JPH0442227B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a steering control device for a four-wheel steering type tractor.

(Prior technology) The same type of work equipment is installed at the front and rear of the tractor body so that they can be raised and lowered, and the four wheels on the front, rear, left and right sides can be steered using a club steering method, etc. In the field, the work equipment on the front side in the direction of movement is lowered. A device in which work is performed while steering the four wheels is proposed in Japanese Patent Application No. 60-238958 (Japanese Unexamined Patent Publication No. 62-99268).

(Problem to be solved by the invention) Four-wheel steering, especially the club steering system, when combined with forward and backward movement, eliminates the need for turning at the edge of the field at all, significantly improving work efficiency; however, when driving on the road, It is necessary to change to the normal steering method, and if you forget to change it, there is a risk of an unexpected accident.

(Means for Solving the Problems) The present invention solves these problems, and as a means for that purpose, similar working machines are provided at the front and rear of the tractor body so that they can be raised and lowered, and the four working machines are installed at the front, rear, left and right sides. In a four-wheel steering type tractor whose wheels can be freely steered, there is a detecting means for detecting that both the front and rear working machines are raised and an operator is seated on a seat, and a detecting means for detecting that an operator is seated on a seat, and a mechanism for moving the rear wheels straight when the detecting means detects The vehicle is equipped with a return means for returning the vehicle to its position, and a restraint means for restraining the rear wheels, which have been returned to the straight-ahead position by the return means, from being steerable.

(Function) When performing work, an operator does not sit on the seat 24, and the automatic control device is activated by remote control such as a radio from outside to perform the following operations.

When carrying out work by moving the tractor 1 forward, the front working machine 27 is lifted up, the clutch 41 is disengaged and it is kept stationary, and the rear working machine 28 is held stationary.
The chisel is lowered onto the ground, the clutch 40 is brought into contact, and the tilling section 28B is rotated to till the soil.

At this time, the clutch 37 is connected and the pair of left and right front wheels 2 are driven in the forward direction, and the front working machine 2
7 is lifted, its weight is added to the front wheels 2, and a large traction force can be obtained.

Furthermore, since the lug 2A of the front wheel 2 rotates in the direction of discharging (jumping) soil while holding it in, soil adhesion is reduced and a large traction force is obtained.

When the work progresses and the tractor 1 reaches the headland, it is necessary to move on to the next work process, but at this time, both the front work equipment 27 and the rear work equipment 28 are lifted up, and the front wheels 2 and rear wheels 3 are The tractor 1 moves in the same direction by moving the tractor 1 backwards using a club steering method. For example, when the steering command device 42 issues a right steering command, the right solenoids 47 and 48 of the electromagnetic valves 43 and 44 are energized, and the steering cylinder 1
Pistons 8 and 19 move to the left, and the front wheels 2 and rear wheels 3 are steered to the right around the king pin via the knuckle arms 15 and 16 as shown by the imaginary line in FIG.

When the movement to the next work process is completed, the front work machine 27 is lowered to the ground, the rear work machine 28 is lifted up,
Work is carried out by moving the tractor 1 backwards while driving only the front working machine 27. At this time, the rear wheels 3 are driven.

When driving on the road, the operator sits on the seat 24 and lifts the front and rear working machines 27 and 28, and manually steers the front wheels 2 using the steering handle 23 while driving the rear wheels 3 in a straight line. Lock it in the driving position.

That is, when the operator sits on the seat 24, the seating detector 50 is activated, and the front and rear working machines 27, 28 are activated.
When both rise, the rise detector 49 is activated. As a result, the switch element 5
2 and 53 are turned off, the signal from the steering command device 42 is cut off, and the return means 54 is activated. That is,
If the rear wheel 3 is now located at the position of the virtual line in FIG. 2, the turning angle detector 55 detects it and inputs a detection signal to the comparator 57. Then, the comparator 57 compares the neutral signal and the detection signal, and the comparison value is sent to the discriminator 5.
8, the discriminator 58 discriminates the return direction, drives either the left or right solenoid 46, 48, and puts the rear wheel 3 in neutral by operating the solenoid valve 44 and steering cylinder 19. Return to the straight-ahead position. At the time of the virtual line in FIG. 2, the left solenoid 46 of the electromagnetic valve 44 is energized to move the rear wheel 3 to the left. When the rear wheel 3 returns to the straight-ahead position, the comparison value becomes zero and the switch elements 52 and 53 of the restraining means are both turned off, so the solenoid valve 44 locks the steering cylinder 19 in the neutral position. Therefore, like a normal vehicle,
You can drive by steering only the front wheels 2.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

1 to 4, reference numeral 1 denotes a tractor, which is equipped with a two-axle, four-wheel type traveling device 4 consisting of a pair of left and right front wheels 2 and a pair of left and right rear wheels 3.

Reference numeral 5 denotes a mounted engine, which is mounted on the front side of the tractor body 6 and covered by a bonnet 7.

The rotational power of the engine 5 is transmitted to the first transmission section 9 through the connection and disconnection of the main clutch 8.
The transmission can be transmitted to a second transmission section 14 having a traveling system transmission section 12 and a PTO transmission section 13 via the propeller shafts 10 and 11, respectively.

Both the front wheels 2 and the rear wheels 3 have lugs 2A and 3A, and both lugs 2A and 3A have a diagonal lug pattern, and as shown in FIG. 3, the lugs 2A hold the soil when driven forward. The lug 3A is a pattern that exerts traction force by holding in and discharging soil when the vehicle is driven in reverse, and the directions of the lugs 2A and 3A are reversed. There is.

Both the front wheel 2 and the rear wheel 3 have the same diameter, and both are provided at both ends of the axle so that they can rotate freely around the kingpin axis, and have knuckle arms 15 and 16 on the left and right kingpin axis sides, respectively. The left and right knuckle arms 15, 16 are connected to tie rods 20, 2 having steering cylinders 18, 19.
They are connected by 1. In addition, each cylinder 18, 1
9 is said to be double acting.

Reference numeral 22 denotes a steering device, which includes at least a steering handle 23 and a driver's seat 24, which are provided on the tractor body 6 at a distance from the front and rear, and also includes various clutch operating levers and working equipment, although not shown. It is equipped with various levers such as a hydraulic control lever for lifting and lowering, and a gear shift lever.

The steering handle 23 controls the steering cylinders 18 and 19, respectively, and has a control section 25 as schematically shown in FIG. 3 to enable power steering.

Both the front wheels 2 and the rear wheels 3 can be independently steered around the kingpin (including straight forward movement), and both the front wheels 2 and the rear wheels 3 can be turned in the same direction as shown by the chain lines in Fig. 2. It constitutes a clutch steering system that moves forward and backward diagonally.

27 is a front working machine, 28 is a rear working machine,
In this example, both are the same type of working machines exemplified as rotary tillers, and both have a power receiving shaft 27.
A, 28A, and the tilling parts 27B, 28B can be driven from the tractor PTO shaft.

In addition, it is desirable that each of the tilling parts 27B and 28B can be freely switched between forward and reverse directions.

The front and rear working machines 27 and 28 are mounted on the tractor body 6 in this example by mounting mechanisms 29 and 30 with two-point links so that they can be raised and lowered, and the front working machines 2
7 is raised and lowered by a lift cylinder 31, and the rear working machine 28 is raised and lowered by a lift arm 32.

The first transmission section 9 and the second transmission section 14 are provided with a forward/reverse switching mechanism to enable the tractor 1 to move forward or backward, and the traveling system transmission section 12 is connected to the rear end differential mechanism 33.
35 is a propeller shaft for driving the front wheels.

Clutches 36 and 37 are provided on the route to the rear wheel differential mechanism 33 and on the route to the front wheel differential mechanism 34, respectively.
7 can be freely connected and disconnected, and it is possible to drive either one of the front and rear wheels 2 and 3 or to drive both the front and rear wheels 2 and 3.

The PTO transmission section 13 is equipped with a rear PTO transmission section 38 and a front PTO transmission section 39 as output sides, and clutches 40 and 41 are provided on each output side, and the transmission section 38 rotates at the same speed. , 39 can be freely connected and disconnected.

FIG. 5 shows the control section 25 of the steering cylinders 18 and 19.
, and 42 is a steering command device such as a potentiometer that is linked to the steering handle 23 and generates signals for left steering and right steering. 43 and 44 are steering cylinders 1
Solenoid valve for 8, 19, left solenoid 45, 4
6 and right solenoids 47 and 48, each of which is driven by a left steering signal and a right steering signal. Reference numeral 49 is a rise detector that detects the rise of the front and rear working machines 27 and 28, and 50 is a seating detector that detects that the operator is seated on the seat 24. A gate circuit 51 constitutes a detection means together with the detectors 49 and 50, and generates a signal for restraining the rear wheels in neutral when the detectors 49 and 50 work together. Reference numerals 52 and 53 designate switch elements that cut off the signal from the steering command device 42 when a restraint signal is received. 5
4 is a return means, which includes a steering angle detector 55 for the rear wheel 3;
A straight-line position signal generator 56, a comparator 57 that compares the signals from the detector 55 and the generator 56, and a discriminator 58 that determines the straight-line return direction of the rear wheel 3 from the comparison value and drives the solenoids 46 and 48. It consists of
It is designed to work when a restraint signal is received.

The solenoid valve 44 and the switch elements 52 and 53 constitute a restraining means for restraining the rear wheel 3 in a straight-ahead position so that it cannot be steered.

(Effects of the Invention) According to the present invention, there is provided a detection means for detecting that both the front and rear work machines have risen and an operator is seated on the seat, and a detection means for returning the rear wheels to the straight-ahead position upon detection by the detection means. and a restraining means for restraining the rear wheels returned to the straight-ahead position by the returning means so that the rear wheels cannot be steered. Although it is a steering type vehicle, it can be driven by steering only the front wheels, so the steering operation when driving on the road is similar to that of a normal vehicle, making it easy to drive. In addition, if the detection means detects rising or seating, the return means returns the rear wheels to the straight-ahead position, so the rear wheels are not restrained in a position other than the straight-ahead position, and moreover, the rear wheels can be returned to the straight-ahead position by manual operation. No need to undo. Therefore, the operator can sit on the seat, raise the front and rear working machines, and then move on to driving on the road without any problems in operation.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is an overall side view, FIG. 2 is a plan view thereof, FIG. 3 is a schematic plan view showing the steering system, and FIG. 4 is a schematic plan view showing the transmission system. ,
FIG. 5 is a block diagram showing the control system. 2, 3...front wheel/rear wheel, 2A, 3A...lug,
4... Two-axle four-wheel traveling device, 6... Tractor body, 18, 19... Steering cylinder, 23... Steering handle, 27, 28... Working machine, 43, 44...
... Solenoid valve, 49 ... Climb detector, 50 ... Seating detector, 54 ... Return means.

Claims (1)

[Claims] 1. In a four-wheel steering type tractor, in which the same type of work equipment is installed at the front and rear of the tractor body so that they can be raised and lowered, and the four wheels on the front, rear, left, and right sides can be freely steered, the front and rear work equipment can be raised together, and an operator is seated in the seat. a detecting means for detecting that the vehicle is in the straight-ahead position; a returning means for returning the rear wheels to the straight-ahead position when detected by the detecting means; and a restraining means for restraining the rear wheels returned to the straight-ahead position by the returning means so that they cannot be steered. A steering control device for a four-wheel steering type tractor, characterized by comprising: