JPH0534018Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field This invention relates to an electric circuit for controlling a variable pump regulator in a relief circuit for a working machine installed in a construction machine.

BACKGROUND ART FIG. 2 is a side view of a hydraulic excavator in which a crusher 2, which is a working machine, is attached to the tip of a working attachment 1. In the figure, 3 is a lower traveling body, 4 is an upper revolving body, and 5 is a hydraulic actuator of the crusher 2. FIG. 3 is a relief circuit diagram for a working machine equipped with a conventional electric circuit 6. As shown in FIG. In the figure, 7
1 is a controller in the electric circuit 6, 8 is a pressure switch, 9 is a directional control valve of the hydraulic actuator 5 for the work machine, 10 and 11 are leaf valves, 12 is a remote control valve, 13 and 14 are variable pumps, 1
5 is a pilot pump, 16 and 16' are regulators for variable pumps 14 and 13, respectively, 17 is an electromagnetic proportional valve for regulators 16 and 16', and 18 is a switching valve for controlling various hydraulic actuators (excluding hydraulic actuator 5 for work equipment). Group 19 is a pilot opening/closing valve which causes the switching valve group 18 to shut off the center bypass oil path return side only when the operating lever L of the remote control valve 12 is operated alone; 29 is a hydraulic actuator 5 when the remote control valve 12 is operated; This is the main pressure take-off valve for taking out the pressure oil supplied to the Here, when the operating lever L of the remote control valve 12 is operated in either the left or right direction, the pilot valve 20 or 21 is switched. Pressure oil from the pilot pump 15 flows through oil lines 22, 2.
3. Acts on the pilot pressure receiving portion 26 or 27 of the directional control valve 9 via the pilot valve 20 or 21 and the oil passage 24 or 25. Since the directional control valve 9 is switched to the A position or the B position, the variable pump 1
4, the main discharge pressure oil is supplied to the oil passages 28, 30, the check valve 53, the oil passages 54, 55, 56, 57, the main pressure take-off valve 29, the oil passages 58, 59, the check valve 31, and the directional control valve 9. It is supplied to the hydraulic actuator 5 through the position or the position B. As a result, the hydraulic actuator 5 is operated, so that the crusher 2 can be used. Note that when an overload is applied to the hydraulic actuator 5 while the crusher 2 is in use, the high-pressure oil is relieved into the oil tank 32 by the relief valve 10 or 11. On the other hand, the regulators 16, 16' of the variable pumps 14, 13 have first input valves 33, 33', second input valves 33, 33',
Input valves 34, 34', control valves 35, 35', servo piston valves 36, 36', etc. are provided.
Therefore, _{the variable} pump 14,
13 can be applied with respective autogenous pressure. Also, the port portion of the second input valve 34, 34'
By applying a pilot pressure such as a negative control pressure to P ₁ , P _n , P ₁ ', and P _n ', the discharge flow rate of the variable pumps 14 and 13 can be restricted.

Next, the configuration of a relief circuit including a conventional electric circuit 6 will be described with reference to FIG. A pressure switch 8 is provided for the pressure oil supply oil passage that communicates the directional control valve 9 for the hydraulic actuator 5 of the work equipment 2 with the main pressure take-off valve 29, and one of the two-way contacts of the pressure switch 8 is connected to one contact 37. The pressure introduction part C was connected to the pressure oil supply passages 58-59, and the other contact 38 was grounded. Further, the base contact 39 of the pressure switch 8 and the electromagnetic proportional valve 17 of the regulator 16, 16' are connected via the controller 7. Then, during operation of the hydraulic actuator 5 for the working machine 2, the pressure switch 8 is switched by the hydraulic pressure in the pressure oil supply oil passages 58-59 around the time when the relief valve 10 or 11 for the hydraulic actuator 5 is relieved, and signal to controller 7
In addition, the controller 7
The constant current output from the regulator 16,1
The electromagnetic proportional valve 1 of 6' is configured to be energized.

Next, the functions of the relief circuit equipped with the conventional electric circuit 6 will be described. When the hydraulic actuator 5 for the work equipment 2 is operated and an overload is applied to the hydraulic actuator 5, the oil pressure in the pressure oil supply side oil passages 58-59 increases, and at the same time,
The relief valves 10, 11 reach a point of relief. Therefore, the oil pressure in the oil passages 58-59 acts on the pressure introduction portion C of the pressure switch 8 through the oil passage 40. The pressure switch 8 is operated to ground the electric line 41 leading from the pressure switch 8 to the controller 7 via the pressure switch 8. Therefore, the electrical circuit grounding signal mentioned above is input to the controller 7. Based on the circuit grounding signal, a constant current output from the controller 7 passes through the circuit 42 to the electromagnetic proportional valve 1 of the regulator 16, 16'.
7 solenoid 43 is energized. Solenoid proportional valve 1
7 is switched, so the pilot pressure from the pilot pump 15 passes through the oil passages 22 and 44 and the electromagnetic proportional valve 17, and acts on the port portions P _f and P _f ' of the first input valves 33 and 33', respectively. . As a result, the swash plate tilt angle of the variable pump 14 is adjusted, and the pump discharge flow rate is reduced. Therefore, the amount of relief oil when the relief valve 10 or 11 of the hydraulic actuator 5 for the working machine 2 is relieved is also reduced. In other words, the energy loss of the hydraulic oil due to relief and the relief noise are reduced, resulting in an energy saving effect and helping to prevent noise pollution.

Problems that the invention aims to solve Hydraulic excavators sometimes have a special working device such as a crusher attached to the tip of their working attachment. In that case, the hydraulic excavator is equipped with a controller to operate a mechatronic function, and when the hydraulic actuator for the working machine is relieved, the pump discharge flow rate is reduced to reduce energy loss and relief noise. However, the mechatronic function provided by the above-mentioned controller is sufficiently stable for maintenance purposes, so failures may occur. Therefore, if the controller breaks down while using the working machine, energy loss and relief noise increase.

This invention solves the above problem, and when the controller fails, by operating the mechatronic release switch in redundant mode, a constant current equivalent to that during mechatronic operation can be passed through the variable pump regulator. The purpose of the present invention is to provide an electric circuit for controlling a regulator.

Measures to solve the problem: (a) A mechatronic release switch is interposed in the electrical circuit that communicates the control roller and the electromagnetic proportional valve for the regulator; , a resistor is provided in parallel in the electrical path communicating with the release switch, and a relay is provided in the electrical path communicating between one of the registers and the base contact of the pressure switch, c. the release switch is placed in the mechatronic release position. It is set so that the output signal from the controller can be cut off when the switch is operated, and a constant current equivalent to that during mechatronic operation before the release switch is operated is applied to the electromagnetic proportional valve of the regulator through the relay, register, and release switch. It was configured to be able to be distributed.

Operation (a) When the release switch is operated to the mechatronic function activation side position, the mechatronic function is activated in the same manner as in the prior art.

(b) When the release switch is switched to the mechatronic release position, the output signal from the controller is cut off by the release switch.

C. A resistor installed in parallel with the electrical circuit that communicates the base contact of the pressure switch and the release switch is such that when the relay closes the electrical circuit, the current flowing from the power supply to the regulator electromagnetic proportional valve is equivalent to that when the mechatronic operation is activated. is set to be.

D. When the release switch is switched to the mechatronic release position, a constant current flows through the relay, register, and release switch to the electromagnetic proportional valve of the regulator when the hydraulic actuator for the work machine is relieved. Therefore, if the release switch is operated immediately when the controller malfunctions, the pump and flow rate can be reduced when the hydraulic actuator for the working machine is relieved.

Embodiments Hereinafter, embodiments of this invention will be described in detail based on the drawings. FIG. 1 is a relief circuit diagram for a working machine equipped with an electric circuit 45 according to this invention. In the figure, the same reference numerals are given to the same components as in the prior art. 46 is a controller in the electric circuit 45, 47 is a release switch for mechatronics, 48 and 49 are registers, and 50
is a relay, 51 is a diode, and 52 is a power supply.

Next, the configuration of the electric circuit 45 according to this invention will be described with reference to FIG. A mechatronic release switch 47 is interposed in the electrical path communicating the controller 46 and the electromagnetic proportional valve 17 for the regulators 16, 16'. In addition, a resistor 4 is connected to the electrical path that communicates the base contact 39 of the pressure switch 8 and the release switch 47.
8 and 49 in parallel, and one register 4
A relay 50 is provided in an electric path communicating between the pressure switch 8 and the pressure switch 8 base contact 39. When the release switch 47 is switched to the mechatronic release position (a position in which contacts N and H, and N' and H' are closed in conjunction with each other), the output signal from the controller 46 is set to be cut off, and the relay 50 , register 48
And 49, a constant current equivalent to that during mechatronic operation before switching the release switch is configured to flow to the electromagnetic proportional valve 17 of the regulator 16 through the release switch 47.

Next, the functions of the electrical circuit 45 according to the invention will be described. When the release switch 47 is operated to the mechatronic function activation side position as shown in Fig. 1 (the position where contacts N and H and N' and H' are closed in conjunction), the mechatronic function is activated as in the prior art. be done. When the release switch 47 is switched to the mechatronic release position, the output signal from the controller 46 is cut off by the release switch 47. On the other hand, when the relay 50 closes the electrical circuit, the resistors 48 and 49, which are interposed in parallel with the electrical circuit that communicates the base contact 39 of the pressure switch 8 and the release switch 47, are connected to the electromagnetic circuit for the regulators 16 and 16' from the power source 52. The current value flowing through the proportional valve 17 is set to be equal to that during mechatronic operation. Work equipment 2
If the controller 46 breaks down while operating the hydraulic actuator 5 for work, switch the release switch 47 to the mechatronic release position.If an overload is applied to the hydraulic actuator 5 during work, the pump Since the oil pressure in the discharge oil passage 30 increases, the pressure switch 8 is operated, and the base contact 39 of the pressure switch 8 is grounded. The relay 50 then closes that circuit, so the current from the power source 52 flows through the resistors 48, 49 and the release switch 4.
7, the solenoid 43 of the electromagnetic proportional valve 17 is energized. In this case, the resistors 48 and 49 arranged in parallel in the electric circuit are set to flow a constant current to the solenoid 43 equivalent to that during the mechatronic operation before the release switch 47 is switched. Therefore, the electromagnetic proportional valve 17 can be switched by the constant current.

Therefore, if the release switch 47 is operated immediately when the controller 46 breaks down, the pump discharge flow rate can be reduced when the hydraulic actuator 5 for the working machine 2 is relieved.

Effects of the invention In the electric circuit for controlling the regulator according to this invention, when the controller is malfunctioning while operating the hydraulic actuator for the working machine and performing work, the release switch is switched to the mechatronic release position. When an overload is applied to the hydraulic actuator during operation, the pressure switch is activated, and a constant current flows through the resistor, release switch, etc. to the electromagnetic proportional valve of the regulator. Thereby, the pump discharge flow rate can be reduced when the hydraulic actuator for a working machine is relieved, and energy loss and relief noise can be reduced.

Therefore, the construction machine equipped with the regulator control electric circuit according to this invention can function as a redundant mode when the controller fails.

[Brief explanation of the drawing]

Fig. 1 is a relief circuit diagram for a working machine equipped with an electric circuit for controlling the regulator according to this invention, Fig. 2 is a side view of a hydraulic excavator with the working machine attached;
FIG. 3 is a relief circuit diagram for a working machine equipped with a conventional electric circuit. 2... Crusher (work machine), 5... Hydraulic actuator, 6, 45... Electric circuit, 7, 46... Controller, 8... Pressure switch, 13, 14...
...Variable pump, 15...Pilot pump, 1
6, 16'...Regulator, 17...Solenoid proportional valve, 29...Main pressure take-off valve, 47...Release switch, 48, 49...Register, 50...
relay.

Claims (1)

[Scope of utility model registration request] A pressure switch is installed in the pressure oil supply line that communicates the directional control valve of the work equipment attached to the work attachment of the construction machine and the main pressure take-off valve, and the base contact of the pressure switch and the variable pump Connecting the electromagnetic proportional valve of the regulator via a controller, and switching the pressure switch by the hydraulic pressure in the pressure oil supply oil path around the time when the relief valve for the hydraulic actuator relieves during the operation of the hydraulic actuator for the work machine, and energizing the electromagnetic proportional valve of the regulator with a constant current output from the controller based on the switching operation signal,
In the relief circuit designed to reduce the pump discharge flow rate, a mechatronic release switch is interposed in the electrical line communicating between the controller and the electromagnetic proportional valve, and a mechatronic release switch is provided in the electrical line communicating between the base contact of the pressure switch and the release switch. Resistors are interposed in parallel, and a relay is provided in the electrical path that communicates one of the registers with the pressure switch base point, and the output signal from the controller is cut off when the release switch is switched to the mechatronic release position. The regulator is characterized in that it is configured to allow a constant current to flow through the relay, register, and release switch to the electromagnetic proportional valve of the regulator, which is equivalent to that during mechatronic operation before switching the release switch. Electrical circuit for control.