Sealing structure using metal seals

Abstract

Even when using metal seals as a substitute for rubber seals, the design ensures that the required sealing performance can be achieved with a low tightening force. [Solution] The seal comprises an annular seal body 2, a pair of fork portions 3 extending radially from one of the inner and outer circumferential surfaces of the seal body such that their tips are separated from each other, and projections 4 formed at the tips of the pair of fork portions, which contact a pair of flat surfaces 11 and 12 to provide sealing performance. The radial width W2 of the seal body is 0.6 mm or more and 1.0 mm or less, the ratio of the thickness t1 before the projection to the thickness t2 at the base of the fork portion is 0.45 or more and 0.70 or less, the ratio of the radial length W1 from the seal body to the tip of the fork portion to the thickness t2 at the base of the fork portion is 0.10 or more and 0.15 or less, and the yield strength is 450 N / mm 2 More than 1000N / mm 2 Below, the tensile strength is 650 N / mm². 2 More than 1400N / mm 2 It is composed of metal materials that meet the following criteria and have an HV hardness of 200 to 450.

Description

Technical Field

[0001] The present invention relates to a sealing structure using a metal sheet. Ru

Background Art

[0002] Conventionally, for example, as disclosed in Patent Document 1, a compression-elasticity deformable U-shaped metal seal mainly made of metal is known. The small protrusions on the outer side of the opening side of this metal seal contact the first and second metal flat surfaces to receive a compressive force and perform a sealing function.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, since the conventional metal seal has been used in applications where internal pressure is applied, the seal body and the fork portion have been made thick to prevent plastic deformation or breakage due to internal pressure.

[0005] Then, in order to deform the fork portion so as to exhibit sealing performance, for example, a high tightening force of 33 to 70 N / mm is required.

[0006] In order to exert such a high tightening force, it is necessary to increase the size and number of fastening bolts compared to the case of a rubber seal, and there is a problem that the device must be significantly changed from the configuration in the case of a rubber seal.

[0007] ​This invention has been made in view of the above, and its purpose is to enable the use of a metal seal as a substitute for a rubber seal, while still providing the necessary sealing performance with a relatively low clamping force, and without requiring significant design changes. [Means for solving the problem]

[0008] To achieve the above objective, this invention makes the seal body and fork portion thinner and uses a metal seal made of a metal material with high mechanical strength. The sealing structure used and did.

[0009] Specifically, the first invention sealing structure using metal seals So, The ring-shaped seal body, A pair of fork portions extending radially from one of the inner and outer circumferential surfaces of the seal body, with their tips separated from each other, Each of the pair of fork sections has a projection formed at its tip that contacts a pair of flat surfaces to provide a sealing effect, The radial width (W2) of the seal body is 0.6 mm or more and 1.0 mm or less. In the fork portion , thickness at the base (t2) against Thickness (t1) of the portion in front of the aforementioned projection The ratio (t1 / t2) is between 0.45 and 0.70, Radial length (W1) from the seal body to the tip against The thickness (t2) at the base of the fork portion. The ratio (t2 / W1) is between 0.10 and 0.15. Yield strength 450N / mm 2 More than 1000N / mm 2 Below, the tensile strength is 650 N / mm². 2 More than 1400N / mm 2 It is composed of the following metal materials with an HV hardness of 200 to 450. The metal seal, When clamped between a pair of flat surfaces, the sealing performance is achieved when only the pair of fork portions are in contact with the pair of flat surfaces, the clamping force between the pair of flat surfaces is 20 N / mm or less, and there is no pressure difference between the inside and outside of the metal seal. .

[0010] According to the above configuration, since the metal seal is composed of a metal material with high mechanical strength and appropriate Vickers hardness (HV hardness), in a situation where the internal pressure is hardly applied, the seal body and the fork portion can be made thinner, and as a result, the necessary seal performance can be ensured with a low fastening force. Even in situations where no internal pressure is applied to the metal seal, and in environments where corrosion resistance is required and rubber seals cannot be used, the necessary sealing performance can be ensured with a low fastening force. "A state in which there is no pressure difference between the inside and outside of the metal seal" does not mean that the pressure difference must be completely zero; a small pressure difference is acceptable.

[0011] In the second invention, in the first invention, In the aforementioned metal seal, At least the protrusion and its periphery are plated with a plating that is softer than the metal material.

[0012] In the above configuration, when plating that is softer than the metal material of the first invention, particularly plating with a Vickers hardness of 80 or less such as tin, is applied, the minute irregularities on the surface of the pair of flat surfaces are filled by the plating, and sufficient seal performance can be exhibited with a smaller reaction force.

Effect of the Invention

[0013] As described above, according to the present invention, even when using a metal seal as an alternative to a rubber seal, the necessary seal performance can be exhibited with a low tightening force. A sealing structure can be obtained. .

Brief Description of the Drawings

[0014] [Figure 1] It is a perspective view showing a metal seal according to an embodiment of the present invention. [Figure 2] It is an enlarged cross-sectional view showing a state where the metal seal is sandwiched between a pair of flat surfaces. [Figure 3] It is a front view showing the metal seal. [Figure 4] It is a plan view showing the metal seal. [Figure 5] It is a cross-sectional view taken along line V-V in FIG. 4. [Figure 6] It is an enlarged cross-sectional view of part VI in FIG. 5. [Figure 7A] It is a table showing the mechanical properties of each material. [Figure 7B] It is a graph showing each material and the reaction force. [Figure 8] This is a table comparing the examples and comparative examples. [Figure 9] This is a cross-sectional view corresponding to Figure 6, relating to Modification Example 1. [Figure 10] This is a cross-sectional view corresponding to Figure 6, relating to Modification 2. [Figure 11] This is a cross-sectional view of the metal seal of Comparative Example 1. [Figure 12] This is a cross-sectional view of the metal seal of Comparative Example 2. [Modes for carrying out the invention]

[0015] Embodiments of the present invention will be described below with reference to the drawings.

[0016] Figure 1 shows a metal seal 1 according to an embodiment of the present invention, which comprises an annular seal body 2 having substantially the same cross-sectional shape continuous in the circumferential direction, and a pair of fork portions 3 extending radially from one of the inner and outer circumferential surfaces of the seal body 2 such that their tips are separated from each other.

[0017] As shown in Figure 2, the tips of these pair of fork portions 3 each have projections 4 that contact a pair of flat surfaces 11 and 12 provided on a pair of piping members or the like to provide a sealing effect. The cross-sectional shape of these projections 4 is semicircular, but it may also be semi-elliptical, triangular, or rectangular.

[0018] In this embodiment, the seal 1 is used in locations where there is no or small pressure difference between the inner and outer diameters, and the radial width W2 of the seal body 2 is 0.6 mm or more and 1.0 mm or less (0.6 ≤ W2 ≤ 1.0). Preferably, the width W2 is 0.7 ≤ W2 ≤ 0. 9 Yes. Therefore, compared to conventional metal seals, the seal body 2 RadialThe width W2 is reduced. The height H2 of the seal body 2 is, for example, 1.76 mm. The shape of the seal body 2 is not particularly limited, but in this embodiment, it is a generally rectangular cross-section that is long in the vertical direction, and chamfers are formed at the four corners of the rectangular cross-section. Even in the usage state shown in Figure 2, the seal body 2 is basically used so as not to touch the pair of flat surfaces 11 and 12.

[0019] And in this embodiment, Thickness t2 at the base of the fork section 3 against Thickness t1 in front of projection 4 The value is between 0.45 and 0.70 (0.45 ≤ t1 / t2 ≤ 0.70). Preferably, it is 0.50 ≤ t1 / t2 ≤ 0.60.

[0020] Also, Radial length W1 from seal body 2 to tip against Thickness t2 at the base of the fork section 3 The ratio is between 0.10 and 0.15 (0.10 ≤ t² / W1 ≤ 0.15).

[0021] In an uncompressed state, the maximum height H1 of the fork section 3 is, for example, 2.41 mm, and the value of t2 / H1 is between 0.100 and 0.125 (0.100 ≤ t2 / H1 ≤ 0.125).

[0022] Metal seal 1 has a yield strength of 450 N / mm². 2 More than 1000N / mm 2 Below, the tensile strength is 650 N / mm². 2 More than 1400N / mm 2 The following materials consist of metallic materials with an HV hardness of 200 to 450. Examples include, but are not limited to, nickel alloy X-750 and carbon steel S45C.

[0023] As shown in Figure 7A, yield strength, tensile strength, and HV hardness decrease in the order of X-750, S45C, and SUS316L. As can be seen from this, the mechanical properties of SUS316L are inferior to those of X-750 and S45C.

[0024] As shown in Figure 7B, a metal seal identical in shape to the metal seal 1, but without plating, is prepared between a pair of flat surfaces 11 and 12, and the reaction force (line load) when the set height is gradually reduced is as follows: X-750, S45C, SU S3 The resistance decreases in the order of 16L. In particular, the reaction force of SUS316L never exceeds 7N / mm, which is insufficient to secure the required line load and therefore cannot provide adequate sealing performance.

[0025] The area including the protrusion 4 and its surroundings may be plated with a material softer than the base material made of the metal. Specifically, plating with tin, silver, nickel, etc. is performed. In particular, when plating with a Vickers hardness of 80 or less, such as tin or silver, is applied, it is thought that the material can easily penetrate due to the surface irregularities of the pair of flat surfaces 11 and 12, and the sealing performance is further improved. The thickness of the plating is not particularly limited, but a plating of an appropriate thickness is applied according to the size of the metal seal 1.

[0026] In the sealing structure of this embodiment shown in Figure 2, when the metal seal 1 is sandwiched between a pair of flat surfaces 11 and 12, the clamping force of the pair of flat surfaces 11 and 12 is 20 N / mm or less, with only the pair of fork portions 3 in contact with the pair of flat surfaces 11 and 12. In this state, sealing performance is achieved with no pressure difference between the inside and outside of the metal seal 1. As a result, the fluid on the inner diameter side and the fluid on the outer diameter side of the metal seal 1, where there is little to no pressure difference, do not mix.

[0027] -Examples- Figure 8 shows a table comparing the metal seals of Example 1, Example 2, Comparative Example 1, and Comparative Example 2 of the present invention.

[0028] Example 1 is a metal seal without plating, as described above for the metal seal 1. Example 2 is the metal seal 1 described above, but with tin plating.

[0029] Comparative Example 1 is a metal seal 101 as shown in Figure 11, in which the width W2 of the seal body 102 is large at 1.40 mm. The height H2 of the seal body 102 is, for example, 1.96 mm. On the other hand, the length W1 of the pair of fork portions 103 is short at 1.40 mm, and the maximum height H1 is 2.41 mm. Compared to Examples 1 and 2, this metal seal 101 is intended for use in applications where internal pressure is applied. This metal seal 101 is silver-plated. The t1 / t2 value of the fork portion 103 is 0.73, and it does not taper as much towards the tip compared to Examples 1 and 2. Thus, it has a relatively rigid structure so that the fork portion 103 does not undergo plastic deformation or break due to internal pressure.

[0030] Comparative Example 2 is a metal seal 201 as shown in Figure 12, used in applications where internal pressure is applied. The seal body 202 is not as thick as the pair of fork portions 203 as in Examples 1 and 2 and Comparative Example 1, with a width W2 of approximately 1.15 mm. The height H2 of the seal body 202 is 3.27 mm. The length W1 of the fork portion 203 is 4.25 mm, and the maximum height H1 is 3.925 mm, which is larger than the other examples. On the other hand, the value of t1 / t2 is 0.85, and it does not become very thin towards the tip. Thus, Comparative Example 2 also has a relatively rigid structure to prevent plastic deformation or fracture of the fork portion 203 due to internal pressure.

[0031] Then, for these examples and comparative examples, as shown in Figure 2, the reaction force was measured when the set height was gradually reduced while the product was sandwiched between a pair of flat surfaces 11 and 12. This allowed us to determine the reaction force at the set height that provided the required sealing performance. For example, in Examples 1 and 2, as shown in Figure 7B, the reaction force was measured when the set height was narrowed from approximately 2.4 mm to 1.9 mm. The reaction force that provided the required sealing performance was 17 N / mm at a set height of 2.00 mm in Example 1, but decreased to 10 N / mm at a set height of 2.32 mm in Example 2, which was tin-plated.

[0032] This is thought to be because the tin in the tin plating is more effective at filling in minute irregularities on the surfaces of the pair of flat surfaces 11 and 12, thus enabling the required sealing performance to be achieved with less force.

[0033] On the other hand, when similar tests were conducted on Comparative Examples 1 and 2, and the set height was lowered until the required sealing performance was achieved, the measured reaction force in Comparative Example 1 was 36-39 N / mm when the set height was 2.10 mm to 2.15 mm, which was more than twice as large as that of Example 1. Furthermore, in Comparative Example 2, the measured reaction force was 50-55 N / mm when the set height was 3.40 mm to 3.45 mm, which was approximately three times larger than that of Example 1.

[0034] Thus, in this embodiment, the metal seal 1 is constructed from a metal material such as X-750, which has high mechanical strength and appropriate HV hardness. Therefore, in situations where there is almost no internal pressure, the seal body 2 and the fork portion 3 can be made thinner, and as a result, the required sealing performance can be ensured with a low fastening force.

[0035] In this embodiment, a plating softer than the base material may be applied to the area including the projection 4 that contacts the pair of flat surfaces 11 and 12 and its surrounding area. In particular, when a plating with a Vickers hardness of 80 or less, such as tin or silver, is applied, minute irregularities on the flange side are filled in by the plating, and sufficient sealing performance is achieved with a smaller reaction force.

[0036] In this embodiment, even in situations where no internal pressure is applied to the metal seal 1, and in environments where greater corrosion resistance than that required for a rubber seal is needed, the necessary sealing performance can be ensured with a low fastening force.

[0037] Therefore, according to this embodiment, even when the metal seal 1 is used as a substitute for a rubber seal, the required sealing performance can be achieved with a low tightening force.

[0038] -Experimental Variation 1- Figure 9 shows a metal seal 1' according to Modification 1 of the embodiment of the present invention, which differs from the above embodiment in that the shape of the seal body 2' is different. In the following modifications, the same reference numerals are used for parts that are the same as in Figures 1 to 6, and their detailed descriptions are omitted.

[0039] In the modified example 1, the seal body 2' of the metal seal 1' has no chamfering, and the inclination of the upper and lower surfaces of the fork portion 3 is continuous with the upper and lower surfaces of the seal body 2'. Even with this shape, the same effects and advantages as in the above embodiment are achieved.

[0040] -Variation 2- Figure 10 shows a metal seal 1'' according to a modified example 2 of the present invention, which differs from the above embodiment in that the shape of the seal body 2'' is different.

[0041] In the modified example 2, the seal body 2'' of the metal seal 1'' has no chamfers on its four corners and is rectangular in shape. Even with this shape, it produces the same effects and advantages as in the above embodiment.

[0042] The embodiments described above are essentially preferred examples and are not intended to limit the scope of the present invention, its applications, or uses. [Explanation of symbols]

[0043] 1. Metal seal 2 Sticker body 3. Fork section 4 Protrusion 11,12 flat surface

Claims

1. The ring-shaped seal body, A pair of fork portions extending radially from one of the inner and outer circumferential surfaces of the seal body, with their tips separated from each other, Each of the pair of fork sections has a projection formed at its tip that contacts a pair of flat surfaces to provide a sealing effect, The radial width (W2) of the seal body is 0.6 mm or more and 1.0 mm or less. The ratio (t1 / t2) of the thickness at the base (t2) of the projection in the fork portion to the thickness at the front (t1) of the projection is 0.45 or more and 0.70 or less. The ratio (t2 / W1) of the radial length W1 from the seal body to the tip to the thickness (t2) of the base of the fork portion is 0.10 or more and 0.15 or less. Proof strength 450N / mm ２ More than 1000N / mm ２ The following is a tensile strength of 650 N / mm ２ More than 1400N / mm ２ It is composed of the following metal materials with an HV hardness of 200 to 450. A metal seal characterized by the following features.

2. At least the protrusion and its surrounding area are plated with a material softer than the metal material. The metal seal according to feature 1.

3. When the metal seal described in claim 1 or 2 is sandwiched between a pair of flat surfaces, the sealing performance is achieved when only the pair of fork portions are in contact with the pair of flat surfaces, the clamping force between the pair of flat surfaces is 20 N / mm or less, and there is no pressure difference between the inside and outside of the metal seal. A sealing structure using a metal seal, characterized by the following features.

Images