JPH06286640A - Steering controller for tractor - Google Patents

Abstract

PURPOSE:To facilitate the speedy selection of the steering control mode between the FWS, RWS, 4WS, etc., of a tractor speedily. CONSTITUTION:A steering controller 9 is equipped with the front and rear wheel steering hydraulic circuits 4 and 8, and carries out steering control so that the wheel on the side fixed at a neutral position follows to the wheel on the steered side, in the selection to 4WS through the front/rear wheel steering, while in the selection to FWS or RWS, the controller 9 performs control so that the wheel on the fixed side is controlled so as to automatically return to the neutral position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steering control device for a tractor.

[0002]

2. Description of the Related Art In tractor work, it is required to perform appropriate traveling while selecting various steering modes depending on the field conditions. Generally, in the straight travel range, the FWS steering mode is set by steering only the front wheels, and in the turning process, the 4WS steering mode is set by steering the front wheels and the rear wheels. obtain.

However, such FWS, 4W
In switching between steering modes such as S and RWS by steering only the rear wheels, both the front and rear wheels are temporarily returned to the neutral position, and then the steering wheels are steered. Is normal. For example, in a mode in which the steering cylinder for the front wheels and the steering cylinder for the rear wheels are hydraulically actuated by a single steering control valve in a fixed relationship, reverse steering operation is performed or the sloping ground is moved in the contour line direction. When working while traveling, it is not possible to configure, or it is complicated if possible.

According to the present invention, there is provided a front wheel steering hydraulic circuit having a front wheel steering cylinder for steering front wheels and a steering control valve, and a rear wheel steering cylinder having a rear wheel steering cylinder for steering rear wheels and a steering control valve. By providing the wheel steering hydraulic circuit, by independently controlling both steering control valves, it is possible to promptly and smoothly switch between the steering modes.

[0005]

The present invention is directed to a front wheel steering hydraulic circuit 4 having a front wheel steering cylinder 2 for steering a front wheel 1 and a steering control valve 3, and a rear wheel for steering a rear wheel 5. Rear wheel steering hydraulic circuit 8 having steering cylinder 6 and steering control valve 7
And when switching to 4WS by steering the front and rear wheels,
The wheel on the side that has been fixed until now follows the wheel on the steered side, and when switching to FWS for front wheel steering or RWS for rear wheel steering, the wheel on the side to be fixed is automatically moved to the neutral position. The steering control device for a tractor is provided with a steering control device 9 for controlling the steering to return.

[0006]

In the front wheel steering hydraulic circuit 4, the front wheel steering control valve 3 is actuated by the output from the steering control device 9, the front wheel steering cylinder 2 is expanded and contracted, and the front wheel 1 is operated.
Is steered. Further, in the rear wheel steering hydraulic circuit 8, the rear wheel steering control valve 7 is actuated by the output from the steering control device 9, the rear wheel steering cylinder 6 is expanded and contracted, and the rear wheels 5
Is steered.

The steering mode, which is a steering control mode, is the FWS.
Switching control among the mode, the RWS mode, and the 4WS mode is performed. For example, when the FWS mode is switched to the 4WS mode, it is assumed that the steering angle of the front wheels 1 and the steering angle of the rear wheels 5 are controlled to be equal in opposite phases by the output from the steering control device 9. For example, in this steering mode switching state, the rear wheels 5 are in the neutral position in the straight-ahead state, so that the rear wheels 5 are in the same steering direction in opposite phase to the front wheels 1 steered by the steering wheel.
Steering control is performed.

When the FWS mode is switched to the RWS mode, the front wheels 1 are returned to the neutral position, and the rear wheels 5 in the neutral position are steered to be switched by the steering wheel. . In this way, the front wheel 1 is controlled by the front wheel steering control valve 3 and the rear wheel 5 is controlled.
Are controlled by the rear wheel steering control valve 7 independently by the output from the steering control device 9,
The steering control by switching between the steering control modes such as the WS mode, the RWS mode, and the 4WS mode is easily and accurately performed, and the steering positions of the front wheels 1 and the rear wheels 5 before the steering mode switching. Therefore, it is possible to directly and quickly control the steering to each steering position after the steering mode is switched.

[0009]

1 to 5, a tractor is a front wheel 1
In the four-wheel drive mode in which the four wheels of the rear wheels 5 can be driven to travel, the steering wheel 11 in front of the cockpit 10 is operated to steer the front wheels 1 and the rear wheels 5. 1
Reference numeral 2 is a bonnet that covers the engine E mounted inside.
Reference numeral 13 is a lower link for connecting working machines at the rear of the vehicle body.

The front and rear wheel steering hydraulic circuits 4, 8 have hydraulic pumps P, and the steering cylinders 2, 2 for the front and rear wheels 1, 5 via the front and rear wheel steering control valves 3, 4. 6 is configured to extend and retract, and the front and rear wheel steering cylinders 2 and 6 of the piston 1
By moving in and out of the steering cylinders 2 and 6 of 4, 15
By the steering arms 16 and 17, the tie rods 18 and 19 and the like, the pair of left and right front and rear wheels 1 and 5 are connected to the king pins 20 and 2.
Turn around to steer.

The front wheel steering control valve 3 is composed of an electromagnetic valve. When the solenoid A is turned on, the front wheel steering cylinder 2 is contracted to steer to the left in the forward direction F, and the solenoid B is turned on.
Extend the cylinder 2 and steer to the right. Similarly, in the rear wheel steering control valve 7, when the solenoid C is turned on, the rear wheel steering cylinder 6 is contracted and steered to the left side, and when the solenoid D is turned on, the cylinder 6 is extended and steered to the right side.

The steering control device 9 has a rotary encoder 22 for detecting the operation angle of the steering wheel 11 and inputting it to a controller CPU having a microcomputer, and also for turning off the front wheels 1 and the rear wheels 5. It has potentiometers 23 and 24 for detecting the angle, and also has a steering mode switch 25 by which the FWS, 4 and
Steering output control is performed according to the steering mode such as WS and RWS. The steering mode switch 25 may be provided with, for example, a switch manually operated, but since it is automated according to the work, it detects an up / down movement of a lift arm that raises / lowers a working machine connected to the lower link 13 or the top link. It is advisable to input with a lift arm sensor, and further with a forward / reverse position switch, etc. by a reverser operation for switching the forward / backward movement of the tractor. (1) 4W for turning while working in FWS mode
In the case of switching to the S mode, if the setting is made so that the turning signal of the front wheel 1 proportional to the turning angle of the steering wheel 11 is output, the FWS mode of the steering mode switch 25 is switched to the 4WS mode. And the steering angle 22 is detected, the front wheels 1 are steered by the solenoid A or B. At the same time, the rear wheel 5 causes the front wheel 1 to move by the solenoid C or D.
It is steered to be in the opposite phase (equal angle) to and. In the FWS mode, the rear wheel 5 is fixed at the neutral position and is not steered in any direction, so the steering of the rear wheel 5 is performed from this neutral position. When the rear wheel 1 is steered to the left, the solenoid C is output so that the rear wheel 5 is steered from the neutral position to the right in the opposite phase. Therefore, even when the front wheel 1 is operated not only in the neutral position in the FWS mode but also from the right steering position to the left steering immediately, the rear wheel 5 does not turn to the left steering once but directly moves from the neutral position to the right steering. Operation is controlled. (2) The steering control by switching from the FWS mode to the 4WS mode is the same as the steering control when switching from the RWS mode to the 4WS mode. (3) In the case where the FWS mode is switched to the RWS mode to steer, the rear wheels 5 are in the neutral position in the FWS mode, but the front wheels 1 may already be steered. The front wheel 1 is corrected so that it is returned to the neutral position. The rear wheel 5 is steered according to the turning angle of the steering wheel 11.

At this time, when operating the tractor by backward high speed traveling, the steering may be performed in the RWS mode. At this time, the reverse mode is switched by the reverser operation or the like to switch to the RWS mode. Similar output steering control is performed. (4) The steering control by switching from the FWS mode to the RWS mode is the same when the 4WS mode is switched to the RWS mode. However, in the 4WS mode, the rear wheel 5 is often in the left and right steering positions other than the neutral position, and the output steering control is immediately performed from these positions to the position operated by the steering handle 11. (5) In many cases, switching from the 4WS mode to the FWS mode shifts from the end of turning steering to the work stroke of straight running, and the rear wheels 5 are returned to the neutral position because they are being steered in the turning direction. The front wheel 1 is steering-controlled from the steering position in the turning direction to the steering position by the steering handle 11 after the mode switching. (6) When the RWS mode is switched to the FWS mode, steering control is similarly performed.

In FIGS. 4 to 6, the lower link 13 is rotatably supported by the final case 27, which is rotatably provided at both left and right ends of the rear axle housing 26. Reference numeral 28 is a 2P hitch located above the left and right lower links 13. In FIG.
The difference from the above example is that the front and rear wheel steering control valves 3 and 7 are replaced by front and rear wheel steering drive orbit rolls 29 and 30 and motors M1 and M2 that drive these orbit rolls 29 and 30. Are provided independently of each other, and the steering wheel 11 is operated to output the orbit rolls 29 and 30 according to the steering mode to control the steering of the front and rear wheel steering cylinders 2 and 6. To do.

8 to 10 are different from the above example in that
A rear-wheel steering cylinder 6 that steers the rear wheels 5 is provided with a double-acting correction cylinder 29, and by operating a control valve 31 of an independent hydraulic circuit 30, a steering operation position of the rear-wheel steering cylinder 6 is obtained. Is for fixing the steering position phase of the rear wheel 5 with respect to the steering position of the front wheel 1 in a fixed state. As in the case of working while traveling along a contour line on a slope, In the club steering mode in which the wheels 5 are steered in the same direction, the steering control can be facilitated by this correction.

A piston 32 is provided at the base of the rear wheel steering cylinder 6.
Is fixed, and the rear wheel 5 is steered by expanding and contracting by the hydraulic pressure of the correction cylinder 29. 32 is the car body, 3
Reference numeral 3 is a flow dividing valve, and 34 is a lift cylinder or the like. 11-
In FIG. 13, the difference from the above example is that in a tractor with a cabin 35 covering the cockpit 10, a tank 36 for controlling chemicals is attached to the rear part of the vehicle body 32, and the cylinder 36
Has a concave shape and is fitted and attached to the rear part of the vehicle body 32. The upper and lower surfaces 38 on both left and right sides of the concave portion for fitting the tank 36 to the vehicle body 32 are formed in the form of a fender 37. Follow. 39 is a door glass of the cabin.

[Brief description of drawings]

FIG. 1 is a steering control hydraulic circuit diagram.

FIG. 2 is a steering control block diagram.

FIG. 3 is a perspective view of a steering handle portion.

FIG. 4 is a plan view of the tractor.

FIG. 5 is a side view of the tractor.

FIG. 6 is a rear view of the tractor.

FIG. 7 is a steering control hydraulic circuit diagram using an orbit roll.

FIG. 8 is a hydraulic circuit diagram showing another embodiment.

FIG. 9 is a sectional view of the correction cylinder portion.

FIG. 10 is a plan view showing a steering mode configuration of the tractor.

FIG. 11 is a side view of the tractor to which the antifouling liquid tank is attached.

FIG. 12 is a front view thereof.

FIG. 13 is a plan view of the tank.

[Explanation of symbols]

 1 Front Wheel 2 Front Wheel Steering Cylinder 3 Steering Control Valve 4 Steering Hydraulic Circuit 5 Rear Wheel 6 Rear Wheel Steering Cylinder 7 Steering Control Valve 8 Steering Hydraulic Circuit 9 Steering Control Device

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuhiro Miyauchi, No. 1 Yakura, Tobe-cho, Iyo-gun, Ehime Prefecture, Engineering Department, Iseki Agricultural Machinery Co., Ltd. Department

Claims (1)

[Claims] 1. A front wheel steering cylinder 2 for steering a front wheel 1.
And a front wheel steering hydraulic circuit 4 having a steering control valve 3, a rear wheel steering cylinder 6 steering a rear wheel 5, and a rear wheel steering hydraulic circuit 8 having a steering control valve 7. When switching to 4WS by rear wheel steering, the wheel that has been fixed until now follows the wheel on the steering side, and when switching to FWS for front wheel steering or RWS for rear wheel steering, A steering control device for a tractor, which is provided with a steering control device 9 for performing steering control to automatically return the wheels to be fixed to a neutral position.