KR20140081989A

KR20140081989A - Boom Cylinder Control Circuit for Excavator

Info

Publication number: KR20140081989A
Application number: KR1020120150596A
Authority: KR
Inventors: 이종원
Original assignee: 두산인프라코어 주식회사
Priority date: 2012-12-21
Filing date: 2012-12-21
Publication date: 2014-07-02

Abstract

The present invention relates to a boom cylinder control circuit for an excavator and includes a boom cylinder having a rising chamber and a falling chamber, a control unit for receiving a signal from the floating selection control unit or the floating release control unit and controlling the floating selection valve, A floating valve for connecting or disconnecting the up and down chambers with the drain line, and a pressure sensor for measuring the pressure of the down chamber and sending the measured value to the control unit.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a Boom Cylinder Control Circuit for Excavator,

The present invention relates to a boom cylinder control circuit for an excavator, and more particularly to a boom cylinder control circuit for an excavator, characterized by measuring the rod-side chamber pressure of the boom cylinder and controlling the operation of the floating selection valve according to the value .

Generally, the excavator performs the planarization work to move the bucket forward and backward as well as to load, carry and unload the soil at the construction site. In order to perform such a flattening operation, the movement of the boom and the bucket should be finely controlled so that the load applied to the bucket by the operator is kept constant.

However, if the control of the boom is not precise when the planarizing operation is performed, the force applied by the bucket to the ground is too large to cause the bucket to pierce the ground. Conversely, if the force applied to the bucket is too small, Is not achieved.

Excavators can also be used by replacing the bucket with an optional work machine such as a breaker. The breaker is an optional device for crushing rocks, pavements and the like.

However, at the moment when the breaker breaks the object to be crushed, a phenomenon that the boom tries to bounce up due to action and reaction occurs, so the operator has to control the boom and the breaker more precisely.

In this way, when the excavator performs the flattening operation or the breaker operation, the worker must precisely operate the boom, the bucket, the boom and the breaker, but it is difficult to precisely control the worker.

In order to solve such a problem, the excavator has a floating function. By this floating function, the operator can prevent the unintentional operation of the work device in the process of performing the planarization work or the breaker work.

The floating function means that the working oil in the no-load state (the state in which the ascending chamber and the descending chamber of the hydraulic cylinder are in communication with each other) is supplied to the working surface or the road surface Is driven according to the degree of bending of the motor.

However, when the excavator body is jacked up by jacking up the body of the excavator to check or repair the lower part of the excavator, or when the excavator body is jacked up by the dozer while climbing the slope with the dozer mounted on the front of the excavator, When operated, the vehicle body does not rise due to boom down, but rather falls, resulting in a safety hazard.

Patent Publication No. 10-2010-0056087 (published on May 27, 2010)

In order to solve the above problems, a pressure sensor is provided in a rod-side chamber of a boom cylinder, and the operation of the floating selection valve is controlled by comparing measured pressure values, Function to prevent unexpected descent of the excavator.

In order to achieve the above object, a boom cylinder control circuit of an excavator according to the present invention comprises a boom cylinder 1 having a rising chamber 1a and a falling chamber 1b; A control unit (60) for receiving the signals from the floating selection control unit (10) or the floating release control unit (20) and controlling the floating selection valve (50); A floating valve 30 for receiving a signal from the floating selection valve 50 and connecting or disconnecting the uprising chamber 1a and the downrising chamber 1b to or from the drain line and a controller for measuring the pressure of the downrising chamber 1b, And a pressure sensor (70) for sending a value to the controller (60).

The control unit 60 controls the operation of the floating selection valve 50 according to the magnitude of the pressure measured by the pressure sensor 70.

In addition, when the pressure measured by the pressure sensor 70 is 200 bar or more, the control unit 60 stops the operation of the floating selection valve 50.

The above-described effects of the present invention are as follows. First, safety incidents that may occur during a jack-up process of an excavator can be prevented through a simple additional configuration. Second, the excavator can be operated economically by controlling the boom according to the pressure of the boom cylinder of the excavator.

1 is an explanatory view of a jack-up function of an excavator;
2 is an explanatory view of a boom cylinder control circuit of a general excavator,
3 is an explanatory view of a boom cylinder control circuit of an excavator according to the present invention.

Hereinafter, a boom cylinder control circuit for an excavator according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can readily implement the present invention. The present invention is not limited to the embodiments described herein, but may be embodied in many different forms.

In order to clearly illustrate the present invention, parts not related to the description are omitted, and the same or similar components are denoted by the same reference numerals throughout the specification.

1 is an explanatory view of a jack-up function of an excavator. As shown in Fig. 1, the excavator is connected to the boom 85, the boom cylinder 1, the arm 87, the arm cylinder 11, the bucket 89 and the bucket cylinder 21, The boom 85, the arm 87, the bucket 89 and the like are actuated by the operation of the cabin provided in the boom 85,

The bucket 89 may be replaced with a working machine such as a breaker (not shown) and a forceps (not shown), which are various optional devices, and the lower traveling body 83 of the excavator may be replaced with a wheel or a crawler .

The dozer blade (not shown) may be provided on the lower traveling body 83. The dozer blade may function to smooth the ground according to the running of the excavator, and may also support the excavator safely have.

As shown in Fig. 1, the excavator has a jack-up function. The jack-up means that the car body of the excavator is lifted to repair or inspect the lower part of the excavator, and the bucket 89 is fixed on the ground to lower the boom 85 in order to jack up the excavator.

In order to lower the boom 85, the hydraulic fluid flows into the lower chamber 1b, which is the rod-side chamber of the boom cylinder 1, and the bucket 89, which is supported on the ground, 85 and the body of the excavator are brought close to each other, the front portion of the excavator is lifted. Also, when the excavator is supported by the dozer blade at an inclined place or the like, the jack-up state described above may occur.

2 is an explanatory view of a boom cylinder control circuit of a general excavator. The excavator includes a boom cylinder 1 having a rising chamber 1a and a falling chamber 1b, a floating selection operation portion 10, A control unit 60 for controlling the floating selection valve 50 in response to a signal from the floating selection valve 50 and a control unit 60 for controlling the floating selection valve 50 so as to connect or disconnect the rising chamber 1a and the down chamber 1b to / And a floating valve (30).

FIG. 3 is an explanatory view of a boom cylinder control circuit of an excavator according to the present invention. The boom cylinder control circuit of the excavator according to the present invention measures the pressure of the falling chamber 1b, And a pressure sensor 70 for detecting the pressure of the fluid.

In the excavator, the working oil in the no-load state (the state in which the ascending chamber and the descending chamber of the hydraulic cylinder are in communication with each other) in the state where the hydraulic oil from the hydraulic pump is temporarily cut off from the hydraulic cylinder driving the working device, And has a floating function for driving according to the degree of bending.

That is, the excavator can maintain the floating state by selectively connecting the rising chamber 1a and the falling chamber 1b of the boom cylinder 1 with the drain line t according to the operation characteristics.

The boom cylinder control circuit of the excavator according to the present invention is also applicable to a boom cylinder control circuit of the excavator according to the present invention in a bidirectional floating mode in which both the rising chamber 1a and the falling chamber 1b of the boom cylinder 1 are floated, ) Can be efficiently implemented in the one-direction floating mode.

The boom cylinder control circuit of the excavator for implementing such a floating function includes a floating selection operation portion 10, a floating operation portion 20, a floating valve 30, a floating selection valve 50 and a control portion 60.

The floating selection operation unit 10 may select a normal operation mode, a one-direction floating mode, and a bi-directional floating mode, and the general operation mode refers to a work mode in which the floating function is interrupted.

In the bidirectional floating mode, when the boom 85 is free to move upward and downward and presses the ground surface by the weight of the boom 85, It can be used as a flattening operation or a land selection operation.

Further, the one-direction floating mode may be a breaker mode for restricting the boom from being raised and allowing the boom to descend and crushing the object.

The floating valve 30 selectively connects the rising chamber 1a and the falling chamber 1b of the boom cylinder 1 to the drain line t. When the rising chamber 1a and the falling chamber 1b of the boom cylinder 1 are initially shut off and one of the one-direction floating mode and the two-way floating mode is selected by the floating selection operation unit 10, 91 and the lower chamber 1b are communicated with the drain line t.

Specifically, the floating valve 30 is provided with first and second input ports 31 and 32 on one side and first and second output ports 33 and 34 on the other side. The first input port 31 is connected to the lower chamber 1b of the boom cylinder 1 and the second input port 32 is connected to the upper chamber 1a of the boom cylinder 1.

When the boom operation portion 3 is operated in this state, the pilot signal pressure generated from the boom operation portion 3 is supplied to the boom rising pressure portion and the boom down pressure portion of the boom control unit 4, and the boom control unit 4 And is controlled according to the provided pilot signal pressure.

The operating fluid discharged from the main pump p1 is controlled by the boom control unit 4 so as to be supplied to the rising chamber 1a and the falling chamber Ib of the boom cylinder 1, 1) causes the boom to move up or down.

Although the hydraulic valve 36 is provided in the floating valve 30, the floating valve 30 may be a solenoid valve that can be operated by an electrical signal.

The boom cylinder control circuit of the excavator according to the present invention further includes the pressure sensor (70). The pressure sensor 70 may be provided inside the lowering chamber 1b to measure the pressure of the lowering chamber 1b of the boom cylinder 1, It may also be measured proportionally depending on the size of the movement of the rod of the cylinder 1.

The pressure sensor 70 may be installed only on one side of the boom cylinder 1 and may be installed in the uprising chamber 1a to measure the pressure of the uprising chamber 1a, The pressure of the chamber 1b may be calculated.

The control unit 60 determines whether the excavator is in the jack-up state according to the input pressure of the lowering chamber 1b. To control the floating selection valve (50).

That is, in the jack-up state, the boom cylinder 1 is contracted and the boom 85 is lowered, so that the pressure of the lowering chamber 1b is high. therefore. Up state when the high pressure is measured by the pressure sensor 70 provided in the lowering chamber 1b and when the low pressure is measured by the pressure sensor 70, You can do it.

For example, if the pressure measured by the pressure sensor 70 is greater than 200 bar, it may be regarded as a jack-up condition. If the pressure is less than 200 bar, it may not be jack-up.

The reference value of the pressure measured by the pressure sensor 70 can be variously changed according to the condition of the work and the type and characteristics of the excavator, and may be set to preferably 190 bar to 210 bar.

When the pressure of the lowering chamber 1b measured by the pressure sensor 70 is 200 bar or more, the operator is in the jack-up state, so the operator further lowers the boom to further raise the body of the excavator. At this time, if the operator erroneously operates the floating selection operation unit, the floating mode of the excavator is implemented, and if the boom is lowered, the body of the excavator may suddenly descend.

Accordingly, when the pressure of the lowering chamber 1b measured by the pressure sensor 70 is greater than or equal to 200 bar, the controller 60 forcibly stops the operation of the floating selection valve 50. That is, the control unit 60 sends an operation stop signal to the floating selection valve 50 so that the floating function is not implemented even if the operator malfunctions the floating selection operation unit 10.

When the pressure of the downfalling chamber 1b measured by the pressure sensor 70 is less than 200 bar, the control unit 60 maintains the operation of the floating selection valve 50 to smoothly perform the floating operation of the excavator Can be implemented. That is, when the measurement pressure of the lowering chamber 1b is low, the operation of the floating selection valve 50 is continued even if the floating selection valve 50 is operated to increase the pressure of the lowering chamber 1b, It should be smooth.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims and their equivalents. And such changes are, of course, within the scope of the claims.

The present invention can be used in a boom cylinder control circuit of an excavator capable of controlling the floating function according to the pressure of the boom cylinder.

1: Boom cylinder 1a: Ascent chamber
1b: descent chamber 11: arm cylinder
21: Bucket cylinder 4: Boom control unit
10: Floating selection operation unit 20: Floating release operation unit
30: Floating valve 31: First input port
32: second input port 33: first output port
34: second output port 36: pressure receiving portion
50: Floating select valve
60: control unit 70: pressure sensor
81: upper revolving body 83: lower traveling body
85: Boom 87: Cancer
89: Bucket
p1: Main pump p2: Pilot pump

Claims

A boom cylinder 1 having a rising chamber 1a and a falling chamber 1b;
A control unit (60) for receiving the signals from the floating selection control unit (10) or the floating release control unit (20) and controlling the floating selection valve (50);
A floating valve 30 for receiving a signal from the floating select valve 50 to connect or disconnect the uprising chamber 1a and the downrising chamber 1b to or from the drain line; And
A pressure sensor 70 for measuring the pressure of the lowering chamber 1b and sending the measured value to the controller 60; The boom cylinder control circuit comprising:

The method according to claim 1,
Wherein the controller (60) controls the operation of the floating select valve (50) according to the magnitude of the pressure measured by the pressure sensor (70).

3. The method of claim 2,
Wherein the controller (60) stops the operation of the floating select valve (50) when the pressure measured by the pressure sensor (70) is 200 bar or more.