KR20000021940A - Booster for work equipment of construction machine - Google Patents

Abstract

PURPOSE: A booster is provided to increase a durability of an equipment by preventing an overload in a work equipment when the load over the pressure established in the work equipment is applied while working using a construction heavy equipment such as a loader. CONSTITUTION: A booster is composed of: a first sensor(18a) for detecting an operation pressure to a boom cylinder(14), a second sensor(18b) for detecting the operation pressure at a bucket cylinder(15), a third sensor(18c) for detecting a traveling speed of an equipment. And a variable relief valve(16) is established at a control valve(13) for returning the operation pressure to a hydraulic pressure tank(T) when the load over the pressure established in the boom cylinder(14) and the bucket cylinder(15) is applied. When the load over the pressure established in the boom cylinder(14) and the bucket cylinder(15) is applied, a solenoid valve(12) is established to be switched according to an input of a specific signal to a vent line(19) of the variable relief valve(16) for increasing an established pressure of the variable relief valve.

Description

Pressure booster for work equipment of construction machinery

The present invention relates to a pressure booster for a work device of a construction machine, and more particularly, to supply an extra working pressure to the work device when a load greater than the pressure set in the work device occurs while working with heavy equipment such as a loader The present invention relates to a booster for a work device of a construction machine to ensure continuity of work.

In general, the loader is mainly carried out by the work device to dig the load, excavate the load and lift it up to a desired height, and then run a predetermined distance to load the dump truck and the like (called "loading operation"). At this time, the working device is digging into the load and the driver moves the working device (boom or bucket) so that the load is optimally loaded on the working device.

1 is a hydraulic circuit diagram for a working device of a construction machine according to the prior art.

As shown, the hydraulic pump 1 driven by the engine not shown, the boom cylinder 4 and the bucket cylinder 5 is connected to the hydraulic pump 1, the hydraulic pump 1 and the boom cylinder ( Between 4) and the bucket cylinder 5, a control valve 2 for controlling the amount and flow direction of the working oil supplied to these cylinders is provided. At this time, the control valve (2) is a relief valve for protecting the hydraulic line and parts by returning the operating pressure to the hydraulic tank (6) when a load greater than the pressure set in the boom cylinder (4) and bucket cylinder (5) during operation ( Include 3).

However, a load set on the work device is generated in the process of digging into the load (relief state), and thus the work device does not move at all. That is, the maximum pressure (relief pressure) set in the boom or bucket driving cylinder is generated, and the working apparatus faces a state in which it cannot overcome the external load condition. Because of this, since the work is suspended, the driver is to reverse the work device in order to get out of the working condition, and then repeats the work to be dug into the load again, the work is delayed and workability is inferior.

In this way, the work device may move the load a little to get out of the limit condition in order to prevent the work delay. In other words, if the work device is forcibly moved to change the angle at which the work device digs into the load, and the work device that is in the limit state is released from the limit condition (relief state), the work device is released from the relief pressure state and the engine By allowing extra power to be supplied to the wheels of the machine, the continuity of the work was ensured by improving the traction of the machine.

As a result, the machine was overloaded, resulting in poor durability and increased operator fatigue.

Accordingly, an object of the present invention is to improve workability by securing the continuity of work by supplying an extra working pressure to the work device when a load greater than the pressure set in the work device occurs during work using heavy construction equipment such as a loader It is possible to provide, and to increase the durability of the equipment by preventing the overload of the working device to provide a boosting device for the working device of the construction machine.

1 is a hydraulic circuit diagram for a working device of a construction machine according to the prior art,

2 is a hydraulic circuit diagram of a boosting device for a work device of a construction machine according to an embodiment of the present invention.

* Explanation of symbols used in the main part of the drawing

11; hydraulic pump

12; solenoid valve

13; control valve

14; boom cylinder

15; bucket cylinder

16; variable relief valve

17; controller

18a; first sensor

18b; second sensor

18c; third sensor

18d; selector switch

19; VENT LINE

An object of the present invention described above is installed between a hydraulic pump, a boom cylinder and a bucket cylinder connected to and driven by the hydraulic pump, and installed between the hydraulic pump and the boom cylinder and the bucket cylinder to control the amount and flow direction of the working oil. A booster for a work machine of a construction machine having a control valve, comprising: a first sensor formed on the boom cylinder to detect an operating pressure of the boom cylinder; A second sensor formed in the bucket cylinder to detect an operating pressure of the bucket cylinder; A third sensor installed to detect a traveling speed of the equipment; A variable relief valve formed in the control valve and returning the operating pressure to the hydraulic tank when a load greater than the pressure set in the boom cylinder and the bucket cylinder is generated; A solenoid valve installed to be switched according to a predetermined signal input in the discharge flow path of the variable relief valve and switched when a load greater than the pressure set in the boom cylinder and the bucket cylinder is generated to increase the set pressure of the variable relief valve; A selection switch for selecting the variable relief valve control function by a driver; It is achieved by providing a boosting device for a work machine of a construction machine, characterized in that it further comprises a controller for applying a predetermined signal to the variable relief valve in accordance with the detection signal input from the selection switch and the respective sensors.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings, which are intended to assist in understanding the technical contents of the present invention, and thus the technical scope of the present invention is not limited.

A hydraulic pump 11 driven by an engine, a boom cylinder 14 and a bucket cylinder 15 connected to and driven by the hydraulic pump 11, a hydraulic pump 11, a boom cylinder 14 and a bucket cylinder ( It is applied to construction machinery such as a loader, which is installed between 15 and has a control valve 13 for controlling the amount and flow direction of the working oil.

Accordingly, according to a preferred embodiment of the present invention, the first sensor 18a for detecting the operating pressure thereof in the above-described boom cylinder 14 and the second sensor 18b for detecting its operating pressure in the bucket cylinder 15 are described. And third sensors 18c are installed to detect the traveling speed of the equipment, respectively, and when a load greater than the pressure set in the above-described boom cylinder 14 and the bucket cylinder 15 is generated, the hydraulic pressure is applied to the hydraulic tank T. The variable relief valve 16 (balance piston type relief valve) returning to the control valve 13 is installed in the control valve 13, and the variable relief valve 16 when a load greater than the pressure set in the boom cylinder 14 and the bucket cylinder 15 is generated. The solenoid valve 12 for increasing the set pressure of the variable relief valve 16 is installed to be switched in accordance with a predetermined signal input to the discharge passage 19 (VENT LINE) of the variable relief valve 16, and the variable relief valve 16 is controlled by the driver. The selector switch 18d is shaped so that the function can be selected. And a controller 17 for applying a predetermined signal to the variable relief valve 16 in accordance with the selection switch 18d and the detection signals input from the sensors 18a, 18b, and 18c.

Reference numeral 20 is a relief valve for returning the operating pressure to the hydraulic tank T when a load greater than the pressure set in the boom cylinder 14 and the bucket cylinder 15 occurs when the control function of the variable relief valve 16 is released. .

Referring to the operation of the boosting device for a working device of a construction machine according to an embodiment of the present invention configured as described above are as follows.

In other words, when loading the vehicle using heavy equipment such as a loader, a load of a pressure higher than the pressure set in the work device (boom or bucket) is generated during the work device digging into the load and loading the load into the bucket (relief state). If it does not move at all, the driver can drive the work tool to change the angle of entering the work tool to escape the relief phase of the work equipment.

That is, when the work device as described above is in the relief phase, the detection signal detected by the above-described sensors 18a, 18b, 18c and the selection switch 18d is input to the above-described controller 17, so that the controller 17 A predetermined signal from < RTI ID = 0.0 > 1) < / RTI > is applied to the solenoid valve 12 described above to switch the internal spool to the left side in the figure of FIG. For this reason, the discharge flow path 19 of the variable relief valve 16 mentioned above is interrupted | blocked by the solenoid valve 12 mentioned above.

Therefore, the working pressure of the working device is operated at the set pressure of the variable relief valve 16 described above (the set pressure of the variable relief valve 16 is set higher than the set pressure of the relief valve 20), As a result of the extra supply of the operating pressure discharged from the hydraulic pump 11 to the work device (boom or bucket), it is possible to escape the drive of the work device from the relief step.

On the other hand, when the work device is working in a normal state as a load under the set pressure out of the relief step, the above-described solenoid valve 12 is returned to its current state as shown in FIG. 2 by the restoring force of the valve spring 12a. It is switched (“a” state in FIG. 2), whereby the discharge passage 19 of the variable relief valve 16 described above is in communication with the relief valve 20. Accordingly, the drive of the work device is operated at the set pressure of the relief valve 20.

As described above, according to a preferred embodiment, when the load is greater than the pressure set in the work device during the operation using heavy construction equipment such as a loader, work by securing the continuity of work by supplying an extra working pressure to the work device It is possible to improve the durability, and to prevent the overload of the working device has the advantage to increase the durability of the equipment.

Claims (1)

A construction machine comprising a hydraulic pump, a boom cylinder and a bucket cylinder connected to and driven by the hydraulic pump, and a control valve installed between the hydraulic pump and the boom cylinder and the bucket cylinder to control the amount and flow direction of the working oil. In the booster for work equipment: A first sensor formed in the boom cylinder to detect an operating pressure of the boom cylinder; A second sensor formed in the bucket cylinder to detect an operating pressure of the bucket cylinder; A third sensor installed to detect a traveling speed of the equipment; A variable relief valve formed in the control valve and returning the operating pressure to the hydraulic tank when a load greater than the pressure set in the boom cylinder and the bucket cylinder is generated; A solenoid valve installed to be switched according to a predetermined signal input in the discharge flow path of the variable relief valve and switched when a load greater than the pressure set in the boom cylinder and the bucket cylinder is generated to increase the set pressure of the variable relief valve; A selection switch for selecting the variable relief valve control function by a driver; And And a controller for applying a predetermined signal to the variable relief valve according to the detection signal input from the selection switch and the respective sensors.