JPH088562Y2 - Raising control device for working unit in ground work vehicle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a lifting control device for a working unit of a ground work vehicle such as an agricultural tractor.

[Problems to be Solved by the Prior Art and Invention] Generally, in this type of ground traveling vehicle, a working unit (rotary tiller) connected to be moved up and down by a hydraulic mechanism (single-acting hydraulic cylinder) such as an agricultural tractor. etc)
The working height (plowing depth) of the machine is controlled according to the lever operating position of the position lever, which is a height control tool, or it is automatically controlled based on the set value of the working depth setter. There is something.

By the way, in this structure, since the hydraulic mechanism for raising and lowering the working unit is configured to perform the raising and lowering operation by the hydraulic pump that is operated by the engine power, the engine speed decreases due to the load acting on the working unit. In the case of (engine drop), the working unit ascends at a low speed, which lowers the followability of the working unit and lowers the tilling accuracy.

Therefore, it is proposed to output a speed command corresponding to the difference between the set value of the working depth and the detected value of the working depth to the actuator for lifting and lowering. In the case where the speed command corresponding to the magnitude of the deviation is output when there is a decrease in the above, there is a problem that the return of the engine speed tends to be delayed.

[Means for Solving the Problems] The present invention was devised with the object of providing a lifting control device for a working unit in a ground work vehicle capable of eliminating these drawbacks in view of the above circumstances. Then, an actuator for raising and lowering the working unit, which is controlled so that the deviation between the tilling depth setting value set by the tilling depth setting means and the tilling depth detecting value detected by the tilling depth detecting means is kept constant, is set to the engine power. In a ground work vehicle configured to be operated by pressure oil supplied from a hydraulic pump driven by
An engine speed for determining whether or not a rotation speed detection signal input from an engine speed detection means is in a preset rotation speed range in a rising speed adjustment mechanism for adjusting a rising operation speed for the lifting actuator. In the range determination means, and in a state where the engine speed is determined to be within the rated speed range, a higher speed command is output to the lifting actuator corresponding to the magnitude of the deviation. When it is determined that the number of revolutions is equal to or lower than the rated revolution range, speed command control means for outputting a predetermined constant speed command to the lifting actuator regardless of the magnitude of deviation is provided. It is a feature.

According to the present invention, the accuracy of the lifting control can be improved by avoiding the deterioration of the trackability of the working unit due to the decrease of the engine speed.

[Embodiment] Next, an embodiment of the present invention will be described with reference to the drawings.

In the drawings, 1 is a traveling vehicle of an agricultural tractor,
A rotary type tiller 3 is attached to the rear part of the traveling machine body 1 via an elevating link mechanism 2. The tiller 3 swings the lift arm 5 as the hydraulic cylinder (single acting) 4 expands and contracts. It can be moved up and down by movement.

A front end edge of a rear cover 7 is swingably supported by a rear end edge of an upper cover 6 provided integrally with the cultivating part 3, and the swing angle of the rear cover 7 is connected via a detection rod 8. It is adapted to be detected by a plowing depth detection sensor 9.

On the other hand, 10 is a control unit provided in the fan unit 1a of the traveling machine body 1, and the control unit 10 is composed of a micro computer or the like. Signals are input from the sensor 11, the working depth setting device 12, the automatic working depth switch 13, etc., and the lift arm 5 of the electromagnetic hydraulic valve (not shown) for switching the expansion / contraction operation of the hydraulic cylinder 4 based on these input signals. An operation command signal is output to the ascending solenoid 14 and the descending solenoid 15.

Next, the automatic plowing depth control by the control unit 10 will be described based on the flow chart shown in FIG. When the plowing depth automatic switch 13 is turned on and this control is started, first, the magnitude of the plowing depth detection value A and the plowing depth set value B are compared. here,
When both values A and B are equal (A = B), both solenoids 14 and 15 are turned off to stop the raising and lowering of the tiller 3, but the tilling depth detection value A is larger than the tilling depth set value B (A > B), it is subsequently determined whether the engine speed is in the rated speed range. If it is judged to be in the rated speed range,
The difference C between the plowing depth detection value A and the plowing depth setting value B is calculated, and the duty ratio E is calculated based on the calculated difference C.
This duty ratio E is calculated as follows. That is, the setting coefficient α is obtained based on the difference C, and the setting coefficient α is set to increase in proportion to the difference C as shown in the graph of FIG. Furthermore, the setting coefficient β is obtained based on the engine speed D detected by the engine speed sensor 11, and this setting coefficient β is increased as the engine speed D increases as shown in the graph of FIG. It is set to be inversely proportional. Then, based on the setting coefficient α and the setting coefficient β, the duty ratio (hydraulic cylinder 4
Ratio of opening the electromagnetic hydraulic valve during operation) E (E =
α × β) is calculated, but in this embodiment, this calculation is set not to be performed here. In other words, this duty ratio E is obtained by previously setting a set engine speed range such as a high speed rotation range, a rated rotation range, a low speed rotation range and a plurality of operation command signals each having a duty ratio of a predetermined width corresponding to these set ranges. The hydraulic actuator is set so as to control the operation of the hydraulic actuator based on these operation command signals in each rotation range. Based on this duty ratio E, the raising solenoid 14 is operated by inching (continuously when the duty ratio E is 1) so that the tilling section 3 is raised. That is, in the automatic plowing depth control, the ascending / descending speed of the tilling part 3 is the plowing depth detection value A and the plowing depth set value B.
The larger the difference C, the faster the control (deviation control). However, if the engine speed D changes, the change in the ascending speed due to the change in the amount of oil discharged from the hydraulic pump can be corrected. The duty ratio E is calculated, and the hydraulic cylinder 4 is operated based on this to raise the tiller 3.

On the other hand, when it is determined that the engine speed is equal to or lower than the rated speed range, the operation control of the hydraulic actuator is set based on a predetermined duty ratio E set in advance. (It should be noted that the control procedure when the plowing depth detection value A is smaller than the plowing depth set value B is based on the same control concept as the conventional one, and therefore the description thereof is omitted.) The present invention configured as described above In the embodiment, in the automatic plowing depth control, the ascending / descending speed of the plowing part 3 is controlled based on the deviation between the plowing depth detection value and the plowing depth setting. When the rotation speed changes, for example, when this is a decrease in the rotation speed, the control unit 10 calculates a duty ratio larger than the duty ratio before the decrease in the rotation speed and operates the hydraulic cylinder 4 based on this to calculate the duty ratio. It is possible to prevent the ascending speed of the cultivating unit 3 from decreasing as the rotation speed decreases.
Therefore, it is possible to reliably prevent deterioration of the followability of the tilling part 3 due to the decrease of the engine speed, and as a result, the accuracy of the automatic plowing depth control is improved, and stable and efficient ground work can be performed. it can. Moreover, since the rising speed of the tilling part 3 does not slow down when the engine speed decreases,
When the load received by the cultivating unit 3 is the cause of the decrease in the rotation speed, this can be avoided and a quick rotation return can be performed.

Further, in the present embodiment, not only when the engine speed decreases, but also when the engine speed increases, the duty ratio is controlled so as to be small. Therefore, the so-called hunting due to the rapid up and down movement of the tiller 3 is performed. The phenomenon can be surely prevented.

On the other hand, when the rotation speed is below the rated speed range, the control is performed based on the predetermined duty ratio without corresponding to the deviation, and the rising operation is controlled at the preset pressure oil supply ratio. As a result, with respect to the recovery of the engine speed to the rated speed range, it is possible to avoid the thing that tends to be delayed when the deviation is small in the deviation control state as it is, and to perform the rapid speed recovery.
It is also possible to freely perform a combination such as doing.

[Advantageous Effects] In summary, since the present invention is configured as described above, when operating the actuator for raising and lowering the working part by the hydraulic pump driven by the engine power, the engine speed is within the rated rotation range. In this case, the elevating actuator is operated in a pressure oil supply state corresponding to the magnitude of the deviation, so that a proper ascending operation can be performed quickly.

On the other hand, when the engine speed falls below the rated speed range, the lifting actuator is controlled to rise at a preset pressure oil supply rate without responding to the deviation. With respect to the recovery of the engine speed to the rated speed range, it is possible to avoid a thing that tends to be delayed when the deviation is small in the deviation control state as it is, and to recover the speed quickly.

[Brief description of drawings]

FIG. 1 shows an embodiment of a lifting control device for a working unit in a ground work vehicle according to the present invention. FIG. 1 is an overall side view of an agricultural tractor to which a rotary tiller is connected,
2 is a block diagram showing the main part of the control mechanism, FIG. 3 is a flow chart diagram showing the control procedure in the automatic plowing depth control,
FIG. 4 is a graph of the setting coefficient α, FIG. 5 is a graph of the setting coefficient β, FIG. 6 is a timing chart showing the rated speed, and FIG. 7 is a timing chart showing the speed decreasing. . In the figure, 1 is a traveling body, 3 is a tilling part, 4 is a hydraulic cylinder,
Reference numeral 7 is a rear cover, 9 is a tilling depth detection sensor, and 10 is a controller.

Claims (1)

[Scope of utility model registration request] 1. A plowing depth set value set by plowing depth setting means,
The actuator for lifting and lowering the working unit, which is controlled to keep the deviation from the value of the working depth detected by the working depth detection means, is configured to be operated by the pressure oil supplied from the hydraulic pump driven by the engine power. In the ground work vehicle comprising the above, whether or not the rotation speed detection signal input from the engine rotation speed detection means is within a preset rotation speed range in the rising speed adjustment mechanism for adjusting the rising operation speed for the lifting actuator. In the state where the engine speed is determined to determine whether or not the engine speed is within the rated speed range, the higher the speed corresponding to the magnitude of the deviation, the greater the deviation with respect to the lifting actuator. Although the command is output, when the engine speed is judged to be below the rated speed range, it does not depend on the magnitude of the deviation from the lift actuator. Working unit increase control apparatus in ground work vehicle, characterized by comprising a speed command control means for outputting a constant speed command because set.