Sealing device for sealing hydrogen gas and hydrogen gas circulating pump for hydrogen fuel cell

Abstract

The utility model provides a sealing device for hydrogen sealing and a hydrogen circulating pump for a hydrogen fuel cell, which do not need a large occupied space and are low in cost. A sealing device (1) for hydrogen gas sealing is provided with: a holding member (2) having an annular shape about an axis (x); an annular member (3) which is held by the holding member (2), extends toward one side (FS) in the axial direction, and is made of a fluororesin material; an elastic body part (4) covering the holding member (2) and forming a seal lip (46) extending to the other side (SS) opposite to the one side in the axial direction; and a spring (5) that is disposed on the outer peripheral side of the seal lip (46) and biases the seal lip (46) toward the inner peripheral side.

Description

Technical Field

[0001] The utility model relates to a sealing device for hydrogen sealing and a hydrogen circulation pump for a hydrogen fuel cell, in particular to an oil-gas bidirectional sealing device for a hydrogen circulation pump for a hydrogen fuel cell. Background Art

[0002] For example, in Chinese Patent Application Publication No. 116447138 (CN116447138A), a sealing structure assembled in a hydrogen circulation pump of a hydrogen fuel cell is disclosed. Utility Model Content

[0003] Issues to be Solved by Utility Models

[0004] The sealing structure has a complicated structure, thus requiring a large occupied space and being high in cost.

[0005] The present invention is made in view of the above-mentioned problems, and its object is to provide a low-cost hydrogen sealing device that does not require a large occupied space.

[0006] Means for solving problems

[0007] In order to achieve the above-mentioned purpose, the sealing device for hydrogen sealing involved in the utility model includes: a retaining component, which is annular with an axis as the center; an annular component, which is retained by the retaining component, extends to one side in the axial direction, and is made of fluororesin material; an elastic body portion, which covers the retaining component and forms a sealing lip extending to the other side opposite to the one side in the axial direction; and a spring, which is arranged on the outer peripheral side of the sealing lip and applies force to the sealing lip toward the inner peripheral side.

[0008] In the hydrogen sealing sealing device of the utility model, the fluororesin material is PTFE.

[0009] In the hydrogen sealing device of the utility model, the retaining component comprises: an outer retaining component, which is annular with the axis as the center; an inner retaining component, which is fitted on the inner circumference of the outer retaining component and is annular with the axis as the center. The annular component is sandwiched between the outer retaining component and the inner retaining component in the axial direction.

[0010] In the hydrogen gas sealing device according to the present invention, the holding member is formed of stainless steel.

[0011] In the hydrogen gas sealing device according to the present invention, the spring is formed of stainless steel.

[0012] The utility model relates to a hydrogen circulation pump for a hydrogen fuel cell, comprising: a rotating shaft, which rotates around an axis; a shell, which has a through hole for inserting the rotating shaft; and a sealing device, which is used to seal between the rotating shaft and the through hole, wherein the sealing device comprises: a retaining component, which is annular with the axis as the center; an annular component, which is retained by the retaining component, extends to one side of the axial direction, contacts the rotating shaft, and is made of a fluororesin material; an elastic body portion, which covers the retaining component, forms a sealing lip extending to the other side opposite to the one side of the axial direction, and is sandwiched between the retaining component and the shell; and a spring, which is arranged on the outer peripheral side of the sealing lip and applies force to the sealing lip toward the inner peripheral side.

[0013] Utility Model Effect

[0014] According to the present invention, a low-cost hydrogen gas sealing device that does not require a large occupied space can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a cross-sectional view schematically showing the structure of a sealing device 1 according to one embodiment of the present invention.

[0016] Figure 2 This is an enlarged end view of one of the sealing devices 1 schematically showing the structure of the sealing device 1 according to one embodiment of the present invention.

[0017] Figure 3 It is a cross-sectional view schematically showing the structure of a hydrogen circulation pump 50 to which the sealing device 1 is applied.

[0018] Figure 4 This is a cross-sectional view showing a usage state of the sealing device 1 according to one embodiment of the present invention. DETAILED DESCRIPTION

[0019] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Figure 1 This is a cross-sectional view schematically showing the structure of a sealing device 1 according to one embodiment of the present invention. Figure 1 : is a cross-sectional view of the sealing device 1 along the axis x. As described later, the sealing device 1 involved in the utility model is assembled in, for example, a hydrogen circulation pump for resupplying unreacted hydrogen discharged from a fuel cell stack assembled in a fuel cell vehicle to the fuel cell stack. Specifically, the sealing device 1 is used in the hydrogen circulation pump to seal between a rotating shaft and a housing having a through hole for inserting the rotating shaft. The sealing device 1 is an oil-gas bidirectional sealing device for hydrogen sealing.

[0020] In the drawings, for convenience of explanation, one side in the direction along the axis x (hereinafter referred to as the "axial direction") is defined as a first side FS, and the other side opposite to the one side in the axial direction is defined as a second side SS. As described later, the first side FS is a gas side where a gas such as hydrogen exists, and the second side SS is a liquid side where a liquid such as a lubricant exists. In addition, in a direction orthogonal to the axis x (hereinafter referred to as the "radial direction"), the direction away from the axis x is defined as an outer peripheral side OC, and the direction close to the axis x is defined as an inner peripheral side IC. In addition, the direction around the axis x is defined as a circumferential direction.

[0021] Figure 2 FIG. 1 is an enlarged end view of one side of the sealing device 1 schematically showing the structure of the sealing device 1. Figure 1 and Figure 2 The sealing device 1 includes: a retaining member 2; an annular member 3 retained by the retaining member 2; and an elastic body portion 4 at least partially covering the retaining member 2. The retaining member 2, the annular member 3 and the elastic body portion 4 are all formed into a circular ring centered on the axis x. The retaining member 2 has an outer retaining member 10 disposed on the outer peripheral side OC and an inner retaining member 20 disposed on the inner peripheral side IC. By fitting the inner retaining member 20 to the outer retaining member 10, the annular member 3 is axially retained between the outer retaining member 10 and the inner retaining member 20.

[0022] The outer retaining member 10 has an annular cylindrical portion 11 extending in the axial direction and an annular flange portion 12 extending from the cylindrical portion 11 to the inner circumference side IC on the second side SS. The cylindrical portion 11 is formed as a whole in a cylindrical shape with the axis x as the center axis. In this example, the flange portion 12 is formed by bending the end of the second side SS of the cylindrical portion 11 in the radial direction. An annular protrusion 13 protruding toward the inner circumference side IC is formed on the cylindrical portion 11. The protrusion 13 extends in an annular shape from the end of the first side FS on the opposite side to the end of the second side SS bent by the flange portion 12 to the inner circumference side IC. The protrusion 13 extends, for example, along an imaginary plane orthogonal to the axis x.

[0023] The cylindrical portion 11 has an outer peripheral surface 11a and an inner peripheral surface 11b facing each other in the radial direction. The outer peripheral surface 11a is a surface facing the outer peripheral side OC, and the inner peripheral surface 11b is a surface facing the inner peripheral side IC. Steps are also formed on the outer peripheral surface 11a and the inner peripheral surface 11b by the step 11c formed on the cylindrical portion 11. The flange portion 12 has a side surface 12a and a side surface 12b facing each other in the axial direction. The side surface 12a is a surface facing the first side FS, and the side surface 12b is a surface facing the second side SS. The side surface 12b is connected to the outer peripheral surface 11a, and on the other hand, the side surface 12a is connected to the inner peripheral surface 11b. Steps are also formed on the side surfaces 12a and 12b by the step 12c formed on the flange portion 12.

[0024] The inner holding member 20 has an annular cylindrical portion 21 extending in the axial direction and an annular flange portion 22 extending from the cylindrical portion 21 to the inner circumference IC on the second side SS. The cylindrical portion 21 is formed as a whole in a cylindrical shape with the axis x as the center axis. In this example, the flange portion 22 is formed by bending in the radial direction from the end of the second side SS of the cylindrical portion 21. The cylindrical portion 21 is arranged closer to the inner circumference IC than the cylindrical portion 11 of the outer holding member 10. The flange portion 22 is arranged closer to the first side FS than the flange portion 12 of the outer holding member 10.

[0025] The cylindrical portion 21 has an outer peripheral surface 21a and an inner peripheral surface 21b facing each other in the radial direction. The outer peripheral surface 21a is a surface facing the outer peripheral side OC, and the inner peripheral surface 21b is a surface facing the inner peripheral side IC. In this example, the outer peripheral surface 21a is opposite to the inner peripheral surface 11b of the cylindrical portion 11 of the outer retaining member 10. The cylindrical portion 21 abuts against the side surface of the second side SS of the protrusion 13 at the end surface 21c facing the first side FS. The flange portion 22 has a side surface 22a and a side surface 22b facing each other in the axial direction. The side surface 22a is a surface facing the first side FS, and the side surface 22b is a surface facing the second side SS. The side surface 22b is connected to the outer peripheral surface 21a, and on the other hand, the side surface 22a is connected to the inner peripheral surface 21b. The side surface 22b is opposite to the side surface 12a of the flange portion 12 of the outer retaining member 10.

[0026] The annular component 3 has a base 31 that is annular around the axis x and a contact portion 32 that is continuous with the end of the inner circumference IC of the base 31. The base 31 is a plate-shaped portion that extends along an imaginary plane orthogonal to the axis x. The base 31 has a side surface 31a and a side surface 31b that face away from each other in the axial direction. In this example, the side surface 31a and the side surface 31b extend along an imaginary plane orthogonal to the axis x. The side surface 31a is a surface facing the first side FS, and the side surface 31b is a surface facing the second side SS. The end 31c on the outer circumferential side of the base 31 extends along a circle centered on the axis x. In this example, the end 31c abuts against the inner circumferential surface 11b of the cylindrical portion 11 of the outer retaining component 10.

[0027] The base 31 is sandwiched between the flange 12 of the outer holding member 10 and the flange 22 of the inner holding member 20 in the axial direction. At this time, the end face 21c of the cylindrical portion 21 abuts against the protrusion 13 of the cylindrical portion 11. In a state where the base 31 is sandwiched between the side 12a of the flange 12 and the side 22b of the flange 22, the axial distance between the side 12a of the flange 12 and the side 22b of the flange 22 is set to be smaller than the thickness of the base 31 in the axial direction. As a result, the base 31 is sandwiched between the flange 12 and the flange 22 in a state where it is compressed in the axial direction. Therefore, the annular member 3 can be firmly held between the flange 12 of the outer holding member 10 and the flange 22 of the inner holding member 20.

[0028] The contact portion 32 is a plate-like portion having a side surface 32a and a side surface 32b facing away from each other. The contact portion 32 extends obliquely toward the first side FS from the outer peripheral end connected to the base 31 toward the inner peripheral end 32c. In this example, the contact portion 32 has a shape that decreases in diameter in the axial direction toward the first side FS. The side surface 32b is a surface facing the inner peripheral side IC, and the side surface 32a is a surface facing the outer peripheral side OC. The side surface 32b is connected to the side surface 31b, and on the other hand, the side surface 32a is connected to the side surface 31a. The contact portion 32 is configured so that, when the sealing device 1 is installed in the use state of the application object, the inner peripheral end 32c of the inner peripheral side IC of the contact portion 32 is in contact with the outer peripheral surface of the rotating shaft of the application object in a slidable manner.

[0029] The elastic body portion 4 is formed of an annular elastic body centered on the axis x. The elastic body portion 4 is integrally mounted on the outer retaining member 10. Specifically, the elastic body portion 4 is integrally formed with the outer retaining member 10 in a manner that covers the outer retaining member 10 from the outer peripheral side OC and the second side SS. The elastic body portion 4 has a radial cover 41, an axial cover 42, and a sealing portion 43. The radial cover 41, the axial cover 42, and the sealing portion 43 are integrally formed.

[0030] In this example, the radial cover 41 covers the cylindrical portion 11 of the outer retaining member 10 from the outer peripheral side OC. The axial cover 42 covers the flange portion 12 of the outer retaining member 10 from the second side SS. The radial thickness of the radial cover 41 is set so that when the sealing device 1 is pressed into the inner peripheral surface of the through hole of the housing of the application object and compressed in the radial direction, a force toward the outer peripheral side OC, that is, a fitting force, of a predetermined magnitude is generated. In addition, in this example, the axial cover 42 also covers the end of the inner peripheral side IC of the flange portion 12 and a part of the inner peripheral side IC of the side surface 12a.

[0031] The sealing portion 43 includes a lip waist portion 44 and a sealing lip 45 extending from the lip waist portion 44 toward the second side SS in the axial direction. The lip waist portion 44 is a portion located near the end portion of the inner circumference side IC of the flange portion 12 of the outer retaining member 10. The sealing lip 45 includes a wedge-shaped lip front end portion 46 protruding toward the inner circumference side IC on the inner circumference side IC. The lip front end portion 46 is located at the innermost circumference side IC at a lip front end 47 that is a circle drawn with the axis x as the center in a plane orthogonal to the axis x. The sealing lip 45 is formed so that, in the use state, the vicinity of the lip front end 47 is in close contact with the outer circumference surface of the rotating shaft in a slidable manner.

[0032] The lip front end portion 46 defines an annular sealing side surface 48 facing the second side SS and an annular gas side surface 49 facing the first side FS, which are connected via the lip front end 47. The sealing side surface 48 is a conical surface in the shape of a truncated cone that decreases in diameter in the axial direction toward the first side FS. In addition, the gas side surface 49 is a conical surface in the shape of a truncated cone that decreases in diameter in the axial direction toward the second side SS. The lip front end 47 is formed at the intersection of the sealing side surface 48 and the gas side surface 49. As described later, the sealing portion 43 is formed integrally with the radial cover 41 and the axial cover 42.

[0033] The sealing device 1 includes an annular spring 5, which is attached to an annular groove 45a on the outer peripheral side OC of the sealing lip 45. The spring 5 is arranged, for example, at a position opposite to the lip tip 47 in the radial direction across the sealing lip 45. The spring 5 applies force to the lip tip 46, that is, the lip tip 47, toward the inner peripheral side IC. Thus, the spring 5 applies a pressing force of a predetermined magnitude, for example, to the lip tip 46, that is, the lip tip 47, on the outer peripheral surface of the rotating shaft.

[0034] The outer retaining member 10 and the inner retaining member 20 are manufactured, for example, by stamping and forging of metal materials. The metal material includes, for example, stainless steel. The annular member 3 is formed, for example, of a fluororesin material. The fluororesin material includes, for example, PTFE (polytetrafluoroethylene). The elastomer portion 4 is formed, for example, of an elastic resin material. The elastic resin material includes, for example, synthetic rubbers such as nitrile rubber (NBR), hydrogenated nitrile rubber (H-NBR), acrylic rubber (ACM), and fluororubber (FKM). The elastomer portion 4 is formed, for example, by crosslinking (vulcanization) molding using a molding die equipped with the outer retaining member 10. The spring 5 is formed of a metal material such as stainless steel.

[0035] When assembling the sealing device 1, as described above, the elastic body portion 4 is formed by using a forming die provided with the outer retaining member 10, and the elastic body portion 4 is bonded to the outer retaining member 10 by cross-linking bonding. The annular member 3 is arranged on the flange portion 12 of the outer retaining member 10 from the first side FS. Then, the inner retaining member 20 is embedded in the outer retaining member 10 from the first side FS. The thickness of the base portion 31 of the annular member 3 is greater than the distance between the flange portion 12 and the flange portion 22 in the axial direction. As a result, the flange portion 22 of the inner retaining member 20 compresses the base portion 31 of the annular member 3 in the axial direction and embeds it in the outer retaining member 10. The end face 21c of the first side FS of the cylindrical portion 21 abuts against the protrusion 13 of the outer retaining member 10. The spring 5 is installed in the groove 45a of the elastic body portion 4. The sealing device 1 is thus assembled.

[0036] Next, the operation of the sealing device 1 will be described below. Figure 31 is a cross-sectional view schematically showing the structure of a hydrogen circulation pump 50 to which the sealing device 1 is applied. The hydrogen circulation pump 50 is assembled in, for example, a hydrogen fuel cell. The hydrogen fuel cell includes, for example, a fuel cell stack that generates electricity by reacting oxygen with hydrogen; an air compressor that supplies oxygen to the fuel cell stack; a high-pressure hydrogen tank that supplies hydrogen to the fuel cell stack; a gas-liquid separation device that separates water discharged from the fuel cell stack from unreacted hydrogen; and a hydrogen circulation pump 50 that supplies unreacted hydrogen to the fuel cell stack. The hydrogen circulation pump 50 is a pump for returning unreacted hydrogen separated from water by the gas-liquid separation device to the fuel cell stack.

[0037] The hydrogen circulation pump 50 has a motor housing 51 and a pump housing 52 mounted on the motor housing 51. A motor 53 is arranged in the motor housing 51. The motor 53 has a rotor 55 fixed to a rotating shaft 54 ​​and a stator 56 fixed to the motor housing 51. The rotating shaft 54 ​​extends from the motor housing 51 to the pump housing 52. One end of the rotating shaft 54 ​​is rotatably supported in the motor housing 51 via a bearing 57, and on the other hand, the other end of the rotating shaft 54 ​​is rotatably supported in the pump housing 52 via a bearing 58. In addition, between one end and the other end, the rotating shaft 54 ​​is supported by a pair of bearings 59, for example. The rotating shaft 54 ​​can rotate around its axis through the magnetic interaction between the permanent magnet of the rotor 55 and the coil of the stator 56.

[0038] A pump chamber 52a and a gear chamber 52b are defined in the pump housing 52. A rotating shaft 60 extending parallel to the rotating shaft 54 ​​is arranged in the pump housing 52. The rotating shaft 60 extends from the gear chamber 52b into the pump chamber 52a. The rotating shaft 60 is supported in the pump housing 52 in a rotatable manner via a pair of bearings 61 in the gear chamber 52b. Specifically, the rotating shaft 60 is cantilevered by a pair of bearings 61. In the gear chamber 52b, a gear 63 and a gear 64 are respectively installed on the rotating shaft 54 ​​and the rotating shaft 60. The gear 63 and the gear 64 mesh with each other. As a result, the rotation around the axis of the rotating shaft 54 ​​is transmitted to the rotating shaft 60. Thus, the rotating shaft 60 can rotate around its axis. In addition, the gear chamber 52b is filled with a liquid such as a lubricant such as grease.

[0039] The pump chamber 52a is connected to the fuel cell stack. In the pump chamber 52a, a driving rotor 65 and a driven rotor 66 are respectively installed on the rotating shaft 54 ​​and the rotating shaft 60. The driving rotor 65 is rotated by the rotation of the rotating shaft 54, and the rotating shaft 60 is rotated based on the rotation of the rotating shaft 54, thereby rotating the driven rotor 66. As a result, the unreacted hydrogen sucked into the pump chamber 52a from the fuel cell stack is discharged from the pump chamber 52a toward the fuel cell stack. In this example, the through holes 67, 68 of the pump housing 52 in which the rotating shafts 54 and 60 are arranged between the pump chamber 52a and the gear chamber 52b, and the through hole 69 of the pump housing 52 that connects the gear chamber 52b with the space in the motor housing 51 is applied with the above-mentioned sealing device 1.

[0040] Figure 4 2 is a cross-sectional view showing the usage of the sealing device 1. Figure 4 , a scene is shown in which the sealing device 1 is used to seal the through hole 67 between the pump chamber 52a and the gear chamber 52b. Specifically, the sealing device 1 is installed on the inner circumferential surface 67a of the through hole 67 by pressing. As a result, the radial cover 41 of the elastomer portion 4 is radially compressed between the cylindrical portion 11 of the outer retaining component 10, generating a force toward the outer peripheral side OC, that is, a fitting force. When the rotating shaft 54 ​​rotates around the axis x, the inner circumferential end 32c of the annular component 3 slides on the outer circumferential surface 54a of the rotating shaft 54. As a result, the hydrogen in the pump chamber 52a is sealed. In addition, the elastomer portion 4 slides on the outer circumferential surface 54a of the rotating shaft 54 ​​at the lip front end 47 of the lip front end portion 46. As a result, the lubricant in the gear chamber 52b is sealed. As a result, the hydrogen in the pump chamber 52a and the fluid (oil) such as the lubricant in the gear chamber 52b are sealed.

[0041] In the sealing device 1 as described above, the annular member 3 is sandwiched between the outer retaining member 10 and the inner retaining member 20 in the axial direction. The outer peripheral side OC of the outer retaining member 10 is covered by the radial cover 41 of the elastic body portion 4. According to such a structure, if the sealing device 1 is installed on the inner peripheral surface 67a of the through hole 67 by pressing, the fitting force is generated by the compression of the radial cover 41 of the elastic body portion 4. In this example, the sealing device 1 further abuts the end surface 67b of the first side FS of the through hole 67 at the protrusion 13 of the outer retaining member 10. Thus, the sealing device 1 can be easily installed in the through hole 67. The sealing device 1 is a simple structure in which the annular member 3 extending to the first side FS is sandwiched between the outer retaining member 10 and the inner retaining member 20, and the sealing lip 45 extending to the second side SS is formed on the elastic body portion 4, so the space occupied by the sealing device 1 can be reduced compared with the past. In addition, since the number of components is small, the assembly cost of the sealing device 1 can be reduced.

[0042] The present invention has been described above by the above embodiments, but the technical scope of the present invention is not limited to the scope described in the above embodiments. It should be understood by those skilled in the art that various changes or improvements can be made to the above embodiments. It can be seen from the description of the claims that the method to which such changes or improvements are made can also be included in the technical scope of the present invention.

[0043] The above-described embodiments are used to facilitate understanding of the present invention, and are not used to limit the interpretation of the present invention. In addition, the above-described embodiments do not limit the objects of use utilized by the present invention, and the present invention may include all of them as its objects of use. The various components and their configurations, materials, conditions, shapes, and sizes possessed by the above-described embodiments are not limited to the illustrated contents, and may be appropriately changed. For example, the present invention includes differences arising from the implementation of manufacturing tolerances, etc. In addition, within the scope of technical non-contradiction, the components shown in different embodiments may be partially replaced or combined with each other. In addition, the various structures may be appropriately and selectively combined in a manner that achieves at least a portion of the above-mentioned topics and effects.

[0044] Reference numerals:

[0045] 1 sealing device; 2 holding member; 3 annular member; 4 elastic body; 5 spring; 10 outer holding member; 11 cylindrical portion; 11a outer peripheral surface; 11b inner peripheral surface; 11c step; 12 flange portion; 12a side surface; 12b side surface; 13 protrusion; 20 inner holding member; 21 cylindrical portion; 21a outer peripheral surface; 21b inner peripheral surface; 21c end surface; 22 flange portion; 31 base; 31a side surface; 31b side surface; 31c end surface; 32 contact portion; 32a side surface; 32b side surface; 32c inner peripheral end; 41 radial cover; 42 axial cover; 43 sealing portion; 44 lip waist; 45 sealing lip; 46 lip front end; 47 lip front end; 48 sealing side; 49 gas side; 50 hydrogen circulation pump; 51 motor housing; 52 pump housing; 52a pump chamber; 52b gear chamber; 53 motor; 54 rotating shaft; 54a outer peripheral surface; 55 rotor; 56 stator; 57, 58, 59 bearings; 60 rotating shaft; 61 bearings; 63, 64 gears; 65, 66 rotor; 67, 68, 69 through holes; 67a inner peripheral surface; 67b end face; FS first side; SS second side; OC outer peripheral side; IC inner peripheral side; x axis line.

Claims

1. A sealing device for hydrogen sealing, characterized in that: include: A retaining member is annular with the axis as the center; an annular member, held by the holding member, extending to one side in the axial direction and made of a fluororesin material; an elastic body portion covering the retaining member and forming a sealing lip extending to the other side opposite to the one side in the axial direction; as well as The spring is disposed on the outer peripheral side of the seal lip and urges the seal lip toward the inner peripheral side.

2. The hydrogen sealing device according to claim 1, characterized in that: The fluororesin material is PTFE.

3. The hydrogen sealing device according to claim 1, characterized in that: The holding component comprises: an outer retaining member, which is annular with the axis as the center; The inner holding member is fitted into the inner circumference of the outer holding member and is annular with the axis as the center. The annular member is sandwiched between the outer holding member and the inner holding member in the axial direction.

4. The hydrogen sealing device according to claim 1, characterized in that: The retaining member is formed of stainless steel.

5. The hydrogen sealing device according to claim 1, characterized in that: The spring is formed from stainless steel.

6. A hydrogen circulation pump for a hydrogen fuel cell, characterized in that: include: Axis of rotation, rotation around an axis; A housing having a through hole for inserting the rotating shaft; as well as A sealing device, used for sealing between the rotating shaft and the through hole, The sealing device comprises: A retaining member, which is annular with the axis as the center; an annular member, held by the holding member, extending to one side in the axial direction, in contact with the rotating shaft, and made of a fluororesin material; an elastic body portion covering the retaining member, forming a sealing lip extending to the other side opposite to the one side in the axial direction, and being sandwiched between the retaining member and the housing; and The spring is disposed on the outer peripheral side of the seal lip and urges the seal lip toward the inner peripheral side.

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