WO2017022868A1 - Apparatus for preventing drop of work equipment of construction machinery - Google Patents

Abstract

Disclosed is an apparatus for preventing the drop of a work equipment of construction machinery for adjusting a descending speed of the work equipment when leakage occurs in a return line while the work equipment is descending. Provided is an apparatus for preventing the drop of the work equipment of construction machinery according to the present invention, comprising a hydraulic cylinder which is driven by hydraulic oil of a hydraulic pump; a control valve which is installed in a flow path between the hydraulic pump and the hydraulic cylinder; an operating lever; a drop prevention valve which is installed in a flow path between the control valve and the large chamber of the hydraulic cylinder; a return pressure first detection sensor which is installed in a flow path between the control valve and the drop prevention valve; and a controller for adjusting an opening area of ​​the drop prevention valve when leakage occurs in the return line which returns the hydraulic oil from the hydraulic cylinder by a detection signal from the return pressure first detection sensor when the hydraulic cylinder is contracted and operated.

Description

Work device fall prevention device of construction machinery

The present invention relates to a work device fall prevention device, and more specifically, to the work device fall prevention device of the construction machine for adjusting the falling speed of the work device when the leakage occurs in the return line while the work device is lowered. It is about.

The work device fall prevention device of the construction machine according to the prior art shown in Figure 1,

The hydraulic pump 1 and the pilot pump (not shown) are connected to the engine or the like.

A hydraulic cylinder (referred to as a boom cylinder) 2 driven by hydraulic oil supplied from the hydraulic pump 1 is connected to the hydraulic pump 1.

A control valve (MCV) 3 for controlling the flow of hydraulic oil supplied to the hydraulic cylinder 2 is installed in the flow path between the hydraulic pump 1 and the hydraulic cylinder 2.

An operation lever (RCV) 4 for inputting a pilot pressure corresponding to the operation amount to the control valve 3 is provided between the pilot pump and the control valve 3.

A drop prevention valve 5 is installed in the flow path between the control valve 3 and the large chamber of the hydraulic cylinder 2.

In the figure, reference numeral 12 denotes a main relief valve.

In a construction machine such as an excavator including a boom falling by its own weight, when the hydraulic hose of the return line 6 for returning the hydraulic oil discharged when the hydraulic cylinder 2 is contracted and driven to the hydraulic oil tank T is broken. By the drop prevention valve (5) it can prevent the sudden drop of the working device.

As the pilot pressure according to the operation of the operating lever 4 is applied to the control valve 3 to switch the internal spool in the left or right direction in the drawing, the hydraulic oil of the hydraulic pump 1 is controlled by the control valve. It is supplied to and driven by the hydraulic cylinder 2 via (3).

On the other hand, when operating the operation lever 4 to shrink-drive the hydraulic cylinder 2, a part of the pilot pressure passing through the operation lever 4 is applied to the control valve (3) to view the inside Switch to up or right direction. Therefore, the hydraulic oil of the hydraulic pump 1 is supplied to the small chamber of the hydraulic cylinder 2 via the control valve 3, so that the working device can be lowered.

At the same time, when the hydraulic cylinder 2 is contracted and driven, a part of the pilot pressure passing through the operation lever 4 is applied to the valve spring opposite side of the drop prevention valve 5 so that the internal spool is shown in the drawing, By switching downward, the opening of the return line 6 is opened in a full state.

Accordingly, the driving speed of the hydraulic cylinder 2 is adjusted by the opening area of the control valve 3, so that the driver can lower the work device at a speed corresponding to the operation amount of the operating lever 4.

On the other hand, when the work device is lowered due to the contraction driving of the hydraulic cylinder 2, the pipeline (referred to as a hydraulic hose or hydraulic pipe) of the return line 6 bursts (hose burst) to generate oil leakage. In this case, the descending speed of the work tool is faster than the driver thinks.

As a result, it is impossible to operate the work device in a state required by the driver, and there is a problem that may cause damage to people around due to unexpected movement of the work device.

Therefore, the present invention is to solve the above-described problems, when the leakage occurs in the return line while the work device is lowered, the work of construction machinery that can stop the fall of the work device, or can operate at the speed intended by the driver An object of the present invention is to provide a device lowering prevention device.

According to one embodiment of the present invention to achieve the above and other objects of the present invention,

Hydraulic pump;

A hydraulic cylinder driven by the hydraulic oil of the hydraulic pump;

An operation lever for outputting an operation signal corresponding to the operation amount;

A control valve installed in a flow path between the hydraulic pump and the hydraulic cylinder, the hydraulic valve being switched when the pilot pressure corresponding to the operation amount of the operation lever is applied and controlling the flow of the hydraulic oil supplied to the hydraulic cylinder;

An anti-drop valve installed in a flow path between the control valve and the large chamber of the hydraulic cylinder;

A first pressure return sensor installed in a flow path between the control valve and the drop prevention valve;

A controller for adjusting an opening area of the drop prevention valve when leakage occurs in a return line for returning hydraulic oil from the hydraulic cylinder by a detection signal from the return pressure first detection sensor when the hydraulic cylinder is contracted and driven; It provides a work device fall prevention device of the construction machine characterized in that it comprises a.

According to another embodiment of the present invention to achieve the above and other objects of the present invention,

Hydraulic pump;

A hydraulic cylinder driven by the hydraulic oil of the hydraulic pump;

An electric operation lever for outputting an electric signal corresponding to the operation amount;

An electric control valve installed in a flow path between the hydraulic pump and the hydraulic cylinder and switched when an electrical signal corresponding to the operation amount of the operation lever is applied to control the flow of the hydraulic oil supplied to the hydraulic cylinder;

An anti-drop valve installed in a flow path between the electric control valve and the large chamber of the hydraulic cylinder;

A first pressure return sensor installed in a flow path between the electric control valve and the drop prevention valve;

An electric signal corresponding to the operation amount of the operation lever to the control valve and returning the hydraulic oil from the hydraulic cylinder by the detection signal from the return pressure first sensing sensor when the hydraulic cylinder is contracted and driven; When leakage occurs, the controller for adjusting the opening area of the drop prevention valve; provides a work device fall prevention device for a construction machine.

According to the present invention having the above-described configuration, in the event of an emergency situation in which leakage occurs due to a pipe rupture of the return line while the work device is being lowered, the lowering of the work device is stopped by blocking or reducing the opening of the return line. In addition, there is an effect that the operator can operate the work device at the intended descending speed.

1 is a hydraulic circuit diagram of the work device fall prevention device of the construction machine according to the prior art,

Figure 2 is a hydraulic circuit diagram of the work device fall prevention device of the construction machine according to a preferred embodiment of the present invention,

3 is a hydraulic circuit diagram showing a normal operation when the work device is lowered in the work device lowering prevention device shown in FIG.

4 is a hydraulic circuit diagram showing that in the work device lowering prevention device shown in Figure 2, leakage occurs in the return line when the work device is lowered to reduce the opening of the return line,

5 is a hydraulic circuit diagram of the work device fall prevention device of a construction machine according to another embodiment of the present invention,

6 is a hydraulic circuit diagram of a work device lowering prevention device of a construction machine according to another preferred embodiment of the present invention.

<Explanation of reference numerals for the main parts of the drawings>

One; Hydraulic pump

2; Hydraulic cylinder

3; Control Valve (MCV)

4; Operating lever (RCV)

5; Drop prevention valve

6; Return line

7; Return pressure 1st detection sensor

8; Controller (ECU)

9; Return pressure second detection sensor

10; Pilot pressure sensor

Hereinafter, with reference to the accompanying drawings will be described in detail the work device fall prevention device of the construction machine according to an embodiment of the present invention.

2 is a hydraulic circuit diagram of the work device fall prevention device of a construction machine according to a preferred embodiment of the present invention, Figure 3 is a hydraulic circuit diagram showing the normal operation when the work device is lowered in the work device fall prevention device shown in FIG. 4 is a hydraulic circuit showing that leakage occurs in the return line when the work device is lowered in the work device lowering prevention device shown in FIG. 2 to reduce the opening of the return line, and FIG. 5 is another preferred embodiment of the present invention. Hydraulic circuit diagram of the work device fall prevention device of the construction machine according to Figure 6 is a hydraulic circuit diagram of the work device fall prevention device of the construction machine according to another preferred embodiment of the present invention.

2 to 4, the work device fall prevention device of the construction machine according to an embodiment of the present invention

The hydraulic pump 1 and the pilot pump (not shown) are connected to the engine or the like.

A hydraulic cylinder (referred to as an boom cylinder, for example) 2 driven by hydraulic oil supplied from the hydraulic pump 1 is connected to the hydraulic pump 1.

At the time of switching, a control valve (MCV) 3 for controlling the flow of hydraulic oil supplied from the hydraulic pump 1 to the hydraulic cylinder 2 is installed in the flow path between the hydraulic pump 1 and the hydraulic cylinder 2. .

An operation lever (RCV) 4 for inputting a pilot pressure corresponding to the operation amount to the control valve 3 is provided in a flow path between the pilot pump and the control valve 3.

When leakage occurs in the return line 6 which returns hydraulic oil discharged from the hydraulic cylinder 2 to the hydraulic oil tank T when the hydraulic cylinder 2 is contracted and driven, the opening of the return line 6 is opened. A drop prevention valve (5) is provided in the flow path between the control valve (3) and the large chamber of the hydraulic cylinder (2) for interrupting or reducing the lowering speed of the work device.

A return pressure first detection sensor 7 for detecting the pressure of the working oil of the return line 6 is installed in the flow path between the control valve 3 and the drop prevention valve 5.

When leakage occurs in the return line 6 due to a detection signal from the return pressure first detection sensor 7 when the hydraulic cylinder 2 is contracted and driven (the hydraulic hose of the return line 6 bursts). While the pressure in the hydraulic hose maintains the set pressure, when the hydraulic hose in the return line 6 is ruptured and leaks, the pressure in the hydraulic hose is rapidly lowered to atmospheric pressure), the drop prevention valve 5 A controller (ECU) 8 for adjusting the opening area of the valve is connected to the drop prevention valve 5.

Although not shown in the figure, as the drop prevention valve (5)

An initial state of opening the return line 6 and a solenoid valve switched to an ON state to switch the return line 6 to a closed state when an electrical signal is applied from the controller 8 may be used. .

As the drop prevention valve (5)

An electromagnetic proportional pressure reducing valve (PPRV) for generating a secondary pressure corresponding to the electrical signal applied from the controller 8 and adjusting the opening area of the return line 6 to correspond to the generated secondary pressure may be used. have.

At this time, the electromagnetic proportional pressure reducing valve has a first state of opening the opening of the return line 6 to a full state and a second state of closing the opening of the return line 6. And a third state in which the opening of the return line 6 is partially reduced.

The operating lever (RCV) (4) may be a hydraulic operating lever for applying a pilot pressure corresponding to the operation amount to the control valve (8).

And a return pressure second detection sensor (9) installed in the flow path between the large chamber of the hydraulic cylinder (2) and the drop prevention valve (5), wherein the controller (8) includes the return pressures (1, 2). When the pressure difference of the hydraulic oil detected by the detection sensors 7 and 9 exceeds the set value, it is determined that leakage occurs in the return line 6 (that is, no leakage occurs in the return line 6). In this case, the difference in the pressure value of the hydraulic oil detected by the return pressure first and second detection sensors 7 and 9 maintains a constant value), and an electrical signal is applied to the drop prevention valve 5 to reduce the opening area. Can be reduced or closed.

That is, the hydraulic oil pressure value of the large chamber of the hydraulic cylinder 2 sensed by the return pressure second detection sensor 9 and the returned hydraulic oil pressure value sensed by the return pressure first pressure sensor 7. When the differential pressure exceeds the set value, the controller 8 determines that leakage occurs in the return line 6 and applies an electrical signal to the drop prevention valve 5.

As in Figure 5, the drop prevention valve (5)

The control valve 15 (for example, ON, OFF valves may be used) installed in the return line 6, and connected to the control valve 15, the controller ( It may be composed of an electromagnetic proportional pressure reducing valve 13 for generating a secondary pressure corresponding to the electrical signal applied from 8) to apply the secondary pressure generated to the control valve 15 to switch.

That is, during the return of the hydraulic oil from the large chamber through the control valve 15 to the hydraulic oil tank T due to the contraction driving of the hydraulic cylinder 2, the first pressure sensor 7 detects the return pressure. When the pressure value of the return line 6 is less than or equal to a set value, the controller 8 determines that leakage occurs in the return line 6 and applies an electrical signal to the electromagnetic proportional pressure reducing valve 13. The electromagnetic proportional pressure reducing valve 13 generates a secondary pressure corresponding to the applied electrical signal and applies the generated secondary pressure to the control valve 15. This interrupts the return line 6 due to the switching of the control valve 15 (in the state shown in FIG. 5).

And a pilot pressure sensor 10 for sensing a pilot pressure by operating the manipulation lever 4. The pilot pressure detected by the pilot pressure sensor 10 and applied to the control valve 3 is provided. When the hydraulic cylinder 2 is driven while the value maintains the set value, when the pressure value of the return oil detected by the return pressure first detection sensor 7 is equal to or less than the set value, the controller 8 It may be determined that leakage occurs in the return line 6.

That is, when the hydraulic cylinder 2 is a normal driving condition by the hydraulic oil supplied from the hydraulic pump 1, the pressure in the return line 6 detected by the return pressure first detection sensor 7 is The set value is maintained. On the other hand, when the hydraulic hose of the return line 6 is ruptured and leaks, the pressure value in the return line 6 detected by the return pressure first detection sensor 7 is lowered to atmospheric pressure.

According to the above-described configuration, the normal operation when the working device of the excavator descends will be described with reference to FIGS. 2 and 3.

An operation signal for operating the start switch 11 by the driver is input to the controller 8. Therefore, the spool of the drop prevention valve 5 is switched downward in the drawing by the electrical signal applied from the controller 8 to the drop prevention valve 5 to open the opening area in a full state. (State shown in FIG. 3).

At this time, when operating the operation lever 4 to shrink and drive the hydraulic cylinder 2 to lower the work device, a pilot pressure applied through the operation lever 4 from a pilot pump (not shown) This switches the spool of the control valve 3 to the right in the drawing.

Thus, the hydraulic oil discharged from the hydraulic pump 1 is supplied to the small chamber of the hydraulic cylinder 2 via the control valve 3. At the same time, the hydraulic oil discharged from the large chamber of the hydraulic cylinder 2 is returned to the hydraulic oil tank T via the drop prevention valve 5 and the control valve 3 in sequence.

Therefore, it is possible to lower the work device due to the contraction driving of the hydraulic cylinder (2). The descending speed of the work device is controlled by the opening area of the control valve 3 by the pilot pressure applied to the control valve 3 so as to correspond to the operation amount of the operation lever 4.

Hereinafter, leakage occurs in the return line when the work device is lowered to reduce the opening of the return line with reference to FIGS. 2 and 4.

As described above, the spool of the drop prevention valve 5 is switched to an open state by an electrical signal applied from the controller 8 due to the operation of the start switch 11, and the operation of the operation lever 4 is performed. Therefore, when a pilot pressure is applied and the spool of the control valve 3 is switched, the hydraulic oil of the hydraulic pump 1 may be supplied to the hydraulic cylinder 2.

At this time, when the hydraulic oil pressure value detected by the return pressure first detection sensor 7 installed in the return line 6 and input to the controller 8 is lower than a set value (for example, the hydraulic cylinder 2). From the hydraulic oil pressure value returned to the hydraulic oil tank T from " 0 "), the controller 8 determines that the return line 6 is ruptured and leakage occurs.

That is, when the hydraulic oil discharged from the large chamber is returned to the hydraulic oil tank T due to the contraction driving of the hydraulic cylinder 2, the pressure in the hydraulic hose is set before the hydraulic hose of the return line 6 is ruptured. Will be maintained. On the other hand, when the hydraulic hose of the return line 6 is ruptured and the hydraulic fluid is scattered when the hydraulic cylinder 2 is contracted and driven, the pressure in the hydraulic hose is rapidly lowered to atmospheric pressure (ie, the pressure in the hydraulic hose is " Down to 0 ").

Accordingly, the controller 8 determines that leakage occurs in the return line 6 and applies an electrical signal to the drop prevention valve 5 to reduce or close the opening of the return line 6. .

That is, the drop prevention valve 5 generates the secondary pressure to correspond to the electrical signal applied from the controller 8, and adjusts the opening area of the drop prevention valve 5 to correspond to the generated secondary pressure. Done.

That is, the drop prevention valve 5 is switched to close the opening of the return line 6 (as shown in FIG. 2), or to adjust to partially reduce the opening of the return line 6. (State shown in FIG. 4), the descent speed of the work tool may be stopped or adjusted to a desired reduced descent speed.

Therefore, even in an emergency situation in which leakage occurs due to rupture of the return line 6 while the hydraulic cylinder 2 is contracted and driven to lower the work device, the hydraulic oil tank T from the hydraulic cylinder 2. By cutting off or delaying the working oil returned to the tool, it is possible to prevent the work device from falling rapidly.

6 is a hydraulic circuit diagram of a work device lowering prevention device of a construction machine according to another preferred embodiment of the present invention.

Referring to FIG. 6, the hydraulic pump 1 and the pilot pump (not shown) are connected to an engine or the like.

A hydraulic cylinder (referred to as an boom cylinder, for example) 2 driven by hydraulic oil supplied from the hydraulic pump 1 is connected to the hydraulic pump 1.

An electric operation lever 4 (RCV) for outputting an electric signal corresponding to the operation amount is connected to the controller 8. At this time, as the electrical signal corresponding to the operation amount of the electric operation lever 4 is input to the controller 8, by detecting the pilot pressure by the operation of the hydraulic operation lever 4 shown in FIG. The pilot pressure sensor 10 output to the controller 8 becomes unnecessary.

An electric control valve 14 (MCV) which switches when an electric signal is applied by the operation of the electric operation lever 4 and controls the flow of the hydraulic oil supplied to the hydraulic cylinder 2 is provided with the hydraulic pump 1 and the hydraulic pressure. It is provided in the flow path between the cylinders 2.

When leakage occurs in the return line 6 which returns hydraulic oil discharged from the hydraulic cylinder 2 to the hydraulic oil tank T when the hydraulic cylinder 2 is contracted and driven, the opening of the return line 6 is opened. A rupture valve (5) is provided between the large chamber of the electric control valve (14) and the hydraulic cylinder (2) to shut off or reduce the speed of lowering the work device (e.g., the boom). Is installed in the flow path.

A return pressure first detection sensor 7 for detecting the pressure of the working oil of the return line 6 is installed in the flow path between the drop prevention valve 5 and the electric control valve 14.

An electric signal corresponding to the operation amount of the electric operation lever 4 is applied to the control valve 14, and when the hydraulic cylinder 2 is contracted and driven, the detection signal from the return pressure first detection sensor 7 is applied. When leakage occurs in the return line 6, a controller (ECU) 8 for adjusting the opening area of the drop prevention valve 5 is connected to the drop prevention valve 5.

At this time, the electric operation lever 4 outputting an electric signal corresponding to the operation amount to the controller 8 and an electric signal applied from the controller 8 so as to correspond to the operation amount of the electric operation lever 4. The configuration except for the electric control valve 14 to be switched is the same as the configuration of the work device lowering prevention device according to an embodiment of the present invention shown in FIG.

Herein, while the present invention has been described with reference to the preferred embodiments, those skilled in the art will variously modify the present invention without departing from the spirit and scope of the invention as set forth in the claims below. And will be able to change.

According to the present invention having the above-described configuration, when leakage occurs in the return line while the work device of the excavator is lowered, there is an effect of stopping the fall of the work device or adjusting the speed of the work device intended by the driver.

Claims (9)

1. Hydraulic pump;

   A hydraulic cylinder driven by the hydraulic oil of the hydraulic pump;

   An operation lever for outputting an operation signal corresponding to the operation amount;

   A control valve installed in a flow path between the hydraulic pump and the hydraulic cylinder, the hydraulic valve being switched when the pilot pressure corresponding to the operation amount of the operation lever is applied and controlling the flow of the hydraulic oil supplied to the hydraulic cylinder;

   An anti-drop valve installed in a flow path between the control valve and the large chamber of the hydraulic cylinder;

   A first pressure return sensor installed in a flow path between the control valve and the drop prevention valve;

   A controller for adjusting an opening area of the drop prevention valve when leakage occurs in a return line for returning hydraulic oil from the hydraulic cylinder by a detection signal from the return pressure first detection sensor when the hydraulic cylinder is contracted and driven; Falling prevention device of the work machine of the construction machine comprising a.
2. The method of claim 1, wherein the drop prevention valve

   And a solenoid valve which is switched on to switch the return line to the closed state when an initial state of opening the return line and an electrical signal from the controller is used.
3. According to claim 1, wherein the drop prevention valve

   An electromagnetic proportional pressure reducing valve for generating a secondary pressure corresponding to the electrical signal applied from the controller and adjusting the opening area of the return line to correspond to the generated secondary pressure is used. Preventing falling of the work machine of a construction machine, comprising a first state of opening the opening in the pull state, a second state of closing the opening of the return line, and a third state of partially reducing the opening of the return line. Device.
4. The method of claim 1,

   The operation lever is a fall prevention device for a construction machine, characterized in that a hydraulic operation lever for applying a pilot pressure corresponding to the operation amount to the control valve is used.
5. The method of claim 1,

   And a return pressure second detection sensor installed in a flow path between the large chamber and the drop prevention valve of the hydraulic cylinder, wherein the controller is configured to set a pressure difference between the hydraulic fluid detected by the return pressure first and second detection sensors. When it is determined that the leakage line is generated in the return line, by applying an electrical signal to the drop prevention valve to reduce or close the work area of the construction machine work equipment fall prevention device.
6. The method of claim 1, wherein the drop prevention valve

   An electromagnetic proportional pressure reducing valve connected to the control valve and the control valve installed in the return line, and generating a secondary pressure corresponding to the electrical signal applied from the controller to apply the secondary pressure generated to the control valve. Falling prevention device for a work machine of a construction machine, characterized in that consisting of.
7. The method of claim 1,

   And a pilot pressure sensor for sensing pilot pressure by operating the control lever, wherein the hydraulic pressure cylinder is applied to the control valve detected by the pilot pressure sensor to maintain a set value. In the case of driving the engine, when the return oil pressure value detected by the return pressure first detection sensor is less than the set value, the controller determines that the leakage oil is generated in the return line Working device lowering prevention device.
8. The method of claim 1,

   The hydraulic cylinder is a boom cylinder, characterized in that the work device fall prevention device of the construction machine.
9. Hydraulic pump;

   A hydraulic cylinder driven by the hydraulic oil of the hydraulic pump;

   An electric operation lever for outputting an electric signal corresponding to the operation amount;

   An electric control valve installed in a flow path between the hydraulic pump and the hydraulic cylinder and switched when an electrical signal corresponding to the operation amount of the operation lever is applied to control the flow of the hydraulic oil supplied to the hydraulic cylinder;

   An anti-drop valve installed in a flow path between the electric control valve and the large chamber of the hydraulic cylinder;

   A first pressure return sensor installed in a flow path between the electric control valve and the drop prevention valve;

   An electric signal corresponding to the operation amount of the operation lever to the control valve and returning the hydraulic oil from the hydraulic cylinder by the detection signal from the return pressure first sensing sensor when the hydraulic cylinder is contracted and driven; When the leakage occurs, the controller for adjusting the opening area of the drop preventing valve; the work device fall prevention device of the construction machine characterized in that it comprises a.

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