Gasket and sealing structure
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-11-27
- Publication Date
- 2026-04-14
Smart Images
Figure 00000000_0000_ABST
Abstract
Description
[Technical field]
[0001] The present disclosure relates to gaskets and sealing structures. [Background technology]
[0002] For example, gaskets that provide a seal between two members are known, as disclosed in Japanese Patent Application Laid-Open No. 2016-038076 and Japanese Patent Application Laid-Open No. 2015-4394. Summary of the Invention [Problem to be solved by the invention]
[0003] Gaskets are sometimes used in water-rich environments that contain aqueous solutions of sodium chloride, calcium chloride, etc. In such environments, even when a gasket is attached to an aluminum member, it is desirable that the member not be corroded by water.
[0004] An object of the present disclosure is to provide a gasket and a sealing structure that can suppress corrosion of a component to which it is attached and extend the life of the component. [Means for solving the problem]
[0005] A first aspect of the present disclosure is A ring-shaped gasket made of an elastomer that contacts an inner peripheral surface of a hole in an outer member and an outer peripheral surface of an inner member to separate an atmospheric space from an internal space of the outer member, A first wide portion, A cylindrical first large diameter outer peripheral surface that contacts the inner peripheral surface of the hole over a length of 0.1 mm or more in the axial direction of the gasket; a cylindrical first small diameter inner peripheral surface that contacts the outer peripheral surface of the inner member over a length of 0.1 mm or more in the axial direction of the gasket; A first end surface; a first outer corner formed by the first large diameter outer peripheral surface and the first end surface, the first outer corner having a radius of curvature of 0.5 mm or less in a cross section including an axis of the gasket; a first inner corner formed by the first small diameter inner circumferential surface and the first end surface, the first inner corner having a radius of curvature of 0.5 mm or less in a cross section including an axis of the gasket; A first wide portion having A second wide portion, A cylindrical second large diameter outer peripheral surface that contacts the inner peripheral surface of the hole over a length of 0.1 mm or more in the axial direction of the gasket; a cylindrical second small diameter inner peripheral surface that contacts the outer peripheral surface of the inner member over a length of 0.1 mm or more in the axial direction of the gasket; A second end surface; a second outer corner formed by the second large diameter outer peripheral surface and the second end surface, the second outer corner having a radius of curvature of 0.5 mm or less in a cross section including an axis of the gasket; a second inner corner formed by the second small diameter inner circumferential surface and the second end surface, the second inner corner having a radius of curvature of 0.5 mm or less in a cross section including an axis of the gasket; A second wide portion having A third wide portion, a third large diameter outer peripheral surface in contact with the inner peripheral surface of the hole, the third large diameter outer peripheral surface having an interference of 0.05 mm or more with respect to the inner peripheral surface of the hole; a third small diameter inner circumferential surface in contact with the outer circumferential surface of the inner member, the third small diameter inner circumferential surface having an interference of 0.05 mm or more with respect to the outer circumferential surface of the inner member; A third wide portion having A first narrow portion is interposed between the first wide portion and the third wide portion, a first small diameter outer circumferential surface spaced from the inner circumferential surface of the hole, the first small diameter outer circumferential surface having a first outer circumferential groove; a first large diameter inner circumferential surface spaced from the outer circumferential surface of the inner member, the first large diameter inner circumferential surface having a first inner circumferential groove; A first narrow portion having A second narrow portion is interposed between the second wide portion and the third wide portion, a second smaller diameter outer circumferential surface spaced from the inner circumferential surface of the hole, the second smaller diameter outer circumferential surface having a second outer circumferential groove; a second large diameter inner circumferential surface spaced from the outer circumferential surface of the inner member, the second large diameter inner circumferential surface having a second inner circumferential groove; A second narrow portion having having When the gasket is compressed between the outer member and the inner member, the maximum distance between the first outer peripheral groove and the inner peripheral surface of the hole, the maximum distance between the second outer peripheral groove and the inner peripheral surface of the hole, the maximum distance between the first inner peripheral groove and the outer peripheral surface of the inner member, and the maximum distance between the second inner peripheral groove and the outer peripheral surface of the inner member are 0.05 mm or more. It is a gasket.
[0006] A second aspect of the present disclosure is A ring-shaped gasket made of an elastomer that contacts an inner peripheral surface of a hole in an outer member and an outer peripheral surface of an inner member to separate an atmospheric space from an internal space of the outer member, A first wide portion, A cylindrical first large diameter outer circumferential surface; A cylindrical first small diameter inner circumferential surface; A first wide portion having A second wide portion, A cylindrical second large diameter outer circumferential surface; A cylindrical second small diameter inner circumferential surface; A second wide portion having A third wide portion, a third major outer peripheral surface having a diameter greater than a diameter of the first major outer peripheral surface and a diameter of the second major outer peripheral surface when the gasket is not compressed between the outer member and the inner member; a third minor diameter inner circumferential surface having a diameter smaller than a diameter of the first minor diameter inner circumferential surface and a diameter of the second minor diameter inner circumferential surface when the gasket is not compressed between the outer member and the inner member; A third wide portion having A first narrow portion is interposed between the first wide portion and the third wide portion, a first small diameter outer circumferential surface having a first outer circumferential groove; a first large diameter inner circumferential surface having a first inner circumferential groove; A first narrow portion having A second narrow portion is interposed between the second wide portion and the third wide portion, a second small diameter outer circumferential surface having a second outer circumferential groove; a second large diameter inner circumferential surface having a second inner circumferential groove; A second narrow portion having having In the axial direction of the gasket, the length of the cylindrical portion of the first large diameter outer circumferential surface, the length of the cylindrical portion of the first small diameter inner circumferential surface, the length of the cylindrical portion of the second large diameter outer circumferential surface, and the length of the cylindrical portion of the second small diameter inner circumferential surface are greater than the length of the cylindrical portion of the third large diameter outer circumferential surface and the length of the cylindrical portion of the third small diameter inner circumferential surface. It is a gasket.
[0007] A third aspect of the present disclosure is The gasket; The outer member; The inner member; It is a sealed structure having the above structure. [Brief description of the drawings]
[0008] [Figure 1] FIG. 1 is a front view of a gasket according to an embodiment; [Diagram 2] 1 is a cross-sectional view of a sealing structure having a gasket according to an embodiment; [Diagram 3] FIG. 1 is an enlarged cross-sectional view of a gasket according to an embodiment of the present invention; [Figure 4] FIG. 1 is an enlarged cross-sectional view of an embodiment of a gasket showing the outer and inner members in phantom; [Diagram 5] Schematic cross-sectional diagram showing water infiltration into the gap between a typical gasket and a component [Figure 6] Cross-sectional view of a sealing structure having a gasket according to Comparative Example 1 [Figure 7] Cross-sectional view of a sealing structure having a gasket of Comparative Example 2 [Figure 8]Graph showing relative life spans of gaskets according to the embodiment and comparative examples 1 and 2 [Figure 9] A cross-sectional view showing a defect when the gasket of Comparative Example 3 is disposed between an outer member and an inner member. [Figure 10] A cross-sectional view showing a defect when the gasket of Comparative Example 4 is disposed between an outer member and an inner member. [Figure 11] Enlarged cross-sectional view of a gasket according to the first modification [Figure 12] Enlarged cross-sectional view of a gasket according to modified example 2 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0009] Various embodiments of the present disclosure will now be described with reference to the accompanying drawings, in which the drawings are not necessarily to scale and some features may be exaggerated or omitted.
[0010] As shown in Fig. 1, the gasket 1 of this embodiment is annular and has a through hole 2 therein. The gasket 1 has a shape that is rotationally symmetric about a central axis line Ax.
[0011] 2, the gasket 1 is disposed between an outer member 3 and an inner member 4. The gasket 1 contacts an inner circumferential surface 3A of a hole in the outer member 3 and an outer circumferential surface 4C of the inner member 4. The gasket 1 separates an atmospheric space A from an internal space B of the outer member 3. The outer member 3 is, for example, a housing of a machine or structure. The inner member 4 is, for example, a tube. Both the outer member 3 and the inner member 4 are made of metal (for example, aluminum).
[0012] The inner member 4 has a large diameter portion 4A on the atmospheric space A side. The inner member 4 has a large diameter portion 4B on the internal space B side. The inner member 4 has a circumferential groove 4D between the large diameter portions 4A and 4B. The gasket 1 is disposed in the circumferential groove 4D. The large diameter portions 4A and 4B may be flanges. Moreover, the large diameter portion 4A, the large diameter portion 4B, and the circumferential groove 4D may be omitted.
[0013] The gasket 1 is used in an environment where the atmospheric space A contains a lot of water, including aqueous solutions of sodium chloride, calcium chloride, etc. Therefore, the gasket 1 has a role of preventing or reducing the intrusion of foreign matter, particularly water, from the atmospheric space A to the internal space B. For example, foreign matter such as water advances toward the gasket 1 through the gap between the large diameter portion 4A of the inner member 4 and the inner circumferential surface 3A of the hole in the outer member 3, as shown by arrow F.
[0014] The gasket 1 is made of a general elastomer (including rubber). For example, the gasket 1 is made of EPDM (ethylene propylene diene rubber), acrylic rubber, nitrile rubber, or fluororubber, and is preferably made of an elastomer having high water resistance or salt resistance. Preferred elastomers having high water resistance or salt resistance are, for example, EPDM and fluororubber.
[0015] 3 is an enlarged cross-sectional view of the gasket 1 in a cross section including the central axis Ax when the gasket 1 is not in use and is not compressed between the outer member 3 and the inner member 4. As shown in FIG. 3, the gasket 1 has a first wide portion 11, a second wide portion 12, a third wide portion 13, a first narrow portion 14, and a second narrow portion 15.
[0016] The first wide portion 11 is located at a first end in the axial direction of the gasket 1. The first wide portion 11 has a cylindrical first large diameter outer peripheral surface 11A, a cylindrical first small diameter inner peripheral surface 11B, and a first end face 11E. The "axial direction" refers to the direction of the central axis Ax. The first end face 11E is an end face in the axial direction of the gasket 1 and is flat. The first wide portion 11 has an outer corner 11C (first outer corner) and an inner corner 11D (first inner corner). The outer corner 11C is formed by the first large diameter outer peripheral surface 11A and the first end face 11E. The inner corner 11D is formed by the first small diameter inner peripheral surface 11B and the first end face 11E.
[0017] The second wide portion 12 is located at a second end in the axial direction of the gasket 1. The second wide portion 12 has a cylindrical second large-diameter outer peripheral surface 12A, a cylindrical second small-diameter inner peripheral surface 12B, and a second end face 12E. The second end face 12E is an end face in the axial direction of the gasket 1 and is flat. The second wide portion 12 has an outer corner 12C (second outer corner) and an inner corner 12D (second inner corner). The outer corner 12C is formed by the second large-diameter outer peripheral surface 12A and the second end face 12E. The inner corner 12D is formed by the second small-diameter inner peripheral surface 12B and the second end face 12E.
[0018] The third wide portion 13 is located in the center of the gasket 1 in the axial direction. The third wide portion 13 has a third large-diameter outer peripheral surface 13A and a third small-diameter inner peripheral surface 13B. As shown in FIG. 3, when the third wide portion 13 is not compressed between the outer member 3 and the inner member 4, the third large-diameter outer peripheral surface 13A has a semicircular shape protruding radially outward in a cross section including the central axis Ax. The third small-diameter inner peripheral surface 13B has a semicircular shape protruding radially inward in a cross section including the central axis Ax.
[0019] The first narrow width portion 14 is interposed between the first wide width portion 11 and the third wide width portion 13. The first narrow width portion 14 has a first small diameter outer peripheral surface 14A and a first large diameter inner peripheral surface 14B. The first small diameter outer peripheral surface 14A has a first outer peripheral groove 14C. The first large diameter inner peripheral surface 14B has a first inner peripheral groove 14D.
[0020] The first outer peripheral groove 14C is smoothly connected to the third large diameter outer peripheral surface 13A in a cross section including the central axis Ax, and has a substantially semicircular portion and an inclined portion. The substantially semicircular portion is recessed radially inward. The inclined portion is smoothly connected to the first large diameter outer peripheral surface 11A. The first inner circumferential groove 14D has a substantially semicircular portion and an inclined portion in a cross section including the central axis Ax. The substantially semicircular portion is smoothly connected to the third small diameter inner circumferential surface 13B and is recessed radially outward. The inclined portion is smoothly connected to the first small diameter inner circumferential surface 11B.
[0021] The second narrow width portion 15 is interposed between the second wide width portion 12 and the third wide width portion 13. The second narrow width portion 15 has a second small diameter outer peripheral surface 15A and a second large diameter inner peripheral surface 15B. The second small diameter outer peripheral surface 15A has a second outer peripheral groove 15C. The second large diameter inner peripheral surface 15B has a second inner peripheral groove 15D.
[0022] The second outer peripheral groove 15C has a substantially semicircular portion and an inclined portion in a cross section including the central axis Ax. The substantially semicircular portion is smoothly connected to the third large diameter outer peripheral surface 13A. The inclined portion is smoothly connected to the second large diameter outer peripheral surface 12A. The second inner circumferential groove 15D has a substantially semicircular portion and an inclined portion in a cross section including the central axis Ax. The substantially semicircular portion is smoothly connected to the third small diameter inner circumferential surface 13B. The inclined portion is smoothly connected to the second small diameter inner circumferential surface 12B.
[0023] Preferably, the shape of the gasket 1 in a cross section including the central axis Ax (the cross-sectional shape in FIG. 3) is line-symmetric with respect to the vertical axis X of the cross section. Also, preferably, the shape of the gasket 1 in a cross section including the central axis Ax (the cross-sectional shape in FIG. 3) is line-symmetric with respect to the horizontal axis Y of the cross section. Therefore, the gasket 1 has a mirror-symmetric shape with respect to a plane perpendicular to the central axis Ax (a plane including the horizontal axis Y).
[0024] 4, the effect of arranging the first wide portion 11 on the atmospheric space A side and the second wide portion 12 on the internal space B side is equivalent to the effect of arranging the first wide portion 11 on the internal space B side and the second wide portion 12 on the atmospheric space A side. Therefore, an operator handling the gasket 1 does not need to pay attention to the orientation of the gasket 1.
[0025] However, the gasket 1 does not have to be completely mirror-symmetric with respect to a plane perpendicular to the central axis Ax. For example, if the second narrow width portion 15 and the first narrow width portion 14 have similar dimensions and shapes, and the second wide width portion 12 and the first wide width portion 11 have similar shapes and dimensions, the effect of arranging the first wide width portion 11 on the atmospheric space A side and the second wide width portion 12 on the internal space B side is substantially the same as the effect of arranging the first wide width portion 11 on the internal space B side and the second wide width portion 12 on the atmospheric space A side.
[0026] Fig. 4 shows the gasket 1 in use, with the gasket 1 disposed between the outer member 3 and the inner member 4. In Fig. 4, the outer member 3 and the inner member 4 are shown in phantom lines, and the contour of the gasket 1 in the non-use state (uncompressed state) that is the same as that in Fig. 3 is shown in solid lines. Fig. 4 shows the shape of the gasket 1 in a cross section including the central axis line Ax. The contour of the gasket 1 compressed between the outer member 3 and the inner member 4 is shown in phantom lines.
[0027] In the first wide portion 11, the first large diameter outer peripheral surface 11A is in surface contact with the inner peripheral surface 3A of the hole of the outer member 3. At room temperature (e.g., 20°C), the diameter D1 of the first large diameter outer peripheral surface 11A in an uncompressed state is equal to the diameter d1 of the inner peripheral surface 3A of the hole. Therefore, the interference In1 of the first large diameter outer peripheral surface 11A with respect to the inner peripheral surface 3A of the hole is 0 mm.
[0028] In the first wide portion 11, the first small diameter inner circumferential surface 11B is in surface contact with the outer circumferential surface 4C of the inner member 4. At room temperature, a diameter D2 of the first small diameter inner circumferential surface 11B in an uncompressed state is equal to a diameter d2 of the outer circumferential surface 4C of the inner member 4. Therefore, the interference In2 of the first small diameter inner circumferential surface 11B with respect to the outer circumferential surface 4C of the inner member 4 is 0 mm.
[0029] In the second wide portion 12, the second large diameter outer peripheral surface 12A is in surface contact with the inner peripheral surface 3A of the hole in the outer member 3. At room temperature, the diameter D1 of the second large diameter outer peripheral surface 12A in an uncompressed state is equal to the diameter d1 of the inner peripheral surface 3A of the hole. Therefore, the interference In1 of the second large diameter outer peripheral surface 12A with respect to the inner peripheral surface 3A of the hole is 0 mm.
[0030] In the second wide portion 12, the second small diameter inner circumferential surface 12B is in surface contact with the outer circumferential surface 4C of the inner member 4. At room temperature, a diameter D2 of the second small diameter inner circumferential surface 12B in an uncompressed state is equal to a diameter d2 of the outer circumferential surface 4C of the inner member 4. Therefore, the interference In2 of the second small diameter inner circumferential surface 12B with respect to the outer circumferential surface 4C of the inner member 4 is 0 mm.
[0031] Therefore, when the gasket 1 is disposed between the outer member 3 and the inner member 4, the dimensions of the first wide portion 11 and the second wide portion 12 hardly change.
[0032] In the uncompressed state, the radius of curvature R of the outer corners 11C, 12C of the first wide portion 11 and the second wide portion 12 and the inner corners 11D, 12D of the first wide portion 11 and the second wide portion 12 is 0.5 mm or less. Since the interferences In1, In2 are 0 mm, the radius of curvature R of the gasket 1 in the compressed state is almost the same as the radius of curvature R in the uncompressed state.
[0033] In the third wide portion 13, the third large diameter outer peripheral surface 13A is in surface contact with the inner peripheral surface 3A of the hole of the outer member 3. The diameter of the third large diameter outer peripheral surface 13A in the uncompressed state is larger than the diameter D1. The maximum diameter D3 of the third large diameter outer peripheral surface 13A is larger than the diameter D1 and the diameter d1. Preferably, the interference In3 of the third large diameter outer peripheral surface 13A with respect to the inner peripheral surface 3A of the hole, that is, (D3-d1) / 2, is 0.05 mm or more. Therefore, the third large diameter outer peripheral surface 13A has a higher ability to block the progress of water than the first large diameter outer peripheral surface 11A and the second large diameter outer peripheral surface 12A.
[0034] The third small diameter inner circumferential surface 13B is in surface contact with the outer circumferential surface 4C of the inner member 4. The diameter of the third small diameter inner circumferential surface 13B in the uncompressed state is smaller than the diameter D2. The minimum diameter D4 of the third small diameter inner circumferential surface 13B is smaller than the diameter D2 and the diameter d2. Preferably, the interference In4 of the third small diameter inner circumferential surface 13B with respect to the outer circumferential surface 4C of the inner member 4, that is, (d2-D4) / 2, is 0.05 mm or more. Therefore, the third small diameter inner circumferential surface 13B has a higher ability to block the progress of water than the first small diameter inner circumferential surface 11B and the second small diameter inner circumferential surface 12B.
[0035] When the gasket 1 is disposed between the outer member 3 and the inner member 4, the dimensions of the first wide portion 11 and the second wide portion 12 are hardly changed. On the other hand, the third large diameter outer peripheral surface 13A is compressed and deformed by the inner peripheral surface 3A of the hole of the outer member 3 as shown by the imaginary line, and the third large diameter outer peripheral surface 13A becomes a shape that matches the inner peripheral surface 3A of the hole. The diameter of the third large diameter outer peripheral surface 13A is reduced to d1 of the inner peripheral surface 3A of the hole. Also, the third small diameter inner peripheral surface 13B is compressed and deformed by the outer peripheral surface 4C of the inner member 4 as shown by the imaginary line, and the third small diameter inner peripheral surface 13B becomes a shape that matches the outer peripheral surface 4C. The diameter of the third small diameter inner peripheral surface 13B is expanded to the diameter d2 of the outer peripheral surface 4C of the inner member 4.
[0036] When the gasket 1 is disposed between the outer member 3 and the inner member 4, in the first narrow width portion 14, the first small diameter outer peripheral surface 14A does not contact the inner peripheral surface 3A of the hole of the outer member 3. Furthermore, the first large diameter inner peripheral surface 14B does not contact the outer peripheral surface 4C of the inner member 4. However, as the third large diameter outer peripheral surface 13A deforms, the first small diameter outer peripheral surface 14A and the first outer peripheral groove 14C deform as shown by the imaginary lines. Furthermore, as the third small diameter inner peripheral surface 13B deforms, the first large diameter inner peripheral surface 14B and the first inner peripheral groove 14D deform.
[0037] When the gasket 1 is disposed between the outer member 3 and the inner member 4, the maximum distance e1 between the first outer peripheral groove 14C (imaginary line after deformation) and the inner peripheral surface 3A of the hole in the compressed state is preferably 0.05 mm or more. The maximum distance e2 between the first inner peripheral groove 14D (imaginary line after deformation) and the outer peripheral surface 4C of the inner member 4 in the compressed state is preferably 0.05 mm or more.
[0038] When the gasket 1 is disposed between the outer member 3 and the inner member 4, in the second narrow width portion 15, the second small diameter outer peripheral surface 15A does not contact the inner peripheral surface 3A of the hole of the outer member 3. In addition, the second large diameter inner peripheral surface 15B does not contact the outer peripheral surface 4C of the inner member 4. However, as the third large diameter outer peripheral surface 13A deforms, the second small diameter outer peripheral surface 15A and the second outer peripheral groove 15C deform as shown by the imaginary lines. In addition, as the third small diameter inner peripheral surface 13B deforms, the second large diameter inner peripheral surface 15B and the second inner peripheral groove 15D deform.
[0039] When the gasket 1 is disposed between the outer member 3 and the inner member 4, the maximum distance e1 between the second outer peripheral groove 15C (imaginary line after deformation) and the inner peripheral surface 3A of the hole in the compressed state is preferably 0.05 mm or more. The maximum distance e2 between the second inner peripheral groove 15D (imaginary line after deformation) and the outer peripheral surface 4C of the inner member 4 in the compressed state is preferably 0.05 mm or more.
[0040] The maximum distances e1, e2 are preferably 0.05 mm or more even when the gasket 1, the outer member 3 and the inner member 4 undergo thermal expansion.
[0041] In the axial direction of the gasket 1, the length L1 of the cylindrical portion of the first large diameter outer surface 11A, the length L2 of the cylindrical portion of the first small diameter inner surface 11B, the length L1 of the cylindrical portion of the second large diameter outer surface 12A, and the length L2 of the cylindrical portion of the second small diameter inner surface 12B are longer than the length L3 of the cylindrical portion of the third large diameter outer surface 13A and the length L4 of the cylindrical portion of the third small diameter inner surface 13B. Therefore, it is possible to ensure large lengths in the axial direction of the gasket 1: length L1 over which the first large diameter outer peripheral surface 11A contacts the inner peripheral surface 3A of the hole, length L2 over which the first small diameter inner peripheral surface 11B contacts the outer peripheral surface 4C of the inner member 4, length L1 over which the second large diameter outer peripheral surface 12A contacts the inner peripheral surface 3A of the hole, and length L2 over which the second small diameter inner peripheral surface 12B contacts the outer peripheral surface 4C of the inner member 4. The lengths L1 and L2 are preferably 0.1 mm or more.
[0042] FIG. 5 shows a schematic diagram of water intrusion into a gap between a general gasket 20 and a member 21. It is assumed that a water droplet 22 in the atmospheric space A adheres to a corner 23 of the gasket 20. Then, water easily intrudes into a minute gap (not shown) at the interface K between the member 21 and the gasket 20. The arrow f in the figure shows the direction of water movement. Water moves slowly through the minute gap at the interface K due to capillary action. If the water remains at the interface K for a long time, corrosion at the interface K of the member 21 progresses quickly. Even if the amount of retained water is small, corrosion of the member 21 progresses. If the amount of retained water is small, corrosion of the member 21 is often accelerated compared to when the amount of retained water is large.
[0043] Here, it is considered that when the radius of curvature r of the corner 23 is large, the penetration of water into the gap is promoted. This is because when the radius of curvature r is large, large water droplets tend to adhere to the corner 23, and the length of the acute angled portion S between the corner 23 and the member 21, which is the starting point of penetration into the interface K, becomes large.
[0044] As shown in Fig. 4, it is assumed that the first wide portion 11 is disposed on the atmospheric space A side and the second wide portion 12 is disposed on the internal space B side, and water arrives at the gasket 1 from the atmospheric space A as indicated by the arrow F. In Fig. 4, the atmospheric space A is at the top and the internal space B is at the bottom, but the relative positions of the spaces A and B are not limited to those shown in the figure. For example, the atmospheric space A and the internal space B may be disposed in a horizontal direction.
[0045] Water reaches the first wide portion 11 from the atmospheric space A. However, the radius of curvature R of the outer corner 11C and the inner corner 11D of the first wide portion 11 is small, 0.5 mm or less. Therefore, the intrusion of water from the atmospheric space A into the gap between the outer member 3 and the first wide portion 11 (the gap between the inner peripheral surface 3A of the hole and the first large diameter outer peripheral surface 11A) and the gap between the inner member 4 and the first wide portion 11 (the gap between the outer peripheral surface 4C of the inner member 4 and the first small diameter inner peripheral surface 11B) is suppressed, and corrosion of the outer member 3 and the inner member 4 is suppressed. When the radius of curvature R is larger than 0.5 mm, more water intrudes into the gap between the inner peripheral surface 3A of the hole and the first large diameter outer peripheral surface 11A, and the gap between the outer peripheral surface 4C and the first small diameter inner peripheral surface 11B.
[0046] Even if water infiltrates from the atmospheric space A into the space between the first small diameter outer peripheral surface 14A and the inner peripheral surface 3A of the hole through the gap between the outer member 3 and the first wide portion 11, the first outer peripheral groove 14C is large, i.e., the maximum distance e1 between the first outer peripheral groove 14C and the inner peripheral surface 3A of the hole is 0.05 mm or more. Therefore, corrosion of the outer member 3 is suppressed. This is because, even if water remains in contact with the inner peripheral surface 3A of the hole, corrosion is suppressed if the amount of water is relatively large.
[0047] Furthermore, even if water infiltrates from the atmospheric space A into the space between the first large-diameter inner circumferential surface 14B and the outer circumferential surface 4C of the inner member 4 through the gap between the inner member 4 and the first wide portion 11, the first inner circumferential groove 14D is large, i.e., the maximum distance e2 between the first inner circumferential groove 14D and the outer circumferential surface 4C of the inner member 4 is 0.05 mm or more. Therefore, corrosion of the inner member 4 is suppressed. This is because, even if water remains in contact with the outer circumferential surface 4C of the inner member 4, corrosion is rather suppressed if the amount of water is relatively large. If the distances e1 and e2 are less than 0.05 mm, the amount of stagnant water is small, and corrosion is likely to progress.
[0048] The length L1 over which the first large diameter outer peripheral surface 11A contacts the inner peripheral surface 3A of the hole is 0.1 mm or more, which is sufficiently large. Therefore, the shape of the first outer peripheral groove 14C between the first large diameter outer peripheral surface 11A and the third large diameter outer peripheral surface 13A is stable, and the maximum distance e1 is ensured. In addition, the length L2 over which the first small diameter inner peripheral surface 11B contacts the outer peripheral surface 4C of the inner member 4 is 0.1 mm or more, which is sufficiently large. Therefore, the shape of the first inner peripheral groove 14D between the first small diameter inner peripheral surface 11B and the third small diameter inner peripheral surface 13B is stable, and the maximum distance e2 is ensured. If the lengths L1, L2 are less than 0.1 mm, the first outer peripheral groove 14C and the first inner peripheral groove 14D will be significantly deformed, and the maximum distances e1, e2 will be less than 0.05 mm.
[0049] Furthermore, even if water infiltrates into the space between the first small diameter outer surface 14A and the inner peripheral surface 3A of the hole, the interference In3 of the third large diameter outer surface 13A with respect to the inner peripheral surface 3A of the hole is 0.05 mm, which is sufficiently large, so that water is unlikely to infiltrate into the space between the second small diameter outer surface 15A and the inner peripheral surface 3A of the hole through the gap between the third large diameter outer surface 13A and the inner peripheral surface 3A of the hole. Even if water infiltrates into the space between the first large diameter inner circumferential surface 14B and the outer circumferential surface 4C of the inner member 4, the interference In4 of the third small diameter inner circumferential surface 13B with respect to the outer circumferential surface 4C is 0.05 mm, which is sufficiently large. Therefore, water is unlikely to infiltrate into the space between the second large diameter inner circumferential surface 15B and the outer circumferential surface 4C of the inner member 4 through the gap between the third small diameter inner circumferential surface 13B and the outer circumferential surface 4C of the inner member 4. In this way, corrosion of the outer member 3 and the inner member 4 can be suppressed, and the life span of the outer member 3 and the inner member 4 can be extended.
[0050] The second narrow portion 15 has the same or similar shape and dimensions as the first narrow portion 14. The second wide portion 12 has the same or similar shape and dimensions as the first wide portion 11. Therefore, the above effect can be achieved even when the first wide portion 11 is disposed on the internal space B side and the second wide portion 12 is disposed on the atmospheric space A side.
[0051] The cross-sectional width of the gasket 1, i.e., the difference between the outer maximum radius D3 / 2 and the inner minimum radius D4 / 2 of the gasket 1, (D3-D4) / 2, is not limited, but is preferably 1 mm to 4 mm. The diameter d1 of the inner peripheral surface 3A of the hole of the outer member 3 is not limited, but is preferably about 10 mm to about 40 mm. The diameter d2 of the outer peripheral surface 4C of the inner member 4 is not limited, but is preferably about 8 mm to about 38 mm. The axial length T of the gasket 1 is not limited, but is preferably 2 mm to 5 mm.
[0052] The inventors conducted an experiment to confirm the corrosion suppression effect of the gasket 1 of the embodiment on the outer member 3 and the inner member 4. In the experiment, the diameter d1 of the inner circumferential surface 3A of the hole of the outer member 3 is 18.98 mm. The diameter d2 of the outer circumferential surface 4C of the inner member 4 is 15.18 mm.
[0053] The axial length T of the gasket 1 is 3.5 mm. The radius of curvature R of the outer corner 11C and the inner corner 11D of the first wide portion 11 in the uncompressed state is 0.2 mm. The contact lengths L1, L2 of the first wide portion 11 and the third wide portion 13 are 1.1 mm. The maximum diameter D3 of the third large diameter outer peripheral surface 13A is 19.6 mm. The minimum diameter D4 of the third small diameter inner peripheral surface 13B is 14.8 mm. The difference between the outer maximum radius D3 / 2 and the inner minimum radius D4 / 2 of the gasket 1 is 2.4 mm. The diameter D1 of the first large diameter outer surface 11A and the second large diameter outer surface 12A is equal to the diameter d1 of the inner surface 3A of the hole, which is 18.98 mm. The diameter D2 of the second large diameter outer surface 12A and the second small diameter inner surface 12B is equal to the diameter d2 of the outer surface 4C of the inner member 4, which is 15.18 mm.
[0054] Therefore, when the gasket 1 is placed between the outer member 3 and the inner member 4, the inner diameter expansion rate (d2-D4) / D4 = 0.026, and the radial compression rate of the gasket 1 is [(D3-D4)-(d1-d2)] / (D3-D4) = 0.21.
[0055] As Comparative Example 1, a gasket 31 shown in Fig. 6 was prepared. The gasket 31 is an O-ring. The gasket 31 in an uncompressed state is shown in the lower part of Fig. 6. The outer diameter D13 of the gasket 31 in an uncompressed state is 19.6 mm, and the inner diameter D14 is 14.8 mm. The diameter of the cross section (circular shape) including the central axis Ax of the gasket 31 in an uncompressed state is 2.4 mm.
[0056] Therefore, when the gasket 31 is placed between the outer member 3 and the inner member 4, the inner diameter expansion rate (d2-D14) / D14=0.026, and the radial compression rate of the gasket 31 is [(D13-D14)-(d1-d2)] / (D13-D14)=0.21.
[0057] As Comparative Example 2, a gasket 41 shown in FIG. 7 was prepared. The gasket 41 is an X-ring. The gasket 41 in an uncompressed state is shown at the bottom of FIG. 7. The radius of curvature R1 of the corner of the gasket 41 in an uncompressed state is 0.4 mm. The maximum outer diameter D23 of the gasket 41 in an uncompressed state is 19.6 mm, and the minimum inner diameter D24 is 14.8 mm. The width of the cross section (X-shaped) including the central axis Ax of the gasket 41 in an uncompressed state is 2.4 mm, and the height of the gasket 41 in an uncompressed state is 2.4 mm.
[0058] Therefore, when the gasket 41 is placed between the outer member 3 and the inner member 4, the inner diameter expansion rate (d2-D24) / D24=0.026, and the radial compression rate of the gasket 41 is [(D23-D24)-(d1-d2)] / (D23-D24)=0.21.
[0059] In the experiment, salt water was sprayed using a small sprinkler and supplied from the atmospheric space A toward the gaskets 1, 31, 41 in use through the annular gap CL between the inner circumferential surface 3A of the hole in the outer member 3 and the large diameter portion 4A of the inner member 4. The width of the gap CL (the distance between the inner circumferential surface 3A and the large diameter portion 4A) was 0.075 mm.
[0060] In the experiment, after supplying salt water, the members 3 and 4 and the gaskets 1, 31, and 41 were dried, then humidified with a humidifier, dried again, and then exposed to the atmosphere. In the exposed state, the outer member 3 and the inner member 4 were visually inspected to see whether corrosion had occurred at the specified locations. For the gasket 1 of the embodiment, the predetermined location is a portion of the inner circumferential surface 3A of the hole of the outer member 3 facing the second small diameter outer circumferential surface 15A, and a portion of the outer circumferential surface 4C of the inner member 4 facing the second large diameter inner circumferential surface 15B. For the gasket 31 of the comparative example 1, the predetermined location is a portion of the inner circumferential surface 3A of the hole of the outer member 3 on the inner space B side of the gasket 31, and a portion of the outer circumferential surface 4C of the inner member 4 on the inner space B side of the gasket 31. For the gasket 41 of the comparative example 2, the predetermined location is a portion of the inner circumferential surface 3A of the hole of the outer member 3 on the inner space B side of the gasket 41, and a portion of the outer circumferential surface 4C of the inner member 4 on the inner space B side of the gasket 41.
[0061] In the experiment, a cycle of supplying salt water, drying, humidifying, drying, and releasing to the atmosphere was repeated, and the number of cycles was measured until corrosion occurred at specified locations on the outer member 3 and the inner member 4. The duration of one cycle was 24 hours.
[0062] FIG. 8 shows the experimental results. The relative life on the vertical axis of FIG. 8 is the number of cycles at which corrosion occurs at a given location when each gasket is used, with the number of cycles at which corrosion occurs at a given location when gasket 31, an O-ring, is set to 1.0. As is clear from FIG. 8, the lifespans of gasket 31, an O-ring, and gasket 41, an X-ring, were almost the same. In contrast, the lifespan of gasket 1 of the embodiment was more than twice as long as the lifespans of gaskets 31 and 41 of comparative examples 1 and 2.
[0063] As described above, according to this embodiment, corrosion of the outer member 3 and the inner member 4 can be suppressed, and the life span of the outer member 3 and the inner member 4 can be extended.
[0064] According to this embodiment, even when the radius of curvature R is less than 0.5 mm, the maximum distances e1, e2 are less than 0.05 mm, the contact lengths L1, L2 are less than 0.1 mm, and the clamping margins In3, In4 are less than 0.05 mm, it is possible to suppress corrosion of the outer member 3 and the inner member 4 and extend the life of the outer member 3 and the inner member 4.
[0065] In this embodiment, when the first wide portion 11 is arranged on the atmospheric space A side and the second wide portion 12 is arranged on the internal space B side, even if water infiltrates from the atmospheric space A into the space between the first small diameter outer surface 14A and the inner surface 3A of the hole through the gap between the outer member 3 and the first large diameter outer surface 11A, corrosion of the outer member 3 is suppressed because the first small diameter outer surface 14A has a first outer peripheral groove 14C formed therein. Furthermore, even if water infiltrates from the atmospheric space A into the space between the first large diameter inner surface 14B and the outer peripheral surface 4C of the inner member 4 through the gap between the inner member 4 and the first small diameter inner surface 11B, corrosion of the inner member 4 is suppressed because the first inner peripheral groove 14D is formed in the first large diameter inner surface 14B.
[0066] If the length of the columnar portion of the first large diameter outer peripheral surface 11A is relatively large, the length L1 over which the first large diameter outer peripheral surface 11A contacts the inner peripheral surface 3A of the hole becomes large, and the shape of the first outer peripheral groove 14C between the first large diameter outer peripheral surface 11A and the third large diameter outer peripheral surface 13A becomes stable. Furthermore, if the length of the columnar portion of the first small diameter inner circumferential surface 11B is relatively large, the length L2 over which the first small diameter inner circumferential surface 11B contacts the outer circumferential surface 4C becomes large, and the shape of the first inner circumferential groove 14D between the first small diameter inner circumferential surface 11B and the third small diameter inner circumferential surface 13B becomes stable.
[0067] Even if water infiltrates into the space between the first small diameter outer surface 14A and the inner peripheral surface 3A of the hole, the maximum diameter D3 of the third large diameter outer surface 13A is larger than the diameter D1 of the first large diameter outer surface 11A and the second large diameter outer surface 12A, so the interference In3 of the third large diameter outer surface 13A with respect to the inner peripheral surface 3A of the hole becomes large. Therefore, water is less likely to infiltrate into the space between the second small diameter outer surface 15A and the inner peripheral surface 3A of the hole through the gap between the third large diameter outer surface 13A and the inner peripheral surface 3A of the hole. Even if water infiltrates into the space between the first large diameter inner circumferential surface 14B and the outer circumferential surface 4C of the inner member 4, the minimum diameter D4 of the third small diameter inner circumferential surface 13B is smaller than the diameter D2 of the first small diameter inner circumferential surface 11B and the second small diameter inner circumferential surface 12B, so the interference In4 of the third small diameter inner circumferential surface 13B with respect to the outer circumferential surface 4C becomes large. Therefore, water is unlikely to infiltrate into the space between the second large diameter inner circumferential surface 15B and the outer circumferential surface 4C through the gap between the third small diameter inner circumferential surface 13B and the outer circumferential surface 4C.
[0068] Therefore, corrosion of the outer member 3 and the inner member 4 can be suppressed, and the life span of the outer member 3 and the inner member 4 can be extended.
[0069] The second narrow portion 15 has the same or similar shape as the first narrow portion 14. The second wide portion 12 has the same or similar shape as the first wide portion 11. Therefore, the above-mentioned effect can be achieved even when the first wide portion 11 is disposed on the internal space B side and the second wide portion 12 is disposed on the atmospheric space A side.
[0070] In the embodiment, the diameter D1 of the first large diameter outer peripheral surface 11A and the second large diameter outer peripheral surface 12A in the uncompressed state is equal to the diameter d1 of the inner peripheral surface 3A of the hole of the outer member 3. Therefore, the interference In1 of the first large diameter outer peripheral surface 11A with respect to the inner peripheral surface 3A of the hole and the interference In1 of the second large diameter outer peripheral surface 12A with respect to the inner peripheral surface 3A of the hole are 0 mm. Further, a diameter D2 of the first small diameter inner circumferential surface 11B and the second small diameter inner circumferential surface 12B in a non-compressed state is equal to a diameter d2 of the outer circumferential surface 4C of the inner member 4. Therefore, the interference In2 of the first small diameter inner circumferential surface 11B relative to the outer circumferential surface 4C and the interference In2 of the second small diameter inner circumferential surface 12B relative to the outer circumferential surface 4C are 0 mm.
[0071] For this reason, the gasket 1 can be easily disposed between the inner circumferential surface 3A of the hole and the outer circumferential surface 4C of the inner member 4. In particular, when the gasket 1 is disposed between the inner circumferential surface 3A of the hole in the outer member 3 and the outer circumferential surface 4C of the inner member 4, even if a frictional force acts in the axial direction of the gasket 1, the first wide portion 11 and the second wide portion 12 are unlikely to deform in either the axial or radial directions, and the sealing ability of the gasket 1 is unlikely to be impaired.
[0072] FIG. 9 shows a defect when the gasket 51 of Comparative Example 3 is disposed between the outer member 3 and the inner member 4. In the gasket 51, the diameters of the first large diameter outer peripheral surface 11A and the second large diameter outer peripheral surface 12A in the uncompressed state are larger than the diameter d1 of the inner peripheral surface 3A of the hole of the outer member 3. Therefore, the tightening margin of the first large diameter outer peripheral surface 11A to the inner peripheral surface 3A of the hole and the tightening margin of the second large diameter outer peripheral surface 12A to the inner peripheral surface 3A of the hole are larger than 0 mm. Moreover, the diameters of the first small diameter inner peripheral surface 11B and the second small diameter inner peripheral surface 12B in the uncompressed state are smaller than the diameter d2 of the outer peripheral surface 4C of the inner member 4. Therefore, the tightening margin of the first small diameter inner peripheral surface 11B to the outer peripheral surface 4C and the tightening margin of the second small diameter inner peripheral surface 12B to the outer peripheral surface 4C are larger than 0 mm.
[0073] When the gasket 51 is disposed between the outer member 3 and the inner member 4, the gasket 51 is slid along the central axis Ax against the inner peripheral surface 3A of the hole of the outer member 3, as shown by the arrow P, while being in contact with the outer peripheral surface 4C of the inner member 4. In this case, a large frictional force acts on the first large-diameter outer peripheral surface 11A and the second large-diameter outer peripheral surface 12A due to the inner peripheral surface 3A of the hole of the outer member 3. In addition, a large frictional force acts on the first small-diameter inner peripheral surface 11B and the second small-diameter inner peripheral surface 12B due to the outer peripheral surface 4C of the inner member 4. Therefore, the first wide portion 11 and the second wide portion 12 are greatly deformed in the axial direction. In addition, the entire gasket 51 including the third wide portion 13 is also greatly deformed in the axial direction. As a result, the diameter of the third large-diameter outer peripheral surface 13A decreases, and the diameter of the third small-diameter inner peripheral surface 13B increases. This reduces the interference between the third large diameter outer peripheral surface 13A and the inner peripheral surface 3A of the hole of the outer member 3. Also, this reduces the interference between the third small diameter inner peripheral surface 13B and the outer peripheral surface 4C. This reduces the sealing ability of the gasket 51.
[0074] Furthermore, if the outer corner portion 11C becomes caught in the annular gap CL between the inner circumferential surface 3A of the hole of the outer member 3 and the large diameter portion 4A of the inner member 4, unexpected stress may be generated inside the gasket 51. As a result, the gasket 51 is pulled radially outward toward the atmospheric space A, and the sealing ability of the gasket 51 is impaired. In contrast, the gasket 1 of the embodiment can prevent these problems.
[0075] The gasket 1 of the embodiment may be disposed between an outer member 63 and an inner member 64 shown in FIG. 10, and may be in contact with an inner circumferential surface 63C of a hole in the outer member 63 and an outer circumferential surface 64A of the inner member 64, thereby separating the atmospheric space A from the internal space B of the outer member 63. The outer member 63 is, for example, a housing for a machine or structure. The inner member 64 is, for example, a tube. Both the outer member 63 and the inner member 64 are formed of metal (for example, aluminum). The outer member 63 has a large diameter portion 63A on the atmospheric space A side, and a large diameter portion 63B on the internal space B side. The gasket 1 is disposed in an inner circumferential groove 63D between the large diameter portions 63A and 63B. The large diameter portions 63A and 63B may be flanges.
[0076] FIG. 10 shows a defect when the gasket 61 of Comparative Example 4 is disposed between the outer member 63 and the inner member 64. In the gasket 61, the diameters of the first large diameter outer peripheral surface 11A and the second large diameter outer peripheral surface 12A in the uncompressed state are larger than the diameter d1 of the inner peripheral surface 63C of the hole of the outer member 63. Therefore, the tightening margin of the first large diameter outer peripheral surface 11A to the inner peripheral surface 63C of the hole and the tightening margin of the second large diameter outer peripheral surface 12A to the inner peripheral surface 63C of the hole are larger than 0 mm. Moreover, the diameters of the first small diameter inner peripheral surface 11B and the second small diameter inner peripheral surface 12B in the uncompressed state are smaller than the diameter d2 of the outer peripheral surface 64A of the inner member 64. Therefore, the tightening margin of the first small diameter inner peripheral surface 11B to the outer peripheral surface 64A of the inner member 64 and the tightening margin of the second small diameter inner peripheral surface 12B to the outer peripheral surface 64A of the inner member 64 are larger than 0 mm.
[0077] When the gasket 61 is disposed between the outer member 63 and the inner member 64, the gasket 61 is slid along the central axis Ax against the inner peripheral surface 63C of the hole of the outer member 63, as shown by the arrow Q, while being in contact with the inner peripheral surface 63C of the hole of the outer member 63. In this case, a large frictional force acts on the first large-diameter outer peripheral surface 11A and the second large-diameter outer peripheral surface 12A due to the inner peripheral surface 63C of the hole of the outer member 63. In addition, a large frictional force acts on the first small-diameter inner peripheral surface 11B and the second small-diameter inner peripheral surface 12B due to the outer peripheral surface 64A of the inner member 64. Therefore, the first wide portion 11 and the second wide portion 12 are greatly deformed in the axial direction. In addition, the entire gasket 61 including the third wide portion 13 is also greatly deformed in the axial direction. As a result, the diameter of the third large-diameter outer peripheral surface 13A decreases, and the diameter of the third small-diameter inner peripheral surface 13B increases. This reduces the interference between the third large diameter outer peripheral surface 13A and the inner peripheral surface 63C of the hole of the outer member 63. Also, this reduces the interference between the third small diameter inner peripheral surface 13B and the outer peripheral surface 64A of the inner member 64. This reduces the sealing ability of the gasket 61.
[0078] Furthermore, if the inner corner portion 11D becomes caught in the annular gap CL2 between the large diameter portion 63A of the outer member 63 and the outer circumferential surface 64A of the inner member 64, unexpected stress may be generated inside the gasket 61. As a result, the gasket 61 is pulled toward the atmospheric space A and radially inward, and the sealing ability of the gasket 61 is impaired. In contrast, the gasket 1 of the embodiment can prevent these problems.
[0079] 3 and 4, when the gasket 1 is not compressed between the outer member 3 and the inner member 4, the third large diameter outer circumferential surface 13A has a semicircular shape that protrudes radially outward in a cross section including the axis of the gasket 1. Also, the third small diameter inner circumferential surface 13B has a semicircular shape that protrudes radially inward in a cross section including the axis of the gasket 1.
[0080] Therefore, when the gasket 1 is placed between the inner surface 3A of the hole in the outer member 3 and the outer surface 4C of the inner member 4, even if the gasket 1 is slid against the outer member 3 or the inner member 4, the amount of deformation of the third wide portion 13 due to friction is kept to a minimum.
[0081] Although preferred embodiments of the present disclosure have been shown and described, it will be understood by those skilled in the art that changes in form and detail may be made therein without departing from the scope of the invention as set forth in the appended claims. Such changes, modifications and alterations are intended to be encompassed within the scope of the present disclosure.
[0082] For example, in the above embodiment, the gasket 1 has a single third wide portion 13, but may have multiple third wide portions 13 as in Modification 1 shown in FIG. 11. A third narrow portion 16 is interposed between two adjacent third wide portions 13. The third narrow portion 16 has a third small diameter outer peripheral surface 16A and a third large diameter inner peripheral surface 16B. The third small diameter outer peripheral surface 16A has an outer peripheral groove. The third large diameter inner peripheral surface 16B has an inner peripheral groove. The outer peripheral groove of the third small diameter outer peripheral surface 16A has a substantially semicircular shape recessed toward the radial inside in a cross section including the central axis Ax of the gasket 1. The outer peripheral groove of the third small diameter outer peripheral surface 16A smoothly connects two adjacent third large diameter outer peripheral surfaces 13A. The inner circumferential groove of the third large diameter inner circumferential surface 16B has a substantially semicircular shape recessed radially outward in a cross section including the central axis Ax of the gasket 1. The inner circumferential groove of the third large diameter inner circumferential surface 16B smoothly connects the third small diameter inner circumferential surfaces 13B of two adjacent third wide portions 13.
[0083] 12, the first end face 11E may have a first protrusion 11F, and the second end face 12E may have a second protrusion 12F. This prevents the outer corner 11C from being pinched in the annular gap CL between the inner circumferential surface 3A of the hole of the outer member 3 and the large diameter portion 4A of the inner member 4 when the gasket 1 is slid along the central axis Ax against the inner circumferential surface 3A of the hole of the outer member 3 in a state where the gasket 1 is in contact with the outer circumferential surface 4C of the inner member 4. In addition, the first protrusion 11F and the second end face 12E are less likely to spread in a direction away from the vertical axis X of the cross section in a state where the gasket 1 is in contact with the outer circumferential surface 4C of the inner member 4. Therefore, deformation of the first protrusion 11F and the second end face 12E is suppressed, the surface pressure of the gasket 1 is maintained, and the sealing performance is improved. [Explanation of symbols]
[0084] A. Atmospheric space B Interior space Ax center axis line 1 Gasket 3,63 Outer member 4,64 Inner member 3A,63C Inner surface of hole 4C,64A Outer surface 11 First wide section 11A First large diameter outer periphery 11B first small diameter inner peripheral surface 11C,12C Outer corner 11D,12D Inner corner 11E First end face 11F First protrusion 12 Second wide section 12A Second large diameter outer periphery 12B Second small diameter inner surface 12E Second End Face 12F Second protrusion 13 Third wide section 13A Third large diameter outer periphery 13B Third small diameter inner surface 14 First narrow section 14A First small diameter outer periphery 14B First large diameter inner circumferential surface 14C First peripheral groove 14D First inner groove 15 Second narrow section 15A Second small diameter outer periphery 15B Second large diameter inner surface 15C Second peripheral groove 15D Second inner groove
Claims
1. An annular gasket made of elastomer that contacts the inner circumferential surface of the hole in the outer member and the outer circumferential surface of the inner member, separating the air space from the internal space of the outer member, The first wide section, A cylindrical first large-diameter outer surface that contacts the inner circumferential surface of the hole, A cylindrical first small-diameter inner surface that contacts the outer surface of the inner member, The first end face and, The first outer corner formed by the first large-diameter outer surface and the first end surface, The first inner corner formed by the first small-diameter inner circumferential surface and the first end face, A first wide section having, The second wide section, A cylindrical second large-diameter outer surface that contacts the inner circumferential surface of the hole, A cylindrical second small-diameter inner surface that contacts the outer surface of the inner member, The second end face and The second outer corner formed by the second large-diameter outer surface and the second end surface, The second inner corner formed by the second small-diameter inner circumferential surface and the second end face, A second wide section having, The third wide section, A third large-diameter outer surface that contacts the inner circumferential surface of the hole, A third small-diameter inner circumferential surface that contacts the outer circumferential surface of the inner member, A third wide section having, A first narrow portion interposed between the first wide portion and the third wide portion, A first small-diameter outer surface located away from the inner circumferential surface of the hole, the first small-diameter outer surface having a first outer groove, A first large-diameter inner surface of the inner member, located away from the outer surface, having a first inner groove, A first narrow section having, A second narrow portion interposed between the second wide portion and the third wide portion, A second small-diameter outer surface located away from the inner circumferential surface of the hole, the second small-diameter outer surface having a second outer groove, A second large-diameter inner surface of the inner member, located away from the outer surface, having a second inner groove, A second narrow section having, It has, The first end face has a first projection, The second end face has a second projection, gasket.
2. The gasket according to claim 1, wherein in a cross-section including the axis of the gasket, the radius of curvature of the first outer corner, the first inner corner, the second outer corner, and the second inner corner is 0.5 mm or less.
3. In the axial direction of the gasket, The first large-diameter outer surface contacts the inner surface of the hole for a length of 0.1 mm or more. The first small-diameter inner circumferential surface contacts the outer circumferential surface of the inner member for a length of 0.1 mm or more. The second large-diameter outer surface contacts the inner surface of the hole for a length of 0.1 mm or more. The second small-diameter inner circumferential surface contacts the outer circumferential surface of the inner member for a length of 0.1 mm or more. The gasket according to claim 1 or 2.
4. The third large-diameter outer surface has a 0.05 mm or more overlap with respect to the inner surface of the hole. The third small-diameter inner circumferential surface has a tolerance of 0.05 mm or more with respect to the outer circumferential surface of the inner member. The gasket according to claim 1 or 2.
5. When the gasket is compressed between the outer member and the inner member, the maximum distance between the first outer groove and the inner surface of the hole, the maximum distance between the second outer groove and the inner surface of the hole, the maximum distance between the first inner groove and the outer surface of the inner member, and the maximum distance between the second inner groove and the outer surface of the inner member are 0.05 mm or more. The gasket according to claim 1 or 2.
6. With respect to a plane perpendicular to the axis of the gasket, the gasket has a shape that is mirror-symmetrical. The gasket according to claim 1 or 2.
7. A gasket according to claim 1 or 2, The outer member and, The inner member and, A sealed structure having