sealing device

Abstract

To suppress a deformation of a rigid ring, and to reduce a rip of an elastic ring.SOLUTION: A sealing device comprises a cylinder part attached to a support member, and a circular plate part formed at one end so as to be arranged at an atmospheric side of the cylinder part. The circular plate part comprises: a first face arranged at the atmospheric side; a rigid ring formed of a rigid material having a second face located at a side opposite to the first face; an interposition cylinder part joined to the cylinder part of the rigid ring, and interposed between the cylinder part and the support member; and an elastic ring formed at one end so as to be arranged at the atmospheric side of the interposition cylinder part, and formed of an elastic layer joined to the first face of the circular plate part of the rigid ring. The first face of the circular ring has a plurality of protrusions protruding toward the atmospheric side. The elastic layer of the elastic ring is joined to the protrusions of the first face of the circular plate part and a portion other than the protrusions.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a sealing device.

Background Art

[0002] Patent Document 1 discloses a sealing device that is attached to a hole to close the hole. This sealing device has a metal ring and an elastic ring joined to the metal ring. The metal ring has a cylindrical portion fitted into the hole and a disc portion that extends radially inward from the cylindrical portion, and the elastic ring has an outer cylindrical portion joined to the outer peripheral surface of the cylindrical portion and fitted into the hole, and an elastic layer joined to the atmospheric side surface of the disc portion.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the sealing device described in Patent Document 1, the elastic layer joined to the atmospheric side surface of the disc portion prevents oxidation of the disc portion of the metal ring. In particular, when the sealing device is used in an environment with a large amount of water (salt water and muddy water), the elastic layer is effective. It is preferable that the elastic layer is surely formed over the entire necessary portion of the disc portion.

[0005] On the other hand, since the elastic layer always pulls the outer cylindrical portion of the elastic ring radially inward, there is a risk of deforming the rigid ring. If the rigid ring is deformed, there is a risk that the fluid inside the hole will leak.

[0006] Also, when the internal pressure of the hole in which the sealing device is mounted is high, a device for preventing the sealing device from coming out of the hole is required. However, when it is difficult to change the structure of the member having the hole, such a device is limited, and therefore, a measure is taken to increase the fitting allowance between the cylindrical portion of the metal ring and the inner peripheral surface of the hole in order to prevent the sealing device from coming out.

[0007] However, increasing this fit allowance raises concerns that when the sealing device is pressed into the hole, a large force will be applied to the outer cylindrical portion of the elastic ring, which is positioned around the cylindrical portion of the metal ring and fitted into the hole, potentially causing the outer cylindrical portion to tear. Furthermore, the elastic layer constantly pulls the outer cylindrical portion of the elastic ring radially inward, acting to separate the outer cylindrical portion from the cylindrical portion of the metal ring, increasing the risk of the outer cylindrical portion tearing when the sealing device is pressed into the hole and during use. If the outer cylindrical portion tears, there is a risk of fluid leakage from inside the hole.

[0008] Therefore, the present invention provides a sealing device that suppresses deformation of the rigid ring and reduces tearing of the elastic ring. [Means for solving the problem]

[0009] One aspect of the present invention provides a sealing device. This sealing device has a cylindrical portion attached to a support member and a disc portion formed at one end of the cylindrical portion so as to be positioned on the atmospheric side, wherein the disc portion comprises a rigid ring formed from a rigid material having a first surface positioned on the atmospheric side and a second surface opposite to the first surface, an intervening cylindrical portion joined to the cylindrical portion of the rigid ring and interposed between the cylindrical portion and the support member, and an elastic ring formed from an elastic material having an elastic layer formed at one end of the intervening cylindrical portion so as to be positioned on the atmospheric side and joined to the first surface of the disc portion of the rigid ring. The first surface of the disc portion of the rigid ring has a plurality of protrusions projecting toward the atmospheric side. The elastic layer of the elastic ring is joined to the protrusions and the portions other than the protrusions on the first surface of the disc portion.

[0010] In this embodiment, by providing multiple protrusions on the disc portion of the rigid ring, the elastic layer of the elastic ring joined to the disc portion bends around the protrusions, making it difficult for force to be transmitted within the elastic layer, and reducing the force with which the elastic layer of the elastic ring pulls the intervening cylindrical portion of the elastic ring in the radial direction. Therefore, deformation of the rigid ring is suppressed. In addition, since the force that attempts to separate the intervening cylindrical portion from the cylindrical portion of the metal ring (the force that pulls the intervening cylindrical portion in the radial direction) is reduced, the tearing of the intervening cylindrical portion of the elastic ring is reduced when attaching the sealing device to the support member and when using the sealing device. [Brief explanation of the drawing]

[0011] [Figure 1] This is a cross-sectional view showing a sealing device according to an embodiment of the present invention being pressed into a hole. [Figure 2] This is a cross-sectional view showing a sealing device in use according to an embodiment, which is press-fitted into a hole. [Figure 3] This is an enlarged cross-sectional view of a part of the sealing device according to the embodiment, in a state where it is not pressed into the hole. [Figure 4] This is a bottom view of Figure 3. [Figure 5] This is a cross-sectional view showing the state in which the elastic ring of the sealing device according to the embodiment is formed by a mold. [Figure 6] This is a cross-sectional view showing a sealing device according to a comparative example in use, which has been press-fitted into a hole. [Figure 7] This is an enlarged cross-sectional view of a part of a sealing device according to a modified embodiment, in a state where it is not pressed into the hole. [Figure 8] This is an enlarged cross-sectional view of a part of a sealing device according to another modification of the embodiment, in a state where it is not pressed into the hole. [Figure 9] This is a cross-sectional view showing a sealing device according to a modified example of an embodiment in use. [Figure 10] This is a cross-sectional view showing a sealing device according to another variation of the embodiment in use. [Modes for carrying out the invention]

[0012] Hereinafter, embodiments of the present invention will be described with reference to the attached drawings. The scale of the drawings is not necessarily accurate, and some features may be exaggerated or omitted.

[0013] FIG. 1 shows a sealing plug 1 which is a sealing device according to an embodiment of the present invention before use, and FIG. 2 shows the sealing plug 1 which is a sealing device during use. As shown in FIGS. 1 and 2, the sealing plug 1 is fixed to the housing 2 by being press-fitted into a hole 3 of the housing (supporting member) 2, and closes the hole 3. The housing 2 is formed of resin or metal, for example, an aluminum alloy.

[0014] The housing 2 is, for example, a housing of a motor of an electric vehicle, and the atmosphere side is an environment with a lot of water (salt water and muddy water), but the use of the present invention is not limited to this embodiment, and it may be a housing of other machines or structures.

[0015] As shown in FIG. 1, the hole 3 has a small-diameter portion 3a, a tapered portion 3b, a large-diameter portion 3c, and a tapered portion 3d. The small-diameter portion 3a, the tapered portion 3b, the large-diameter portion 3c, and the tapered portion 3d all have a circular cross-section and are concentric with each other. The small-diameter portion 3a is located at the inner side of the hole 3. The large-diameter portion 3c has an inner diameter larger than that of the small-diameter portion 3a, and the tapered portion 3b connects the small-diameter portion 3a and the large-diameter portion 3c. The tapered portion 3d is located on the atmosphere side and has a diameter that becomes smaller toward the inner side of the hole 3. However, the shape of the hole 3 is not limited to the illustration.

[0016] The sealing plug 1 has a rigid ring 6 and an elastic ring 8 joined to the rigid ring 6.

[0017] The rigid ring 6 is formed of a rigid material such as metal or resin. The rigid ring 6 is manufactured, for example, by forming a plate of cold-rolled steel sheet (SPCC) specified in JIS (Japanese Industrial Standards) G3141 by press working.

[0018] The rigid ring 6 has a cylindrical portion 6a, a disc portion 6b, and a connecting portion 6c. The cylindrical portion 6a is attached to the housing 2. Specifically, the cylindrical portion 6a is fitted into the hole 3 of the housing 2. The disc portion 6b is formed at one end so as to be disposed on the atmosphere side of the cylindrical portion 6a and extends radially inward of the cylindrical portion 6a. The disc portion 6b has a first surface 6b1 disposed on the atmosphere side and a second surface 6b2 disposed inside the cylindrical portion 6a. The connecting portion 6c connects the cylindrical portion 6a and the disc portion 6b and has a cross section curved in an arc shape.

[0019] The cylindrical portion 6a has a main cylindrical portion 6a1, an end portion 6a2, and an inclined portion 6a3. The main cylindrical portion 6a1, the end portion 6a2, and the inclined portion 6a3 all have a circular cross section and are concentric with each other. In the states shown in FIGS. 1 and 3 where the sealing plug 1 is not press-fitted into the hole 3, the main cylindrical portion 6a1 has a cylindrical shape. The end portion 6a2 is located on the side opposite to the disc portion 6b of the main cylindrical portion 6a1, and the outer peripheral surface of the end portion 6a2 is tapered. That is, the outer peripheral surface of the end portion 6a2 has a diameter that becomes smaller as it moves away from the main cylindrical portion 6a1. The inclined portion 6a3 is located on the disc portion 6b side of the main cylindrical portion 6a1 and has a frustum shape. Specifically, the inclined portion 6a3 is inclined so as to have a smaller diameter toward the disc portion 6b and thus toward the atmosphere side.

[0020] As shown in FIG. 2, the main cylindrical portion 6a1, the end portion 6a2, and the inclined portion 6a3 of the cylindrical portion 6a are all inserted into the hole 3. In this state, the end portion 6a2 is located in the small-diameter portion 3a of the hole 3, the main cylindrical portion 6a1 is located in the small-diameter portion 3a, the tapered portion 3b, and the large-diameter portion 3c of the hole 3, and the inclined portion 6a3 is located in the large-diameter portion 3c and the tapered portion 3d of the hole 3. The end portion 6a2 having a tapered outer peripheral surface facilitates the insertion of the cylindrical portion 6a into the hole 3. In the state of being fitted into the hole 3, the main cylindrical portion 6a1 receives a reaction force from the inner peripheral surface of the hole 3 and is deformed substantially along the contours of the small-diameter portion 3a, the tapered portion 3b, and the large-diameter portion 3c.

[0021] The elastic ring 8 is formed from an elastic material, such as an elastomer containing rubber. The available elastomers are not limited. However, as will be described later, according to this embodiment, tearing of the elastic ring 8 can be prevented or reduced. From this viewpoint, for example, an elastomer that is easily scratched, such as acrylic rubber, may be used as the material for the elastic ring 8.

[0022] The elastic ring 8 has an outer cylindrical portion (intervening cylindrical portion) 8a and an elastic layer 8b formed at the end of the outer cylindrical portion 8a so as to be positioned on the atmospheric side. The elastic layer 8b extends radially inward from the outer cylindrical portion 8a and is bonded to the entire first surface 6b1 of the disc portion 6b of the rigid ring 6.

[0023] The outer cylindrical portion 8a is joined to the outer circumferential surface of the inclined portion 6a3 of the cylindrical portion 6a of the rigid ring 6 and to the outer circumferential surface of the connecting portion 6c. The outer cylindrical portion 8a has an annular ridge portion 8a1 that protrudes radially outward. As shown in Figure 2, the ridge portion 8a1 is interposed between the outer circumferential surface of the cylindrical portion 6a of the rigid ring 6 and the inner circumferential surface of the hole 3. That is, the ridge portion 8a1 is fitted into the large diameter portion 3c and the tapered portion 3d of the hole 3, and is brought into close surface contact with the inner circumferential surface of the large diameter portion 3c and the inner circumferential surface of the tapered portion 3d, thereby closing the gap between the outer circumferential surface of the cylindrical portion 6a of the rigid ring 6 and the inner circumferential surface of the hole 3.

[0024] As shown in Figure 3, the outer surface of the raised portion 8a1 is tapered. That is, the outer surface of the raised portion 8a1 has a smaller diameter as it moves away from the elastic layer 8b. Therefore, the raised portion 8a1 is easily fitted into the large-diameter portion 3c of the hole 3.

[0025] As shown in Figures 1 to 3, the disc portion 6b of the rigid ring 6 has a plurality of protrusions 10 projecting toward the atmosphere on its first surface 6b1. The protrusions 10 are formed when the plate is press-formed into the rigid ring 6. Therefore, corresponding to the protrusions 10 formed on the first surface 6b1, recesses 12 are formed on the second surface 6b2 of the disc portion 6b. Since the recesses 12 are formed on the back of the protrusions 10 in this way, it is easy to form the protrusions 10 of the rigid ring 6 by press-forming.

[0026] Most of the projection 10 is flat and parallel to the rest of the disc portion 6b. As shown in Figure 3, the amount of projection 10 protruding from the rest of the disc portion 6b (depth of the recess 12) is small.

[0027] As shown in Figure 4, the multiple protrusions 10 and thus the recesses 12 are arranged equidistant from the central axis of the rigid ring 6. The first surface 6b1 has an intermediate portion 14 which is the part between the protrusions 10. Preferably, the protrusions 10 are arranged with equal angular spacing between them, but the angular spacing of the protrusions 10 does not necessarily have to be equal. In Figure 4, eight protrusions 10 and thus eight recesses 12 are shown, but the number of protrusions 10 and thus the number of recesses 12 is not limited to those shown. Also, the shapes of the protrusions 10 and recesses 12 are not limited to those shown.

[0028] As shown in Figures 1 to 3, the elastic layer 8b of the elastic ring 8 is joined to the projection 10 and the portion other than the projection 10 on the first surface 6b1 of the disc portion 6b of the rigid ring 6. The first surface 6b1 of the rigid ring 6 has the projection 10, but as shown in Figure 3, the surface 8b1 that is positioned on the atmospheric side of the elastic layer 8b of the elastic ring 8 is flat and parallel to the disc portion 6b. However, the surface 8b1 does not necessarily have to be flat.

[0029] By pressing the sealing plug 1 in the direction of arrow A in Figure 1, the sealing plug 1 is pressed into the hole 3 of the housing 2. At this time, a jig (not shown) can be used to press the elastic layer 8b of the elastic ring 8 in the direction of arrow A.

[0030] The elastic ring 8 of the sealing plug 1 according to this embodiment can be formed using the mold 15 shown in Figure 5. The mold 15 is made of a highly rigid metal and has a substantially cylindrical internal space 15a in which the rigid ring 6 is arranged. The main cylindrical portion 6a1 of the cylindrical portion 6a of the rigid ring 6 is fitted into the inner circumferential surface of the internal space 15a, and the inclined portion 6a3 of the cylindrical portion 6a abuts against the ridged portion 15b of the inner circumferential surface of the internal space 15a. This defines a cavity 16 for forming the elastic ring 8 between the internal space 15a and the rigid ring 6. The flat surface 16a of the cavity 16 facing the disc portion 6b is parallel to the disc portion 6b and forms the atmospheric side surface 8b1 of the elastic layer 8b of the elastic ring 8.

[0031] The elastic ring 8 is formed by placing the elastic material of the elastic ring 8 into the cavity 16 and curing it. At the same time, the elastic ring 8 is joined to the rigid ring 6. The method of forming the elastic ring 8 may be by pressing or injection molding. Before placing the elastic material of the elastic ring 8 into the cavity 16, it is preferable to apply an adhesive to the first surface 6b1, connecting portion 6c, and inclined portion 6a3 of the rigid ring 6 to improve the bonding between the elastic ring 8 and the rigid ring 6.

[0032] In this embodiment, as shown in Figure 3, the thickness t of the portion of the elastic layer 8b joined to the protrusion 10 is smaller than the thickness T of the portion of the elastic layer 8b joined to the portion of the first surface 6b1 other than the protrusion 10. Therefore, when the elastic ring 8 is joined to the rigid ring 6 by pressing or injection molding using the mold 15, a flow channel is formed between the protrusions 10 for the elastic material of the elastic ring 8 to flow. Specifically, the intermediate portion 14 between the protrusions 10 (see Figures 3 and 4) becomes the flow channel for the elastic material. In addition, elastic material is also placed between the protrusions 10 and the flat surface 16a of the mold 15, and the elastic material is strongly compressed between these, and the pressure is transmitted throughout the elastic material. Therefore, the flow of the elastic material is improved, variations in the thickness T of the elastic layer 8b of the completed elastic ring 8 (thickness of the portion joined to the portion of the first surface 6b1 other than the protrusion 10, see Figure 3) are suppressed, and the elastic material can be reliably distributed throughout the entire first surface 6b1.

[0033] Furthermore, as shown in Figure 3, by providing multiple protrusions 10 on the disc portion 6b of the rigid ring 6, the elastic layer 8b joined to the disc portion 6b bends around the protrusions 10, making it difficult for force to be transmitted within the elastic layer 8b, and reducing the force with which the elastic layer 8b of the elastic ring 8 pulls the outer cylindrical portion 8a of the elastic ring 8 in the radial direction. In particular, in this embodiment, the thickness t of the portion of the elastic layer 8b of the elastic ring 8 joined to the protrusions 10 is smaller than the thickness T of the portion of the elastic layer 8b joined to the portion of the first surface 6b1 other than the protrusions 10, so the force with which the elastic layer 8b pulls the outer cylindrical portion 8a of the elastic ring 8 radially inward is significantly reduced. Since the atmospheric side surface 8b1 of the elastic layer 8b of the elastic ring 8 is flat, the thickness t of the portion of the elastic layer 8b of the elastic ring 8 joined to the protrusions 10 is reliably smaller than the thickness T of the portion of the elastic layer 8b joined to the portion of the first surface 6b1 other than the protrusions 10.

[0034] In this way, the force exerted by the elastic layer 8b pulling the outer cylindrical portion 8a of the elastic ring 8 radially inward is reduced, thus suppressing deformation of the rigid ring 6 when the sealing plug 1 is pressed into the hole 3 and when the sealing plug 1 is in use.

[0035] Furthermore, since the force that attempts to separate the outer cylindrical portion 8a from the cylindrical portion 6a of the metal ring (the force pulling the outer cylindrical portion 8a radially inward) is reduced, the tearing of the outer cylindrical portion 8a of the elastic ring 8 is reduced when the sealing plug 1 is pressed into the hole 3 and when the sealing plug 1 is in use.

[0036] Figure 6 shows a comparative example of a seal plug 1A pressed into hole 2. In the seal plug 1A, the projection 10 is not provided on the disc portion 6b of the rigid ring 6. Since there is no projection 10 to improve the flow of elastic material when forming the elastic ring 8, the thickness of the elastic layer 8b in the comparative example must be larger than that in the embodiment in order to form the elastic layer 8b of the elastic ring 8 over the entire first surface 6b1 of the disc portion 6b of the rigid ring 6. Also, because the elastic layer 8b is flat and does not bend, force is easily transmitted within the elastic layer 8b. Therefore, compared to the embodiment, the force exerted by the elastic layer 8b pulling the outer cylindrical portion 8a of the elastic ring 8 radially inward is greater, and as a result, there is a risk that the rigid ring 6 will bend as shown in Figure 6. Bending of the rigid ring 6 can occur both when pressing the seal plug 1A into hole 3 and when using the seal plug 1. If the rigid ring 6 is bent, there is a risk that the fluid inside hole 3 will leak.

[0037] Furthermore, the large force exerted by the elastic layer 8b pulling the outer cylindrical portion 8a of the elastic ring 8 radially inward acts to separate the outer cylindrical portion 8a from the cylindrical portion 6a of the metal ring. There is a concern that the outer cylindrical portion 8a of the elastic ring 8 may be torn off when the seal plug 1A is pressed into the hole 3 and when the seal plug 1 is used. Figure 6 shows an example where the ridged portion 8a1 of the outer cylindrical portion 8a is torn into a jagged shape. If the outer cylindrical portion 8a is torn off, there is a risk that the fluid inside the hole 3 may leak.

[0038] According to this embodiment, the problems described with reference to Figure 6 are resolved, and the sealing performance of the sealing plug 1 can be maintained over a long period of time.

[0039] In this embodiment, the thickness t (see Figure 3) of the portion of the elastic layer 8b of the elastic ring 8 joined to the projection 10 is preferably 0.1 mm or more and less than 0.5 mm. When the thickness t is 0.1 mm or more, when the sealing plug 1 is pressed into the hole 3, for example, even if the portion of the elastic layer 8b joined to the projection 10 is pressed with a jig, there is little risk of damage to the elastic layer 8b. Also, when the thickness t is 0.1 mm or more, even if the portion of the elastic layer 8b joined to the projection 10 is slightly damaged when the sealing plug 1 is pressed into the hole 3 and during use of the sealing plug 1, there is little risk of the first surface 6b1 of the rigid ring 6 being exposed, and oxidation of the first surface 6b1 is suppressed.

[0040] If the thickness t is 0.5 mm or more, the elastic layer 8b exerts a strong force pulling the outer cylindrical portion 8a of the elastic ring 8 radially inward, making the rigid ring 6 prone to deformation. This may cause the outer cylindrical portion 8a of the elastic ring 8 to tear when the sealing plug 1 is pressed into the hole 3 and when the sealing plug 1 is in use.

[0041] However, the required thickness of the elastic ring 8 varies depending on the elastic material of the elastic ring 8, the composition of the adhesive described above, and / or the manufacturing method of the elastic ring 8; therefore, the thickness t is not limited to 0.1 mm or more and less than 0.5 mm.

[0042] While not absolutely necessary, preferably, as shown in Figures 3 and 4, the distance D between the projection 10 of the rigid ring 6 and the center of the disc portion 6b of the rigid ring 6 is greater than half the radius R of the disc portion 6b. In other words, since the projection 10 of the rigid ring 6 is located near the outer edge of the disc portion 6b, the portion of the elastic layer 8b of the elastic ring 8 that is joined to the projection 10 is located near the outer edge of the elastic layer 8b. Therefore, compared to the case where the portion of the elastic layer 8b that is located radially inward, the force exerted by the elastic layer 8b of the elastic ring 8 on the outer cylindrical portion 8a of the elastic ring 8 is reduced.

[0043] In the above embodiment, the thickness t of the portion of the elastic layer 8b joined to the projection 10 is smaller than the thickness T of the portion of the elastic layer 8b joined to the portion of the first surface 6b1 other than the projection 10. However, as shown in Figures 7 and 8, it is not necessarily the case that it is as in the above embodiment. Figures 7 and 8 are enlarged cross-sectional views of a part of the sealing plug 1 according to a modified embodiment in a state where it is not press-fitted into the hole, respectively.

[0044] In the modified example shown in Figure 7, the thickness t of the portion of the elastic layer 8b joined to the projection 10 is equal to the thickness T of the portion of the elastic layer 8b joined to the portion of the first surface 6b1 other than the projection 10. In other words, the thickness of the elastic layer 8b is uniform, and the elastic layer 8b has a shape that conforms to the shape of the projection 10 and the portion other than the projection 10. In the modified example shown in Figure 8, the thickness t of the portion of the elastic layer 8b joined to the projection 10 is greater than the thickness T of the portion of the elastic layer 8b joined to the portion of the first surface 6b1 other than the projection 10.

[0045] In the modified examples shown in Figures 7 and 8, the elastic layer 8b joined to the disc portion 6b bends around the projection 10, making it difficult for force to be transmitted within the elastic layer 8b, and reducing the force with which the elastic layer 8b of the elastic ring 8 pulls radially on the outer cylindrical portion 8a of the elastic ring 8. Therefore, when the sealing plug 1 is pressed into the hole 3 and when the sealing plug 1 is used, deformation of the rigid ring 6 is suppressed, and tearing of the outer cylindrical portion 8a of the elastic ring 8 is reduced.

[0046] Figure 9 shows an oil seal 21, which is a sealing device according to a modified embodiment in use. The oil seal 21 is fixed to the housing (support member) 22 by being press-fitted into a hole 23 in the housing 22, which is made of resin or metal. A shaft 25 is positioned inside the hole 23. The shaft 25 may be a rotary shaft that rotates around its axis, or a reciprocating shaft that moves back and forth along its axial direction.

[0047] The oil seal 21 has a rigid ring 26 and an elastic ring 28 joined to the rigid ring 26.

[0048] The rigid ring 26 is formed from a rigid material such as metal or resin. The rigid ring 26 has a cylindrical portion 26a and a disc portion 26b. The cylindrical portion 26a is attached to the housing 22. Specifically, the cylindrical portion 26a is inserted into a hole 23 in the housing 22. The disc portion 26b is formed at one end of the cylindrical portion 26a so as to be positioned on the atmospheric side and extends radially inward from the cylindrical portion 26a. The disc portion 26b has an annular shape. The disc portion 26b has a first surface 26b1 positioned on the atmospheric side and a second surface 26b2 positioned on the inside of the cylindrical portion 26a.

[0049] The elastic ring 28 is formed from an elastic material, such as an elastomer containing rubber. The available elastomers are not limited. However, this modification can prevent or reduce tearing of the elastic ring 28. From this viewpoint, a material that is easily scratched, such as acrylic rubber, may be used for the elastic ring 28.

[0050] The elastic ring 28 has an outer cylindrical portion (intervening cylindrical portion) 28a and an elastic layer 28b formed at the end of the outer cylindrical portion 28a so as to be positioned on the atmospheric side. The elastic layer 28b extends radially inward from the outer cylindrical portion 28a and is bonded to the entire first surface 26b1 of the disc portion 26b of the rigid ring 26.

[0051] The elastic layer 28b has an annular shape. The elastic ring 28 has a seal lip 29 and a dust lip 30 positioned radially inward of the elastic layer 28b. A garter spring 31 is wound around the seal lip 29 to press it radially inward. However, the garter spring 31 is not absolutely necessary, nor is the dust lip 30 absolutely necessary.

[0052] The outer cylindrical portion 28a is joined to the outer circumferential surface of the cylindrical portion 26a of the rigid ring 26. The outer cylindrical portion 28a is interposed between the outer circumferential surface of the cylindrical portion 26a of the rigid ring 26 and the inner circumferential surface of the hole 23. That is, the outer cylindrical portion 28a is fitted into the hole 23 and made to be in close surface contact with the inner circumferential surface of the hole 23, thereby closing the gap between the outer circumferential surface of the cylindrical portion 26a of the rigid ring 26 and the inner circumferential surface of the hole 23.

[0053] The disc portion 26b of the rigid ring 26 has a plurality of protrusions 32 projecting toward the atmosphere on its first surface 26b1. The protrusions 32 are formed when the plate is press-formed into the rigid ring 26. Therefore, corresponding to the protrusions 32 formed on the first surface 26b1, recesses 34 are formed on the second surface 26b2 of the disc portion 26b. Since the recesses 34 are formed on the back of the protrusions 32 in this way, it is easy to form the protrusions 32 of the rigid ring 26 by press-forming. Most of the protrusions 32 are flat and parallel to the parts of the disc portion 26b other than the protrusions 32. The amount of protrusion P (depth of the recesses 34) of the protrusions 32 relative to the parts of the disc portion 26b other than the protrusions 32 is small.

[0054] Although not shown in the figures, the multiple protrusions 32 and thus the recesses 34 are arranged at equidistant distances from the central axis of the rigid ring 26. Preferably, the protrusions 32 are arranged with equal angular spacing between them, but the angular spacing of the protrusions 32 does not necessarily have to be equal.

[0055] The elastic layer 28b of the elastic ring 28 is joined to the projection 32 and the portion other than the projection 32 on the first surface 26b1 of the disc portion 26b of the rigid ring 26. The first surface 26b1 of the rigid ring 26 has the projection 32, but the surface 28b1 of the elastic ring 28 that is positioned on the atmospheric side of the elastic layer 28b is flat and parallel to the disc portion 26b. However, the surface 28b1 does not necessarily have to be flat.

[0056] The elastic ring 28 of the oil seal 21 can also be joined to the rigid ring 26 by pressing or injection molding using a mold. For the same reasons explained with reference to Figure 5, by providing multiple protrusions 32 on the disc portion 26b of the rigid ring 26, the flow of the elastic material is improved, variations in the thickness of the elastic layer 28b of the completed elastic ring 28 (the thickness of the portion joined to the part of the first surface 26b1 other than the protrusions 32) are suppressed, and the elastic material can be reliably distributed throughout the entire first surface 26b1.

[0057] Furthermore, the elastic layer 28b joined to the disc portion 26b bends around the projection 32, making it difficult for force to be transmitted within the elastic layer 28b, and reducing the force with which the elastic layer 28b of the elastic ring 28 pulls the outer cylindrical portion 28a of the elastic ring 28 in the radial direction. In particular, in this oil seal 21, the thickness of the portion of the elastic layer 28b of the elastic ring 28 joined to the projection 32 is smaller than the thickness of the portion of the elastic layer 28b joined to the portion of the first surface 26b1 other than the projection 32, so the force with which the elastic layer 28b pulls the outer cylindrical portion 28a of the elastic ring 28 radially inward is significantly reduced. Since the atmospheric side surface 28b1 of the elastic layer 28b of the elastic ring 28 is flat, the thickness of the portion of the elastic layer 28b of the elastic ring 28 joined to the projection 32 is reliably smaller than the thickness of the portion of the elastic layer 28b joined to the portion of the first surface 26b1 other than the projection 32. However, the modified examples shown in Figures 7 and 8 may also be applied to this oil seal 21.

[0058] In this way, the force exerted by the elastic layer 28b on the outer cylindrical portion 28a of the elastic ring 28 in the radial direction is reduced, thus suppressing deformation of the rigid ring 26 when the oil seal 21 is pressed into the hole 23 and when the oil seal 21 is in use. Therefore, it is possible to maintain the sealing performance of the oil seal 21 over a long period of time.

[0059] Furthermore, since the force that attempts to separate the outer cylindrical portion 28a from the cylindrical portion 26a of the metal ring (the force pulling the outer cylindrical portion 28a radially inward) is reduced, the tearing of the outer cylindrical portion 28a of the elastic ring 28 is reduced when the oil seal 21 is pressed into the hole 23 and when the oil seal 21 is in use. Therefore, it is possible to maintain the sealing performance of the oil seal 21 over a long period of time.

[0060] While not absolutely necessary, preferably, the distance D1 between the projection 32 of the rigid ring 26 and the outer edge of the disc portion 26b of the rigid ring 26 is smaller than the distance D2 between the projection 32 and the inner edge of the disc portion 26b. In other words, since the projection 32 of the rigid ring 26 is located near the outer edge of the disc portion 26b, the portion of the elastic layer 28b of the elastic ring 28 that is joined to the projection 32 is located near the outer edge of the elastic layer 28b. Therefore, compared to the case where the portion of the elastic layer 28b that is located radially inward, the force exerted by the elastic layer 28b of the elastic ring 28 pulling the outer cylindrical portion 28a of the elastic ring 28 radially inward is reduced.

[0061] Figure 10 shows a hub bearing seal 31, which is a sealing device relating to another modification of an embodiment in use. The hub bearing seal 31 is positioned in the gap between the outer ring 32 and the inner ring 33 of the hub bearing. The hub bearing seal 31 comprises an outer sealing member 40 and an inner sealing member 50. The outer sealing member 40 and the inner sealing member 50 are annular, but in Figure 10 only their left portions are shown. In Figure 10, the outer ring 32 and the inner ring 33 are shown by dashed lines, and the outer sealing member 40 and the inner sealing member 50 are shown in an uncompressed state between the outer ring 32 and the inner ring 33.

[0062] The outer sealing member 40 is a fixed sealing member that is attached to the outer ring 32 and does not rotate. The outer sealing member 40 has a composite structure comprising an elastic ring 41 and a rigid ring 42.

[0063] The elastic ring 41 is formed of an elastic material, such as an elastomer. The elastic ring 41 has lips 43, 44, and 45.

[0064] The rigid ring 42 is made of a rigid material, such as metal, and reinforces the elastic ring 41. The rigid ring 42 has a substantially L-shaped cross-section. The rigid ring 42 is press-fitted into a hole in the outer ring 32 and fixed in place. A portion of the rigid ring 42 is embedded in the elastic ring 41 and is in close contact with the elastic ring 41.

[0065] The inner sealing member 50 can also be called a slinger, or rotating sealing member. The inner sealing member 50 is attached to the inner ring 33, and when the inner ring 33 rotates, the inner sealing member 50 rotates together with the inner ring 33, splashing away foreign matter (such as water) coming from the outside.

[0066] The inner sealing member (sealing device) 50 is also a composite structure having a rigid ring 51 and an elastic ring 52 joined to the rigid ring 51. The rigid ring 51 is formed from a rigid material such as metal or resin.

[0067] The rigid ring 51 has a substantially L-shaped cross-section. Specifically, the rigid ring 51 comprises a cylindrical sleeve (cylindrical portion) 51a and a flange (disc portion) 51b. The sleeve 51a is attached to the inner ring 33. Specifically, the inner ring (support member) 33 is fitted into the sleeve 51a by a press-fit method. The flange 51b is formed at one end of the sleeve 51a so as to be positioned on the atmospheric side and extends radially outward from the sleeve 51a. The flange 51b has an annular shape. The flange 51b has a first surface 51b1 positioned on the atmospheric side and a second surface 51b2 positioned on the outside of the sleeve 51a.

[0068] Lip 43 of the outer sealing member 40 is a radial lip (grease lip) extending radially inward. Lip 44 is a radial lip (dust lip) extending radially inward. Lips 43 and 44 extend toward the sleeve 51a of the inner sealing member 50, and the tips of lips 43 and 44 slidably contact the outer circumferential surface of the sleeve 51a. Lip 45 is an axial lip (side lip) extending laterally. Lip 45 extends radially outward and toward the atmosphere, and slidably contacts the second surface 51b2 of the flange 51b of the rigid ring 51 of the second sealing member 50.

[0069] The elastic ring 52 is formed from an elastic material, such as an elastomer containing rubber. The available elastomers are not limited. However, this modification can prevent or reduce tearing of the elastic ring 52. From this viewpoint, a material that is easily scratched, such as acrylic rubber, may be used for the elastic ring 52.

[0070] The elastic ring 52 has an inner cylindrical portion (intervening cylindrical portion) 52a and an elastic layer 52b formed at the end of the inner cylindrical portion 52a that is positioned on the atmospheric side. The elastic layer 52b extends radially outward from the inner cylindrical portion 52a and is bonded to the entire first surface 51b1 of the flange 51b of the rigid ring 51. The elastic layer 52b has an annular shape.

[0071] The inner cylindrical portion 52a is joined to the inner circumferential surface of the sleeve 51a of the rigid ring 51. The inner cylindrical portion 52a is interposed between the inner circumferential surface of the sleeve 51a of the rigid ring 51 and the outer circumferential surface of the inner ring 33. That is, the inner cylindrical portion 52a is in close surface contact with the outer circumferential surface of the inner ring 33, closing the gap between the inner circumferential surface of the sleeve 51a of the rigid ring 51 and the outer circumferential surface of the inner ring 33.

[0072] The flange 51b of the rigid ring 51 has a plurality of protrusions 53 projecting toward the atmosphere on its first surface 51b1. The protrusions 53 are formed when the plate is press-formed into the rigid ring 51. Therefore, corresponding to the protrusions 53 formed on the first surface 51b1, recesses 54 are formed on the second surface 51b2 of the flange 51b. Because the recesses 54 are formed on the back of the protrusions 53 in this way, it is easy to form the protrusions 53 of the rigid ring 51 by press-forming. Most of the protrusions 53 are flat and parallel to the parts of the flange 51b other than the protrusions 53. The amount of protrusion P (depth of the recesses 54) of the protrusions 53 relative to the parts of the flange 51b other than the protrusions 53 is small.

[0073] Although not shown in the figures, the multiple protrusions 53 and thus the recesses 54 are arranged at equidistant distances from the central axis of the rigid ring 51. Preferably, the protrusions 53 are arranged with equal angular spacing between them, but the angular spacing of the protrusions 53 does not necessarily have to be equal.

[0074] The elastic layer 52b of the elastic ring 52 is joined to the projection 53 and the portion of the flange 51b of the rigid ring 51 that is not the projection 53 on the first surface 51b1. The first surface 51b1 of the rigid ring 51 has the projection 53, but the surface 52b1 of the elastic ring 52 that is positioned on the atmospheric side is flat and parallel to the flange 51b. However, the surface 52b1 does not necessarily have to be flat.

[0075] The elastic ring 52 of the inner sealing member 50 can also be joined to the rigid ring 51 by pressing or injection molding using a mold. For the same reasons explained with reference to Figure 5, by providing multiple protrusions 53 on the flange 51b of the rigid ring 51, the flow of the elastic material is improved, variations in the thickness of the elastic layer 52b of the completed elastic ring 52 (the thickness of the portion joined to the part of the first surface 51b1 other than the protrusions 53) are suppressed, and the elastic material can be reliably distributed throughout the entire first surface 51b1.

[0076] Furthermore, the elastic layer 52b joined to the flange 51b bends around the projection 53, making it difficult for force to be transmitted within the elastic layer 52b, and reducing the force with which the elastic layer 52b of the elastic ring 52 pulls the inner cylindrical portion 52a of the elastic ring 52 in the radial direction. In particular, in this inner sealing member 50, the thickness of the portion of the elastic layer 52b of the elastic ring 52 joined to the projection 53 is smaller than the thickness of the portion of the elastic layer 52b joined to the portion of the first surface 51b1 other than the projection 53, so the force with which the elastic layer 52b pulls the inner cylindrical portion 52a of the elastic ring 52 radially outward is significantly reduced. Since the atmospheric side surface 52b1 of the elastic layer 52b of the elastic ring 52 is flat, the thickness of the portion of the elastic layer 52b of the elastic ring 52 joined to the projection 53 is reliably smaller than the thickness of the portion of the elastic layer 52b joined to the portion of the first surface 51b1 other than the projection 53. However, the modified examples shown in Figures 7 and 8 may also be applied to this inner sealing member 50.

[0077] In this way, the force exerted by the elastic layer 52b on the inner cylindrical portion 52a of the elastic ring 52 in the radially outward direction is reduced, thus suppressing deformation of the rigid ring 51 when the inner sealing member 50 is attached to the inner ring 33 and when the inner sealing member 50 is in use. Therefore, it is possible to maintain the sealing performance of the inner sealing member 50 over a long period of time.

[0078] Furthermore, since the force that attempts to peel the inner cylindrical portion 52a from the sleeve 51a of the metal ring (the force pulling the inner cylindrical portion 52a radially outward) is reduced, the tearing of the inner cylindrical portion 52a of the elastic ring 52 is reduced when attaching the inner sealing member 50 to the inner ring 33 and when using the inner sealing member 50. Therefore, it is possible to maintain the sealing performance of the inner sealing member 50 over a long period of time.

[0079] While not absolutely necessary, preferably, the distance D3 between the projection 53 of the rigid ring 51 and the outer edge of the flange 51b of the rigid ring 51 is greater than the distance D4 between the projection 53 and the inner edge of the flange 51b. In other words, since the projection 53 of the rigid ring 51 is located near the inner edge of the flange 51b, the portion of the elastic layer 52b of the elastic ring 52 that is joined to the projection 53 is located near the inner edge of the elastic layer 52b. Therefore, compared to the case where the portion of the elastic layer 52b that is located radially outward is reduced, the force exerted by the elastic layer 52b of the elastic ring 52 on the inner cylindrical portion 52a of the elastic ring 52 is reduced.

[0080] Although the present invention has been illustrated and described above with reference to preferred embodiments, those skilled in the art will understand that modifications to form and detail are possible without departing from the scope of the invention as described in the claims. Such modifications, alterations, and changes should be included within the scope of the present invention.

[0081] Aspects of the present invention are also described in the numbered clauses below. Clause 1. A rigid ring formed from a rigid material having a cylindrical portion attached to a support member and a disc portion formed at one end of the cylindrical portion so as to be positioned on the atmospheric side, wherein the disc portion has a first surface positioned on the atmospheric side and a second surface opposite to the first surface, The elastic ring is made of an elastic material and comprises an intervening cylindrical portion which is joined to the cylindrical portion of the rigid ring and interposed between the cylindrical portion and the support member, and an elastic layer which is formed at one end of the intervening cylindrical portion which is positioned on the atmospheric side and joined to the first surface of the disc portion of the rigid ring. The first surface of the disc portion of the rigid ring has a plurality of protrusions projecting toward the atmosphere, The elastic layer of the elastic ring is joined to the protrusions on the first surface of the disc portion and to the portion other than the protrusions. Sealing device.

[0082] Clause 2. The thickness of the portion of the elastic layer joined to the projection on the first surface of the disc is less than the thickness of the portion of the elastic layer joined to the portion of the first surface other than the projection. The sealing device described in Clause 1. According to this clause, when joining an elastic ring to a rigid ring using a mold by press or injection molding, a channel is formed between the protrusions for the elastic material of the elastic ring to flow through, and elastic material is also placed between the protrusions and the mold. Between these, the elastic material is strongly compressed, and the pressure is transmitted throughout the elastic material. Therefore, the flow of the elastic material is improved, variations in the thickness of the elastic layer of the finished elastic ring are suppressed, and the elastic material can be reliably distributed throughout the entire first surface. In addition, the force with which the elastic layer pulls the outer cylindrical portion of the elastic ring radially inward is significantly reduced.

[0083] Clause 3. The surface of the elastic ring that is positioned on the atmospheric side of the elastic layer is flat. The sealing device described in Clause 1. According to this clause, the thickness of the portion of the elastic ring joined to the projection of the elastic layer is reliably smaller than the thickness of the portion of the elastic layer joined to the portion of the first surface other than the projection. As a result, the force with which the elastic layer of the elastic ring pulls radially on the intervening cylindrical portion of the elastic ring is significantly reduced, deformation of the rigid ring is suppressed, and tearing of the elastic ring is reduced when it is press-fitted into the hole. In addition, it is easy to join the elastic ring to the rigid ring using a mold by pressing or injection molding.

[0084] Clause 4. The thickness of the portion of the elastic layer joined to the projection on the first surface of the disc portion is equal to or greater than the thickness of the portion of the elastic layer joined to the portion of the first surface other than the projection. The sealing device described in Clause 1.

[0085] Clause 5. The second surface of the disc portion of the rigid ring has a recess on the back side of the projection. A sealing device as described in any one of clauses 1 to 4. According to this clause, the protrusions of the rigid ring can be easily formed by press working.

[0086] Clause 6. The sealing device is a sealing plug that closes the hole in the support member, The cylindrical portion of the rigid ring is fitted into the hole. The disc portion of the rigid ring is positioned radially inward of the cylindrical portion. The interposed cylindrical portion of the elastic ring is joined to the outer circumferential surface of the cylindrical portion and interposed between the outer circumferential surface of the cylindrical portion and the inner circumferential surface of the hole. The elastic layer of the elastic ring is arranged radially inward of the intervening cylindrical portion. The distance between the projection of the rigid ring and the center of the disc portion is greater than half the radius of the disc portion. A sealing device as described in any one of clauses 1 to 5. According to this clause, the projection of the rigid ring is positioned near the outer edge of the disc portion, so the thinner portion of the elastic ring joined to the projection of the elastic layer is positioned near the outer edge of the elastic layer. Therefore, compared to the case where the thinner portion of the elastic layer is positioned radially inward, the force exerted by the elastic layer of the elastic ring on the intervening cylindrical portion of the elastic ring radially inward is reduced.

[0087] Clause 7. The sealing device is an oil seal positioned in the hole of the support member, The cylindrical portion of the rigid ring is designed to be inserted into the hole. The disc portion of the rigid ring has an annular shape and is positioned radially inward of the cylindrical portion. The interposed cylindrical portion of the elastic ring is joined to the outer circumferential surface of the cylindrical portion and interposed between the outer circumferential surface of the cylindrical portion and the inner circumferential surface of the hole. The elastic layer of the elastic ring has an annular shape and is arranged radially inward of the intervening cylindrical portion. The elastic ring further comprises at least one lip that is slidably in contact with a shaft disposed inside the hole, the lip being positioned radially inward of the elastic layer, The distance between the projection of the rigid ring and the outer edge of the disc portion is smaller than the distance between the projection and the inner edge of the disc portion. A sealing device as described in any one of clauses 1 to 5. According to this clause, the projection of the rigid ring is positioned near the outer edge of the disc portion, so the thinner portion of the elastic ring joined to the projection of the elastic layer is positioned near the outer edge of the elastic layer. Therefore, compared to the case where the thinner portion of the elastic layer is positioned radially inward, the force exerted by the elastic layer of the elastic ring on the intervening cylindrical portion of the elastic ring radially inward is reduced.

[0088] Clause 8. The sealing device is a sealing member positioned outside the support member, The support member is fitted into the cylindrical portion of the rigid ring. The disc portion of the rigid ring has an annular shape and is positioned radially outward from the cylindrical portion. The interposed cylindrical portion of the elastic ring is joined to the inner circumferential surface of the cylindrical portion and interposed between the inner circumferential surface of the cylindrical portion and the outer circumferential surface of the support member. The elastic layer of the elastic ring has an annular shape and is arranged radially outward of the intervening cylindrical portion. The distance between the projection of the rigid ring and the outer edge of the disc portion is greater than the distance between the projection and the inner edge of the disc portion. A sealing device as described in any one of clauses 1 to 5. According to this clause, the projection of the rigid ring is positioned near the inner edge of the disc portion, so the thinner portion of the elastic ring joined to the projection of the elastic layer is positioned near the inner edge of the elastic layer. Therefore, compared to the case where the thinner portion of the elastic layer is positioned radially outward of the elastic layer, the force exerted by the elastic layer of the elastic ring on the intervening cylindrical portion of the elastic ring radially outward is reduced. [Explanation of Symbols]

[0089] 1. Sealing stopper (sealing device) 2 Housing (support member) 3 holes 6 Rigid ring 8 Elastic ring 6a Cylindrical section 6b Disc section 6b1 First face 6b2 Second face 6c connector 8 Elastic ring 8a Outer cylindrical portion (interposed cylindrical portion) 8b Elastic layer 10 protrusions 12 recesses 21. Oil seal (sealing device) 22 Housing (support member) 23 holes 26 Rigid ring 26a Cylindrical section 26b Disc section 26b1 First face 26b2 Second face 28 Elastic ring 28a Outer cylindrical part (interposed cylindrical part) 28b Elastic layer 28b1 Atmospheric side 32 Protrusion 34 recess 33 Inner ring (support member) 50. Inner sealing member (sealing device) 51 Rigid ring 51a Sleeve (cylindrical part) 51b Flange (disc section) 51b1 First side 51b2 Second side 52 Elastic ring 52a Inner cylindrical portion (interposed cylindrical portion) 52b Elastic layer 53 Protrusion 54 recess

Claims

1. It has a cylindrical portion attached to a support member, and a disc portion formed at one end of the cylindrical portion so as to be positioned on the atmospheric side, wherein the disc portion is a rigid ring formed from a rigid material having a first surface positioned on the atmospheric side and a second surface opposite to the first surface, The elastic ring is made of an elastic material and comprises an intervening cylindrical portion which is joined to the cylindrical portion of the rigid ring and interposed between the cylindrical portion and the support member, and an elastic layer which is formed at one end of the intervening cylindrical portion which is positioned on the atmospheric side and joined to the first surface of the disc portion of the rigid ring. The first surface of the disc portion of the rigid ring has a plurality of protrusions projecting toward the atmosphere, The elastic layer of the elastic ring is joined to the protrusions on the first surface of the disc portion and to the portion other than the protrusions. The thickness of the portion of the elastic layer joined to the projection on the first surface of the disc portion is equal to or greater than the thickness of the portion of the elastic layer joined to the portion of the first surface other than the projection. Sealing device.

2. A rigid ring formed from a rigid material having a cylindrical portion attached to a support member and a disc portion formed at one end of the cylindrical portion so as to be positioned on the atmospheric side, wherein the disc portion has a first surface positioned on the atmospheric side and a second surface opposite to the first surface, The elastic ring is made of an elastic material and comprises an intervening cylindrical portion which is joined to the cylindrical portion of the rigid ring and interposed between the cylindrical portion and the support member, and an elastic layer which is formed at one end of the intervening cylindrical portion which is positioned on the atmospheric side and joined to the first surface of the disc portion of the rigid ring. A sealing device for closing the hole in the support member, The first surface of the disc portion of the rigid ring has a plurality of protrusions projecting toward the atmosphere, The elastic layer of the elastic ring is joined to the protrusions on the first surface of the disc portion and to the portion other than the protrusions. The cylindrical portion of the rigid ring is fitted into the hole. The disc portion of the rigid ring is positioned radially inward of the cylindrical portion. The interposed cylindrical portion of the elastic ring is joined to the outer circumferential surface of the cylindrical portion and interposed between the outer circumferential surface of the cylindrical portion and the inner circumferential surface of the hole. The elastic layer of the elastic ring is arranged radially inward of the intervening cylindrical portion. The distance between the projection of the rigid ring and the center of the disc portion is greater than half the radius of the disc portion. Sealing device.

3. A rigid ring formed from a rigid material having a cylindrical portion attached to a support member and a disc portion formed at one end of the cylindrical portion so as to be positioned on the atmospheric side, wherein the disc portion has a first surface positioned on the atmospheric side and a second surface opposite to the first surface, The elastic ring is made of an elastic material and comprises an intervening cylindrical portion which is joined to the cylindrical portion of the rigid ring and interposed between the cylindrical portion and the support member, and an elastic layer which is formed at one end of the intervening cylindrical portion which is positioned on the atmospheric side and joined to the first surface of the disc portion of the rigid ring. A sealing device disposed in the hole of the support member, The first surface of the disc portion of the rigid ring has a plurality of protrusions projecting toward the atmosphere, The elastic layer of the elastic ring is joined to the protrusions on the first surface of the disc portion and to the portion other than the protrusions. The cylindrical portion of the rigid ring is designed to be inserted into the hole. The disc portion of the rigid ring has an annular shape and is positioned radially inward of the cylindrical portion. The interposed cylindrical portion of the elastic ring is joined to the outer circumferential surface of the cylindrical portion and interposed between the outer circumferential surface of the cylindrical portion and the inner circumferential surface of the hole. The elastic layer of the elastic ring has an annular shape and is arranged radially inward of the intervening cylindrical portion. The elastic ring further comprises at least one lip that is slidably in contact with a shaft disposed inside the hole, the lip being positioned radially inward of the elastic layer, The distance between the projection of the rigid ring and the outer edge of the disc portion is smaller than the distance between the projection and the inner edge of the disc portion. Sealing device.

4. A rigid ring formed from a rigid material having a cylindrical portion attached to a support member and a disc portion formed at one end of the cylindrical portion so as to be positioned on the atmospheric side, wherein the disc portion has a first surface positioned on the atmospheric side and a second surface opposite to the first surface, The elastic ring is made of an elastic material and comprises an intervening cylindrical portion which is joined to the cylindrical portion of the rigid ring and interposed between the cylindrical portion and the support member, and an elastic layer which is formed at one end of the intervening cylindrical portion which is positioned on the atmospheric side and joined to the first surface of the disc portion of the rigid ring. A sealing device disposed on the outside of the support member, The first surface of the disc portion of the rigid ring has a plurality of protrusions projecting toward the atmosphere, The elastic layer of the elastic ring is joined to the protrusions on the first surface of the disc portion and to the portion other than the protrusions. The support member is fitted into the cylindrical portion of the rigid ring. The disc portion of the rigid ring has an annular shape and is positioned radially outward from the cylindrical portion. The interposed cylindrical portion of the elastic ring is joined to the inner circumferential surface of the cylindrical portion and interposed between the inner circumferential surface of the cylindrical portion and the outer circumferential surface of the support member. The elastic layer of the elastic ring has an annular shape and is arranged radially outward of the intervening cylindrical portion. The distance between the projection of the rigid ring and the outer edge of the disc portion is greater than the distance between the projection and the inner edge of the disc portion. Sealing device.

5. The thickness of the portion of the elastic layer joined to the projection on the first surface of the disc is smaller than the thickness of the portion of the elastic layer joined to the portion of the first surface other than the projection. The sealing device according to any one of claims 2 to 4.

6. The surface of the elastic ring that is positioned on the atmospheric side of the elastic layer is flat. The sealing device according to any one of claims 2 to 4.

7. The second surface of the disc portion of the rigid ring has a recess on the back side of the projection. A sealing device according to any one of claims 1 to 4.

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