JPH05149464A - Control valve - Google Patents

Abstract

PURPOSE:To produce great force with a magnetic gap made small, and execute great flow rate control stably by sealing the magnetic gap which determines the stroke of a plunger for driving a valve body, and concurrently specular finishing opposing surfaces forming the magnetic gap. CONSTITUTION:Plural flow paths 2 and 3 are formed in a base 1, diaphragms 5 are laminated over an upper surface via a spacer 4, and a valve body 7 is housed in the inside of the diaphragms. A chassis 15 which houses a mechanism driving a plunger 14 by means of an electromagnetic method, is disposed on the upper section of the diaphragms 5, and the bearing section 17 of a shaft 16 combined with the plunger 14 is formed for the chassis. Furthermore, the coil case 18 of a coil 19 is housed in the inside of the chassis 15, and a cover body 20 is concurrently pressed in the upper section. A magnetic gap regulating disc 23 is threadedly engaged with a screw 22 formed at the upper section of the shaft 16, and the upper section of the cover body 20 and the bottom surface of the disc 23 are concurrently finished to a mirror surface respectively. Meanwhile, respective 'O' rings 21 and 24 are interposed in spaces among the chassis 15, the shaft 16 and the disc 23.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control valve of a type driven by a solenoid actuator used in a semiconductor manufacturing process or the like.

[0002]

2. Description of the Related Art As a conventional control valve of this type, an actual open valve 59 is used.
A solenoid valve disclosed in Japanese Patent Publication No. 77676 is known.
This solenoid valve has the advantages that the displacement value of the plunger can be designed relatively freely, the flow rate can be controlled up to a large flow rate of about 20 SLM or more, and it is cheaper than other types of control valves. .. However, according to the control valve of this configuration, particularly when gas is used as the fluid, the fluid enters into the accommodation portion of the plunger through the slight gap between the plunger and the inner peripheral surface of the plunger pipe, and remains there. To do. Therefore, when the fluid (gas) is switched, there is a problem that the remaining fluid and the new fluid are mixed. Such a problem is particularly serious in a semiconductor manufacturing process in which several gases are switched and given to the same semiconductor. Therefore, there is a demand for a structure in which the inner surface area of the portion where the fluid enters is small and retention is unlikely to occur. When the fluid is gas, it is desirable that it can be easily removed by a gas purge or the like.

On the other hand, as disclosed in Japanese Utility Model Laid-Open No. 2-76859, a control valve using a piezoelectric element having a structure in which a residual portion of gas is eliminated by using a diaphragm is also known.
In the control valve of this structure, the diaphragm receives the internal pressure due to the fluid (gas), and the force F due to this internal pressure is F = S · V when the effective area of the diaphragm is Scm ² and the internal pressure is Vkg / cm ^2. For example, when V = 2 kg / cm ² and S = 4 cm ² , F = 8 kg, and the force of the piezoelectric element is usually 10 kg.
From the above, control is sufficiently possible.

[0004]

However, the above-mentioned conventional control valve using a piezoelectric element inherits the problems of the piezoelectric element. That is, the stroke of the piezoelectric element is generally as small as a few microns at 150 VDC and is not suitable for large flow rate control. Further, the control voltage is high, a special DC booster circuit is required, and it is hard to say that it is excellent from the viewpoint of safety. Further, the piezoelectric element is made by laminating a large number of thin (about 0.2 mm) ceramic plates, which is structurally fragile and expensive.

The present invention has been made in order to solve the problems of the conventional control valve as described above, and its purpose is to enable large flow rate control and to drive the valve with sufficient force. To provide a control valve.

[0006]

The control valve according to the present invention comprises:
A solenoid actuator having a valve body for opening and closing the valve port, a plunger for driving the valve body, a shut-off means for preventing the control fluid from flowing into the plunger of the solenoid actuator, and the plunger. Of the magnetic gap portion and a seal member for sealing the magnetic gap portion from the outside, and the opposing surfaces constituting the magnetic gap portion are mirror-finished. To do. Further, in the control valve according to the present invention, a control fluid flows into a solenoid actuator having a valve body that opens and closes a valve opening, a plunger that drives the valve body, and a plunger of the solenoid actuator. And a shut-off means for blocking the valve body, the shut-off means being composed of a metal bellows having a diameter smaller than the effective radius of the valve body.

[0007]

Since the control valve according to the present invention is constructed as described above, the magnetic gap portion can be made extremely small,
It is possible to generate a sufficiently large force. Further, the magnetic gap portion is sealed by the blocking means so that no dust enters and the mirror-finished portion of the magnetic gap portion can be kept dust-free forever.

Further, by using the metal bellows as the shut-off means, the pressure of the control fluid is received only by the bellows portion, and there is an advantage that the valve driving force can be easily obtained.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A control valve according to the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a control valve according to an embodiment of the present invention. FIG. 2 shows a plan view of the control valve.

The control valve is erected on a base 1 in which a fluid comes from a fluid source and a flow path toward a supply destination is formed. The base 1 is formed with flow passages 2 and 3 as well as screw holes for fixing the control valve. A diaphragm 5 is laminated via a spacer 4 in alignment with the screw hole portion, and a nut 6 is laminated on the diaphragm 5 in alignment with the screw hole. The outer peripheral edges of the spacer 4, the diaphragm 5 and the nut 6 are all substantially square and chamfered at their four corners, as can be seen from FIG. The inner peripheral edge of the spacer 4 has a circular shape, and the inner chamber of the diaphragm 5 is tapered from the inner peripheral edge of the spacer 4 to a taper shape from a portion slightly larger than the outer periphery of the valve body 7. The depth is increased to a height slightly higher than the height of the valve body 7. The valve body 7 is formed on a substantially disc, and a concave portion for accommodating the spring 8 is formed on the bottom surface thereof, and a convex portion for contacting the diaphragm 5 is formed on the upper portion. Spacer 4, diaphragm 5,
The nuts 6 are screwed into holes corresponding to the screw holes of the base 1 respectively formed, and are fixed to the base 1. At this time, for example, a metallic O-ring 13 is provided at a portion adjacent to the inner wall of the spacer 4 and the lower end surface of the diaphragm 5 to prevent fluid leakage.

On the upper portion of the nut 6 is a housing 15 in which a mechanism for driving the plunger 14 by an electromagnetic method is housed.
Is erected. The housing 15 is formed in a cylindrical shape, and a screw 15A is formed on the outer peripheral portion of the cylindrical portion narrowed at the lower end. The portion of the screw 15A is screwed into the screw hole of the container 6 via the span adjusting nut 16. The housing 15 has a receiving portion 1 for a shaft 16 coupled to the plunger 14.
7 is formed at the joint between the plunger 14 and the shaft 16. Reference numeral 18 is a coil case, in which a coil 19 wound in a predetermined direction is housed, and a guide hole 18A for the shaft 16 is formed in the central portion. The inner wall of the upper portion of the casing 15 is formed to be slightly thin, and a substantially disc-shaped lid 20 is press-fitted into the casing 15 in the step portion formed by such thin formation. It is fixed. A hole 20A for passing the shaft 16 is formed in the central portion of the lid body 20, and a rubber O-ring 21, for example, is interposed in a portion of the shaft 16 corresponding to the hole 20A. Axis 16
A screw 22 is formed on the upper end of the. This screw 22
On the other hand, a disk 23 for adjusting the magnetic gap portion, which is disk-shaped and has a screw formed in the central portion, is screwed. An O-ring 24 made of rubber, for example, is interposed between the outer peripheral surface of the disk 23 and the upper inner wall surface of the housing 15. Both the upper portion of the lid 20 and the bottom surface of the disk 23 are mirror-finished, and work to increase the force of the solenoid valve as described later. A screw is formed in the center of the disk 23, and a fixed nut 25 having an inverted cup shape is provided on the shaft 16.
The screw 22 is screwed together.

In the control valve having the above structure, when the casing 15 is erected on the nut 6, the screwing amount of the screw 15A of the casing 15 is set to the screw formed on the nut 6 which is the span adjusting nut. Then, the housing 15 is fixed by the screw formed on the nut 6, and the housing 1 has a desired span.
5 and the nut 6 are connected.

In this way, after the housing 15 is erected on the nut 6, the disk 23 is screwed into the screw 22 at the upper end of the shaft 16, and the magnetic force is adjusted by adjusting the screwing amount. The gap g is set as desired. In this state, the fixing nut 25 is further screwed, and this portion is also accurately fixed by the double nut. The holes 31 to 34 shown in FIG.
Shows the hole into which the jig is inserted when rotating and tightening.

Now, the force F of the actuator due to the solenoid valve will be considered. Assuming that the number of turns of the coil 19 is T, the current flowing through the coil 19 is I, the gap is g, and the facing area of the gap is S, the force F is

[Equation 1] Therefore, the smaller the gap g, the larger the force generated. Therefore, in the above-described embodiment, the lower surface of the disk 23 that forms the gap g and the upper surface of the lid 13 are mirror-finished, and this portion is sealed by the O-rings 21 and 24 so that dust does not enter. Ideally, the gap g can be close to zero, and the required force F (up to 10 kg or more) can be obtained. In the present embodiment, the number of coil turns: 3600T current value: 150 mA (MAX) applied voltage value: 20 V (MAX) plunger diameter: 7 mmφ (coil part), 10 mmφ
(Lower part) 25 mmφ (gap part) Stroke reduction ratio: 3: 1 Stroke before reduction; 0.24 mm (MAX) Stroke after reduction; 80 μm (MAX) Generation force before amplification; 5 Kg (MAX) After amplification Generated force: 15 kg (MAX) Orifice diameter: 20 mmφ Flow rate: 25 SLM (gas N ₂ , differential pressure 1 kg
/ Cm ² ).

That is, when no current is passed through the coil 19 in the control valve, the spring 8 pushes up the valve element 7 to bring about a predetermined fully open state. Coil 19
When a current is applied to the plunger 14, the plunger 14 is pushed down correspondingly, and an opening state slightly closed from the fully open state appears. Thereafter, the opening degree is narrowed according to the value of the current flowing through the coil 19, and finally the closed state is reached. During this time, the plunger 14 is pushed down, so that the valve body 7 is depressed by the spring through the diaphragm 5 and pushed down.

The magnetic fluid 26 is interposed by the magnetic fluid holder 27 on the inner wall surface of the hole for accommodating the plunger 14, the outer peripheral surface of the plunger 14 and a part of the shaft 16 corresponding to the receiving portion 17. Since it is mounted, it stabilizes the magnetic resistance in this portion and acts like a so-called lubricating oil to make the movement of the plunger 14 smooth so that the applied voltage to the coil 19 and the stroke are increased. The curve corresponding to and changes smoothly without zigzag, making it easy to achieve a desired opening. FIG. 3 shows a perspective view of the magnetic flow holder 27. The magnetic flow holder 27 has an annular shape, in which a permanent magnet 27 ₁ is arranged in the middle stage, and magnetic bodies 27 ₂ and 27 ₃ are laminated and fixed on the upper and lower sides.

Further, the fluid enters only the inner chamber of the diaphragm 5 in which the valve body 7 is provided, and there is no special narrow gap or the like in this portion to reduce the retention of the fluid (especially gas). be able to.

Further, as shown in FIG. 4, the valve body 7 has a leg portion 71 protruding downward in an annular shape as shown in FIG. A suitable orifice can be realized by preparing the above and selecting it as necessary.

FIG. 5 shows an embodiment in which a metal bellows is used instead of the diaphragm 5 to reduce the influence of the fluid pressure on the plunger. In the figure, the same components as those in FIG. 1 are designated by the same reference numerals. A chamber 61 capable of accommodating the valve body 7 is formed at the center of the lower surface, and a metal bellows 62 having an inner space corresponding to the head of the valve body 7 is hung from the center of the upper surface to form a bobbin-shaped blocker. 63 is FIG.
Is used instead of the diaphragm 5 to create a control valve. According to this structure, the protrusion 14A protruding downward of the plunger 14 contacts the upper part of the bevel 62, and the tip of the bevel 62 presses the head of the valve body 7. Even if the fluid enters the chamber provided with the valve body 7 at an appropriate pressure,
By reducing the bellows 62, internal pressure is not applied to the entire surface such as the diaphragm. The top plate 64 on the upper portion of the chamber 61 is sufficiently thicker than the central portion of the diaphragm 5. A female screw 65 that is screwed into a male screw formed on the leg portion of the housing 15 is formed on the inner wall of the hole above the blocking body 63.

The magnetic fluid holder is not always necessary in each embodiment.

[0021]

As described above, according to the present invention,
Even if it is a solenoid plunger, the valve can be driven with sufficient force by mirror-finishing the magnetic gap.

Further, the control valve of the present invention is provided with the shut-off means for shutting off the valve drive body from other members on the valve body side, so that the fluid does not enter from the valve body side to the valve drive body side. It is possible to prevent (particularly gas) from remaining (accumulating). Further, the valve is driven by an electromagnetic method, and the stroke is sufficiently taken.

Further, by using the metal bellows as the shut-off means, the influence of the fluid pressure can be reduced, and it is possible to cope with the case where the valve driving power is not sufficient. In addition, since the magnetic fluid is interposed in the magnetic circuit part where the plunger moves, a smooth movement of the plunger is realized, and zigzag does not occur in the characteristic curve of the coil applied voltage and the stroke. Enables suitable fluid control.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention.

FIG. 2 is a plan view of an embodiment of the present invention.

FIG. 3 is a perspective view of an essential part of an embodiment of the present invention.

FIG. 4 is a perspective view of an essential part of another embodiment of the present invention.

FIG. 5 is a sectional view of another embodiment of the present invention.

[Explanation of symbols]

1 ... Base 2, 3 ... Flow path 4 ... Spacer 5 ... Diaphragm 6 ... Nut 7 ... Valve body 8 ... Spring 13 ... O-ring 14 ... Plunger 15 ... Housing 16 ... Shaft 18 ... Coil case
Reference numeral 19 ... Coil 20 ... Lid 21, 24 ... O-ring 23 ... Disk 25 ... Fixing nut 26 ... Magnetic fluid 27 ... Magnetic fluid holder

Claims (3)

[Claims] 1. A solenoid actuator having a valve body for opening and closing a valve opening, a plunger for driving the valve body, and a shutoff means for preventing a control fluid from flowing into the plunger of the solenoid actuator. A magnetic gap portion that determines the stroke of the plunger, and a seal member that seals the magnetic gap portion from the outside, and the facing surface that constitutes the magnetic gap portion is mirror-finished. A control valve body characterized by being present. 2. A valve body for opening and closing a valve opening, a solenoid actuator having a plunger for driving the valve body, and a shutoff means for preventing a control fluid from flowing into the plunger of the solenoid actuator. And a metal bellows having a diameter smaller than the effective radius of the valve body.
A control valve body characterized by comprising 3. A magnetic circuit is provided in a portion where the plunger moves, and a magnetic fluid is interposed in at least a part of the magnetic circuit.
The control valve described.