JPS6331883A - Steering control system for tractor or the like - Google Patents

Abstract

PURPOSE:To make accurate, safe steering control performable according to traveling soil conditions or working conditions and so on, by installing a braking ratio setting device which alters and sets the ratio of braking force of driving wheels to a steering angle of a steering wheel. CONSTITUTION:A car body is traveled with rotation of symmetrical driving wheels 3, but when its traveling direction is changed, a steering wheel 1 is steered and simulteneously these driving wheels 3 at the steering side is braked by brakes 10 at the time of sudden turning. At this time, a theoretical turning radius by steering wheels 2 is operated at a steering angle of the steering wheel 1 and also a theoretical turning radius by a speed difference between these symmetrical driving wheels 3 is operated, respectively. Braking force of these driving wheels 3 is worked so as to cause each radius ratio to be entered in a constant area. And, when soil conditions or working conditions is changed and the ratio of braking force to the steering angle and these driving wheels 3 is changed, operation of a braking ratio setting device 4 takes place. Thus, accurate and safe steering control is performable according to traveling soil conditions or working condition or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a control system for a tractor or the like and can also be used for a transport vehicle.

Conventional technology When operating a tractor, the front +1 wheels (steering wheels) are provided so that they can be freely steered by a steering handle, and the rear wheels (left and right driving wheels) are driven by a differential gear.
It is also equipped with left and right brakes that can brake the left and right drive wheels independently, and left and right brake pedals.

Problem to be Solved by the Invention In order to make a sharp turn by turning the steering wheel and simultaneously applying the brakes on the drive wheel 1j on the side of the change in direction, when changing the direction of the tractor, the turning force of the front wheels and the rear wheel drive are required. The ratio of turning force from the wheels varies depending on soil conditions, wheel conditions, front-to-back load ratio, etc. When working in the field, it is often necessary to make sharp turns, whereas when driving on the road, it is often necessary to make sharp turns. It is dangerous to overwork the brakes. This invention attempts to change and adjust the ratio of the braking force of the left and right rear drive wheel brakes to the front wheel steering angle (wheel steering angle) in accordance with each of these driving conditions.

Means for Solving the Problems This invention is based on the theoretical turning diameter of the steering wheels (2) steered by the steering handle (1) and the left and right drive wheels (3).
By comparing with the theoretical turning path due to the speed difference between (3,), the drive! In steering control that controls the braking force for the F/I ten wheels (3) to move, the ratio of the braking force of the driving wheels (3) to the steering angle of these steering wheels (2) is changed and set. This is a configuration of a maneuver control system for a tractor, etc., which is provided with a braking setting device (4).

Operation of the invention The power from the engine is transmitted to the left and right drive wheels (2) to drive the vehicle, but when changing the running direction, the steering wheel (1) is turned towards the running direction and the vehicle is turned sharply. At this time, the drive wheel (3) on the travel side is braked by stepping on the brake pedal. At this time, the theoretical turning radius of the steering wheel (2) is calculated based on the steering angle of the steering wheel (1), and the theoretical turning radius is calculated based on the speed difference between the left and right driving wheels (3) (3). The vehicle can be steered and turned by applying braking force to the left and right drive wheels (3) (3) so that the ratio of both theoretical turning radii falls within a predetermined range.

When making a sharp turn by increasing the steering angle of the steering wheel (1), the braking difference between the left and right drive/F wheels (3) (3) increases, and conversely, the steering wheel (1) When the turning radius is increased by decreasing the angle, automatic 'IJ1'H is performed so that the braking difference is decreased.

When changing the ratio between the steering angle of the steering wheels (2) and the braking force for the drive wheels (3) due to changes in soil conditions or work conditions, operate the braking ratio setting device 2t (4). By doing so, the braking force for the drive wheels (3) is adjusted to a preset range. For example, if the braking force is to be increased under soft soil conditions, the left and right drive wheels (3) are 3) The braking force for (3) becomes stronger, and the turning radius can be made smaller with respect to the steering angle of the steering handle (1). Also, when driving on the road, the left and right drive wheels (
3) By weakening the braking force for (3), the braking force becomes weaker with respect to the steering angle of the steering handle (1), thereby preventing sudden turns.

Effects of the invention As described above, the steering wheel (1) operated by the steering handle (1)
The braking force between the left and right drive wheels (3) (3) is adjusted depending on the steering angle (2), and the turning radius is automatically controlled to match the steering angle. ), the braking force for the drive wheel (3) changes y41! The automatic turning control is performed by changing the ratio of the braking force of the driving wheels (3) to the steering angle of the steering wheels (2), and the turning control is performed according to the soil conditions on which the vehicle is traveling, working conditions, etc. , accurate and safe steering control can be performed, and braking of the left and right drive wheels (3) during steering operation can also be performed by operating a single brake pedal.

Example 1 In addition, in Figure 1 and Figure 52, the tractor body (
5) has a front steering wheel (2) that is steered by operating the steering handle (1), and a differential transmission (7) is provided in the transmission 921 (6) transmitted by the engine. ,
It is configured to transmit power to the left and right rear drive wheels (3), and a brake disc (9 ) to j
The brake disc (9) is provided with a brake (10) which can be braked by hydraulic pressure.

The steering shaft (11) of the steering handle (1) is provided with a steering angle sensor (12) consisting of a potentiometer or the like that detects the steering angle.
) is provided with an arithmetic unit (13) comprising a microcomputer that calculates the theoretical turning radius of the steering wheel (2) by detecting the steering angle of the steering wheel (2).

The braking ratio setting device f'i (4) consists of a potentiometer etc. operated by a lever or dial operation, etc.
This correction calculation device (10) is provided with a correction calculation bag ff1 (14) that corrects the braking force to be applied to the brake (10) based on the theoretical turning radius calculated by the calculation bag M (13). The braking ratio that is corrected depends on the hardness and softness of the soil in the I+1 field, the depth and shallowness of the paddy field, the load ratio between the front and rear wheels of the tractor, and other factors.

The optimum braking force of the drive wheel (3) according to the steering angle of the steering wheel (2) is determined based on the standard range using experimental values, etc., and then various types of braking forces such as those mentioned above are applied at the steering site of tractor work. Select and set according to conditions.

Rotation sensors (+5) (15) for detecting the number of rotations are provided on each transmission shaft (8) (8) of the left and right drive wheels (3) (3), and the rotation speed is detected by these re-rotation sensors (15) (15). A calculation device (16) is provided that calculates a theoretical turning radius based on the ratio of rotational speeds.

The theoretical turning radius calculated by this calculation unit 21 (1B),
Correction calculation device! Comparison '5t22 (17) shows that the braking force of the brake (10) is maintained as it is when it is within the predetermined range, but the braking force of the brake (10) is maintained as it is depending on the steering angle. Theoretical turning radius is corrected by a calculation device! ! 1
(14), if the corrected turning radius is too large than the theoretical turning radius determined by the arithmetic circuit (1B), the control device 21 (18) controls the left and right brakes (10
) (10) The hydraulic valve (!9) is switched to reduce the braking difference between the brakes (10) and the hydraulic braking of the brake (10) is automatically controlled. In addition, the corrected turning radius is calculated by the calculation device (1
If the turning radius is too small than the theoretical turning radius based on θ), the hydraulic valve (19) is switched so as to increase the dynamic difference between the left and right brakes (10) (10). In this way, the steering is controlled based on the braking force and braking ratio of the left and right WJA wheels (3) (3) that are adapted to the running conditions according to the steering angle of the steering wheel (2).

Note that the calculations and controls in the correction calculation device (eye), the calculation device (is), the comparison device 21 (+7), the control device (18), etc. are performed by the calculation device! A microcomputer is used as in t(13).

The difference between the embodiment shown in FIG. 3 and the upper part is that the effectiveness of the brake (IQ) is changed depending on information such as the working condition and the driving condition, and a transmission device that changes the driving speed;
An information sensor (20) that detects the transmission of the power take-off shaft that transmits the work equipment, other means for regulating work, etc. is used to apply the braking force of the brake (lO) to match the intended work. So, this information sensor (20)
The correction value to be corrected is determined in advance according to the purpose of the work, etc., and the correction turning radius of the correction calculation unit ff1 (14) is calculated based on the detection by the information sensor (20). As a result, the rough braking force ratio can be determined from the driving information from this information sensor (20).

Adjustment of the narrow braking force ratio is controlled by a braking ratio setting device (4).

In the embodiment shown in FIG. A vehicle speed calculation unit m (21) is provided which calculates the vehicle speed from the rotational speed of the steering wheel (2 ) and the driving wheels (3
) to change and adjust the ratio to the steering force. It is determined that when the vehicle speed is faster than a predetermined range, the effectiveness of the brake (10) is reduced, and when the vehicle speed is slower than a predetermined range, the effectiveness of the brake (10) is increased.

[Brief explanation of the drawing]

The drawings show embodiments of the present invention; FIG. 1 is a partially cutaway plan view, and FIGS. 2 to 4 are block diagrams of each embodiment. In the figure, code (1) is a steering handle, (2) is a steering wheel,
(3) is the drive wheel, (4) is the braking ratio setting device 21. (
7) is the operating transmission device 21. (10) indicates a brake.

Claims (1)

[Claims] By comparing the theoretical turning radius of the steering wheels (2) steered by the steering handle (1) with the theoretical turning radius of the left and right driving wheels (3) based on the speed difference between the left and right driving wheels (3),
), a braking ratio setting device (
4) A control system for a tractor, etc.