JPH04341107A - Position control structure of working car - Google Patents

Abstract

PURPOSE:To accurately change the position of a working device by operating a damper fixed, in parallel with a spring, between an actuator and the working device by a handling means in a specific state. CONSTITUTION:A throttling divergence of a variable throttle valve 16 in a damper 8 fixed in parallel with a spring 9 is operated by a handling means 17. The divergence of the variable throttle valve is manipulated in such a way that deadening action of the damper is strengthened by rise in sensitivity by a sensitivity changing means 19 and deadening action of the damper is weakened by reduction in sensitivity.

Description

[Detailed description of the invention]

0001

[Industrial Field of Application] The present invention relates to an actuator that changes the attitude of a ground work device with respect to the machine body, such as a riding rice transplanter or an agricultural tractor, and an actuator that maintains a predetermined attitude of the ground work device with respect to the ground. The present invention relates to a posture control structure for a work vehicle, including a posture control means for operating an actuator.

0002

[Prior Art] An example of the above-mentioned working vehicle is a riding-type rice transplanter, which controls the raising and lowering (corresponding to posture control means) of a seedling planting device (corresponding to a ground work device). ing. An example of a lifting control means for such a riding-type rice transplanter is disclosed in Japanese Utility Model Application No. 62-74508. In this configuration, a ground float (
The seedling planting device is equipped with 5) in Figure 1 of the above-mentioned publication, and the seedling planting device is controlled by a hydraulic cylinder (
It is raised and lowered by an actuator (corresponding to 1 in Fig. 2 of the above-mentioned publication). Then, the biasing force of the spring (8 in Figure 1 of the above-mentioned publication) that biases this grounding float toward the rice field is controlled by the sensitivity control lever (3 in Figure 1 of the above-mentioned publication) depending on the condition of the rice field.
0) (corresponding to a sensitivity changing means) to change the sensitivity of the lifting/lowering operation by the hydraulic cylinder.

0003

[Problem to be solved by the invention] In the above configuration,
If the mud on the rice field is hard, there may be many mud clumps scattered on the rice field, so the ground float for height detection tends to move up and down sensitively, and the seedling planting equipment also has to move up and down frequently. When operated, it is easy to cause the so-called hunting phenomenon of the seedling planting device. Therefore, in such a case, the biasing force of the spring described above is increased to prevent the grounding float from moving up and down too much (corresponding to the insensitive side of control sensitivity). On the other hand, when the mud on the rice field is soft, there are few mud clumps and the rice field is relatively smooth, so in such a case, the biasing force of the spring mentioned above should be weakened so that the ground float can move up and down sensitively. The seedling planting device is also raised and lowered in a sensitive manner (equivalent to the sensitive side of control sensitivity).

[0004] As described above, the operator performs a sensitivity change operation depending on the condition of the field, but conventional sensitivity changes are performed on the ground float side, that is, on the sensor side that detects the attitude of the ground work equipment with respect to the ground. has only been done. Therefore, depending on the conditions of the ground and the ground-based work device itself, changing the sensitivity on the sensor side alone may not be sufficient, and accurate attitude change operations may not be possible. The present invention is less influenced by the conditions of the ground and ground work equipment itself, and
The purpose is to create a configuration that allows accurate posture change operations.

[0005]

[Means for Solving the Problems] The present invention is characterized in that the posture control structure for a work vehicle as described above is configured as follows. In other words, a spring and a damper whose damping action can be changed to be strong or weak are provided in parallel between the actuator for changing the posture and the ground work device, and are linked to the operation of changing the sensitivity to the sensitive side by the sensitivity changing means. The damper is provided with an operating means for automatically operating the damper to strengthen the damping action, and automatically operating the damper to weaken the damping action in conjunction with an operation for changing the sensitivity to the insensitive side.

[0006]

[Function] The damper described above generally exerts a damping effect by creating resistance proportional to the speed of its displacement, and may be used together with a shock absorbing spring that creates resistance to the displacement itself. There are many. Therefore, when configured as described above, when the sensitivity changing means is operated to the sensitive side, the damping action of the damper is automatically strengthened in conjunction with this. When the sensitivity changing means is operated to the sensitive side in this way, the actuator operates relatively frequently and the attitude changing operation of the ground work device is performed. In this case, if the damping effect of the damper is strengthened, the actuator and the ground work device will be directly connected without any spring or damper, and once the actuator starts operating, the ground work will be carried out without delay. An operation to change the attitude of the device is started. As described above, when the sensitivity change means is operated to the sensitive side, the actuator starts operating quickly without delay based on the change in the posture of the ground work device with respect to the ground, and the action of the damper described above causes the actuator to operate quickly. The robot quickly begins to change its posture without delay.

On the other hand, when the sensitivity changing means is operated to the insensitive side, the damping effect of the damper is weakened in conjunction with this. When the sensitivity changing means is operated to the insensitive side in this manner, the frequency of actuation of the actuator becomes relatively low, and the frequency of operation of changing the attitude of the ground work device also becomes low. In this case, if the damping effect of the damper is weakened, the actuator and the ground work device will be connected only by the spring, and when the actuator starts operating, the attitude change operation of the ground work device will occur with a slight delay. It will begin. As described above, when the sensitivity changing means is operated to the insensitive side, the actuator starts operating with a slight delay based on the change in the posture of the ground-based work equipment with respect to the ground, and due to the action of the damper described above, the actuator's operation is delayed. After a short delay, they begin to change their posture.

[0008]

[Effects of the Invention] Unlike the conventional configuration, the control sensitivity is not only changed only on the elevation control means side from the actuator for changing the attitude of the ground work equipment, but in addition to this control sensitivity change operation, the control sensitivity of the actuator is changed. It was possible to configure the damper to automatically change whether the ground work device quickly follows the operation or follows it with a delay. As a result, the range of sensitivity that can be applied to the entire attitude change operation of ground work equipment can be set to a wider range than before, and it is now possible to respond to various conditions of the ground and ground work equipment itself, making it possible to We were able to improve the attitude change performance of the device.

[0009]

Embodiments Hereinafter, embodiments of the present invention will be explained based on the drawings. An example of a work vehicle is a riding rice transplanter, in which a seedling planting device 1 (corresponding to a ground work device) is connected to the rear of the machine via a link mechanism 2 so as to be movable up and down, as shown in FIG. This seedling planting device 1 includes a seedling stand 4 for placing seedlings provided in a planting mission case 3, and a rotationally driven planting case 5.
It is comprised of a pair of planting arms 6, etc., which are provided at both ends of the planting case 5 and alternately take out seedlings from the seedling stand 4 and plant them on the rice field G (corresponding to the ground).

As shown in FIGS. 1 and 2, a single-acting hydraulic cylinder 7 (corresponding to an actuator) is attached to the fuselage side, and the tip of this hydraulic cylinder 7 and the link mechanism 2 connect to a damper 8, which will be described later. and are connected via a coil type spring 9. A small ground float 10 is supported at the bottom of the planting mission case 3 so as to be able to swing up and down around a rear fulcrum P1, and the front part of this ground float 10 is connected to the planting mission case 3 via a bendable link mechanism 18. A spring (not shown) that urges the front part of the grounding float 10 toward the surface G side is connected to the link mechanism 18.
It's decorated. A potentiometer 11 is provided to detect the angle of the link mechanism 18 with respect to the planting mission case 3 as the vertical position of the grounding float 10 with respect to the planting mission case 3.

With the above structure, when the control lever 12 provided on the control panel (not shown) at the front of the aircraft is operated to the planting position, the control lever 12 is activated based on the signal from the potentiometer 11 of the grounding float 10. , the seedling planting device 1 is in the field G
The control device 13 switches the control valve 14 for the hydraulic cylinder 7 to extend and retract the hydraulic cylinder 7 so as to maintain the set height from the height, thereby controlling the raising and lowering of the seedling planting device 1 (corresponding to attitude control means). will be held. And the operation lever 12
By operating the seedling planting device 1 to the raised position U, neutral position N, and lowered position D, the seedling planting device 1 can be forcibly raised and lowered, and in this state, the raising and lowering control is stopped.

This elevation control is provided with a sensitivity change function, and the structure of this sensitivity change will be explained. Figure 1
As shown in , a sensitivity control lever 19 (corresponding to a sensitivity changing means) is provided on the aircraft side.
A wire 20 is connected between the ground float 9 and the front part of the ground float 10.

With the above structure, when the sensitivity control lever 19 is operated to the sensitive side and fixed, the grounding float 10 becomes nearly parallel to the field surface G, and the grounding area of the grounding float 10 becomes wider. As a result, the grounding float 10 moves up and down sensitively, and the elevation control is performed based on this. On the other hand, when the sensitivity control lever 19 is operated to the insensitive side and fixed, the ground float 10 is raised forward with respect to the field surface G, and the ground contact area of the ground float 10 becomes narrow. As a result, the grounding float 10 becomes insensitive to vertical movement, and elevating and lowering control is performed based on this.

Furthermore, when a sensitivity change operation is performed by changing the attitude of the grounding float 10, the potentiometer 11
When performing elevation control using signals from the vehicle, the target value must also be changed. In this case, as shown in FIG.
is provided, and a signal from this potentiometer 21 is input to the control device 13. Thereby, the configuration is such that the target value for the elevation control is also automatically changed by operating the sensitivity control lever 19.

Next, the damper 8 and spring 9 attached to the tip of the hydraulic cylinder 7 will be explained. As shown in FIG. 1, the damper 8 is equipped with an internal piston (not shown).
A pair of oil chambers (not shown) are formed on both sides of the oil chamber, and a variable throttle valve 16 is installed in an oil passage 15 that connects both oil chambers.
is provided. As a result, when the damper 8 expands and contracts, hydraulic oil flows from one oil chamber to the other oil chamber or in the opposite direction through the oil passage 15, so the variable throttle valve 16 provides resistance to the flow of this hydraulic oil, and the damper This suppresses the expansion/contraction and vibration of 8.

A damper 8 is connected across the tip of the hydraulic cylinder 7 and the link mechanism 2, and a spring 9 is fitted on the outside of the damper 8. As a result, the damper 8 and the spring 9 are attached across the tip of the hydraulic cylinder 7 and the link mechanism 2 in a parallel state.

The throttle opening of the variable throttle valve 16 in the damper 8 can be set to any desired opening by an actuator 17 (corresponding to an operating means). Then, when the sensitivity control lever 19 is operated to the sensitive side and fixed, the variable throttle valve 16 is operated to the closed side by the actuator 17 in conjunction with this, and a large resistance is applied to the expansion and contraction of the damper 8. In other words, the damping effect of the damper 8 becomes stronger.

In this state, as described above, the grounding float 10 sensitively moves up and down following the surface G, and accordingly, the hydraulic cylinder 7 is expanded and retracted relatively frequently. In this case, when the variable throttle valve 16 is operated to the closed side, the hydraulic cylinder 7 and the link mechanism 2 are directly connected without using the spring 9 or the damper 8, and the hydraulic cylinder 7 becomes When the expansion and contraction start, the link mechanism 2 and the seedling planting device 1 are lifted and lowered without delay. In this way, changes in the vertical position of the seedling planting device 1 with respect to the field surface G are sensitively detected by the ground float 10, and at the same time, the link mechanism 2 and the seedling planting device 1 are quickly operated up and down by the hydraulic cylinder 7 without delay. So do it.

On the other hand, when the sensitivity control lever 19 is operated to the insensitive side and fixed, the variable throttle valve 16 is operated to the open side by the actuator 17 in conjunction with this, and the resistance applied to the expansion and contraction of the damper 8 is small. Become something. In other words,
The damping effect of the damper 8 becomes weak.

In this state, as mentioned above, the grounding float 10 follows the ground surface G insensitively,
This insensitive vertical movement of the ground float 10 reduces the frequency of expansion and contraction of the hydraulic cylinder 7. In this case, if the variable throttle valve 16 is operated to the open side, the hydraulic cylinder 7 and the link mechanism 2 will be in a state where they are connected only by the spring 9, and when the hydraulic cylinder 7 starts to expand or contract, it will slightly The link mechanism 2 and the seedling planting device 1 are lifted and lowered after a delay. In this way, the seedling planting device 1 for the field G
When a change in the vertical position of the plant is detected by the ground float 10, the detection is made insensitive, and at the same time, the link mechanism 2 and the seedling planting device 1 are moved up and down by the hydraulic cylinder 7 with a slight delay.

[Another Embodiment] In the above-mentioned embodiment, the damper 8 of the present invention was provided to control the raising and lowering of the seedling planting device 1. In addition to being attached for rolling operation, an actuator and the damper 8 of the present invention may be provided for this rolling operation. Furthermore, in the above embodiment, Tanabe G
The sensitivity change operation was carried out by changing the attitude of the grounding float 10 up and down against the ground surface G. However, the sensitivity changing operation was carried out by changing the biasing force of the spring that biases this grounding float 10 toward the surface G side (increasing the biasing force of the spring). It is also possible to make the sensitivity insensitive and to make the sensitivity sensitive by weakening the biasing force of the spring. Alternatively, the sensitivity may be changed depending on the flow rate of the hydraulic oil supplied to the hydraulic cylinder 7 (sensitivity is sensitive when the flow rate is high, and sensitivity is insensitive when the flow rate is low). The present invention may be applied not only to a riding rice transplanter but also to lifting control or rolling control of a rotary tiller (equivalent to a ground work device) in an agricultural tractor equipped with a rotary tiller (corresponding to a ground work device).

[0022] Although reference numerals are written in the claims for convenience of comparison with the drawings, the present invention is not limited to the structure shown in the accompanying drawings.

[Brief explanation of drawings]

[Fig. 1] Schematic circuit diagram showing the relationship among the hydraulic cylinder for lifting/lowering operation, damper, spring, sensitivity control lever, etc.

[Figure 2] Overall side view of riding rice transplanter

[Explanation of symbols]

1 Ground work equipment 7 Actuator 8 Damper 9 Spring 17 Operation means 19 Sensitivity change means G Ground

Claims (1)

[Claims] Claim 1: An actuator (7) for changing the attitude of the ground work device (1) with respect to the aircraft, and a ground (G)
attitude control means for operating the actuator (7) so that the ground work device (1) maintains a predetermined attitude against the ground, and a sensitivity changing means (19) capable of changing the control sensitivity of the attitude control means. A posture control structure for a working vehicle equipped with a spring (9) and a damper (8) whose damping action can be changed to be strong or weak are arranged in parallel between the actuator (7) and the ground work device (1). At the same time, the damper (8) is automatically operated to strengthen the damping action of the damper (8) in conjunction with the operation of changing the sensitivity to the sensitive side by the sensitivity changing means (19), and the sensitivity is changed to the insensitive side. A posture control structure for a working vehicle, comprising an operating means (17) that automatically operates the damper (8) to weaken the damping action in conjunction with the operation.