JPS6337214B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a blade load control device.

Generally, in civil engineering work using a bulldozer, it is preferable to always bring out the maximum working capacity, but the load adjustment of the blade to bring out the maximum working capacity cannot be determined unconditionally because it is closely related to the soil quality. Therefore, load adjustment of the blades has traditionally relied on the operator's experience and intuition.

Therefore, there was a problem in that it was not always possible to bring out the maximum working ability.

The present invention has been made in view of the above-mentioned points, and is based on the amount of strain in the coupling shaft that connects the torque converter and the transmission, and detects the dozing force that maximizes the working capacity, and uses this dozing force as a target value. It is an object of the present invention to provide a blade load control device for a bulldozer, etc., which controls the vertical movement of the blade, thereby easily increasing the maximum working capacity.

First, the principle of the present invention will be explained.

The first curve shows a running performance curve, and the curve represents the actual vehicle speed V and the dozing force F, and the curve represents the dozing force F and the dozing output P, respectively. These curves vary depending on the soil quality at the work site. Here, the dozing output P is calculated from the actual vehicle speed V and the dozing force F using the following formula.

P=K・F・V……(1) (K is a constant) In Figure 1, if the effective dosing output P that brings out the maximum working capacity is P ₀ , the dossing force at this time is f It becomes ₀ . Therefore, by controlling the lifting and lowering of the blade using the dossing force f ₀ as a target value so that the dossing force becomes f ₀ , the maximum working capacity can be achieved.

In this invention, the vehicle is test-run under various load conditions at the work site, and the dossing force and actual vehicle speed are sequentially detected, and based on the graph shown in Figure 1, the maximum amount of earthwork can be extracted. The force is determined and the lifting and lowering of the blade is controlled using this dossing force as a target value.

The present invention will be described in detail below based on one embodiment of the accompanying drawings.

First, the dozing force detection device will be explained. In this invention, the dossing force is detected by a strain gauge installed in the power line of the engine.

FIG. 2 is a block diagram showing the power line of the engine, in which the output of the engine 21 is transmitted to a sprocket 26 via a torque converter 22, a coupling shaft 24, and a transmission 25.

A strain gauge for detecting the pushing force is installed at an appropriate location on the coupling shaft 24 that connects the torque converter 22 and the transmission 25.

Generally, the amount of strain ε of the coupling shaft 24 (as shown in FIG. 3) is
Since there is a linear relationship with the torque value of 4, that is, the dossing force F, the dossing force F can be detected by detecting the amount of strain ε of the coupling shaft 24.

Note that when a strain gauge is attached to the coupling shaft 24, this strain gauge will rotate together with the coupling shaft 24, so
Unable to extract strain gauge output.

Therefore, in this invention, the coupling shaft 24
The output of the strain gauge attached to the machine is taken out using FM transmission.

FIG. 4 shows an example of the apparatus for the above-mentioned FM transmission.

The strain amount ε detected by the strain gauge 23 is applied to the FM modulator 33 via the bridge amplifier 32.

The FM modulator 33 frequency-modulates the signal corresponding to the distortion amount ε output from the bridge amplifier 32.
It is transmitted from the FM transmitter 34. FM receiver 37
A signal corresponding to the distortion amount ε transmitted from the FM transmitter 34 is received and demodulated by the FM demodulator 38.

As a result, a signal e _c corresponding to the amount of distortion, that is, the dossing force F can be obtained from the output of the FM demodulator 38.

Note that the transmitter 30 including the strain gauge 23, bridge amplifier 32, FM modulator 33, and FM transmitter 34 is disposed in the coupling shaft 24, and the receiver 31 including the FM receiver 37 and FM demodulator 38 is operated by the operator, for example. It is installed near the control panel near the.

FIG. 5 shows an embodiment in which the blade load control device of the present invention is applied to a bulldozer.

In Fig. 5, the dozing force detector 2 is the bulldozer 1.
It detects the dossing force F and outputs a signal e _c corresponding to the dossing force F. Note that as this dossing force detector 2, one as shown in FIG. 4 can be used.

The vehicle speed detector 4 outputs an actual vehicle speed signal e _B corresponding to the actual vehicle speed V _B . As the vehicle speed detector 4, for example, a vehicle-mounted Doppler radar can be used. This vehicle-mounted Doppler radar emits electromagnetic waves from the rear of the vehicle toward the ground, and outputs the bulldozer's actual vehicle speed signal e _B from the frequency difference between the emitted waves and their reflected waves. Note that the Doppler radar described above is not limited to a vehicle-mounted type, and a ground-mounted type may also be used.

First, before starting the actual civil engineering work, the operator
The bulldozer 1 is manually operated, and civil engineering work on the target road surface is attempted, for example, several times.

As a result of this civil engineering work, signals e _c and e _B are obtained at the outputs of the dossing force detector 2 and the vehicle speed detector 4, respectively.

The calculation display 5 sequentially captures and stores the plurality of signals e _c and e _B , and performs the following calculations on the stored signals e _c and e _B.

First, the calculation display 5 displays the above signal e _c and signal e _B.
Based on this, the functional relationship between the actual vehicle speed V and the pushing force F as shown in the curve of FIG. 1 is determined.

This functional relationship can be determined using a well-known interpolation technique based on the signal e _c and e _B described above.

Next, the calculation display 5 calculates the dosing force F and dosing output P depending on the soil quality of the working road surface at this time, as shown by the curve in FIG. Find the functional relationship between

Further, the calculation display 5 detects an effective dosing output P ₀ that can obtain the maximum amount of work with respect to the soil quality of the working road surface from the functional relationship shown in the curve,
Furthermore, the dosing force f ₀ corresponding to this effective dosing output P ₀ is determined.

This pushing force f ₀ is displayed on a display section provided at an appropriate location on the calculation display 5 and shown to the operator.

For this reason, the operator can test run the bulldozer 1 under various load conditions (soil types), and each time the operator can determine the dozing force sufficient to obtain the maximum amount of work under the load conditions.
f ₀ can be read from the display section of the calculation display 5.

Thereafter, the operator sets the dosing force f ₀ read from the display section of the calculation display 5 into the setting device 6.

This setting device 6 consists of a potentiometer with a dial, and the dossing force f ₀ set by the operator is outputted from the setting device 6 as a dossing force signal e _f given as a voltage value.

The signal e _f output from the setting device 6 is subtracted by the signal e _c indicating the dossing force F output from the dozing force detector 2 in the adder AP, and the deviation △e (Δe = e _f −e _c ) is applied to the control calculation section 10 via the amplifier 8 and the compensation circuit 9 (for example, performing PID compensation).

The control calculation unit 10 outputs a voltage corresponding to the input deviation Δe. Note that it is preferable that this control calculation unit 10 provide a dead zone when the deviation voltage Δe is within a small range. When the deviation voltage Δe is positive, the control calculation unit 10 outputs a positive voltage V ₀ corresponding to this deviation, and on the other hand, when it is negative, it outputs a negative voltage −V ₀ .

The output voltage of the control calculation section 10 is applied to the electromagnetic valve 12 via the drive section 11 to switch and control the electromagnetic valve 12. The solenoid valve 12 supplies oil to the hydraulic cylinder 13 to raise or lower the blade 14, and controls the load on the blade 14 so that the detected dossing force F becomes the set dossing force _f0 .

For example, if the detected dozing force F is smaller than the set dozing force _f0 , the deviation voltage Δe will be positive, and the solenoid valve 12
is switched to position 12a. As a result, the hydraulic cylinder 13 moves in the direction of contraction, and the blade 14
increases, the load becomes lighter, and the dozing force F of the bulldozer 1 increases toward the set dozing force f ₀ .

Further, when the detected dossing force F is larger than the set dossing force f ₀ , the deviation voltage Δe becomes negative and the solenoid valve 12 is switched to the position 12b. As a result, the hydraulic cylinder 13 moves in the extending direction, the blade 14 descends, the load becomes heavier, and the dozing force F of the bulldozer 1 is increased.
becomes smaller toward the set dosing force f ₀ .

As described above, the dozing force of the bulldozer 1 is controlled to the set value of the setting device 6, that is, the dozing force f ₀ when the maximum dozing output is generated.

Although the above embodiment shows the case where the present invention is applied to a bulldozer, it can be similarly applied to other earthmoving vehicles having blades, such as a motor grader.

As explained above, according to the present invention, the maximum working capacity of the vehicle can be demonstrated in response to any changes in the working soil.

[Brief explanation of the drawing]

FIG. 1 is a running performance diagram of the bulldozer, FIG. 2 is a diagram showing the mounting location of the dozing force detector according to the present invention, and FIG. 3 is a graph showing the relationship between the amount of strain ε and the dozing force F. FIG. 4 is a block diagram showing one embodiment of the dossing force detector, and FIG. 5 is an overall block diagram showing one embodiment of the blade load control device of the present invention. 1...Bulldozer, 2...Dossing force detector, 4...
... Vehicle speed detector, 5 ... Calculation display, 6 ... Setting device, 8 ... Amplifier, 9 ... Compensation circuit, 10 ... Control calculation section, 11 ... Drive section, 12 ... Solenoid valve, 1
3...Hydraulic cylinder, 14...Blade.

Claims (1)

[Scope of Claims] 1. A dossing force detector that detects the dossing force of a vehicle running against a load applied to a blade; a speed detector that detects the running speed of the vehicle; Based on the respective outputs of the dozing force detector and the speed detector when test running under the conditions, a relational expression between the dozing force under the load condition and the dossing output for obtaining the dossing force is determined, a calculator that calculates a dozing force corresponding to an effective dosing output for obtaining the maximum work amount under the load condition from the relational expression; a display that displays the dosing force calculated by the calculator; a setting device for setting the dossing force displayed on the display as a target value; and a setting device for setting the dossing force displayed on the display as a target value, and a setting device for setting the dozing force displayed on the display device as a target value, and a setting device for setting the dozing force displayed on the display device as a target value, and a setting device for setting the dozing force displayed on the display device as a target value; A blade load control device comprising: blade elevation control means for controlling elevation of the blade. 2. The dosing force detector comprises a strain meter disposed on a coupling shaft connecting a torque converter and a transmission of the vehicle, and the output of the strain meter is extracted by frequency modulation transmission. A blade load control device according to scope 1.