JPH06345384A - Control device for boom drive - Google Patents

Abstract

PURPOSE:To attain boom driving with no influence by fluctuating an engine speed by supplying pressure oil to a boom driving hydraulic cylinder through a solenoid proportional valve, and controlling this valve in accordance with an output of a DA converter of changing a proportional constant in accordance with the engine speed. CONSTITUTION:When a push button 1 is pressed, since a pulse is generated from an acceleration pulse oscillator 3, a number of the pulses is counted by an up counter 5, and a count value is output as a binary code. This binary code is converted into a hexadecimal digital signal in a decoder circuit 6A, next in a DA convert 7, into an analog value by a prescribed transfer characteristic curve, and after amplification by an amplifier 8, the value is applied to a solenoid 14 of a solenoid proportional valve 9. In this way, a pressure oil flow of the solenoid proportional valve 9 is gradually increased in the beginning to drive a hydraulic cylinder 18 of a boom 17 gradually started and actuated at a fixed speed after a fixed time. Based on an actual rotational speed signal by a rotational speed detector 11A, a proportional constant of the DA converter 7 is adjusted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a boom control device driven by a hydraulic cylinder used in crane trucks, washing trucks, concrete pumping vehicles at high places, cargo trucks and the like.

[0002]

2. Description of the Related Art Conventionally, oil in a hydraulic cylinder that drives a boom is pumped by a hydraulic pump that is driven by an engine of a vehicle, and is sent to the hydraulic cylinder of the boom to raise and lower the boom.

[0003]

[Problems to be Solved by the Invention] Ups and downs of a conventional boom
The turning / stopping operation is performed by a switching valve for opening / closing switching provided in the oil supply passage to the hydraulic cylinder. As a result, fluctuations in the hydraulic pressure of the hydraulic pump directly affect the hydraulic cylinder, and fluctuations in the rotational speed of the pump during engine operation and boom operation affect the hydraulic cylinder, causing the boom to sway and become unstable and unstable. , There was a risk of work. The problem to be solved by the present invention is to solve these conventional problems, and to provide a stable and safe boom drive control device that is not affected by the engine speed and does not swing the boom. is there.

[0004]

SUMMARY OF THE INVENTION An object of the present invention, which has solved the above-mentioned problems, is to provide an acceleration pulse transmitter and a deceleration pulse transmitter which are operated by start and stop pushbuttons for operating a boom, respectively, and the acceleration pulse transmitter. An up counter that counts the pulses that are output, a down counter that counts the pulses that the deceleration pulse oscillator outputs, and a binary code that is output by the up counter and the down counter are added and converted to a hexadecimal output code. A decoding circuit and a DA converter for inputting the hexadecimal output code of each decoding circuit and converting it into an analog signal;
A power amplifier for increasing the analog signal of the DA converter, an electromagnetic proportional valve for electromagnetically controlling the hydraulic cylinder for boom drive by the output of the power amplifier, an engine speed detector for detecting the engine speed, and And an FV converter for converting the rotation speed signal of the engine rotation speed detector into a voltage value and inputting it to the DA converter to change the proportional constant converted by the DA converter so as to be set lower when the engine rotation speed becomes higher. A boom drive control device characterized by the above.

[0005]

In the present invention, in order to operate the boom, when the push button for starting is pressed, the acceleration pulse transmitter continuously generates pulses,
The up counter counts the pulses and outputs the number of pulses as a binary code. The binary code signal is converted into a hexadecimal digital code by a decoding circuit. The hexadecimal digital value output is an integer value that continuously increases from 0. After a certain time (acceleration time), the binary code signal becomes the upper limit value, and thereafter, the constant upper limit value is output from the decoding circuit.
The digital code value output from the decoding circuit is converted into an analog value by the DA converter, and after being amplified by the power amplifier, the solenoid proportional valve is proportionally controlled. As a result, the solenoid proportional valve is gradually opened, and oil is sent to the hydraulic cylinder with a constant opening after the acceleration time. When the stop push button is pressed, the deceleration pulse oscillator / down counter and the decode circuit work to subtract the upper limit binary code value input to the decode circuit, and the hexadecimal digital output from the decode circuit. The value gradually decreases from a constant value. This gradually decreasing hexadecimal digital signal is converted into an analog value by the DA converter, and after being amplified by the power amplifier, it controls the solenoid proportional valve. As a result, the opening of the solenoid proportional valve gradually decreases from open to closed.

As described above, since the opening of the solenoid proportional valve is gradually changed at the time of starting and stopping, the boom is less likely to sway without suddenly operating the hydraulic cylinder. Moreover, for large fluctuations in engine speed,
The rotation speed signal of the engine rotation speed detector is input, converted into a voltage value by the FV converter, and input to the DA converter to change the proportional constant to be converted. If the engine speed increases, the proportional constant is set to a low value so that the DA converter outputs 1 when the engine speed increases.
The hexadecimal digital value becomes low, the opening of the solenoid proportional valve becomes small, and the automatic constant speed operation can be made possible even if the engine speed greatly fluctuates.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a circuit block diagram of an embodiment, FIG. 2 is an explanatory diagram of hydraulic pressure flow of an embodiment, FIG. 3 is an explanatory diagram of applied voltage of a solenoid proportional valve of the embodiment, and FIG. 4 is a pulse generation state of a transmitter of the embodiment. FIG. 5 is an explanatory diagram showing a pulse generation state of another oscillator of the embodiment, and FIG. 6 is a conversion characteristic diagram of the DA converter of the embodiment.

In the figure, reference numeral 1 is a push button for operating the boom to stand up, and 2 is a push button for stopping the stand up, the opening and closing of which are opposite to those of the push button. 3 is an acceleration pulse transmitter, 4 is a deceleration pulse transmitter, 5 is an up counter, 6 is a down counter, and 6A is a binary code output from the up counter 5 and the down counter 6 and added to obtain 1
Decoding circuit for converting to hexadecimal digital code, 7 is D
A converter, 8 is a power amplifier, 9 is a solenoid proportional valve, 1
0 is an adjusting variable resistor for adjusting the oscillation frequencies and pulse widths of the up and down pulse oscillators 3 and 4, 11A is an engine speed detector, 11B is an F / V converter, 1
Reference numeral 2 is an offset voltage adjusting variable resistor for adjusting the drive rise time of the solenoid 14 of the solenoid proportional valve 9, and 13 is an output current detection resistor for detecting the current flowing in the solenoid 14 of the solenoid proportional valve 9 and feeding it back to the power amplifier 8. 1
4 is a solenoid of the solenoid proportional valve 9, 15 is a hydraulic pump, 1
6 is an engine that drives the hydraulic pump, 17 is a boom,
Reference numerals 18 and 19 denote hydraulic cylinders that hoist the boom.

Numerals 21 to 34 are control configurations of the boom 17 which have the same configuration as the control configurations 1 to 14 of the boom 17 standing up. 21 is a push button for starting the fall of the boom 17, 22 is a push button for stopping the fall of the boom 17, 23 is an acceleration pulse transmitter,
24 is a deceleration pulse transmitter, 25 is an up counter, 2
6 is a down counter, 26A is a decoding circuit, 27 is a DA converter, 28 is a power amplifier, 29 is an electromagnetic proportional valve, 30 is a variable resistor for adjusting the oscillation frequency and pulse width, 31 is a missing number, 32 is an offset voltage. A variable resistor for adjustment, 33 is an output current detection resistor, and 34 is a solenoid.

In this embodiment, when the push button 1 is pressed, the accelerating pulse transmitter 3 generates a pulse as shown in FIG. The up counter 5 counts the number of the pulses and outputs the count value as a binary code. The binary code is input to the decoding circuit 6A and converted into a hexadecimal digital signal. The digital signal of the up counter 5 is input to the DA converter 7 and converted into an analog value by the conversion characteristic curve shown in FIG. When the number of pulses is small, a proportional analog value is output, but when it exceeds the upper limit value, the output analog value becomes a constant value thereafter.

This analog value is amplified by the power amplifier 8 and then applied to the solenoid 14 of the solenoid proportional valve 9. The solenoid applied voltage (control voltage) output from the power amplifier 8 is as shown in FIG. That is, in the initial stage when the push button 1 is pressed, the control voltage increases proportionally with time, and the acceleration time is reached. Also, after a certain period of time, it becomes a constant voltage value, which is held. Next, when the reverse push button 2 is pressed, the deceleration pulse oscillator 4 generates a pulse similarly, the down counter 6 counts, and the output of the DA converter 7 gradually decreases from the upper limit value by working in the negative side in the decoding circuit 6A. (See the deceleration time zones in Figures 3 and 4). The control voltage shown in FIG. 3 is the solenoid 14 of the solenoid proportional valve 9.
2, the hydraulic flow rate of the solenoid proportional valve 9 gradually increases in the initial stage as shown in FIG. 2, the hydraulic cylinder 18 of the boom 17 is gradually driven, and a constant speed operation is performed after a certain time.
Also, when the stop operation is performed, the hydraulic cylinder 18 is gradually reduced to stop gently, and the boom 17 does not sway and become unstable, so that the boom can be gently lifted, rotated, and moved up and down. The same applies to the control of the fall motion.

Further, when the engine fluctuates drastically, for example, when the RPM changes from 500 RPM to 3000 RPM, which is 6 times, the RPM signal of the engine RPM detector 11A is changed to FV.
The voltage is converted into a voltage by the converter 11B, and the proportional constant for converting the digital signal having the conversion characteristic of the DA converter 7 into the analog value is adjusted. When the engine speed is high, the proportional constant is set low, and when the engine speed rises drastically, the opening is controlled to be low. Control to become.

As described above, the influence of the engine speed of the hydraulic pump is eliminated by the electromagnetic proportional valve 9 and the engine speed detector 11A and the FV converter 11B which are electromagnetically proportionally controlled, regardless of the hydraulic pressure state of the hydraulic pump 15. The predetermined operation can be surely performed.

[0014]

As described above, according to the present invention, by adopting the configuration of the above characteristics, the influence of the fluctuation of the engine speed of the hydraulic pump driven by the engine is eliminated, and at the time of engine start and engine stop. It became possible to drive a stable and safe boom without shaking the boom.

[Brief description of drawings]

FIG. 1 is a circuit block diagram of an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a hydraulic pressure flow rate according to the embodiment.

FIG. 3 is an explanatory diagram of applied voltage of the solenoid proportional valve according to the embodiment.

FIG. 4 is an explanatory diagram showing a pulse generation state of the oscillator of the embodiment.

FIG. 5 is an explanatory diagram showing a pulse generation state of another oscillator of the embodiment.

FIG. 6 is a conversion characteristic diagram of the DA converter of the embodiment.

[Explanation of symbols]

 1 Push Button 2 Push Button 3 Acceleration Pulse Transmitter 4 Deceleration Pulse Transmitter 5 Up Counter 6 Down Counter 6A Decode Circuit 7 DA Converter 8 Power Amplifier 9 Electromagnetic Proportional Valve 10 Variable Resistor 11A Engine Speed Detector 11B F / V Converter 12 Offset Variable resistor for voltage adjustment 13 Output current detection resistor 14 Solenoid 15 Hydraulic pump 16 Engine 17 Boom 18 Hydraulic cylinder 19 Hydraulic cylinder 21 Push button 22 Push button 23 Acceleration pulse transmitter 24 Deceleration pulse transmitter 25 Up counter 26 Down counter 26A Decoding circuit 27 DA converter 28 Power amplifier 29 Electromagnetic proportional valve 30 Variable resistor 31 Missing number 32 Offset voltage adjusting variable resistor 33 Output current detection resistor 34 Solenoid

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masayuki Moriya 1693-2 Uezu-cho, Kurume-shi, Fukuoka Within Moriya Kogyo Co., Ltd. (72) Inventor Hiroyuki Murakami 1-2-7 Hakataekimae, Hakata-ku, Fukuoka-shi, Fukuoka Stock Company Taiho Bussan (72) Inventor Hirofumi Tanaka 1-2-7 Hakataekimae, Hakata-ku, Fukuoka City, Fukuoka Prefecture Taiho Bussan Co., Ltd.

Claims (1)

[Claims] 1. An acceleration pulse oscillator and a deceleration pulse oscillator which are operated by push-start and stop push-buttons for operating a boom, an up counter for counting the pulses output by the acceleration pulse oscillator, and the deceleration pulse oscillator. A counter for counting the pulses output by the counter, a decode circuit for adding the binary codes output by the up counter and the down counter to convert into a hexadecimal output code, and a hexadecimal output code for each decoding circuit. A DA converter that inputs and converts into an analog signal,
A power amplifier for increasing the analog signal of the DA converter, an electromagnetic proportional valve for electromagnetically controlling the hydraulic cylinder for boom drive by the output of the power amplifier, an engine speed detector for detecting the engine speed, and And an FV converter for converting the rotation speed signal of the engine rotation speed detector into a voltage value and inputting it to the DA converter to change the proportional constant converted by the DA converter so as to be set lower when the engine rotation speed becomes higher. A boom drive control device characterized by the above.