JPH08113047A - Front wheel drive device of tractor - Google Patents

Abstract

PURPOSE: To prevent an upper part of a wheel shaft case from trying to fall down outward in the lateral direction due to a high load acting on the wheel shaft case to support front wheels (steered wheels) in a four wheel drive tractor. CONSTITUTION: A shaft part 33 is protrusively arranged on the upper side in an upper part of a gear case 14, and a support member 34 is rotatably supported around the axis of a king pin 21 with this shaft part 33, and a connecting part 37 coming into contact with a part 38 to be connected arranged in the upper part of a wheel shaft case 23 by facing in the lateral direction, is arranged in this support member 34, and the part 38 to be connected is fastened to the connecting part 37 by a lateral directional bolt 41.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a front wheel drive device for a tractor.

[0002]

2. Description of the Related Art In a four-wheel drive tractor, the upper portion of a gear case is fixed to the left and right ends of a front wheel differential case having a differential gear, and a king pin and a pair of interlocking gears are arranged in the gear case. Bevel gear is supported,
Among these bevel gears, one bevel gear is fixed to the protruding end side of the differential yoke shaft that projects outward in the left-right direction from the differential device, and the other bevel gear is fixed to the upper part of the kingpin.

Further, a lower cylinder portion of the axle case is externally fitted to a lower cylinder shaft portion of the gear case from below through a pair of upper and lower bearings so that the axle case is rotatable about an axis of the king pin. It is supported. Inside the axle case, an axle to which the front wheels are fixed and a pair of bevel gears are supported, one bevel gear is fixed to the lower part of the king pin, and the other bevel gear is fixed to the axle, and the power from the differential is applied to the front wheels. And the front wheels are steerable.

[0004]

In the above-mentioned conventional one, the lower cylinder portion of the axle case is cantilevered by the lower cylinder shaft portion of the gear case by a pair of upper and lower bearings. Therefore, due to the high load that acts on the axle case when working, a force is applied to the upper portion of the axle case to lie outward in the left-right direction, and stress concentrates on the supported portion of the axle case, There is a problem that it affects the durability of the case.

Therefore, in view of the above problems, the present invention has as its main object to prevent the sagging of the axle case.

[0006]

The technical means taken by the present invention to achieve the above-mentioned object is that the kingpin 2 is provided at the left and right ends of the front wheel differential case 9 having the differential gear 10 therein.
1, and the upper part of the gear case 14 having a bevel gear mechanism for interlockingly connecting the upper part of the king pin 21 and the differential yoke shaft 12 protruding outward in the left-right direction from the differential device 10 is fixed, and the lower part of the gear case 14 is fixed. Cylinder shaft 18
The axle 22 to which the front wheels 5 are fixed, and the axle 22
And the lower portion of the king pin 21 are interlockingly connected to each other.
In a front wheel drive device of a tractor rotatably fitted and supported around a shaft center of a kingpin 21 from a lower side, a shaft portion 33 is provided on an upper portion of the gear case 14 so as to project upward, and a support member 34 is provided on the shaft portion 33. Is rotatably supported around the axis of the king pin 21, and the support member 34 is provided with a connecting portion 37 that faces the connected portion 38 provided in the upper portion of the axle case 23 in the left-right direction. The point is that the connected portion 38 is fastened to the connecting portion 37 with the left and right bolts 41.

[0007]

The supporting member 34 is rotatably supported around the shaft center of the king pin 21 on the shaft portion 33 protruding from the upper portion of the gear case 14, and the support member 34 is connected to the connected portion provided on the upper portion of the axle case 23. 38 is provided with a connecting portion 37 that faces the left-right direction and abuts, and the connected portion 38 is fastened to the connecting portion 37 by a left-right bolt 41, so that the axle due to the high load acting on the axle case 23. Case 23
The sagging is effectively prevented, and the rigidity of the axle case 23 is improved.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 3 shows an overall side view of the tractor 1. The tractor 1 includes a transmission case 3 having an engine 2, a flywheel housing, a clutch, a transmission and the like.
A vehicle body 4 is mainly configured by directly connecting the above, and the vehicle body 4 is supported by a pair of left and right front wheels (steering wheels) 5 and rear wheels 6.

The rotational power of the engine 2 is a clutch,
It is transmitted to the left and right rear wheels 6 via the main transmission mechanism, the forward / reverse switching mechanism, the auxiliary transmission mechanism, the creep transmission mechanism, the rear wheel differential device, and the like, and the power is extracted from the input shaft to the rear wheel differential device. The power can be taken out through the gear, and the power can be transmitted from the power take-out gear through the front wheel propulsion shaft 7 to the front wheel differential device.

A front axle frame 8 is provided so as to project from the engine 2 forward, a front wheel differential case 9 is disposed in the left-right direction on the lower surface side of the front axle frame 8, and the center portion of the front wheel differential case 9 in the left-right direction is the front-rear direction. It is swingably supported around the axis of. As shown in FIG. 4, the front wheel diff case 9 is provided with a diff storage case 11 at the center in the left-right direction having a front wheel differential device 10 and left and right sides of the diff storage case 11 projecting outward in the left-right direction. The differential device 10
And a cylindrical yoke shaft case 13 that accommodates the differential yoke shaft 12 that protrudes to the left and right. The front wheel differential gear 10 is connected to the propulsion shaft 7 that transmits the power extracted from the input shaft to the rear wheel differential gear.

A gear case 14 is provided at an outer end portion in the left-right direction of each yoke shaft case 13 of the front wheel differential case 9.
As shown in FIG. 1, the gear case 14 includes an upper bevel gear accommodating portion 17 for accommodating a bevel gear mechanism including a pair of bevel gears 15 and 16 meshing with each other, and a left and right direction extending downward from the bevel gear accommodating portion 17. It is composed of a lower cylindrical shaft portion 18 which is inclined so as to move outward.

The bevel gear housing 17 is a yoke shaft case 1.
The outer end of the differential yoke shaft 12 is inserted into the accommodating portion 17, and the bevel gear 15 in the bevel gear accommodating portion 17 is spline-fitted to the outer end portion of the diff yoke shaft 12. The bevel gear 15 is rotatably supported on the inner surface of the differential yoke shaft 12 insertion opening of the gear case 14 via a bearing 19.

The other bevel gear 16 in the bevel gear accommodating portion 17 is supported on the upper end side of the cylinder shaft portion 18 of the gear case 14 via a bearing 20 and is also provided with a kingpin 21 concentrically arranged in the five cylinder shaft portion 18. The kingpin 21 projects downward from the lower end opening of the tubular shaft portion 18 by being spline-fitted and fixed to the upper part of the. An axle case 23 that rotatably supports the axle 22 is arranged outside each of the left and right gear cases 14. The axle case 23 is open outward and is fitted onto the gear case 14 from below, and the king pin 21 is supported by a pair of upper and lower bearings 24 and 25.
The main body portion 26 has a tubular portion 26a that is rotatably supported around the shaft center, and the lid portion 27 fixed to the main body portion 26 so as to close the outer end opening.

The axle 22 is projected from the lid portion 27 and has a flange 28 at the projecting end, and the front wheel 5 is attached to the flange 28.
The wheel 29 of is attached. A bevel gear 30 spline-fitted to the lower end side of the king pin 21 is rotatably supported via a bearing 31 at the lower end of the tubular portion 26a of the axle case body 26, and the bevel gear 30 is spline-fitted to the axle 22. The combined bevel gear 32 is engaged.

Therefore, the rotational power from the front wheel differential gear 10 is transmitted from the differential yoke shaft 12 to the bevel gears 15 and 16.
Is transmitted to the king pin 21 through the bevel gears 30, 32 from the king pin 21 to the axle 22 to rotate the front wheel 5, and the front wheel 5 can be steered around the axis of the king pin 21. Has been done. On the upper part of the gear case 14, the kingpin 2 is integrally provided so as to extend upward from the central part of the upper surface of the bevel gear accommodating part 17.
1 is provided with a shaft portion 33 that is concentric with the main body portion 26 of the axle case 23 via a support member 34.
Are connected to increase the rigidity of the main body 26.

The support member 34 is externally fitted to the shaft portion 33 via a bush 35 so as to be rotatable about its axis, and has a cylindrical main body portion 36 with its upper end closed, and an integral body from this main body portion 36. It is composed of a pair of front and rear connecting portions 37 extending in the direction. Further, on the upper portion of the main body portion 26 of the axle case 23, the connecting portion 37 and a pair of front and rear connected portions 38 which are brought into contact with and face each other in a direction orthogonal to the axial direction of the shaft portion 33 are integrally provided. ing. The connecting portion 37 has a bolt insertion hole 3
9 is formed so as to penetrate in the facing direction of the connected portion 38, and a screw hole 40 is formed in the connected portion 38 in the facing direction of the connected portion 38.
The connected portion 38 is connected to the connecting portion 37 by a horizontal bolt (UBS bolt) 41 screwed into the.

The body portion 36 and the shaft portion 33 of the support member 34
An oil seal 42 is provided at a lower end portion between and, a hole 43 is formed at the center of the upper surface of the main body 36 of the support member 34, and a grease nipple 44 is fitted in the hole 43. . By removing the grease nipple 44 when the support member 34 is fitted to the shaft portion 33,
The hole 43 acts as an air vent hole to facilitate mounting.

[0018]

According to the present invention, the shaft portion 33 is provided on the upper portion of the gear case 14 so as to project upward, and the support member 34 is rotatably supported around the shaft center of the king pin 21 on the shaft portion 33. Since the connecting portion 37 of the support member 34 and the connected portion 38 provided on the upper portion of the axle case 23 are fastened by the bolts 41, the flexure of the axle case 23 due to the high load acting on the axle case 23 is effectively prevented. However, the rigidity of the axle case 23 can be increased without significantly increasing the weight.

Further, when the connecting portion of the support member and the connected portion of the axle case are vertically faced and brought into contact with each other, and these are fastened with a bolt in the vertical direction, shear stress acts on the bolt, and However, in the present invention, in particular, the connecting portion 37 of the support member 34 may be damaged.
And the connected portion 38 of the axle case 23 is faced to and abutted against the connected portion 38 in the left-right direction, and the connected portion 38 is fastened to the connecting portion 37 by the bolt 41 in the left-right direction, so that no shear stress acts on the bolt 41, The strength is secured.

[Brief description of drawings]

FIG. 1 is a rear cross-sectional view of a main part.

FIG. 2 is a plan view of a main part.

FIG. 3 is an overall side view of a tractor.

FIG. 4 is a schematic view of a front wheel drive device in which a central portion is shown in a plane cross section and one of the left and right sides is shown in a back cross section.

[Explanation of symbols]

 5 front wheel 9 front wheel differential case 10 differential device 12 differential yoke shaft 14 gear case 18 cylinder shaft portion 21 kingpin 22 axle shaft 23 axle case 26a cylinder portion 33 shaft portion 34 support member 37 connecting portion 38 connected portion 41 bolt

Claims (1)

[Claims] 1. A kingpin (21) at the left and right ends of a front wheel differential case (9) having a differential (10) therein.
And the upper part of the kingpin (21) and the differential (1
0) Diff yoke shaft (12) protruding laterally outward
An upper portion of a gear case (14) having a bevel gear mechanism for interlocking with and is fixed, and an axle (22) to which a front wheel (5) is fixed to a cylinder shaft portion (18) on the lower side of the gear case (14), And the axle (22) and the kingpin (2
The lower cylinder portion (26a) of the axle case (23) having a bevel gear mechanism that interlocks with the lower portion of (1) is externally fitted and supported from the lower side around the axis of the kingpin (21). In the front wheel drive device for a tractor, a shaft portion (33) is provided on an upper portion of the gear case (14) so as to project upward, and a support member (34) is provided around the shaft center of the kingpin (21). The support member (34) is rotatably supported, and the support member (34) is provided with a connecting portion (37) facing the connected portion (38) provided in the upper portion of the axle case (23) in the left-right direction and contacting the connected portion (37). A front wheel drive device for a tractor, characterized in that a connected portion (38) is fastened to a connecting portion (37) by a horizontal bolt (41).