JPH0657787A - Flow rate control device for crusher - Google Patents

Abstract

PURPOSE:To improve responsiveness in work for an oil-hydraulic shovel by a method wherein electric current values to be outputted in accordance with signal voltage from a variable control part that changes the signal voltage in raising and lowering are stored in a memory, and pilot pressure is applied to a regulator of a variable pump through a solenoid operated proportional control valve. CONSTITUTION:A variable resistance control part 82 that enables selective operations to be executed by raising or lowering signal voltage is provided against a controller 3'. Specified electric current value to be outputted in accordance with the signal voltage from the variable resistance control part 82 is stored in a memory 83 of the controller 3'. A solenoid operated proportional pressure reducing valve 84 for deducing pilot pressure to be applied to a regulator 26 of a first pump 24 is provided. In operating a crusher 7 at a specified operating flow rate N, the variable resistance control part 82 is made to be operated at the specified N position, and thereby the signal voltage is inputted into the controller 3'. Furthermore, a command electric current value signal is outputted, based on signals from the variable resistance control part 82 and a pressure switch 85, from the controller 3' to a solenoid 86 of the solenoid operated proportional pressure reducing valve 84.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crusher mounted on a work attachment such as a construction machine or a work vehicle (specifically, a hydraulic crusher, generally called a hydraulic breaker), a crusher, etc. The present invention relates to a flow control device for a special work machine.

[0002]

2. Description of the Related Art FIG. 2 is a side view of a hydraulic excavator.
In the figure, 1 is a lower traveling structure, 2 is an upper revolving structure, 3 is a controller mounted on the upper revolving structure 2, 4 is a work attachment mounted on the front part of the upper revolving structure 2,
5 is a boom of the work attachment 4, 6 is an arm, 7 is a crusher, 8 is a boom cylinder of various hydraulic actuators equipped on a hydraulic excavator, 9 is an arm cylinder, 10 is a bucket cylinder, 11 is a swing motor, 12
L and 12R are left and right traveling motors. FIG. 3 is a circuit diagram of a main part of a conventional technique installed in the hydraulic excavator in FIG. In the figure, 13 is a right pilot switching valve for traveling,
Reference numeral 14 is a boom pilot switching valve, 15 is a bucket pilot switching valve, 16 is a center bypass oil passage, 17 is a cut valve arranged on the outlet side of the center bypass oil passage 16, 1
8 is a low pressure relief valve for setting negative control pressure, 19 is a throttle part, 20 is a crusher pilot switching valve, 21 is a pressure oil supply valve for the crusher (20), 22 is a hydraulic remote control valve for the crusher, and 23 is running. Linear valves, 24 and 25 are variable pumps, first and second pumps, regulators of the first pump 24, P
i is a pilot port for controlling the negative flow rate of the regulator 26, Pm is a pilot port for limiting the maximum flow rate, 27 is an electromagnetic switching valve for cutting the maximum flow rate, 28 is a pilot pump which is a pilot pressure hydraulic source, 29 is an oil tank, and 30 is work. A mode changeover switch, 31 is a control motor such as a stepping motor, 32 is a governor of the engine 33, and 89 is a selection switch for switching to a contact point when the crusher 7 is detached and replaced by a crusher (not shown).

Next, the structure of the circuit of the prior art will be described with reference to FIGS. A work attachment 4 is provided on the front part of the upper swing body 2 of the hydraulic excavator, a crusher 7 is attached to the tip of the work attachment (4), and as a detection means for detecting the operation / non-operation of the crusher 7. It is equipped with a pressure switch 34. Further, the engine (33) rotation speed and the pump (first pump 24) maximum discharge flow rate can be adjusted via the controller 3 by operating the work mode changeover switch 30. Further, the negative flow rate control is performed by causing the negative control pressure on the outlet side of the center bypass oil passage (16) to act on the pilot port Pi of the regulator 26 for the first pump 24.

Next, the operation of the prior art circuit will be described. In the hydraulic excavator, a work mode changeover switch 30 is provided for the controller 3 in order to select the work amount and fuel consumption according to the corresponding work content. That is, by selecting a required work mode, the rotation speed of the engine 33 is selected from among the H mode (medium and high speed rotation for heavy load), S mode (medium and low speed rotation for normal load), and FC (micro speed rotation). You can choose either. Since the hydraulic circuit shown in FIG. 3 controls the negative flow rate, when the engine 33 of the hydraulic excavator is rotating and various hydraulic actuators (including the crusher 7) are not operated at all, the center bypass oil passage 16 outlet Side low pressure relief valve 18
The negative control pressure rises on the upstream side of. The negative control pressure on the upstream side of the low-pressure relief valve 18 is the pipe line 35, the throttle portion 36,
It acts on the pilot port Pi via the pipe line 37. The negative control pressure increased as described above causes the pilot port Pi
As a result, the regulator 26 operates and the tilting amount of the swash plate of the pump is adjusted, so that the discharge flow rate of the first pump 24 is reduced and energy can be saved.

Next, the case where the crusher 7 is used to perform the crushing work will be described. (Here, the stop valve 90 shown in FIG. 3 is closed in advance. Due to the structure and maintenance of the crusher 7, other hydraulic actuators such as the boom cylinder 8 and the bucket shown in FIG. It is much less than the cylinder 10).
Therefore, the work mode switching switch 30 is selected as the FC mode. The FC mode selection signal is input to the controller 3. The controller 3 makes a determination based on the FC mode selection signal, and outputs an engine slow speed rotation command signal to the control motor 31. Since the control motor 31 rotates to operate the governor 32, the engine 33 rotates at a very low speed. Next, in order to operate the crusher 7, the hydraulic remote control valve 22 is operated (stepped on) in the direction of arrow a. The pilot primary pressure from the pilot pump 28 is
9, the pilot valve 40, the pilot secondary pressure derived from the pilot valve 40 passes through the pipe line 41 and the oil line 42,
Pilot pressure receiving portion 4 of crusher pilot switching valve 20
Act on 3. At the same time, the pilot secondary pressure branched from the oil passage 42 (hereinafter, the pilot secondary pressure and the pilot primary pressure are simply referred to as pilot pressure) is the oil passage 44, the shuttle valve 45, the oil passage 46, the pipe passages 47, 48, and the oil. It acts on the pilot pressure receiving portion 51 of the on-off valve 50 via the passage 49.
Simultaneously with the above, the pilot pressure branched from the oil passage 46 acts on the pilot pressure receiving portion 57 of the cut valve 17 via the pipe 52, the shuttle valve 53, the pipe 54, the shuttle valve 55, and the pipe 56. Simultaneously with the above, the pilot pressure branched from the pipe line 47 acts on the pipe line 58 and the pressure switch 34, and the pilot pressure signal is input to the controller 3 through the electric line 59, the selection switch 89, and the electric line 59 ′. The controller 3 makes a determination based on the pilot pressure signal and outputs a switching command signal to the solenoid 60 of the electromagnetic switching valve 27. The electromagnetic switching valve 27 switches from the tank communication oil passage position B to the open oil passage position C. The pilot pressure from the pilot pump 28 is branched in the pipe line 38, and the pipe lines 61 and 62, the throttle portion 63, the pipe line 64, and the electromagnetic switching valve 27.
It acts on the pilot port Pm via the open oil passage position C and the pipe 65. Thereby, the maximum discharge flow rate of the first pump 24 is limited.

When the hydraulic remote control valve 22 is operated as described above, the pilot pressure is derived from the pilot valve 40, so that the cut valve 17 is at the shutoff oil passage position and the on-off valve 5 is closed.
0 is at the open oil passage position, and the pilot switching valve for the crusher 2
0 switches to each of the two positions. Therefore, the limited discharge flow rate from the first pump 24 is controlled by the pipelines 66, 67, the e position of the straight travel valve 23, the right pilot switching valve 13 for travel.
Neutral position, oil passages 68, 69, check valve 70, oil passage 7
1, 72, 73, the conduit 74, the logic valve 75 are pushed open, and the oil conduit 76, the conduit 77, the check valve 78, the oil conduit 79,
It is supplied to the crusher 7 through the two positions of the crusher pilot switching valve 20, the oil passage 80, and the pipe 81. As a result, the crusher 7 operates and the crushing work can be performed without any trouble.

Next, the case where the crusher 7 is removed and replaced with a crusher (not shown) to perform the crushing work will be described. Here, the stop valve 90 is opened in advance, the rotation speed of the engine 33 is set to the H mode (medium and high speed rotation for heavy load), and the selection switch 89 is switched to the C contact.
Even if the hydraulic remote control valve 22 is operated to start the crushing work,
By switching the selection switch 89 to the high contact, the controller 3 outputs an off command signal to the solenoid 60. Since the electromagnetic switching side 27 maintains the tank communication oil passage position B, the pilot pressure does not act on the pilot port Pm when the crusher is used. So the first pump 2
4, it is possible to supply a large amount of pump flow rate to the crusher. When the operation of all hydraulic actuators including the crusher is stopped, the low pressure relief valve 18
The negative control pressure on the upstream side is the pipeline 35, the throttle portion 36, the pipeline 3
7 and acts on the pilot port Pi. Since the regulator 26 operates and the discharge flow rate of the first pump 24 decreases, it is possible to save energy.

[0008]

If the predetermined operating flow rates of the various crushers and crushers mounted on the hydraulic excavator are only two types, the driver can respond by operating the work mode changeover switch, the selection switch, or the like. Although it is possible, even if it is desired to replace the various kinds of crushers and the like, the pump discharge flow rate cannot be adjusted and set. Further, in the prior art, when using a crusher with a low operating flow rate, the engine rotation is selected to be in FC mode (slow speed rotation), and when the crusher is stopped during work and other hydraulic actuators are moved to H mode (medium / high speed rotation). ). The engine speed change sound was not only unpleasant to the ear, but also caused mental discomfort and fatigue. The present invention aims to solve the above problems.

[0009]

In the flow rate control device of the present invention, a variable resistance operating section for changing and selecting a signal voltage is provided for the controller, and a memory of the controller is provided with the variable resistance operating section. A predetermined proportional current value to be output according to the signal voltage is stored, and an electromagnetic proportional pressure reducing valve is provided to derive the pilot pressure to act on the regulator of the variable pump, and the variable resistance operating unit is adjusted and operated. When the crusher is activated, the controller makes a judgment based on the signals from the variable resistance operating unit and the crusher operation detection means, and the controller outputs a command current value signal to the electromagnetic proportional pressure reducing valve. By applying a pilot pressure to the regulator of the variable pump via the, the pump discharge flow rate is controlled.

[0010]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a circuit diagram of essential parts showing a flow rate control device of the present invention. In the figure, the same reference numerals are given to those using the same constituent elements as those in the prior art. Next, the configuration of the flow rate control device of the present invention will be described with reference to FIG. In the present invention, a variable resistance operating unit 82 that can be selected and operated by changing the signal voltage up and down is provided for the controller 3 ′, and the memory (ROM) 83 of the controller 3 ′ is provided with the signal voltage from the variable resistance operating unit 82. A predetermined proportional electric current value to be output according to the above is stored, and an electromagnetic proportional pressure reducing valve 84 is arranged to derive a pilot pressure to act on the regulator 26 of the first pump 24, and the variable resistance operating portion 82 is adjusted. Then, when the crusher 7 is operated, the variable resistance operating unit 82 and the pressure switch 8 which is the crusher operation detecting means.
The controller 3'determines based on the signal from the controller 5, and the controller 3'determines the solenoid 8 of the electromagnetic proportional pressure reducing valve 84.
6 outputs a command current value signal to the regulator 26 of the first pump 24 via the electromagnetic proportional pressure reducing valve 84.
By applying a pilot pressure to, the pump discharge flow rate was controlled.

Next, the operation of the flow rate control device of the present invention will be described. The variable resistance operating unit 82 in the present invention has an operating position set so that a predetermined operating flow rate, for example, M, N, T, K of various crushers, crushers, etc. to which the hydraulic excavator is replaced can be selected. There is. Further, when the work is performed by using the above various crushers and crushers, the work mode selector switch 30 is always set to the H mode. Here, as a typical example, the case of operating the crusher 7 will be described, but the predetermined operating flow rate of the crusher 7 is N.
When the variable resistance operating unit 82 is operated to the set N position,
The signal voltage is input to the controller 3 '. Then, the hydraulic remote control valve 22 is operated (stepped on) in the direction of arrow a. The pilot pump primary pressure from the pilot pump 28 is the pipelines 38 and 39, the pilot valve 40, and the pilot secondary pressure derived from the pilot valve 40 is through the pipelines 87 and 88, the shuttle valve 91, and the pipeline 92, It acts on the pressure switch 85. The crusher operation detection signal from the pressure switch 85 is input to the controller 3 ′. The controller 3'determines based on the signals from the variable resistance operating unit 82 and the pressure switch 85, and the controller 3 '
Outputs a command current value signal to the solenoid 86 of the electromagnetic proportional pressure reducing valve 84. Depending on the command current value signal,
The electromagnetic proportional pressure reducing valve 84 performs an adjusting operation. The pilot pressure from the pilot pump 28 is branched in the pipe 38, and the pipes 61 and 62, the throttle portion 63, the pipe 64, and the electromagnetic proportional pressure reducing valve 8 are branched.
4, it acts on the pilot port Pm of the regulator 26 via the pipe 65. At the same time, the pilot secondary pressure derived from the pilot valve 40 branches in the pipe line 87, and acts on the pilot pressure receiving portion 43 of the crusher pilot switching valve 20 via the pipe lines 41 ′ and 42. The pilot switching valve 20 switches from the neutral position to the two position. As a result, the crusher 7 operates without trouble at the limited predetermined flow rate N from the first pump 24.

As described above, when the hydraulic excavator works by replacing various crushers, crushers, etc. having different predetermined operating flow rates, the work mode changeover switch 3
If the variable resistance operating portion 82 is selected and operated at a predetermined flow rate position (any one of M, N, T, and K positions, or an intermediate position between them) while 0 is still selected as the H mode, Therefore, the maximum discharge flow rate of the first pump 24 can be adjusted to a predetermined predetermined flow rate.

[0013]

In the hydraulic excavator of the prior art, the pump discharge flow rate cannot be set to a predetermined flow rate when the work is performed by replacing a plurality of various types of crushers and crushers. Further, in the prior art, when using a crusher with a low operation flow rate, the engine speed is lowered when the crusher is operated and increased when it is not operated, so the noise of engine rotation change is audible. It was
However, in the flow rate control device of the present invention, it is provided for the variable resistance operating unit controller that can select and operate by changing the signal voltage up and down, and the memory of the controller outputs a predetermined value according to the signal voltage from the variable resistance operating unit. An electromagnetic proportional pressure reducing valve is provided to store the current value of the above and to derive the pilot pressure applied to the regulator of the variable pump. Therefore, when the crusher is operated by adjusting the variable resistance operating unit, the controller makes a judgment based on the signals from the variable resistance operating unit and the crusher operation detecting means,
By outputting a command current value signal from the controller to the electromagnetic proportional pressure reducing valve and causing the pilot pressure to act on the regulator of the variable pump via the electromagnetic proportional pressure reducing valve, the pump discharge flow rate can be controlled. That is, when excavators work by exchanging various crushers, crushers, etc. having different predetermined operation flow rates,
With the work mode switch still selected in H mode,
If the variable resistance operating unit is selected at the required flow rate position, the maximum discharge flow rate of the variable pump can be automatically adjusted to the required predetermined flow rate. Therefore, since the flow controllability corresponding to various crushers, crushers, etc. is improved, workability of the hydraulic excavator can be improved. Further, when the hydraulic excavator equipped with the flow rate control device of the present invention carries out the crushing work, the engine rotation is kept in the H mode state, so that the humming change in engine speed is eliminated. Therefore, there is no audible engine speed change sound, and an aurally comfortable driving operation can be performed.

[Brief description of drawings]

FIG. 1 is a circuit diagram of essential parts showing a flow rate control device of the present invention.

FIG. 2 is a side view of a hydraulic excavator equipped with a crusher.

FIG. 3 is a circuit diagram of a main part of a conventional technique.

[Explanation of symbols]

 3, 3'Controller 7 Crusher 20 Pilot switching valve for crusher 22 Hydraulic remote control valve 24, 25 First and second pump 26 Regulator 28 Pilot pump 30 Working mode switching switch 82 Variable resistance operating part 83 Memory 84 Electromagnetic proportional pressure reducing valve 85 Pressure switch Pi Negative flow control pilot port Pm Maximum flow control pilot port

Claims (1)

[Claims] 1. A construction attachment is attached to the front part of a construction machine, a crusher, which is a special work machine, is attached to the tip of the work attachment, and a detection means for detecting the operation / non-operation of the crusher is provided. A flow rate control device for controlling a pump discharge flow rate for operating a crusher via a controller, wherein a variable resistance operation unit capable of changing a signal voltage up and down to perform a selection operation is provided for the controller. A predetermined current value to be output according to the signal voltage from the variable resistance operating section is stored in the memory of, and an electromagnetic proportional pressure reducing valve is arranged to derive a pilot pressure to act on the regulator of the variable pump. When the crusher is operated by adjusting the variable resistance operating unit, the variable resistance operating unit and the crusher operation detecting means are used to detect the The controller makes a judgment and outputs a command current value signal from the controller to the electromagnetic proportional pressure reducing valve, and the pilot pressure is applied to the regulator of the variable pump via the electromagnetic proportional pressure reducing valve to control the pump discharge flow rate. A flow control device for a crusher characterized by the above.