JP2631310B2 - Pressure regulating valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Objects of the Invention (1) Field of Industrial Application The present invention relates to a pressure regulating valve for regulating the pressure of a high pressure section of various fluid pressure circuits, and particularly to an inlet and a low pressure section connected to a high pressure section. A piston box having an outlet communicating with the piston, a piston valve slidably housed in the valve box to open and close the outlet, and partitioning the interior into a pressure receiving chamber and a spring chamber communicating with the inlet and the outlet, The present invention relates to an improvement of a pressure regulating valve including a pressure regulating spring housed in a spring chamber to bias a valve in a valve closing direction against a valve opening force due to a pressure receiving chamber pressure.

(2) Prior Art The pressure regulating valve as described above is widely used as a relief valve for regulating the discharge pressure of a hydraulic pump to a constant value.

(3) Problems to be Solved by the Invention In the conventional pressure regulating valve, there is hysteresis in the opening / closing operation of the piston valve. That is, the valve closing pressure at which the piston valve closes when the pressure in the pressure receiving chamber gradually decreases in the open state becomes lower than the valve opening pressure at which the piston valve opens when the pressure in the pressure receiving chamber gradually increases. That is, when the pressure receiving chamber is depressurized, the piston valve delays closing. Such hysteresis is caused by the friction of each part of the piston valve, the force that interrupts the flow of fluid, the delicate pressure balance of each part, and the like, and causes the pressure of the high-pressure part to be regulated to fluctuate.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide the above-mentioned pressure regulating valve which equalizes the valve opening pressure and the valve closing pressure of the piston valve.

B. Configuration of the Invention (1) Means for Solving the Problems In order to achieve the above object, the present invention relates to a piston valve, which is arranged such that a piston valve approaches an outlet from outside a valve box when the piston valve is opened. A reaction plate that receives pressure flowing out of the plate is provided continuously.

(2) Operation According to the above configuration, when the piston valve is opened, the outflow pressure from the outlet acts on the reaction plate as an appropriate closing force. Alleviated or eliminated. Thereby, the valve opening pressure and the valve closing pressure of the piston valve can be equalized.

(3) Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings. First, in FIG. Feed to Road 3. The pressure oil sent to the high-pressure channel 3 is supplied to the hydraulic device 4 to operate it. The high-pressure flow path 3 is connected to a relief valve 5 as a pressure adjusting valve for adjusting the pressure to a constant value. During the pressure adjustment, the oil flowing out of the relief valve 5 is returned to the oil reservoir 2.

As shown in FIG. 2, the relief valve 5 includes a valve box 10, a piston valve 11 slidably housed in the valve box 10, and a pressure regulating spring 12 as main components.

The valve box 10 has a cylindrical shape, and has an inlet 13 connected to the high-pressure flow path 3 on a side wall, and an outlet 14 opened to the oil reservoir 2 on one end wall. The inside of this valve box 10 is provided with a pressure receiving chamber 15 connected to an inlet 13 and an outlet 14 by the piston valve 11.
And a spring chamber 17 communicating with the atmosphere via a vent hole 16.

The piston valve 11, a valve portion 11a that can open and close the outlet 14,
A piston portion 11b that receives the pressure of the pressure receiving chamber 15 as a valve opening force,
And a flange portion 11c which abuts on an end wall of the spring chamber 17 to define a fully closed position base of the piston valve 11. In order to urge the piston valve 11 in the closing direction, the pressure regulating spring 12 is
To be housed.

The above is the conventional configuration, and the present invention further has the following configuration.

That is, a thin shaft 18 extending to the outside of the outlet 14 is integrally formed on the end face of the piston valve 11 on the valve portion 11a side, and a reaction plate 19 facing the outlet 14 is connected to the tip. The reaction plate 19 approaches the outlet 14 in response to the valve-opening operation of the piston valve 11, but does not close the outlet 14.

 Next, the operation of this embodiment will be described.

As shown in FIG. 2, when the piston valve 11 is closed,
When the pressure introduced from the high-pressure flow path 3 into the pressure receiving chamber 15 gradually increases to exceed a predetermined value while the outlet 14 is closed by 11a, the valve-opening force applied to the piston portion 11b by the pressure is adjusted by the pressure regulating spring 12b. The set load is overcome to move the piston valve 11 in the valve opening direction, and the valve portion 11a opens the outlet 14 as shown in FIG. The reaction plate 19 approaches the outlet 14 as the piston valve 11 opens.

When the outlet 14 opens, the pressure oil in the pressure receiving chamber 15 flows from the outlet 14 to the oil sump 2.
The pressure in the high-pressure flow path 3 is reduced by flowing out of the high-pressure flow path 3.

By the way, since the reaction plate 19 is close to the exit 14,
The pressure oil flowing out of the outlet 14 exerts an outflow plate P on the reaction plate 19 to give an appropriate valve closing force. This moderate closing force compensates for the difficulty of closing the piston valve 11 due to hysteresis.

Therefore, during the opening of the piston valve 11, when the pressure in the pressure receiving chamber 15 gradually decreases to a certain value due to the outflow of the pressure oil, the piston valve
In 11, the valve closing operation is started immediately by the force of the pressure adjusting spring 12 and the valve closing force received by the reaction plate 19 to close the outlet 14.

Thus, the valve opening pressure and the valve closing pressure of the piston valve 11 are equalized, and the pressure in the high-pressure flow path 3 can be adjusted to a constant value without fluctuation.

C. Effects of the Invention As described above, according to the present invention, when the piston valve is opened, the reaction plate that approaches the outlet from the outside of the valve box and receives the outflow pressure from the outlet is connected to the piston valve. Therefore, in the open state of the piston valve, the closing delay of the piston valve can be reduced or eliminated by the valve closing force received by the reaction plate from the outflow pressure, thereby equalizing the valve opening pressure and the valve closing pressure of the piston valve. Thus, the pressure of the high-pressure section can be accurately adjusted.

[Brief description of the drawings]

The drawings show an embodiment of the present invention. FIG. 1 is a hydraulic circuit diagram, FIG. 2 is a longitudinal sectional view of the relief valve according to the present invention in the hydraulic circuit, and FIG. 3 is an explanation of the operation of the relief valve. FIG. p Outflow pressure, 2 Oil reservoir as low pressure section, 4 Relief valve as pressure regulating valve, 10 Valve box, 11 Piston valve, 12 Pressure regulating spring, 13 Inlet , 14 ... Exit, 15
…… Pressure receiving chamber

Claims (1)

(57) [Claims] 1. A valve housing having an inlet connected to a high pressure portion and an outlet connected to a low pressure portion, and a pressure receiving chamber slidably housed in the valve housing to open and close the outlet, the interior of which is connected to the inlet and the outlet. A pressure regulating valve comprising a piston valve partitioned into a spring chamber and a pressure regulating spring housed in the spring chamber to urge the piston valve in a valve closing direction against a valve opening force caused by the pressure of the pressure receiving chamber. The pressure regulating valve according to any one of claims 1 to 3, characterized in that a reaction plate is connected to the piston valve to open the piston valve and to receive an outflow pressure from the outlet by approaching the outlet from outside the valve box.