KR20030052723A - hydraulic apparatus for construction heavy equipment - Google Patents

Abstract

PURPOSE: A variable flow control apparatus for heavy construction equipment is provided to improve the reliability by increasing responsiveness in restricting counter flow by increasing load pressure of the actuator more than discharge pressure of the hydraulic pump, and to stabilize the hydraulic system and reduce expenses by simplifying the structure. CONSTITUTION: A seat valve body is installed in the passage between a pump path(5) and a feeder path to control flow to a load passage by regulating flow to a variable throttle. The seat valve body comprises a first seat valve(502) moving according to pressure difference between load pressure of the load passage and discharge pressure of a hydraulic pump, and having a variable control throttle varying the opening area from the pump path to the feeder path, a second seat valve(501) having a variable pilot control throttle(512) moving against the first seat valve in supplying pilot pressure, and changing the opening area according to the movement, and a pilot spool(41) having a variable pilot throttle(525) deciding movement of the variable pilot control throttle of the second seat valve in applying the pilot signal pressure.

Description

Variable apparatus for construction heavy equipment

The present invention is to provide a variable flow control device for heavy construction equipment to control the flow rate supplied to a specific actuator that generates a lot of load during operation by using a pilot signal pressure by using a heavy construction equipment such as an excavator using a plurality of actuators It is about.

More specifically, the non-return check valve used when the load pressure generated in an actuator such as a hydraulic cylinder is higher than the discharge pressure of the hydraulic pump is excellent in response, and is structurally simple, making it easy to manufacture and improving the stability of the hydraulic system. It relates to a variable flow control device that can be secured.

1 to 3, the variable flow control apparatus according to the prior art, the operating pressure supplied from the pump passage (5) to the pair of main variable throttles (16A, 16B) through the feeder passage (7) Directional control valves 100A and 101A for controlling the flow rate of the valve and assisting the flow rate of the operating pressure flowing into the pair of load passages 6A and 6B,

Seat valves 300 and 301 which are installed to move in the housing 1 and form an auxiliary variable throttle 28 in the feeder passage 7, and control variable throttles which change the opening area according to the movement amount of the seat valves 300 and 301 ( A seat valve body 20 having 28),

The upstream side 7C from the auxiliary variable throttle 28 of the feeder passage 7 is connected to the downstream side 7A, 7B of the feeder passage 7 via the control variable throttle 33, and Pilot lines 24, 29 to 31, 35 to 37 for determining the movement amount of the valve body 20,

The pilot variable throttle 45 and the flow control signals 802 and 803 provided in the pilot lines 35 and 36 change the opening area of the pilot variable throttle 45 to control the pilot signal pressure flowing through the pilot lines 35 and 36. It is configured to include a pilot flow control valve 400.

Accordingly, as the flow control valve 200B is switched to the left or right direction in the drawing of FIG. 2 according to the application of the pilot signal pressures P2a and P2b, the flow control valve is discharged from the hydraulic pump 200 and switched. When driving the hydraulic motor 701 by the operating pressure supplied via the 200B, the hydraulic cylinder 702 via the flow control valve 200A switched according to the application of the pilot signal pressures P1a and P1b. It is possible to proportionally control the flow rate of the working pressure supplied to.

However, since the aforementioned pilot flow control valve 400 is always maintained in the initial state opened, the load pressure of the hydraulic cylinder 702 of the hydraulic cylinder 702 occurs higher than the discharge pressure of the hydraulic pump 700. In this case, the operating pressure set to the actuator 702 is not supplied due to the reverse flow of the seat valve 300, so that an accident risk may occur because of an uncontrollability. As shown in FIG. 4, the inside of the seat valve 301 is prevented. Although separately installed the non-return check valve 122, this also has a problem in that the responsiveness is prevented when the reverse flow is prevented, the reliability of the equipment is lowered, and the manufacturing cost is increased due to the increase in the number of parts.

Accordingly, an object of the present invention is to provide a variable flow control device for heavy construction equipment, which has a higher load pressure on the actuator side than a discharge pressure of a hydraulic pump, so that the response can be improved and the reliability can be improved when performing the non-return check function. It is.

Another object of the present invention is to provide a variable control device which can simplify the structure to reduce the manufacturing cost and ensure the stability of the hydraulic system.

1 is a hydraulic circuit diagram of a variable flow control apparatus according to the prior art,

2 is a cross-sectional view of a variable control apparatus according to the prior art,

3 is an excerpt of the main portion of the seat valve according to the prior art,

Figure 4 is another modified example of the seat valve according to the prior art,

5 is a hydraulic circuit diagram of a variable flow control apparatus according to an embodiment of the present invention;

6 is a cross-sectional view of a variable flow control apparatus according to an embodiment of the present invention,

7 is a cross-sectional view of a pilot check valve according to another embodiment of the present invention.

Explanation of symbols used in the main part of the drawing

2; Pilot flow control valve 3; Spool

5; Pump passages 6A, 6B; Load passage

7; Feeder passages 7A, 7B; Downstream passage

7C; Upstream passage 41; Pilot split

100A; Direction switching valve 500; Seat valve body

501,502; Seat valves 511,512; Control variable throttle

521,522; Pilot flow path 524; Pressure chamber

700; Hydraulic pumps 702,703; Hydraulic cylinder

An object of the present invention described above, the actuator connected in parallel to the pump passage of the hydraulic pump and the drive, and the flow rate control valve is installed in the flow path between the hydraulic pump and the actuator is switched when the pilot signal pressure is applied to control the flow of the working oil and In the flow path between the pump passage and the feeder passage is installed in the flow control device for heavy equipment under construction comprising a seat valve body for controlling the flow rate supplied to the variable throttle and auxiliary control of the flow rate flowing into the load passage 500,

In the flow path between the pump passage (5) and the feeder passage (7) is installed to move by the load pressure of the load passage (6A, 6B) and the pressure of the discharge side of the hydraulic pump (700), the pump passage (5) in accordance with the movement amount A first seat valve (502) having a control variable throttle (511) for varying the opening area from the to the feeder passage (7),

The second seat valve having a pilot control variable throttle 512 which moves relative to the first seat valve 502 to determine the movement amount of the first seat valve 502 and changes the opening area according to the movement amount when the pilot pressure is supplied. 501),

For pilot heavy equipment, characterized in that it comprises a pilot spool 41 having a pilot variable throttle 525 which is switched when the pilot signal pressure is applied to determine the amount of movement of the pilot control variable throttle 512 of the second seat valve 501. By providing a variable flow control device.

According to a preferred embodiment, between the pilot signal pressure passages 522a and 523 so as to prevent the load pressure in the load passages 6A and 6B from flowing back into the pump passage 5 when driving the above-described hydraulic cylinder 702. A check valve 550 for preventing the back flow is installed.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings, which are intended to be described in detail so that those skilled in the art to which the present invention pertains can easily carry out the present invention. It does not mean that the technical spirit and scope are limited.

5 and 6, the hydraulic pump 700, the actuator (701, 702, 703) connected and driven in parallel to the pump passage (5) of the hydraulic pump 700, the hydraulic pump 700 and the actuator ( Flow control valves 200A, 200B and 200C installed in the flow path between 701, 702 and 703 to control the flow direction of the hydraulic oil to be switched when the pilot signal pressure is applied to start, stop and redirect the actuators 701, 702 and 703, and pump passages ( 5) Seat valve body 500 is installed in the flow path between the feeder passage (7) to control the flow rate supplied to the variable throttle (16A, 16B) and to control the flow rate flowing into the load passage (6A, 6B) Applied to the flow control device for construction equipment having a.

Therefore, according to the preferred embodiment of the present invention, the above-described seat valve body 500, the load pressure and the hydraulic pressure of the load passage (6A, 6B) in the flow path between the pump passage (5) and the feeder passage (7) described above The pump 700 is installed to move by the pressure difference on the discharge side, and the first seat valve 502 having a control variable throttle 511 for changing the opening area from the pump passage 5 to the feeder passage 7 according to the movement amount. Wow,

A second having a pilot control variable throttle 512 which determines the movement amount of the first seat valve 502 according to the movement based on the first seat valve 502 when the pilot pressure is supplied, and changes the opening area according to the movement amount; Seat valve 501,

And a pilot spool 41 having a pilot variable throttle 525 that is switched when the pilot signal pressure is applied to determine the amount of movement of the pilot control variable throttle 512 of the second seat valve 501.

In this case, as shown in FIG. 7, the pilot signal pressure passages 522a, 522a, may be prevented to prevent the load pressure in the load passages 6A and 6B from flowing back into the pump passage 5 when the hydraulic cylinder 702 is driven. A check valve 550 for preventing backflow is installed between the points 523.

Reference numeral 1 is a housing, and 800 is a relief valve that maintains and protects the set operating pressure in the circuit.

Hereinafter, the operation of the variable flow control device for construction equipment according to the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIGS. 5 and 6, the upstream side passage of the feeder passage 7 through the control variable throttle 512 is arranged in the upstream side passage 7C than the auxiliary variable throttle 511 of the feeder passage 7 described above. 7A and 7B, the seat valve body 502 is moved by the pressure difference in the pair of load passages 6A and 6B and the pressure in the upstream passage 7C of the hydraulic pump 700. The passage through the control variable throttle 512 is connected to the pilot passage 521 of the pilot flow control valve 2, while the pilot passage 521 remains closed with the pilot connection passages 523, 522a and 522. The pilot spool 41 has a variable throttle 525 that varies with the amount of movement.

Therefore, when the pilot signal pressure 531 is not applied, the seat valve body 502 has a difference between the load pressure in the load passages 6A and 6B and the pressure difference in the upstream passage 7C of the hydraulic pump 700. Since it is switched by, the upstream passage 7C and the downstream passage 7A of the feeder passage 7 without time delay even when the pressure in the load passages 6A and 6B becomes higher than the discharge pressure in the hydraulic pump 700. By blocking between 7B), even when a high load occurs in the hydraulic cylinder 702, it can be controlled.

As shown in FIG. 6, when the hydraulic motor 701 is driven or to limit the flow rate of the working pressure flowing into the hydraulic cylinder 702 for driving another hydraulic cylinder 702 having a large load, the pilot signal pressure ( The pilot spool 41 is moved in the left direction in proportion to the size of the 531. At this time, the blocked pilot flow paths 522 and 521 are opened through the variable throttle 525 of the pilot spool 41. The pilot pressure acts on the pressure chamber 524 through 523, 522a, 522, 521, and the condition of the opening amount of the variable throttle 525 of the pilot spool 41 and the opening amount of the pilot control variable throttle 512 Since the seat valve 501 is moved downward in the drawing so as to be proportional to each other, it is possible to limit the upward movement of the seat valve 502.

Therefore, the flow rate of the operating pressure from the upstream passage 7C of the hydraulic pump 700 to the feeder passage 7 can be adjusted by controlling the movement amount of the seat valve 502.

As mentioned above, according to a preferable embodiment, it has the following advantages.

Since the load pressure on the actuator side is higher than the discharge pressure of the hydraulic pump, the response can be improved and the reliability can be improved when performing the non-return check function.

In addition, by simplifying the structure is easy to manufacture, it is possible to lower the cost and manufacturing cost, to ensure the stability of the hydraulic system.

Claims (2)

Actuator connected and driven in parallel to the pump passage of the hydraulic pump, flow control valve installed in the flow path between the hydraulic pump and the actuator to be switched when the pilot signal pressure is applied to control the flow of hydraulic fluid, between the pump passage and the feeder passage In the flow control device for construction equipment having a seat valve body installed in the flow path to control the flow rate supplied to the variable throttle and auxiliary control the flow rate flowing into the load passage: The seat valve body 500 is; In the flow path between the pump passage (5) and the feeder passage (7) is installed to move by the load pressure of the load passage (6A, 6B) and the pressure of the discharge side of the hydraulic pump (700), the pump passage (5) in accordance with the movement amount A first seat valve 502 having a control variable throttle 511 for changing the opening area from the feeder passage 7 to the feeder passage 7; A second seat valve having a pilot control variable throttle 512 which moves with respect to the first seat valve 502 to determine the movement amount of the first seat valve 502 and changes the opening area according to the movement amount when the pilot pressure is supplied ( 501); And For pilot heavy equipment, characterized in that it comprises a pilot spool 41 having a pilot variable throttle 525 which is switched when the pilot signal pressure is applied to determine the amount of movement of the pilot control variable throttle 512 of the second seat valve 501. Variable flow control device. 2. The back flow between the pilot signal pressure passages 522a and 523 so as to prevent the load pressure in the load passages 6A and 6B from flowing back to the pump passage 5 when the hydraulic cylinder 702 is driven. Preventive check valve 550 is a variable flow control device for construction equipment, characterized in that installed.