JP4562667B2 - Control device for electromagnetic proportional valve of construction machinery - Google Patents

Description

  The present invention relates to a control device for an electromagnetic proportional valve of a construction machine, and more particularly, to an electromagnetic proportional valve control device suitable for easily switching the output range of an electromagnetic proportional valve used in a hydraulic system in a construction machine such as a hydraulic excavator. .

  Patent Document 1 discloses a conventional control circuit for an electromagnetic device in a construction machine such as a hydraulic excavator. The control circuit of the electromagnetic device described in Patent Document 1 appropriately suppresses the current supplied to the electromagnetic device when the arithmetic processing unit runs away in the control circuit that controls the electromagnetic device having the proportional solenoid unit. Fail safe function is realized.

A basic circuit configuration of the control circuit of the electromagnetic device described in Patent Document 1 will be described. In this control circuit, first, one CPU generates a command signal for each of a plurality of electromagnetic proportional valves. The CPU also uses a multiplexer to select a signal supply channel of the electromagnetic proportional valve to which the generated command signal is to be supplied. The command signal is held as a command voltage in the capacitor in the channel selected by the CPU via the multiplexer. Thereafter, the signal is converted into a pulse signal for turning on / off a switching transistor (FET or the like) via a PWM conversion circuit. Each of the plurality of switching transistors is arranged in each power supply path provided in each of the plurality of electromagnetic proportional valves from one power source. When the corresponding pulse signal is input to the gate of the switching transistor, a driving current corresponding to the pulse signal input to the gate flows through the power supply path (source-drain path). Thus, the drive current generated by the switching transistor based on the pulse signal generated by the conversion is supplied to the electromagnetic proportional valve. The drive current for driving the solenoid proportional valve supplied to each of the plurality of solenoid proportional valves has a one-to-one relationship with the command signal generated by the CPU.
JP 2000-252118 A

  In a construction machine such as a hydraulic excavator, a hydraulic system for operating each of a plurality of mechanical drive units, and each valve operation of a plurality of electromagnetic proportional valves in a hydraulic circuit is controlled by one CPU. As described above, the CPU generates individual command signals corresponding to the currents for controlling the valve operations of the plurality of electromagnetic proportional valves. Each electromagnetic proportional valve includes a proportional solenoid part and a valve part. The output range related to the valve operation of the valve portion in the electromagnetic proportional valve is determined according to the drive current supplied to the proportional solenoid portion, that is, the current flowing through the electromagnetic proportional valve. The output range of each of the plurality of electromagnetic proportional valves in the hydraulic system installed in the construction machine is determined in advance at the design stage according to the model of the construction machine based on the current flowing through the electromagnetic proportional valve. More specifically, the target of the construction machine is determined, and is determined at the stage of incorporating the initial setting software (program).

  By the way, in the actual use mode in construction machines such as current hydraulic excavators, when setting the range of the drive current to the CPU for the output range of the electromagnetic proportional valve in a certain type of construction machine, the hydraulic system is used. It may be necessary to use it for other types of construction machines. In the control circuit of the electromagnetic device of the hydraulic system in the conventional construction machine, when changing the output range of the electromagnetic proportional valve prepared for the construction machine in another model, the CPU, that is, the controller itself is changed, or The only way was to change the constant of the resistance that determines the current inside the controller. However, such a method for changing the output range of the electromagnetic proportional valve is not flexible and is very unusable.

  In view of the above problems, the object of the present invention is to change the output range for each of the plurality of electromagnetic proportional valves provided in the hydraulic system of the construction machine without changing the controller and constants inside the controller. It is an object of the present invention to provide a control device for an electromagnetic proportional valve of a construction machine that can be easily changed by adjusting software without changing.

  In order to achieve the above object, a control apparatus for an electromagnetic proportional valve for a construction machine according to the present invention is configured as follows.

The control device for the electromagnetic proportional valve of the first construction machine (corresponding to claim 1) controls the operation of the construction machine by controlling the operation of each of the plurality of electromagnetic proportional valves of the hydraulic system equipped in the construction machine. It is a control device. This control device is a control program selected according to the electromagnetic proportional valve to be controlled.
An arithmetic processing means (CPU) for reading out and executing the control program from the memory and outputting a command signal for instructing a current to flow through the electromagnetic proportional valve; Conversion means (D / A converter) for converting to a voltage signal, a resistance circuit section that divides the voltage signal and outputs a plurality of voltage signals having different voltage values, and control executed by the arithmetic processing means Follow the program
Based on the selection instruction signal supplied from the processing unit I, selection means for selecting either one of the voltage signals of the plurality of voltage signals output from the resistor circuit (first multiplexer)
And a switching means (second multiplexer) for supplying the voltage signal selected by the selection means to the channel of the electromagnetic proportional valve corresponding to the command signal, a capacitor for holding the voltage signal given from the switching means, and holding in the capacitor Converting means (PW) for converting the applied voltage signal into a pulse signal
M conversion circuit) and switching means (such as an FET) for generating a current to flow through the electromagnetic proportional valve based on the pulse signal.

In the above configuration of the control device in advance by the resistance circuit unit so as to generate a plurality of voltages for dividing effect for one command signal is performed by the arithmetic processing means, an electromagnetic proportional valve to be controlled
Selects the voltage signal corresponding to the output range of the current of the proportional solenoid valve used in the selection means based on the selected control program controls the operation of the hydraulic system of a construction machine to be controlled in accordance with the. The voltage signal corresponding to the command signal output from the arithmetic processing means is determined by a control program executed by the arithmetic processing means. The control program is initially set when a construction machine model to be applied is determined.
In addition, with the above configuration, control is performed at the initial setting stage according to the type of construction machine to be applied.
By changing the program, the current output range of the proportional solenoid valve can be changed.
It can be applied to electromagnetic proportional valves of various construction machinery hydraulic systems.

The control device (corresponding to claim 2 ) of the electromagnetic proportional valve of the second construction machine has the above-described configuration.
Preferably, a resistance element that converts a current flowing through the electromagnetic proportional valve into a voltage is provided, and a voltage obtained by the resistance element is fed back to the conversion means. With this configuration, the current flowing through the electromagnetic proportional valve is stabilized.

The control device (corresponding to claim 3 ) of the electromagnetic proportional valve of the third construction machine has the above configuration,
Preferably, an integration means for integrating the deviation between the voltage signal held in the capacitor and the voltage obtained by the resistance element is provided. This stabilizes the current flowing through the electromagnetic proportional valve.

According to the present invention, in the control system for a hydraulic system, so as to divide the different voltages respectively value command signal of the electromagnetic proportional valve output from the CPU by the resistance circuit unit, prepared in advance further in the initial setting, the control Since the voltage value can be used appropriately by switching with a multiplexer based on the selection command signal by the control program selected according to the target electromagnetic proportional valve , the controller is not changed or the internal constant is not changed. In addition, the current range of the electromagnetic proportional valve can be changed by simply switching the software, which can be adapted to various types of construction machines.

  DESCRIPTION OF EMBODIMENTS Preferred embodiments (examples) of the present invention will be described below with reference to the accompanying drawings.

  A control device for an electromagnetic proportional valve of a construction machine according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 shows an electric circuit configuration of the control device, and FIG. 2 shows signal waveforms of each part of the electric circuit.

FIG. 1 shows a control device of a hydraulic system for causing each of a plurality of mechanical drive units of a construction machine such as a hydraulic excavator to perform its operation. The operation of the mechanical drive is determined by the operating state of the corresponding electromagnetic proportional valve. In FIG. 1, two electromagnetic proportional valves 10-1 to 10-n are shown. In an actual apparatus, there are a plurality (generally n) of electromagnetic proportional valves 10-1 to 10-n , but in the description of this embodiment, two are illustrated for convenience in order to simplify the description. . Each of the plurality of proportional solenoid valves 10-1 to 10-n is supplied with current for driving from the power source (battery) 11 via the corresponding switching transistors (FET, etc.) 12-1 to 12-n. Is done. Current or the current flowing through the electromagnetic proportional valve 10-1 to 10-n for driving a solenoid proportional valves 10-1 to 10-n is a pulsed current determined by on-off operations of the switching transistor. A command signal for controlling the on / off operation of each of the plurality of switching transistors 12-1 to 12-n is given from the CPU 14 of the controller 13 in accordance with the output operation of the corresponding electromagnetic proportional valves 10-1 to 10-n. It is done.

In the control device of the hydraulic system shown in FIG. 1, the valve operation of each of the plurality of electromagnetic proportional valves 10-1 to 10-n in the hydraulic circuit is controlled by one CPU 14. As described above, the CPU 14 generates the individual command signals SIG1 corresponding to the currents for controlling the valve operations of the plurality of electromagnetic proportional valves 10-1 to 10-n. Operating range that is, the output range of the solenoid proportional valves 10-1 to 10-n is set at an initial stage depending on the characteristics of the construction machine to be pre-applied. In other words, the range of the command signal SIG1 provided from the CPU 14 to each of the plurality of electromagnetic proportional valves 10-1 to 10-n is determined in advance by initial setting.

  The control device according to the present embodiment includes the controller 13, and the controller 13 includes a single CPU 14. The CPU 14 includes a memory 15 that contains a control program and the like. The CPU 14 outputs a command signal SIG1 and the like for electromagnetic proportional valve control using a control program and data built in the memory 15. Command signal SIG1 is expressed in digital form. The command signal SIG1 output from the CPU 14 is converted into an analog signal SIG2 by the D / A converter 16. The analog signal SIG2 corresponding to the command signal SIG1 is a voltage signal of 0 to 5 V, for example, generated corresponding to the command signal. An operational amplifier 17 is provided at the next stage on the output side of the D / A converter 16. The operational amplifier 17 is a buffer operational amplifier. The operational amplifier 17 has an amplification factor of 1, and the operational amplifier 17 outputs the voltage signal output from the D / A converter 16 as it is.

  At the subsequent stage of the operational amplifier 17, for example, a resistor circuit section 20 having a bridge circuit-like connection structure using six resistors 21a, 21b, 22a, 22b, 23a, and 23b is provided. In the resistance circuit unit 20, the voltage V1 divided by the two resistors 21a and 21b connected in series between the output terminal of the operational amplifier 17 and the ground unit is divided by the two resistors 22a and 22b that are also connected in series. The compressed voltage V2 and the voltage V3 divided by the two resistors 23a and 23b connected in series are output. The magnitude relationship between the three voltages V1, V2, and V3 is set to, for example, V1 <V2 <V3. Further, the resistance values of the six resistors 21a, 21b, 22a, 22b, 23a, and 23b of the resistance circuit unit 20 are set so that such a voltage magnitude relationship is generated. The branches formed by the resistors 21a and 21b, the branches formed by the resistors 22a and 22b, and the branches formed by the resistors 23a and 23b are formed in a parallel connection relationship. In this embodiment, the number (n) of branches is 3 as an example, but is not limited to this. Any number of divided voltages can be created in any branch.

  The divided voltage generated by the resistor circuit unit 20 is input to the first multiplexer 31 at the next stage.

The first multiplexer 31 is a switching provided from the CPU 14 when the CPU 14 outputs a command signal SIG1 to any one of the n electromagnetic proportional valves 10-1 to 10-n to be used. Receives signal SIG31. The command signal SIG1 output from the CPU 14 is converted into a predetermined voltage signal via the D / A converter 16, the operational amplifier 17, and the resistance circuit unit 20, and then input to the first multiplexer 31 as a voltage signal. The The first multiplexer 31 adjusts the plurality of voltages V1, V2, and V3 input from the resistance circuit unit 20 to the electromagnetic proportional valve to be used among the electromagnetic proportional valves 10-1 to 10-n, and the switching signal SIG3 1 Select based on, and output. The voltage signal SIG4 output from the first multiplexer 31 is input to the second multiplexer 32.

The second multiplexer 32 receives the voltage signal SIG 4 output from the first multiplexer 31 and, based on the switching signal SIG 32 supplied from the CPU 14, capacitors 33-1 to 33 in each channel of the corresponding electromagnetic proportional valve. -N is charged. The capacitors 33-1 to 33-n of each channel selected by the second multiplexer 32 hold a predetermined voltage (SIG4) based on the command signal SIG1, and the held voltage (SIG4) is the operational amplifier 34 in the subsequent stage. -1 through 34-n.

  The voltage signal SIG5 output from the operational amplifiers 34-1 to 34-n is then input to the integrating circuits 35-1 to 35-n. In the integration circuits 35-1 to 35 -n, the voltage signals SIG 5 input from the operational amplifiers 34-1 to 34 -n and the resistors 36-1 to 36 -n of the electromagnetic proportional valves 10-1 to 10 -n are taken out. The difference (deviation) from the fed back voltage signal is integrated, and the voltage signal SIG6 generated by this integration processing is output. The voltage signal SIG6 obtained by the integration calculation in the integration circuits 35-1 to 35-n is input to the PWM conversion circuits 37-1 to 37-n.

  A dither waveform signal SIG7 is further input from the dither waveform oscillation circuit 38 to the PWM conversion circuits 37-1 to 37-n. The PWM conversion circuits 37-1 to 37-n convert the voltage signal SIG6 supplied from the integration circuits 35-1 to 35-n into a pulse signal SIG8 based on the dither waveform signal SIG7, and output the pulse signal SIG8. Output as a signal. The output signal SIG8 of the PWM conversion circuits 37-1 to 37-n is input to the gates of the switching transistors 12-1 to 12-n, and turns on / off the operations of the switching transistors 12-1 to 12-n. . As a result, the current flowing between the source and drain of the switching transistors 12-1 to 12-n is converted into a substantially pulse shape. The switching transistors 12-1 to 12-n turn on / off the current flowing through the electromagnetic proportional valves 10-1 to 10-n, and supply the current corresponding to the command voltage SIG1 output from the CPU 14 to the electromagnetic proportional valve 10-1. -10-n. The substantially pulsed currents I1 to In supplied from the switching transistors 12-1 to 12-n flow into the input terminal a of the electromagnetic proportional valves 10-1 to 10-n and flow out from the output terminal b. The current flowing out from the output terminal b of the electromagnetic proportional valves 10-1 to 10-n flows through the resistors 36-1 to 36-n described above. The resistors 36-1 to 36-n convert the current flowing through the electromagnetic proportional valves 10-1 to 10-n into a voltage and feed back the voltage signal to the integrating circuits 35-1 to 35-n. By providing such a feedback circuit for each of the plurality of proportional solenoid valves 10-1 to 10-n, a constant drive current corresponding to the command signal SIG1 flows in the proportional solenoid valves 10-1 to 10-n. Control is performed.

According to the configuration of the electric circuit of the control apparatus, converts the command signal SIG1 output from the CPU 14, the resistor circuit 20 by dividing obtained was plurality of voltage signals V1~V3 (or V1~V _N) Then, the first multiplexer 31 selects and takes out one of the voltage signals V1 to V3, and controls the currents I1 to In flowing through the corresponding predetermined electromagnetic proportional valves 10-1 to 10-n based on the taken out voltage signal. To do. Assuming that the current that flows when the voltage V1 is selected is I1, the current that flows when the voltage V2 is selected is I2, and the current that flows when the voltage V3 is selected is I3, the magnitude relationship between the currents I1, I2, and I3 is I1 < The relationship of I2 <I3 is established. The voltage V1, V2, V3 is switched according to the type of the solenoid proportional valves 10-1 to 10-n used, and the output range of the solenoid proportional valve most suitable for the construction machine to be applied, that is, the current flowing through the solenoid proportional valve A control range can be selected.

  As described above, the first multiplexer 31 can arbitrarily select a plurality of voltages V1 to V3 created by the voltage dividing action in the resistance circuit unit 20, and the electromagnetics whose operation is to be controlled according to the selected voltage value. The range of the current flowing through the proportional valve can be easily switched.

  According to the above-described embodiment, the command signal SIG1 from the CPU 14 of the control device of the hydraulic system can be divided into voltages having different values by the resistance circuit unit 20 and switched by the first multiplexer 31 to be used as appropriate. Therefore, it is possible to adapt to various types of construction machines by changing the current range of the solenoid proportional valve by simply switching the software without changing the controller 13 or changing the internal constant elements.

  The configurations and the like described in the above embodiments are merely schematically shown to such an extent that the present invention can be understood and implemented. Therefore, the present invention is not limited to the described embodiments and is not limited to patents. Various modifications can be made without departing from the scope of the technical idea shown in the claims.

  The present invention is applied to a hydraulic system of a construction machine such as a hydraulic excavator and is used to change the output range of a plurality of electromagnetic proportional valves.

It is a circuit block diagram of the electric circuit which concerns on embodiment of the control apparatus of the electromagnetic proportional valve of the construction machine of this invention. The signal waveform of each part of an electric circuit is shown. It is a waveform chart which shows the signal waveform of each circuit part of the electric circuit shown in FIG.

Explanation of symbols

10-1 to 10-n Proportional solenoid valve 11 Power supply 12-1 to 12-n Switching transistor 13 Controller 14 CPU
DESCRIPTION OF SYMBOLS 15 Memory 16 D / A converter 20 Resistance circuit part 31 1st multiplexer 32 2nd multiplexer 33-1 to 33-n Capacitor 35-1 to 35-n Integration circuit 37-1 to 37-n PWM conversion circuit 38 Dither waveform circuit

Claims (3)

In the control device for controlling the operation of the construction machine by controlling the operation of each of the plurality of electromagnetic proportional valves of the hydraulic system equipped in the construction machine,
It has a memory to store the control program selected according to the electromagnetic proportional valve to be controlled
Arithmetic processing means for reading out and executing the control program from the memory and outputting a command signal for instructing a current to flow through the electromagnetic proportional valve;
Conversion means for converting the command signal into a voltage signal;
A resistance circuit that divides the voltage signal and outputs a plurality of voltage signals having different voltage values ;
Based on the selection instruction signal given from the arithmetic processing means according to the control program executed by the arithmetic processing means, one of the plurality of voltage signals output from the resistance circuit unit is selected. A selection means;
Switching means for supplying the voltage signal selected by the selection means to a channel of the electromagnetic proportional valve corresponding to the command signal;
A capacitor for holding the voltage signal given from the switching means;
Conversion means for converting the voltage signal held in the capacitor into a pulse signal;
Switching means for generating the current to flow through the electromagnetic proportional valve based on the pulse signal;
A control device for an electromagnetic proportional valve of a construction machine. Wherein comprises a resistive element for converting the current flowing to the proportional solenoid valve to the voltage, proportional solenoid valve for a construction machine according to claim 1 Symbol mounting, characterized in that the feedback of the voltage obtained by the resistor element to the converting means Control device. 3. The control device for an electromagnetic proportional valve for a construction machine according to claim 2, further comprising integrating means for integrating a deviation between the voltage signal held in the capacitor and a voltage obtained by the resistance element.

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