KR19980061407U - Hydraulic Balanced Circuit of Heavy Equipment - Google Patents

Abstract

The present invention relates to a hydraulic balance circuit of heavy equipment, and more particularly, in the hydraulic balance circuit of heavy equipment, an actuator operated by the pressure oil discharged from the hydraulic pump, installed in the flow path between the hydraulic pump and the actuator pilot operation A plurality of hydraulic cylinders installed between the direction switching valve and the actuator for opening and closing the flow path by a plurality of hydraulic cylinders to drive the actuator by pressure oil supplied from the hydraulic pump, the direction switching valve and the hydraulic cylinder A plurality of pilot check valves installed between the branch flow paths branched from the flow paths to open and switch the branch flow paths by a pilot operation, and the branch flow paths connected to the pilot check valve and the hydraulic cylinder small chamber. Installed between the flow path connecting In providing a heavy duty hydraulic circuit of the ballast, characterized in that to compensate for the load pressure provided with a means for maintaining the balance of the load pressure in the circuit.

Description

Hydraulic Balanced Circuit of Heavy Equipment

The present invention relates to a hydraulic balance circuit of heavy equipment, and more particularly, in the case of an excavator using a DOZER BLADE, the hydraulic balance of a heavy equipment to smoothly operate two or more hydraulic cylinders to operate the braid It is about a circuit.

In general, excavators, which are heavy equipment for construction, perform various works such as excavation work, cable work, landscaping work, earthwork laying work, and so on.

1 is a circuit diagram showing a hydraulic circuit of a general heavy equipment, the braid (1) operated by the pressure oil discharged from the hydraulic pump (P), and the flow path (2) between the above-described hydraulic pump (P) and the braid (1) (3) is installed in the direction change valve (4) for controlling the flow of the hydraulic oil by the pilot operation, and between the direction change valve (4) and the braid (1) to the hydraulic oil supplied from the hydraulic pump (P) First and second hydraulic cylinders (5) and (6) for actuating the braid (1) by means of which are provided between the above-mentioned directional valve (4) and the first and second hydraulic cylinders (5) and (6). It is provided, but is installed in the branch flow path (2a, 3a) (2b, 3b) branched from the above-described flow path (2) (3) to open and switch the branch flow path (2a, 3a) (2b, 3b) by pilot operation The circuit is controlled by controlling the pressure of oil discharged between the first and second pilot check valves 7 and 8 and the hydraulic pump P and the directional valve 4 described above. Consists of a relief valve (9) to call.

Looking at the operating state of the hydraulic circuit configured as described above, when the driver changes the direction change valve 4 of the neutral state to the second state (II), the pressure oil discharged from the hydraulic pump (P) is diverted through the flow path (3) Flows into the large chamber of the first and second hydraulic cylinders 5 and 6 via the valve 4, branch flow paths 3a and 3b and the first and second pilot check valves 6 and 7, respectively. At the same time the piston rod is extended to operate the braid (1).

By the way, when a difference in load pressure occurs in any of the first and second hydraulic cylinders 5 and 6, for example, the load pressure applied to the first hydraulic cylinder 5 is applied to the second hydraulic cylinder 6 side. When the load pressure is greater than the applied hydraulic pressure, the second hydraulic cylinder (6) having a lower load pressure is operated first, so that the first and second hydraulic cylinders (5) 6 and the braid 1 fixed mechanically Due to the operation of the hydraulic cylinder (6), the first hydraulic cylinder (5) is subjected to an easy load, so the first hydraulic cylinder (5) may not operate.

Accordingly, in order to solve the above problem, as shown in FIG. 2, another branch which interconnects branch passages 2a and 2b connected to the small chambers of the first and second hydraulic cylinders 5 and 6 is connected. The flow path 10 is further provided, and the orifice 11 is provided in this flow path, and the small chambers of the 1st and 2nd hydraulic cylinders 5 and 6 mutually communicated, and the load pressure difference applied to each small chamber was solved. .

However, a line implementing a conventional hydraulic balance circuit is connected by using a hose, and such a hose may be damaged by an external force or durability, and thus connected to the first and second hydraulic cylinders 5 and 6. If the braid (1) falls by its own weight and operates the equipment without knowing it, there is a problem of causing a safety accident such as overturning of the equipment.

In addition, the orifice 11 installed in the branch flow path 10 can be balanced against the load pressure in the first and second hydraulic cylinders 5 and 6, but this is a time that the driver can sense when the hose is damaged. Except for prolonging the ultimate problem has not been solved.

Therefore, the object of the present invention is to cancel the load pressure difference of the hydraulic cylinder to each other to perform the operation of the actuator smoothly, as well as to prevent the braid from falling due to its own weight even if the connected hose is damaged to offset the load pressure difference. It is to provide a hydraulic balancing circuit of heavy equipment which can be prevented.

1 is a circuit diagram showing a hydraulic circuit of a general heavy equipment,

2 is a circuit diagram showing a hydraulic balance circuit of a conventional heavy equipment;

Figure 3 is a circuit diagram showing a hydraulic balance circuit of the heavy equipment according to an embodiment of the present invention.

* Explanation of symbols for the main parts of the drawings *

P: Hydraulic Pump T: Hydraulic Tank

1: braid 2, 3: first and second flow paths

4: directional valve 5, 6: first and second hydraulic cylinders

7, 8: first and second pilot check valve 9: relief valve

20: fourth flow passage 21: cylinder housing

22: piston

The above-described object of the present invention, in the hydraulic balance circuit of heavy equipment, is installed in the actuator operated by the pressure oil discharged from the hydraulic pump, the flow path between the hydraulic pump and the actuator to open and switch the flow path by the pilot operation A plurality of hydraulic cylinders installed between the directional valve, the directional valve and the actuator to drive the actuator by pressure oil supplied from the hydraulic pump, and installed between the directional valve and the hydraulic cylinder, A plurality of pilot check valves installed in the branched branch flow paths for opening and switching the branch flow paths by a pilot operation, and installed between the flow paths connecting the pilot check valves and the branch flow paths connected to the hydraulic cylinder small chambers. Negative load in the circuit The heavy-duty hydraulic circuit of the ballast, characterized in that the provided means for maintaining a pressure equilibrium is achieved by providing.

According to a preferred feature of the present invention, the balancing means has a cylinder housing connected to one side and the other side to the flow path, and is installed in the cylinder housing so as to be double-acting, and moves in accordance with the load pressure difference in the small chamber, thereby increasing the load pressure. It is characterized in that the piston to offset.

Hereinafter, preferred embodiments of the present invention will be described based on the accompanying drawings.

3 is a circuit diagram showing a hydraulic balance circuit of the heavy equipment according to an embodiment of the present invention.

As shown in the figure, it is provided in the braid 1 which is operated by the hydraulic oil discharged from the hydraulic pump P, and the flow path 2 and 3 between the hydraulic pump P and the braid 1 mentioned above. The braid 1 is connected by a direction change valve 4 for controlling the flow of the hydraulic oil by pilot operation, and the pressure oil provided between the direction change valve 4 and the braid 1 and supplied from the hydraulic pump P. First and second hydraulic cylinders (5) and (6) are provided for operation, and are installed between the above-mentioned directional valve (4) and the first and second hydraulic cylinders (5) and (6), and the flow path (2) The first and second pilot check valves 7 which open and switch the branch flow paths 2a and 3a (2b and 3b) branched from the branch (3) by pilot operation. 8) and a relief valve 9 for controlling the pressure of the hydraulic oil discharged between the above-mentioned hydraulic pump P and the directional valve 4 to protect the circuit. The same reference numerals are given to the same elements, and detailed description thereof will be omitted.

Therefore, according to a preferred embodiment of the present invention, the branch flow passage connected to each of the small chambers of the first and second pilot check valves 7 and 8 and the first and second hydraulic cylinders 5 and 6 described above. Means are provided between the flow paths 20 which interconnect (2a) and (2b) to offset the load pressure in the circuit to keep the load pressure in the circuit balanced.

The above-described balancing means is installed in the cylinder housing 21 with one side and the other side connected to the above-described flow path 20 so as to be double-acting, and moved in accordance with the load pressure difference in the small chamber while being loaded. It consists of a piston 22 to cancel the pressure.

Hereinafter, the operation of the present embodiment configured as described above.

When the driver changes the direction change valve 4 in the neutral state to the second state (II) in order to perform a certain work, the hydraulic oil discharged from the hydraulic pump P passes through the flow path 3 to the direction change valve 4, Through the branch flow paths 3a and 3b and the first and second pilot check valves 7 and 8, they enter the large chambers of the first and second cylinders 5 and 6, and at the same time the piston rod is extended. Activate the braid (1).

On the other hand, when the load pressure acting in the small chamber of the 1st and 2nd hydraulic cylinders 5 and 6 is not the same, one side and the other side are connected to the flow path 20 branched from the branch flow paths 2a and 2b. The balancing means cancels the different load pressures in the small chambers of the first and second hydraulic cylinders 5 and 6 to maintain equilibrium. That is, when different load pressures are applied to each of the small chambers of the first and second hydraulic cylinders 5 and 6, the piston 22 in the cylinder housing 21 moves toward the side with less load pressure and at the same time a large load pressure. The cross-sectional area on this squeeze side naturally increases, reducing the load pressure. At this time, the piston 22 moves until the load pressure on the other side is the same, and cancels the load pressure in the cylinder housing 21 so that the load pressure is balanced. As such, when the load pressures in the small chambers of the first and second hydraulic cylinders 5 and 6 are equal to each other and the equilibrium state is reached, the piston 22 stops and always maintains the same pressure state in the hydraulic circuit. Will be.

As described above, the hydraulic balance circuit of the heavy machinery according to the present invention compensates the load pressure difference of the hydraulic cylinders with each other so that the operation of the actuator is performed smoothly, and even if one line is damaged, the actuator is fixed by the other cylinder. It is possible to prevent the fall of the actuator by its own weight, there is an effect that the safety accident is prevented in advance.

Claims (2)

In the hydraulic balance circuit of heavy equipment: An actuator operated by the pressurized oil discharged from the hydraulic pump; A direction switching valve installed in a flow path between the hydraulic pump and the actuator to open and switch the flow path by a pilot operation; A plurality of hydraulic cylinders installed between the directional valve and the actuator to drive the actuator by pressure oil supplied from the hydraulic pump; A plurality of pilot check valves installed between the direction switching valve and the hydraulic cylinder, the plurality of pilot check valves installed in the branch flow path branched from the flow path to open and switch the branch flow path by a pilot operation; And And a means installed between the pilot check valve and the branch passage connected to the hydraulic cylinder small chamber to offset the load pressure in the circuit to maintain the load pressure in the circuit in a balanced manner. Hydraulic balanced circuit. The method according to claim 1, wherein the balancing means, A cylinder housing having one and the other side connected to the flow path, Hydraulically balanced circuit of the heavy equipment is installed in the cylinder housing to be double-actuated, the piston is provided to cancel the load pressure while moving in accordance with the load pressure difference in the small chamber.