Sealing structure using metal seal

Abstract

To provide a seal that exhibits necessary sealing performance with a low tightening force even when a metal seal is used as a substitute for a rubber seal. [Solution] The seal comprises an annular seal body 2, a pair of fork sections 3 extending radially from one of the inner and outer peripheral surfaces of the seal body so that their tips are spaced apart, and protrusions 4 formed at the tips of the pair of fork sections, which abut against a pair of flat surfaces 11, 12 to exhibit sealing performance. The seal body has a radial width W2 of 0.6 mm to 1.0 mm, a ratio of the thickness t2 at the base of the fork sections to the thickness t1 before the protrusions to the thickness t2 is 0.45 to 0.70, and a ratio of the radial length W1 from the seal body to the tip of the fork sections to the thickness t2 at the base of the fork sections to the thickness t2 is 0.10 to 0.15, and a yield strength of 450 N / mm 2 More than 1000N / mm 2 Tensile strength: 650N / mm 2 More than 1400N / mm 2 and is made of a metal material with an HV hardness of 200 or more and 450 or less.

Description

[Technical Field]

[0001] The present invention is a metal sheet Lu This relates to the sealing structure used. [Background technology]

[0002] Conventionally, a metal seal that is made primarily of metal and has a U-shaped cross section and is capable of compressive elastic deformation has been known, as shown in Patent Document 1. Small protrusions on the outer side of the opening of this metal seal come into contact with first and second metal flat surfaces and receive compressive force, thereby providing a sealing effect. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-24838 Summary of the Invention [Problem to be solved by the invention]

[0004] However, conventional metal seals were used in applications where internal pressure was applied, and so the seal body and fork portion were made thick to prevent them from being plastically deformed or broken by the internal pressure.

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

[0006] In order to achieve such a high tightening force, the size and number of fastening bolts must be increased compared to the case of rubber seals, which poses the problem of requiring significant changes to the device configuration from that of rubber seals.

[0007] The present invention was made in consideration of these points, and its purpose is to provide a seal that can exhibit the required sealing performance with a relatively low tightening force even when a metal seal is used in place of a rubber seal, and that can be used without requiring major design changes. [Means for solving the problem]

[0008] In order to achieve the above object, in this invention, the seal body and the fork portion are made thin, and the metal seal is made of a metal material with high mechanical strength. The sealing structure used did.

[0009] Specifically, the first invention Sealing structure using metal seal So, an annular seal body; a pair of fork portions extending radially from one of the inner circumferential surface and the outer circumferential surface of the seal body such that their tips are spaced apart from each other; a protrusion formed at each tip of the pair of fork portions, the protrusion abutting against the pair of flat surfaces to exhibit sealing performance; The radial width (W2) of the seal body is 0.6 mm or more and 1.0 mm or less, In the fork portion , base thickness (t2) against Thickness before the protrusion (t1) The ratio (t1 / t2) is 0.45 or more and 0.70 or less, The radial length from the seal body to the tip (W1) against The thickness of the base of the fork (t2) The ratio (t2 / W1) is 0.10 or more and 0.15 or less, Yield strength 450N / mm 2 More than 1000N / mm 2 Tensile strength: 650N / mm 2 More than 1400N / mm 2 and metallic materials with hardness of 200 to 450 HV The metal seal When sandwiched between a pair of flat surfaces, the clamping force of the pair of flat surfaces is 20 N / mm or less with only the pair of fork parts in contact with the pair of flat surfaces, and sealing performance is demonstrated when there is no pressure difference between the inside and outside of the metal seal. .

[0010] According to the above configuration, the metal seal is made of a metal material that has high mechanical strength and an appropriate Vickers hardness (HV hardness). Therefore, in situations where there is almost no internal pressure, the seal body and fork portion can be made thin, and as a result, the required sealing performance can be ensured with a low tightening force. The required sealing performance can be ensured with low fastening force even in situations where no internal pressure is applied to the metal seal, or in environments where corrosion resistance is required and rubber seals cannot be used. "A state where there is no pressure difference between the inside and outside of the metal seal" does not mean that the pressure difference needs to be completely zero, but rather that some pressure difference is acceptable.

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

[0012] In the above configuration, when the metal material is plated with a material softer than the metal material of the first invention, particularly tin or the like having a Vickers hardness of 80 or less, minute irregularities on the surfaces of the pair of flat faces are filled with the plating, and sufficient sealing performance can be achieved with a smaller reaction force. [Effects of the Invention]

[0013] As described above, according to the present invention, even when a metal seal is used in place of a rubber seal, the required sealing performance can be achieved with a low tightening force. A sealed structure can be obtained . [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a perspective view showing a metal seal according to an embodiment of the present invention. [Figure 2] FIG. 4 is an enlarged cross-sectional view showing a state in which the metal seal is sandwiched between a pair of flat surfaces. [Figure 3] FIG. [Figure 4] FIG. 2 is a plan view showing a metal seal. [Figure 5] FIG. 5 is a cross-sectional view taken along line VV in FIG. [Figure 6] FIG. 6 is an enlarged cross-sectional view of a portion VI in FIG. 5. [Figure 7A] 1 is a table showing the mechanical properties of each material. [Figure 7B] 10 is a graph showing the reaction force of each material. [Figure 8] 1 is a table comparing examples and comparative examples. [Figure 9] FIG. 7 is a cross-sectional view corresponding to FIG. 6 according to a first modified example. [Figure 10] FIG. 10 is a cross-sectional view corresponding to FIG. 6 according to a second modified example. [Figure 11] FIG. 1 is a cross-sectional view of a metal seal of Comparative Example 1. [Figure 12] FIG. 10 is a cross-sectional view of a metal seal of Comparative Example 2. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0016] FIG. 1 shows a metal seal 1 according to an embodiment of the present invention. This metal seal 1 comprises an annular seal body 2 having a substantially identical cross-sectional shape that continues in the circumferential direction, and a pair of fork portions 3 that extend radially from one of the inner and outer peripheral surfaces of the seal body 2 so that their tips are spaced apart.

[0017] 2, a protrusion 4 is formed at each tip of the pair of fork portions 3, and the protrusion 4 abuts against a pair of flat surfaces 11, 12 provided on a pair of piping members or the like to provide sealing performance. The cross-sectional shape of the protrusion 4 is semicircular, but it may also be semi-elliptical, triangular, or rectangular.

[0018] In this embodiment, the metal seal 1 is used in a location where there is little or no pressure difference between the inner and outer diameter sides, 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 mm). Preferably, the width W2 is 0.7 ≦ W2 ≦ 0. 9 in Therefore, the seal body 2 has a smaller diameter than the conventional metal seal. RadialThe width W2 is small. 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 has a generally rectangular cross section that is long in the vertical direction, and the four corners of the rectangular cross section are chamfered. Even in the use state shown in Figure 2, the seal body 2 is generally used so as not to come into contact with the pair of flat surfaces 11, 12.

[0019] In this embodiment, Thickness t2 of the base of the fork part 3 against Thickness t1 before protrusion 4 is 0.45 or more and 0.70 or less (0.45≦t1 / t2≦0.70), and preferably 0.50≦t1 / t2≦0.60.

[0020] Also, Radial length W1 from seal body 2 to tip against Thickness t2 of the base of the fork part 3 The ratio is 0.10 or more and 0.15 or less (0.10≦t2 / W1≦0.15).

[0021] In an uncompressed state, the fork portion 3 has a maximum height H1 of, for example, 2.41 mm, and the value of t2 / H1 is equal to or greater than 0.100 and equal to or less than 0.125 (0.100≦t2 / H1≦0.125).

[0022] Metal seal 1 has a yield strength of 450N / mm 2 More than 1000N / mm 2 Tensile strength: 650N / mm 2 More than 1400N / mm 2 The following is made of a metal material having an HV hardness of 200 or more and 450 or less. Examples include nickel alloy X-750 and carbon steel S45C, but are not limited to these.

[0023] As shown in Figure 7A, the 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 FIG. 7B, a metal seal made of each material and having the same shape as the metal seal 1 and not plated is prepared between a pair of flat surfaces 11 and 12, and the reaction force (line load) when the set height is gradually narrowed is S3 The reaction force of SUS316L in particular does not exceed 7N / mm, so the required line load cannot be secured and sufficient sealing performance cannot be achieved.

[0025] The area including the protrusion 4 and its surroundings may be plated with a material softer than the base metal material. Specifically, plating with tin, silver, nickel, or the like is performed. In particular, when plating with a Vickers hardness of 80 or less, such as tin or silver, is performed, it is believed that the plating easily penetrates into the uneven surfaces of the pair of flat surfaces 11, 12, further improving sealing performance. The thickness of the plating is not particularly limited, but 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 Fig. 2, when the metal seal 1 is sandwiched between the pair of flat surfaces 11, 12, the clamping force of the pair of flat surfaces 11, 12 is 20 N / mm or less with only the pair of fork portions 3 in contact with the pair of flat surfaces 11, 12. In this state, sealing performance is achieved with no pressure difference inside or outside 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 no or almost no pressure difference, do not mix.

[0027] -Example- FIG. 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 that is not plated as compared to the above-described metal seal 1. Example 2 is the above-described metal seal 1 that is tin-plated.

[0029] Comparative Example 1 is a metal seal 101 as shown in FIG. 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 value of t1 / t2 of the fork portions 103 is 0.73, which is not significantly tapered toward the tip compared to Examples 1 and 2. As such, the fork portions 103 have a relatively high rigidity structure to prevent plastic deformation or fracture due to internal pressure.

[0030] Comparative Example 2 is a metal seal 201 as shown in FIG. 12, used in applications where internal pressure is applied. The seal body 202 is not as thick as the pair of fork portions 203 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, making it larger than the other examples. Meanwhile, the value of t1 / t2 is 0.85, meaning that the seal does not taper significantly toward the tip. Thus, Comparative Example 2 also has a relatively high rigidity structure to prevent the fork portions 203 from plastically deforming or breaking due to internal pressure.

[0031] Then, for these examples and comparative examples, the reaction force was measured when the set height was gradually reduced while the sample was sandwiched between a pair of flat surfaces 11 and 12, as shown in FIG. 2 . This determined the reaction force at the set height at which the required sealing performance was exhibited. For example, in the case of Examples 1 and 2, the reaction force was measured when the set height was narrowed from approximately 2.4 mm to 1.9 mm, as shown in FIG. 7B . The reaction force at which the required sealing performance was exhibited 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 can more easily fill in minute irregularities on the surfaces of the pair of flat surfaces 11, 12, and therefore the required sealing performance can be achieved with a small force.

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

[0034] In this way, in this embodiment, the metal seal 1 is made of 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 fork portion 3 can be made thin, and as a result, the required sealing performance can be ensured with a low tightening force.

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

[0036] In this embodiment, even in a situation where no internal pressure is applied to the metal seal 1 or in an environment where greater corrosion resistance than that of a rubber seal is required, the required sealing performance can be ensured with a low tightening force.

[0037] Therefore, according to the metal seal 1 of 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] -Variation 1- 9 shows a metal seal 1' according to a first modification 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 parts as those in FIGS. 1 to 6 are designated by the same reference numerals, and detailed description thereof will be omitted.

[0039] The seal body 2' of the metal seal 1' according to Modification 1 is not chamfered, and the slopes of the upper and lower surfaces of the fork portion 3 are continuous with the upper and lower surfaces of the seal body 2'. This shape also achieves the same effects as the above embodiment.

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

[0041] The seal body 2'' of the metal seal 1'' according to the second modification has a rectangular shape with no chamfers at the four corners. Even with this shape, the same effects as those of the above embodiment can be achieved.

[0042] 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]

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

Claims

1. an annular seal body; a pair of fork portions extending radially from one of the inner circumferential surface and the outer circumferential surface of the seal body such that their tips are spaced apart from each other; a protrusion formed at each tip of the pair of fork portions, the protrusion abutting against the pair of flat surfaces to exhibit sealing performance; The radial width (W2) of the seal body is 0.6 mm or more and 1.0 mm or less, In the fork portion, the ratio (t1 / t2) of the thickness (t2) at the base to the thickness (t1) at the front of the protrusion is 0.45 or more and 0.70 or less, The ratio (t2 / W1) of the thickness (t2) of the base of the fork portion to the radial length (W1) from the seal body to the tip is 0.10 or more and 0.15 or less, Proof strength 450N / mm ２ More than 1000N / mm ２ Tensile strength 650 N / mm ２ More than 1400N / mm ２ and a metal seal made of a metal material having a hardness of 200 or more and 450 or less, When sandwiched between a pair of flat surfaces, with only the pair of fork parts in contact with the pair of flat surfaces, the clamping force of the pair of flat surfaces is 20 N / mm or less, and sealing performance is exhibited when there is no pressure difference between the inside and outside of the metal seal. A sealing structure using a metal seal.

2. At least the protrusion and its periphery in the metal seal are plated with a material softer than the metal material.

2. A sealing structure using the metal seal according to claim 1.

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