JPH0260916B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cap nut tightening fluid coupling which has an unprecedentedly high degree of airtightness and also prevents the generation of particles.

In recent years, with the increasing speed of technological innovation, super LSI
As seen in ultra-super LSIs, there is a growing need to manufacture dramatically large-scale integrated circuits.
In order to manufacture such large-scale integrated circuits, it is necessary to use super-toxic gaseous fluids such as the companion conductor compound gallium arsenide and to form highly pure films under ultra-high vacuum. Semiconductor manufacturing equipment is inevitably required to have a high degree of airtightness.

However, in order to connect the flow path forming elements of such a device, it is impossible to weld all of them, and the device cannot be completed without a fluid coupling that is mechanically connected and has excellent airtightness. I can't do that. The fittings used for this purpose are mainly made in foreign countries because of their high reliability, and there are various types.
A typical example is the one shown in Figure 3.
Two sleeves 1 and 2 are connected via a gasket 3, and a nut 5 fitted into the other sleeve 2 is connected to a gland 4 having a threaded portion formed on the outer periphery of the sleeve 1. An example of this is a fluid coupling that is achieved by screwing together the two. On the other hand, as shown in FIG. 2, the gasket is constructed by holding a coil spring 19 formed into a circle by connecting both ends of a relatively thin helical coil spring with a metal tube 20 so that the outer center is open. Many things have been developed. Since this gasket has advantages such as being able to be used under low tightening force, the inventor of the present invention came up with the idea of using this gasket in the above-mentioned joint, and obtained very good results. However, when the lever gasket is tightened, the repulsive force of the coil spring damages the surface (sealing surface) where the metal tube of the gasket contacts the body and sleeve through the gasket, resulting in a high degree of airtightness. In addition, there was a problem in that fine linear scratches were formed on the gasket, making it impossible to use the expensive gasket repeatedly. In addition, since the sealing surface has minute irregularities, there is a risk that the particles contained in these irregularities may get mixed into the reaction gas. A fatal drawback for a semiconductor manufacturing joint was that it could be carried onto the wafer and damage the wafer.

"Means for Solving the Problems" The inventor has proposed that on the contact surface between the body and the sleeve,
A fitting recess and a fitting protrusion are respectively provided so that the end face of the fitting recess comes into contact with the step of the fitting protrusion so that the gasket is not compressed beyond the effective elastic compression amount, and the gasket between the body and the sleeve is By forming a roll burnishing surface on the surface that comes into contact with the gasket, and using a gasket made of a ring-shaped coil spring held by a metal tube with a C-shaped cross section as the gasket, the sealing surface and gasket are free from scratches. The present invention has been achieved based on the discovery that it is possible to prevent particles from forming and, as a result, maintain a high degree of airtightness and also prevent particles from being mixed into the reaction gas.

Although roll burnishing itself is a well-known method, conventionally it has not been known at all to perform roll burnishing on the surfaces of the body and sleeve that come into contact with each other through a gasket. Currently, there is no known or commercially available machine that can perform roll burnishing on such surfaces. That is, with the conventional gasket, there is no possibility that scratches would be formed on the surfaces of the body and sleeve that abut through the gasket due to the repulsive force of the spring.

The effects of the present invention are due to the fact that the stepped portion provided on the contact surface between the body and the gasket prevents the gasket from being damaged due to over-tightening;
This is thought to be because roll burnishing improves surface hardness, which makes the treated surface and gasket less likely to be scratched, and as a result, a high degree of airtightness can be maintained. Further, since the surface becomes smooth by roll burnishing, the risk of particles contained in minute irregularities being mixed into the reaction gas when roll burnishing is not performed is also eliminated.

"Example" Next, an example of the present invention will be described based on the drawings.

In FIG. 1, 11 is a body, 12 is a sleeve, and 13 is a cap nut, and the cap nut 13 is fitted into the sleeve 12.

An annular recess 21 is provided on the end surface of the body 11 on the screw 14 side, and a protrusion 2 that fits into the recess 21 is provided on the surface of the sleeve 12 that contacts the gasket 15.
2 are provided. The gasket 15 is fitted into the recess 21 and pressed against the protrusion 22. The depth of the concave portion 21 and the height of the convex portion 22 are set so that the stepped portion 23 of the convex portion 22 rests on the end surface 24 of the body when the gasket is pressed to an effective elastic compression amount.

Gasket 15 between body 11 and sleeve 12
The surface in contact with the roll burnishing surface 3
0,31 are formed.

Roll burnishing process involves rotating rotating rollers.
This can be done by applying the contact surfaces of the gaskets of the body and sleeve, respectively. For example, if the sealing surface of the fluid coupling in the above embodiment is turned with a roughness of 3.2S and subjected to roll burnishing, 1~
A mirror surface with a roughness of 0.8S can be easily obtained in 2 seconds of machining time. This burnishing treatment improves the surface hardness (in the case of stainless steel, the base material hardness is 180HB, but the hardness becomes over 300HB), which makes it difficult for scratches to form on the sealing surface and creates a smooth surface. Therefore, the generation of particles is also prevented.

The gasket 15 used in the above embodiment is
As shown in the figure, a coil spring 19 is formed by connecting both ends of a relatively thin helical coil spring into a circular shape.
is held by a metal tube 20 so that the center of the outside is open. The material of the coil spring 18 is, for example, stainless steel or Inconel, and the material of the metal tube 20 is aluminum, nickel, nickel, etc.
Copper, Monel, etc. are preferably used.

``Effects'' As described above, the fluid coupling of the present invention uses a special gasket, which prevents over-tightening, and roll burnishing the sealing surface, which prevents scratches from forming on the sealing surface. As a result, a high degree of airtightness is obtained, and minute linear scratches are less likely to be formed on the gasket, so a high degree of airtightness can be obtained with low tightening force, and the gasket can be used repeatedly many times. can.
Therefore, the fluid coupling of the present invention has excellent airtightness, and even non-experts can handle helium leak crates.
It is possible to easily obtain a fluid joint with an extremely high degree of airtightness of 10 ^-10 atm/cc/sec, which has never existed before. Further, by applying the roll burnishing treatment to the abutting surface of the gasket, the surface becomes smooth, thereby eliminating the risk of particles resulting from the unevenness of the sealing surface being mixed into the reaction gas.

[Brief explanation of drawings]

FIG. 1 is a half-sectional view showing an embodiment of the present invention, FIG. 2 is a partially cutaway perspective view of a gasket of the present invention,
FIG. 3 is a sectional view showing a conventional fluid coupling. In the figure, 15... gasket, 19... ring-shaped coil spring, 20... metal tube.

Claims (1)

[Claims] 1 A body provided with a threaded portion on the outer periphery of one end of the tube,
A sleeve made of a tube having a short annular portion on the outer periphery of the tip that contacts and communicates with a through hole on the threaded portion side of the body via a gasket, and a sleeve that is fitted into the sleeve and screwed into the threaded portion of the body. In a fluid coupling comprising a cap nut that firmly tightens the body and the sleeve, a fitting recess and a fitting protrusion are provided on the contact surfaces of the body and the sleeve, respectively, and a fitting convex portion is provided on the contact surface of the body and the sleeve. The gasket is provided so that the end surface abuts against the stepped portion of the fitting convex portion and the gasket is not compressed beyond the effective elastic compression amount, and a roll burnishing surface is formed on the surface of the body and the sleeve that abut through the gasket. A highly airtight cap nut tightening fluid coupling for semiconductor manufacturing equipment, characterized by using a gasket formed by holding a ring-shaped coil spring in a metal tube having a C-shaped cross section.