JP3172035B2 - Tractor steering system - Google Patents

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 drive unit in a power steering using a double rod type steering cylinder.

[0002]

2. Description of the Related Art Conventionally, a front axle case is provided with a double rod type steering cylinder, 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 tie rod tip. A configuration in which the can be rotated is known. For example, it is a technique disclosed in Japanese Utility Model Publication No. 3-12612.

[0003]

In such a conventional steering apparatus, the tie rod connected to the knuckle arm is not disposed on the extension of the piston rod of the steering cylinder. The tie rod end rotated around the kingpin in a plan view, and moved in a horizontal direction with a constant vertical width in a front view, and the tie rod end made a three-dimensional movement while receiving a large force from a cylinder. Therefore, a turning power is generated in the tie rod portion, and this turning power causes a problem that each screw portion is loosened in the link connecting portion. Further, the intersection angle between the tie rod and the piston rod is set to be minimum in a plan view, but the actual intersection angle is actually large because a vertical difference occurs. For this reason, the bending component force of the piston rod due to the tie rod reaction force during steering increases,
There was a problem that the piston rod was bent.

[0004]

The present invention uses the following means in order to solve the above problems. Tiger
Double rod type steering on front axle case 1 of Kuta
Place the ring cylinder 10 horizontally in the horizontal direction,
At both ends of the piston rod 10a of the
Knuckle arm 13.1 through tie rod 12.1
3 and the front wheels are steerable.
The piston rod 10a is slid in a front view of the straight
The tie rod 12 on the extension side when moved
Tyro that is substantially in line with the door 10a and is also on the extension side
The end trajectory of the rod 12 in the direction of the piston rod 10a.
With the kingpin angle β and the
The star angle α is substantially the same .

[0005]

By using such means, when the steering cylinder is slid during steering, the extension side of the piston rod pushes the tie rod and the knuckle arm, but is substantially parallel to the steering cylinder in a front view. Therefore, the component force in the direction perpendicular to the steering cylinder due to the reaction force of the tie rod is small, the force in the bending direction is small, and wear and the like do not occur, and a smooth steering operation can be performed.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the configuration of an embodiment of the present invention will be described for the case of a tractor as a traveling vehicle shown in the accompanying drawings. Figure 1 is a front view of the front wheel and front axle case, Figure 2
Is a side view, FIG. 3 is a schematic front view showing a link configuration of a steering drive unit, and FIG. 4 is a schematic plan view of the same.

In FIG. 1 and FIG. 2, the front axle case 1 is divided into three parts,
It is composed of a left axle case 1L and a right axle case 1R protruding to both sides. The center case 1M
Are fixed by bolts 6. The front axle case 1 is supported so as to be able to swing left and right with respect to an axle frame 2 constituting an airframe, and a pivot pin is formed at a central front end of a center case 1M. The center case 1M is rotatably supported, and the rear portion of the center case 1M is rotatably supported by a bracket 4 hanging down from the axle frame 2.

In the center case 1M, a steering cylinder 10 for power steering is provided horizontally in the horizontal direction, and the steering cylinder 10 is a double-rod double-acting cylinder with piston rods 10a projecting to both sides. It is composed of At the tip of the piston rod 10a, a spherical joint 11
The other end of the tie rod 12 is connected to the knuckle arm 13 via the tie rod 12.

The other side of the knuckle arms 13 is fixed to a wheel support portion 14 of the front wheels 9.9, and the wheel support portion 14 is supported by a rotating case 20 so as to be rotatable left and right. The wheel supporting portion 14 rotatably supports a wheel mounting portion 15 connected to an axle. The wheel mounting portion 15 is driven by a transmission shaft in the front axle case 1 through a king pin 16 vertically supported in a rotating case 20 and a gear, so that the front wheel 9 can be rotationally driven. The wheel support 14 is
The steering cylinder 10
Are slid left and right to form a spherical joint 11 and a tie rod 1.
2. The front wheels 9.9 can be turned left and right through the knuckle arm 13 to steer.

[0010] In these steering drive units, generally, wheel alignment can be performed smoothly so that steering operation can be performed, and traveling during straight running and turning is stabilized. The wheel alignment includes four elements of a toe-in, a camber, a caster, and a kingpin angle. In the present invention, the wheel alignment is set to an appropriate value range, and further, the caster is closely related to the piston rod 10a. The king pin angle and the knuckle arm angle are set so that the load applied to the piston rod 10a of the steering cylinder during turning is reduced.

That is, a king pin angle β (FIG. 1, FIG. 1), which is an inclination between a vertical line of the front wheel 9 and a caster angle α (FIG. 2) which is an attachment angle of the king pin 16 and a vertical line standing on an extension of the king pin 16. 3) configured to substantially the same angle
ing. Also, as shown in the schematic front view of FIG.
When moving forward, smell when piston rod 10a is L2
Then, the tie rod 12 is fixed to the piston lock in a front view.
And is positioned so as to be substantially in line with the
You. Similarly, in the schematic front view of FIG. 3 , the caster and the king pin are arranged such that the trajectory of the tie rod end 12a on the side where the piston rod 10a extends (when the length is L1) is substantially parallel to the steering cylinder 10 during turning. The angle and the knuckle arm angle γ (FIG. 4) are set.

In such a configuration, by sliding the steering cylinder 10, the piston rod 10a
When extending and turning from the length L2 when traveling straight, the piston rod 10a and the tie rod 12 are viewed from the front in FIG.
In the schematic front view of FIG.
(FIG. 3) is small, and the component force of the reaction force from the front wheel 9 in the direction perpendicular to the piston rod 10a is extremely small. Conversely, the reduced side (length L3) of the piston rod 10a is in the pulling direction and the length is short, so that the component force in the direction perpendicular to the tie rod 12 is small, and the abrasion does not increase.

[0013]

The present invention relates to a tractor front axle.
Case 1 with double rod type steering cylinder 10
The steering cylinder 10 is mounted horizontally in the horizontal direction.
At both ends of the stone rod 10a, tie rods 12
Arm connected to knuckle arm 13 via, steering the front wheels
The front view of the straight running state of the tractor in a configuration that allows it
The tap on the extension side when the piston rod 10a is slid
The rod 12 is substantially aligned with the piston rod 10a.
End trajectory of the tie rod 12 on the extension side
To be substantially parallel to the direction of the piston rod 10a.
Furthermore, the kingpin angle β and the caster angle α are substantially the same angle.
The following effects are obtained because the degree is set as the degree. First
In addition, when turning, the trajectory of the tie rod or the like on the side with a large amount of operation (the side protruding greatly inside the turn) is substantially parallel to the piston rod 10a when viewed from the front, so that the rotational force (torque) generated on both tie rods ) Out of
And vertical force and vertical force
The piston rod on the side that protrudes greatly in the force in the bending direction
To reduce or eliminate the rotating power of the pad 10a
As a result , loosening of each connecting screw portion can be prevented, and safety and reliability are improved. Second, the steering cylinder 10
On the extension side, the piston rod 10a and the steering
The angle of intersection with the
Component acting in the direction
The component force in the bending direction used is minimal, and the piston rod
Bending is prevented, and strength and safety can be improved.

[Brief description of the drawings]

FIG. 1 is a front view of a front wheel and a front axle case.

FIG. 2 is a side view of the same.

FIG. 3 is a schematic front view showing a link configuration of a steering drive unit.

FIG. 4 is also a schematic plan view.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Front axle case 10 Steering cylinder 10a Piston rod 12 Tie rod 13 Knuckle arm 16 King pin

──────────────────────────────────────────────────の Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B62D 5/10-5/16 B62D 5/26 B62D 7/08-7/12 B62D 7/16-7 / 20

Claims (1)

(57) [Claims] 1. A tractor front axle case 1
Double steering rod cylinder 10
The piston lock of the steering cylinder 10
At both ends of the door 10a, nuts are attached via tie rods 12.
Connected with the wheel arm 13 to make the front wheel steerable
In the configuration, when the tractor is
Tie rod 1 on the extension side when sliding rod 10a
2 is substantially straight with the piston rod 10a;
The end trajectory of the tie rod 12 on the extension side
It is configured to be substantially parallel to the direction of the rod 10a.
A tractor steering apparatus characterized in that the pin angle β and the caster angle α are substantially the same .