JPS5849657B2 - ground work equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention detects fluctuations in load on an engine. A state in which a load fluctuation detection device is provided, and a position deviation detection device is provided to detect a fluctuation amount with respect to a set value of the vertical position of the ground work device relative to the machine body, and a correlation between the load fluctuation amount, the vertical position fluctuation amount, and 4 is set in advance. and is equipped with a control mechanism that automatically controls the lifting and lowering of the ground working device by operating the lifting mechanism of the ground working device so that the sum of the detection results from both the detection devices becomes a constant value. This relates to a ground-based work machine that attempts to stabilize the height above the ground as much as possible and prevent engine stoppage due to overload.

Conventionally, when performing the above control, the raising and lowering operating speeds of the lifting mechanism are set to be constant regardless of the amount of elevation, and if the operating speed is set low, the amount of elevation control may be affected. In some cases, troubles occur due to delay in operation, and
Conversely, if the operating speed is set high, the control amount will be small.
- Occasionally, the ground work equipment would overshoot and cause hunting, making stable control impossible.

For this purpose, the operating speed was set high and the control dead zone was made large to stabilize the control, but this large dead zone tends to reduce the accuracy of the ground height of the ground work equipment. This may result in poor workmanship.

Further, when a large load is applied to the engine and a large increase control amount is output, there is a risk that the engine will stop if the operating speed becomes large.

The present invention has been made to solve the above-mentioned problems, and it is possible to perform stable control without overshoot when the amount of control for lifting and lowering the work equipment is small, and also to prevent the engine from stopping even when the amount of control is too large. This is intended to enable quick and accurate control without causing any delays.

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 1 shows a ground working machine in which a rotary tilling device 1 as a ground working device is attached to the rear of a tractor 2 so that it can be raised and lowered, and the rear propulsion wheels 4, 4 and the tilling device are powered by an engine 3 mounted on the tractor 2. 1 and also drives a hydraulic pump (not shown) and operates a hydraulic control valve (described later) which is appropriately switched and activated by an electric crawling signal. The cylinder 5 is expanded and contracted to cause a lift arm 6 connected to the cylinder 5 to swing up and down, thereby driving the cultivating device 1 suspended and supported by the lift arm 6 up and down.

The hydraulic cylinder 5 is configured to be automatically tipped based on changes in the load of the engine 3 and changes in the relative height of the tilling device 1 with respect to the tractor 2, details of which are shown in the block diagram of FIG. It will be explained in.

Signal E from the detector 7 that detects the actual rotational speed of the engine 3 and signal A/)'' from the rotational speed setter 8 that sets the maximum engine rotational speed according to the accelerator setting - applied to the first subtractor 9 An engine load fluctuation detection device is provided to detect the engine load as the amount of decrease (A-E) in the engine rotational speed.

Further, the signal from the first subtractor 9 and the signal H from the plowing depth setting device 10 for adjusting the relative level of the tilling device 1 with respect to the tractor to change the target plowing depth are applied to the adder 11. , the signal from this adder 11 (A, -E
+H) and the signal L from the level detector that detects the relative level of the tiller 1 with respect to the tractor 2 is sent to the second subtractor 13.
is applied to each of the detection and setting devices 7, 8, 10 and 12.
Based on the balance of the signals from the subtractor 13, a signal for determining whether to raise or lower the tilling device 1 is taken out from the second subtractor 13 in view of the increase or decrease in the engine load and the set plowing depth value. An automatic lifting control mechanism is formed.

In other words, the signal (A-E) from the first subtractor 9 increases as the engine speed decreases, and the signal H and L is set to decrease as the plowing depth increases, and when the engine rotation speed decreases and the tilling device 1 is positioned shallower than the set plowing depth position (.
The rotational speed reduction amount (engine load) (A-E) 0) and the deviation amount from the set plowing depth of the tilling device 1 (H-L(0)) are equal (゛ and the output from the second subtractor 13 (G =A-E+H-L
) becomes zero, and it is determined that there is no need to raise or lower the tilling device 1. From this state, when the engine rotational speed decrease amount (A-E) increases, the output G from the second subtractor 13 becomes positive, and the tilling device 1 is not required to move up and down. It is determined that it is necessary to raise the device 1, and conversely, when the engine rotational speed decrease amount (1-E) decreases, the second
The output G from the subtractor 13 becomes negative, and it is determined that the tilling device 1 needs to be lowered.

Then, the lifting and lowering control of the tilling apparatus 1 is performed so that the above-mentioned balance relationship L is established based on the change in the amount of reduction in engine rotational speed accompanying the lifting and lowering of the tilling apparatus 1 and the change in the signal from the level detector 12. be.

In other words, when the output G from the second subtractor 13 is positive, the hydraulic cylinder 5
On the other hand, when the output G is negative, the lowering valve 15 of the hydraulic cylinder 5 is opened so that the lift arm 6 and the tilling device 1 are lowered by their own weight.

The ascending and descending valves 14 and 15 are controlled to ascend and descend in different ways depending on the magnitude of the output from the second subtractor 13, that is, the magnitude of the elevation control amount.

That is, the output G from the second subtractor 13 is
17, 18, and 19 apply different reference values to four comparators 20, 2L22, and 23, each of which has an input cassette, thereby determining the magnitude of the elevation control amount.

As shown in FIG. 3, while the output G is within a certain small range a in the positive and negative regions around zero, the control of both valves 14 and 15 is cut off, and a so-called neutral dead zone L is formed. be intimidated.

Further, while the output G is within a certain range b and C exceeding the neutral dead zone a in the positive region or negative region, the oscillator 20 or 2
5 is activated and the ascending valve 14 or descending valve 15
is activated intermittently.

When the output G reaches a region d or e that exceeds the intermittent operating range b or C, a continuous operating signal is transmitted to the valve 14 or 15.

In other words, in the intermittent operation ranges b and c, overall lower speed lifting control is performed compared to the continuous operation ranges d and e.

In addition to the means for performing the low-speed elevation control, in addition to intermittently operating the hydraulic cylinder 5 that operates at a constant speed as described above, the operating flow rate of the hydraulic cylinder 5 that is continuously operated is
The absolute speed of the hydraulic cylinder 5 may be reduced by limiting it using an electromagnetic flow control valve or the like.

Furthermore, if the second subtractor 13 performs only the elevation discrimination control, even if the engine rotational speed is greatly reduced, the balance relationship will be maintained and the low-speed running state or high-load state will be stably maintained, and the work efficiency will be improved. Since there is a risk that the engine speed may drop or the engine may stop, this problem is solved by the following control.

In other words, the signal from the first subtracter 9 is applied to two comparators 26 and 27 each having a different reference value stored in the cassette. The signal from the 1 subtractor 9 increases and the first
When the first reference value given by the setter 28 is exceeded and the L value becomes smaller than the second reference value given by the second setter 29, the first comparator 26 is activated and the lowering prohibition command signal is lowered. The second subtractor 13 is manually operated by the control circuit 30 for the valve 150
Even if there is a descending command from
When the signal from the first subtractor 9 exceeds the second reference value as the engine rotation speed further decreases, the second comparator 27 is activated and a forced rise command signal is issued, and based on this signal, the L.
The oscillator 31 is activated to operate the lifting valve 14 intermittently regardless of the lifting control command from the second subtractor 13.

As a result, if the amount of decrease in the engine rotational speed is smaller than the first reference value (in the range), the tilling device 1 is controlled to move up and down based on the command of the second subtractor 13, and the first In the range between the reference value and the second reference value, the tilling device 1 is raised and prohibited to lower only when there is a rising command from the second subtractor 13, and when it becomes larger than the second reference value, the second reference value The load is reduced by forcibly raising the tilling device 7 until it drops below .

As described in detail in the embodiments above, the ground work machine of the present invention has the following features:
A load fluctuation detection device that detects the amount of load fluctuation on the engine 3 and a position deviation detection device that detects the amount of fluctuation with respect to a set value of the vertical position of the ground work device 10 relative to the machine body are provided, and the load fluctuation amount and the vertical position fluctuation amount are provided. In a state where the correlation between A mechanism is provided for determining the magnitude of an automatic lifting/lowering control signal for the ground working device 1 on a ground working machine equipped with a crawler mechanism,
This is characterized in that the lifting mechanism 5 is configured to operate at a substantially low speed while the magnitude of the lifting control signal is within a certain range, and to operate at a high speed when it exceeds the certain range. When raising or lowering the ground work device 1 a little, it operates at low speed to achieve stable control that prevents overshoot, and when raising or lowering it significantly, it operates at high speed to enable quick control without delay. As a result, the dead zone setting is reduced and the ground work equipment 1
It is also easy to increase the accuracy of the 0-to-ground height position, and in particular, when a large load is applied to the engine and a large lift control signal is output, it is possible to quickly prevent the engine from stopping and recover the load. Also, during plowing work, it has less unevenness, L has a good finish, and it is easy to obtain results at Celsius.

[Brief explanation of the drawing]

The drawings show an example of implementation of the ground work machine according to the present invention, and the first
The figure is an overall side view of the riding power cultivator, FIG. 2 is a block diagram of the strut mechanism, and FIG. 3 is a diagram showing the lifting operation characteristics. 1...Ground work device, 3...Engine 5...Elevating mechanism.

Claims (1)

[Claims] 1 A load fluctuation detection device that detects the amount of variation in the load on the engine 3 and a position deviation detection device that detects the amount of variation with respect to the set value of the vertical position of the ground work device 1 relative to the aircraft are provided, and the load fluctuation amount and the vertical position are With the correlation with the amount of variation set in advance, the lifting mechanism 5 of the ground work device 1 is operated so that the sum of the detection results by both the detection devices becomes a constant value, and the ground work device 1 is automatically raised and lowered. A ground work equipment equipped with a control mechanism is provided with a mechanism for determining the magnitude of the automatic elevation control signal of the ground work equipment 1, and the magnitude of the elevation control signal is within a certain range. The ground working machine is configured to operate the lifting mechanism 5 at a substantially low speed during the period of time, and to operate at a high speed when the speed exceeds a certain range.