JPS6146083B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention switches and operates an electromagnetic valve based on the detection result of a height above ground sensor to control the operation of a hydraulic system for lifting and lowering a working part, thereby keeping the height of the working part above the ground constant. The present invention relates to a working part height control mechanism in a mobile working machine configured to maintain the working part height within a range.

This control mechanism was developed to automatically correct changes in the height of the working section due to changes in the amount of sinking of the aircraft into the ground, unevenness of the ground, etc. It is.

In recent years, in consideration of the fact that even if the height changes suddenly, it is better not to perform control for this, it is possible to perform better control overall, and to generate a lift command signal from the sensor. The electromagnetic valve of the lifting hydraulic system is operated when a signal is continuously generated for a predetermined period of time or more.

However, in the lifting hydraulic system, the working part is raised or lowered at a desired time, that is, when a signal is continuously generated for a certain period of time after the raising/lowering command signal is generated, due to oil leakage in the valve or the like. However, since the delay in operation tends to occur at the same time, and this delay in operation changes depending on various conditions such as the time elapsed since the last operation, it is difficult to perform stable control.

The present invention has been made with the above-mentioned circumstances in mind, and provides a working part height control mechanism for a mobile working machine having the above-mentioned structure, based on the generation of a lifting command signal from the sensor, without any time delay. Alternatively, the electromagnetic valve is operated for a very short time with an extremely small time delay, and furthermore, the electromagnetic valve is configured to be operated when a signal is continuously generated for a certain period of time from the time when the elevating command signal is generated. .

That is, when a lift command signal is generated from the sensor, the electromagnetic valve is first operated for a short period of time to warm up, so the signal is generated continuously for a certain period of time from the time the signal is generated. When the workpiece is raised and lowered by operating the electromagnetic valve, stable raising and lowering control can be achieved at all times.

Furthermore, according to the present invention, even if the height of the working part suddenly changes within a certain period of time, the solenoid valve is operated for only a short period of time as described above, so that the work part cannot be damaged due to oil leakage. This can also have the effect of compensating to some extent for an unexpected drop in the amount of water.

Embodiments of the present invention will be described in detail below with reference to the drawings.

The figure shows a device 3 for raising planted stem culms into an upright position, a reaping device 4 for cutting the base end of the raised stem culms, A reaping section 7 consisting of a device 6 etc. that vertically conveys the reaped stem culm to the feed chain 5 of the rear threshing device 2.
indicates a combine that is connected and equipped.

The reaping section 7 is supported via an elevating frame 8 which is pivotally connected to the main machine so as to be able to swing up and down, and the cutting position of the planted stem culm can be changed in the culm length direction by adjusting the elevating and lowering. The height control mechanism of the reaping section 7 described below is configured to automate this cutting height adjustment.

That is, a hydraulic cylinder 9 interposed between the elevating frame 7 and this machine, electromagnetic valves 10a and 10b that control expansion and contraction of this cylinder 9, and other hydraulic equipment such as a hydraulic pump (not shown) to the reaping unit 7. The drive lifting mechanism is composed of
Operate the lifting solenoid valve 10a to raise the cylinder 9.
The reaping section 7 is raised as the cylinder is extended, and conversely, the reaping section 7 is lowered as the lowering electromagnetic valve 10b is operated to shorten the cylinder 9.

On the other hand, the reaping section 7 is provided with a sensor 11 that is rotatably supported around a horizontal axis and detects the height above the ground by its vertical rocking displacement. As shown in the figure,
A switch mechanism 12 is provided, which has a contact a that is connected when the sensor 11 is swung upward by a certain value or more, and a contact b that is connected when the sensor 11 is swung downward by a certain value or more.

The switch mechanism 12 and the electromagnetic valves 10a and 10b are connected as shown in FIG. It is configured to be controlled to move up and down.

That is, in FIG. 2, 13a, 13b, 1
4 is a NOT circuit, 15 and 16 are NOR circuits, 17 is a delay circuit, 18a and 18b are OR circuits, 19a,
19b is an AND circuit; 20 is a pulse generator that generates a clock pulse signal of a constant period in conjunction with an appropriate shaft (for example, an input shaft) of a transmission case mounted on the machine; and 21 is a pulse signal from the pulse generator 20. a frequency divider, 22a, 2, which selects only the signals at appropriate intervals and converts them into low-frequency pulses;
2b is a counter that counts the pulse signal from the frequency divider 21 when the a contact or b contact of the switch mechanism 12 is connected, and 23a and 23b are decoders that emit a signal every time the counters 22a and 22b count up to a predetermined number of times. , 24a, 24b transmit the signal from the decoder 23a or 23b when the a contact or the b contact of the switch mechanism 12 is connected.
This is a flip-flop circuit (hereinafter abbreviated as FF circuit) that is switched to a state where the information is transmitted to the OR circuits 18a and 18b.

Therefore, when the height of the reaping section 7 changes and the contact point a or b of the switch mechanism 12 is connected, first the frequency divider 21, the counter 22a or 22b, and the decoder 2 are connected.
3a or 23b and the FF circuit 24a or 24b, the electromagnetic valve 10a or 10b is operated with very little time delay for a very short time such that the mowing section 7 is not actually moved up or down. Then, if the connection state to the a contact or the b contact is released within the time set by the delay circuit 17, the reaping part 7 will not be raised or lowered, but at a constant rate set by the delay circuit 17. If the A contact or B contact continues to be connected for more than an hour,
The electromagnetic valve 10a or 10b is continuously operated to raise or lower the reaping section 7, and the height of the reaping section 7, that is, the vertical swing position of the sensor 11 is returned to within an appropriate range.

In addition, FIG. 3 shows a signal A generated when the a contact or the b contact of the switch mechanism 12 is connected;
This is an example of a signal B that is actually transmitted to the valve 10a or 10b in response to the signal A.

Incidentally, in carrying out the present invention, the pulse generator 2
0 may be implemented using an oscillation circuit that combines a resistor and a capacitor. In this case, it takes time to charge the capacitor, and the difference between the first pulse signal and the subsequent pulse signal is However, in order to prevent this, it is preferable to charge the electromagnetic valves 10a and 10b at appropriate times in the same way as operating the electromagnetic valves 10a and 10b for a short time.

Further, in the embodiment, the reaping section 7 of a combine harvester is illustrated, but the present invention may be applied to various other devices, such as a rotary tiller connected to a tractor so as to be movable up and down.

Further, in the embodiment, the electromagnetic valves 10a and 10b are operated for a short period of time for both ascending and descending, but only for ascending control, which tends to be adversely affected by the weight of the working part 7 and tends to cause delays in operation. You may do so.

[Brief explanation of the drawing]

The drawings show an embodiment of the working part height control mechanism in a mobile working machine according to the present invention, in which FIG. 1 is a side view of a combine harvester, FIG. 2 is a circuit diagram, and FIG. 3 is a signal processing state diagram. 7...Reaping section, 9...Hydraulic device for lifting and lowering, 10
a, 10b...Solenoid valve, 11...Ground height detection sensor.

Claims (1)

[Claims] 1. Based on the detection result of the ground height detection sensor 11, the electromagnetic valves 10a and 10b are switched and operated to control the operation of the hydraulic device 9 for lifting and lowering the working section 7,
In a working part height control mechanism in a mobile work machine configured to maintain the height of the working part 7 above the ground within a certain range, the working part height control mechanism is configured to maintain the height of the working part 7 within a certain range without any time delay or with very little time delay based on the generation of the raising/lowering command signal from the sensor 11. The electromagnetic valves 10a and 10b are operated for a short period of time, and furthermore, the electromagnetic valves 10a and 10b are configured to be operated when a signal is continuously generated for a certain period of time from the time when the lift command signal is generated. A working part height control mechanism for mobile working machines. 2. The control mechanism according to claim 1, wherein the working section 7 is a reaping section of a combine harvester. 3. The control mechanism according to claim 1 or 2, wherein the time delay control is performed only for ascending control.