JPH085399B2 - Steering device for agricultural tractor - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a front wheel steering device for a tractor, and more particularly to a front wheel turning angle regulating device.

[0002]

2. Description of the Related Art Conventionally, stopper devices for limiting the cutting angle of front wheels of agricultural tractors have been disclosed in Japanese Patent Laid-Open No. 52-49532, Japanese Utility Model Laid-Open No. 59-100671, and US Pat.
Gears such as the one disclosed in Japanese Patent No. 191708 were known. However, in the case of the prior art, the left and right corner angle restriction stopper portions are arranged in the same manner. Therefore, when steering normally, if the left tire contacts the stopper at the rear of the kingpin when the front wheel is turned to one side for steering, the tire on the right also becomes the stopper just at the front of the kingpin. There is no problem in dealing with them. However, if the tire touches an obstacle while turning the steering wheel fully and turning, the tire is pushed and the steering wheel part is slightly returned and turned. When the tie rod is being operated, the impact cannot be transmitted by transmitting the impact up to the turning of the steering wheel. That is, since the hydraulic cylinder is fixed, it is necessary to receive this impact at the tie rod portion. In this case, the tie rod is strong in the force in the pulling direction, but weak in the force in the compressing direction and is easily broken. In the present invention, when such a situation occurs, a clearance t that allows rotation in the pulling direction is provided so as to be positively impacted by the force in the pulling direction.
In the past, most of them were constructed in the same way so that the pull and the stopper in the compression direction would come into contact with each other, and the gap was not taken into consideration.Therefore, the impact acts in the compression direction, bending the tie rod, and pivoting the joint. It was sheared.

[0003]

SUMMARY OF THE INVENTION The object of the present invention is to eliminate the disadvantages of the prior art. When the handle is fully cut on level ground, the stopper on the rear side of the kingpin should come into contact first, and the stopper on the front side of the opposite side of the kingpin of the tire on the opposite side. When a tire rides on an obstacle with a slight clearance left and the cutting angle is further increased, by absorbing at this clearance t,
It is designed so that no force is applied to the tie rods in the compression direction.

[0004]

The object of the present invention is as described above, and the structure for achieving the object will be described. That is, a power steering mechanism that rotates the bell crank by expanding and contracting the hydraulic cylinder device and rotates the front wheels through the tie rods by rotating the bell crank is provided with fixed gear boxes fixed at the left and right ends of the front axle. , A king pin is obliquely provided on the fixed gear box, and a turning gear box supporting a tire bearing is made rotatable about the king pin, and a tire turning angle is provided between the fixed gear box and the turning gear box. In the configuration provided with the stopper portion for restricting, a stopper portion is provided in front of and behind the kingpin for each of the left and right tires, and when the tractor turns, the stopper portion of the tire inside the turning diameter and the outside A stopper part that is configured as a two-step stopper of the tire stopper part and acts in the same direction on the left and right tires. , The left and right kingpins and the front left and right of the other kingpin, and when the left and right one of the stopper parts on the rear side of the kingpin are in contact, the left and right of the other kingpin In addition, a gap t is always formed in the front stopper portion.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The purpose and construction of the present invention are as described above, and the construction and operation of the invention shown in the accompanying drawings will be described. FIG. 1 is an overall plan view of a front wheel steering apparatus of the present invention, FIG. 2 is a front sectional view of a fixed gear box around a front axle and a king pin, a rotary gear box, and FIG. 3 is a side view of a front differential device section. FIG. 5 is a side sectional view showing a connecting portion of a driving intermediate shaft, and FIG. 5 is a plan view of a fixed gear box and a rotation restricting portion of a rotating gear box, which show an essential part of the present invention.

First, FIG. 1 will be described. E is the engine located in the hood of the agricultural tractor
A front axle bracket 7 is connected to the front of the. A hydraulic pump 19 is fixedly installed in the engine E, and hydraulic oil in a hydraulic oil tank 18 enters a steering cylinder 16 from a steering valve 21 below a steering handle via a safety valve 20.
The bell crank 17 is rotated by the steering cylinder 16 so that the left and right tie rods 9L and 9R receive a force in the tension and compression direction. 4L and 4R are knuckle arms, which are fixed to the upper part of the rotary gearbox 2 which rotates around the kingpin.
It rotates about the center of 2. 8L and 8R are tires that form the left and right front wheels. The rotation angle restriction stopper portion, which is a main portion of the present invention, may be anywhere on the tire and the front axle 5 side, but in the present embodiment,
It is configured as shown in FIG. 5 between the contact surface on the inner side of the rotary gearbox 2 and on the outer side of the fixed gearbox 1.

2 and 3, the rotation transmitted from the front pinion shaft 22 corresponds to the front differential device D shown in FIG.
Is transmitted to. Friction disk plates for a slipping clutch device are provided on the left and right sides of the front differential device D. Power is fixed by the differential side gear 5a inside the front axle 5 and the bevel gear 10 inside the gearbox 1 is fixed.
Is transmitted to. Bevel gear 1 in fixed gearbox 1
0 and bevel gear 11 mesh with each other, and king pin 12
The rotation is transmitted to the bevel gear 13. Bevel gear 1
3, a bevel gear 14 having a diameter larger than 3, an axle 15, a tire 8
The rotational force is transmitted to.

The rotary gear box 2 has a knuckle arm 4 fixed on the upper side thereof, and the upper and lower sides of the rotary gear box 2 are pivotally supported around a king pin 12 and are rotatable for steering. Reference numeral 3 also serves as a lid of the fixed gear box 1 and a pivot shaft of the knuckle arm 4. The stopper part of the rotation angle regulation, which is the main part of the present invention,
The outer surface of the fixed gear box and the inner surface of the rotating gear box are projected.

Reference numerals 6L and 6R are vertical stoppers for restricting the vertical swing angle of the front axle 5, which are also provided with lock nuts and bolts. The corners are also adjustable.
When the turning radius is reduced during traveling, the swing angle can be reduced and the tire cutting angle can be increased. Also, increase the swing angle during deep plowing work and loader work,
It is configured so that it can cope with the swing of the aircraft. Further, even if the front axle mounting center position is changed with respect to the vehicle body, the swing angle of the front axle can be freely selected by moving the bolt in and out.

FIG. 3 is a drawing showing the drive system from the mission case of the agricultural tractor to the front pinion shaft 22. The power take-off shaft 27 projects from the mission case, and the power is transmitted to the front pinion shaft 22 by the drive center shaft 24 composed of the cylinder shaft and the connecting bodies 23, 23.
Reference numeral 26 denotes a coupling, and the ball 25 fitted in the spline of the inner diameter is also fitted in the spline of the connecting body 23 to transmit power.

FIG. 4 is a view showing the other side of the connecting portion between the connecting body 23 and the power take-off shaft 27 'or the front pinion shaft. In this configuration, the connecting body 23 has a two-stepped structure, and the pins 28 are inserted and connected. 29 is pin 28
It is a ring that prevents the slip-out. With this configuration, when an overload is applied, it can be sheared like a shear pin, and it is easy to find and repair an accident. Also, the cost of conversion parts is small. In the past, when a bucket was loaded with earth and sand by a front loader operation to climb a slope, a gear or shaft, etc. was broken.

FIG. 5 is a plan view of the stopper portions 30L and 31L for restricting the rotation angle between the fixed gear box 1 and the rotary gear box 2, showing the essential part of the present invention. The direction of the arrow is the forward direction of the agricultural tractor, the side 31L is the stopper portion on the front side of the front axle, and the side 30L is the stopper portion on the rear side of the front axle. What is symmetrical to this is also provided on the right side of the front axle, and serves as stopper portions 30R and 31R. And the rotation angle regulation stopper portions 30L, 30R, 3
For 1L and 31R, the amount of protrusion can be adjusted by combining a bolt and a lock nut. It is also adjusted in relation to the swing angle regulation stoppers 6L and 6R of the front axle 5 shown in FIG.

In the position of the rotary gearbox 2'of FIG. 5,
The agricultural tractor is turning to the left in the traveling direction, and in this case, the left rotating gear box 2L is brought into contact with the rear stopper portion 30L. The right rotary gear box 2R (not shown) stops with a gap t immediately before it comes into contact with the front stopper portion 31L. Conventionally, in this case, the right rotary gear box 2
Since R has been in contact with the front stopper portion 31R, the contact portion of the right stopper portion 31R and the right tie rod 9R form a framework, and the bell crank 17 of FIG. 1 has a steering handle. Since it is fixed from the side, the tie rod 9R cannot return, and when the front axle contacts an obstacle and the front of the tire is pushed inward, the front of the tire cannot move with the stopper 31R, so the direction in which the tie rod is compressed. The tie rod was bent, and the pin of the pivotal support with the knuckle arm was sheared due to the force applied to. According to the present invention, even when an obstacle hits the front of the tire on the outside of the turning circle in this manner, the tie rod 9 is prevented from being immediately subjected to the compressive force, that is, the tire rotates inward, and the tie rod does not move. A gap t is provided in the stopper 31 so that a tensile force acts.

[0014]

Since the present invention is configured as described above, it has the following effects. Firstly, when the tractor turns, if there is only one stopper portion in one direction, it is troublesome when the stopper is damaged. Especially, in the power steering by hydraulic pressure, a large force acts on the stopper portion. Therefore, the present invention provides a two-step stopper portion. Therefore, even if one of the stopper portions is damaged, the other stopper portion plays the role. The positional relationship between the two-step stopper portions is such that the stopper portion of the tire on the inside in the turning direction hits first. When the stopper portion of the inner tire is damaged, the stopper portions of the other outer tires come into contact with each other. That is,
Since the stopper of the inner tire and the stopper of the outer tire of the turning diameter are configured in two steps, even if the stopper of the inner tire is damaged, the stopper of the outer tire is Therefore, the stopper portion can be made stronger and safer.

Secondly, in the case of a power steering device which steers by operating a tie rod with a hydraulic cylinder, a bell crank for moving the tie rod is used when an operator turns the steering handle to the full turning position. With a full shock, the safety valve does not open and the position is fixed and cannot return with a slight shock. Therefore, when an obstacle touches the front part of the tire while turning it with the handle fully turned, the movement of the tire was mechanically transmitted to the steering handle in the past, so the steering handle was forced. However, the power steering system can no longer perform the action of releasing the compressive force applied to the tie rods by returning to. Therefore, in the case of power steering, the bell crank 17
If a large force is applied between the knuckle arm and the tie rod in the direction of pushing the tie rod, and the safety valve does not open, the tie rod portion will be destroyed. In the present invention, in this case as well, the tie rod is provided with a gap t at which the tire 8 can slightly rotate forward inward so that a pulling force acts, not a compressive force, at the stopper portion. The shock of can be escaped in this gap t. In the past, when the steering wheel was fully turned, both the left and right tires contacted the stopper at either the front or rear. Therefore, if the tie rod is not adjusted correctly, the stopper part in the direction to receive the compressive force first comes into contact with the tie rod, and a gap occurs in the stopper part in the direction to receive the tensile force on the tie rod. When it collides with the side, the tie rod is compressed on the outside of the turning radius, and the tie rod is deformed or destroyed due to the force in the compression direction toward the bell crank where the tie rod cannot move. . According to the present invention, the stopper portion in the direction in which the tie rod pulls the tire, that is, the stopper portion of the tire inside the turning diameter is brought into contact with first, and the tie rod pushes the tire, and the stopper portion in which the force in the direction of compressing the tie rod is applied, that is, The gap t is positively provided in the stopper portion outside the turning diameter to eliminate this problem. That is, when an obstacle is generated in front of the tire outside the turning radius, the impact force is applied in the direction in which the tire is further steered and turned inward. Since the tensile force acts on the tie rod 9 rather than the compressive force, the tie rod 9 has durability against the tensile force, so that bending or breakage does not occur.

[Brief description of drawings]

FIG. 1 is an overall plan view of a front wheel steering system of the present invention.

FIG. 2 is a front sectional view of a fixed gear box and a rotating gear box around a front axle and a king pin.

FIG. 3 is a side view of a front differential device portion.

FIG. 4 is a side sectional view showing a connecting portion of a driving intermediate shaft.

FIG. 5 is a plan view of a fixed gear box and a rotation restricting portion of the rotation gear box, which show a main part of the present invention.

[Explanation of symbols]

1 Fixed gear box 2 Rotating gear box 5 Front axle 30L, 30R Rotation angle regulation stopper on the front side of front axle 31L, 31R Rotation angle regulation stopper on the front side of front axle

Claims (1)

[Claims] 1. A power steering mechanism for rotating a bell crank by expanding and contracting a hydraulic cylinder device, and rotating a front wheel through a tie rod by the rotation of the bell crank, and fixed gear boxes at left and right ends of a front axle. It is fixedly installed, the king pin is obliquely installed on the fixed gear box, and the rotating gear box supporting the bearing of the tire is rotatable about the king pin, and the tire rotation is provided between the fixed gear box and the rotating gear box. In a configuration in which a stopper portion that regulates a moving angle is provided, a stopper portion is provided in front of and behind the kingpin for each of the left and right tires, and the stopper portion is
At the time of turning of the tractor, it is configured to be a two-step stopper of the tire inside the turning diameter and the stopper of the outside tire, and the stopper that acts in the same direction on the left and right tires, It is placed on the rear side of one of the left and right kingpins and on the front side of the other left and right kingpins, and when one of the left and right stopper parts on the rear side of the kingpin is abutting, A steering device for an agricultural tractor characterized in that a gap t is always formed in the front stopper portion.