JP2813111B2 - Valve device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve device.

[0002]

2. Description of the Related Art As shown in FIG. 3, a pilot valve 3 is connected to a pilot pressure operating section 2 of a main valve 1 and a pilot signal such as air supplied from a fluid pressure source 4 through the pilot valve 3 is transmitted. By switching the main valve 1 during use, a large flow rate of fluid is supplied through the main valve 1.

[0003]

The pilot valve 3 can switch the main valve 1 by generating a pilot pressure even with a minute displacement, but a minute displacement alone can supply a large amount of fluid instantaneously. If only this is used to control the fluid supply to the pneumatic pump,
The problem of poor switching such as the reciprocation of the pump being stopped at the neutral position occurs.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to solve the switching failure or the like generated by a pump by enabling a large amount of fluid to be supplied instantaneously with only one valve device. Is what you do.

[0005]

SUMMARY OF THE INVENTION According to the present invention, there is provided a valve apparatus in which a poppet valve body is provided so as to be able to freely contact and separate at a fluid inlet side with respect to a valve seat formed between a fluid inlet and a fluid outlet formed in a valve body. An axially movable valve shaft which is provided integrally with the poppet valve body and extends to the opposite side via the valve seat from the poppet valve body, and which is fitted to the peripheral surface of the valve shaft and has a valve body side. A seal member that applies a resisting force to the axial movement of the valve shaft due to friction with the member, and a spring that abuts on the shaft end of the valve shaft and applies an axial force accumulated by an external displacement to the valve shaft. It is a valve device of a configuration provided.

[0006]

According to the present invention, when there is no external displacement, the poppet valve body closes the valve seat by the axial force in the closing direction due to the fluid pressure acting on the poppet valve body. Further, the axial force in the opening direction acting on the valve shaft is increased from the spring accumulated by the displacement from the outside, and this spring force is the axial force in the closing direction due to the fluid pressure acting on the poppet valve body and the maximum static friction acting on the seal member. When the resultant force exceeds the resultant force, the poppet valve element instantaneously moves a sufficient stroke in the axial direction to open the valve seat, and supplies a large amount of fluid from the fluid inlet to the fluid outlet via the valve seat. Also, the opening direction axial force acting on the valve shaft from the spring is weakened by the reverse displacement, and the resultant force of the spring force and the maximum static friction force acting on the seal member is caused by the fluid pressure acting on the cross-sectional area of the valve shaft. When the axial force in the closing direction exceeds, the poppet valve element instantaneously moves in the closing direction to close the valve seat, and the supply of fluid from the fluid outlet is instantly stopped.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the embodiments shown in FIGS.

FIG. 1 shows a valve device according to the present invention.
A fluid inlet 12 and a fluid outlet 13 are formed in 11, and a valve seat 14 is formed between the fluid inlet 12 and the fluid outlet 13.

The poppet valve body 15 has a mounting bracket 15b integrally formed with an annular seating portion 15a on the small diameter valve shaft 21.
Are fixed and integrally fixed by cap nuts 15d via washers 15c.

The small-diameter valve shaft 21 extends to the opposite side from the poppet valve body 15 through the opening of the valve seat 14 and is movable with the poppet valve body 15 in the axial direction. A large-diameter valve shaft 22 is integrated with the small-diameter valve shaft 21 by screwing. This large-diameter valve shaft 22 has a sleeve 24 fitted in a center hole 23 of the valve body 11.
Is slidably fitted in the inside of the. This sleeve 24
The valve body by the packing 28 and the stop ring 29
11 and integrated.

A groove 25 is provided on the outer peripheral surface of the large-diameter valve shaft 22, and an O-ring 26 as a seal member is fitted in the groove 25. The O-ring 26 has an original sealing function of preventing air leakage in a sliding gap between the sleeve 24, which is a member on the valve body side, and the large-diameter valve shaft 22, and is more tightly fitted into the sleeve 24 than usual. Therefore, the friction between the O-ring 26 and the sleeve 24 also has an important function of imparting a resistance when the valve shaft 22 moves in the axial direction.

The O-ring 26 has a static friction force due to a large static friction coefficient generated when the valve shaft 22 is at rest,
There are two types of dynamic frictional force, which is generated by the small dynamic friction coefficient generated in the moving state of FIG.

Two large-diameter compression coil springs 31 abut against the shaft end of the large-diameter valve shaft 22, and plungers 32 opposed to each other with the spring 31 interposed therebetween are slidably fitted to the sleeve 24. I have. The coil spring 31 compressed by the plunger 32 acts on the large-diameter valve shaft 22 with the axial force accumulated due to external displacement.

A bracket 35 is fixed to the lower surface of the valve body 11 by screws 34, and an L-shaped plunger operation plate 37 is rotatably provided by the bracket 35 via a shaft 36.
The float shaft 38 is provided integrally with the plunger operation plate 37. One end 37a of the plunger operation plate 37 is bent upward, and when the float shaft 38 rotates downward, the screw 34
Engages with the locking portion 34a provided on one of the heads to prevent the plunger 32 from dropping off.

As shown in FIG. 2, a valve device V according to the present invention comprises a pneumatic source 41 and a pneumatically driven pump (hereinafter referred to as an air pump).
The float 44 attached to the tip of the float shaft 38 is floated on the liquid surface L of the liquid into which the suction pipe 43 of the air pump 42 is inserted, and supplied from the liquid supply pipe 45. When the liquid level L of the liquid to be discharged rises to a certain liquid level, the air pump 42 is driven to control the liquid to be pumped to the discharge pipe 46. The liquid level control system shown in FIG. 2 will be described later in detail.

Next, the operation of this valve device alone will be described with reference to FIG.

First, when the float shaft 38 is rotating downward as shown by the solid line, the poppet is supplied by the fluid inlet 12 and acts on the surface of the poppet valve body 15 by the axial force in the closing direction due to pneumatic pressure. The valve element 15 closes the valve seat 14.

The axial force in the closing direction due to the air pressure acting on the poppet valve element 15 is defined as the axial pressure receiving area defined by the cross-sectional area of the circle in which the poppet valve element 15 comes into contact with the valve seat 14. This is the axial force calculated as the product of pressure and pressure.

Further, as the float shaft 38 rotates upward, the opening axial force acting on the valve shaft 22 from the spring 31 compressed and accumulated via the plunger 32 gradually increases. The static frictional force (downward) acting between the valve shaft 22 and the sleeve 24 gradually increases, so that the valve shaft 22 does not move immediately.

The force accumulated in the spring 31 is
The axial force in the closing direction due to pneumatic force acting on the poppet valve body 15 and O
When the poppet valve element 15 and the valve shaft 22 start moving beyond the resultant force with the maximum static friction force (downward) acting on the ring 26, the axial friction force acting on the O-ring 26 at that moment becomes the maximum static friction. Since the force rapidly decreases from the force to a small kinetic friction force, the poppet valve body 15 and the valve shaft 22 instantaneously move a sufficient stroke upward in the axial direction to open the valve seat 14, and the valve seat 14 is opened from the fluid inlet 12. A large flow of air is supplied to the fluid outlet 13 via the outlet.

The stop position of the poppet valve body 15, which is moved upward to open the valve seat 14, is defined by the cross-sectional area of the large-diameter valve shaft 22 as the axial pressure receiving area and the closing direction determined by the product of this and the air pressure. The spring 31 in which the resultant force of the axial force and the kinetic friction force acting on the O-ring 26 is reduced by the expansion between the plunger 32 and the valve shaft 22
Is determined in a place that balances with the accumulated pressure.

After the raised poppet valve element 15 stops once, the spring 31 acts on the valve shaft 22 against the closing direction axial force determined by the product of the cross-sectional area of the valve shaft 22 and the air pressure. Since the axial force in the opening direction and the static friction force (upward) acting on the O-ring 26 act, the open state of the valve seat 14 is maintained.

Finally, the downward rotation of the float shaft 38 weakens the opening axial force acting on the valve shaft 22 from the spring 31, and the accumulated pressure of the spring 31 and the maximum static friction force acting on the O-ring 26. When the axial force in the closing direction determined by the product of the cross-sectional area of the valve shaft 22 and the air pressure exceeds the resultant force of (upward), the poppet valve element 15 instantaneously moves axially downward in the instant, and the valve seat 14 is closed, and the supply of air from the fluid outlet 13 is stopped.

Next, the operation of the liquid level control system using this valve device will be described with reference to FIG.

As shown in FIG. 2A, when the liquid level L rises due to the supply of the liquid from the liquid supply pipe 45, the plunger 32 is gradually pushed up by the buoyancy of the float 44 of the liquid level L, and the spring 31 is compressed. The cross-sectional area in the circle where the poppet valve element 15 contacts the valve seat 14 is defined as the axial pressure receiving area, and the axial force in the closing direction is determined by the product of the axial pressure receiving area and the air pressure. When the compression force of the spring 31 that has been gradually accumulated exceeds the resultant force with the maximum static friction force (downward), the poppet valve element 15 opens at once and supplies a large amount of air to the air pump 42 at that instant. The liquid is pumped out by an air pump 42 that operates using the supplied air as a driving source.

As shown in FIG. 2B, when the amount of liquid pumped by the air pump 42 is larger than the amount of liquid supplied from the liquid supply pipe 45, the float 44 descends together with the liquid level L, and the spring 31
Compression force is weakening. The axial force in the closing direction, which is determined by the product of the cross-sectional area of the large-diameter valve shaft 22 and the air pressure applied to this cross-sectional area, is the compression force of the spring 31 and the maximum static friction force acting on the O-ring 26 (upward). When the resultant force relatively exceeds the resultant force, the poppet valve element 15 moves downward at that moment, immediately closes the valve seat 14, and stops the air supply to the pump 42.

By stopping the pump and supplying the liquid from the liquid supply pipe 45, the liquid level L recovers to the state shown in FIG.
Hereinafter, the same automatic control of pumping and stopping the liquid between the two levels is performed in the same manner.

[0028]

According to the present invention, the axial force in the opening direction acting on the valve shaft from the spring, the axial force in the closing direction due to the fluid pressure acting on the valve shaft, and the direction opposite to the sealing member when the valve shaft is about to move. Utilizing the static friction force acting on the valve shaft, the valve shaft is made to perform a quick action in the opening direction or the closing direction, so that only one valve device instantaneously supplies or stops a large flow of fluid, The air pump and the like can be operated directly, and the instantaneous opening / closing type can reliably switch the air pump and the like, thereby solving the problem of poor switching.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing one embodiment of a valve device for large flow rate control according to the present invention.

FIG. 2 is an explanatory view showing an example of use of the valve device.

FIG. 3 is a circuit diagram showing a conventional large flow rate control circuit.

[Explanation of symbols]

 11 Valve body 12 Fluid inlet 13 Fluid outlet 14 Valve seat 15 Poppet valve 21, 22 Valve shaft 26 Seal member 31 Spring

Claims (1)

(57) [Claims] 1. A valve device in which a poppet valve body is provided so as to be able to freely contact and separate from a valve seat formed on a valve body between a fluid inlet and a fluid outlet on a fluid inlet side. An axially movable valve shaft extending from the poppet valve body to the opposite side via the valve seat, and a valve shaft fitted to the peripheral surface of the valve shaft by friction with a member on the valve body side. A valve comprising: a seal member that applies a resistance to axial movement; and a spring that is in contact with the shaft end of the valve shaft and applies an axial force accumulated by an external displacement to the valve shaft. apparatus.