阅读说明：本技术 动力传递装置、变速装置及固定结构 (Power transmission device, and fixing structure ) 是由 法田诚二 木曾田雄星 于 2019-06-25 设计创作，主要内容包括：本发明提供一种动力传递装置、变速装置及固定结构。所述动力传递装置可以实现结构的简化的动力传递装置。在工作油没有流入油路(38、62)的状态下,利用弹簧(43)的弹性力,按压部件(41)向停车制动器(28)侧被施力,按压部件(41)的作用部(42)按压离合器板(27)。由此,离合器盘(25)与离合器板(27)被压接,停车制动器(28)卡合,第一轴(11)被制动。另外,其按压力经由共用部件(21)传递到双轴结合离合器(33),离合器板(31)以及离合器盘(32)被压接。由此,双轴结合离合器(33)卡合,第一轴(11)与第二轴(12)结合。(The invention provides a power transmission device, a transmission device and a fixing structure. The power transmission device can realize a power transmission device with a simplified structure. When the hydraulic oil does not flow into the oil passages (38, 62), the pressing member (41) is biased toward the parking brake (28) by the elastic force of the spring (43), and the operating portion (42) of the pressing member (41) presses the clutch plate (27). Thus, the clutch disc (25) and the clutch plate (27) are pressed against each other, the parking brake (28) is engaged, and the first shaft (11) is braked. The pressing force is transmitted to the double-shaft coupling clutch (33) via the common member (21), and the clutch plate (31) and the clutch disc (32) are pressed against each other. Thus, the double shaft coupling clutch (33) is engaged, and the first shaft (11) and the second shaft (12) are coupled.)

1. A power transmission device that transmits power to a running device, wherein the power transmission device comprises:

a first clutch engaged/released for braking/releasing the first shaft;

a second clutch engaged/released for engaging/disengaging the first shaft with/from a second shaft; and

a pressing member that presses and engages one of the first clutch and the second clutch,

the first clutch and the second clutch are disposed on the same axis, and when one of the first clutch and the second clutch is pressed by the pressing member, the pressing force is transmitted to the other of the first clutch and the second clutch.

2. The power transmission device according to claim 1,

the power transmission device further includes an elastic member,

the pressing member presses the first clutch by an elastic force of the elastic member.

3. The power transmission device according to claim 2,

the power transmission device further includes an oil chamber to which pressure oil for disengaging the pressing member from the first clutch against an elastic force of the elastic member is supplied.

4. The power transmission device according to claim 2 or 3,

the power transmission device further includes a moving member provided movably in a first direction in which the pressing member approaches the first clutch and a second direction in which the pressing member separates from the first clutch,

the moving member moves in the second direction from a state in which the first clutch is engaged, the moving member presses the pressing member, and the pressing member moves against the elastic force of the elastic member to release the first clutch.

5. The power transmission device according to claim 4,

the power transmission device further includes a housing,

the moving member has a cylindrical portion inserted through an insertion hole formed in the housing,

a screw thread is formed on a portion of the cylindrical portion protruding to the outside of the housing,

the moving member is moved in the second direction by fastening a bolt screwed to the thread of the columnar portion to the outside of the housing.

6. A power transmission device that transmits power to a running device, wherein the power transmission device comprises:

a parking brake that is engaged/released to brake/release a first rotating body that connects the traveling device and a power transmission path;

an elastic member;

a pressing member that presses and engages the parking brake by an elastic force of the elastic member;

a moving member provided to be movable in a first direction in which the pressing member approaches the parking brake and a second direction in which the pressing member moves away from the parking brake; and

a shifter that moves to a drive position where the second rotating body and the third rotating body are integrally rotatably coupled and a neutral position where the coupling is released, in conjunction with the movement of the moving member,

the moving member moves in the second direction from a state where the parking brake is engaged, the moving member presses the pressing member, the pressing member moves against the elastic force of the elastic member, the parking brake is released, and the shifter moves from the drive position to the neutral position.

7. The power transmission device according to claim 6,

an oil chamber is formed between the pressing member and the moving member,

the hydraulic pressure is supplied to the oil chamber from a state in which the parking brake is engaged, and the pressing member moves against the elastic force of the elastic member, thereby releasing the parking brake.

8. The power transmission device according to claim 6 or 7,

the power transmission device further includes a housing,

the moving member has a cylindrical portion inserted through an insertion hole formed in the housing,

a screw thread is formed on a portion of the cylindrical portion protruding to the outside of the housing,

the moving member is moved in the second direction by fastening a bolt screwed to the thread of the columnar portion to the outside of the housing.

9. The power transmission device according to any one of claims 6 to 8,

the third rotating body is the first rotating body.

10. A transmission device that changes a speed of power of a drive source and transmits the power to right and left traveling devices, comprising:

a left and a right power transmission mechanisms provided corresponding to each of the left and the right travel devices, each of the left and the right power transmission mechanisms including a transmission gear for transmitting power from the drive source and a shift gear provided to be movable in a rotational axis direction of the transmission gear, wherein a power transmission path is formed by engagement between the transmission gear and the shift gear, and the power transmission path is cut by moving the shift gear in one of the rotational axis directions to release the engagement between the transmission gear and the shift gear;

a shift member provided movably in the rotation axis direction and including shift forks coupled to the left and right shift gears, respectively; and

an urging member that urges the shift member in another direction opposite to the one direction of the rotation axis direction.

11. The transmission device according to claim 10,

the transmission device further includes a unit case housing the power transmission mechanism,

the shift member includes a shift fork shaft that supports the left and right shift forks, and the shift fork shaft extends in the rotation axis direction and is held in the unit case so as to be movable in the rotation axis direction.

12. The transmission device according to claim 11,

one end portion of the shift rail extends through the unit housing to the outside,

the transmission device further includes an operating member that is connected to the one end portion of the shift rail and moves the shift rail in the rotational axis direction by a turning operation with a support shaft extending in a direction orthogonal to the rotational axis direction as a fulcrum.

13. The transmission device according to claim 12,

the operation member includes: a shift operating piece supported by the support shaft and connected to the shift fork shaft, and an operating arm supported by the support shaft and rotated integrally with the shift operating piece,

the distance from the support shaft to the tip end of the operating arm is greater than the distance from the support shaft to the connecting portion between the shift operating piece and the shift rail.

14. The transmission device according to claim 13,

an engaging portion that engages the operating arm in a state where the engagement of the transmission gear and the shift gear is released is formed in the unit case.

15. The transmission device according to any one of claims 11 to 14,

the urging member is interposed between the unit case and one of the left and right shift forks.

16. The transmission according to any one of claims 10 to 15,

an annular groove portion centered on the rotational axis of the transmission gear is formed on a side surface of the transmission gear,

a plurality of internal teeth that protrude toward the rotation axis are formed on the outer circumferential surface of the groove portion so as to be aligned in the circumferential direction of the groove portion,

the shift gear includes a plurality of external teeth protruding outward in a rotational radial direction, and is engaged with the transmission gear by the external teeth being fitted in tooth grooves between adjacent internal teeth of the transmission gear.

17. A fixing structure for fixing an axle box housing an axle of a work vehicle,

the axle box integrally includes a cylindrical portion through which the axle is inserted and a fixing portion extending outward in a radial direction of the axle from the cylindrical portion,

the fixing portion is fixed to a frame of the work vehicle.

18. The fixation structure of claim 17,

the work vehicle is provided with a power transmission mechanism for transmitting power to the axle and a main body case for housing the power transmission mechanism,

a cylindrical insertion portion extending in an axial direction of the axle and through which the axle is inserted is formed in the main body case,

the cylindrical portion of the axle box is inserted into the insertion portion without being fixed to the insertion portion.

Technical Field

A first aspect of the invention relates to a power transmission device that transmits power.

The second aspect of the invention also relates to a power transmission device that transmits power.

The third aspect of the present invention relates to a transmission for a work vehicle such as a combine harvester.

A fourth aspect of the present invention relates to a fixing structure of an axle box that houses an axle of a work vehicle.

Background

In the first aspect, for example, some work vehicles such as combine harvesters employ crawler belts for a pair of left and right traveling devices. In the work vehicle using this crawler belt, in order to turn the machine body left and right, it is necessary to change the speed of the power transmitted to the left and right crawler belts. For example, when power having a lower speed than power transmitted to one crawler belt is transmitted to the other crawler belt, the machine body slowly turns toward the other crawler belt. Further, by transmitting power in the opposite direction to the power transmitted to one crawler belt to the other crawler belt, the machine body turns in situ to the other crawler belt side.

In order to change the speed of power and switch the transmission path, a power transmission device for transmitting power to right and left crawler belts is provided with a plurality of clutches. In the configuration including a plurality of clutches, a configuration in which the clutches are operated by hydraulic pressure is generally provided for each clutch. However, since the clutch must be operated by a mechanical method rather than a hydraulic pressure in the operation of the parking brake for maintaining the stopped state of the machine body, for example, when the parking brake is operated by the braking of the first shaft and the coupling of the first shaft and the second shaft, a structure is required in which these clutches are mechanically operated for each of the clutch (brake) for braking the first shaft and the clutch for coupling the first shaft and the second shaft. Therefore, the structure of the power transmission device is complicated and large.

Prior art documents

Patent document

Patent document 1: japanese patent laid-open publication No. 2018-3916

In the second aspect, for example, in the combine harvester, the power of the drive source is transmitted to the pair of left and right running devices via the power transmission device.

The power transmission device is provided with a parking brake for maintaining a stopped state of the machine body. The shaft or gear included in the power transmission device is braked, for example, by the operation of the parking brake. Then, the braking force reaches the left and right traveling devices, and the stopped state of the machine body is maintained.

Some of the combine harvesters include a power transmission device provided with a mechanical sub-transmission mechanism. In the sub-transmission mechanism, the shifter is spline-coupled to the two gears at a position straddling the two gears, and is in a driving state in which power is transmitted between the gears. When the spline coupling of the shifter to one gear is released, power is not transmitted between the two gears, and therefore, a neutral state is achieved in which power is not transmitted to the traveling device.

Prior art documents

Patent document

Patent document 2: japanese patent laid-open publication No. 2012-62973

Conventionally, a parking brake and a sub-transmission mechanism are provided with operating mechanisms for operation, respectively. Therefore, the power transmission device including the parking brake and the sub-transmission mechanism is complicated in structure, and therefore, when the sub-transmission mechanism is used less frequently in the neutral state, the structure is significantly wasted.

In a third aspect, for example, in a combine equipped with an HST (hydrostatic Transmission), a hydraulic pump of the HST is driven by power of an engine, and a hydraulic motor is driven by oil discharged from the hydraulic pump. The power of the hydraulic motor is transmitted to the left and right crawler belts via a power transmission mechanism including gears. The left and right crawler belts are driven at the same speed, whereby the machine body moves straight forward and backward, and the left and right crawler belts are driven at a speed difference, whereby the machine body turns left and right.

Prior art documents

Patent document

Patent document 2: japanese patent laid-open publication No. 2012-62973

In a combine harvester, in order to perform adjustment, traction in an emergency, and the like, it is necessary to change the speed to a neutral state in which power is not transmitted between the hydraulic motor of the HST and the left and right crawler belts. The neutral state can be generated by, for example, releasing the engagement of two gears of the power transmission mechanism included between the hydraulic motor and the left crawler belt and the power transmission mechanism included between the hydraulic motor and the right crawler belt.

However, in the case of the structure in which the engagement of the gears is released independently in the right and left power transmission mechanisms, the mechanisms for the engagement and release of the engagement need to be independent from each other, resulting in an increase in the size of the transmission including the power transmission mechanisms. Further, when two gears are meshed from a neutral state, the gears are not meshed, that is, the tooth grooves of one gear and the tooth grooves of the other gear are not opposed to each other in the rotation axis direction.

With regard to the fourth aspect, for example, in a combine harvester, since uneven ground passing capability is required, a pair of left and right traveling devices employ crawler belts. The axle is connected to a sprocket as a driving wheel of the crawler belt so as not to rotate relatively. Then, power from the drive source is transmitted to the left and right axles via the power transmission mechanism, and the drive wheels of the left and right crawler belts rotate integrally with the axles, respectively.

Fig. 8 is a sectional view showing a structure in the vicinity of an axle in a conventional combine harvester.

The end portion of the axle 51 on the vehicle width direction inner side is inserted into a main body case 52 that houses the power transmission mechanism, and is coupled to the gear 53 in the main body case 52 so as not to be relatively rotatable. The end portion of the axle 51 on the outer side in the vehicle width direction is coupled to the sprocket 54 so as not to be relatively rotatable.

The axle 51 is covered by an axle box 55 between the main body case 52 and the sprocket 54. The axle box 55 includes: a cylindrical housing body portion 56, and a flange portion 57 extending outward in the rotational radial direction of the axle 51 from an end portion of the housing body portion 56 on the main body housing 52 side. The case main body portion 56 and the flange portion 57 are fixed to each other by welding. The flange 57 abuts against the outer surface of the body case 52, and the axle box 55 is fixed to the body case 52 by screwing the tip end of the bolt 58 inserted through the flange 57 into the body case 52.

Prior art documents

Patent document

Patent document 3: japanese laid-open patent publication No. 2009-78699

In this configuration, when a large load (lateral tensile load) in the radial direction is applied to the sprocket 54, a load in the direction in which the bolt 58 is disengaged is applied to the fastening portion between the flange portion 57 of the axle box 55 and the main body case 52 fastened by the bolt 58. As a result, there is a possibility that oil leakage occurs or the main body case 52 is damaged due to the damage of the gasket 59 for sealing between the main body case 52 and the axle box 55.

Disclosure of Invention

An object of a first aspect of the present invention is to provide a power transmission device that can achieve simplification of the structure.

In order to achieve the above object, a power transmission device of the present invention transmits power to a running device, wherein the power transmission device includes: a first clutch engaged/released for braking/releasing the first shaft; a second clutch engaged/released for engaging/disengaging the first shaft with/from the second shaft; and a pressing member that presses and engages one of the first clutch and the second clutch, wherein the first clutch and the second clutch are disposed on the same axis, and when one of the first clutch and the second clutch is pressed by the pressing member, the pressing force is transmitted to the other of the first clutch and the second clutch.

According to this configuration, when one of the first clutch and the second clutch is pressed by the pressing member and engaged, the pressing force is transmitted to the other of the first clutch and the second clutch. Thereby, both the first clutch and the second clutch are engaged. Therefore, the need to provide a mechanism for operating the first clutch and the second clutch for each clutch can be eliminated, and the structure can be simplified.

The power transmission device may further include an elastic member, and the pressing member may press the first clutch by an elastic force of the elastic member.

The power transmission device may further include a moving member that is provided so as to be movable in a first direction in which the pressing member approaches the first clutch and a second direction in which the pressing member separates from the first clutch, the moving member moving from a state in which the first clutch is engaged to the second direction, the moving member pressing the pressing member, and the pressing member moving against the elastic force of the elastic member to release the first clutch.

The power transmission device may have the following structure: the movable member has a cylindrical portion inserted into an insertion hole formed in the housing, a screw thread is formed in a portion of the cylindrical portion protruding to the outside of the housing, and the movable member is moved in the second direction by fastening a bolt screwed to the screw thread of the cylindrical portion to the outside of the housing. According to this configuration, the position of the moving member is determined by the amount of tightening of the nut, and therefore, the position of the moving member can be adjusted with high accuracy.

According to the present invention, simplification of the structure can be achieved.

A second aspect of the present invention is directed to a power transmission device that can simplify a structure including a parking brake and a sub-transmission mechanism.

In order to achieve the above object, a power transmission device of the present invention transmits power to a running device, wherein the power transmission device includes: a parking brake that is engaged/released to brake/release a first rotating body that connects the traveling device and the power transmission path; an elastic member; a pressing member that presses and engages the parking brake by an elastic force of the elastic member; a moving member provided to be movable in a first direction in which the pressing member approaches the parking brake and a second direction in which the pressing member moves away from the parking brake; and a shifter that moves to a drive position where the second rotating body and the third rotating body are integrally rotatably coupled and a neutral position where the coupling is released in conjunction with the movement of the moving member, wherein the moving member moves in the second direction from a state where the parking brake is engaged, the moving member presses the pressing member, the pressing member moves against the elastic force of the elastic member, the parking brake is released, and the shifter moves from the drive position to the neutral position.

According to this configuration, the pressing member is always urged toward the parking brake by the elastic force of the elastic member, the parking brake is engaged by the pressing of the pressing member, and the first rotating body is braked. When the moving member moves from this state in the second direction, the moving member presses the pressing member, and the pressing member moves in the second direction against the elastic force of the elastic member, so that the parking brake is released, and the brake of the first rotating body is released. Therefore, an operation lever or the like for operating (engaging) the parking brake is not required, and the parking brake and the operation lever or the like do not need to be mechanically connected, so that the degree of freedom in layout of the components constituting the power transmission device is improved.

When the parking brake is released, the shifter moves from the drive position to the neutral position in conjunction with the movement of the moving member, and the second rotating body and the third rotating body are decoupled from each other. Therefore, an operation mechanism including an operation lever or the like is not required in the sub-transmission mechanism including the shifter, and therefore, the structure of the power transmission device can be simplified.

An oil chamber may be formed between the pressing member and the moving member, and a hydraulic pressure may be supplied to the oil chamber from a state in which the parking brake is engaged, and the pressing member may be moved against an elastic force of the elastic member to release the parking brake.

The power transmission device may have the following structure: the movable member has a cylindrical portion inserted into an insertion hole formed in the housing, a screw thread is formed in a portion of the cylindrical portion protruding to the outside of the housing, and the movable member is moved in the second direction by fastening a bolt screwed to the screw thread of the cylindrical portion to the outside of the housing. According to this configuration, the position of the moving member is determined by the amount of tightening of the nut, and therefore, the position of the moving member can be adjusted with high accuracy.

The third rotating body may be the first rotating body.

According to the present invention, the structure including the parking brake and the sub-transmission mechanism can be simplified.

A third aspect of the present invention is to provide a transmission device in which gear engagement and disengagement in right and left power transmission mechanisms can be switched by one mechanism common to both the right and left sides, and the gear engagement can be satisfactorily achieved.

In order to achieve the above object, a transmission device according to the present invention is a transmission device for transmitting power of a drive source to right and left traveling devices while changing the speed, the transmission device including: a left and a right power transmission mechanisms provided corresponding to each of the left and the right traveling devices, each of the left and the right power transmission mechanisms including a transmission gear for transmitting power from a drive source and a shift gear provided to be movable in a rotational axis direction of the transmission gear, the power transmission mechanism forming a power transmission path by engagement of the transmission gear with the shift gear, and the power transmission mechanism cutting the power transmission path by moving the shift gear in one of the rotational axis directions to release the engagement of the transmission gear with the shift gear; a shift member provided movably in a rotation axis direction and including shift forks coupled to left and right shift gears, respectively; and an urging member that urges the shift member in the other direction opposite to the one direction of the rotation axis direction.

According to this configuration, the power transmission mechanism is provided corresponding to each of the left and right traveling devices. Each power transmission mechanism includes: a transmission gear that transmits power from a drive source, and a shift gear that is provided so as to be movable in a rotational axis direction of the transmission gear. In each power transmission mechanism, a power transmission path for transmitting power to the running device is formed by engagement of the transmission gear and the shift gear. When the shift gear is moved in one direction of the rotation axis direction from a state where the transmission gear is engaged with the shift gear, the engagement between the transmission gear and the shift gear is released, and the power transmission path is cut off. Thus, the transmission is in a neutral state in which power is not transmitted to the right and left traveling devices.

The shift fork of the shift component is combined with the left and right shift gears. The shift member is provided to be movable in the rotational axis direction, and is biased in the other direction opposite to the one direction of the rotational axis direction by a biasing member. When the shift member moves in one direction of the rotation axis direction against the biasing force, the left and right shift gears move in one direction in both directions, and the engagement between the left and right transmission gears and the shift gear is released. When the force for moving the shift member in one direction is released, the shift member is moved in the other direction of the rotation axis direction by the biasing force of the biasing member. If the teeth of the shift gear and the tooth grooves of the transfer gear face each other in the rotational axis direction, the teeth of the shift gear enter the tooth grooves of the transfer gear by the movement of the shift member, and the engagement of the transfer gear and the shift gear is achieved. On the other hand, when the teeth of the shift gear and the tooth grooves of the transmission gear do not face each other in the rotation axis direction, the teeth of the shift gear abut against the teeth of the transmission gear by the movement of the shift member, and the shift gear and the transmission gear do not mesh with each other. Since the shift member is biased in the other direction of the rotation axis direction, even if the teeth of the shift gear come into contact with the teeth of the transmission gear, when the teeth grooves of the transmission gear and the teeth of the shift gear face each other in the rotation axis direction by the rotation of the transmission gear, the teeth of the shift gear enter the teeth grooves of the transmission gear, and the engagement between the transmission gear and the shift gear is achieved.

Therefore, the gear engagement (engagement between the transmission gear and the shift gear) and the engagement release in the right and left power transmission mechanisms can be switched by one mechanism common to the right and left, and the gear engagement can be satisfactorily achieved.

The transmission device may further include a unit case that houses the power transmission mechanism, and the shift member may include a shift rail that supports left and right shift forks, the shift rail extending in the rotation axis direction and being held in the unit case so as to be movable in the rotation axis direction.

In this case, it is preferable that one end portion of the shift rail extends to the outside through the unit case, and the transmission further includes an operating member that is connected to the one end portion of the shift rail and moves the shift rail in the rotation axis direction by a turning operation with a support shaft extending in a direction orthogonal to the rotation axis direction as a fulcrum. The gear engagement and disengagement can be realized by the rotational operation of the operating member.

The operation member may include: in this case, it is preferable that the length from the support shaft to the tip end of the operating arm is greater than the length from the support shaft to the connecting portion between the shift operating piece and the shift rail. Thus, the lever principle works, and even if the force applied to the operating arm is small, the shift rail can be moved well against the biasing force of the biasing member.

Preferably, the unit case is provided with a locking portion for locking the operating arm in a state where the engagement between the transmission gear and the shift gear is released. After the engagement between the transmission gear and the shift gear is released, the operation arm is locked to the locking portion, so that the released state of the engagement can be maintained.

The biasing member is preferably interposed between the unit case and one of the left and right shift forks. Thus, it is not necessary to separately provide a portion for coupling the biasing member and the shift member, and the structure of the shift member can be simplified.

The following structure is also possible: an annular groove portion centered on the rotation axis of the transmission gear is formed in a side surface of the transmission gear, a plurality of internal teeth protruding toward the rotation axis are formed in a circumferential surface on an outer circumferential side of the groove portion in a circumferential direction of the groove portion, the shift gear includes a plurality of external teeth protruding outward in the rotation radial direction, and the external teeth are fitted into tooth grooves between adjacent internal teeth of the transmission gear to mesh with the transmission gear.

According to the present invention, the gear engagement and the gear disengagement in the right and left power transmission mechanisms can be switched by one mechanism common to the right and left, and the gear engagement can be satisfactorily achieved.

A fourth aspect of the present invention is directed to provide a fixing structure of an axle box that can suppress damage to a main body case and the like even when a large lateral tensile load is applied to a sprocket.

In order to achieve the above object, an axle box fixing structure according to the present invention is a structure for fixing an axle box that houses an axle of a work vehicle, wherein the axle box integrally includes a cylindrical portion through which the axle is inserted and a fixing portion that extends outward in a radial direction of the axle from the cylindrical portion, and the fixing portion is fixed to a frame of the work vehicle.

According to this configuration, since the axle box is fixed to the frame of the work vehicle, even when a large lateral tensile load is applied to the drive wheels coupled to the axle, damage to the main body case or the like housing the power transmission mechanism that transmits power to the axle can be suppressed.

The work vehicle may be provided with a power transmission mechanism that transmits power to the axle and a main body case that houses the power transmission mechanism, the main body case may be provided with a tubular insertion portion that extends in the axial direction of the axle and through which the axle is inserted, and the tubular portion of the axle box may be inserted into the insertion portion without being fixed to the insertion portion.

According to the present invention, even when a large lateral tensile load is applied to the sprocket, breakage of the main body case and the like can be suppressed.

Drawings

First embodiment

Fig. 1A is a cross-sectional view showing the configuration of a main part of a power transmission device according to an embodiment of the present invention, and shows a state where a parking brake and a double shaft coupling clutch are engaged.

Fig. 1B is a cross-sectional view showing the configuration of a main part of the power transmission device according to the embodiment of the present invention, and shows a state in which the parking brake and the double shaft coupling clutch are released by hydraulic pressure.

Fig. 1C is a cross-sectional view showing the configuration of a main part of the power transmission device according to the embodiment of the present invention, showing a state where the parking brake is released and the double shaft coupling clutch is engaged.

Fig. 1D is a sectional view showing the configuration of a main part of the power transmission device according to the embodiment of the present invention, and shows a state where the parking brake and the double-shaft coupling clutch are released.

Second embodiment

Fig. 2A is a cross-sectional view showing the configuration of a main part of the power transmission device according to the embodiment of the present invention, and shows a state where a parking brake is engaged.

Fig. 2B is a cross-sectional view showing the configuration of a main part of the power transmission device according to the embodiment of the present invention, and shows a state in which the hydraulic oil is supplied to the oil chamber in order to release the parking brake.

Fig. 2C is a sectional view showing the configuration of a main part of the power transmission device according to the embodiment of the present invention, and shows a state where the parking brake is released and the shifter is located at the neutral position.

Third embodiment

Fig. 3 is a right side view showing a front portion of a combine harvester on which a transmission according to an embodiment of the present invention is mounted.

Fig. 4 is a view showing a partial structure of the transmission.

Fig. 5 is a cross-sectional view showing a part of the transmission, and shows a configuration from the hydraulic motors of the left side HST and the right side HST to the middle of the travel device.

Fig. 6A is a cross-sectional view showing the structure of the neutral transmission mechanism, showing a state in which the second left intermediate gear is engaged with the left shift gear and the second right intermediate gear is engaged with the right shift gear.

Fig. 6B is a cross-sectional view showing the configuration of the neutral transmission mechanism, and shows a state in which the engagement between the second left intermediate gear and the left shift gear is released and the engagement between the second right intermediate gear and the right shift gear is released.

Fig. 6C is a cross-sectional view showing the configuration of the neutral transmission mechanism, showing a state in which the engagement between the second left intermediate gear and the left shift gear is released and the second right intermediate gear and the right shift gear are in contact with each other.

Fig. 6D is a cross-sectional view showing the configuration of the neutral transmission mechanism, showing a state in which the second left intermediate gear abuts against the left shift gear and the second right intermediate gear meshes with the right shift gear.

Fourth embodiment

Fig. 7 is a sectional view showing a structure in the vicinity of an axle of a combine harvester according to an embodiment of the present invention.

Fig. 8 is a sectional view showing a structure in the vicinity of an axle in a conventional combine harvester.

Description of the reference numerals

First embodiment

1: power transmission device

11: first shaft

12: second shaft

28: parking brake (first clutch)

33: double-shaft combined clutch (second clutch)

41: pressing component

43: spring (elastic component)

51: moving part

55: plug-in hole

58: nut

Second embodiment

1: power transmission device

11: first gear (first rotating body, third rotating body)

14: shell body

18: parking brake

21: pressing component

23: spring

31: moving part

35: plug-in hole

36: screw thread

37: nut

43: oil chamber

51: second gear (second rotating body)

54: gear shifter

Third embodiment

12: traveling device

32: speed changing device

112L: second left intermediate gear (transfer gear)

112R: second right intermediate gear (transfer gear)

113L, 113R: trough part

114L, 114R: internal tooth

115L: left shifting gear

115R: right shift gear

116L, 116R: external tooth

120: neutral gear speed change mechanism

121: shifting fork shaft

122L: left shifting fork

122R: right shift fork

125: shift operation piece

126: operating projection

127: supporting axle

128: operating arm

129: spring (force application component)

132: locking convex part (locking part)

Fourth embodiment

12: traveling device

32: speed changing device

112L: second left intermediate gear (transfer gear)

112R: second right intermediate gear (transfer gear)

113L, 113R: trough part

114L, 114R: internal tooth

115L: left shifting gear

115R: right shift gear

116L, 116R: external tooth

120: neutral gear speed change mechanism

121: shifting fork shaft

122L: left shifting fork

122R: right shift fork

125: shift operation piece

126: operating projection

127: supporting axle

128: operating arm

129: spring (force application component)

132: locking convex part (locking part)

Detailed Description

First embodiment

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

< Power Transmission device >

Fig. 1A, 1B, 1C, and 1D are sectional views showing the configuration of main parts of a power transmission device 1 according to an embodiment of the present invention.

The power transmission device 1 is mounted on, for example, a combine harvester, and transmits power to the left and right traveling devices. The combine may be configured to include a 2-pump 2 motor of an HST (hydrostatic Transmission) corresponding to each of the left and right traveling devices, or may be configured to include an HST in common in the left and right traveling devices.

The power transmission device 1 includes a first shaft 11 and a second shaft 12. The first shaft 11 is formed in a cylindrical shape. The second shaft 12 is formed in a cylindrical shape. The first shaft 11 is inserted into the second shaft 12 along the center line of the second shaft 12, and the center line of the first shaft 11 and the center line of the second shaft 12 are aligned, whereby the first shaft 11 and the second shaft 12 constitute a double shaft structure. A needle bearing 13 is interposed between the first shaft 11 and the second shaft 12. Thereby, the first shaft 11 is rotatably held by the second shaft 12 via the needle bearing 13. The second shaft 12 is rotatably held by a housing 15 constituting a casing of the power transmission device 1 via a bearing 14.

The first shaft 11 is formed such that a portion having a constant length in the rotation axis direction from one end surface is smaller in diameter than a portion having a constant length. The small diameter portion is formed with a spline 16. The common member 21 is spline-coupled to the spline 16. The common member 21 integrally has: the first shaft 11 includes an annular portion 22 extending in a rotational radial direction thereof from the first shaft 11, a first cylindrical portion 23 extending from a distal end portion of the annular portion 22 to one side in a rotational axis direction of the first shaft 11, and a second cylindrical portion 24 extending from a distal end portion of the annular portion 22 to the other side in the rotational axis direction of the first shaft 11.

A plurality of annular plate-shaped clutch disks 25 are held on the outer peripheral surface of the first cylindrical portion 23 at intervals in the rotational axis direction of the first cylindrical portion 23. The housing 15 has a third cylindrical portion 26, and the third cylindrical portion 26 is formed in a cylindrical shape surrounding the outside of the first cylindrical portion 23 so as to be parallel to the first cylindrical portion 23. A plurality of annular plate-shaped clutch plates 27 are held on the inner peripheral surface of the third cylindrical portion 26 at intervals in the center line direction of the third cylindrical portion 26. The clutch disks 25 and the clutch plates 27 are arranged alternately in the center line direction. The clutch disc 25 is pressed against the clutch plate 27, whereby the rotation of the clutch disc 25 is prevented, and the pressing is released, whereby the rotation of the clutch disc 25 is allowed. That is, the clutch disc 25 and the clutch plate 27 constitute a parking brake 28 that is engaged and released to brake and release the first shaft 11.

A plurality of annular clutch plates 31 are held on the inner circumferential surface of the second cylindrical portion 24 at intervals in the rotational axis direction of the second cylindrical portion 24. The second cylindrical portion 24 faces the second shaft 12 from the radially outer side of the second shaft 12. A plurality of annular clutch disks 32 are held on the outer peripheral surface of the second shaft 12 at portions facing the second cylindrical portion 24 with intervals therebetween in the rotational axis direction of the second shaft 12. The clutch plates 31 and the clutch discs 32 are arranged alternately in the rotational axis direction. The first shaft 11 and the second shaft 12 are coupled to each other so as to rotate integrally by bringing the clutch plate 31 into pressure contact with the clutch disc 32, and the first shaft 11 and the second shaft 12 are separated from each other so as to rotate relatively by releasing the pressure contact. That is, the clutch plate 31 and the clutch disk 32 constitute a double shaft coupling clutch 33 that is engaged and released to engage and disengage the first shaft 11 and the second shaft 12.

Further, a spring 34 is interposed in a compressed state between the annular portion 22 of the common member 21 and a surface of the outer peripheral surface of the first shaft 11, which surface is caused by a difference in diameter.

A piston 35 is provided on the opposite side of the annular portion 22 of the common member 21 from the spring 34. The piston 35 is externally fitted to the first shaft 11 and is provided movably in the rotational axis direction of the first shaft 11. A cylinder 36 is provided on the opposite side of the annular portion 22 with respect to the piston 35. The cylinder 36 is externally fitted to the first shaft 11 and is fixed to the first shaft 11. An oil chamber 37 is formed between the piston 35 and the cylinder 36. An oil passage 38 is formed inside the first shaft 11. The oil passage 38 communicates with the oil chamber 37 via a connecting oil passage 39.

The parking brake 28 is provided with a pressing member 41 on the side opposite to the double shaft coupling clutch 33. The pressing member 41 has an annular acting portion 42 that presses the portion where the clutch disc 25 and the clutch plate 27 overlap. A plurality of springs 43 are interposed between the pressing member 41 and the housing 15, and the pressing member 41 is elastically biased toward the clutch plate 27 by the elastic force of the springs 43.

The pressing member 41 has a through hole 44 formed therein. The through hole 44 has cylindrical surfaces 45 and 46 centered on the rotation axis of the first shaft 11 in this order from the first shaft 11 side. The cylindrical surface 46 has a diameter smaller than that of the cylindrical surface 45, and an annular step surface 47 is provided between the cylindrical surface 45 and the cylindrical surface 46.

A moving member 51 is provided between the first shaft 11 and the pressing member 41. The moving member 51 integrally has: a first flat columnar portion 52 having an outer diameter corresponding to the cylindrical surface 45 of the pressing member 41; a second columnar portion 53 formed on the opposite side of the first columnar portion 52 from the first shaft 11 side and having an outer diameter corresponding to the cylindrical surface 46 of the pressing member 41; and a third cylindrical portion 54 formed on the opposite side of the second cylindrical portion 53 from the first shaft 11 side, and having a diameter smaller than that of the second cylindrical portion 53 and extending long.

The first columnar portion 52 is fitted to a portion surrounded by the cylindrical surface 45 of the pressing member 41. The second columnar portion 53 is inserted through a portion surrounded by the cylindrical surface 46 of the pressing member 41. The third cylindrical portion 54 is disengaged from the through hole 44 of the pressing member 41 and inserted into an insertion hole 55 formed through the housing 15. A screw 57 is formed at a portion of the third cylindrical portion 54 protruding to the outside of the housing 15, and a nut 58 is screwed to the portion where the screw 57 is formed.

An oil chamber 61 is formed between the pressing member 41 and the moving member 51. Further, the moving member 51 has an oil passage 62 formed along the center line thereof. The oil passage 62 is open at the distal end surface of the third cylindrical portion 54. The oil passage 62 communicates with the oil chamber 61 via a connecting oil passage 63.

< action >

In a state where the hydraulic oil does not flow into the oil passages 38, 62, as shown in fig. 1A, the pressing member 41 is biased toward the parking brake 28 by the elastic force of the spring 43, and the acting portion 42 of the pressing member 41 presses the clutch plate 27. Thereby, the clutch disc 25 is pressed against the clutch plate 27, the parking brake 28 is engaged, and the first shaft 11 is braked. The pressing force is transmitted to the double-shaft coupling clutch 33 via the common member 21, and the clutch plate 31 and the clutch disc 32 are pressed against each other. Thereby, the double shaft coupling clutch 33 is engaged, and the first shaft 11 and the second shaft 12 are coupled.

From this state, as shown in fig. 1B, when the hydraulic oil (pressure oil) is supplied to the oil passage 62 and supplied from the oil passage 62 to the oil chamber 61 via the connection oil passage 63, the pressing member 41 is moved in a direction away from the parking brake 28 against the elastic force of the spring 43 by the hydraulic pressure in the oil chamber 61. As a result, the parking brake 28 is released, and the brake of the first shaft 11 is released. Further, since the pressing force is not transmitted to the double shaft coupling clutch 33, the double shaft coupling clutch 33 is also released, and the coupling between the first shaft 11 and the second shaft 12 is released. As a result, the first shaft 11 and the second shaft 12 can rotate independently.

Thereafter, as shown in fig. 1C, the hydraulic oil is also supplied to the oil passage 38, and when the hydraulic oil is supplied from the oil passage 38 to the oil chamber 37 via the connecting oil passage 39, the piston 35 presses the common member 21 by the hydraulic pressure in the oil chamber 37. The clutch plate 31 and the clutch disk 32 of the biaxial coupling clutch 33 are pressed by the pressing force. Thereby, the double shaft coupling clutch 33 is engaged, and the first shaft 11 and the second shaft 12 are coupled.

The nut 58 is tightened during towing or adjustment of the combine. When the nut 58 is tightened, the moving member 51 moves to a side away from the parking brake 28. As shown in fig. 1D, during the movement of the moving member 51, the peripheral edge portion of the moving member 51 comes into contact with the pressing member 41, and the moving member 51 presses the pressing member 41. Thereby, the pressing member 41 moves in a direction away from the parking brake 28, the parking brake 28 is released, and the braking of the first shaft 11 is released. Further, since the pressing force is not transmitted to the double shaft coupling clutch 33, the double shaft coupling clutch 33 is also released, and the coupling between the first shaft 11 and the second shaft 12 is released. As a result, the first shaft 11 and the second shaft 12 can rotate independently.

< Effect >

As described above, the parking brake 28 and the double-shaft coupling clutch 33 can be released by supplying the hydraulic oil to the oil passage 62, and the parking brake 28 and the double-shaft coupling clutch 33 can be engaged by stopping the supply of the hydraulic oil. The parking brake 28 and the two-shaft coupling clutch 33 can be operated by one hydraulic operation structure. In addition, no lever is required for operation of the parking brake 28. Therefore, simplification of the structure of the power transmission device 1 can be achieved.

< modification example >

While the embodiments of the present invention have been described above, the present invention may be implemented in other embodiments, and various design changes may be made in the above-described configuration within the scope of the items described in the claims.

Second embodiment

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

< Power Transmission device >

Fig. 2A, 2B, and 2C are sectional views showing the configuration of the main part of the power transmission device 1 according to the embodiment of the present invention.

The power transmission device 1 is mounted on, for example, a combine harvester, and transmits power to the left and right traveling devices. The combine may be configured to include a 2-pump 2 motor of an HST (hydrostatic Transmission) corresponding to each of the left and right traveling devices, or may be configured to include an HST in common in the left and right traveling devices.

The power transmission device 1 includes a first gear 11. The first gear 11 always connects the running gear and the power transmission path. A shaft portion 12 is integrally formed with the first gear 11. The shaft portion 12 has a substantially cylindrical shape protruding from one end surface of the first gear 11 to one side, and has an axis common to the first gear 11. The inner race of the bearing 13 is fixed by being fitted to the shaft portion 12. The outer race of the bearing 13 is non-rotatably held by a housing 14 constituting a casing of the power transmission device 1. Thereby, the first gear 11 and the shaft portion 12 are rotatably held in the housing 14 via the bearing 13. A plurality of annular plate-shaped clutch disks 15 are held on the shaft portion 12 at intervals in the rotational axis direction of the shaft portion 12.

The housing 14 has a cylindrical portion 16 formed in a cylindrical shape concentric with the shaft portion 12. The cylindrical portion 16 surrounds the outer periphery of the shaft portion 12 and faces the shaft portion 12 in the rotational radial direction. A plurality of annular plate-shaped clutch plates 17 are held on the inner circumferential surface of the cylindrical portion 16 at intervals in the center line direction of the cylindrical portion 16. The clutch disks 15 and the clutch plates 17 are arranged alternately in the center line direction of the cylindrical portion 16. The clutch disk 15 is pressed against the clutch plate 17, whereby the rotation of the clutch disk 15 is prevented, and the pressing is released, whereby the rotation of the clutch disk 15 is allowed. That is, the clutch disc 15 and the clutch plate 17 constitute a parking brake 18 that is engaged and released to brake and release the first gear 11 and the shaft portion 12.

A pressing member 21 is provided on the clutch plate 17 side opposite to the bearing 13 side. The pressing member 21 has an annular operating portion 22 that presses a portion where the clutch disc 15 and the clutch plate 17 overlap. A plurality of springs 23 are interposed between the pressing member 21 and the housing 14, and the pressing member 21 is elastically biased toward the clutch plate 17 by the elastic force of the springs 23.

The pressing member 21 has a through hole 24 formed therein. The through hole 24 has cylindrical surfaces 25, 26, and 27 centered on the rotation axis of the first gear 11 in this order from the first gear 11 side. The diameter of the cylindrical surface 26 is smaller than that of the cylindrical surface 25, and the diameter of the cylindrical surface 27 is smaller than that of the cylindrical surface 26. Thus, the through hole 24 has an annular stepped surface 28 between the cylindrical surface 25 and the cylindrical surface 26.

A moving member 31 is provided between the first gear 11 and the pressing member 21. The moving member 31 integrally has: a first flat cylindrical portion 32 having an outer diameter corresponding to the cylindrical surface 25 of the pressing member 21; a second cylindrical portion 33 formed on the opposite side of the first cylindrical portion 32 from the first gear 11 side and having an outer diameter corresponding to the cylindrical surface 27 of the pressing member 21; and a third cylindrical portion 34 formed on the opposite side of the second cylindrical portion 33 from the first gear 11 side, and having a diameter smaller than that of the second cylindrical portion 33 and extending long.

The first columnar portion 32 is fitted to a portion surrounded by the cylindrical surface 25 of the pressing member 21. The second columnar portion 33 is inserted through a portion surrounded by the cylindrical surface 27 of the pressing member 21. The third cylindrical portion 34 is disengaged from the through hole 24 of the pressing member 21 and inserted into an insertion hole 35 formed through the housing 14. A screw 36 is formed in a portion of the third cylindrical portion 34 that protrudes outside the housing 14, and a nut 37 is screwed to the portion where the screw 36 is formed.

The first cylindrical portion 32 and the cylindrical surface 25 are sealed by a seal ring 41. Further, a seal ring 42 seals between the second cylindrical portion 33 and the cylindrical surface 27. Thereby, an oil chamber 43 is formed between the pressing member 21 and the moving member 31. Further, the moving member 31 has an oil passage 44 formed along the center line thereof. The oil passage 44 is open at the distal end surface of the third cylindrical portion 34. The oil passage 44 communicates with the oil chamber 43 via a connecting oil passage 45.

The second gear 51 is arranged with respect to the first gear 11 on the opposite side to the bearing 13, with a common axis of rotation with the first gear 11. Between the first gear 11 and the second gear 51, a first spline portion 52 and a second spline portion 53 are provided. The first spline portion 52 is annular around the rotation axis of the first gear 11, and has a spline on its outer circumferential surface. The second spline portion 53 is annular around the rotation axis of the second gear 51, and has a spline on its outer circumferential surface. The outer peripheral surface of the first spline portion 52 and the outer peripheral surface of the second spline portion 53 are formed to have the same diameter.

A shifter 54 is fitted to the outside of the first spline portion 52 and the second spline portion 53. A spline is formed on an inner peripheral surface of the shifter 54, and the shifter 54 is provided movably across the first spline portion 52 and the second spline portion 53 at a drive position spline-engaged with the first spline portion 52 and the second spline portion 53 and at a neutral position spline-engaged with only the first spline portion 52.

The shift fork 55 is connected to the shifter 54. The shift fork 55 is supported by a shaft 56 extending parallel to the rotational axis of the first gear 11. The shaft 56 is coupled to a coupling portion 57 extending in the radial direction from the first columnar portion 32 of the moving member 31, and is provided so as to be movable integrally with the moving member 31.

< Effect >

In a normal state, as shown in fig. 2A, the pressing member 21 is biased toward the parking brake 18 by the elastic force of the spring 23, and the operating portion 22 of the pressing member 21 presses the clutch plate 17. Thereby, the clutch disc 15 is pressed against the clutch plate 17, the parking brake 18 is engaged, and the first gear 11 is braked.

From this state, as shown by the hatching in fig. 2B, when the hydraulic oil (pressure oil) is supplied to the oil passage 44 and supplied to the oil chamber 43 through the connecting oil passage 45, the pressing member 21 is moved in the direction away from the parking brake 18 against the elastic force of the spring 23 by the hydraulic pressure in the oil chamber 43. As a result, the parking brake 18 is released, and the brake of the first gear 11 is released.

Therefore, an operation lever or the like for operating (engaging) the parking brake 18 is not required, and the parking brake 18 and the operation lever or the like do not need to be mechanically connected, so that the degree of freedom in layout of the components constituting the power transmission device 1 is improved.

At the time of towing or adjusting of the combine harvester, the nut 37 is tightened from the state shown in fig. 2A. When the nut 37 is tightened, the moving member 31 moves to a side away from the parking brake 18. In the middle of the movement of the moving member 31, as shown in fig. 2C, the first columnar portion 32 of the moving member 31 abuts against the step surface 28 of the pressing member 21, and the moving member 31 presses the pressing member 21. Thereby, the pressing member 21 moves in a direction away from the parking brake 18, the parking brake 18 is released, and the braking of the first gear 11 is released.

At this time, the shift fork 55 moves in conjunction with the movement of the moving member 31, the shifter 54 moves from the drive position to the neutral position, and the coupling between the first gear 11 and the second gear 51 is released. Therefore, an operation mechanism including an operation lever or the like is not required in the sub-transmission mechanism including the shifter 54, and hence the structure of the power transmission device 1 can be simplified. Further, since the position of the shift fork 55 is determined by the fastening amount of the nut 37, the shift fork 55 can be prevented from coming off the shifter 54.

< modification example >

While the embodiments of the present invention have been described above, the present invention may be implemented in other embodiments, and various design changes may be made in the above-described configuration within the scope of the items described in the claims.

Third embodiment

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

< combine harvester >

Fig. 3 is a right side view showing a front portion of the combine harvester 1 on which the transmission 32 according to the embodiment of the present invention is mounted.

The combine harvester 1 is a work vehicle that harvests grain and straw and threshes grain from the grain and straw while traveling in a field. The body 11 of the combine harvester 1 is supported by a pair of left and right traveling devices 12. In the travel device 12, in order to enable the combine harvester 1 to travel in a field, a crawler having an uneven ground passing capability is employed.

The machine body 11 is provided with a driving platform 13, a harvesting device 14, a threshing device 15 and a grain tank 16.

The cab 13 is disposed above the front end of the traveling device 12. The driver's seat 17 on which the operator sits is provided on the driver's seat 13, and an operation panel 18 operated by the operator is provided, for example, from the front to the left of the driver's seat 17. The operation panel 18 includes a main shift lever 21, a steering lever 22, and the like.

The main shift lever 21 is provided to be displaceable from a neutral position to a forward position on the front side and a reverse position on the rear side. When the main shift lever 21 is operated from the neutral position to the forward position, power in the forward direction is transmitted to the right and left traveling devices 12, and the machine body 11 moves forward. On the other hand, when the main shift lever 21 is operated from the neutral position to the reverse position, the power in the reverse direction is transmitted to the left and right traveling devices 12, and the machine body 11 is reversed. When the main shift lever 21 returns to the neutral position from the forward position or the reverse position, the machine body 11 stops. The forward or reverse speed can be changed according to the operation amount of the main shift lever 21.

The steering rod 22 is provided to be tiltable in the right and left direction and in the front and rear direction. The straight advance, the left turn, and the right turn of the machine body 11 can be switched by the left-right tilting operation of the steering lever 22. In addition, the harvesting unit 14 can be raised and lowered by the forward and backward tilting operation of the steering lever 22.

The harvesting device 14 is disposed in front of the traveling device 12. The harvesting device 14 includes a crop divider 23 at a front end thereof, and a harvesting knife 24 at a rear of the crop divider 23. The crop divider 23 and the harvesting knife 24 are supported by the harvesting unit frame 25. A harvesting cross frame 26 extending in the left-right direction is provided at the rear end of the harvesting device frame 25. One end of the harvesting main frame 27 is connected to the harvesting cross frame 26. The harvesting main frame 27 extends rearward from the harvesting cross frame 26, and the other end (disposed downward and forward, and the rear end) thereof is rotatably connected to the frame of the machine body 11. The harvesting main frame 27 can be swung by operating a cylinder (not shown) by tilting operation of the steering rod 22 in the forward and backward direction, and the crop divider 23 and the harvesting knife 24 are raised and lowered between a raised position where they are raised from the ground surface and a lowered position where they are lowered to the vicinity of the ground surface by the swinging movement. When the machine body 11 moves forward with the grain divider 23 and the harvesting knife 24 positioned at the lowered position, the grain stalks are harvested by the harvesting knife 24 while the roots of the grain stalks standing in the field are divided by the grain divider 23.

The threshing device 15 and the grain tank 16 are arranged side by side above the traveling device 12 and behind the harvesting device 14. The harvested straw is transported to the threshing device 15 by the harvesting device 14. The threshing device 15 conveys the root side of the grain stalks backward by a threshing supply chain, and supplies the ear tip side of the grain stalks to a threshing chamber for threshing. The grains are transported from the threshing device 15 to the grain tank 16, and the grains are accumulated in the grain tank 16. The grain discharging auger 28 is connected with the grain box 16, and grains accumulated in the grain box 16 can be discharged outside the machine by the grain discharging auger 28.

< Transmission device >

Fig. 4 is a view showing a partial structure of the transmission 32 of the combine harvester 1. Fig. 4 is a schematic diagram showing a structure from the engine 31 to the left HST33 and the right HST34, and a hydraulic circuit diagram showing a structure relating to the left HST33 and the right HST 34.

The combine harvester 1 is equipped with an engine 31 and a transmission 32 for transmitting power of the engine 31 to the traveling device 12 while changing the speed.

The Transmission 32 includes a left side HST (Hydro Static Transmission) 33 and a right side HST 34.

The left HST33 has a closed circuit structure in which the hydraulic pump 41 and the hydraulic motor 42 are connected by the first oil passage 43 and the second oil passage 44 so that the hydraulic oil circulates between the hydraulic pump 41 and the hydraulic motor 42. The first oil passage 43 is connected to a first port 45 of the hydraulic pump 41 and a first port 46 of the hydraulic motor 42. The second oil passage 44 is connected to a second port 47 of the hydraulic pump 41 and a second port 48 of the hydraulic motor 42.

Further, the left HST33 is provided with a supply pump 51. The feed pump 51 is a fixed displacement hydraulic pump, and discharges hydraulic oil to the feed oil passage 53 by rotation of the pump rotation shaft 52. The supply oil passage 53 is connected to the first oil passage 43 via a first check valve 54, and is connected to the second oil passage 44 via a second check valve 55. The supply oil passage 53 is connected to an oil tank 57 via a supply/release valve 56.

The hydraulic pressure of the supply oil passage 53 is maintained at a predetermined supply pressure by the function of the supply relief valve 56. When the hydraulic pressure of the first oil passage 43 is lower than the hydraulic pressure of the supply oil passage 53, that is, the supply pressure, the first check valve 54 opens, and the working oil is supplied from the supply oil passage 53 to the first oil passage 43 via the first check valve 54. When the hydraulic pressure in the second oil passage 44 is lower than the supply pressure, the second check valve 55 opens, and the hydraulic oil is supplied from the supply oil passage 53 to the second oil passage 44 via the second check valve 55. Thereby, the hydraulic pressures of the first oil passage 43 and the second oil passage 44 are maintained at the supply pressure or higher.

The left HST33 is configured as an integrated HST in which the hydraulic pump 41, the hydraulic motor 42, the first oil passage 43, the second oil passage 44, the first check valve 54, the second check valve 55, the supply/release valve 56, and the like are housed in a single housing.

The hydraulic pump 41 is a variable displacement swash plate type piston pump, and includes a cylinder block, a plurality of pistons radially arranged in the cylinder block, a pump swash plate on which the pistons slide, and the like. The hydraulic pump 41 and the feed pump 51 have a pump rotating shaft 52 in common, and the cylinder is provided so as to rotate integrally with the pump rotating shaft 52.

An electronically controlled servo piston 58 is provided to change the inclination angle of the swash plate of the hydraulic pump 41. The servo piston 58 has: a first pressure chamber 62 to which hydraulic pressure is supplied from the forward side pressure control valve 61, and a second pressure chamber 64 to which hydraulic pressure is supplied from the reverse side pressure control valve 63. The servo piston 58 has a rod 65 that moves linearly by a differential pressure between the first pressure chamber 62 and the second pressure chamber 64, and the tilt angle of the swash plate of the pump is changed by the linear movement of the rod 65.

The discharge amount of the hydraulic oil from the hydraulic pump 41 decreases as the inclination angle of the pump swash plate with respect to the axis of the pump rotary shaft 52 of the hydraulic pump 41 (the rotation axis of the cylinder block) increases, and when the inclination angle of the pump swash plate is 90 °, the discharge of the hydraulic oil from the hydraulic pump 41 is stopped. When the inclination angle of the pump swash plate exceeds 90 ° (when the inclination is reversed), the discharge direction of the hydraulic oil from the hydraulic pump 41 is reversed when the inclination angle is less than 90 °.

The hydraulic motor 42 is a variable displacement swash plate type piston motor, and includes a motor rotary shaft 71, a cylinder block 72 (see fig. 5) that rotates integrally with the motor rotary shaft 71, a plurality of pistons 73 (see fig. 5) disposed radially within the cylinder block 72, a motor swash plate 74 (see fig. 5) that presses the pistons 73, and the like. When the inclination angle of the motor swash plate 74 with respect to the axis of the motor rotary shaft 71 of the hydraulic motor 42 (the rotation axis of the cylinder block 72) is constant, the rotation speed of the motor rotary shaft 71 increases as the amount of hydraulic oil supplied to the hydraulic motor 42, that is, the amount of hydraulic oil discharged from the hydraulic pump 41 increases.

When the amount of hydraulic oil supplied to the hydraulic motor 42 is constant, the rotation speed of the motor rotary shaft 71 decreases as the inclination angle of the motor swash plate 74 increases. A sub-transmission piston 75 is provided for changing the inclination angle of the motor swash plate 74 of the hydraulic motor 42. The low-speed switching valve 76 and the high-speed switching valve 77 are connected to the sub-transmission piston 75. When the low-speed switching valve 76 is turned on and the high-speed switching valve 77 is turned off, and hydraulic pressure is supplied from the low-speed switching valve 76 to the sub-transmission piston 75, the rod 78 of the sub-transmission piston 75 is positioned at the low-speed position, and the inclination angle of the motor swash plate 74 is relatively increased. On the other hand, the low-speed switching valve 76 is closed, the high-speed switching valve 77 is opened, and hydraulic pressure is supplied from the high-speed switching valve 77 to the sub-transmission piston 75, so that the rod 78 of the sub-transmission piston 75 is positioned at the high-speed position, and the inclination angle of the motor swash plate 74 is relatively decreased. Therefore, by switching on or off the low speed switching valve 76 and the high speed switching valve 77, it is possible to switch to two stages, i.e., a high speed stage in which the rotation speed of the motor rotary shaft 71 is relatively increased and a low speed stage in which the rotation speed of the motor rotary shaft 71 is relatively decreased.

Since the right HST34 has the same structure as the left HST33, the parts corresponding to the parts of the left HST33 in the right HST34 are denoted by the same reference numerals as the parts described above, and the description thereof is omitted.

The power of the engine 31 is input to the pump rotation shafts 52 of the left HST33 and the right HST 34. Specifically, a pulley 82 is provided on the output shaft 81 of the engine 31 so as not to be relatively rotatable. The transmission 32 includes an input shaft 83 extending parallel to the output shaft 81 of the engine 31. A pulley 84 is provided on the input shaft 83 so as not to be rotatable relative thereto. An endless belt 85 is wound between the pulleys 82, 84. Further, an input gear 86 is provided on the input shaft 83 so as not to be relatively rotatable. The intermediate gear 87 meshes with the input gear 86, and the pump gear 88 provided on the pump rotating shaft 52 of the right HST34 so as not to be relatively rotatable meshes with the intermediate gear 87. The pump gear 88 is engaged with a pump gear 89 provided on the pump rotating shaft 52 of the left HST33 so as not to be relatively rotatable.

Thereby, the power of the engine 31 is transmitted from the output shaft 81 to the pulley 84 via the pulley 82 and the belt 85, and rotates the input shaft 83 integrally with the pulley 84. The power (rotation) of the input shaft 83 is transmitted from the input gear 86 to the pump gear 88 of the right HST34 via the intermediate gear 87, and the pump rotation shaft 52 of the right HST34 is rotated in a predetermined direction integrally with the pump gear 88. The power of the input shaft 83 is transmitted from the input gear 86 to the pump gear 88 of the right HST34 via the intermediate gear 87, and further transmitted from the pump gear 88 to the pump gear 89, and the pump rotary shaft 52 of the left HST33 is rotated in the direction opposite to the predetermined direction integrally with the pump gear 89. Therefore, when the inclination angles of the pump swash plates of the hydraulic pumps 41 of the left HST33 and the right HST34 are the same, the motor rotary shaft 71 of the hydraulic motor 42 of the left HST33 and the motor rotary shaft 71 of the hydraulic motor 42 of the right HST34 rotate in opposite directions to each other.

Fig. 5 is a cross-sectional view showing a part of the transmission 32, and shows a configuration from the hydraulic motor 42 of the left HST33 and the right HST34 to a point halfway through the travel device 12.

The hydraulic motors 42 of the left HST33 and the right HST34 are arranged in bilateral symmetry with each other such that the motor rotation shafts 71 are aligned on the same axis (have a common axis) and the axes thereof are parallel to the axes of the left and right axles.

In the following description, the motor rotation shaft 71 of the left HST33 is referred to as "motor rotation shaft 71L", and the motor rotation shaft 71 of the right HST34 is referred to as "motor rotation shaft 71R".

The laterally outer end portions of the motor rotary shafts 71L, 71R are rotatably supported by a unit case 101 constituting a housing of the transmission 32 via bearings 102L, 102R, respectively. The motor output gears 103L and 103R are supported by the left and right inner ends of the motor rotary shafts 71L and 71R, respectively, so as to be relatively non-rotatable.

First and second intermediate shafts 104 and 105 are provided between the motor rotary shafts 71L and 71R and the axle. The respective axes of the first intermediate shaft 104 and the second intermediate shaft 105 are parallel to the axes of the motor rotary shafts 71L, 71R. The first intermediate shaft 104 is non-rotatably supported by the unit case 101. The left end portion of the second intermediate shaft 105 is rotatably supported by the unit case 101 via a bearing 106. A cylindrical sleeve 107 is fitted over the right portion 105R of the second intermediate shaft 105. The inner race of the bearing 108 is fitted to the sleeve 107 so as not to rotate relatively. The outer race of the bearing 108 is fixed to the unit case 101. Thereby, the second intermediate shaft 105 is rotatably held by the unit case 101.

The first left intermediate gear 111L and the first right intermediate gear 111R are aligned in the left-right direction and rotatably held by the first intermediate shaft 104. The left motor output gear 103L meshes with the first left intermediate gear 111L, and the right motor output gear 103R meshes with the first right intermediate gear 111R. The second left and right intermediate gears 112L and 112R are fixedly held in the left and right portions 105L and 105R of the second intermediate shaft 105, respectively, in a left-right arrangement. The first left intermediate gear 111L meshes with the second left intermediate gear 112L, and the first right intermediate gear 111R meshes with the second right intermediate gear 112R.

An annular groove 113L centered on the axis of the second intermediate shaft 105 is formed in the left side surface of the second left intermediate gear 112L. A plurality of internal teeth 114L protruding toward the rotation center side are formed in a circumferential direction at the left end portion of the groove portion 113L. A left shift gear 115L is provided on the left side of the second left intermediate gear 112L. The left shift gear 115L is held in the left portion 105L of the second intermediate shaft 105 so as to be relatively non-rotatable and movable in the axial direction of the second intermediate shaft 105. The left shift gear 115L has a plurality of external teeth 116L on the outer peripheral surface. A notch 117 notched over the entire circumference is formed in the right side portion of the outer tooth 116L.

An annular groove portion 113R centered on the axis of the second intermediate shaft 105 is formed on the right side surface of the second right intermediate gear 112R. A plurality of internal teeth 114R protruding toward the rotation center side are formed in a circumferential direction at the right end of the groove portion 113R. A right shift gear 115R is provided on the right side of the second right intermediate gear 112R. The right shift gear 115R is held by the sleeve 107 so as to be relatively non-rotatable and movable in the axial direction of the second intermediate shaft 105. The right shift gear 115R has a plurality of external teeth 116R on an outer peripheral surface.

< neutral Transmission mechanism >

Fig. 6A, 6B, 6C, and 6D are cross-sectional views showing the structure of the neutral shift mechanism 120.

The transmission 32 is provided with a neutral shift mechanism 120 for generating a neutral state. Neutral transmission 120 includes a shift element including a shift rail 121, a left shift fork 122L, and a right shift fork 122R.

The shift rail 121 is provided at a position apart from the second intermediate shaft 105 in a direction orthogonal to the axial direction thereof. A center line of shift rail 121 extends parallel to the axis of second intermediate shaft 105, and shift rail 121 is held on unit case 101 so as to be movable in the center line direction.

Left shift fork 122L is fixed to shift rail 121, and extends from shift rail 121 toward left shift gear 115L in a direction orthogonal to the center line of shift rail 121. A recess 123L is formed on the outer peripheral surface of the left shift gear 115L over the entire periphery. The front end portion of the left shift fork 122L is fitted into the recess 123L of the left shift gear 115L with a gap that allows the left shift gear 115L to rotate.

Right shift fork 122R is fixed to shift rail 121, and extends from shift rail 121 toward right shift gear 115R in a direction orthogonal to the center line of shift rail 121. A recess 123R is formed on the outer peripheral surface of the right shift gear 115R over the entire periphery. The front end portion of the right shift fork 122R is fitted into the recess 123R of the right shift gear 115R with a gap that allows the right shift gear 115R to rotate.

An operation groove 124 extending in the circumferential direction is formed at the left end portion of the shift rail 121. The front end of a cylindrical operating projection 126 extending from the front end of shift operating piece 125 toward shift rail 121 enters operating groove 124 from the radial direction of shift rail 121. A support shaft 127 that is orthogonal to both the center line direction of shift rail 121 and the direction in which shift operating piece 125 extends is fixedly provided at the base end of shift operating piece 125. The support shaft 127 is rotatably supported by the unit case 101. An operating arm 128 extending in a direction orthogonal to both the axis of the support shaft 127 and the direction in which the shift operating piece 125 extends is supported by the support shaft 127 so as not to be rotatable relative thereto. The length from the center of the support shaft 127 to the tip of the operation arm 128 is larger than the length from the center of the support shaft 127 to the center of the operation protrusion 126.

A coil-shaped spring 129 fitted around the shift fork shaft 121 is interposed in a compressed state between the unit case 101 and the right shift fork 122R. Thereby, the elastic force of the spring 129 is applied to the right shift fork 122R, and the shift fork shaft 121 is biased leftward by the elastic force.

In a state where the operating arm 128 is not operated, as shown in fig. 6A, the shift rail 121 is located at the left end of the movable range, the external teeth 116L of the left shift gear 115L mesh with the internal teeth 114L of the second left intermediate gear 112L, and the external teeth 116R of the right shift gear 115R mesh with the internal teeth 114R of the second right intermediate gear 112R.

Therefore, the power (rotation) transmitted from the motor rotating shaft 71L to the second left intermediate gear 112L via the first left intermediate gear 111L is transmitted from the second left intermediate gear 112L to the left shift gear 115L, and is transmitted from the left shift gear 115L to the left axle via a gear train (not shown), whereby the left travel device 12 is driven. The left power transmission mechanism is configured by a gear train that transmits power from the first left intermediate gear 111L, the second left intermediate gear 112L, the left shift gear 115L, and the left shift gear 115L to the left axle.

The power (rotation) transmitted from the motor rotating shaft 71R to the second right intermediate gear 112R via the first right intermediate gear 111R is transmitted from the second right intermediate gear 112R to the right shift gear 115R, and transmitted from the right shift gear 115R to the right axle via a gear train (not shown), whereby the right running gear 12 is driven. The right power transmission mechanism is configured by a gear train that transmits power from the first right intermediate gear 111R, the second right intermediate gear 112R, the right shift gear 115R, and the right shift gear 115R to the right axle.

When the operating arm 128 is operated to raise the tip, the shift operating piece 125 is pivoted about the support shaft 127 as a fulcrum in accordance with the pivoting of the operating arm 128, and the shift rail 121 moves in the right direction. In a state where the shift rail 121 is positioned at the right end of the movable range, as shown in fig. 6B, the external teeth 116L of the left shift gear 115L and the internal teeth 114L of the second left intermediate gear 112L are disengaged, and the external teeth 116R of the right shift gear 115R and the internal teeth 114R of the second right intermediate gear 112R are disengaged. Therefore, the power (rotation) transmitted from the motor rotating shaft 71 to the second left intermediate gear 112L via the first left intermediate gear 111L is not transmitted from the second left intermediate gear 112L to the left shift gear 115L and the right shift gear 115R. That is, the transmission 32 is in a neutral state in which power from the engine 31 (the left HST33 and the right HST34) is not transmitted to the left and right axles.

An arc-shaped locking recess 131 that is recessed upward is formed at the distal end of the operating arm 128. The neutral state of the transmission 32 can be maintained by engaging the engaging recess 131 with the engaging projection 132 fixedly provided on the unit case 101.

When the locking concave portion 131 is disengaged from the locking convex portion 132 and the force for lifting the distal end of the operating arm 128 is released, the shift rail 121 is moved leftward by the biasing force (elastic force) of the spring 129. When the external teeth 116R of the right shift gear 115R and the internal teeth 114R of the second right intermediate gear 112R are opposite in tooth space, the external teeth 116R of the right shift gear 115R enter the tooth space of the second right intermediate gear 112R by the movement of the shift rail 121, and the second right intermediate gear 112R meshes with the right shift gear 115R. On the other hand, when the external teeth 116R of the right shift gear 115R do not face the tooth grooves of the second right intermediate gear 112R, the external teeth 116R of the right shift gear 115R abut the internal teeth 114R of the second right intermediate gear 112R and the right shift gear 115R and the second right intermediate gear 112R do not mesh with each other due to the shift fork 121 moving as shown in fig. 6C. At this time, a gap is generated between a portion on the right side of the notched portion 117 of the external teeth 116L of the left shift gear 115L (hereinafter simply referred to as "external teeth 116L") and the internal teeth 114L of the second left intermediate gear 112L.

Since the shift rail 121 is biased in the left direction by the spring 129, the second right intermediate gear 112R starts rotating from a state where the external teeth 116R of the right shift gear 115R and the internal teeth 114R of the second right intermediate gear 112R are in contact, and when the external teeth 116R of the right shift gear 115R and the tooth grooves of the second right intermediate gear 112R face each other, the shift rail 121 further moves in the left direction as shown in fig. 6D, and the external teeth 116R of the right shift gear 115R enter the tooth grooves of the second right intermediate gear 112R.

Thereafter, the shift rail 121 is further moved leftward, and when the external teeth 116L of the left shift gear 115L and the internal teeth 114L of the second left intermediate gear 112L face each other, the external teeth 116L of the left shift gear 115L enter the teeth grooves of the second left intermediate gear 112L, and the second left intermediate gear 112L meshes with the left shift gear 115L. On the other hand, when the external teeth 116L of the left shift gear 115L do not face the tooth grooves of the second left intermediate gear 112L, the external teeth 116L of the left shift gear 115L abut the internal teeth 114L of the second left intermediate gear 112L by the movement of the shift rail 121, and the left shift gear 115L and the second left intermediate gear 112L do not mesh with each other.

Since the shift rail 121 is biased in the left direction by the spring 129, the second left intermediate gear 112L starts rotating from a state where the external teeth 116L of the left shift gear 115L and the internal teeth 114L of the second left intermediate gear 112L are in contact, and when the external teeth 116L of the left shift gear 115L and the tooth grooves of the second left intermediate gear 112L face each other, the shift rail 121 further moves in the left direction, and the external teeth 116L of the left shift gear 115L enter the tooth grooves of the second left intermediate gear 112L.

According to the above, the engagement of the second left intermediate gear 112L with the left shift gear 115L and the engagement of the second right intermediate gear 112R with the right shift gear 115R are achieved.

< Effect >

As described above, by the neutral transmission mechanism 120, the engagement/disengagement of the second left intermediate gear 112L with the left shift gear 115L and the engagement/disengagement of the second right intermediate gear 112R with the right shift gear 115R can be switched, and the gear engagement can be favorably realized.

In order to move shift rail 121, a front end portion of an operation projection 126 extending from a front end portion of shift operation piece 125 enters an operation groove 124 formed in shift rail 121, and an operation arm 128 that rotates integrally with shift operation piece 125 is supported on a support shaft 127 that supports shift operation piece 125. Further, the length from the center of the support shaft 127 to the front end of the operation arm 128 is larger than the length from the center of the support shaft 127 to the center of the operation protrusion 126. Thus, the lever principle works, and the shift rail 121 can be moved well against the urging force of the spring 129 even if the force applied to the operating arm 128 is small.

In addition, a spring 129 is interposed between the unit case 101 and the right shift fork 122R. Thus, a separate portion for coupling one end of spring 129 to shift fork shaft 121 is not required, and shift fork shaft 121 can be simply configured.

< modification example >

While one embodiment of the present invention has been described above, the present invention may be implemented in other embodiments.

For example, in the above-described embodiment, the shift rail 121 is moved by the turning operation of the operating arm 128, but the operating member operated to move the shift rail 121 may be configured to move the shift rail 121 by a linear operation along the center line of the shift rail 121.

Further, although the combine harvester 1 is proposed as an example of the work vehicle, the present invention is not limited to the combine harvester 1, and may be applied to a work vehicle other than the combine harvester 1, such as a harvester that harvests vegetables such as carrots, radishes, green beans, and cabbage.

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

Fourth embodiment

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

< fixing Structure of axle Box >

Fig. 7 is a cross-sectional view showing a structure in the vicinity of the right axle 6 of the combine harvester 1 according to the embodiment of the present invention.

The combine harvester 1 includes a power transmission mechanism 3 for transmitting power of an engine (not shown) to the traveling device 2. The traveling device 2 is, for example, a crawler belt having a capability of passing through rough terrain, and includes a sprocket 4. The power Transmission mechanism 3 includes an HST (Hydro Static Transmission), a Transmission 5, and left and right axles 6. The power of the engine is shifted by the HST and transmitted from the HST to the left and right axles 6 via the transmission 5. The left and right axles 6 are coupled to the left and right sprockets 4, respectively, so as not to be relatively rotatable. Thus, when the power of the engine is transmitted to the axle 6, the sprocket 4 rotates integrally with the axle 6.

The transmission 5 is housed in the main body case 11. The main body case 11 is integrally formed with: a wall portion 12 extending in a direction orthogonal to the vehicle width direction of the combine harvester 1, and a cylindrical insertion portion 13 extending outward in the vehicle width direction from the wall portion 12. On the inner peripheral surface of the insertion portion 13, two gasket grooves 14, 15 are formed over the entire circumference in the circumferential direction with a gap therebetween in the vehicle width direction. Annular gaskets 16 and 17 are fitted in the gasket grooves 14 and 15, respectively.

The axle 6 is inserted through the axle box 21. The axle box 21 is a metal casting, and integrally includes a cylindrical portion 22 and a plurality of fixing portions 23 extending from the cylindrical portion 22 to the periphery.

The end of the cylindrical portion 22 on the main body case 11 side is inserted into the insertion portion 13 of the main body case 11. In the insertion portion 13, the gaskets 16 and 17 are in contact with the outer peripheral surface of the cylindrical portion 22, and thereby the inner peripheral surface of the insertion portion 13 and the outer peripheral surface of the cylindrical portion 22 are liquid-tightly sealed. Further, a bolt 24 is inserted into the insertion portion 13 of the main body case 11 at a position outside the washers 16 and 17 in the vehicle width direction, and the tip of the bolt 24 enters a groove 25 formed in the outer peripheral surface of the cylindrical portion 22. The bolt 24 is used as a retaining member when the axle box 21 is assembled to the body case 11. Therefore, the cylindrical portion 22 is not fixed to the insertion portion 13 by the bolt 24.

Bearings 26 and 27 are fitted into both end portions of the cylindrical portion 22 in the axial direction. The axle 6 is inserted into the cylindrical portion 22 and is held by the bearings 26 and 27 so as to be rotatable relative to the cylindrical portion 22. The axle 6 enters the main body case 11 and is coupled to a gear 28 included in the power transmission mechanism 3 so as to be relatively non-rotatable in the main body case 11.

The fixing portions 23 are provided with, for example, four. The two fixing portions 23 are arranged in the vehicle width direction and formed in a substantially semicircular plate shape protruding upward from the upper end of the outer peripheral surface of the cylindrical portion 22. The remaining two fixing portions 23 are arranged in the vehicle width direction and formed in a substantially semicircular plate shape protruding downward from the lower end of the outer peripheral surface of the cylindrical portion 22.

The axle box 21 is fixed to a frame 31 of the combine harvester 1 by screwing bolts 29 inserted through the fixing portions 23 into the frame 31.

Fig. 7 shows the right axle 6, but the left axle 6 is configured such that the right axle 6 is turned upside down, for example.

< Effect >

As described above, since the axle box 21 is fixed to the frame 31 of the combine harvester 1, even when a large lateral tensile load is applied to the sprocket 4 coupled to the axle 6, damage to the main body case 11 and the like housing the power transmission mechanism 3 that transmits power to the axle 6 can be suppressed.

In the axle box 21, the structure of the axle box 21 is simpler and the strength can be improved as compared with the axle box 55 having the structure of the conventional axle box 55 shown in fig. 8, that is, the structure in which the housing body 56 and the flange portion 57 are fixed to each other by welding. In addition, in the structure of the axle box 21, welding is not required, and therefore, the processing cost can be reduced.

< modification example >

While the embodiments of the present invention have been described above, the present invention can be implemented in other embodiments.

For example, although the combine harvester 1 is proposed as an example of a work vehicle, the present invention is not limited to the combine harvester 1, and may be applied to a work vehicle other than the combine harvester 1, such as a harvester that harvests vegetables such as carrots, radishes, green beans, and cabbage.

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