JP3937634B2 - Tractor - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a tractor having a crawler in a traveling part.
[0002]
[Prior art]
Conventionally, as this type of tractor, a tractor described in JP-A-8-207836 is known. In the tractor described in this publication, a drive sprocket is attached to the rear axle end instead of the rear wheel, and a crawler is wound between the drive sprocket and a pair of front and rear driven wheels attached to a track frame on the vehicle body side. The crawler is rotated by the driving force of the sprocket to enable traveling.
[0003]
[Problems to be solved by the invention]
By the way, in the case of such a conventional device, since the driving sprocket has a smaller diameter than the rear wheel, the rotational speed of the rear axle does not change, but if the aircraft is run as it is, the peripheral speed of the front wheel is the rear running part. There was the drawback of being too fast. In order to prevent this, it is conceivable to incorporate a speed reducer in the mission case in advance and switch the speed reducer from the standard speed side to the speed reducing side when the rear wheel is replaced with a crawler. In this case, the existing mission case and the speed change mechanism have to be significantly modified, and it is expensive in terms of cost to design the transmission case in advance in the mission case.
[0004]
[Technical means for solving the problems]
The present invention is proposed in order to solve the above-mentioned drawbacks. The conventional transmission mechanism can be used as it is, and when changing from the wheel specification to the crawler specification, it can be handled with only a slight change. The operability is to provide a tractor that is the same as before. Therefore, the following technical measures were taken.
[0005]
That is, the drive sprocket (13) is attached to the rear axle (10), and the crawler (12) is wound around the drive sprocket (13) and driven wheels (21, 22) attached to the front and rear of the track frame (20), In the tractor configured to drive the crawler (12) by the drive sprocket (13) and to swingably support the front axle housing (46) by a pair of front and rear pivot bearing portions (47, 48), The axle housing (46) is provided with a pinion shaft (58) for driving the ring gear (57) of the front wheel differential device (17). The bearing boss (60) of the front axle housing (46) is provided with the pinion shaft (58). ) And an input shaft (62) on the same axis as the pinion shaft (58) side gear (59) and the input shaft (62) side gear (63). The front wheel speed reducer (55) is composed of a large diameter gear (64), a small diameter gear (65), and a counter gear (66) integrated with the small diameter gear (65) between the front wheel differential device (17) and A power steering cylinder (52) is disposed in the recess (50) formed in the front axle housing (46) between the ring gear (57) and the front wheel speed reducer (55), and the track frame (20 ) And the drive sprocket (13) can be configured to change the position in the lateral direction, keys (38, 38) are provided on the outer peripheral ends of the rear axles (10, 10). ) So that the cone cone member (40, 40) can slide in the axial direction, and the cone cone member (40, 40) is provided with a slit (41, 41) along the axial direction. The conical cone member (40, 40) is fitted with a fastener (42, 42) having a tapered inner surface on the outer peripheral portion thereof, and the conical cone member (40, 40) and the fastener (42, 42) The gap between the slits (41, 41) of the cone cone member (40, 40) is narrowed by tightening with a plurality of bolts (43, 43), and the cone cone member (40, 40) and the fastening tool (42). , 42) are fixed to the rear axles (10, 10) while integrating them, and the drive sprockets (13, 13) are flange portions (42a, 42a) of the fasteners (42, 42). The tractor is configured to be fastened and fixed with bolts (44, 44) .
[0006]
[Action]
The rotational power of the engine 2 is transmitted to the rear axle 10 via the transmission 5 in the transmission case 4, and the crawler 12 is rotationally driven by the drive sprocket 13 attached to the outer end portion of the rear axle 10. In the front axle housing 46 interposed between the pivot bearing portions 47 and 48, the front wheel is connected to the gear 59 on the pinion shaft 58 side and the gear 63 on the input shaft 62 side. The speed is greatly reduced by a front wheel speed reduction device 55 comprising a counter gear 66 integrated with a small diameter gear 65, and further reduced by a gear mechanism 70 in a final gear case 68. Thereby, the tractor can travel in a state where the front wheel 7 and the rear crawler 12 are substantially synchronized, and can easily travel in the field with a low ground pressure.
When the positions of the drive sprockets 13 and 13 are changed, the bolts 43 are loosened to widen the gaps between the slits 41 and 41, and the keys 38 and 38 in a state in which the fastening tool 42 and the conical cone member 40 are integrated. Slide up.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. First, the transmission system will be described. In FIG. 5, the rotational power of the engine 2 mounted on the front portion of the tractor 1 is transmitted to the transmission 5 in the transmission case 4 via the main clutch 3 and is decelerated by the transmission 5. The transmitted rotational power is transmitted to the front wheel 7 and the rear wheel 8.
[0008]
The transmission 5 includes a main transmission 5a and a sub-transmission 5b, each capable of shifting in four stages. The rear wheel 8 is detachably attached to the end of the rear axle 10, and when the crawler 12 is mounted instead of the rear wheel 8, the rear wheel 8 is removed from the rear axle 10 and a drive sprocket is attached to the end of the rear axle 10. 13 is attached. Since the outer diameter of the drive sprocket 13 is smaller than that of the rear wheel 8 (in this embodiment, the diameter of the drive sprocket is set to about ½ of the rear wheel diameter), the front and rear wheels are directly driven in a four-wheel drive state. Therefore, there arises a problem that the peripheral speed of the front wheel 7 is remarkably increased with respect to the rear wheel 8.
[0009]
Therefore, in the present invention, the speed reduction device 55 is incorporated between the pivot bearing portions that support the front axle housing 46 so as to reduce the rotational speed of the front wheels 7. The detailed structure of the reduction gear 55 will be described later. In FIG. 5, 15 is a rear wheel differential device, 17 is a front wheel differential device, 18 is a PTO transmission, and 19 is a PTO shaft. The power branched from the front of the rear wheel differential device 15 is transmitted to the front wheel drive shaft 11 via the gear mechanism 14.
[0010]
FIG. 1 is a side view of the tractor 1 changed from the rear wheel 8 to the crawler 12. In FIG. 1, driven wheels 21 are provided at the front and rear portions of the track frames 20, 20 provided along the front-rear direction. , 21, 22 and 22 are rotatably supported. Of these, the front driven wheels 21 are supported so as to be movable in the front-rear direction so that the tension of the crawler 12 can be adjusted. That is, when the pipes 26 and 26 that support the driven wheels 21 and 21 are moved to the front side, the crawlers 12 and 12 are stretched, and conversely, if the crawlers 12 and 12 are moved to the rear side, they are loosened.
[0011]
In addition, four rolling wheels 24, 24, 24, 24 are attached to the middle part of the track frames 20, 20 so as to be able to swing up and down around the swing shafts 23, 23, so that they can run unevenly on a field or road. The shock of time is absorbed. The left and right rear axles 10 and 10 are supported by bearings 27 and 27 on masts 25 and 25 fixed to the upper portions of the track frames 20 and 20, respectively.
[0012]
The track frames 20 and 20 are configured to swing up and down around the axis of the rear axles 10 and 10, and in this embodiment, the front end sides of the track frames 20 and 20 swing upward by 7 ° and downward by 5 °. It is configured to move. The swing of the track frames 20 and 20 is restricted by a stopper (not shown). FIG. 6 is a rear view of the masts 25 and 25 that support the rear axles 10 and 10. In this embodiment, the lateral positions of the track frames 20 and 20 and the drive sprocket 13 can be changed.
[0013]
More specifically, the outer axles of the rear axles 10 and 10 are provided with keys 38 and 38, and the conical cone members 40 and 40 can be slid along the keys 38 and 38 in the axial direction. ing. The conical cone members 40, 40 are provided with slits 41, 41 along the axial direction. The conical cone members 40, 40 are fitted with fastening tools 42, 42 having tapered inner surfaces on the outer peripheral portions thereof. By tightening the members 40, 40 and the fasteners 42, 42 with a plurality of bolts 43, 43, the gap between the slits 41, 41 of the conical cone members 40, 40 is narrowed. The conical cone members 40, 40 and the fasteners 42, 42 are integrated with each other while being fixed to the rear axles 10, 10. The drive sprocket 13 is fastened and fixed to the flange portion 42 a of the fastening tool 42 by a bolt 44.
[0014]
When the positions of the drive sprockets 13 and 13 are changed as in tread adjustment, the bolts 43 are loosened to widen the gaps between the slits 41 and 41, and the fastening tool 42 and the conical cone member 40 are integrated. In this state, the keys 38 and 38 are slid. Next, the speed reducer 55 incorporated in the front axle housing 46 will be described with reference to FIGS.
[0015]
In the figure, 45 is an axle bracket, 46 is a front axle housing, 47 is a front pivot bearing portion, and 48 is a rear pivot bearing portion. The front wheel differential device 17 is accommodated in the center portion in the width direction of the front axle housing 46, and the front axle housing 46 is supported by the two pivot bearing portions 47 and 48 so as to be swingable up and down. As shown in FIG. 2, the front axle housing 46 is provided with a recess 50 whose middle portion in the front-rear direction is recessed downward, and an orbit roll type power steering hydraulic cylinder 52 is disposed in the recess 50. When the piston rod 53 of the cylinder 52 moves in the horizontal direction, the knuckle arm 54 of the front wheel 7 is rotated to steer the front wheel 7. In this embodiment, hydraulic pressure is adopted as the cylinder, but it may be electric.
[0016]
Reference numeral 55 denotes a front wheel speed reducer provided on the back surface portion of the front axle housing 46 where the recess 50 is formed. A gear 59 is fixed to the rear end of the pinion shaft 58 that drives the ring gear 57 of the front wheel differential device 17, and a gear 63 is also fixed to the front end portion of the input shaft 62 that is supported in the bearing boss 60. The pinion shaft 58 and the input shaft 62 are concentric with each other, and a counter shaft 66 integral with the large diameter gear 64 and the small diameter gear 65 is attached to the sides of the shafts 58 and 62. The small diameter gear 65 meshes with the gear 59 on the pinion shaft 58 and transmits the rotational power decelerated to the front wheel differential device 17.
[0017]
In this embodiment, two sets of counter shafts 66 are provided. The power transmitted to the front wheel differential device 17 is further transmitted to the front wheel 7 via the gear mechanism 70 in the front wheel final gear case 68. Reference numeral 71 shown in FIG. 4 is a front axle. The final gear case 68 includes an inner case 68a fixed to the front axle housing 46 and an outer case 68b to be steered, and the piston rod 53 of the hydraulic cylinder 52 for power steering is moved in the left-right direction by operating the steering handle 72. When moved, the knuckle arm 54 attached to the tip of the knuckle is turned, and the outer case 68 b is turned around the axis of the king pin 69.
[0018]
In the above example, when the engine 2 is driven and decelerated by the transmission 5 in the transmission case 4, the reduced rotational power is transmitted to the rear axle 10 to rotate the drive sprocket 13. Then, the crawler 12 starts rotating and the machine body moves forward in a state in which the peripheral speed is about ½ slower than when the rear wheel 8 is mounted. As for the front wheel 7, the rotational power branched from the front of the rear wheel differential device 15 is transmitted. At this time, first, the power is transmitted from the propulsion shaft 16 for driving the front wheels to the input shaft 62, and the front axle housing. 46. The gear 63, the gear 64, the gear 65, and the gear 59 of the reduction device 55 at the back of the 46 are greatly decelerated. The rate of deceleration by the speed reducer 55 is about ½ of the normal rear wheel mounting type. Further, the speed is reduced by the gear mechanism 70 in the front wheel final gear case 68, and finally the front wheel 7 is rotated at a slightly higher peripheral speed than the peripheral speed of the crawler 12.
[0019]
In this embodiment, the steering hydraulic cylinder 52 is provided so as to extend laterally in a recess 50 formed in the rear portion of the front axle housing 46, and the speed reducer 55 that decelerates the front wheels 7. Is provided between the pair of front and rear pivot bearings 47, 48, so that the overall structure is simplified and the ground clearance is high, most of existing devices can be used as they are, and the front axle housing 46 can be used as it is. Since only a slight modification such as incorporating the speed reducer 55 is required, the cost is not increased and it can be manufactured at a low cost. Further, if the pivot bearing portions 47 and 48 are removed, the front axle housing 46 can be removed, and the inspection of the reduction gear 55 and the like can be simplified. Further, since the power steering cylinder 52 is interposed between the pivots without taking up any space, the steering operation is easy even though it is a crawler tractor.
[0020]
【The invention's effect】
As described above, according to the present invention, the drive sprocket (13) is attached to the rear axle (10), and the crawler (12) is attached to the drive sprocket (13) and the driven wheels (21, 22) attached to the front and rear of the track frame (20). ), The crawler (12) is driven by the drive sprocket (13), and the front axle housing (46) is swingably supported by a pair of front and rear pivot bearing portions (47, 48). In the tractor, the front axle housing (46) is provided with a pinion shaft (58) for driving the ring gear (57) of the front wheel differential device (17), and a bearing boss (60) portion of the front axle housing (46) is provided on the front axle housing (46). An input shaft (62) is provided concentrically with the pinion shaft (58), and the gear (59) and input shaft (62) on the pinion shaft (58) side are provided. A front wheel reduction device (55) is constituted by a large-diameter gear (64), a small-diameter gear (65), and a counter gear (66) integral with the small-diameter gear (65). A power steering cylinder (52) is disposed in the recess (50) formed in the front axle housing (46) between the ring gear (57) of the differential device (17) and the front wheel speed reducer (55). Therefore, a crawler specification tractor with a simple overall configuration, no manufacturing cost, and easy steering operation can be obtained.
Further, the position of the track frame 20 and the drive sprocket 13 in the lateral direction can be easily changed while firmly holding the track frame 20 and the drive sprocket 13.
[Brief description of the drawings]
FIG. 1 is an overall side view.
FIG. 2 is an enlarged side sectional view of a main part.
FIG. 3 is an enlarged plan sectional view of a main part.
FIG. 4 is a front view with a part cut away.
FIG. 5 is a power transmission diagram.
FIG. 6 is a rear view of a rear axle portion.
FIG. 7 is a perspective view of a main part.
[Explanation of symbols]
1 tractor 2 engine 3 main clutch 4 transmission case 5 transmission 7 front wheel 8 rear wheel 10 rear axle 12 crawler 13 driving sprocket 17 front wheel differential case 20 track frame 21 driven wheel 22 driven wheel 24 wheel
38 keys
40 cone cone member
41 slits
42 fasteners
42a flange
43 volts
44 bolt 46 front axle housing 47 pivot bearing 48 pivot bearing 52 power steering cylinder 55 front wheel speed reducer

Claims (1)

A drive sprocket (13) is attached to the rear axle (10), and a crawler (12) is wound around the drive sprocket (13) and driven wheels (21, 22) attached to the front and rear of the track frame (20) to drive the drive In the tractor configured to drive the crawler (12) by the sprocket (13) and to swingably support the front axle housing (46) by a pair of front and rear pivot bearing portions (47, 48),
The front axle housing (46) is provided with a pinion shaft (58) for driving the ring gear (57) of the front wheel differential device (17), and the pinion shaft is mounted on the bearing boss (60) of the front axle housing (46). An input shaft (62) is provided concentrically with (58), and a large-diameter gear (64) is interposed between the gear (59) on the pinion shaft (58) side and the gear (63) on the input shaft (62) side, A front wheel speed reducer (55) is constituted by the small diameter gear (65) and the counter gear (66) integrated with the small diameter gear (65), and the ring gear (57) and the front wheel speed reducer (55) of the front wheel differential device (17). and the recess formed in the front axle housing (46) (50) and configured to dispose the power steering cylinder (52) between the said track frame (20) and drive In order to make it possible to change the position of the procket (13) in the lateral direction, keys (38, 38) are provided on the outer peripheral ends of the rear axles (10, 10), and along the keys (38, 38). The cone cone member (40, 40) is configured to be slidable in the axial direction. The cone cone member (40, 40) is provided with slits (41, 41) along the axial direction, and the cone cone member (40, 40) is provided. 40) is fitted with a tapered fastener (42, 42) whose inner surface is tapered, and the conical cone member (40, 40) and the fastener (42, 42) are connected to a plurality of bolts (43). 43), the gap between the slits (41, 41) of the conical cone member (40, 40) is narrowed, and the conical cone member (40, 40) and the fastener (42, 42) are integrated. Fix these to the rear axle (10, 10) To configure such, drive sprocket (13, 13) is configured to fix fastening at the flange portion of the fastener (42, 42) (42a, 42a) on the bolt (44, 44) tractor.

Images