JPH04145276A - Valve driving part - Google Patents

Abstract

PURPOSE:To secure such a valve driving part as large in valve-close holding power as compared with a size of the valve driving part by forming a piston with a ferromagnetic material, and setting up a magnet, being opposed to the piston reaching the limit of reciprocation and exerting its suction force on it, in a body. CONSTITUTION:A magnet 50 is attached to an inner bottom surface of a cylinder 32 with a bolt 55, and a piston 40 is formed with a ferromagnetic material. When pressure air is taken into a gateway 43 installed on the inner bottom surface of the cylinder 32, the piston 40 is pushed upward together with a valve stem 15, whereby a diaphragm 20 separates from a valve seat 12, so that a passage 11 is opened and a valve is opened. When the pressure air is discharged, a compression spring 45 depresses the piston 40 together with the valve stem 15, and the diaphragm 20 sticks close to the valve seat 12, thus the valve is closed. At time of valve opening 0% when the valve is fully closed, elastic resilient force of the compression spring becomes reduced, but magnet suction force being exerted on the piston 40 of the magnet 50 is suddenly increased in proportion as the piston 40 approaches the magnet 50, thus a valve driving part thrust depressing the piston 40 composed with these elements, namely, valve-close holding power is reinforced.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a drive unit that opens and closes a valve.More specifically, the present invention relates to a drive unit that opens and closes a valve. This invention relates to an improvement in a valve drive unit that opens or closes a valve by applying a working fluid pressure to a piston that resists elastic repulsive force.

[Prior Art] A valve drive unit that holds a valve in a fully closed or fully open state using the elastic repulsive force of a compression spring via a piston and opens or closes the valve using working fluid pressure is well-known. A valve drive unit that moves the shaft up and down is disclosed in Japanese Patent Publication No. 61-60314, and a valve drive unit that rotates the valve shaft is disclosed in Japanese Patent Application Laid-Open No. 83-266287. This known valve drive unit includes a main body including a cylinder, a piston housed within the cylinder so as to be able to reciprocate in the axial direction, and a working fluid pressure circuit for moving fluid into and out of the cylinder.
For valves that have a compression spring placed between the main body and the piston, and whose valve shaft moves up and down to open and close, the valve shaft is directly connected to the piston, and for valves whose valve shaft rotates to open and close, there is a straight line between the piston and the valve shaft. A transmission mechanism is provided to convert the motion into rotational motion, such that when working fluid pressure is introduced into the cylinder, the piston slides to open or close the valve, and when working fluid pressure is removed from the cylinder, a compression spring moves the piston back. Close or open the valve.

For example, when opening a valve using air pressure, pressurized air is introduced into one side of the piston, the piston slides to the other side, and the valve stem moves straight or rotates in one direction to open the valve. A compression spring is compressed and its elastic repulsive force becomes stronger. When this pressurized air is released, the piston is pushed back by the elastic repulsive force of the compression spring, and the valve shaft slides or rotates in the opposite direction to close the valve. When the valve closes, the compression spring stretches and its elastic repulsive force is minimized, but this minimum elastic repulsive force must be used to keep the valve closed against the pressure of the fluid inside the valve that tries to open the valve. On the other hand, when closing a valve with air pressure, the compression spring compresses to its maximum elastic repulsion force when the valve closes, so in order to keep the valve closed, its maximum bony repulsion force must be A high air pressure is required to overcome the sum of the pressure of the fluid in the valve and the pressure of the fluid in the valve.

[Problem to be solved by the invention] When the fluid working pressure of the valve is increased, the force with which the fluid tries to open the valve when it is fully closed increases, so the force to keep the valve closed must also be increased. Increasing the elastic repulsion force of the compression spring or the working fluid pressure of the valve drive part becomes correspondingly larger and more robust. This large, sturdy valve drive is expensive and creates space constraints. Furthermore, this runs counter to the desire for valve miniaturization.

The present invention has been made to solve these problems, and its purpose is to provide a valve drive section that has a larger valve closing force than conventional valve drive sections compared to the size of the valve drive section. be.

[Means for Solving the Problems] In order to achieve the above object, the means adopted by the present invention includes a main body including a cylinder, a piston inserted into the cylinder so as to be able to reciprocate, and a transmission mechanism directly connected to the piston or a transmission mechanism. A valve drive unit including a valve shaft connected via a valve shaft, a compression spring disposed between the main body and the piston, and a working fluid pressure circuit that reciprocates the piston against the compression spring,
The piston is made of a ferromagnetic material, and a magnet is placed in the main body to face the piston and apply an attractive force to it when it reaches the limit of its reciprocating motion.

The magnet may be a permanent magnet or an electromagnet whose excitation can be controlled. In order to concentrate the lines of magnetic force of the magnet on the piston, it is desirable that components other than the piston be made of non-magnetic or weakly magnetic materials.

[Operation] When working fluid pressure such as air pressure is introduced into the cylinder, the piston moves from one limit to the other limit against the compression spring to fully open or close the valve, and when the air pressure is discharged, The piston returns from the other limit to one limit due to the elastic repulsive force of the compression spring, fully closing or opening the valve.
In the valve drive unit of the present invention, when the piston moves to the other limit, the magnet provided in the main body exerts a magnetic attraction force on the ferromagnetic piston in the direction in which the valve closes.In this way, the valve is driven by the working fluid pressure. When opening the valve, the elastic repulsive force of the compression spring plus the magnetic attraction force is the force that keeps the valve closed; when the valve is closed by working fluid pressure, the thrust force of the working fluid pressure plus the magnetic attraction force is the force that keeps the valve closed. Therefore, the valve-closing holding force is significantly increased compared to conventional compression springs that depend only on the minimum elastic repulsion force or the working fluid pressure. Therefore, if the size of the compression spring or the working fluid pressure is the same as that of the conventional one, that is, if the size of the valve drive part is the same as that of the conventional one,
The available fluid pressure is higher, and for the same fluid pressure, a smaller compression spring or actuating fluid pressure can be used, ie the valve drive can be made more compact.

[Example] The valve drive unit of the present invention will be specifically described based on an example shown in the drawings.

The first embodiment shown in FIGS. 1 and 2 is a diaphragm valve that opens with air and closes with a compression spring. The valve includes a valve body 10 that includes a flow path 11 and a valve seat 12 that divides the flow path into two;
A diaphragm 20 that covers the upper opening of the valve seat 12, a bonnet 31 that tightly fixes the periphery of the diaphragm to the valve body lO, and a valve shaft 15 whose lower end is locked to the center of the upper surface of the diaphragm 20 via the compressor 16. , a cylinder 32 connected and fixed to the upper surface of the bonnet 31, a cap 33 connected and fixed to the upper surface of the cylinder, a piston 40 fitted to the valve shaft 15 via the stem rod 13, and the piston. It includes an O-ring 41 provided on the outer peripheral surface and a compression spring 45 disposed between the upper surface of the piston 40 and the inner upper surface of the cap 33. bonnet 3
1, the cylinder 32, and the cap 33 are the main body 30 of the valve drive unit.
form. The configuration up to this point is the same as the conventional one, but unlike the conventional one, there is a magnet 50 on the inner bottom surface of the cylinder 32.
is attached by Porto 55. The magnet 50 may be a permanent magnet or an electromagnet whose excitation can be controlled, but the piston 4
0 must be a ferromagnetic material. The material of the cylinder 32 and valve stem 15 near the magnet 50 and the piston 40 is a non-magnetic material such as aluminum or stainless steel, or a weak magnetic material.

A pressure air inlet/outlet 43 is provided on the inner bottom surface of the cylinder 32, and as shown in FIG. The flow path 11 is open and the valve is open. As shown in Fig. 3, when the valve opening is 100%, the compression spring is compressed and the elastic repulsive force is the maximum of 100 kg, for example.
It becomes f. When the pressurized air is discharged, as shown in FIG. 1, the compression spring 45 pushes down the piston 40 together with the valve shaft 15, and the diaphragm 20 comes into close contact with the valve seat 12, so that the valve is closed. As shown in Figure 3, when the valve is fully closed and the valve opening is 0%, the elastic repulsive force of the compression spring is a minimum of 50 Kgf, but the magnetic attraction force exerted on the magnet piston increases rapidly as the piston approaches the magnet. Therefore, the thrust force of the valve drive unit that pushes down the piston, that is, the force that holds the valve closed, is 100 Kgf, which is the same as the maximum elastic repulsion force of the compression spring.

In the first embodiment reinforced with the magnet 50, the size of the valve drive unit main body 30 is the same, but the valve closing force is twice as large as that of the conventional one using only a compression spring. The working pressure can also be doubled.

The second embodiment shown in FIG. 4 is a diaphragm valve that opens the valve using a compression spring and closes the valve using air pressure.

In this second embodiment, a compression spring 45 is provided below the piston 40. The cap 33 is sealed, and pressurized air is introduced into its interior through an inlet/outlet 43. The structure other than these is the same as that of the first embodiment, and the magnet 50 is fixed to the cylinder 32 by a port 55. When the valve is closed by introducing pressurized air, the compression spring 45 has the maximum elastic repulsion force, and tries to push up the valve stem 15 with the thrust force that is the sum of the elastic repulsion force and the pressure of the fluid in the valve. Since the attractive force between the piston 40 and the magnet 50 reduces the thrust, the air pressure required to keep the valve closed can be reduced compared to the conventional case. Therefore, if the operating air pressure is the same as before, that is,
If the size of the valve drive unit main body 30 is the same, it is possible to increase the fluid working pressure compared to the conventional one, and if the fluid working pressure is the same as before, it is possible to lower the operating air pressure, that is, to increase the valve drive unit main body 30. It can be made smaller.

As shown in the third embodiment of FIG. 5, magnets 50 and 51 may be attached to both the cylinder 32 and the cap 33 of the main body 30 through ports 55 and 56, respectively. The reinforcing action is exactly the same as the second embodiment shown in FIG. The magnet 51 is the piston 40 that approaches when fully opened.
By applying a magnetic attraction force to the valve shaft 15 and raising the valve stem 15, the force for holding the valve closed is reinforced.

The fourth embodiment shown in FIGS. 6 and 7 is a valve drive unit used in a pole valve, a pull-toughfly valve, etc., which opens and closes the valve by rotating the valve shaft by 90 degrees. In the valve drive section, a drive shaft 18 directly connected to the valve shaft is supported in the center of the main body 30, and a cam 22 is fixed to the drive shaft. A cam pin 24 is inserted into the cam groove 23 of the cam 22, and the cam pin is pivotally attached to a slider 25 that reciprocates within the cylinder 32. The slider 25 is also fixed to a piston 40 that is reciprocably inserted into the cylinder 32, and left and right caps 3 are provided on both sides of the cylinder 32.
3 is fixed. A compression spring 45 is disposed between the outer surface of the piston 40 and the inner surface of the cap 33, and a pressurized air outlet (not shown) is provided in the center of the cylinder 32. When pressurized air is introduced into the cylinder 32, the piston 40 moves to the left and right limits together with the slider 25, and the cam pin 24 integrated with the slider rotates the cam 22 90 degrees through the cam groove 23 to open the valve. When the air is released, the piston 40 moves to its inner limit due to the elastic repulsive force of the left and right compression springs 45, and the cam 22 is reversed by 90 degrees to close the valve.

The configuration so far is the same as the conventional one, but unlike the conventional one, the left and right pistons 40 are made of ferromagnetic material,
A bottomed sleeve 48 also made of ferromagnetic material is coaxially fixed to its outer surface. A rod 34 passing through the bottom of the sleeve 48 is fixed to the cap 33. A magnet 50 is attached to the inner end of the rod 34, which contacts the inner bottom surface of the sleeve 48 when the piston 40 is in the inner limit position and the outer surface of the piston 40 when the piston 40 is in the outer limit position. Also, a magnet 51 is attached to the inner bottom surface of the cap 33, which faces the outer bottom surface of the sleeve 48 when the piston 40 reaches its outer limit.

When the valve closes, the compression spring 45 stretches and the elastic repulsive force is minimal, but this is reinforced by the attractive force between the magnet 50 and the inner bottom surface of the sleeve 48, so the valve closing force is greater than that of the conventional stretched force. This is much larger than when relying only on the minimum elastic repulsion force of the compression spring. Therefore, the fluid working pressure can be increased accordingly. Conversely, if the fluid working pressure is the same, the valve drive unit can be made smaller than before. When the valve is opened, the maximum elastic repulsive force of the compression spring acts in the direction of closing the valve, weakening the force that holds the valve open, but the piston 4
0 and the magnet 50 at the tip of the rod 34, as well as the magnetic attraction force between the magnet 51 on the inner bottom surface of the cap 33 and the outer bottom surface of the sleeve 48, reinforcing the valve opening holding force.
It is also possible to reduce the pressure of pressurized air required to maintain the valve open.

[Effects of the Invention] As described above, in the valve drive unit of the present invention, a magnet is attached to the main body, and when the valve is closed, the magnet exerts a magnetic attraction force on the ferromagnetic piston in the direction in which the valve closes, thereby causing the compression spring or Since the force to keep the valve closed is reinforced by the working fluid pressure, the force to keep the valve closed is significantly stronger, unlike conventional systems that rely only on compression springs or working fluid pressure. Therefore, the valve drive section of the present invention is
If the size is the same as the conventional one, it is possible to increase the fluid working pressure, and if the fluid working pressure is the same, it is possible to make the valve drive part smaller. be effective.

Furthermore, the structure in which the main body is provided with magnets that apply magnetic attraction force to the piston at both limits of the piston reciprocating motion has the effect of reinforcing not only the force of the valve driving section to keep the valve closed but also the force to keep the valve open.

[Brief explanation of drawings]

1 and 2 are cross-sectional views showing the closed and opened states of a diaphragm valve equipped with a first embodiment of the valve drive unit of the present invention, respectively, and FIG. 3 is a valve shaft of the first embodiment. A graph showing the thrust force acting on. Figures 4 and 5 are views corresponding to Figures 1 and 2 of the second and third embodiments, Figures 6 and 7 are valves of the valve drive unit of the fourth embodiment in which the valve shaft rotates. FIG. 3 is a half-sectional view showing the valve when it is closed and when it is open. In the figure, numeral 15 is a valve stem, 20 is a diaphragm, 2
2 is a cam, 23 is a cam groove, 24 is a cam pin, 25 is a slider, 30 is a main body, 31 is a bonnet, 32 is a cylinder, 33 is a cap, 34 is a rod, 40 is a piston, 4
5 is a compression spring, 48 is a sleeve, and 50.51 is a magnet, respectively. Applicant Nippon Dia Valve Co., Ltd. Procedural Amendment April 1991

Claims (1)

[Scope of Claims] 1) a main body (30) including a cylinder (32), a piston (40) inserted into the cylinder so as to be able to reciprocate and slide;
A valve shaft (15) connected to the piston directly or via a transmission mechanism, a compression spring (45) provided between the piston and the main body, and a compression spring (45) for sliding the piston against the compression spring. The piston is formed from a ferromagnetic material, and the piston is formed of a ferromagnetic material,
A valve drive unit characterized in that the main body is provided with a magnet (50) that applies an attractive force to the piston when it reaches the limit of reciprocating motion, at least in the direction in which the valve closes. 2) The main body (30) has magnets (50, 51) each exerting an attractive force on the piston (40) that has reached both limits of reciprocating motion.
2. The valve drive unit according to claim 1, wherein the valve drive unit is provided in the valve drive unit.