JP2003276657A - Crawler type traveling device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To change a tread of a crawler type traveling device in a simple constitution. <P>SOLUTION: This crawler type traveling device is so constituted that the center in the rotary axis direction of a sprocket 12 is offset from a fitting part 42 of the sprocket 12 to a drive shaft 26 in the rotary axis direction, and the sprocket 12 it turned over and attached to the drive shaft 26, so that the position of the center in the rotary axis direction of the sprocket 12 is changed to the rotary axis direction. This traveling device is provided with a cylinder part 54 where a swinging shaft 22 is inserted and which is axially movable and supported to turn around the axis, regulating members 57 and 59 provided in the side of the swinging shaft 22, engaged with axial both sides of the cylinder 54, and regulating the axial movement of the swinging shaft 22, and a spacer 53 selectively interposed between one regulating member 57 and the axial end face of the cylinder part 54, or between the other regulating member 59 and the axial end face of the cylinder part 54. This constitution can axially change the position of the swinging shaft 22. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crawler type traveling device capable of changing a tread.

[0002]

2. Description of the Related Art Conventionally, for example, a crawler unit (semi crawler) is used instead of a rear wheel tire of a four-wheel drive tractor.
A semi-crawler belt tractor in which the left and right are independently attached is described in Japanese Patent Application Laid-Open No. 11-321729. The crawler unit includes an upper sprocket, a track frame disposed below the sprocket, an idler provided in front of and behind the track frame, and a plurality of rolling wheels provided between the front and rear idlers of the track frame. , The sprocket, the idler, and an endless belt-shaped crawler belt wound around the rolling wheels, and by rotating the sprocket,
The crawler belt is circulated around the circumference.

In the crawler unit according to this conventional example, the tread cannot be changed.

[0004]

In the semi-crawler track tractor, for example, a transplanting device, a tillage weeding device, a harvesting device, etc. are mounted, and while running across a ridge, management work (cultivation, Weeding, etc.) and transplanting / harvesting work, etc.By using this semi-crawler tractor for upland fields, it is possible to prevent slips, especially when used on slopes or when it rains. There is an advantage that work can be performed well. When this semi-crawler tractor is used in a field, since the width of the ridge differs depending on the crop, it is necessary to change the tread corresponding to the width of the ridges (the groove between the ridges).

Therefore, as a means for changing the tread of the crawler unit, a structure in which the rear axle case to which the crawler unit is attached can be expanded and contracted in the left-right direction and expanded and contracted by a hydraulic cylinder or the like is conceivable. The rear axle case needs to be highly rigid in order to support the weight of the vehicle body and the implements mounted on the vehicle body, and because the traction force due to the work acts on the rear axle case. However, a considerable amount of reinforcement is required, which makes the weight heavier, and when it becomes heavier, there is a problem that the soil is hardened and the cost is high, and the structure is complicated.

In view of the above problems, it is an object of the present invention to provide a crawler type traveling device which can change the tread with a simple structure.

[0007]

The technical means taken by the present invention to solve the technical problem is to attach a sprocket to a drive shaft that is rotationally driven, and rotate the sprocket to rotate the sprocket. In a crawler type traveling device in which a wrapped crawler belt is circulated and circulated in a circumferential direction, a sprocket is attached to a drive shaft so that a position of the sprocket can be changed in a rotational axis direction. And

In the above structure, the center of the sprocket in the direction of the rotation axis is offset in the direction of the rotation axis from the mounting portion of the sprocket with respect to the drive shaft, and the sprocket is turned over and attached to the drive shaft, whereby the sprocket is rotated. It can be configured to be repositioned in the axial direction. In addition, the sprocket is mounted and fixed to the drive shaft, the side wheels provided on both the left and right sides of the mounting wheel, and the crawler belt provided on the outer peripheral side between the left and right side wheels and engaging with the crawler belt. It is preferable that the side wheels on both the left and right sides are detachable from the mounting wheel, and the engaging members can be replaced by removing the side wheels.

The sprocket may be divided into a plurality of pieces in the circumferential direction. Further, as the crawler type traveling device, a track frame is arranged below the sprocket,
Attach idlers and wheels to this truck frame,
A crawler type traveling device is adopted in which a crawler belt wound around a sprocket, an idler, and a rolling wheel is circulated and circulated in a circumferential direction by rotationally driving a sprocket. Another technical means is to place the track frame below the sprocket,
Attach idlers and wheels to this truck frame,
A crawler type traveling device in which a crawler belt wound around a sprocket, an idler, and a rolling wheel circulates in a circumferential direction by rotationally driving a sprocket. In a crawler type traveling device that is swingably supported about an axis parallel to the rotation axis of the sprocket, the idler and the rolling wheels are rotated by changing the position of the swing axis in the axis direction. The feature is that the position can be changed in the axial direction.

Further, the swing shaft is inserted, and the swing shaft is provided with a tubular portion which is movable in the axial direction and is rotatably supported around the axial center. Is provided on both sides in the axial direction of the rocking shaft so as to restrict the movement of the swing shaft in the axial direction, and between the one regulatory part and the axial end face of the tubular portion, or the other. By providing a spacer that is selectively interposed between the restricting portion and the end surface of the tubular portion in the axial direction, the position of the swing shaft can be changed in the axial direction. Another technical means is to mount a sprocket on a rotationally driven drive shaft, arrange a track frame below the sprocket, install an idler and a wheel on the track frame, and rotate the sprocket. , A sprocket, an idler, and a crawler belt wound around a rolling wheel are configured so as to circulate and rotate in the circumferential direction, and the track frame has an axis parallel to the axis of rotation of the sprocket via a swing axis. In a crawler type traveling device which is swingably supported around, a sprocket is attached to a drive shaft so that the position thereof can be changed in the direction of the rotation axis, and the swing shaft is positioned in the direction of the axis. The position of the idler and the wheel can be changed in the direction of the rotation axis of the sprocket by changing the position.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. In FIG. 3, reference numeral 1 is a semi-crawler tractor (vehicle) in which a crawler unit 2 (semi-crawler) is independently provided in place of a rear wheel of a four-wheel drive tractor, and a front wheel 7 is a steering wheel. This tractor 1
Exemplifies a tractor with a cabin in which a cabin 4 is mounted on a rear portion of a vehicle body 3, a driver's seat 5 is provided in a rear portion of the cabin 4, and a steering handle 6 is provided in front of the driver's seat 5. Has been.

The vehicle body 3 is constructed by attaching a power transmission case 9 to the rear portion of the engine 8 via a flywheel housing, and the power transmission case 9 is constituted by a clutch housing, a transmission case and the like. Front wheel 7
The front axle case is provided on both left and right sides of the front axle case supported by the front axle frame 10, and the front axle case is attached to and fixed to the front axle frame 10 fixed to the engine 8 so as to project forward from the engine 8. It is swingably supported by. As shown in FIG. 2, the crawler unit 2 is attached to the rear end side of the power transmission case 9 (transmission case) and the outer end side of the rear axle case 19 (axle case) provided in a projecting direction in the left and right direction. Has been.

In FIG. 2, the left and right crawler units 2 are not shown. As shown in FIGS. 1 and 2, the crawler unit 2 includes one sprocket 12, a pair of front and rear idlers 13, a plurality of (four in the present embodiment) rolling wheels 14, and these sprockets 12 ,.
The sprocket 12 includes a crawler belt 15 wound around the idler 13 and the rolling wheels 14, a track frame 16, and a transmission case 17 (gear case).
The crawler belt 15 is circulated and circulated in the circumferential direction by rotationally driving the shaft around the axis in the left-right direction, and the crawler belt 15 is thereby configured to travel.

First, the structure of the crawler unit 2 will be roughly described. The track frame 16 is composed of a rectangular tubular body and is arranged along the front-rear direction. A wheel 14 is supported. The idler 13 is arranged in front of and behind the track frame 16, and the rolling wheels 14 are arranged below the track frame 16 in the front-rear direction. The sprocket 12 is arranged above the track frame 16 and above the middle portion between the front and rear idlers 13, and is supported by the transmission case 17.

The transmission case 17 is attached and fixed to the outer side of the rear axle case 19 at the rear of the vehicle body 3 in the left-right direction.
A support portion 21 is provided below the transmission case 17, and a swing shaft 22 is supported by the support portion 21 so as to be rotatable about an axis in the left-right direction. A track frame 16 is attached to the track frame 16, and the track frame 16 together with the idler 13 and the rolling wheels 14
It is swingably supported around the axis of the swing shaft 22.

The crawler unit 2 is integrally and detachably attached to the rear axle case 19 as a unit. The main body of the crawler belt 15 is formed of rubber in an endless belt shape, and rubber drive projections 23 are provided on the inner peripheral side thereof at appropriate intervals in the circumferential direction and over the circumferential direction. The drive protrusion 23 is provided with the sprocket 1
2 has a function of circumferentially engaging with the sprocket 12 to receive a driving force, and laterally engaging with the rolling wheel 14, the sprocket 12 and the idler 13 to prevent derailment (to prevent the crawler belt 15 from coming off). ) Has a function.

The center O of the sprocket 12 in the direction of the rotation axis X and the center P of the rollers 14 and the idler 13 in the direction of the rotation axis Z are the center of the crawler belt 15 in the left-right direction (width direction) and the left-right direction. Match in direction (Figs. 6 and 7)
And FIG. 9). Next, the configuration of the crawler unit 2 will be described in detail. As shown in FIG. 4, a rear axle 25 (axle) in the left-right direction is provided in the lower portion of the transmission case 17, and a drive shaft 26 is provided in parallel with the rear axle 25 in the upper portion of the transmission case 17. Between the rear axle 25 and the drive shaft 26,
An intermediate shaft 27 is provided in parallel with these.

The rear axle 25 and the intermediate shaft 27 are arranged around the left and right axial centers via bearings between the left and right outer side walls of the transmission case 17 and the left and right outer end side wall portions of the rear axle case 19. It is rotatably supported by. The drive shaft 26 is
Between the outer wall and the inner wall in the left-right direction of the transmission case 17, the bearing is rotatably supported around the axis in the left-right direction via bearings, and protrudes outward from the transmission case 17 in the left-right direction. A flange portion 28 is provided on the protruding end portion, and the sprocket 12 is attached and fixed to the flange portion 28.

The rear axle 25 is provided with a first gear 29, the drive shaft 26 is provided with a second gear 30, and the intermediate shaft 27 is provided with these first and second gears 29, 30. A meshing idler gear 31 is provided, and power is transmitted from the rear axle 25 to the drive shaft 26 by a gear transmission mechanism (power transmission mechanism) including the first gear 29, the second gear 30, and the idler gear 31, and a sprocket is obtained. 12 is rotationally driven around the axis of the drive shaft 26. In the structure described above, the sprocket 12 is arranged so that the rotation axis X of the sprocket 12 is located above the axis Y of the rear axle 25 that transmits power to the sprocket 12. As a result, the contact angle (contact range) of the crawler belt 15 with respect to the sprocket 12 can be increased, whereby the number of meshing teeth (in the portion of the crawler belt 15 wound around the sprocket 12
The meshing member 4 that engages with the drive protrusion 23 of the sprocket 12
0 (which means the number of meshing parts) can be increased, the load load acting from the meshing member 40 of the sprocket to the drive projection 23 is reduced, the life of the crawler belt 15 is extended, and the speed of the crawler is increased. The unit 2 can be provided.

In the present embodiment, the meshing member 40
Are provided, four of which are drive protrusions 2.
It is designed to mesh with 3. The rear axle 25 is protruded inward in the left-right direction from the transmission case 17, and is interlocked with the transmission shaft 32 in the rear axle case 19 via a coupling 33. On the other hand, the power from the engine 8 is transmitted to the rear wheel differential device via the clutch via the speed change mechanism in the power transmission case 9, from which the left and right rear axle cases 1 are transmitted.
The power is branched to the transmission shaft 32 in 9 and the left and right transmission shafts 3
Power is transmitted from 2 to the rear axle 25.

A brake device for braking the transmission shaft 32 (sprocket 12) is provided on the left and right inner ends of the rear axle case 19. The drive shaft 26 is located above the rear axle 25 in the vertical direction, and the swing shaft 22 is located below the rear axle 25 in the vertical direction. As shown in FIGS. 5 and 6, the sprocket 12 is a ring-shaped attachment wheel 3 that is attached and fixed to the flange portion 28 of the drive shaft 26.
8, ring-shaped side wheels 39 located on both the left and right sides of the mounting wheel 38, and a meshing member 40 that meshes with the drive projection 23 of the crawler belt 15.
It is divided into two in the circumferential direction (hence the mounting wheel 3
8 and the left and right side wheels 39 are divided into two in the circumferential direction).

The sprocket 12 may or may not be divided into three or four parts in the circumferential direction. Also, when replacing the crawler belt 15,
With one sprocket assembly 12A located at the top and the other sprocket assembly 12B located at the bottom of the sprocket 12, the lower sprocket assembly 12B
The crawler belt 15 is loosened and the crawler belt 15 can be replaced by rotating the sprocket assembly 12A located on the upper side and rotating it to the lower side.

The mounting wheel 38 has a cylindrical portion 41 that is concentric with the rotation axis X of the sprocket 12, and a mounting flange 42 (mounting portion) that projects radially inward from the inner peripheral surface of the cylindrical portion 41. . On the other hand, the flange portion 28 of the drive shaft 26
A mounting seat 43 is formed on the outer peripheral side of the outer surface in the left-right direction of
The mounting flange 43 of the mounting wheel 38 is attached to the mounting seat 43.
To penetrate the mounting flange 42,
The mounting wheel 38 is detachably mounted and fixed to the drive shaft 26 by the stud bolt 44 screwed into the screw hole formed in the above and the nut 45 screwed into the stud bolt 44.

The mounting flange 42 is used for the sprocket 1
It is provided with a size A offset from the center O of the sprocket 12 in the X-axis direction (the center O of the sprocket 12 in the X-axis direction is the mounting flange 42).
Is offset in the left-right direction from the center R in the left-right direction). Therefore, the sprocket 12 is turned over (turned left and right) from the mounting state shown in FIG.
By attaching to the flange portion 28 of the drive shaft 26 (one of the left and right surfaces of the attachment flange 42 of the sprocket 12).
Of the flange portion 28 of the sprocket 1 by abutting against the mounting seat 43 and the other side of the mounting flange 42 abutting on the mounting seat 43).
The position of the rotary shaft center 2 in the X direction (horizontal direction) can be changed with a simple structure. With this structure and a structure for changing the position of the idler 13 and the rolling wheels 14 in the horizontal direction, which will be described later, Left and right crawler unit 2 treads T1, T2
Can be changed.

The mounting flange 4 of the sprocket 12
2 and the flange portion 28 of the drive shaft 26 by interposing a ring-shaped spacer or the like, the sprocket 1
The position of the second rotation axis X in the X direction may be changeable. The inner peripheral portion 46 of the side wheel 39 has the mounting wheel 3
The left and right side wheels 39 are detachably attached to and fixed to the attachment wheel 38 by attachment bolts 47 that come into contact with the side surfaces of the cylindrical portion 41 of No. 8 and penetrate the inner peripheral portion 46 and are screwed into the cylindrical portion 41. ing.

The outer peripheral portions 48 of the left and right side wheels 39 are projected outward in the radial direction with respect to the mounting wheels 38, and the outer peripheral portions 48 of the left and right side wheels 39 have a bottomed cylindrical shape on the facing surface. The shaft support holes 49 are formed at intervals in the circumferential direction. Further, on the outer peripheral portion 48 of the left and right side wheels 39,
A flange portion 50 is formed that extends outward in the left-right direction (opposite side) and contacts the inner peripheral surface of the crawler belt 15. The meshing member 40 is composed of a pin, and is composed of a cylindrical large-diameter engagement portion 51 at the center in the axial direction, and a small-diameter shaft portion 52 projecting outward in the left-right direction from both left and right sides of the engagement portion 51. The left and right shaft portions 52 are removably inserted into the shaft support holes 49 of the side wheel 39, and the meshing member 40
Are sandwiched between the left and right side wheels 39, and are attached and held.

Therefore, by removing the outer side wheel 39 from the mounting wheel 38, the meshing member 40
Can be removed from between the side wheels 39, and the meshing member 40 can be replaced. Further, since the sprocket 12 is divided in the circumferential direction, when the engagement member 40 is replaced, the structure of the side wheel 39 on the side where the crawler belt 15 is not wound (lower side) is removed. Thus, the side wheel 39 can be easily removed.

Further, the meshing member 40 includes the side wheel 39.
Since the plurality of engaging members can be replaced by removing the engaging members, the engaging members can be easily replaced as compared with the case where the engaging members are attached one by one. Further, a bush is externally fitted to the shaft portion 52, and a shim is interposed in the inner portion of the shaft support hole 49, and the meshing member 40 is rotatably supported around the axis in the left-right direction. As a result, wear due to contact with the drive projection 23 is reduced and uneven wear is prevented.

That is, when the sprocket 12 is rotationally driven, the driving projection 23 of the crawler belt 15 is relatively inserted between the meshing members 40 on the outer peripheral portion of the sprocket 12, and the meshing member 40 contacts the driving projection 23. , Meshing, torque is transmitted from the sprocket 12 to the drive projection 23,
At this time, since the meshing member 40 is rotatable, wear due to contact with the drive projection 23 is small and uneven wear is prevented. Although the inner side wheel 39 may be integrally formed with the mounting wheel 38, the inner side wheel 39 and the outer side wheel 39 can be manufactured at a low cost by using a common shape.

Further, since the left and right side wheels 39 are detachably attached to the mounting wheel 38, the meshing member 40 can be replaced even if either the left or right surface of the sprocket 12 is mounted on the drive shaft 26. To be done. Further, as described above, the sprocket structure 1 located on the lower side
After removing 2B, the sprocket 12 can be easily removed from the drive shaft 26 by rotating the drive shaft 26 to position the sprocket component 12A located on the upper side on the lower side. Easy to do.

The meshing member 40 may be composed of a shaft provided between the outer peripheral portions 48 of the left and right side wheels 39, and a collar externally fitted to the shaft so as to be rotatable around the shaft center. In this case, the collar serves as an engaging portion that abuts the drive protrusion 23. Further, even in the sprocket 12 in which the flange portion 50 protruding outward in the left-right direction is provided on the outer peripheral side of the side wheel 39, the meshing member 40 should be sandwiched between the left and right side wheels 39 to be attached and fixed. By this, the meshing member 40 can be provided as close to the outer periphery of the sprocket 12 as possible, whereby the meshing member 12 is driven.
Can be engaged with the base side of the.

As shown in FIGS. 4, 7 and 8, the support portion 21 for supporting the swing shaft 22 has a tubular portion 54 having a horizontal axis, and the tubular portion 54 is integrated with the transmission case 17. And a connecting rib 55 that physically connects them. The swing shaft 22 is inserted into the cylindrical portion 54 from the outer side in the left-right direction and is supported rotatably around the axis in the left-right direction. Note that grease is injected between the swing shaft 22 and the cylindrical portion 54. On the side of the end surface 54a on the inner side in the left-right direction of the tubular portion 54, a cover plate 57 is provided via a ring-shaped collar 56 and a ring-shaped (cylindrical) spacer 53 that are externally fitted to the swing shaft 22 in a removable manner. The (regulator) is abutted (engaged).

The cover plate 57 is in contact with the end face 22a on the inner side in the left-right direction of the swing shaft 22, and is screwed into a screw hole 68 formed in the swing shaft 22 through the cover plate 57. The cover plate 57 is fixed to the swing shaft 22 by the bolts 58 that are mounted on the swing shaft 22.
Movement to the outside in the left-right direction with respect to the tubular portion 54 is restricted (the swing shaft 22 is prevented from coming off from the tubular portion 54). The collar 56 is arranged so as to contact the end surface 54a on the inner side in the left-right direction of the tubular portion 54, and the spacer 53 is interposed between the collar 56 and the cover plate 57.

The width B of the spacer 58 in the left-right direction is
Is formed to have a size twice the offset amount A of the center O of the sprocket 12 in the direction of the rotation axis X from the center R of the mounting flange 42 in the left-right direction. The swing shaft 22 is the tubular portion 5.
It protrudes outward in the left-right direction from the outer end side in the left-right direction of 4,
The left and right outer ends of the swing shaft 2 are located on the track frame 1
It is located above 6 and below sprocket 12. A pair of inner and outer flanges 59 and 60 in the left-right direction are inserted through the outer end side of the swing shaft 22 in the left-right direction, and the inner flange 59 (restriction portion) can be inserted into and removed from the swing shaft 22. It is abutted (engaged) with the end face 54b on the outer side in the left-right direction of the tubular portion 54 of the support portion 21 via a ring-shaped collar 65 fitted on the outside.

The inner flange 59 is fixed by welding or the like to a fixing plate 61 fixed to the upper surface of the track frame 16 by welding or the like, and the outer flange 6 is
0 is fixed to the swing shaft 22 by a connecting member 62 fixed to the outer flange 60 and the swing shaft 22 by welding or the like. Further, the inner and outer flanges 59 and 60 are joined to each other by bolts 63 which penetrate the outer flange 60 and are screwed into the screw holes formed in the inner flange 59, whereby the track frame 16 swings. The support portion 21 is swingably supported around the axis in the left-right direction via a moving shaft 22.

Further, with the above structure, the swing shaft 22
Movement inward in the left-right direction with respect to the tubular portion 54 is also restricted. In the structure described above, the cover plate 57 is removed from the swing shaft 22, the spacer 53 is removed from the swing shaft 22, and then the cover plate 57 is attached and fixed to the swing shaft 22 again. The moving shaft 22 is movable leftward and rightward, and the swinging shaft 22 is moved leftward and rightward by interposing the removed spacer 53 between the collar 65 and the inner flange 59. It can be positioned at the above-mentioned position.

In this way, the spacer 53 is attached to the collar 56.
By selectively interposing between the cover plate 57 and the cover plate 57 or between the collar 65 and the inner flange 59, the swing shaft 22 has a simple structure and has the same size as the sprocket 12 in the left-right direction. The position of the idler 13 and the roller 1 mounted on the track frame 16 can be changed by changing the position of the swing shaft 22 in the left-right direction.
4 will be repositioned together. Therefore, by changing the position of the sprocket 12 in the left-right direction and changing the position of the swing shaft 22 in the left-right direction, the left-right crawler unit 2 is moved.
Treads T1 and T2 (distance between the centers of the crawler belts 15 of the left and right crawler units 2 in the left-right direction (the direction of the rotation axis X of the sprocket 12) can be changed.

When changing the tread, the positions of the sprockets 12, the idler 13 and the rolling wheels 14 of the left and right crawler units 2 are changed in the left and right directions. In addition,
The spacer 53 includes the collars 56 and 65 and the end surface 5 of the tubular portion 54.
4a, 54b, and the cover plate 57 and the inner flange 59 can be directly contacted with the tubular portion 54, and the cover plate 57 and the tubular portion end surface 54a.
The spacer 53 may be interposed between the inner flange 59 and the cylindrical end surface 54b.

The fixed plate 61 is projected from the track frame 16 inward in the left-right direction, and a reinforcing member 64 is provided between the protruding portion and the wall part inward in the left-right direction of the track frame 16. . Further, abutting portions 36 projecting outward in the radial direction are provided in front of and behind the tubular portion 54, and the abutting portions 36 are provided on either of the pair of front and rear stoppers 37 provided on the inner flange 59. By abutting against each other, the swinging of the swinging shaft 22 of the track frame 16 or the like is restricted around the axis.

A mounting plate 66 for mounting the rolling wheels 14 is fixed to the lower surface side of the track frame 16 by welding or the like, and a screw hole 67 is attached to the mounting plate 66 from the lower side.
Are formed. On the other hand, the rolling wheel 14 includes a tubular portion 70 having a horizontal axis, a support shaft 71 inserted through the tubular portion 70 and rotatably supported around the horizontal axis via a bearing, and a tubular body. The support shaft 7 is arranged on both left and right sides of the portion 70.
It is configured by a ring body 72 which is fitted on the outer periphery of the first body and is prevented from coming off.

The cylindrical portion 70 is located above the drive projection 23, and the left and right wheels 72 are located on both the left and right sides of the drive projection 23 and rolls on the inner peripheral surface of the crawler belt 15. .
In addition, a mounting bracket 73 that abuts the lower surface of the mounting plate 66 is integrally extended to the cylindrical portion 70, and the mounting bracket 73 penetrates the portion of the mounting bracket 73 that abuts the mounting plate 66 to provide a mounting plate. The rolling wheels 14 are detachably attached to the track frame 16 by bolts 74 screwed into the screw holes 67 of 66.

Further, since the sprocket 12 is arranged so that its rotation axis X is located above the axis Y of the rear axle 25, a large space below the sprocket 12 can be provided. As a result, the wheel unit including the wheel 14 and the mounting bracket 73 can be attached to the lower surface side of the track frame 16 from below.
The lower space of the track frame 16 can be made sufficiently large (the height of the track frame 16 can be made large), and the wheel unit can be detachably mounted and fixed to the lower surface of the track frame 16 to mount the wheel 14 The strength is ensured.

The idler 13 on the front side is the crawler belt 1.
The tension adjusting device 75 is fixed to the front portion of the track frame 16 by being rotatably supported by a bracket 76 provided on the tension adjusting device 75 for adjusting the tension of the No. 5 shaft. Further, the rear idler 13 is supported by a bracket 77 fixed to the rear end side of the track frame 16 so as to be rotatable around the axis in the left-right direction. As shown in FIG. 9, the front and rear idlers 13 are supported by a tubular portion 79 having a left-right axial center and a tubular portion 79 inserted through the tubular portion 79 and rotatably supported around a horizontal axial center through bearings. And a wheel body 81 that is disposed on both left and right sides of the tubular portion 79 and that is fitted onto the support shaft 80 and is prevented from coming off. The left and right wheel bodies 81 are the drive projections 23. Are located on the left and right sides of the crawler belt 15 and roll on the inner peripheral surface of the crawler belt 15.

Further, as shown in FIG. 8, the front wheel 1
The mounting plate 66 for mounting 4 is thinner than the mounting plate 66 for mounting the other rolling wheels 14 in the up-down direction, and the height of the lower end of the rolling wheel 14 on the front end side from the grounding surface is different. The roller 14 on the front end side is attached to the track frame 16 so as to be higher than the lower end of the roller 14 by L. The height of the lower ends of the front and rear idlers 13 from the ground contact surface is also higher than that of the lower ends of the rolling wheels 14 other than the rolling wheels 14 on the front end side.
They are mounted so that they are respectively higher by M1 and M2.

In the crawler unit 2, when traveling on a soft ground (soft ground) such as a field, the crawler belt 15 is, for example, substantially directly below the shaft 80 of the idler 13 on the front side (in the vicinity immediately below). To the support shaft 80 of the idler 13 on the rear side
It will be grounded almost directly below (near the bottom), but on the paved road surface,
The crawler belt 15 is grounded in a range E substantially directly below the support shaft 71 of the second wheel 14 from the front to just below the support shaft 71 of the rear end-side transfer wheel 14. That is, the ground contact length of the crawler belt 15 (ground contact area, or the range in which the load from the vehicle body 3 acts) is shorter on the paved road surface between the soft ground and the paved road surface. Thus, it is configured so that the vehicle can easily turn when traveling on the paved road surface.

The vehicle adopting the present invention may be one having a crawler unit attached instead of the front wheels, one having four crawler units independently attached instead of the front and rear four wheels, and the like. Good. Swing axis 2
The support portion 21 that supports 2 may be provided integrally with or separately from the rear axle case 19. Also, the sprocket 12
May be attached to the rear axle 25, in which case
The rear axle 25 serves as a drive shaft.

[0047]

According to the present invention, it is possible to provide a crawler type traveling device capable of changing a tread with a simple structure.

[Brief description of drawings]

FIG. 1 is a side view of a crawler unit.

FIG. 2 is a rear sectional view of a rear portion of the tractor.

FIG. 3 is a side view of the tractor.

FIG. 4 is a rear cross-sectional view of the upper portion of the crawler unit.

FIG. 5 is a side view of a sprocket.

FIG. 6 is a front sectional view of a sprocket.

FIG. 7 is a rear cross-sectional view of the lower portion of the crawler unit.

FIG. 8 is a side view of the lower portion of the crawler unit.

FIG. 9 is a sectional view of an idler.

[Explanation of symbols]

12 sprockets 13 idlers 14 wheels 15 crawler belt 16 truck frame 21 Support 22 Swing axis 26 Drive shaft 38 mounting wheel 39 side wheels 40 mating member 42 Mounting flange (mounting part) 53 Spacer 54 Tube 54a Tube end face 54b Cylindrical end face 57 Cover Plate (Regulator) 59 Inner Flange (Regulator) O Sprocket center of rotation axis X sprocket rotation axis direction

Claims (8)

[Claims] 1. A crawler type traveling device in which a sprocket is attached to a rotationally driven drive shaft and the sprocket is rotationally driven so that a crawler belt wound around the sprocket is circulated and circulated in a circumferential direction. The crawler type traveling device, wherein the sprocket is attached to the drive shaft so that the position of the sprocket can be changed in the direction of the rotation axis. 2. The center of the sprocket in the direction of the axis of rotation is
It is offset from the mounting part of the sprocket to the drive shaft in the direction of the rotation axis, and it is configured so that the sprocket can be repositioned in the direction of the rotation axis by turning the sprocket upside down and attaching it to the drive shaft. The crawler type traveling device according to claim 1. 3. A sprocket, wherein a sprocket is attached and fixed to a drive shaft, side wheels provided on both left and right sides of the attachment wheel, and a crawler belt provided on an outer peripheral side between the left and right side wheels. It has a meshing member that engages and transmits torque, side wheels on both left and right sides are detachable from the mounting wheel, and the meshing member can be replaced by removing the side wheels. The crawler type traveling device according to claim 2. 4. The crawler type traveling device according to claim 1, wherein the sprocket is divided into a plurality of pieces in the circumferential direction. 5. A track frame is arranged below the sprocket, an idler and a rolling wheel are attached to the track frame, and the sprocket is driven to rotate, whereby a crawler belt wound around the sprocket, the idler, and the rolling wheel is formed. The crawler type traveling device according to any one of claims 1 to 4, wherein the crawler type traveling device is configured so as to circulate around in a circumferential direction. 6. A track frame is arranged below the sprocket, an idler and a rolling wheel are attached to the track frame, and the sprocket is driven to rotate, whereby a crawler belt wound around the sprocket, the idler, and the rolling wheel is formed. A crawler-type traveling device configured to circulate around in a circumferential direction, in which a track frame is swingably supported around an axis parallel to a rotation axis of a sprocket via an oscillation axis. In the device, the crawler type traveling device is characterized in that the position of the idler and the rolling wheel can be changed in the rotational axis direction of the sprocket by changing the position of the swing shaft in the axial direction. 7. A cylinder portion, through which the swing shaft is inserted, the swing shaft being axially movable, and supported rotatably around the shaft center. Is provided on both sides in the axial direction of the rocking shaft so as to restrict the movement of the swing shaft in the axial direction, and between the one regulatory part and the axial end face of the tubular portion, or the other. By providing a spacer that is selectively interposed between the restricting portion and the axial end surface of the tubular portion,
The crawler type traveling device according to claim 6, wherein the swing shaft is capable of changing its position in the axial direction. 8. A sprocket is attached to a rotationally driven drive shaft, a track frame is arranged below the sprocket, an idler and a rolling wheel are attached to the track frame, and the sprocket is rotationally driven.
The crawler belt wound around the sprocket, idler, and rolling wheels is configured to circulate around in the circumferential direction, and the track frame is rotated about the axis parallel to the axis of rotation of the sprocket via the swing axis. In a crawler-type traveling device that is swingably supported on the sprocket, the sprocket is attached to the drive shaft so that the position of the sprocket can be changed in the direction of the rotation axis, and the position of the swing shaft is changed in the direction of the axis. By doing so, the position of the idler and the wheel can be changed in the direction of the rotational axis of the sprocket, and the crawler type traveling device is characterized.