight.

<Turn left>

When hydraulic oil is supplied from the valve unit 71 to the oil chamber 46 of the left side clutch 41 through the left supply flow path 74 of the side clutch shaft 14, the piston 44 is moved from the left output gear 31. The left engagement body 42 is pressed against the piston 44 to move in the spaced apart direction, and the engagement of the left output gear 31 and the left engagement body 42 is released. This state is a latch release state of the left side clutch 41. When hydraulic oil is supplied from the left feed passage 74 to the oil chamber 46, the hydraulic oil is also supplied from the left feed passage 74 to the left swing clutch 66, and the left swing clutch 66 is engaged. In the engaged state of the left swing clutch 66, the output relay gear 59 and the left output gear 31 are engaged to rotate integrally.

Since the engagement of the left output gear 31 and the left engagement body 42 has been released, the side clutch shaft 14 is moved from the sub transmission shaft 13 to the side clutch shaft 14 via the straight gear 26 and the side clutch input gear 28. Power transmitted is not transmitted from the left engagement body 42 to the left output gear 31. At this time, when the hydraulic oil is supplied from the valve unit 71 to the soft clutch 62 via the supply flow path 84 of the turning clutch shaft 15, and the soft clutch 62 is in the engaged state, the left engagement body 42 is carried out. Is transmitted to the swing clutch shaft 15 via the soft clutch input gear 61. Then, power is transmitted from the swing clutch shaft 15 to the output relay gear 59 via the swing output gear 65, and the left output gear 31 rotates by the power. That is, the power transmitted to the side clutch shaft 14 is output relay gear 59 via the left engagement body 42, the soft clutch input gear 61, the turning clutch shaft 15, and the turning output gear 65. FIG. Is decelerated and delivered. Thereby, the base body of a combine completes turn to the left direction.

Further, if the spin clutch 64 is in the engaged state from the valve unit 71 through the supply flow path 85 of the swing clutch shaft 15, the swing unit rotates from the sub transmission shaft 13 via the spin clutch input gear 63. Power in the same direction as that transmitted to the side clutch shaft 14 is transmitted to the clutch shaft 15. The power is transmitted from the swing clutch shaft 15 to the output relay gear 59 via the swing output gear 65, and the left output gear 31 rotates by the power. At this time, the rotational direction of the left output gear 31 becomes opposite to the rotational direction of the left output gear 31 when the left side clutch 41 is in the engaged state. Thereby, the base body of a combine rotates supernova in the left direction.

<Right turn>

When hydraulic oil is supplied from the valve unit 71 to the oil chamber 58 of the right side clutch 51 via the right supply flow path 75 of the side clutch shaft 14, the piston 55 is moved from the right output gear 32. The right engagement body 52 is pressed against the piston 55 to move in the spaced apart direction, and the engagement between the right output gear 32 and the right engagement body 52 is released. This state is a latch engagement release state of the right side clutch 51. When hydraulic oil is supplied from the right supply flow path 75 to the oil chamber 58, hydraulic oil is also supplied from the right supply flow path 75 to the right rotation clutch 67, and the right rotation clutch 67 will be in the engaged state. In the engaged state of the right swing clutch 67, the output relay gear 59 and the right output gear 32 are engaged to rotate integrally.

Since the engagement between the right output gear 32 and the right engagement body 52 is released, the side clutch shaft 14 is moved from the sub transmission shaft 13 to the side clutch shaft 14 via the straight gear 26 and the side clutch input gear 28. The transmitted power is not transmitted from the right engagement body 52 to the right output gear 32. At this time, if the hydraulic oil is supplied from the valve unit 71 to the soft clutch 62 via the supply flow path 84 of the turning clutch shaft 15, and the soft clutch 62 is in the engaged state, the right engagement body 52 will be carried out. Is transmitted to the swing clutch shaft 15 via the soft clutch input gear 61. Then, power is transmitted from the swing clutch shaft 15 to the output relay gear 59 via the swing output gear 65, and the right output gear 32 rotates by the power. That is, the power transmitted to the side clutch shaft 14 is output relay gear 59 via the right engagement body 52, the soft clutch input gear 61, the turning clutch shaft 15, and the turning output gear 65. FIG. Is decelerated and delivered. Thereby, the base body of a combine completes turn to the right direction.

Further, if the spin clutch 64 is in the engaged state from the valve unit 71 through the supply flow path 85 of the swing clutch shaft 15, the swing unit rotates from the sub transmission shaft 13 via the spin clutch input gear 63. Power in the same direction as that transmitted to the side clutch shaft 14 is transmitted to the clutch shaft 15. The power is transmitted from the swing clutch shaft 15 to the output relay gear 59 via the swing output gear 65, and the right output gear 32 rotates by the power. At this time, the rotation direction of the right output gear 32 is reverse to the rotation direction of the right output gear 32 when the right side clutch 51 is in the engaged state. Thereby, the base body of a combine spins to the right direction.

<Valve unit>

2 is a left side view of the valve unit 71. FIG. 3: is sectional drawing of the valve unit 71 in the cut surface line A-A shown in FIG.

The valves provided in the valve unit 71 include a relief valve 73 for adjusting the oil pressure in the flow path formed in the valve body 72 to the relief pressure or less. The relief valve 73 is provided with the holder 91, the poppet 92, the adjustment screw 93, and the spring 94. As shown in FIG.

The holder 91 has a normal peripheral wall 95. In the peripheral wall 95, the guide part 96, the small inner diameter part 97, the large inner diameter part 98 in order from one end side (henceforth simply called "one end side") of a center line direction to the other end side in order. And a threaded portion 99 is formed.

The guide part 96 is formed in cylindrical shape. One end of the guide portion 96 may be blocked by a wall integrally formed with the guide portion 96, or may be closed by a plug.

The small inner diameter part 97 is formed in the cylindrical shape which has an inner diameter slightly larger than the inner diameter of the guide part 96. As shown in FIG. A plurality of first connection holes 101 penetrate through the small inner diameter 97.

The large inner diameter 98 is formed in a cylindrical shape having an inner diameter larger than the inner diameter of the small inner diameter 97. In the large inner diameter 98, a plurality of second connection holes 102 are formed. The size of the second connection hole 102 is larger than the size of the first connection hole 101. The end 103 at the screw portion 99 side of the large inner diameter portion 98 has a larger outer diameter than the remaining portion, and a spline extending on the outer circumferential surface of the end portion 103 in the centerline direction of the holder 91. 104 is formed.

The screw portion 99 is formed in a cylindrical shape having the same inner diameter as the large inner diameter portion 98 and an outer diameter larger than the large inner diameter portion 98. The screw is formed in the inner peripheral surface of the screw part 99.

In addition, the portion 105 that extends over the small inner diameter portion 97 and the large inner diameter portion 98 is formed to have the same outer diameter as the outer diameter of the end 103 on the other end side of the large inner diameter portion 98. In this portion 105, a groove 106 is formed over the entire circumference, and the first seal ring 107 is fitted into the groove 106.

In addition, the second seal ring 108 is externally fitted to the other end side of the large inner diameter 98.

The poppet 92 includes a conical valve body 111, and a stem 112 is formed at one end of the valve body 111. On one end side of the stem portion 112, a sliding portion 113 is formed so as to be slidably fitted to the inner circumferential surface of the guide portion 96. In the inner space surrounded by the guide part 96 and the small inner diameter part 97, the primary pressure chamber 114 sandwiched between the valve body part 111 and the sliding part 113 is partitioned.

The adjusting screw 93 is formed in a substantially cylindrical shape, and has a flat cylindrical flange portion 121 having an outer diameter substantially the same as the inner diameter of the large inner diameter portion 98. The groove 122 is formed in the circumferential surface of the flange portion 121 over the entire circumference, and the third seal ring 123 is fitted to the groove 122. The adjustment screw 93 is inserted into the holder 91 from the end of the other end side, and the flange portion 121 is disposed in the space surrounded by the large inner diameter 98. Then, the third seal ring 123 is in liquid sealing contact with the inner circumferential surface of the large inner diameter portion 98, whereby the third seal ring 123 is sandwiched between the valve body 111 of the poppet 92 and the third seal ring 123. The differential pressure chamber 124 is partitioned. A screw is formed in the outer peripheral surface of the other end side edge part of the adjustment screw 93, and this screw is screwed with the screw of the screw part 99 of the holder 91. As shown in FIG. The lock nut 125 is screwed in the part which protruded from the holder 91 of the adjustment screw 93.

The spring 94 is interposed between the poppet 92 and the adjustment screw 93. One end of the spring 94 is supported by the poppet 92, and the other end is supported by the flange portion 121 of the adjustment screw 93. In other words, the flange portion 121 functions as a support portion that supports one end of the spring 94.

The holder 91 is inserted into the holding hole 131 formed in the valve body 72. The spline 132 is formed in the circumferential surface near the inlet of the holding hole 131. When the spline 104 of the holder 91 engages with the spline 132 of the holding hole 131, the holder 91 is provided to the valve body 72 without relative rotation. The first seal ring 107 and the second seal ring 108 are liquid-sealed to the inner circumferential surface of the holding hole 131 with the holder 91 inserted into the deepest position of the holding hole 131. In contact with the holder 91 and the holding hole 131, a pump port 133 is formed at one end with respect to the first seal ring 107, and the first seal ring 107 and the second seal are formed. A tank port 134 is formed between the rings 108. The pump port 133 communicates with the primary pressure chamber 114 in the holder 91 via the first connection hole 101. The tank port 134 communicates with the secondary pressure chamber 124 in the holder 91 via the second connection hole 102. In addition, the pump port 133 and the tank port 134 communicate with a flow path formed in the valve body 72.

When the pressure of the hydraulic oil introduced into the primary pressure chamber 114 through the pump port 133 and the first connection hole 101 from the flow path is smaller than the pressure (releasing pressure) corresponding to the elastic force of the spring 94, the valve body portion The 111 seats on the valve seat 135 formed by the step between the inner circumferential surface of the small inner diameter portion 97 and the inner circumferential surface of the large inner diameter portion 98 so that the relief valve 73 maintains the valve closed state.

When the hydraulic pressure in the primary pressure chamber 114 rises and the hydraulic pressure becomes larger than the pressure corresponding to the elastic force of the spring 94, the poppet 92 moves to the other end side in response to the elastic force of the spring 94, and the valve body portion ( 111 is spaced apart from the valve seat 135. As a result, hydraulic oil flows from the primary pressure chamber 114 into the secondary pressure chamber 124 and flows out from the secondary pressure chamber 124 to the tank port 134 through the second connection hole 102. Thereby, the oil pressure in the flow path connected to the pump port 133 is adjusted to below relief pressure.

Since the elastic force of the spring 94 can be adjusted by changing the screw insertion depth of the adjustment screw 93, the relief pressure corresponding to the elastic force of the spring 94 can be adjusted.

<Action effect>

As described above, the relief valve 73 is provided with the holder 91 in which the valve seat 135 which receives the poppet 92 is formed. In the conventional structure which is not equipped with this holder 91, the valve seat which supports the poppet 92 is formed in the valve body 72. As shown in FIG. The valve body 72 is made of aluminum, for example, and cast by die casting. Therefore, there exists a problem that the fluctuation | variation of the processing precision of a valve seat (seat surface) is large, and also time-dependent deterioration, such as abrasion of a valve seat, arises and a relief pressure is not stabilized. By using the holder 91 in which the valve seat 135 of the poppet 92 is integrally formed, the seat surface can be stabilized both in terms of initial performance and durability, and the relief pressure can be stabilized. By increasing the stability of the relief pressure, the behavior variation of the power transmission device 1 can be reduced. In addition, it is easy to adjust the relief pressure, and the fluctuation of the relief pressure at the time of factory shipment of the power transmission device 1 or the work vehicle equipped with the same can be reduced.

Moreover, the mounting part 103 provided in the valve body 72 is formed in the holder 91. As shown in FIG. Therefore, after assembling the poppet 92, the adjusting screw 93, and the spring 94 to the holder 91 and subassembly, the mounting portion 103 is attached to the valve body 72, The relief valve 73 can be assembled to the valve body 72. Therefore, the relief pressure can be set and adjusted in the state of the subassembly, and further improvement of the stability of the relief pressure can be achieved.

In the peripheral wall 95 of the holder 91, a guide portion 96 for guiding the movement of the poppet 92 is formed. In the configuration in which hydraulic oil (relief oil) flows along the surface guiding the movement of the poppet 92, the area of the flow path through which hydraulic oil flows rapidly changes with respect to the lift amount of the poppet 92. On the other hand, by providing the guide part 96 independent of the valve seat 135, the rapid change of the area of the flow path through which hydraulic oil flows with respect to the lift amount of the poppet 92 can be suppressed.

The adjustment screw 93 is integrally formed with the flange portion 121 as a support portion that supports one end of the spring 94. Thereby, since it is not necessary to form a support part as a separate part, the number of parts can be reduced and the number of assembly processes can be reduced.

The adjusting screw 93 is screwed into the holder 91. When the spline 104 of the holder 91 engages with the spline 132 of the holding hole 131, the holder 91 is attached to the valve body 72 without relative rotation. Thereby, when the adjustment screw 93 is screwed into the holder 91, it can suppress that the holder 91 comes with the adjustment screw 93 and rotates. Therefore, the adjustment screw 93 can be operated favorably, and the adjustment work of a relief pressure becomes easy.

In addition, in the power transmission device 1, the side clutch shaft 14 extends into the valve body 72, and the left supply flow path 74, the right supply flow path 75 formed in the side clutch shaft 14, and The conveyance flow path 76 communicates with the flow path in the valve body 72. Therefore, the seal ring 81 is provided in the transmission side rather than each communication site | part of the left supply flow path 74, the right supply flow path 75, and the conveyance flow path 76, and the seal ring 81 is a valve body. By sealingly contacting 72 with liquid, it is possible to seal between the side clutch shaft 14 and the valve body 72.

In the configuration in which the seal rings 81, 82, 83 are provided in the valve unit 71, the problem of the seal rings 81, 82, 83 can be detected in the state of the valve unit 71 alone, and the occurrence of the problem Cause identification and replacement of the seal rings 81, 82, and 83 are easy. Therefore, the loss time in a manufacturing process can be made small, and manufacturing quality can be improved and stabilized.

<Variation example>

As mentioned above, although embodiment of this invention was described, this invention can also be implemented with other aspects.

For example, in the above-mentioned embodiment, although the power transmission device 1 is mounted in a combine, it is not limited to a combine, but works other than a combine, such as a harvester which harvests vegetables, such as ginseng, a radish, green beans, and cabbage, The power transmission device 1 may be mounted in the vehicle.

In addition, in the above-described configuration, various design changes can be made within the scope of the matters described in the claims.

1: power train
14: side clutch shaft
41: left side clutch
51: right side clutch
71: valve unit
72: valve body
73: relief valve
74: left supply flow path
75: Wu supply euro
76: return flow path
77, 78: communication site
81, 82, 83: seal ring
91: holder
92: poppet
93: adjustment screw
94: spring
95: surrounding wall
96: guide
101: first connection hole
102: second connection hole
103: mounting portion
107: first seal ring (annular seal)
108: second seal ring (annular seal)
121: flange part (support part)
133: pump port
134: tank port
135: valve seat

Claims (10)

A transmission including a transmission having a clutch operated by hydraulic pressure, and a valve unit having a valve body and a valve provided in the valve body,
The valve includes a relief valve for adjusting the hydraulic pressure in the flow path formed in the valve body to below the relief pressure,
The relief valve,
A holder having a normal peripheral wall,
A poppet received in the holder and provided to be movable in a direction of the center line of the holder;
An adjusting member inserted into the holder from one side in the center line direction;
A spring interposed between the poppet and the adjustment member to press the poppet to the other side opposite to the one side in the centerline direction,
The installation part provided in the said valve body is formed in the outer peripheral surface of the said holder, The power transmission apparatus in which the valve seat which receives the poppet is formed in the inner peripheral surface. The power transmission device according to claim 1, wherein a guide portion for guiding movement of the poppet is formed on the peripheral wall of the holder. The said circumferential wall of the said holder, The 1st connection hole and the 2nd connection hole are respectively penetrated and formed in the position spaced apart in the said centerline direction,
The relief valve is externally fitted to the circumferential wall between the first connection hole and the second connection hole, and liquid-tightly abuts against the valve body, thereby providing a space between the valve body and the circumferential wall. The power transmission device further provided with the annular seal partitioned by the pump port through which a 1st connection hole communicates, and the tank port with which the 2nd connection hole communicates. The power transmission device according to claim 1 or 2, wherein a support portion that supports one end of the spring is integrally formed on the adjustment member. The said mounting part is provided in the said valve body so that relative rotation is impossible,
And the adjusting member is an adjusting screw screwed into the holder. It is a power transmission device having a clutch operated by hydraulic pressure, and a transmission for transmitting power to the left and right traveling device, and a valve unit having a valve body and a valve provided in the valve body,
In the clutch,
A left side clutch which engages and engages with the left transmission gear for transmitting power transmitted to the side clutch shaft to the traveling device on the left;
A right transmission clutch for transmitting power transmitted to the side clutch shaft to the traveling device on the right side and a right side clutch for engaging and releasing engagement;
The side clutch shaft includes a left supply flow path for supplying hydraulic oil to the left side clutch, a right supply flow path for supplying hydraulic oil to the right side clutch, and hydraulic oil supplied excessively to the left side clutch and the right side clutch. The conveying flow path to be conveyed is formed extending in the axial direction, respectively,
The left supply flow passage, the right supply flow passage and the transfer passage communicate with a flow passage formed in the valve body in the valve body,
The power transmission device provided with the sealing ring which seals between the said side clutch shaft and the said valve body in the said transmission side rather than each communication site | part of the said left supply flow path, the said right supply flow path, and the said conveyance flow path and the said flow path. The power transmission device according to claim 3, wherein the adjustment member is integrally formed with a support portion that supports one end of the spring. The said installation part is provided in the said valve body so that relative rotation is impossible,
And the adjusting member is an adjusting screw screwed into the holder. The said mounting part is provided in the said valve body so that relative rotation is impossible,
And the adjusting member is an adjusting screw screwed into the holder. The said mounting part is provided in the said valve body so that relative rotation is impossible,
And the adjusting member is an adjusting screw screwed into the holder.

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