KR101978476B1 - Boom cylinder control system for excavator - Google Patents

Abstract

The present invention relates to a boom cylinder for performing a boom-up or a boom-down operation through a piston movement, a rod valve installed to be interlocked with a load chamber located at one side of the head in the boom cylinder and discharging hydraulic oil from the load chamber, A load pressure sensor installed in the load chamber for measuring a load pressure acting on the load chamber; a load pressure sensor installed in the load chamber to measure a load pressure acting on the load chamber; A head pressure sensor installed in the chamber for measuring a head pressure acting on the head chamber, and a controller for determining whether the excavator is in a jack-up state by using a load pressure and a head pressure provided from the rod pressure sensor and the head pressure sensor, And controls the rod valve and the head valve according to the result And controlling the operation of the boom cylinder. [0002] The present invention relates to a boom cylinder control system for an excavator.

Description

[0001] The present invention relates to a boom cylinder control system for an excavator,

The present invention relates to a boom cylinder control system for an excavator, and more particularly to a boom cylinder control system for an excavator capable of controlling a floating mode operation in a jack-up state of an excavator.

In general, an excavator performs a planarization operation to move the bucket forward and backward as well as to load, carry and unload the soil, at the construction site and to even out the ground.

In order to perform such a flattening operation, the movement of the boom and the bucket must 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 to the bucket by the bucket becomes too large to cause the bucket to pierce the ground. Conversely, if the force applied to the bucket by 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.

On the other hand, FIG. 1 shows an excavator in a jack-up state. As shown in the figure, in order to put the excavator 10 in a jack-up state, the bucket 13 is brought into contact with the ground surface through manipulation of the bucket hydraulic device 13a The boom hydraulic device 11a is operated to make the boom 11 into a boom up state to make the excavator 10 partially floated from the ground.

On the other hand, the boom hydraulic device 11a can be operated by its own weight in accordance with the curvature of the ground, and the operation of the excavator 10 in the floating mode state by performing the operation of the arm 12 only through the arm hydraulic device 12a .

Meanwhile, when the excavator body is jacked up by climbing the slope in a state where the dozer is mounted in front of the excavator, or when the excavator body is jacked up by the dozer to check or repair the lower part of the excavator, There is a problem in that a safety accident may occur due to a sudden drop of the equipment due to its own weight.

Disclosure of Invention Technical Problem [8] Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and it is an object of the present invention to provide a boom cylinder control system for an excavator, which can determine whether the excavator is in a jack- .

In order to achieve the above object, the present invention may include the following configuration.

A boom cylinder control system for an excavator according to the present invention comprises a boom cylinder for implementing a boom-up or a boom-down operation through a piston movement; A rod valve installed in the boom cylinder to interlock with a rod chamber disposed at one side of the head and discharging hydraulic oil from the rod chamber; A head valve installed to be interlocked with a head chamber located on the other side of the head in the boom cylinder and discharging hydraulic oil from the head chamber; A load pressure sensor installed in the load chamber for measuring a load pressure acting on the load chamber; A head pressure sensor installed in the head chamber for measuring a head pressure acting on the head chamber; And a controller for determining whether the excavator is in a jack-up state by using the load pressure and the head pressure provided from the load pressure sensor and the head pressure sensor, respectively. The control unit may control the operation of the boom cylinder by controlling the rod valve and the head valve depending on whether the boom cylinder is in the jack-up state.

The boom cylinder control system of the excavator according to the present invention has the following effects.

The present invention improves the accuracy of an operation for determining whether or not an excavator is in a jack-up state by using a pressure value measured by a load pressure sensor and a head pressure sensor, thereby preventing a floating mode from being operated in a jack-up state, There is an effect that a safety accident that may occur when the excavator descends can be prevented in advance.

1 shows an excavator in a jack-up state.
BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a boom cylinder control system for an excavator.
3 is a schematic configuration diagram for explaining a control unit according to a modified embodiment of the present invention;

The terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary meanings and the inventor may properly define the concept of the term to describe its invention in the best possible way And should be construed in accordance with the principles and meanings and concepts consistent with the technical idea of the present invention.

Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to FIGS. 1 to 3 attached hereto.

Fig. 2 is a schematic diagram showing a configuration of a boom cylinder control system of an excavator according to the present invention. Fig. 3 is a view for explaining a control unit according to a modified embodiment of the present invention. Fig.

The boom cylinder control system 100 of the excavator according to the present invention mainly includes a boom cylinder 110, a load valve 120, a head valve 130, a load pressure sensor 140, A sensor 150, and a controller 160.

FIG. 1 shows an excavator in a jack-up state. Hereinafter, the boom cylinder control system 100 of the excavator of the present invention will be described in detail with reference to a jack-up state of the excavator 10. FIG.

2 is a block diagram schematically showing the configuration of a boom cylinder control system of an excavator according to the present invention. Referring to the drawings, an excavator 10 basically comprises a boom down or boom the boom cylinder 110 is operated by controlling the load valve 120 and the head valve 130 in the control unit 160 through an operation on the boom control lever 162 .

Here, the boom cylinder control system 100 of the excavator according to the present invention includes a floating switch 161 for implementing the floating function, and the floating mode is selectively operated by the operation of the operator.

Referring to FIGS. 1 to 3, the boom cylinder control system 100 of an excavator will be described as follows.

The boom cylinder 110 serves to operate the boom 11 of the excavator 10 through piston motion.

That is, the boom cylinder 110 is for implementing a boom up or a boom down operation.

The boom cylinder 110 has a space in which the rod 111 and the head 112 can move. The operating oil for generating the hydraulic pressure in the space is supplied and filled or discharged. The boom cylinder 110 includes a load chamber 110a (shown in Fig. 3) and a head chamber 110b (shown in Fig. 3). The rod chamber 110a is a portion of the boom cylinder 110 in which the rod 111 is located with respect to the head 112. The head chamber 110b is located on the opposite side of the load chamber 110a with respect to the head 112 inside the boom cylinder 110. [ That is, the load chamber 110a is located at one side of the head 112 in the boom cylinder 110, and the head chamber 110b is located at the other side of the head 112. As the rod 111 and the head 112 move, the volume of each of the load chamber 110a and the head chamber 110b is changed.

Next, the rod valve 120 serves to discharge operating oil from the load chamber 110a.

The rod valve 120 is installed in the rod chamber 110a so as to communicate with the hydraulic oil pipeline through which the hydraulic oil can be transferred, and is constructed of a solenoid type that can cut off hydraulic oil supply.

In this case, when the hydraulic oil is discharged from the load chamber 11a, the hydraulic oil discharged from the load chamber 110a is stored in the hydraulic oil tank T installed in the rod valve 120 through the rod valve 120. [

The pump 170 is provided with a conduit through which the hydraulic fluid is delivered to the load chamber 110a to supply the hydraulic fluid to the boom cylinder 110 and a hydraulic fluid to be communicated with the conduit, And is supplied to the boom cylinder 110 after the operating fluid is supplied to the spool 180.

Accordingly, when the boom down operation is implemented, the working oil is supplied to the load chamber 110a, and when the boom up operation is implemented, the working oil is supplied from the load chamber 110a to the working oil tank T, Respectively.

Next, the head valve 130 serves to discharge the operating oil from the head chamber 110b.

The head valve 130 is installed in the head chamber 110b so as to communicate with the hydraulic oil line through which the hydraulic oil can be transferred, and is configured in a solenoid type that can cut off hydraulic oil supply.

At this time, when the hydraulic oil is discharged from the head chamber 110b, the hydraulic oil discharged from the head chamber 110b is stored in the hydraulic oil tank T installed in the head valve 130 through the head valve 130. [

A pipeline through which the hydraulic oil is delivered to the head chamber 110b is formed to supply the hydraulic oil to the boom cylinder 110. After the pump 170 is operated to supply the hydraulic oil to the spool 180, ).

Accordingly, when the boom down operation is implemented, the operating oil is supplied to the head chamber 110b, and when the boom up operation is implemented, the operating oil flows from the head chamber 110b to the working oil tank T .

The operating fluid is delivered to the spool 180 by the operation of the pump 170 and supplied to the head chamber 110b or the load chamber 110a via the spool 180 to be boom down or boom up, Operation is implemented.

Next, the rod pressure sensor 140 serves to measure the rod pressure acting on the rod chamber 110a.

The load pressure sensor 140 is installed in the load chamber 110a and interlocks with a control unit 160 to be described later to measure the load pressure with respect to the pressure in the internal space of the load chamber 110a.

At this time, the load pressure sensor 140 transmits the load pressure to the controller 160 when the measurement of the load pressure is completed.

Next, the head pressure sensor 150 serves to measure the head pressure acting on the head chamber 110b.

The head pressure sensor 150 is installed in the head chamber 110b and interlocks with the controller 160 to measure the head pressure against the pressure in the internal space of the head chamber 110b.

At this time, the head pressure sensor 150 transmits the head pressure to the controller 160 when the measurement of the head pressure is completed.

At this time, when the load pressure measured by the load pressure sensor 140 and the head pressure measured by the head pressure sensor 150 are transmitted to the controller 160, the controller 160 controls the load It is determined whether or not the terminal 10 is currently in the jack-up state.

For example, when the load pressure is larger than the head pressure, the excavator 10 may be judged to be in the jack-up state.

Meanwhile, in the process of determining that the excavator 10 is in the jack-up state, it is possible to determine that the excavator 10 is in the jack-up state even when the excavator 10 is released from the jack-up state.

Here, the fact that the load pressure is larger than the head pressure is a result that the force acting on the load chamber 110a is larger due to the jack-up state, and therefore, it is information that can accurately determine the state of the jack-up.

Therefore, when it is determined that the excavator 10 is in the jack-up state due to the difference between the head pressure and the load pressure, the excavator 10 is cut off through the control unit 160 so that the boom-down operation is not performed.

That is, when the excavator 10 is in the jack-up state, the floating mode can not be executed even if the floating switch 161 is turned on.

Next, the controller 160 controls the rod valve 120 and the head valve 130.

The controller 160 discharges the operating fluid from the load chamber 110a through the rod valve 120 to implement a boom up operation. The controller 160 discharges the hydraulic fluid from the head chamber 110b through the head valve 130 to implement a boom down operation.

The control unit 160 receives the load pressure and the head pressure from the load pressure sensor 140 and the head pressure sensor 150 and determines whether the excavator is in a jack-up state using the load pressure and the head pressure. The operation of the boom cylinder 110 is controlled by controlling the load valve 120 and the head valve 130. [

At this time, the controller 160 controls the load valve 120 and the head valve 130 so that the hydraulic oil can not be discharged through the rod valve 120 and the head valve 130 when the excavator 10 is in the jack-up state do.

Therefore, when the excavator 10 is judged to be in the jack-up state, the control unit 160 can limit the boom cylinder 110.

At this time, even if the floating switch 161 is operated to turn the excavator 10 to the floating mode, the control unit 160 may prevent the floating mode from being executed when the excavator 10 is judged to be in the jack-up state .

It is preferable that the boom down cut valve 190 is installed to be interlocked with the control unit 160 in order to prevent the hydraulic fluid from being supplied to the boom cylinder 110 during the boom down operation.

That is, the boom-down cut valve 190 can prevent the unnecessary hydraulic fluid from being supplied to the head chamber 110b during the boom-down operation.

Hereinafter, the operation of the boom cylinder control system of the excavator described above with reference to Figs. 1 and 2 will be described.

A situation in which the worker inadvertently turns on the floating switch 161 to operate the floating mode when the body of the excavator 10 is in a jack-up state for checking or repairing the lower part of the excavator 10 will be described as follows .

First, when the floating switch 161 is turned on by the operator, the control unit 160 senses the float switch 161 to prevent the boom cylinder 110 from operating. At this time, the pressure of the load pressure sensor 140 and the head pressure sensor 150 And transmits the measured data to the control unit 160.

Then, the control unit 160 compares the pressure values of the load pressure sensor 140 and the head pressure sensor 150 and determines that the excavator 10 is in the current jack-up state when it is determined that the pressure value is greater than the reference value.

The control unit 160 then blocks the hydraulic oil from being discharged to the hydraulic oil tank T of the rod valve 120 and the head valve 130.

The load valve 120 and the head valve 130 are maintained in a blocked state under the control of the controller 160 even if the float switch 161 or the boom control lever 162 is operated by carelessness of the operator.

Therefore, the boom cylinder 110 can be prevented from being operated in the jack-up state of the excavator 10.

In addition, even when the excavator 10 is in the jack-up state and the jack-up state is released, it is determined that the excavator 10 is in the jack-up state and is prevented from being switched to the floating mode.

The rod pressure sensor 140 and the head pressure sensor 150 are provided in the load chamber 110a and the head chamber 110b and the load pressure and the head pressure are measured and compared. It can be determined that the excavator 10 is in the jack-up state.

Accordingly, the boom cylinder control system 100 of the excavator according to the present invention is configured such that when the excavator 10 is in the jack-up state, the boom cylinder 110 is prevented from being operated and the floating mode is not operated, A safety accident that may occur when the excavator 10 suddenly descends can be prevented in advance.

Referring to FIG. 3, a modified embodiment of the controller 160 will now be described.

The controller 160 acquires a load force acting on the load surface 112a from the load pressure and acquires a head force acting on the head surface 112b from the head pressure. The rod surface 112a is a surface from the head 112 toward the load chamber 110a. The head surface 112b is a surface from the head 112 toward the head chamber 110b. The rod 112 is coupled to the rod surface 112a. Accordingly, the load area, which is an effective area in which the load pressure acts on the rod surface 112a, is smaller than the head area, which is an effective area where the head pressure acts on the head surface 112b. This is because the load area corresponds to the area excluding the area where the rod 112 is coupled from the rod surface 112a and the head area corresponds to the entire area of the head surface 112b.

When the controller 160 acquires the load force and the head force, the control unit 160 determines whether the load force is in a jack-up state by using a difference value obtained by subtracting the head force from the load force. Accordingly, the boom cylinder control system 100 of the excavator according to the present invention can achieve the following operational effects.

First, as described above, the rod surface 112a and the head surface 112b are implemented with different areas. Accordingly, forces of different magnitudes are applied to the rod surface 112a and the head surface 112b even when the same pressure acts on the rod chamber 110a and the head chamber 110b. Therefore, if only the pressure values acting on the rod chamber 110a and the head chamber 110b are used, the accuracy of the operation for determining whether or not the robot is in the jack-up state may be degraded.

Next, the boom cylinder control system 100 of the excavator according to the present invention is implemented to use the difference value between the load force and the head force reflecting the difference in size between the load area and the head area, Can be further improved. Therefore, the boom cylinder control system 100 of the excavator according to the present invention can stably block the operation of the floating mode in the jack-up state, thereby preventing a safety accident from occurring.

If the difference exceeds the predetermined reference force value, the controller 160 determines that the excavator is in the jack-up state and controls the excavator to prevent the boom operation from being performed. The reference force value is a value in consideration of an external force acting on the boom cylinder 100, and can be preset by the user. The controller 160 determines that the excavator is not in the jack-up state if the difference is less than the preset reference force value. As a result, the excavator 10 (shown in Fig. 1) becomes operable in the floating mode.

The controller 160 may obtain a difference value obtained by subtracting the head force from the load force through the following operation.

First, the controller 160 multiplies the load area on the load surface 112a excluding the area where the load 112 is coupled to obtain the load force. The load area can be obtained by an operation using the following equation (1).

[Equation 1]

In the equation (1), A _R is the load area on the rod surface 112a where the load pressure acts, D is the diameter of the head 112, and d is the diameter of the rod 111. The load pressure is provided from the load pressure sensor 140. The load area may be obtained by calculation in advance and stored in the controller 160. [

Next, the controller 160 obtains the head force by multiplying the head area with respect to the head surface 112b by the head pressure. The head area can be obtained by an operation using the following equation (2).

&Quot; (2) "

In Equation (2), A _H is the head area where the head pressure acts on the head surface 112b, and D is the diameter of the head 112. The headed pressure is provided from the head pressure sensor 150. [ The head area may be obtained by calculation in advance and stored in the controller 160.

Next, the controller 160 compares the load force obtained by multiplying the load area by the load pressure and the head force obtained by multiplying the head pressure by the head pressure and the reference force value so that the excavator 10 It is determined whether or not it is in the jack-up state. This can be expressed as Equation 3 below.

&Quot; (3) "

In Equation 3, P _Rod is the load pressure, A _Rod is the load area, P _Head is the head pressure, A _Head is the head area, and F _a is the reference force value.

The control unit 160 determines that the excavator 10 is in the jack-up state if the difference obtained by subtracting the head force from the load force in Equation (3) is greater than the reference force value. The control unit 160 determines that the excavator 10 is not in the jack-up state if the difference obtained by subtracting the head force from the load force in Equation (3) is less than the reference force value.

According to a modified embodiment of the present invention, the controller 160 may determine whether the vehicle is in a jack-up state by using the load pressure, and then determine whether the vehicle is in a jack-up state by using the difference value. In this case, the controller 160 determines that the load pressure is not in a jack-up state when the load pressure is less than a preset reference pressure value, and determines whether the difference value exceeds the reference force value if the load pressure exceeds the reference pressure value It is judged whether or not it is in the jack-up state. The reference pressure value is a value in consideration of the safety factor for the load pressure in the case of not being in the jack-up state, and can be set in advance by the user. The safety factor that is considered in the reference pressure value may be a smaller ratio than the safety factor that is considered in the reference force value.

Therefore, when the boom cylinder control system 100 of the excavator according to the present invention is unclear from the load pressure, it is judged whether or not the difference value exceeds the reference force value, It is possible to further improve the accuracy with respect to the load pressure and to prevent the operation of the floating mode from being delayed by being implemented not to judge whether the difference value exceeds the reference force value when it is clear from the load pressure that it is not in the jack- can do. Specifically, it is as follows.

First, in the deceleration section in which the jack-up state ends, the load pressure gradually decreases. This can be seen from the following equations (4) to (9).

&Quot; (4) "

In the equation (4), F _down is a load force, F _up is a head force, and F _external is an external force acting on the boom cylinder. The value (ma) obtained by subtracting the head force and the external force from the load force corresponds to the deceleration section in which the jack-up state is ended, and thus represents a negative value.

&Quot; (5) "

Equation (5) represents the load force and the head force in Equation (4) by converting the load pressure, the load area, the head pressure, and the head area. In the equation (5), P _R is the load pressure, A _R is the load area, P _H is the head pressure, and A _H is the head area.

&Quot; (6) "

Equation (6) assumes that the head area in Equation (5) corresponds to twice the load area.

&Quot; (7) "

&Quot; (8) "

&Quot; (9) "

Equations (7) to (9) show a process of arranging the load pressure only on the left side based on Equation (6).

As a result, it can be seen from Equation (9) that the load pressure gradually decreases in the deceleration section at which the jack-up state ends.

Therefore, if the control unit 160 determines whether or not the vehicle is in the jack-up state using only the load pressure, the workability of the operation of determining whether the vehicle is in the jack-up state in the deceleration section in which the jack- If the reference pressure value is set to a low value in consideration of a decrease in the load pressure in the deceleration section in which the jack-up state is ended, the controller 160 determines that the controller 160 is in the jack-up state and is not in the jack-up state. On the other hand, if the reference pressure value is set to be high, the controller 160 may determine that the controller 160 is not in the jack-up state as the load pressure is reduced in the deceleration section in which the jack-up state is terminated.

In order to solve this problem, the control unit 160 according to the modified embodiment of the present invention is implemented not to judge whether the difference value exceeds the reference force value when it is clear from the load pressure that it is not in the jack-up state, Can be prevented from being delayed. In addition, when it is unclear from the load pressure that the load is not in the jack-up state, the control unit 160 according to the modified embodiment of the present invention judges whether the difference value exceeds the reference force value, Can be further improved. Therefore, the boom cylinder control system 100 of the excavator according to the present invention can contribute to securing both the safety and effectiveness of the excavator 10 (shown in Fig. 1). In this case, the reference pressure value can be set to a low value in consideration of the decrease in the load pressure in the deceleration section in which the jack-up state is ended. Accordingly, even if the load pressure is considered, even if it is judged that the load is not in the jack-up state but is judged to be in the jack-up state, the controller 160 double judges whether the difference value is in the jack- Can be determined accurately.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. .

10: Excavator 11: Boom
11a: boom hydraulic device 12: arm
12a: arm hydraulic device 13: bucket
13a: Bucket hydraulic device 100: Boom cylinder control system of excavator
110: boom cylinder 110a: rod chamber
110b: head chamber 111: rod
112: head 112a: rod surface
112b: head surface 120: rod valve
130: head valve 140: rod pressure valve
150: head pressure valve 160:
161: Floating switch 162: Boom control lever
170: Pump 180: Spool
190: boom down cut valve T: working oil tank

Claims (5)

A boom cylinder for implementing a boom-up or boom-down operation through piston motion;
A rod valve installed in the boom cylinder to interlock with a rod chamber disposed at one side of the head and discharging hydraulic oil from the rod chamber;
A head valve installed to be interlocked with a head chamber located on the other side of the head in the boom cylinder and discharging hydraulic oil from the head chamber;
A load pressure sensor installed in the load chamber for measuring a load pressure acting on the load chamber;
A head pressure sensor installed in the head chamber for measuring a head pressure acting on the head chamber; And
And a controller for determining whether the excavator is in a jack-up state by using a load pressure and a head pressure provided from the load pressure sensor and the head pressure sensor, respectively,
Wherein the control unit controls the operation of the boom cylinder by controlling the load valve and the head valve depending on whether the boom cylinder is in the jack-up state,
The head including a load face toward the load chamber and a head face toward the head chamber;
Wherein the control unit obtains a load force acting on the load surface from the load pressure, obtains a head force acting on the head surface from the head pressure, and subtracts the difference value from the load force And when it exceeds the predetermined reference force value, it is judged that the excavator is in the jack-up state and the boom-down operation is prevented from being performed. delete The method according to claim 1,
A rod is coupled to the rod surface;
Wherein the control unit multiplies the load area by the load area excluding the area where the load is coupled on the load surface to obtain a load force and multiplies the head area by the head area against the head area to multiply the head force The boom cylinder control system comprising: The method according to claim 1,
Wherein the controller determines that the excavator is not in a jack-up state when the load pressure is equal to or less than a preset reference pressure value, and if the load pressure exceeds the reference pressure value, State of the boom cylinder of the excavator. The method according to claim 1,
And a boom down cut valve is installed to be interlocked with the control unit to shut off hydraulic oil from being supplied to the boom cylinder during the boom down operation.

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