JP2001097237A - Steering device for tractor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steering mechanism for a tractor which will not be changed in its steering performance even if the tread width is varied. SOLUTION: A double-rod steering cylinder 10 is laterally provided on an axle case 11 of a tractor, and knuckle arms 13, 13 are connected to the tips of the piston rods 10a, 10a of the steering cylinder through tie rods 12, 12 to steer and turn front wheels. In the configuration where the tread is varied by replacement with an axle case having a different length, spacers 25, 25 according to the varied length of the axle case are interposed between the piston rods 10a, 10a and joints 23, 23, and the spacers 25, 25 are extended coaxially with the piston rod.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an arrangement of a steering section of a power steering apparatus using a double rod type hydraulic cylinder.

[0002]

2. Description of the Related Art Conventionally, a double axle type steering cylinder is arranged in a front axle case, a tie rod is connected to the tip of a piston rod on both sides of the steering cylinder, and a knuckle arm is connected to the tip of the tie rod for steering. A configuration in which a wheel (a front wheel) can be steered by turning is known.

[0003]

In such a conventional steering mechanism, when the tread width is increased, the tie rods at both ends of the piston rod are replaced by separate members to increase the tread width. When the tread width is changed in this way, after the change, when the front wheel is turned by operating the steering wheel, and when turning around the connecting portion between the piston rod and the tie rod, the front wheel While the cutting angle of the front wheel is small, the front wheels come into contact with the gear cases, which are the power transmission portions at both ends of the front axle case, and the cutting angles of the front wheels are regulated until the piston rod comes into contact with the gear case. For this reason, the turning angle of the front wheel cannot be made large, and the turning radius of the tractor becomes large.

[0004]

The present invention uses the following means in order to solve the above problems. That is, a double-rod type steering cylinder is provided laterally on the axle case of the tractor and connected to the knuckle arm via a tie rod at the tip of the piston rod of the steering cylinder so that the front wheels can be steered and rotated. In a configuration in which the tread is changed by replacing the axle case with a different axle case, a spacer corresponding to the changed length of the axle case is interposed between the piston rod and the joint.

The spacer extends on the same axis as the piston rod.

[0006]

Next, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a plan view showing the entire configuration of the tractor, FIG. 2 is a plan view showing the front wheels and the steering mechanism when the vehicle travels straight when the tread is narrow, and FIG. 3 is a plan view showing the front wheels and the steering mechanism when the vehicle is turning left. FIG. 4 is a plan view showing a conventional front wheel and steering mechanism during straight running when the tread width is widened, FIG. 5 is a plan view showing a front wheel and steering mechanism during a left turn when the conventional tread width is widened, and FIG. FIG. 7 is a plan view showing the front wheels and the steering mechanism when the tread width is widened according to the present invention, and FIG. 7 is a plan view showing the front wheels and the steering mechanism when turning left when the tread width is widened according to the present invention.

As shown in FIG. 1, a tractor as a traveling vehicle 1 has front wheels 2.2 and rear wheels 3 at front and rear portions, respectively.
3 is suspended, and an engine is mounted in a hood 6 at a front portion of the traveling vehicle 1, and a driving force is extracted from the engine to drive the front wheels 2.2 and the rear wheels 3.3. A steering handle 8 is disposed behind the hood 6, and a driver seat 7 on which an operator rides is disposed behind the steering handle 8.
Is provided, and the work machine mounting device 9 is disposed at the rear.

Next, the tractor steering mechanism will be described. The front wheels 2, 2 serving as the steered wheels are disposed on both sides of the front axle case 11, and a transmission shaft for driving the front wheels 2, 2 is supported in the front axle case 11, as shown in FIG. The front axle case 11 is divided into three parts in the left-right direction, and a center case 11M and a left axle case 1 protruding to both sides thereof.
1L and a light axle case 11R, which are joined and fixed on both sides of a center case 11M with bolts and the like, and the front axle case 11 is supported on a body frame by a center pin so as to be able to swing left and right.

A steering cylinder 10 for power steering is provided horizontally on the center case 11M in the left-right direction. The steering cylinder 10 is a double-rod double-acting cylinder having piston rods 10a projecting to both sides. , The piston rod 10a
The tip of the tie rod 12a is connected to the tip of the tie rod 12 via a spherical joint 23.
Is connected to the knuckle arms 13.

The other side of the knuckle arms 13 is fixed to a wheel support portion 14 of the front wheels 2. The wheel support portion 14 is rotatably supported on the kingpin of the rotating case 20. The wheel supporting portion 14 rotatably supports a wheel mounting portion 15 connected to an axle, and as shown in FIGS. 2 and 3, the wheel mounting portion 15
The front wheel 2 is driven by a transmission shaft in the front axle case 11 via a transmission shaft and gears in the rotating case 20 so that the front wheels 2 can be rotationally driven. The wheel support 14
The pressure oil is supplied to the steering cylinder 10 via the power steering valve by the rotation of the steering wheel, the piston rods 10a, 10a are slid left and right, and the front wheel 2 is moved through the spherical joint 23, the tie rod 12, and the knuckle arm 13.・ 2 can be steered by turning left and right.

Next, the change of the tread width of the front wheel will be described. In FIG. 2, assuming that the tread width of the front wheels 2, 2 is L1, conventionally, when the tread width L1 is increased, FIG.
As shown in FIG. 5, the width of the shaft between the front wheels 2 and the width of the front axle case 11 is increased to 11 ′, the tread width L1 is changed to L2, and the tie rods 12 are formed accordingly. The length of 12a and 12a was changed to 12'a and 12'a.

That is, the right axle case 11R and the left axle case 1 are bolted to both ends of the center case 11M of the front axle case 11.
1L is replaced with a separately long axle case 11'R, 11'L, or the front axle case 11 and the front wheels 2, 2 arranged at both ends of the front axle case 11
The tread width is widened by interposing a joint member between the gear case 19 and the gear case 19 serving as a power transmission mechanism for the vehicle.
Also, the tie rods 12 use tie rods 12 ', 12' which are separately long rack ends 12a.

Thus, the tie rods 12 ', 12'
As shown in FIG. 5, the steering wheel 8 is operated to turn off the front wheels 2, 2 and the tie rods 12 ', 1
When the 2 'rotates around the spherical joints 23, the gear cases 19 at both ends of the front axle case 11' are formed while the turning angle of the front wheels 2.2 is small during the rotation.
-It becomes impossible to rotate due to contact with 19, and the cut angle of the front wheels 2 is regulated to be smaller than that in the case where the tread is narrow. For this reason, the turning angle of the tractor becomes large because the angle of the front wheels 2 cannot be made large.

Therefore, when the tread width L1 is increased in the present invention, as shown in FIG. 6, the front axle case 11 is made up of a right axle case 11R and a left axle case 11L, as shown in FIG. Replace with 11 "R ・ 11" L and widen,
Alternatively, the front axle case 11 and the gear case 1
The tread width is widened by interposing a joint member between the treads 9 and 19. Then, spacers 25 are connected to both ends of the piston rods 10a.
25 is connected to the spherical joints 23 at the other end.

That is, the spacers 25 are formed in a cylindrical shape and have the same length as the width of the front axle case 11 which is widened. One end of each of the spacers 25 is screwed to the tip of the piston rod 10a. The spacers 25 and the piston rods 10a extend so as to extend on the same axis. The other ends of the spacers 25 are connected to the piston rods 10a
a of the spherical joint 23
・ 23 can be connected as it is. Thus, the tread width L1 is L by the length of the spacers 25.
It spreads to three.

By connecting the spherical joints 23 via the spacers 25 to both ends of the piston rods 10a without changing the lengths of the tie rods 12 in this manner, conventionally, as shown in FIG. Like the front wheel 2
2 has become shallower, and the tie rods 12 ', 12' abut on the gear cases 19, 19, thereby restricting the angle of the front wheels 2, 2. As shown in FIG. In the link mechanism of (1), the piston rod 10a is slidably displaced in the left-right direction in accordance with the operation of the handle. The relative positional relationship among the spherical joint 23, the tie rod 12, the knuckle arm 13, and the gear case 19, which are the pivot points, The problem that the above-mentioned angle of cut becomes shallow due to the fact that the front wheel 2 does not change can be solved.
2) The turning angle of the steering wheel 8 is almost the same, showing the same turning property, and since the relationship between the operation amount of the steering wheel 8 and the cutting angle of the front wheels 2 2 is not changed, it is easy for the operator to operate and fatigue. It does not.

[0017]

According to the present invention, the following effects can be obtained by the configuration described above. That is, as in claim 1, a double rod type steering cylinder is laterally mounted on the axle case of the tractor and connected to a knuckle arm via a tie rod at the tip of the piston rod of the steering cylinder to steer the front wheel. In the configuration in which the tread is changed by replacing the axle case with a different length of axle case, a spacer corresponding to the changed length of the axle case is interposed between the piston rod and the joint. The correlation between the operation amount of the steering wheel and the turning angle of the front wheel does not change before and after the tread width (front wheel width) is changed, so that the operator can operate with the same feeling before and after the change, and is easy to operate. And they don't get tired.

Further, since the spacer extends on the same axis as the piston rod, a link of a steering mechanism formed by a hydraulic cylinder, a tie rod, or the like can be separately provided with different dimensions. It is not necessary to replace the tread, the same parts can be used, the cost can be reduced, and the tread width can be easily changed by inserting a spacer, so that it is possible to easily cope with the specifications of various types of tractors.

[Brief description of the drawings]

FIG. 1 is a plan view showing the entire configuration of a tractor.

FIG. 2 is a plan view showing front wheels and a steering mechanism when the vehicle travels straight when the tread is narrow.

FIG. 3 is a plan view showing a front wheel and a steering mechanism during a left turn.

FIG. 4 is a plan view showing a front wheel and a steering mechanism during straight traveling when the tread width is widened according to the related art.

FIG. 5 is a plan view showing a front wheel and a steering mechanism when turning left when the tread width is widened in the related art.

FIG. 6 is a plan view showing the front wheels and the steering mechanism during straight traveling when the tread width is widened according to the present invention.

FIG. 7 is a plan view showing the front wheels and the steering mechanism when turning left when the tread width is widened according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Running vehicle 2 Front wheel 3 Rear wheel 4 Steering mechanism 8 Steering handle 10 Steering cylinder 10a Piston rod 11 Front axle case 12 Tie rod 13 Knuckle arm 16 King pin 23 Spherical joint 25 Spacer L1 Tread width L2 Tread width (at the time of conventional widening) L3 tread width (at the time of widening in the present invention)

Claims (2)

[Claims] 1. A two-rod type steering cylinder is provided laterally on an axle case of a tractor and connected to a knuckle arm via a tie rod at a tip of a piston rod of the steering cylinder so that a front wheel can be steered and rotated. At the same time, in the configuration to change the tread by replacing with the axle case of different length,
A steering device for a tractor, wherein a spacer corresponding to a changed length of the axle case is interposed between a piston rod and a joint. 2. The tractor steering apparatus according to claim 1, wherein the spacer extends on the same axis as the piston rod.