JPS5828121B2 - Vehicle horizontal control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a horizontal control device for a vehicle such as a tractor, which improves responsiveness and eliminates erroneous detection of inclination angle due to vibration or the like.

For vehicles such as tractors that work on uneven or sloping ground,
A hydraulic cylinder that raises and lowers the wheels (traveling device) relative to the vehicle body and a tilt detector that detects the tilt of the vehicle body are provided. Hydraulic cylinders are extended and contracted to automatically control the vehicle body horizontally at all times, but conventionally, pendulum type detectors have been used as inclination detectors, so there is a risk of malfunction due to vibrations of the vehicle body. In order to prevent this, the pendulum is placed in the liquid.
Although malfunctions caused by microvibrations could be resolved, there was a drawback in that responsiveness was significantly reduced.

The present invention has been made to solve these conventional problems, and its features include hydraulic cylinders that raise and lower each traveling device relative to the vehicle body, and electromagnetic valves that control each hydraulic cylinder. A control unit is provided with a pressure detector that detects the working oil pressure in each hydraulic cylinder, and a control unit that determines the inclination based on the signal from each pressure detector and operates each solenoid valve so that the vehicle body is leveled. A position detector is provided to detect the upper and lower limits of each hydraulic cylinder, and the control section is stopped by a signal from the position detector.

Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.
In the figure, 1 is a tractor body and 2L.

2R is the left and right front wheels, which are attached to the tractor body 1 via parallel link mechanisms 3L and 3R, and are connected to a hydraulic cylinder 4L.
, 4R allows it to be raised and lowered freely.

5L. 5R is the left and right rear wheels, and like the front wheels 2L and 2R, they are connected to the tractor body 1 via parallel link mechanisms 5L and 5R.
It is attached to the housing and can be raised and lowered by hydraulic cylinders 7L and 7H.

Note that the steering system, power system, etc. are omitted from illustration.

FIG. 2 shows a hydraulic circuit, each hydraulic cylinder 4L.

4R17L, 7R are controlled by electromagnetic valves 8L, 8R19L, 9R, and their respective hydraulic cylinders 4L.

4R17L, 7R have pressure detectors 10L, 10R111L, 11R that detect the internal working oil pressure, and telescopic (
Position detector 12L, 1 that detects the limit position of (up/down) operation
2R, 13L, and 13R are provided, respectively.

14 is the engine, 15 is the hydraulic pump, 16 is IJ IJ
-It's a frank phrase.

Reference numeral 17 denotes a front-rear distribution valve for distributing hydraulic oil from the hydraulic pump 15 to a front wheel system and a rear wheel system.

Reference numerals 18 and 19 denote left and right distribution valves for distributing the hydraulic oil distributed by the front and rear distribution valve 17 to the left system and the right system, respectively.

Note that the position detectors 12L, 12R, 113L, and 13R are composed of limit switches and the like, and may be operated by movable members.

FIG. 3 shows a block diagram of the control system, where 20 is a control section;
Inclination angle voltage generation circuit 21. It includes a disconnection detection circuit 22, a slope discrimination circuit 23, a hysteresis circuit 24, a standard slope pattern generation circuit 25, and the like.

The inclination angle voltage generation circuit 21 includes pressure detectors 1 for each of the front and rear wheels.
It generates voltage signals according to signals from 0L, 10R1IIL, and 11R.

Note that in a tractor or the like, the rear wheel load is much larger than the front wheel load, so the pressure detection value is determined by the pressure detector 10L.

Naturally, the pressure detectors 11L and 11R side are smaller than the 10R side, but in such a case, this voltage generation circuit 21
The load difference is corrected to make it an equal load, and a voltage signal is generated based on this.

The standard slope pattern generation circuit 25 generates a standard slope pattern signal, and is used to generate a standard slope pattern signal.
If there are signals from R113L and 13R, generation of the slope pattern signal is stopped.

The inclination determination circuit 23 determines the inclination of the vehicle body 1 in the left-right or front-rear direction based on the voltage signal from the voltage generation circuit 21, compares the inclination angle with the inclination pattern signal, and generates the control signal necessary at that time. be.

Reference numeral 26 denotes a drive circuit for the solenoid valves 3L, 3R, 19L, and 9R, which has a large number of elevation switching contact groups, and is configured to switch the corresponding electromagnetic valve in the ascending or descending direction when a signal is received from the inclination discrimination circuit 23. There is.

Reference numeral 21 denotes a control panel, and this control panel 27 is provided with an automatic left/right switch 28 and a front/rear/left/right switch 29, as well as a manual switch 30 and its respective front/rear wheel elevation changeover switch 3.
1L.

31R, 132L, and 32R are provided.

When the left/right switch 28 is pressed, horizontal control of the vehicle body 1 is performed in the left and right directions, and when the front/rear/left/right switch 29 is pressed, horizontal control of the vehicle body 1 is performed in the front/rear and left/right directions. An automatic indicator lamp 33,34 is connected to indicate the selection.

Changeover switch 31L, 31R132L. 32R has the vehicle body 1 and front wheels 2L on the control panel 27.

2R, rear wheels 5L, and SR are displayed in Figure 35, and the front wheels 2
They are provided at each position of L, 2R and rear wheels 5L, 5R, and when in manual mode, if you press the manual switch 30 and then switch the tilting selector switch to rise or fall, the corresponding electromagnetic The valve is adapted to operate in a predetermined direction.

36 is a power supply device, 37 is a main switch, and 38 is an alarm device.

Next, the effect will be explained.

In the case of automatic control, horizontal control on the left and right and horizontal control on the front, back, left, and right are possible, and these are selected using switches 28 and 29.

When horizontally controlling the vehicle body 1 in the front, back, left, and right, the switch 29 is pressed in advance before traveling, and then the vehicle starts traveling.

Now, suppose that the front wheel 2L is lowered and the vehicle body 1 is tilted toward the front wheel 2L. At this time, the center of gravity G of the vehicle body 1 is the front wheel 2L.
As it moves slightly to the L side, hydraulic cylinders 4L and 4R17
Among the hydraulic cylinders L and 7R, the working oil pressure in the hydraulic cylinder 4L increases, and the working oil pressure in the hydraulic cylinders 4R, 7L, and 7R relatively decreases.

Therefore, each hydraulic cylinder 4L, 4R. Pressure detectors 10L, 10R1ilL, 1 that detect the working oil pressure in γL, 7R
For the output of 1R, pressure detector 10L is a dog, pressure detector 10
R, 11L.

11R appears as a small value, and each output thereof is sent to the voltage generating circuit 21.

The voltage generation circuit 21 generates a voltage signal according to each output and sends the voltage signal to the slope discrimination circuit 23, so the slope discrimination circuit 23 compares the slope pattern signal from the slope pattern generation circuit 25 with the voltage signal. The actual inclination direction and inclination angle of the vehicle body 1 are determined by appropriate calculation processing such as determination, and the solenoid valve 3L is lowered and the solenoid valves 3R, 9L, 9 are lowered.
A control signal is generated indicating that the solenoid valves R should be switched in the upward direction, and therefore the solenoid valve 3L is switched in the downward direction via the drive circuit 26, the hydraulic cylinder 4L is extended, the front wheel 2L is lowered, and the solenoid valve 3R is switched in the downward direction. , 9L, and 9R switch to the upward direction, and the hydraulic cylinders 4R, 7L, and 7R contract, and the front wheel 2
Since R and the rear wheels 5L and 5R rise, the vehicle body 1 gradually returns to horizontal.

When the vehicle body 1 returns to the horizontal position, the center of gravity G also returns, so that the internal pressures of the hydraulic cylinders 4L, 4R, 17L, and 7R become equal, and the control is completed at that point.

The inclination of the vehicle body 1 is very steep, and the hydraulic cylinders 4L and 4
If R17L and 7R do not return to the horizontal position even after being extended and contracted to the maximum, position detectors 12L and 12R113L are used to detect the hydraulic cylinders that have been extended and contracted to their maximum extent.

13R, the detection causes the inclination pattern generation circuit 25 and the inclination discrimination circuit 23 to stop the control function and generate a neutral return signal, and each electromagnetic valve 8L, 8R19L,
Return 9R to neutral.

Therefore, in such a case, the operator must take appropriate measures such as promptly moving the vehicle to another flat area.
This is done after an alarm is given by an alarm device 38 such as an indicator light.

As described in detail in the embodiments above, according to the present invention, the working oil pressure in the hydraulic cylinder is detected by a pressure detector, and the inclination is determined based on the relative difference between the detected values, so that malfunctions due to vibration are avoided. In addition, the responsiveness during detection can be improved.

In addition, if an automatic control system is used to detect the inclination of the vehicle body and return it to the horizontal position, the control is constantly being performed, so it is not possible to know the angle of inclination of the ground just by looking at the vehicle body.
It was thought that a mistake could be made on a steep slope, etc., but in the present invention, when the hydraulic cylinder expands and contracts to its limit, a position detector detects this and stops the control function of the control unit. This prevents the above-mentioned error in judgment and also prevents the IJ-F valve in the hydraulic system from opening and causing the oil temperature to rise.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention; FIG. 1 is a front view of a vehicle, FIG. 2 is a circuit diagram of a hydraulic system, and FIG. 3 is a block diagram of an electrical system. 1...Vehicle body, 2L, 2R...Front wheel, 4
L, 4R. 7L, 7R...Hydraulic cylinder, 5L, SR...
... Rear wheel, 8L, 8R, 9L, 9R ... Solenoid valve, 10L. 10R, 11L, 11R... Pressure detector, 12
L. 12R, 13L, 13R...Position detector, 20
...control section, 21 ... slope angle voltage generation circuit, 23 ... slope discrimination circuit, 25 ...
・Standard slope pattern generation circuit.

Claims (1)

[Claims] 1 Equipped with a hydraulic cylinder that raises and lowers each traveling device with respect to the vehicle body, and a solenoid valve that controls each hydraulic cylinder, a pressure detector that detects the working pressure in each hydraulic cylinder is provided, and a pressure sensor that detects the working pressure in each hydraulic cylinder is provided. A control unit is provided to determine the inclination based on the signal from the above and operate each electromagnetic valve so that the vehicle body is horizontal.A position detector is provided to detect the lifting limit of each hydraulic cylinder. A horizontal control device for a vehicle, characterized in that a control section is stopped.