JPH0417820B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a steering control device for a trailer, for example, for driving an agricultural work vehicle (hereinafter referred to as a trailer) towed by a tractor along a predetermined travel route. .

[Conventional technology]

As the steering control device for the above-mentioned trailer, for example, the present applicant has applied
There is No. 289472. The outline is shown in Fig. 5 and Fig. 6.

The tractor 100 has a traction rod 101 pivotally supported at the rear thereof so as to be swingable in the left and right directions, and a trailer 102 is connected to the tip of the traction rod 101. The towing rod 101 consists of a long main rod 103 and a short and small sub-rod 104, which are connected by a pin 105, and the tip of the main rod 103 is supported by the tractor 100, and the rear end of the sub-rod 104 is supported by the trailer 102. . 106
It is a cylinder for aligning the ridges, and the trailer 102
and the main rod 103.

The trailer 102 has wheels 107 and 108 on both sides.
Equipped with. The wheels 107 and 108 each have an L-shaped arm 1 pivotably supported on a vehicle body frame 110.
11 and 112, the other arm is connected by a connecting rod 113, and one arm 111 is equipped with a hydraulic cylinder 11.
4 and these L-shaped arms 111, 11
2. A steering mechanism 115 is constituted by the connecting rod 113 and the hydraulic cylinder 114.

Further, a hit angle detection sensor 120 is provided on the main rod 103 of the tractor 100.

Thus, the tractor 100 is caused to travel along the arc C by operating a steering operation mechanism (not shown). As a result, the axis 121 of the tractor 100 and the main rod 103 form an angle (hit angle) 122. This angle is detected by the hit angle detection sensor 120, converted into an electric signal, and a calculation circuit (not shown) operates the steering mechanism 115 to perform a swinging motion of the wheels 107, 108.
Transition along a predetermined travel route.

[Problem to be solved by the invention]

When the trailer 102 is an agricultural work vehicle, it is necessary to shift the trailer 102 eccentrically from the traveling axis of the tractor 100 in order to align the trailer. For this operation,
The ridge alignment hydraulic cylinder 106 is operated to form an angle α1 between the main rod 103 and the sub rod 104. This angle is equal to the hit angle α2 (hereinafter referred to as the ridge angle) when the tractor 100 and trailer 102 move straight.

Therefore, when the tractor 100 changes direction in this state, the trailer 10 is calculated by adding or subtracting from this angle α2.
It is necessary to operate the second steering mechanism 115.

In this case, the ridge alignment angle is not constant and needs to be changed. Therefore, when changing the direction of the tractor 100, it is necessary to always consider the undulation angle, which makes the operation complicated.

In view of this, an object of the present invention is to move a trailer following the direction change of a tractor without having to consider the ridge alignment angle.

[Means to solve the problem]

To achieve the above object, the present invention provides a trailer towed via a traction member attached to a drawbar of a tractor, in which the traction member includes a traction bar connecting the drawbar and a trailer front frame, and an auxiliary bar parallel to the traction bar. and a support bar that connects both bars on the drawbar side, and the traction member always maintains a support lever having a parallelogram pantograph structure parallel to the front frame together with the trailer front frame, and also connects the support lever and the drawbar. A displacement detection sensor is installed between the drawbar and the support lever, and the displacement detection sensor detects a change in the relative position between the drawbar and the support lever due to a change in direction of the tractor, and the trailer steering operation mechanism is operated based on the displacement value. It is.

In this case, it is preferable that the displacement detection sensor uses a length measuring potentiometer that measures a change in the relative position of the draw bar and the support bar in the longitudinal direction.

[Effect]

The support lever is always parallel to the trailer front frame even when the trailer is deviated to the tractor travel line for alignment, and its position relative to the drawbar does not change. When the tractor changes direction, the above-mentioned relative positions change. By detecting this and operating the trailer's steering mechanism, the trailer changes direction to follow the tractor.

〔Example〕

1 to 4 show embodiments of the present invention. The tractor 1 is equipped with a drawbar 2 at the rear, a traction member 3 is attached to the drawbar, and a trailer 4 is connected via this traction member. The trailer 4 is equipped with wheels 5 and 6 on both sides similarly to the well-known structure.
6 is attached to one arm of each of L-shaped arms 8 and 9 which are pivotably supported on the vehicle body frame 7, and the other arm is connected by a connecting rod 10. A hydraulic cylinder 11 is attached to one arm 8 via a lever 12, and the hydraulic cylinder 11 is connected to a hydraulic electromagnetic directional control valve 13.
1 and the steering mechanism 1 by the directional control valve 13.
5.

The traction member 3 includes a traction bar 20 and a sub-bar 21 parallel to the traction bar 20. A chevron-shaped base body 22 is attached to the drawbar 2, one end of the traction bar 20 is pivotally supported on a support shaft 23 attached to the base body 22, and the other end of the traction bar 20 is mounted near the center of the front frame 24 of the trailer 4. It is rotatably fixed to the mounted mounting bracket 25 with a pin 26.
The support shaft 23 supports the center of an L-shaped support bar 27, and the sub-bar 21 has one end attached to the lever 2.
The arm 27a of one arm 27a of the arm 27a and the other end of the arm 27a of the arm 27a of the arm 27a are pivotally supported on a pin 28 of a mounting bracket 25, respectively, and are installed parallel to the traction bar 20. This sub-bar has a turnbuckle structure, and the arm 27a of the support lever 27 is connected to the pins 26 and 28 of the mounting bracket 25.
Parallel between and between. That is, the traction member 3 is composed of a traction bar 20, an auxiliary bar 21, and a support lever 27, and has a parallelogram four-bar link pantograph structure with a mounting bracket 25.
Regardless of the angle between the arm 27a and the pins 26-2
8 are always parallel.

At the tip of the other arm 27b of the support lever 27, a displacement detection sensor 30 is swingably supported by a pin. This sensor is constituted by, for example, a potentiometer for length measurement, and the movable piece 30a is a spring 3.
1 to a pin 33 of a mounting piece 32 protruding from the base body 22.

35 is a hydraulic cylinder for ridge alignment, which is provided between the traction bar 20 and the front frame 24 and connected to the electromagnetic directional control valve 36. Further, 37 is a deviation angle detection sensor, which forms an acute angle to the mounting bracket 25 with the traction bar 20 by the hydraulic cylinder 35 for ridge alignment.
This causes the trailer traveling route to be deviated from the tractor, and a sensor for angle detection is used.

In the figure, 40 indicates an arithmetic control circuit.

In the above configuration, when it is necessary to deviate the trailer 4 with respect to the tractor 1 for alignment, the traction bar 20 forms an acute angle with the mounting bracket 25 by actuation of the hydraulic cylinder 35. The amount of deviation has a correlation with the acute angle, is detected by the deviation angle detection sensor 37, and is regulated by the arithmetic control circuit 40. In this case, as described above, the arm 27a of the support lever 27 is always kept parallel and stationary as shown in FIG. 2, regardless of the angle with respect to the mounting bracket 25. Therefore, the displacement detection sensor 30 does not operate.

Next, when the tractor 1 changes direction and moves along the circular arc C shown in FIG. 3, the drawbar 2 rotates about the support shaft 23 as shown in FIG. 4. Therefore, the pin 33 provided on the mounting piece 32 moves on an arc of radius R1 centered on the support shaft 23. The displacement detection sensor 30 is connected to the arm 2 of the support lever 27.
It swings around a pin 34 at the tip of 7a.
R2 indicates the transition locus of the tip of the fixed part of the sensor.

The difference P between the radii R1 and R2 is proportional to the rotation angle α3 of the pin 33 in FIG. 4 for changing the direction of the tractor 1. Therefore sensor 3
The pull-out distance of the movable piece 30a of 0 is proportional to the angle α3. This pull-out distance is converted into an electrical signal and applied to the arithmetic control circuit 40, which operates the steering mechanism 15 of the trailer 4 based on this to move the trailer 4 along a locus of a predetermined radius D. The pointing direction of the wheels 5 and 6 is changed to .

〔Effect of the invention〕

The present invention has the following effects. The traction member that pulls the trailer consists of a traction bar, an auxiliary bar, and a support lever, and has a parallelogram pantograph structure together with the front frame of the trailer. The change does not displace the support bar parallel to the trailer front frame and therefore does not change its position relative to the tractor drawbar. Therefore, the drawbar changes its position relative to the support lever only when the tractor changes direction, and by detecting this change, the steering mechanism is operated to guide the trailer along a predetermined travel path, which is different from the conventional method. The angle between the traction rod that pulls the trailer and the tractor travel axis (Hitschi angle) is the sum of the angle for ridge alignment and the angle for changing the direction of the tractor, eliminating the drawback that it takes time to sort them out. be able to.

Further, according to the present invention, the relative position between the drawbar and the support lever can be reliably measured by using a length measuring potentiometer.

Further, a hydraulic cylinder for ridge alignment can also be provided between the traction bar and the trailer in the same manner as in the known structure, resulting in a simple structure.

[Brief explanation of drawings]

1 to 4 relate to an embodiment of the present invention, in which FIG. 1 is an overall schematic explanatory diagram, FIG. 2 is an explanatory diagram of the ridge alignment operation, FIG. 3 is a traveling explanatory diagram of tractor direction change, and FIG. 4 is an explanatory diagram of the operation of the displacement detection sensor, FIGS. 5 and 6 are related to a conventional example, FIG. 5 is an overall schematic explanatory diagram, and FIG. 6 is an explanatory diagram of the ridge alignment procedure. 1 is a tractor, 2 is a drawbar, 3 is a traction member, 4 is a trailer, 15 is a steering mechanism of the trailer, 20 is a traction bar, 21 is an auxiliary bar, 24 is a trailer front frame, 27 is a support lever, 30 is a displacement It is a detection sensor.

Claims (1)

[Claims] 1. In a trailer that is towed via a traction member attached to a drawbar of a tractor, the traction member includes a traction bar that connects the drawbar and the front frame of the trailer, a sub-bar parallel to the traction bar, and a drawbar side. and a support bar that connects both bars at the front frame, and the towing member always maintains a support lever having a parallelogram pantograph structure parallel to the front frame, and a support lever between the support lever and the drawbar. A tractor is provided with a displacement detection sensor, the displacement detection sensor detects a change in the relative position between a drawbar and a support lever due to a direction change of the tractor, and a trailer steering operation mechanism is operated based on the displacement value. Steering control device for a towed trailer. 2. The steering control device for a trailer towed by a tractor according to claim 1, wherein the displacement detection sensor is constituted by a length measuring potentiometer disposed between the drawbar and the support lever.