JPS6250683B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a flow rate regulating device with a pressure compensation function.

Conventionally, a flow rate regulating valve with pressure compensation, as shown in Figs. 1 and 2, is provided with a flow rate regulating throttle c operated by a handle b and a compensator spool e sprung by a spring d in a valve casing a. A device in which the flow rate of the fluid flowing from the inlet f to the outlet g is adjusted is known, but in this type of device, the flow rate of the fluid from the inlet f to the outlet g is controlled by operating a switching valve in front of the flow rate regulating valve. Even if the flow rate disappears, the flow path from the inlet e to the outlet g remains in communication, so if the flow again flows from the inlet f next time, there will be a delay in the operation of the compensator spool e. The instantaneous excessive flow rate is undesirable. This instantaneous excessive flow (jumping phenomenon)
In order to prevent this, as seen in Japanese Patent Publication No. 47-27853, a piston with a push rod is attached to the compensator spool of the flow rate regulating valve, and the piston is urged by a spring to close the gap between the compensator spool and the bush. It is known that the valve is closed and the piston is moved back against the spring by the pressure at the inlet of the flow rate regulating valve. However, the provision of such a piston and spring complicates the structure of the flow rate regulating valve, and the spring that pushes the piston must be stronger than the control spring that urges the compensator spool. Therefore, the pressure for retracting the piston against the spring, that is, the operation start pressure for starting the pressure compensation operation, becomes high, which has the drawback that the control pressure range of the compensator becomes narrower.

Furthermore, as seen in Japanese Patent Publication No. 51-14665, a pressure compensating valve is provided in front of the switching valve near the pump, and when the switching valve is closed, the compensator spool of the pressure compensating valve is connected to the outlet side of the switching valve. It is also known that the oil passage is operated to close by the pump pressure in the oil passage between To prevent this, it is necessary to specifically provide a throttle valve in the switching valve, which has the disadvantage of complicating the structure of the switching valve.

The purpose of the present invention is to prevent the jumping phenomenon without causing such drawbacks.
A circuit connecting the hydraulic pump and the actuator includes a valve housing having an inlet connected to the pump, an outlet connected to the actuator, and a flow path connecting these inflow and outlet, and a flow rate adjustment throttle provided in the flow path. In a device that is equipped with a flow rate regulating valve having a compensator spool that is actuated by the force due to the pressure difference before and after the flow rate regulating throttle and the force of a spring to throttle the flow path, The circuit is provided with a directional switching valve type opening/closing control valve that opens and closes the circuit and shuts off the pump port in the neutral position, and a flow rate adjustment throttle is disposed near the inlet of the flow rate adjustment valve, and A compensator spool is arranged near the rear outlet, and the pressure of the circuit closer to the pump than the opening/closing control valve is used as the pressure in front of the flow rate adjustment throttle of the flow rate adjustment valve to counteract the force of the spring of the compensator spool. The feature is that a pressure introduction circuit is provided to guide the pressure. It is characterized by having the following.

One example of the present invention is shown in FIGS. 3 and 4, in which 1 is a valve housing of a flow rate regulating valve, 2 is a hollow flow rate regulating throttle equipped with a throttle hole 3, and 4 is a variable Hollow compensator spool with aperture 5,
6 indicates an inlet, and 7 indicates an outlet. The flow rate adjusting throttle 2 is arranged near the inlet 6 in the valve housing 1 and close to the outlet 7 behind it, and the flow rate adjusting throttle 2 and the compensator spool 4 It was housed in a hollow cylinder 8 provided in a flow path connecting the inlet 6 and the outlet 7 so as to be slidable via a spring 9. Furthermore, a pressure introduction circuit 11 is formed in the valve housing 1, which is connected to the end surface of the compensator spool 4 opposite to the spring 9 via a throttle 10. When pressure fluid is introduced into this, the spool 4 is connected to the variable throttle. 5
can be operated to the closed side. Reference numeral 12 denotes a handle for moving the flow rate adjusting throttle 2 and adjusting the opening degree of the throttle hole 3. The flow rate regulating valve is provided in a circuit 16 connecting a hydraulic pump 14 and a hydraulic actuator 15, as shown in the fourth figure, its inlet 6 is connected to the pump 14, and its outlet 7 is connected to the actuator 15. Further, an on-off control valve 13 for opening and closing the circuit 16 is provided at a position closer to the pump than the flow rate adjustment valve of the circuit 16, and the pressure of the circuit 16 that is further closer to the pump than the on-off control valve 13 is guided to the pressure introducing circuit 11. I did it like that. As the opening/closing control valve 13, a directional control valve type is used which controls the operating direction of the actuator 15, which has a neutral position that interrupts the circuit from the pump 14 to the flow rate regulating valve. The compensator spool 4 of the flow rate adjustment valve is actuated by the force of the pressure difference before and after the flow rate adjustment throttle 2 and the force of the spring 9 to throttle the flow path from the inlet 6 to the outlet 7. Since the pressure near the pump of the on-off control valve 13 of the circuit 16 is introduced as the front pressure, when the on-off control valve 13 is in the position (A) (a) where the circuit 16 is opened, the fluid from the pump 14 is flows from the inlet 6 to the outlet 7 connected to the actuator 15 via the throttle hole 3 of the flow rate adjustment throttle 2 and the variable throttle 5 of the spool 4. At this time, the compensator spool 4 It moves to a position where the force due to the pressure behind the flow rate adjustment throttle 2 and the force due to the pressure near the pump of the on-off control valve 13 of the circuit 16 acting on the other side are balanced, performing a pressure compensation action, and furthermore, the on-off control valve 13 is moved to the position 13b that closes the circuit 16 and the inflow flow to the inlet 6 disappears, the spool 4 is moved against the spring 9 by the pump discharge pressure introduced via the pressure introduction circuit 11. Since the variable throttle 5 is moved, the variable throttle 5 is closed, and the inlet 6 and outlet 7 are closed.
Communication with the device is cut off. Furthermore, when fluid is caused to flow into the inlet port 6 again by operating the on-off control valve 13, the spool 4 can be activated immediately by the force of the spring 9 even if the pressure is low, and the variable throttle 5 gradually opens from the closed state. So the excess flow is at the outlet 7.
It never flows. 17 is a check valve for backflow.

As described above, the present invention has an on-off control valve that shuts off the circuit in the neutral position near the pump of the circuit connecting the inlet of the flow rate adjustment valve and the pump, and a flow rate adjustment throttle close to the inlet of the flow rate adjustment valve. At the same time, a compensator spool was provided behind the outflow port, and the pressure of the circuit closer to the pump than the on-off control valve was led to the compensator spool, so that when the inflow to the inlet ran out, the compensator spool The spool remains in the closed state to prevent excessive flow from passing through when the next flow rate flows in, and the compensator spool can be brought into the closed state by directly applying fluid pressure without using any special equipment. Even at a low inflow pressure, the pressure compensation operation can be started by the spring from the closed state, and there are effects such as the ability to obtain a flow rate adjustment device with good low pressure controllability at a low cost.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional side view of a conventional example, FIG. 2 is a cross-sectional plan view thereof, FIG. 3 is a cross-sectional view of an example of the present invention, and FIG. 4 is a line diagram of the state of use. DESCRIPTION OF SYMBOLS 1... Valve housing, 2... Flow rate adjustment throttle, 4... Compensator spool, 6... Inflow port, 7... Outlet port, 9... Spring, 11... Pressure introduction circuit, 13...
...opening/closing control valve, 14...pump, 15...actuator, 16...circuit.

Claims (1)

[Claims] 1. A circuit connecting a hydraulic pump and an actuator includes a valve housing having an inlet connected to the pump, an outlet connected to the actuator, and a flow path connecting these inlets and the outlet, and a flow rate adjustment throttle provided in the flow path. and a compensator spool that is actuated by the force due to the pressure difference before and after the flow rate adjusting throttle and the force of a spring to throttle the flow path, the flow rate adjusting valve being closer to the pump than the flow rate adjusting valve. A directional control valve type opening/closing control valve that opens and closes the circuit and shuts off the pump port in the neutral position is provided in the circuit, and a flow rate adjustment throttle is disposed near the inlet of the flow rate adjustment valve, and a flow rate adjustment throttle is disposed near the inlet of the flow rate adjustment valve. A compensator spool is placed near the outlet at the rear of the circuit, and the pressure in the circuit, which is closer to the pump than the opening/closing control valve, is used as the pressure in front of the flow rate adjustment throttle of the flow rate adjustment valve to counteract the force of the spring of the compensator spool. A flow rate adjustment device characterized by being provided with a pressure introduction circuit that guides the flow to the desired level.