WO2018173389A1

WO2018173389A1 - Work vehicle

Info

Publication number: WO2018173389A1
Application number: PCT/JP2017/045108
Authority: WO
Inventors: 正円茂夫
Original assignee: 株式会社クボタ
Priority date: 2017-03-24
Filing date: 2017-12-15
Publication date: 2018-09-27
Also published as: JP6824089B2; JP2018161939A; PH12018501102A1

Abstract

A work vehicle, wherein a handle shaft 35 and a boss member 39 are fitted together and a first key member 40 is engaged with both a first engagement recess 51 of the handle shaft 35 and a first through-hole 45 of the boss member 39, thereby restricting relative movement between the boss member 39 and the handle shaft 35 around the X rotation axis. Furthermore, a steering shaft 34 and the boss member 39 are fitted together and a second key member 41 is engaged with both a second engagement recess 58 of the steering shaft 34 and a second through-hole 46 of the boss member 39, thereby restricting relative movement between the boss member 39 and the steering shaft 34 around the X rotation axis.

Description

Work vehicle

The present invention relates to a work vehicle including a handle shaft coupled to a steering handle and a steering shaft that is disposed on the same rotation axis as the handle shaft and operates a steering mechanism.

A conventional work vehicle is described in Patent Document 1, for example. The work vehicle of this document is fitted into the handle shaft and the steering shaft (“input shaft” in the same document) with a different shape so that the handle shaft and the steering shaft rotate integrally around the rotation axis. There is provided a connecting mechanism for connecting to.

Japanese Unexamined Patent Publication No. 2014-129061 (JP2014-129061A)

However, in the above-described conventional technology, the handle shaft and the steering shaft have a structure that can move relative to each other along the rotational axis in the coupling mechanism. When applied repeatedly, the deformed fitting portion of the handle shaft and the deformed fitting portion of the steering shaft are worn by sliding, and there is a possibility that rattling occurs between the handle shaft and the steering shaft.

In view of the above circumstances, an object of the present invention is to provide a work vehicle in which rattling is unlikely to occur between a handle shaft and a steering shaft.

The work vehicle of the present invention is
A handle shaft coupled to the steering handle;
A steering shaft disposed on the same rotation axis as the handle shaft and operating a steering mechanism;
A coupling mechanism that is deformed and fitted to the handle shaft and the steering shaft and connects the handle shaft and the steering shaft so as to rotate integrally around the rotation axis;
A tubular boss member provided in the coupling mechanism across the handle shaft and the steering shaft, and through which a shaft end portion of the handle shaft and a shaft end portion of the steering shaft are inserted, and the boss member And a first key member attached in a state extending over the handle shaft, and a second key member attached in a state extending over the boss member and the steering shaft,
A first engagement recess is formed in an outer peripheral portion of the deformed fitting portion with the coupling mechanism in the handle shaft, and extends inside and outside the boss member to a location corresponding to the first engagement recess in the boss member. A first through hole is formed, and the first engagement recess communicates with the first through hole, whereby an insertion hole corresponding to the outer peripheral shape of the first key member is configured,
The first key member is inserted into the first engagement recess and the first through hole, and engages with both the first engagement recess and the first through hole, so that the rotation axis direction Restricting relative movement between the boss member and the handle shaft in
A second engagement recess is formed in the outer peripheral portion of the deformed fitting portion with the coupling mechanism in the steering shaft, and extends to the inside and outside of the boss member at a position corresponding to the second engagement recess in the boss member. A second through hole is formed, and the second engagement recess and the second through hole communicate with each other, thereby forming an insertion hole corresponding to the outer peripheral shape of the second key member,
The second key member is inserted into the second engagement recess and the second through hole, and engages with both the second engagement recess and the second through hole to rotate in the rotational axis direction. The relative movement between the boss member and the steering shaft is restricted.

According to the present invention, the handle shaft and the steering shaft are integrally rotated around the rotation axis by fitting the coupling mechanism to the handle shaft and the steering shaft.
Then, the first key member is inserted through the insertion hole formed in the outer peripheral portion of the deformed fitting portion in the handle shaft, so that the boss member and the handle shaft are restricted from moving in the rotational axis direction. Since the second key member is inserted into the insertion hole formed in the outer peripheral portion of the deformed fitting portion in the steering shaft, the movement of the handle shaft and the steering shaft in the direction of the rotational axis is restricted.
As a result, the handle shaft and the steering shaft do not move relative to each other around the rotation axis and are difficult to move relative to the rotation axis due to the coupling via the coupling mechanism. For this reason, even when a load such as vibration due to ground work is repeatedly applied, wear of the irregularly shaped fitting portion on the handle shaft and the irregularly shaped fitting portion on the steering shaft is less likely to occur.
Therefore, according to the present invention, rattling is unlikely to occur between the handle shaft and the steering shaft.

In the present invention,
Preferably, the first engagement recess is a circumferential groove extending over the entire outer periphery of the handle shaft, and the second engagement recess is a circumferential groove extending over the entire outer periphery of the steering shaft. is there.

According to the above configuration, for example, when the odd-shaped fitting portion is a spline mechanism, when the handle shaft is assembled to the steering shaft, the first key member is attached to the handle regardless of the phase relationship between the steering shaft and the handle shaft. The first engagement recess that is a circumferential groove in the shaft can be inserted, and the second key member can be inserted into the second engagement recess that is a circumferential groove in the steering shaft. For this reason, it becomes easy to assemble the handle shaft with respect to the steering shaft.

In the present invention,
The boss member is configured in a C-shaped cross section having a cut in the circumferential direction,
It is preferable that the first key member and the second key member are fasteners that are inserted from one side to the other side of the cut and fastened and fixed.

According to the above configuration, by tightening the first key member and the second key member, the cut is narrowed and the boss member is reduced in diameter, and the inner surface of the boss member presses the outer surface of the handle shaft and the outer surface of the steering shaft. Works. By this pressing force, the relative movement of the boss member and the handle shaft around the rotation axis and the rotation axis, and the relative movement of the boss member and the handle shaft around the rotation axis and the rotation axis. Can be firmly regulated.

In the present invention,
The first engaging recess and the first through hole are pierced through the outer periphery of the odd-shaped fitting portion of the handle shaft as a result of the communication between the first engaging recess and the first through hole. Is configured to form,
The second engagement recess and the second through hole are pierced through the outer periphery of the deformed fitting portion of the steering shaft by the second engagement recess and the second through hole communicating with each other. It is preferable that the structure is formed.

According to the above configuration, for example, the insertion hole formed by the first engagement recess and the first through hole extends in a normal line, or the insertion hole formed by the second engagement recess and the second through hole is legal. Compared to the linearly extending mode, it is possible to reduce the loss of the steering shaft due to the first engagement recess and the loss of the steering shaft due to the second engagement recess. For this reason, the fall of the rigidity in a coupling mechanism will be suppressed.

It is the whole tractor side view. It is a figure which shows the outline of the cross-sectional structure in a steering wheel post, and a steering operation system. It is sectional drawing which shows the axial direction cross section of the periphery of a coupling mechanism. It is sectional drawing which shows the radial direction cross section of a handle shaft and the periphery of a boss | hub member. It is sectional drawing which shows the radial direction cross section of a steering shaft and the periphery of a boss | hub member. It is an exploded view explaining how to assemble a handle shaft, a steering shaft, a boss member, a first key member, and a second key member. It is sectional drawing which shows the radial direction cross section of the periphery of a handle shaft and a boss member in another embodiment (1). It is sectional drawing which shows the radial direction cross section of the periphery of a steering shaft and a boss | hub member in another embodiment (2).

As shown in FIG. 1, a traveling machine body of a tractor (an example of a “work vehicle”) is configured to be able to travel by a traveling device including a pair of left and right front wheels 11 and a pair of left and right rear wheels 12. The left and right front wheels 11 are arranged at the front part of the body frame extending along the front-rear direction, and can be driven and steered. The left and right rear wheels 12 are disposed at the rear part of the body frame and can be driven. That is, this tractor is configured as a four-wheel drive type. At the rear part of the traveling machine body, a connecting device 13 for connecting a working device (not shown) for performing ground work is provided. The arrow F in FIG. 1 is “front” that is the forward direction of the traveling machine body, and the arrow B in FIG. 1 is “rear” that is the backward direction of the traveling machine body.

A driving unit 14 is provided at a location from the front and rear central portion to the rear portion of the traveling machine body for the driver to perform a driving operation. The driver 14 includes a driver seat 15 on which a driver can be seated, a wheel-type steering handle 16 that steers the front wheels 11, a fall frame 17 for preventing overturning, and the like.

The traveling machine body includes a mounting frame 19 to which the engine 18 can be attached, a clutch housing 20 integrally connected to the rear side of the engine 18, a transmission case 21 on the rear side, and a transmission case 22 that connects the clutch housing 20 and the transmission case 21. Etc. are provided. The engine 18 is covered with an openable / closable bonnet 18A. Based on the power of the engine 18, the left and right front wheels 11 and rear wheels 12, and a work device (not shown) can be driven.

[Steering operation of front wheels]
As shown in FIGS. 1 and 2, the traveling machine body includes a knuckle arm 23 for steering the left and right front wheels 11, and a tie rod 24 is connected across the left and right knuckle arms 23. A steering rod 25 is linked to one of the left and right knuckle arms 23. The steering rod 25 is linked to an operation arm 26 to which the operation of the steering handle 16 is transmitted.

As shown in FIG. 2 and the like, a box-shaped support base 27 is supported on the body frame. A steering mechanism 28 is built in the support base 27. A handle post 29 extending obliquely rearward and upward is supported on the upper portion of the support base 27. The handle post 29 includes a bracket 30 connected to the support base 27, a gate-shaped support frame 31 supported on the upper portion of the bracket 30, and a hollow hollow frame supported on the upper portion of the support frame 31. 32. The hollow frame 32 is connected and supported to a standing frame 33A at the rear of the bonnet 18A via a plate-like support member 33 standing from the body frame. The upper end of the hollow frame 32 is open.

As shown in FIGS. 2 and 3, the steering shaft 34 for steering operation protrudes upward from the upper part of the support base 27 and extends so as to enter the inside of the handle post 29 (the space in the support frame 31). ing. The steering shaft 34 for operating the steering mechanism 28 is disposed on the same rotation axis X as the handle shaft 35 that connects and fixes the steering handle 16.

As shown in FIGS. 2 to 5, the connecting portion between the handle shaft 35 and the steering shaft 34 is deformed and fitted to the handle shaft 35 and the steering shaft 34 so that the handle shaft 35 and the steering shaft 34 are connected to each other. A coupling mechanism 36 that is coupled so as to rotate integrally around the rotation axis X is provided.

[Coupling mechanism]
As shown in FIGS. 2 to 5, the coupling mechanism 36 is provided across the handle shaft 35 and the steering shaft 34, and includes a shaft end portion 37 of the handle shaft 35 and a shaft end portion 38 of the steering shaft 34. A cylindrical boss member 39 to be inserted, a first key member 40 attached in a state extending over the boss member 39 and the handle shaft 35, and a second key member attached in a state extending over the boss member 39 and the steering shaft 34 41.

As shown in FIGS. 3 and 6, the boss member 39 is a cylindrical member that is long in the direction of the rotational axis X. A first female spline portion 42 corresponding to the handle shaft 35 and a second female spline portion 43 corresponding to the steering shaft 34 are provided on the inner peripheral portion of the boss member 39. The first female spline part 42 and the second female spline part 43 are a continuous female spline part. The boss member 39 has a C-shaped cross section having a cut 44 in the circumferential direction. The boss member 39 is made of a material different from that of the handle shaft 35 and the steering shaft 34. For example, the boss member 39 is made of ductile cast iron (FCD). The flange portion of the boss member 39 is provided with a pair of first through holes 45 located on the handle shaft 35 side and a pair of second through holes 46 located on the steering shaft 34 side. The pair of first through holes 45 and the pair of second through holes 46 are arranged side by side in the rotational axis X direction.

As shown in FIGS. 3 and 4, one of the pair of first through holes 45 is a threaded first female screw hole 47, and the other of the pair of first through holes 45 is a screw. The first round hole 48 is not cut. One of the pair of second through holes 46 is a threaded second female screw hole 49, and the other of the pair of second through holes 46 is a non-threaded second round hole 50. It has become.

3, 4, and 6, the shaft end portion 37 of the handle shaft 35 is provided with a first engagement recess 51 that is retracted from the outer peripheral end portion of the handle shaft 35. The first engagement recess 51 is formed on the outer peripheral portion of the deformed fitting portion 52 with the coupling mechanism 36 in the handle shaft 35. The odd-shaped fitting portion 52 is provided with a first male spline portion 53 that is fitted to the first female spline portion 42 of the boss member 39. The first engaging recess 51 is provided in the middle of the first female spline portion 42 in the rotation axis X direction. In other words, the first engagement recess 51 is sandwiched between the male splines of the odd-shaped fitting portion 52 in the rotation axis X direction. The first engaging recess 51 is a circumferential groove extending over the entire outer periphery of the handle shaft 35. The first through holes 45 extending inside and outside the boss member 39 are provided at locations corresponding to the first engagement recesses 51 in the boss member 39.

As shown in FIGS. 3 and 4, the first engagement recess 51 and the first through hole 45 communicate with each other, whereby the insertion hole 54 located on the handle shaft 35 side corresponding to the outer peripheral shape of the first key member 40. Is configured. In other words, the first engagement recess 51 and the first through hole 45 communicate with each other, so that an insertion hole 54 that extends tangentially is formed in the outer peripheral portion of the deformed fitting portion 52 in the handle shaft 35.

The first key member 40 shown in FIG. 2 to FIG. 4 and FIG. 6 is inserted into the first engagement recess 51 and the first through hole 45, and is inserted into both the first engagement recess 51 and the first through hole 45. The relative movement between the boss member 39 and the handle shaft 35 in the rotation axis X direction is restricted by engaging. Further, the first key member 40 is a fastener that is inserted and clamped from one side to the other side across the cut 44 in the boss member 39. The first key member 40 is provided with a first head portion 55 and a first shaft portion 56 that is connected to the first head portion 55. The first shaft portion 56 is provided with a first male screw portion 57 that can be screwed into the first female screw hole 47. The first key member 40 is screwed into the first female screw hole 47 with the first male screw portion 57 so as to narrow the cut 44 and reduce the diameter of the boss member 39 by being pinched with the first head 55. A fastening force along the tangential direction is applied.

As shown in FIGS. 3, 5, and 6, the shaft end portion 38 of the steering shaft 34 is provided with a second engagement recess 58 that is retracted from the outer peripheral outer end portion of the steering shaft 34. The second engagement recess 58 is formed on the outer peripheral portion of the deformed fitting portion 59 with the coupling mechanism 36 in the steering shaft 34. The odd-shaped fitting portion 59 is provided with a second male spline portion 60 that fits into the second female spline portion 43 of the boss member 39. The second engagement recess 58 is provided in the middle of the second male spline portion 60 in the rotation axis X direction. In other words, the second engagement recess 58 is sandwiched between the male splines of the odd-shaped fitting portion 59 in the rotation axis X direction. The second engaging recess 58 is a circumferential groove extending over the entire outer periphery of the steering shaft 34. The second through hole 46 extending inside and outside the boss member 39 is provided at a location corresponding to the second engagement recess 58 in the boss member 39.

As shown in FIGS. 3 and 5, the second engagement recess 58 and the second through hole 46 communicate with each other, whereby the insertion hole 61 located on the steering shaft 34 side corresponding to the outer peripheral shape of the second key member 41. Is configured. In other words, the second engagement recess 58 and the second through hole 46 communicate with each other, so that an insertion hole 61 that extends tangentially is formed in the outer peripheral portion of the deformed fitting portion 59 in the steering shaft 34.

The second key member 41 shown in FIGS. 2, 3, 5, and 6 is inserted into the second engagement recess 58 and the second through hole 46, and the second engagement recess 58 and the second through hole 46 are And the relative movement between the boss member 39 and the steering shaft 34 in the direction of the rotational axis X is restricted. The second key member 41 is a fastener that is inserted and clamped from one side to the other side across the cut 44 in the boss member 39. The second key member 41 is provided with a second head portion 62 and a second shaft portion 63 provided continuously with the second head portion 62. The second shaft portion 63 is provided with a second male screw portion 64 that can be screwed into the second female screw hole 49. The second key member 41 is formed by screwing the second male screw portion 64 into the second female screw hole 49 so as to narrow the cut 44 and reduce the diameter of the boss member 39 by being pinched with the second head 62. A fastening force along the tangential direction is applied.

As shown in FIG. 2, in the vicinity of the upper end portion of the hollow frame 32 in the handle shaft 35, for example, a rubber vibration isolating member 65 interposed between the handle shaft 35 and the hollow frame 32 is interposed. . An annular upper regulating member 66 is provided on the upper side of the vibration isolating member 65. A lower regulating member 67 is provided below the vibration isolating member 65. An upper retaining ring 68 is detachably attached to the inner periphery of the hollow frame 32 on the upper side of the upper restricting member 66. A lower retaining ring 69 is detachably attached to the outer periphery of the handle shaft 35 below the lower regulating member 67. The upper retaining ring 68, the upper restricting member 66, the vibration isolating member 65, the lower restricting member 67, and the lower retaining ring 69 prevent the handle shaft 35 from being pulled upward with respect to the hollow frame 32.

[Assembly of the handle shaft to the steering shaft]
As shown in FIG. 2, the coupling mechanism 36 can be operated from the opening 70 of the hollow frame 32. First, as shown in FIG. 6, the boss member 39 is spline fitted to the shaft end portion 38 of the steering shaft 34 from above. Then, the second key member 41 is inserted across the first through hole 45 of the boss member 39 and the second engagement recess 58 of the steering shaft 34, and the second male screw portion 64 of the second key member 41 is inserted into the second key member 41. Screwed into the female screw hole 49. Next, the shaft end portion 37 of the handle shaft 35 is spline fitted to the boss member 39 from above. Then, the first key member 40 is inserted across the second through hole 46 of the boss member 39 and the first engagement recess 51 of the handle shaft 35, and the first male screw portion 57 of the first key member 40 is moved to the first. Screwed into the female screw hole 47. At this time, the steering shaft 34 and the boss member 39, and the boss member 39 and the handle shaft 35 are connected by spline fitting, respectively, and the first engagement recess 51 and the second engagement recess 58 are surrounded. It is a groove. For this reason, the phase relationship between the steering shaft 34 and the boss member 39 and the phase relationship between the boss member 39 and the handle shaft 35 can be freely selected to some extent, so that the handle shaft 35 can be easily assembled to the steering shaft 34. .

4 and 5, as the first key member 40 and the second key member 41 are screwed together, the cut 44 of the boss member 39 is reduced, and the boss member 39 is reduced in diameter. At this time, a fastening force acts in a tangential direction on the cut 44 in the outer peripheral portion of the boss member 39, so that the boss member 39 is uniformly contracted, and between the boss member 39 and the steering shaft 34, and between the boss member 39 and A clearance due to fastening is less likely to occur between the handle shaft 35 and the handle shaft 35.

[Another embodiment]
Hereinafter, another embodiment in which the above embodiment is modified will be described. A plurality of different embodiments can be selected and applied to the above embodiments as long as no contradiction occurs. The scope of the present invention is not limited to the contents shown in each embodiment.

(1) In the above embodiment, an example in which the insertion hole 54 extending in a tangential shape is formed in the outer peripheral portion of the odd-shaped fitting portion 52 is not limited thereto. For example, as shown in FIG. 7, an insertion hole 154 that extends in the normal direction in the odd-shaped fitting portion 52 may be formed. In this case, the handle shaft 35 is provided with a first engagement recess 135 having a round hole shape that constitutes the insertion hole 154 together with the first through hole 45, and the first key member 40 moves the first engagement recess 135. It will penetrate. In this case, the first engagement recess 135 may be a female screw hole instead of a round hole.

(2) In the above embodiment, an example in which the insertion hole 61 extending in a tangential shape is formed in the outer peripheral portion of the odd-shaped fitting portion 59 is not limited thereto. For example, as illustrated in FIG. 8, an insertion hole 161 extending in the normal direction may be formed on the outer peripheral portion of the odd-shaped fitting portion 59. In this case, the steering shaft 34 is provided with a second engagement recess 134 having a round hole shape that constitutes the insertion hole 161 together with the second through hole 46, and the second key member 41 has the second engagement recess 134. It will penetrate. In this case, the second engagement recess 134 may be a female screw hole instead of a round hole.

(3) In the said embodiment, although the 1st external thread part 57 of the 1st key member 40 illustrated what extends over the substantially full length of the axial part of the 1st key member 40, it is not restricted to this. . For example, the first male screw portion 57 of the first key member 40 may be formed only in a length portion corresponding to the first female screw hole 47 of the boss member 39.

(4) In the said embodiment, although the 1st key member 40 illustrated what is a fastener, it is not restricted to this. For example, the first key member 40 may be a headed pin in which the first male screw portion 57 is not provided. In this case, it is possible to prevent it from coming off by inserting an engagement piece into the tip of the headed pin.

(5) In the above-described embodiment, the second male screw portion 64 of the second key member 41 is illustrated as extending over substantially the entire length of the shaft portion of the second key member 41, but is not limited thereto. . For example, the second male screw portion 64 of the second key member 41 may be formed only in a length portion corresponding to the second female screw hole 49 of the boss member 39.

(6) In the above embodiment, the second key member 41 is exemplified as a fastener, but is not limited thereto. For example, the second key member 41 may be a headed pin on which the second male screw portion 64 is not provided. In this case, it is possible to prevent it from coming off by inserting an engagement piece into the tip of the headed pin.

(7) In the above embodiment, one of the pair of first through holes 45 is a threaded first female screw hole 47, and the other of the pair of first through holes 45 is threaded. Although the thing which has become the 1st round hole 48 which is not illustrated is illustrated, it is not restricted to this. For example, the pair of first through holes 45 may be round holes that are not threaded. In this case, a nut for screwing the first male screw part 57 is separately provided outside the boss member 39.

(8) In the above embodiment, one of the pair of second through holes 46 is a threaded second female screw hole 49, and the other of the pair of second through holes 46 is threaded. Although the thing which is not the 2nd round hole 50 is illustrated, it is not restricted to this. For example, the pair of second through holes 46 may be round holes that are not threaded. In this case, a nut for screwing the second male screw portion 64 is separately provided outside the boss member 39.

(9) In the above embodiment, the first female spline part 42 and the second female spline part 43 are illustrated as a continuous female spline part, but the present invention is not limited to this. For example, the first female spline portion 42 and the second female spline portion 43 may be a continuous female spline portion having different phases.

(10) In the above embodiment, the deformed fitting portion 59 in the steering shaft 34 is illustrated as being provided with the second male spline portion 60, but is not limited thereto. The modified fitting between the steering shaft 34 and the boss member 39 may be another mode. For example, the odd-shaped fitting portion 59 in the steering shaft 34 may have a non-circular cross section, and the boss member 39 may be provided with a portion to be fitted into the odd-shaped fitting portion 59. In this case, various types such as an oval type and a square type can be adopted as the non-circular cross section.

(11) In the above embodiment, an example in which the first male spline portion 53 is provided in the deformed fitting portion 52 in the handle shaft 35 is illustrated, but the present invention is not limited thereto. The variant fitting between the handle shaft 35 and the boss member 39 may be another mode. For example, the odd-shaped fitting part 52 in the handle shaft 35 may have a non-circular cross section, and the boss member 39 may be provided with a portion to be fitted into the odd-shaped fitting part 52. In this case, various types such as an oval type and a square type can be adopted as the non-circular cross section.

(12) In the above embodiment, the first engaging recess 51 is illustrated as being sandwiched between the male splines of the odd-shaped fitting portion 52 in the rotational axis X direction. I can't. For example, the 1st engagement recessed part 51 may be provided in the location which is not pinched | interposed into the male spline of the deformed fitting part 52 in the rotation axis X direction.

(13) In the above embodiment, the second engagement recess 58 is illustrated as being sandwiched between the male splines of the odd-shaped fitting portion 59 in the rotational axis X direction. I can't. For example, the second engaging recess 58 may be provided at a location that is not sandwiched between the male splines of the deformed fitting portion 59 in the rotation axis X direction.

(14) In the above embodiment, the boss member 39 is illustrated as being made of ductile cast iron, but is not limited thereto. For example, the boss member 39 may be made of the same material as the handle shaft 35 and the steering shaft 34 or other materials.

(15) In the above embodiment, the hollow frame 32 whose upper end is opened is illustrated, but the present invention is not limited to this. For example, a lid member that closes the upper end of the hollow frame 32 may be provided to prevent entry of dust, rainwater, or the like into the hollow frame 32.

(16) In the above embodiment, an example in which the lops frame 17 is provided is illustrated, but the present invention is not limited to this. For example, instead of the lops frame 17, a cabin that covers the boarding space of the operator may be provided.

The present invention can be used for various work vehicles such as a combine and a rice transplanter in addition to the tractor.

16: Steering handle 28: Steering mechanism 34: Steering shaft 35: Steering shaft 36: Coupling mechanism 37: Steering shaft shaft end 38: Steering shaft shaft end 39: Boss member 40: First key member 41: First Two key members 44: cut 45: first through hole 46: second through hole 51: first engagement recess 52: deformed fitting portion 54 on handle shaft: insertion hole 58 on the handle shaft side: second engagement recess 59 : Different shape fitting part 61 in the steering shaft: Insertion hole X on the steering shaft side: Turning axis

Claims

A handle shaft coupled to the steering handle;
A steering shaft disposed on the same rotation axis as the handle shaft and operating a steering mechanism;
A coupling mechanism that is deformed and fitted to the handle shaft and the steering shaft and connects the handle shaft and the steering shaft so as to rotate integrally around the rotation axis;
A tubular boss member provided in the coupling mechanism across the handle shaft and the steering shaft, and through which a shaft end portion of the handle shaft and a shaft end portion of the steering shaft are inserted, and the boss member And a first key member attached in a state extending over the handle shaft, and a second key member attached in a state extending over the boss member and the steering shaft,
A first engagement recess is formed in the outer peripheral portion of the deformed fitting portion with the coupling mechanism in the handle shaft, and inside and outside of the boss member at a position corresponding to the first engagement recess in the boss member. A first through hole is formed, and the first engagement recess and the first through hole communicate with each other, thereby forming an insertion hole corresponding to the outer peripheral shape of the first key member,
The first key member is inserted into the first engagement recess and the first through hole, and engages with both the first engagement recess and the first through hole, so that the rotation axis direction Restricting relative movement between the boss member and the handle shaft in
A second engagement recess is formed in the outer peripheral portion of the deformed fitting portion with the coupling mechanism in the steering shaft, and extends to the inside and outside of the boss member at a position corresponding to the second engagement recess in the boss member. A second through hole is formed, and the second engagement recess and the second through hole communicate with each other, thereby forming an insertion hole corresponding to the outer peripheral shape of the second key member,
The second key member is inserted into the second engagement recess and the second through hole, and engages with both the second engagement recess and the second through hole to rotate in the rotational axis direction. A work vehicle that restricts relative movement between the boss member and the steering shaft.
The first engaging recess is a circumferential groove extending over the entire outer periphery of the handle shaft, and the second engaging recess is a circumferential groove extending over the entire outer periphery of the steering shaft. Work vehicle as described in.
The boss member is configured in a C-shaped cross section having a cut in the circumferential direction,
3. The work vehicle according to claim 1, wherein the first key member and the second key member are fasteners that are inserted and clamped from one side to the other side across the cut.
The first engaging recess and the first through hole are pierced through the outer periphery of the odd-shaped fitting portion of the handle shaft as a result of the communication between the first engaging recess and the first through hole. Is configured to form,
The second engagement recess and the second through hole are pierced through the outer periphery of the deformed fitting portion of the steering shaft by the second engagement recess and the second through hole communicating with each other. The work vehicle according to any one of claims 1 to 3, wherein the work vehicle is configured to be formed.