Ring-shaped metal gasket seal structure

Abstract

To provide a ring-shaped metal gasket which has a small cross-sectional area, can be applied to a narrower space, and can achieve desirable sealing performance even with small axial force.SOLUTION: A radial inner surface 2 has a flat rectangular cross section, and a chamfer 4 is provided at both corners of a radial outer surface. A ratio of a length of one side of the chamber 4 with respect to a width in a radial direction of the cross section is 0.500 or more and 0.875 or less.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a ring-shaped metal gasket that is sandwiched between a pair of sealed members such as fixed flanges. Seal structure Regarding. [Background technology]

[0002] Conventionally, ring-shaped metal gaskets for fixed flanges for forming a vacuum and sealing against internal and external pressures have been known. As an example of this type of ring-shaped metal gasket, a metal O-ring 101 having a cross-sectional shape as shown in Fig. 6A is known. This metal O-ring 101 is deformed by being fastened by upper and lower flanges 110, 111 as shown in Fig. 6B, for example, and exerts sealing performance by obtaining a reaction force.

[0003] On the other hand, as disclosed in Patent Document 1, a ring-shaped metal gasket with a complex cross-sectional shape is also known, which includes a pair of fork portions extending radially, a connecting portion connecting the base portions of the fork portions, and a lip portion protruding from the tip side of the fork portions in the opposite direction to the compression direction. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-167617 Summary of the Invention [Problem to be solved by the invention]

[0005] The equipment and devices in which this type of ring-shaped metal gasket is used are generally tending to become smaller, and the space allowable for each part is becoming more and more restricted. Ring-shaped metal gaskets are no exception, and there is a demand for products with smaller cross sections that can be used in smaller, limited spaces.

[0006] Furthermore, as equipment and devices become smaller, the size of fastening parts such as bolts also becomes smaller, and the axial force that can be obtained decreases. As a result, it has become necessary for ring-shaped metal gaskets to exhibit sealing performance with a smaller fastening force.

[0007] The present invention has been made in consideration of these points, and its object is to provide a ring-shaped metal gasket that has a small cross-sectional area so that it can be applied to narrower spaces, and that can obtain the desired sealing performance even with a small axial force. [Means for solving the problem]

[0008] In order to achieve the above object, in the present invention, the cross-sectional shape of the ring-shaped metal gasket is devised.

[0009] Specifically, the ring-shaped metal gasket of the first invention is a ring-shaped metal gasket sandwiched between a pair of sealed members, The radially inner surface has a flat rectangular cross section, and both corners of the radially outer surface are chamfered. The ratio of the length of one side of the chamfer to the width in the radial direction of the cross section is 0.500 or more and 0.875 or less.

[0010] Here, if the ratio of the chamfer to the radial length (width) of the rectangular cross section of the ring-shaped metal gasket is less than 0.500, the axial force required for deformation becomes large, and if it is greater than 0.875, the axial force required for deformation becomes small, but there is a concern that the width after deformation will be too large to obtain appropriate sealing performance and interfere with the outer diameter of the groove. However, with the above configuration, appropriate sealing performance can be obtained with a small axial force while preventing the width after deformation from becoming too large. In particular, since the radial inner surface is flat, the width before deformation is small, and it is difficult to expand during deformation, so the increase in width after deformation is also suppressed. In addition, the chamfering is advantageous in that it avoids contact with the R portion of the corner formed during molding of the sealed member. Here, "flat" does not mean a completely flat shape without any unevenness, but means that some unevenness or inclination is acceptable.

[0011] In the second invention, in the first invention, The aspect ratio of the cross section is equal to or greater than 2.0 and equal to or less than 3.5.

[0012] Here, if the aspect ratio of the cross section is made smaller than 2.0, the ratio of the width increases and the axial force required for deformation becomes too large, while if it is made larger than 3.5, there is a concern that the axial force becomes too small and the reaction force required to obtain sealing performance cannot be obtained. In addition, there is a concern that the deformation becomes too easy and the width after deformation becomes too large to obtain appropriate sealing performance, which may interfere with the outer diameter of the groove. However, with the above configuration, appropriate sealing performance can be obtained with a small axial force while preventing the width after deformation from becoming too large.

[0013] In a third aspect of the present invention, in the first or second aspect of the present invention, The angle of the chamfer with respect to the axial direction is equal to or greater than 35° and equal to or less than 55°.

[0014] Here, if the angle of the chamfer with respect to the axial direction is smaller than 35°, the axial force required for deformation when sandwiched between a pair of sealed members becomes large, while if the angle is larger than 55°, the axial force becomes too small, and there is a concern that the reaction force required for sealing performance cannot be obtained. In addition, there is a concern that the sealing surface becomes too sharp, causing the amount of deformation to increase too much and interfering with the outer diameter of the groove. However, with the above configuration, appropriate sealing performance can be obtained with a small axial force while preventing the width after deformation from becoming too large.

[0015] In a fourth aspect of the present invention, in any one of the first to third aspects of the present invention, The ring-shaped metal gasket has a hexagonal cross section with flat radially inner and outer surfaces.

[0016] According to the above-mentioned configuration, it is possible to obtain a ring-shaped metal gasket that has the simplest shape, is easy to form by cutting or shaping, and is easy to reduce the width before and after deformation. Effect of the Invention

[0017] As described above, when the ring-shaped metal gasket of the present invention is sandwiched between a pair of sealed members, the width both before and after deformation is reduced, so that the cross-sectional area is small and it can be applied to narrower spaces, and the desired sealing performance can be obtained with a small axial force while reducing the width after deformation. [Brief description of the drawings]

[0018] [Figure 1] 1 is an enlarged cross-sectional view showing a ring-shaped metal gasket according to an embodiment of the present invention. [Figure 2A] 1 is a front view showing a ring-shaped metal gasket according to an embodiment of the present invention. [Figure 2B] 1 is a plan view showing a ring-shaped metal gasket according to an embodiment of the present invention. [Figure 2C] 1 is a perspective view showing a ring-shaped metal gasket according to an embodiment of the present invention. [Diagram 3] FIG. 3 is an enlarged cross-sectional view taken along line III-III in FIG. 2B. [Figure 4] 1 is a cross-sectional view showing an example of a state in which a ring-shaped metal gasket according to an embodiment of the present invention is used. [Figure 5A] FIG. 1 is a diagram showing the state before deformation of an analysis result performed on a ring-shaped metal gasket according to an embodiment of the present invention. [Figure 5B] FIG. 13 is a diagram showing the state after deformation as a result of an analysis performed on a ring-shaped metal gasket according to an embodiment of the present invention. [Figure 6A] FIG. 13 is a diagram showing the state before deformation of an analysis result performed on a metal O-ring according to the conventional technology (comparative example). [Figure 6B] FIG. 13 is a diagram showing the state after deformation of an analysis result performed on a metal O-ring according to the conventional technology (comparative example). [Figure 7] 1 is a graph comparing load characteristics. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0020] 1 to 3 show a ring-shaped metal gasket 1 according to an embodiment of the present invention, which has a rectangular cross section with flat radially inner side surface 2 and radially outer side surface 3. Here, "flat" does not mean a completely flat shape with no irregularities, but means that some irregularities or inclinations are acceptable.

[0021] Chamfers 4 are provided on both corners of both axial ends of the radially outer surface 3. This gives the ring-shaped metal gasket 1 a flat hexagonal cross section with the radially inner surface 2 and the radially outer surface 3. In principle, the chamfers 4 are symmetrical on both axial sides about the axial midline, but may be asymmetric in some cases. The axially opposite corners formed by the chamfers 4 form sealing surfaces 5 with the sealed member.

[0022] As shown in FIG. 4, for example, the ring-shaped metal gasket 1 is sandwiched between an upper fixed flange 10 and a lower fixed flange 11, which are sealed members, of a mass flow controller used in semiconductor manufacturing equipment, etc., and serves to seal fluids such as gas and liquid between the two.

[0023] This chamfer 4 is not a small chamfer such as a light chamfer that is simply used to remove sharpness, but a ratio (L / W) of the length L of one side of the chamfer 4 to the radial length of the cross section (i.e., width W) of 0.500 to 0.875 (0.500≦L / W≦0.875), which is relatively large compared to the width W. Here, the length L of one side refers to the length of one side on the side that contacts the sealing surface of the sealed member (the axial end face side). The provision of this chamfer 4 is advantageous in that it can avoid contact with, for example, the R portion 12 of the corner formed during molding of the lower fixed flange 11.

[0024] If the ratio of the chamfer 4 to the radial width (width W) of the rectangular cross section of the ring-shaped metal gasket 1 is made smaller than 0.500, the axial force required for deformation increases, and if it is made larger than 0.875, the axial force decreases, but there is a concern that the width W after deformation will become too large to obtain appropriate sealing performance and will interfere with the outer diameter of the groove in the lower fixed flange 11. However, if 0.500≦L / W≦0.875 as in this embodiment, appropriate sealing performance can be obtained with a small axial force while preventing the width after deformation from becoming too large.

[0025] In this embodiment, the cross-sectional height H of the ring-shaped metal gasket 1 is greater than the width W, and the aspect ratio (H / W) is 2.0 to 3.5 (2.3≦H / W≦3.5).

[0026] If the aspect ratio of the cross section is made smaller than 2.0, the proportion of the width W increases and the axial force required for deformation increases, whereas if it is made larger than 3.5, the proportion of the width W decreases and deformation becomes easier, but there is a concern that the axial force becomes too small and the reaction force required to obtain sealing performance cannot be obtained. In addition, in order to obtain appropriate sealing performance, the width W after deformation may become too large and may interfere with the outer diameter of the groove of the lower fixed flange 11. However, if 2.3≦H / W≦3.5 as in this embodiment, appropriate sealing performance can be obtained with a small axial force while preventing the width W after deformation from becoming too large.

[0027] In this embodiment, the angle θ of the chamfer 4 with respect to the axial direction is equal to or greater than 35° and equal to or less than 55° (35°≦θ≦55°).

[0028] If the angle of the chamfer 4 with respect to the axial direction is smaller than 35°, the axial force required for deformation becomes large, and if it is larger than 55°, the amount of deformation becomes too large, which may cause a concern of interfering with the outer diameter of the groove in the lower fixed flange 11. However, if the angle is 35°≦θ≦55° as in this embodiment, appropriate sealing performance can be obtained with a small axial force while preventing the width after deformation from becoming too large.

[0029] In this embodiment, for example, the length L of one side is 0.30 mm, the height H is 0.8 mm, the angle θ is 45°, and the outer diameter is 20.25 mm. These dimensions can be changed within the above ranges depending on the application. The outer diameter of the ring-shaped metal gasket 1 is not particularly limited, but is relatively small, for example, about 5 mm to 45 mm.

[0030] The ring-shaped metal gasket 1 is machined, for example, from a round bar or a round pipe such as SUS316L, and processed by cutting. The processing of the chamfer 4 may be performed at any stage. The material of the ring-shaped metal gasket 1 is not limited to SUS316L, and any suitable metal may be selected according to the application. The ring-shaped metal gasket 1 of this embodiment has a very simple shape, with a basic rectangular cross section and a chamfer 4 formed on the radially outer surface 3 to form a hexagonal shape, and therefore has the advantage of being easy to process and easy to manufacture, for example, when machined from a round bar or a round pipe and shaped by cutting.

[0031] --Example-- Next, the results of a simulation comparing the load characteristics of the ring-shaped metal gasket 1 according to this embodiment as an example and a conventional metal O-ring 101 as a comparative example will be described with reference to FIGS. 5A to 7. FIG.

[0032] First, in terms of the cross-sectional shape, in the shape of a set height of 0.855 mm, which is the distance between the flat upper and lower flanges 110, 111 set for the simulation before compression, as shown in FIG. 6A, the metal O-ring 101 of the comparative example has a circular shape with an outer diameter D0 of 0.855 mm and a wall thickness t0 of 0.25 mm.

[0033] On the other hand, as shown in FIG. 5A, the width W of the ring-shaped metal gasket 1 of the embodiment is 0.355 mm, and the height H is 0.855 mm. Even when comparing the widths alone, the width W of the ring-shaped metal gasket 1 of the embodiment is smaller than half the width (outer diameter D0) of the metal O-ring (W <D0 / 2)。

[0034] When the distance between the upper and lower flanges 110, 111 is narrowed and the set height is reduced to 0.60 mm, as shown in FIG. 6B, metal O-ring 101 of the comparative example is crushed and its width expands evenly on both sides, increasing by about 10 to 20 percent.

[0035] On the other hand, in the ring-shaped metal gasket 1 of the embodiment, the upper and lower intermediate portions of the radially inner surface 2 hardly bulge, and the upper and lower sealing surfaces 5 portions of the radially inner surface 2 expand, and the distance between the radially inner surface 2 and the radially outer surface 3 does not increase much. In this way, the original width W is small, and the increase in the width W after deformation is also suppressed.

[0036] Next, the load characteristics of the Example and Comparative Example are shown in Figure 7. It was found that when the distance (set height) between the upper and lower sealed members was reduced, the Comparative Example had a slightly larger compressive load, but the Example also showed similar load characteristics.

[0037] It can be seen that in the embodiment, even though the width W before deformation is made smaller than half that of the comparative example, a compression load equivalent to that of the comparative example with a larger width can be obtained.

[0038] In this way, the ring-shaped metal gasket 1 according to this embodiment can be applied to a narrower space with a small cross-sectional area because the width W before and after deformation is suppressed when the ring-shaped metal gasket 1 is sandwiched between a pair of sealed members. In addition, the desired sealing performance can be obtained with a small axial force while suppressing the width W after deformation. Therefore, the required sealing performance can be ensured even when the axial force obtained by the fastening force of a small bolt or the like is limited.

[0039] (Other embodiments) The present invention may have the following configurations with respect to the above-described embodiment.

[0040] That is, in the above embodiment, the ring-shaped metal gasket 1 is sandwiched between the upper fixed flange 10 and the lower fixed flange 11 of the mass flow controller, and its use for sealing a fluid such as a gas between the two has been described; however, the present invention is not limited to this, and the fluid to be sealed may be a liquid, and the use is not particularly limited.

[0041] It should be noted that the above-described embodiments are essentially preferred examples, and are not intended to limit the scope of the present invention, its applications, or uses. [Explanation of symbols]

[0042] 1 Ring-shaped metal gasket 2 Radial inner surface 3 Radial outer surface 4 Chamfering 5 Sealing Surface 10 Upper fixed flange (sealed component) 11 Lower fixed flange (sealed component) 12 R section 101 Metal O-ring (Comparative example) 110 Flange 111 Flange

Claims

1. The radially inner surface has a flat rectangular cross section, and both corners of the radially outer surface are chamfered. A ring-shaped metal gasket having a ratio of the length of one side of the chamfer to the width in the radial direction of the cross section of 0.500 to 0.875 is sandwiched between a pair of sealed members having flat sealed surfaces, and only the radially inner side of the deformed chamfer comes into contact with the sealed surfaces, and the radially outer side does not come into contact with the sealed surfaces. A sealing structure of a ring-shaped metal gasket.

2. The aspect ratio of the cross section of the ring-shaped metal gasket is 2.0 or more and 3.5 or less.

2. The sealing structure of the ring-shaped metal gasket according to claim 1.

3. In the ring-shaped metal gasket, the angle of the chamfer with respect to the axial direction is 35° or more and 55° or less.

2. The sealing structure of the ring-shaped metal gasket according to claim 1.

4. In the ring-shaped metal gasket, the radially inner surface and the radially outer surface are flat hexagonal in cross section.

4. The sealing structure of a ring-shaped metal gasket according to claim 1, wherein the ring-shaped metal gasket is a metal gasket having a ring-shaped groove.

Images