JPS597282B2 - earthmoving vehicle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an earthmoving vehicle in which a ground working device is connected to a vehicle body such as a tractor equipped with a rotary tilling device so as to be movable up and down.

In the above-mentioned earthmoving vehicle, if the working equipment is lowered rapidly while entering the ground, the engine load increases rapidly and the engine stops unexpectedly.On the other hand, if the lifting speed of the ground working equipment is always low, However, there is a drawback that it takes time to raise and lower the ground work equipment when turning, etc., and work efficiency decreases.

A possible solution to the above problem is to indirectly detect the ground level of the ground work equipment based on level detection with respect to the vehicle body, and to lower the ground work equipment at a low speed when it is below the target ground level. However, when the vehicle body is tilted to the ground, due to the above indirect detection,
In reality, there is a risk that the ground work equipment will be lowered at high speed even though it is located below the target ground level.

In addition, even if the vehicle body is not tilted, the low speed descent start level of the ground work device is constant, so setting the low speed descent start level high is useful when the ground is soft and the ground work depth is set to dog. If the lowering of the work equipment to the specified level takes more time than necessary, and conversely, if the low-speed descent start level is set low, the engine may stop when the ground is hard, etc. Despite this, it is not possible to always lower the ground work equipment as efficiently as possible while also reliably avoiding unexpected engine stops.

Furthermore, as shown in Japanese Patent Publication No. 48-13644, a mechanism for setting the level of the aircraft-to-aircraft of the ground-based work equipment and a mechanism for detecting the level of the aircraft-based equipment have been provided to control the level of the ground-based work equipment. Those who do, or Jikoko 51-2
As shown in Japanese Patent No. 4084, there are known devices that control ground work by providing a mechanism for setting the engine rotation speed and a mechanism for detecting the engine rotation speed.
The former of these conventional technologies allows ground work to be performed at almost the set level on soft ground, but on hard ground, the engine load increases and engine stop occurs. This makes smooth ground work difficult.

Moreover, the latter case is not suitable when it is desired to perform ground work at a certain level.

That is, in the latter case, there is a drawback that the desired level varies greatly depending on the change in engine load depending on the softness and hardness of the land.

Therefore, an aircraft level setting mechanism and an aircraft level detection mechanism of the ground work equipment are provided to control the level of the ground work equipment, and an engine rotation speed setting mechanism and an engine rotation speed detection mechanism are provided, and the The level setting mechanism is configured to restrict ground work deeper than the set level, and the ground work equipment is adjusted based on the detection result of the aircraft level detection mechanism so that ground work can be performed at the set level during normal ground work. When the engine load increases, such as when performing ground work on hard ground, the engine speed is controlled based on the deviation value between the engine speed set by the engine speed setting mechanism and the actual engine speed detected by the engine speed detection mechanism. It is also conceivable to detect the equivalent engine load and control the ground level setting value using the engine load equivalent value, thereby preventing engine stoppage and allowing ground work to be performed.
This is effective when the fluctuations in the engine load are extremely small, but in this case the ground level is only indirectly controlled for the engine load, so in ground work on hard ground, the ground level is essentially controlled only by the engine load. The problem is that the engine load fluctuation value directly becomes the level fluctuation value of the ground work, and the ground level fluctuates greatly due to the engine load fluctuation.

The present invention enables ground work to be carried out near a desired ground level depth, and performs ground work while suppressing ground level fluctuations due to changes in engine load. The object of the present invention is to provide an earthmoving vehicle that not only dynamically corrects the problem but also improves the performance of the vehicle and prevents engine stoppage.

The feature of the present invention is an earthmoving vehicle in which a ground work device is connected to the vehicle body so that it can be driven up and down, and the maximum engine speed is set according to a mechanism that detects the actual engine speed and an accelerator set. A load fluctuation detection device is provided that detects the amount of decrease in the engine speed based on the deviation of the output from the mechanism that operates, and also includes a mechanism that sets the level of the aircraft relative to the ground work equipment and a mechanism that detects the actual level of the aircraft relative to the ground work device. A position deviation detection device is provided for detecting the amount of variation in the vertical position of the ground work device relative to the aircraft body with respect to a set level based on the deviation of the output of the ground work device 4. Equipped with a control mechanism that automatically controls the elevation of the ground work equipment so that the sum of the detection results from both detection devices becomes a constant value, with the correlation with the output deviation indicating the amount of work being set in advance, and A mechanism is provided that detects that the amount of decrease in engine speed has become greater than a certain value, and that reduces the drive lowering speed of the ground work equipment when detecting the amount of decrease in engine speed that exceeds the certain value. This configuration provides the following effects.

In other words, in the case of normal ground work, the amount of decrease in engine speed due to the deviation in output from the mechanism that detects the actual engine speed and the mechanism that sets the maximum engine speed, and the amount of decrease in engine speed due to the difference in output from the mechanism that detects the actual engine speed and the mechanism that sets the maximum engine speed, and the Detection results by the load fluctuation detection device and the position deviation detection device in a state where the correlation between the amount of vertical position fluctuation due to the deviation of the output from the mechanism for setting the level of the device and the mechanism for detecting the actual level of the aircraft is set in advance. By configuring the added value of It is possible to perform ground work near the level set by the aircraft level setting mechanism, and even if the ground level increases due to an increase in engine load, the maximum engine speed setting mechanism and engine actual Due to an increase in the deviation value from the rotation speed detection mechanism, the ground work device rises, and accordingly, the deviation value between the aircraft level setting mechanism and the aircraft level detection mechanism increases, so that the two deviation values check each other. Therefore, there is an advantage that lifting of the ground work equipment due to an increase in engine load can be suppressed.

When the ground work equipment is lowered from an upper position at the start of work, the engine is in a nearly unloaded state, and the deviation value due to the engine speed is almost zero, and in effect, the command from the aircraft level setting mechanism The ground work equipment will be lowered.

When the ground work equipment enters the ground, it receives ground resistance and the engine load increases beyond a certain value, the drive lowering speed of the ground work equipment is reduced to soften the sudden increase in engine load and avoid engine stoppage. It becomes like this.

At this time, despite the decrease in the descending speed of the ground work equipment, the engine load may unexpectedly increase and the engine speed may drop sharply. When the engine is not descending, the deviation value for the engine speed increases as the engine speed decreases, and that deviation value becomes smaller due to the ground work device plunging into the ground. If this value is exceeded, the ground working equipment will stop or rise due to the balance between the output deviation due to load fluctuations and the output deviation due to positional deviation, so it has a function to reliably prevent engine stoppage, resulting in a very effective earthmoving vehicle. This not only improves work efficiency at the start of work, but also makes it possible to reliably prevent engine stoppage.

Next, embodiments of the present invention will be described with reference to the drawings.

The rotary tilling device 4, which is detachably attached to the tow vehicle 1 via a coupling device, is raised and lowered by a lift arm 3 provided at the rear of the passenger tow vehicle 1 so as to be able to swing up and down by a hydraulic cylinder 2. , the engine 6 for the drive wheels 5 of the tow vehicle 1 and the rotary tilling device 4 are interlocked and connected via a power take-off shaft provided in a traveling transmission 7,
Thus, the tilling device 4 is configured to till the field while being driven and rotated.

The hydraulic cylinder 2 is operated by pressure oil from a pump driven by the engine 6, and is configured to be automatically controlled based on changes in the load of the engine 6 and changes in the level of the tiller 40 and the aircraft. The details will be explained with reference to FIG.

A signal voltage corresponding to the actual engine rotation speed and the set engine rotation speed is first subtracted from the mechanism 8 that detects the engine 60 rotation speed and the mechanism 9 that sets the maximum rotation speed of the engine 6 according to the accelerator setting. An engine load fluctuation detection device is configured to detect the deviation between the set engine speed and the actual engine speed, that is, a decrease in the engine speed due to the work load.
A signal voltage corresponding to the setting RA is sent from the 0 to aircraft level setting mechanism 11, and this signal voltage and the first subtractor 10
The signal voltage from the adder 12 is inputted to the adder 12, and the signal voltage corresponding to the actual level is sent from the tilling device 40 to machine level detection mechanism 13, and this signal voltage and the signal voltage from the adder 12 are The husband signal voltage is sent to the subtractor 14, and the tilling device 4 is adjusted based on the balance of the signal voltages from the four mechanisms 8, 9, 11, and 13 in consideration of the set target morning depth value.
It is determined whether to raise or lower the plowing depth to form an automatic lifting control mechanism, and the level setting mechanism 11 is configured to changeably adjust the target plowing depth.

In other words, the signal voltage of the first subtractor 10 increases as the engine speed decreases, and the signal voltage from the level setting mechanism 11 and level detection mechanism 13 that constitute the position deviation detection device increases as the engine speed decreases. At the same time, the signal voltage from the bell setting and level detection mechanism IL13 is decreased as the plowing depth increases, and as a result, the tilling device 4 adjusts the level setting by an amount corresponding to the decrease in engine speed. In a state where the tiller is located shallower than the position set by the mechanism 11, the output voltage from the second subtractor 14 becomes zero, and it is determined that there is no need to raise or lower the tiller 4, and from this state, the engine speed decreases. When the output voltage from the second subtractor 14 becomes positive, and conversely, when the engine speed increases, the output voltage from the second subtractor 14 becomes negative, and it is determined that the tilling device 4 needs to be raised or lowered. This will result in

If the output voltage from the level setting mechanism 11 is changed, the above-mentioned balanced relationship is disrupted, and a signal is transmitted from the second subtractor 14 so that the balanced relationship is established again, and the actual plowing depth is changed. It can be changed.

That is, when the output voltage from the second subtractor 14 is positive, the up pulse for controlling the hydraulic cylinder 2 is opened to raise the tilling device 4, and when it is negative, it is opened to lower the tilling device. In order for the downpulve to open,
A signal is sent from the second subtractor 14 to the descending valve controller 17 and the ascending valve controller 18 via amplifiers 15 and 16.

The signal of the first subtractor 10 is also configured to be sent to first and second controllers 19 and 20 for controlling the amplifiers 15 and 16, and in the first controller 19,
It is determined whether the signal voltage from the first subtracter 10 is greater than the first setting value of the first setting device 21, and if the actual rotation speed of the engine 6 is greater, the amplifier 15 The operation of the subtractor 14 is stopped so that the tilling device 4 is not lowered even if there is a signal from the second subtractor 14.

In other words, the tilling device 4 is prevented from lowering when the actual engine speed decreases by a certain number of rotations.

Further, the second controller 20 determines whether the signal voltage of the first subtractor 10 is a dog with respect to the second set value by the second setter 22 which is larger than the first set value. If it is determined that the dog is a dog, the intensifier 16 is activated intermittently by a pulse signal, and the tiller 4 is intermittently raised regardless of the presence or absence of the signal from the second subtractor 14.

As a result, in a range where the signal voltage from the first subtractor 10 is smaller than the first set value, the tilling device 4 is raised and lowered based on the command from the second subtracter 14, and the signal voltage is lower than the first set value. For dogs, in a range smaller than the second set value, the first
When the controller 19 operates and the second subtractor 14 also has a positive output voltage, the tilling device 4 is raised and the tilling device 4 is not lowered; The second controller 20 operates until the output voltage (signal voltage) of the first subtractor 10 reaches the second set value, regardless of whether the output voltage of the second subtractor 14 is positive, negative or zero. is forced to rise.

Further, the signal voltage from the first subtracter 10 is transferred to the third controller 2.
3, and in the third controller 23,
It is determined whether the signal voltage from the first subtracter 10 is a dog based on a set value, and if it is a dog, the amplifier 15 is operated intermittently by a pulse signal, and the signal voltage from the second subtracter 14 is The tilling device 4 is configured to be lowered intermittently when a command is given.

In other words, it is determined whether the actual engine speed is lower than the maximum engine speed set by the accelerator set corresponding to the no-load state by a certain number of revolutions (for example, 20 rpm), and the engine speed is decreased by more than the certain number of revolutions. In this case, the tilling device 4 is lowered intermittently in response to a lowering signal voltage command from the second subtracter 14.

As a result, the engine descends continuously (at high speed) until it reaches the state required to prevent the engine from stopping, and after that it descends intermittently (
(Low speed) lowering is performed automatically, thereby preventing unexpected stoppage of the engine 6 while lowering the tiller 4 with the highest possible efficiency.Furthermore, since the tiller 4 is lowered as efficiently as possible, unexpected stoppage of the engine 6 is prevented. The occurrence can be suppressed.

A snap switch 24 linked to the aircraft direction mechanism is interposed between the level setting mechanism 11 and the adder 12, and when the aircraft turns, a signal from the lifting command mechanism 25 is sent to the adder 12, so that the tilling The device 4 is automatically lifted to the ground when turning, so that the tilling device 4 does not get in the way of turning.

Note that a torque detector or the like can also be used as a means for detecting the load on the engine 6.

The objects of work include various types of ground work such as digging trenches and leveling the ground, and the equipment used for these purposes is collectively referred to as the ground work device 4, and the configuration and operating state for raising and lowering the ground work device 4 can be modified in various ways. .

The work vehicles equipped with these ground work devices 4 are collectively referred to as earthmoving vehicles.

In the above-mentioned embodiment, it is also possible to have one controller 23 perform detection of a decrease in engine rotational speed and decrease the descending speed of the ground work device 4, while having a separate mechanism perform the detection. The descending speed may be lowered in a continuous low speed descending state.

[Brief explanation of the drawing]

The drawings show an embodiment of an earthmoving vehicle according to the present invention, with FIG. 1 being a side view and FIG. 2 being a block diagram showing a control system. 4...Ground work device, 6...Engine, 8...Mechanism for detecting the actual rotation speed of the engine,
9...Mechanism for setting the maximum engine speed,
11... Mechanism for detecting the level of the ground work equipment relative to the aircraft, 13... Mechanism for detecting the actual level of the ground work equipment relative to the aircraft, 23... Engine rotation Number drop detection and descending speed reduction mechanism.

Claims (1)

[Claims] 1 An earthmoving vehicle in which a ground work device 4 is connected to the vehicle body so that it can be driven up and down, and a mechanism 8 that detects the actual rotation speed of the engine 6.
and a mechanism 9 that sets the maximum rotation speed of the engine 6 according to the accelerator set. Mechanism to set 1
A position deviation detection device is provided for detecting the amount of variation in the vertical position of the ground work device 10 relative to the aircraft body with respect to the set level based on the deviation of the output from the mechanism 13 for detecting the actual level of the ground work device 10 relative to the aircraft body based on the deviation of the output from the With the correlation between the output deviation indicating the vertical position variation amount of the ground working device 4 set in advance, the ground working device 4 is set so that the sum of the detection results by both the detection devices becomes a constant value. In addition to being equipped with a control mechanism that automatically controls the elevation and descent of the An earthmoving vehicle characterized by being provided with a mechanism 23 for reducing the drive lowering speed of the working device 4.