JP2004044621A - Metal seal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metal seal having low fastening force and large restoration amount, substituting for a conventional rubber-made O-ring. <P>SOLUTION: The metal seal S is inserted between a first flat surface and a second flat surface in parallel each other. The metal seal is provided with a first contact part 11 of projecting cross section, a second contact part 12 of projecting cross section, and an intermediate wall part 13 in diameter-enlarging tapered shape for interconnecting the both contact parts. A curvature radius of the second contact part 12 is larger than that of the first contact part 11. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to metal seals.
[0002]
[Prior art]
Conventionally, rubber O-rings have been widely used as seal materials, but may not be used in high temperature, low temperature, rubber corrosive gas environments, and the like. Therefore, metal seals such as the following (1) to (4) have conventionally been used. That is, (1) metal O-ring, (2) metal C-ring, (3) spring-loaded C-ring, (4) legend seal and the like are used.
[0003]
[Problems to be solved by the invention]
However, each metal seal has the following problems.
{Circle around (1)} Metal O-rings These are the most common and proven metal seals and provide stable sealing performance, but have drawbacks such as a large clamping force and a small restoration amount of about 0.05 mm.
{Circle around (2)} Metal C-ring The tightening force is smaller than the metal O-ring, and the restoration amount is relatively large, about 0.05 mm to 0.15 mm. However, depending on the application (use conditions), the value of the tightening force is still large and the amount of restoration is insufficient.
{Circle around (3)} The spring-loaded C-ring restoration amount is as large as 0.1 to 0.15 mm. However, the restoration amount is insufficient depending on the use (use condition). Furthermore, since the coil spring is inserted into the C-ring body so as to enclose it, there is a drawback that the production is troublesome and the structure is complicated, and the tightening force is large and the cost is high.
{Circle around (4)} Resilient seal The fastening force is smaller than other metal seals, and the restoration amount is as large as 0.1 to 0.2 mm. However, since it is a cutting process, the production is troublesome and very expensive.
[0004]
In short, none of the conventional metal seals can satisfy all the conditions (requests) of being easy to manufacture, having a small fastening force, having a large restoring force, and being inexpensive.
In particular, if the material of the mounting member to which the seal is attached is inappropriate for a brittle material such as ceramics or a soft material such as aluminum, or if the depth dimension tolerance of the seal groove is large, the sealing performance (sealing performance) There is also a problem that the seal tends to vary, a set height range in which the seal can be used is narrow, and attention must be paid to the installation of the seal.
[0005]
[Means for Solving the Problems]
According to the present invention, there is provided a metal seal which is interposed between a first flat surface and a second flat surface which are parallel to each other, and has a convex cross-section near an inner periphery which is in contact with the first flat surface. A first contact portion, a second contact portion having a convex section in the vicinity of the outer periphery abutting on the second flat surface, and an intermediate wall portion gradually increasing in diameter from the first contact portion to the second contact portion; Wherein the radius of curvature of the second convex contact section is set larger than the radius of curvature of the first convex contact section.
Further, the first contact portion, the intermediate wall portion, and the second contact portion have a moderately curved S-shaped cross section.
Further, the whole is formed by pressing from a thin plate material.
[0006]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail based on the illustrated embodiments.
1 is a sectional front view of a free state (unmounted state), FIG. 2 is an enlarged view of a main part thereof, and FIGS. 3 and 4 are cross-sectional explanatory views of a main part showing a use state.
[0007]
1 to 4, S denotes a metal seal (metal seal) according to the present invention, which is made of spring steel, stainless steel, or other metal, and is formed from a thin plate material by press working (plastic working). This is preferable from the viewpoint of ease of production and cost. In addition, it is also possible to produce by cutting, grinding, etc. It may also be preferable to coat the surface of the seal S with a plating film of silver, gold, copper, tin, etc., a resin film such as PTFE or FEP, or a film of various rubber materials.
[0008]
The metal seal S is interposed between the first flat surface 1 and the second flat surface 2 that are parallel to each other, and is entirely annular. Further, the metal seal S has a first convex contact portion 11 near the inner periphery contacting the first flat surface 1 and a second convex contact portion near the outer periphery contacting the second flat surface 2. 12 and a compression elastically deformable intermediate wall portion 13 which is gradually connected to the second contact portion 12 from the first contact portion 11 in a tapered shape. The portion 13 and the second contact portion 12 have an S-shaped section that is gently curved. In the present invention, the S-shape is defined to include an inverted S-shape {Z-shape}.
[0009]
Thus, it can be said that the metal seal S is in the shape of a substantially truncated conical disc spring formed of a gently curved surface. Thus, the hole 3 is formed at the inner peripheral edge where the first contact portion 11 exists.
Then, in FIG. 2, the radius of curvature Rb of the second convex contact section 12 is set to be larger than the radius of curvature Ra of the first convex contact section 11. That is, it is set so that Rb> Ra.
[0010]
In FIGS. 3 and 4, the two-dot chain line indicates that the distance between the first flat surface 1 and the second flat surface 2 is sufficiently large (open) and the metal seal S has no compression force (clamping force). Te, lightly contacted shows an initial state (position), the contact position between the first contact portion 11 and the first flat surface 1 in the initial state (position) and a _0, a second contact portion 12 and the second flat a contact position between the surface 2 and B _0.
[0011]
Next, as the first flat surface 1 gradually approaches the second flat surface 2 to reduce the gap (dimension) between them {pressing the metal seal S}, FIG. as shown, a first contact portion 11 contacting position a ₁ next to the first flat surface 1, moves ΔHa only radially outward, and a second contact portion 12 contact positions between the second flat surface 2 B _1, and the move ΔHb only radially inward. At this time, the movement amount ΔHb of the second contact portion 12 is larger than the movement amount ΔHa of the first contact portion 11. That is, ΔHb> ΔHa. This is made clearer in FIG.
[0012]
FIG. 4 shows a state in which the first flat surface 1 is further approached to the second flat surface 2 from FIG. 3 to minimize the distance between the two, and the metal seal S is crushed. This 4 Te at a first contact portion 11 contact position of the first flat surface 1 is moved next to A _2, from the initial state (two-dot chain line) DerutaHa only radially outward, and the second contact portion 12 and the contact position between the second flat surface 2 moves B ₂ becomes, from the initial state (two-dot chain line) .DELTA.Hb inward only. It is clear from FIG. 4 that ΔHb> ΔHa.
[0013]
FIGS. 3 and 4 are diagrams showing the elastic deformation of the metal seal S that has been confirmed in the FEM (finite element method) analysis and the test of the actual product (prototype). In addition, the contact surface pressure P in each elastic deformation state (each pressing state) of the first contact portion 11 and the second contact portion 12 is also indicated by a value analyzed by FEM analysis at the same time. By setting the radius of curvature Rb of the second convex contact section 12 to be larger than the radius of curvature Ra of the first convex contact section 11, the contact surface pressure of the second contact section 12 can be sufficiently suppressed. , (Irrespective of ΔHb> ΔHa), it is possible to effectively prevent the abrasion of the second contact portion 12 {generation of metal powder, peeling of the coating layer, etc.}. For example, it is suitable as a seal in the fields of semiconductor manufacturing equipment and ultra-precision equipment in which generation of metal powder and resin powder is extremely disliked.
[0014]
In addition, as shown in FIG. 4 or FIG. 3, the surface pressure P of the first contact portion 11 is sufficiently high, and there is no problem regarding the sealing property (sealing property). On the other hand, the contact pressure of the second contact portion 12 is considered to be low, which is considered to be disadvantageous to the sealing performance (sealing performance). However, since the radius of curvature Rb is set to be sufficiently large, the contact area increases, and the (second flat surface) The contact surface (in contact with 2) becomes wide, and the overall sealing performance (sealing performance) is equivalent to that of the first contact portion 11.
[0015]
3 and 4, the second flat surface 2 is exemplified by a case where the bottom surface of a concave portion (concave groove) opening upward and on the inner diameter side corresponds to the first flat surface 1. The first flat surface 1 may be formed with a bottom surface of a concave portion (concave groove). Alternatively, both the first flat surface 1 and the second flat surface 2 may be configured with the bottom surfaces of the concave portions (grooves).
[0016]
Also, in the state shown in FIG. 3, since the metal seal S is sufficiently elastically deformed, the state shown in FIG. 3 may be a final crushed state (used state). In other words, the present metal seal S has a large tolerance for the crushing allowance in the final use state, and can be sealed in a wide set height range. In FIG. 3 and FIG. There is an advantage that the interval dimension (set height) H of the second flat surface 2 can correspond to a wide range from a large value to a small value. Therefore, even if the dimensional tolerance of the concave portion (concave groove) of the member to be mounted such as the flange is uneven, sufficient sealing performance (sealing performance) can be exhibited. Alternatively, it can be said that the restoration amount is large, and it reliably follows pressure cycles and temperature cycles, etc., exhibits stable sealing properties (sealability), and is reused (if there is no scratch etc.) Is also possible.
[0017]
Further, as shown in FIGS. 3 and 4, the metal seal S performs a compression elastic deformation and a torsional elastic deformation in a combined manner, so that a low fastening force───the first flat surface 1 and the second flat surface 2 The sealing force (seal performance) is sufficiently exhibited due to the low tightening force in the direction in which the pieces are brought close to each other. Utilizing such a low tightening force, it can be applied as a seal material in place of the conventional rubber O-ring, and in particular, can be applied to environments (high-temperature, low-temperature, plasma irradiation, ozone atmosphere, etc.) that cannot be applied with a rubber O-ring. If possible, its application range is vast.
[0018]
The surface of the present metal seal S will be described as follows: (1) plating of silver, gold, copper, tin, etc., (2) coating of various resins such as PTFE and FEP, and (3) coating (coating) of various rubber materials. , (4) super-polishing finish, (5) press working, or cutting or grinding working. The sealed fluid may be vacuum, various gases (CO ₂ , H ₂ , O ₂ , NH ₃ , H ₂ O, etc.), various liquids (H ₂ O, H ₂ SO ₄ , HCl, etc.). In any case, the present metal seal S is an excellent seal in that it has a low tightening force, a large amount of elastic restoration, easy handling, small number of parts, easy manufacturing, and low cost. Therefore, the mating member (flange or the like) to be mounted can be applied to a brittle material such as ceramic or a soft material such as aluminum, or a portion irradiated with plasma or ozone such as a semiconductor manufacturing apparatus. It can be applied to a wide temperature range from low temperature to high temperature. Since it is crushable and exhibits a sufficient sealing property (sealing property) in a wide range of the set height H, it can be applied even if the dimensional accuracy and tolerance of the mating member (flange or the like) to be mounted are rough, and a deep groove can be applied. However, even a shallow groove can sometimes be handled by the common metal seal S. Further, since the elastic recovery amount is large, it can be applied to a place where pressure fluctuation and temperature fluctuation are severe, can be reused, and there is an advantage that handling (incorporation) is easy.
The overall shape (in plan view) of the present metal seal S is not limited to a circular ring shape. For example, a race track type ring shape shown in FIG. 5A or a rectangular type ring shape shown in FIG. And so on.
[0019]
【The invention's effect】
The present invention has the following significant effects by the above configuration.
According to the first aspect, when the seal is mounted, the contact position (see B ₀ and B _{2 in} FIG. 4) at which the second contact portion 12 having a convex cross section abuts (presses) on the second flat surface 2 moves. In this case, generation of wear dust such as coating powder and metal powder can be effectively prevented. Therefore, the seal is suitable for semiconductor manufacturing equipment and ultra-precision equipment.
[0020]
Further, since it can be used with a low tightening force, it can be applied to a material whose handle member (flange or the like) is fragile or soft. Furthermore, since the amount of resilient restoration is large, it is possible to cope with a wide set height (see reference numeral H in FIGS. 3 and 4). Sex). In addition, since the amount of elastic restoration is large, it can cope with large pressure fluctuations and temperature fluctuations, can be reused, and can easily handle assembling work. For example, plasma irradiation or semiconductor-related devices in an ozone atmosphere And can be provided at low cost.
[0021]
(According to claim 2) As shown in FIGS. 3 and 4, the distance between the first flat surface 1 and the second flat surface 2 (set height H) is always stable regardless of the size. The first contact portion 11 and the second contact portion 12 are pressed tightly. In addition, not only mere compression elastic deformation but also torsional elastic deformation is added, thereby realizing a lower tightening force and further increasing the amount of restoration.
(According to claim 3), it is possible to efficiently and inexpensively produce a large amount.
[Brief description of the drawings]
FIG. 1 is a sectional front view showing an embodiment of the present invention.
FIG. 2 is an enlarged view of a main part of FIG.
FIG. 3 is an enlarged sectional explanatory view of a main part showing a use state.
FIG. 4 is an enlarged sectional explanatory view of a main part showing a use state.
FIG. 5 is a plan view showing a modification.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 1st flat surface 2 2nd flat surface 11 1st contact part 12 2nd contact part 13 Intermediate wall part S Metal seal Ra Half curvature Rb Half curvature P Contact surface pressure

Claims (3)

A first convex portion having a cross section convex toward the inner periphery and abutting on the first flat surface, which is entirely interposed between the first flat surface and the second flat surface which are parallel to each other; A second contact portion having a convex section in the vicinity of the outer periphery in contact with the second flat surface, and an intermediate wall portion gradually increasing in diameter from the first contact portion to the second contact portion, and A metal seal, wherein a radius of curvature of the second contact portion is set larger than a radius of curvature of the first contact portion. The metal seal according to claim 1, wherein the first contact portion, the intermediate wall portion, and the second contact portion have a gently curved S-shaped cross section. 3. The metal seal according to claim 1, wherein the entirety is formed by pressing from a thin plate material.

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