JPS6314926B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an automatic lifting control device for ground working equipment configured to automatically stop a hydraulic actuator for lifting the ground working equipment when the ground working equipment reaches a set lowering position during a lowering operation. The purpose of this is to enable the ground work device to be lowered to the set position accurately and to ensure that such a good operating condition is always obtained.

More specifically, the automatic elevation control device includes:
This was designed to simplify the operation when lowering the ground work equipment to the set position, but conventionally, the lowering speed of the ground work equipment was generally quite high regardless of the vertical position in order to improve work efficiency. Because of this setting, overrun etc. tend to occur and the ground work equipment cannot be lowered to the set position accurately, and there is also the problem of generating a large impact when the lowering is stopped.The present invention solves these problems. The purpose is to

The present invention provides an elevation control device for a ground work machine having the above-mentioned structure, in which the ground work equipment is configured to maintain a descending speed in a range near a set lowering position of the ground work equipment at a set speed that is lower than a descending speed in other ranges. The present invention is characterized in that a mechanism is provided that automatically changes the operating speed of the hydraulic actuator based on the detection result of the mechanism that detects the actual lowering speed of the working device.

In other words, since the configuration is such that the descending speed in the range near the set descending position is automatically lower than the descending speed in other ranges, it minimizes the risk of overruns or shocks while avoiding a decrease in work efficiency. I was able to reliably solve this problem. Particularly, according to the present invention, by providing a mechanism that automatically changes the operating speed of the hydraulic actuator based on the detection result of the mechanism that detects the actual descending speed of the ground work device, the range near the set descending position can be adjusted. The lowering speed of ground work equipment can always be maintained at the set speed without being adversely affected by changes in oil viscosity due to changes in temperature, etc., and automatic lifting and lowering control of ground-based work equipment can now be performed with even higher reliability. .

Embodiments of the present invention will be described below based on illustrative drawings.

FIG. 1 shows a side view of a riding-type tiller as an example of a ground-working device. A rotary tiller 2, which is an example of a ground-working device, is connected to the rear of a tractor 1 via a lift arm 3 so that it can be raised and lowered. There is. The lift arm 3 is operated to swing up and down by a single-acting hydraulic cylinder 4 as a hydraulic actuator, and an electromagnetic switching valve 5 that controls the cylinder 4 is operated by a microcomputer as shown in FIG. It is connected to a control circuit configured as follows.

In the figure, reference numeral 6 denotes a variable low resistance device as a setting device for setting a set lowering position (working depth), which is provided near the control section of the tractor 1 and can be changed and adjusted as desired. Numeral 7 is a potentiometer as a working depth detection sensor, and its output changes according to the amount of vertical swing of the tilling cover 8 that follows the ground contact. (See Figure 1) Reference numeral 9 is a subtraction circuit that calculates the difference between the setting signal from the setting device 6 and the detection signal from the sensor 7, and the deviation amount of the detected working depth from the set working depth is extracted here. be done. Reference numeral 10 designates a rise determination circuit that compares the output signal from the subtraction circuit 9 with the rise reference signal, and 11 represents a similar descent determination circuit, which determines whether to raise, lower, or maintain neutrality based on the deviation from the set working depth. It is determined here whether it is necessary.
12 is a rising current amplification circuit connected to the rising discrimination circuit 10; 13 is a falling current amplifying circuit connected to the falling discrimination circuit 11; outputs from the rising or falling discrimination circuits 10 and 11; , and the upward excitation section 14 or the downward excitation section 15 of the electromagnetic switching valve 5 is driven. Reference numeral 16 designates a forced rise switch which, when closed, directly activates the rise current amplification circuit 12 and also checks the operation of the fall current amplification circuit 13, and is provided near the control section.

When the raising switch 16 is switched from the raising operation state to the lowering operation state, the hydraulic cylinder 4, which is shortened due to the weight of the tilling device 2, is configured to be automatically stopped when the tilling device 2 reaches the set position. Moreover, when the working depth changes due to the tractor 1 tilting back and forth, etc., the hydraulic cylinder 4 is automatically operated to maintain the plowing depth constant.

Further, the detection signal from the sensor 7 is sent to the setting device 17.
is compared with the reference signal given by the comparison circuit 18, and if the detection level is lower than the set level,
That is, when it is determined that the rear cover 8 has been upwardly swung by a certain amount or more and the tilling device 2 has descended to a range near the set lowering position, the intermittent signal generating circuit 19 connected to the comparison circuit 18 is activated. In addition, the intermittent signal generation circuit 19 is connected to the falling current amplification circuit 13. When the lowering determination circuit 11 operates while the intermittent signal generation circuit 19 is activated, the valve is driven intermittently and the hydraulic cylinder 4 is operated intermittently, resulting in the set lowering position of the tiller 2. The detection result of the mechanism 20 that detects the actual descending speed of the tilling device 2 is configured so that the descending speed in the vicinity is lower than the descending speed in other ranges, and in order to maintain this low descending speed at the set speed. A mechanism is provided for automatically changing the operating speed of the hydraulic cylinder 4 based on the above.

That is, the descending speed detection mechanism 20 calculates the amount of change per unit time in the output from the potentiometer 21 (see FIG. 1) that detects the swing angle of the lift arm 3, and calculates the actual descending speed. The detection mechanism 20 operates only when the tilling device 2 is lowered within a range near the set lowering position based on the signals from the lowering determination circuit 11 and the comparator 18. It is structured as follows. Then, the signal of this detection mechanism 20 is discriminated from the signal of the setting device 22 by the comparator 23, and
Based on the discrimination signal from the comparator 23, a circuit 19a for correcting the number of signals generated per unit time by the intermittent signal generating circuit 19 is configured to be automatically activated.

24 in the figure is a changeover switch that inputs the signal from the potentiometer 21 to the subtraction circuit 9 instead of the signal from the potentiometer 7. The elevator is raised and lowered based on this, and so-called position raising and lowering control is performed.

[Brief explanation of the drawing]

The drawings illustrate an embodiment of the automatic elevation control device for a ground-based work machine according to the present invention, and FIG. 1 is a side view of a riding type cultivator, and FIG. 2 is a block diagram. 2...Ground work device, 4...Hydraulic actuator, 20...Descent speed detection mechanism.

Claims (1)

[Scope of Claims] 1. An automatic lift control device for a ground work machine configured to automatically stop a hydraulic actuator 4 for raising and lowering the ground work machine 2 when the ground work machine 2 reaches a set lowering position during a lowering operation. A mechanism 20 for detecting the actual descending speed of the ground working device 2 in order to maintain the descending speed in a range near the set descending position of the ground working device 2 at a set speed lower than the descending speed in other ranges. An automatic elevation control device for a ground-based work machine, comprising a mechanism for automatically changing the operating speed of the hydraulic actuator 4 based on the detection result. 2. The automatic elevation control device for a ground-based work machine according to claim 1, wherein the automatic operating speed changing mechanism is configured to change the number of operating times per unit time of the hydraulic actuator 4 that is operated intermittently.