JPS58102803A - Fluid control circuit device - Google Patents

Abstract

PURPOSE:To prevent a resonance of a valve in an oil pressure circuit by a method wherein when an actuator operates in a direction in which load changes occur, a return flow amount from the actuator is squeezed. CONSTITUTION:When the actuator 2 operates in the direction in which load changed are apt to occur, the return flow amount from the actuator 2 to a tank 13 is squeezed by a throttle 14 provided at a changeover valve 6. In this instance, with the inflow amount into the actuator 2 not squeezed in order not to operate a pressure compensating valve 5, the flow amount through the oil pressure circuit 3 is controlled by a counterbalance valve 10 and a relief valve 11, thereby enabling a stable flow amount control even when changes occur in the load.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a flow control circuit device for driving an actuator with load fluctuations.

Conventionally, a flow rate control circuit device for an actuator with load fluctuations such as a wine chain includes, for example, a pressure compensation valve 1 and a switching valve with a flow rate control function as shown in FIG. A hydraulic circuit e is known.

If the switching valve b1 is operated to the off position, the actuator will operate to lift the load, and if the switching valve b1 is operated to position bK, it will operate to lower jlIL#i, but in this case *# If you suddenly operate the switching valve to lower the crane while it is being held, the circuit pressure will suddenly change (due to load fluctuations) and the pressure compensation valve 1 and the locking lance valve will
There is an inconvenience that there is resonance between the two. This resonance can be somewhat eliminated by lowering the set pressure of the relief valve C, but since the flow rate to the actuator g whose lacrimal volume is controlled is discharged through the 17 + 7 valve C, the flow rate control 1 function is The drawbacks of Tsukuda are obvious.

The invention aims to solve these drawbacks, and is equipped with a pressure compensating valve and a switching valve with flow rate control, as well as a relief valve and a control valve. In a device that drives an actuator that causes fluctuations in the flow rate, the flow rate control cut-off valve is provided with a throttle valve that throttles R1 of sb from the actuator when the a actuator operates in one direction. It is set up.

An example of the device of the present invention will be explained with reference to the drawings, as shown in FIG.
(1) is a hydraulic source, (2) is an actuator such as a Quinte hydraulic motor that can cause load fluctuations when operating in one direction. (3) is a hydraulic circuit that drives the actuator, and Ws hydraulic circuit. (3) lds hydraulic IIf (1)
A pressure-compensated switching valve with flow rate control obtained by integrally configuring a pressure compensation valve (5) interposed in a pressure oil supply circuit (4) connected to the pressure oil supply circuit (4) and a switching valve with flow rate control (6) downstream thereof. Valve (7
), and 2 connecting the switching valve (7) and the actuator (2).
Each of the two valves (1G) and the relief valve (11) intervenes in each case.

When the switching valve (6) is operated to its switching position (6m) K, the pressure oil supply circuit (4) is connected to the circuit (8), and the actuator (2) lifts, for example, a load.

When the neutral position (6b) K is operated, the cacuntano intake valve (lO) operates to hold the load, and when the other switching position (6c) K is switched, the actuator (2) reverses and lowers the load.

Further, the switching valve (6) is located at the fishing switching position (61).
) to restrict the inflow flow to the actuator (2).
(t2), and is configured to perform simeter-in control by cooperating with this and a pressure compensation valve (5).

The above configuration is almost the same as that of the conventional flow control circuit device, but in the uninvented one, the flow rate control circuit device is operated in one direction, which tends to cause fluctuations in the load of the actuator (2).
) to the tank (13) is set in the switching valve (6) by restricting it from the nine restrictor (14) fc.In this case, the pressure compensating valve ( 5) is not activated, and the flow rate of the hydraulic circuit (3) is controlled by the control valve (lO) and the relief valve (lO).
1) to ensure stable flow rate control in the event of negative itI fluctuations. In other words, when the actuator (2) in the face direction, which is responsible for load fluctuations, operates, the pressure compensation valve (5) does not operate, and the Kaku/Tano 9 lance valve (l) does not operate.
Since the pressure in the pilot circuit (15) is determined by the set pressure of the relief valve (11), the pressure in the pilot circuit (15) is stable without being affected by load fluctuations.

To clarify its operation, the switching valve (6) is suddenly moved to the position (6
C) and lower the load, when the oil pressure dl
The flow from (1) is not throttled and is transferred to actuator (2) K.
The excess flow rate is removed by the relief valve (11), but the 5th circuit (9) is throttled by the throttle (14), and the differential pressure between them is equal to or less than the set pressure of the relief valve (rti). Recognizing the operating pressure of the valve (1G), the pressure remains approximately constant.Thus, as shown by #llA in Fig. 34, the main pilot circuit (15)K is set to the set pressure of the relief valve (11). When the pressure is applied and a relatively stable pressure is generated, the control pressure of the counter lance valve (lO) also becomes line B.
It stabilizes as shown in . Figure 4 shows the control properties of the conventional device shown in Figure 1, in which the upper limit of the pressure in the pilot circuit is the sum of the set pressure of the relief valve and the back pressure. As a result, the stability is poor, and along with this, s
＠ - The control pressure of the 2nd ounce valve is unstable, and the previously controlled 9 flows are again removed by the relief valve, which lacks the integration of flow rate control and is like an uninvented thing. Good stability and flow control cannot be obtained.

When the actuator operates in one direction, which causes load fluctuations, the return flow rate from the Kfi actuator is throttled. This has the effect of preventing and improving flow rate control 1Q accuracy.

[Brief explanation of drawings]

Fig. 1 is a #1 diagram of a conventional flow rate control circuit device, Fig. 2 is a scale diagram of an example of the device of the present invention, and Fig. 3 is a control characteristic curve diagram thereof. This is Figure 11. (2)...Actuator (3)...Hydraulic circuit (
5)...Pressure compensation valve (6)...Switching valve with flow rate control (10)...Kakunta balance valve (11)...
Relief valve (14)... Patent applicant for the throttle Uchida Hydraulic Xu - Agent for Kogyo Co., Ltd. Kin Kitamura - Pseudonym 4th figure 3rd figure

Claims (1)

[Claims] Nine hydraulic circuits are equipped with a pressure compensation valve, a switching valve with flow rate control, a relief valve and a kakunta balance valve (to drive an actuator that causes load fluctuations when operating in one direction). , a flow rate control circuit device comprising, in the flow rate control switching valve, a throttle that throttles the flow rate of the return pipe from the actuator when the actuator operates in the one direction;