Sealing device and sealing structure

Abstract

To maintain a sealing performance by a sealing device effectively in a structure in which a load in a circumferential direction acts on the sealing device locally.SOLUTION: A sealing device 30 is installed between a support member 10 provided with a shaft hole 11 and a shaft member 20 which rotates around a center axis C in both directions at the inner side of the shaft hole 11. The sealing device 30 has a wave shape in which a position in an axial direction periodically changes according to a position in a circumferential direction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a sealing device and a sealing structure. [Background technology]

[0002] Sealing devices have been proposed for sealing the annular gap between a support member having a circular axial hole formed therein and a shaft member inserted into the axial hole. For example, Patent Document 1 discloses a structure in which a shaft member is inserted into a axial hole formed in a housing, and an annular sealing member is installed in an annular groove formed on the outer circumferential surface of the shaft member. The sealing member is an O-ring with a circular cross section. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2021-167648 Summary of the Invention [Problem to be solved by the invention]

[0004] In a structure in which the shaft member rotates around the central axis, a load may act locally on a specific circumferential portion of the sealing device in a direction that stretches that portion in the circumferential direction. As a result of a portion of the sealing device stretching due to the circumferential load, the wire diameter of that portion may be locally reduced. Therefore, there is a possibility that the spaces separated by the sealing device may communicate with each other through a path formed by the reduction in wire diameter. This tendency is particularly pronounced in a structure in which the shaft member rotates in both directions around the central axis. Taking the above circumstances into consideration, one aspect of the present disclosure aims to effectively maintain the sealing performance of a sealing device even in a structure in which a circumferential load acts locally on the sealing device. [Means for solving the problem]

[0005] In order to solve the above problems, a sealing device according to one aspect of the present disclosure is an endless sealing device installed between a support member having an axial hole and an axial member that rotates in both directions around a central axis inside the axial hole, and has a wave shape in which the axial position changes periodically depending on the circumferential position.

[0006] A sealing device according to another aspect of the present disclosure is an endless sealing device installed between a support member having an axial hole formed therein and an axial member that rotates in both directions around a central axis inside the axial hole, and includes a first part and a second part that are positioned differently in the circumferential direction, the first part being a part that is convexly curved toward a first direction along the central axis, and the second part being a part that is convexly curved toward a second direction opposite to the first direction.

[0007] A sealing device according to another aspect of the present disclosure is an endless sealing device installed between a support member having an axial hole formed therein and an axial member that rotates in both directions around a central axis inside the axial hole, and includes a first portion that is a circumferential part and a second portion that is a circumferential part that is different in position from the first portion, and the position of the first portion in the axial direction is different from the position of the second portion in the axial direction.

[0008] A sealing structure according to one aspect of the present disclosure comprises a support member having an axial hole, an axial member that rotates in both directions around a central axis inside the axial hole, and an endless sealing device installed between the support member and the axial member, the sealing device having a wave shape whose axial position changes periodically depending on its circumferential position. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 2 is a side view of the sealing structure according to the embodiment. [Figure 2] 1A and 1B are plan and side views of a sealing device; [Figure 3] FIG. 10 is a side view of a sealing structure in a comparative example. [Figure 4]10A and 10B are explanatory diagrams illustrating a state of a sealing device when a tensile stress is applied. [Figure 5] 10A and 10B are explanatory diagrams illustrating a state of a sealing device when a compressive stress is applied. [Figure 6] FIG. 10 is a side view of a sealing device according to a modified example. [Figure 7] FIG. 10 is a side view of a sealing device according to a modified example. [Figure 8] FIG. 10 is a side view of a sealing structure according to a modified example. [Figure 9] FIG. 10 is a side view of a sealing structure according to a modified example. [Figure 10] FIG. 10 is a side view of a sealing structure according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0010] The embodiments for carrying out the present disclosure will be described with reference to the drawings. Note that the dimensions and scale of each element in each drawing may differ from those of the actual product. Furthermore, the embodiment described below is an exemplary embodiment that may be envisioned when carrying out the present disclosure. Therefore, the scope of the present disclosure is not limited to the embodiment exemplified below.

[0011] A: Embodiment 1 is a side view of a sealing structure 100 according to one embodiment of the present disclosure. The sealing structure 100 is used in various mechanisms in which elements can rotate about an axis, such as a reclining seat in which the back portion is rotatably supported relative to the seat portion. The uses of the sealing structure 100 are arbitrary and are not limited to the above examples.

[0012] As illustrated in FIG. 1, the sealing structure 100 includes a support member 10, a shaft member 20, and a sealing device 30. The support member 10 is a hollow housing in which a shaft hole 11 is provided. The shaft hole 11 is an opening with a circular cross section. The shaft member 20 is a cylindrical shaft inserted into the shaft hole 11. The shaft member 20 rotates around a central axis. The inner diameter of the shaft hole 11 is greater than the outer diameter of the shaft member 20. Therefore, an annular space (gap) S is formed between the inner circumferential surface of the shaft hole 11 and the outer circumferential surface of the shaft member 20. The sealing device 30 is an endless (i.e., loop-shaped) elastic body provided between the support member 10 and the shaft member 20.

[0013] 1 shows the central axis C of the sealing device 30. Because the sealing device 30 is installed coaxially with the shaft member 20, the central axis C can also be described as the central axis of the shaft member 20 or the shaft hole 11. In the following description, the direction along the central axis C will be referred to as the "axial direction." The axial direction is divided into a Z1 direction and a Z2 direction that face opposite each other.

[0014] In the following description, the direction of the circumference of an imaginary circle of any diameter centered on the central axis C will be referred to as the "circumferential direction." The imaginary circle is an imaginary circle that exists in a plane perpendicular to the central axis C. The circumferential direction is divided into directions C1 and C2 that face opposite each other. The direction of the radius of an imaginary circle of any diameter centered on the central axis C will be referred to as the "radial direction." In the radial direction, the direction toward the central axis C will be referred to as the "inner side," and the direction facing away from the central axis C will be referred to as the "outer side."

[0015] The shaft member 20 rotates in both directions within the shaft hole 11. Specifically, the shaft member 20 rotates in both directions C1 and C2 within a range of a predetermined angle (hereinafter referred to as "swing angle α") centered on the central axis C. For example, the shaft member 20 alternately rotates in the C1 direction (e.g., forward rotation) and in the C2 direction (e.g., reverse rotation).

[0016] A mounting groove 21 is formed on the outer peripheral surface of the shaft member 20. The mounting groove 21 is a recess that is continuous around the entire circumference of the shaft member 20. The width of the mounting groove 21 is constant around the entire circumference of the shaft member 20. The sealing device 30 is housed inside the mounting groove 21.

[0017] The sealing device 30 seals the space S between the support member 10 and the shaft member 20. That is, the space S between the support member 10 and the shaft member 20 is divided by the sealing device 30 into a first space S1 and a second space S2.

[0018] The first space S1 is an internal space located in the Z1 direction of the sealing device 30. The first space S1 is filled with lubricating oil 40. On the other hand, the second space S2 is a space located in the Z2 direction of the sealing device 30.

[0019] The second space S2 is, for example, an external space open to the atmosphere. Foreign matter such as muddy water or dust is present in the second space S2. The sealing device 30 is an endless structure that prevents leakage of the lubricating oil 40 from the first space S1 to the second space S2 and prevents entry of foreign matter from the second space S2 into the first space S1.

[0020] The sealing device 30 is formed of an elastic material such as a rubber material. Examples of materials for the sealing device 30 include various rubber materials such as chloroprene rubber (CR), silicone rubber (SR), acrylic rubber (ACM), urethane rubber (U), polyurethane rubber (PUR), vinyl methyl silicone rubber (VMQ), ethylene propylene diene rubber (EPDM), and fluororubber (FKM). The sealing device 30 is an integrally molded product formed by a molding technique such as injection molding or compression molding. In other words, the sealing device 30 does not include a metal reinforcing ring for reinforcing the elastic body or a fastener such as a garter spring for fastening the elastic body to the shaft member 20.

[0021] FIG. 2 is a plan view and a side view of the sealing device 30. As illustrated in FIG. 2, the sealing device 30 has a wave shape in which the position in the axial direction repeatedly changes depending on the position in the circumferential direction. That is, the sealing device 30 has a shape that meanders periodically in the circumferential direction. As illustrated in FIG. 2, the shape of the sealing device 30 in a plan view from the axial direction is annular, and the shape of the sealing device 30 in a side view from the radial direction is a wave shape composed of continuous curves. The cross-sectional shape of each part of the sealing device 30 is circular, and the wire diameter Φ of the sealing device 30 is constant around the entire circumference.

[0022] The sealing device 30 includes a plurality of first portions 31 and a plurality of second portions 32. Each first portion 31 is a circumferential portion of the sealing device 30. Similarly, each second portion 32 is a circumferential portion of the sealing device 30. The first portions 31 and the second portions 32 are alternately arranged along the circumferential direction. That is, the first portions 31 and the second portions 32 are located at different circumferential positions. Specifically, the first portions 31 and the second portions 32 are alternately arranged at 30° intervals along the circumferential direction. Therefore, the sealing device 30 includes six first portions 31 and six second portions 32. However, the number of first portions 31 and the number of second portions 32 may be changed as desired. Furthermore, the arrangement angle between the first portions 31 and the second portions 32 is not limited to 30° as illustrated in FIG. 2 and may be changed as desired. Furthermore, the angle between the first portions 31 and the second portions 32 may vary depending on the circumferential position of the sealing device 30.

[0023] Each first portion 31 is a portion that is curved convexly in the Z1 direction. On the other hand, each second portion 32 is a portion that is curved convexly in the Z2 direction. The first portions 31 and second portions 32 that are adjacent to each other in the circumferential direction are connected by a curved portion of the sealing device 30. If the Z1 direction is assumed to be vertically upward and the Z2 direction is assumed to be vertically downward, the first portions 31 are peaks and the second portions 32 are valleys. Therefore, the center of curvature of each first portion 31 is located in the Z2 direction of the sealing device 30, and the center of curvature of each second portion 32 is located in the Z1 direction of the sealing device 30. In other words, the position of the first portion 31 in the axial direction is located further in the Z1 direction than the position of the second portion 32 in the axial direction.

[0024] 2 shows a reference plane R. The reference plane R is an imaginary plane that passes through the midpoint of the range in which the sealing device 30 exists in the axial direction and is perpendicular to the axial direction. Each first portion 31 is a portion located in the Z1 direction of the reference plane R, and each second portion 32 is a portion located in the Z2 direction of the reference plane R. In the above configuration, the lubricating oil 40 filled in the first space S1 is held in the space on the inner circumferential side (Z1 direction) of the second portion 32, as illustrated in FIG. 1.

[0025] As described above, the sealing device 30 is not a simple annular seal (hereinafter referred to as an "annular seal"), but a three-dimensional seal that is repeatedly curved in the axial direction. Therefore, the circumferential length L of the sealing device 30 is greater than the circumferential length L0 of an annular seal having the same diameter (inner diameter or outer diameter) as the sealing device 30. Note that the circumferential length L of the sealing device 30 is the total length of a curve connecting the centers of cross sections at any position on the sealing device 30 over the entire circumference, as illustrated in FIG. 2.

[0026] 3 is a side view of a configuration (hereinafter referred to as the "Comparative Example") in which an annular seal 60 is installed between a support member 10 and a shaft member 20. In the Comparative Example, when the shaft member 20 repeatedly rotates in both directions C1 and C2 about a central axis C, stress in a direction that stretches the annular seal 60 in the circumferential direction (hereinafter referred to as "tensile stress") or stress in a direction that compresses the annular seal 60 in the circumferential direction (hereinafter referred to as "compressive stress") acts locally on the annular seal 60. One of the causes of the non-uniformity in the direction (compression / extension) and position of the stress in the circumferential direction as described above is presumably that the frictional resistance acting on the contact surface between the support member 10 or the shaft member 20 and the annular seal 60 is non-uniform in the circumferential direction, for example.

[0027] When stress with uneven direction and position acts on the annular seal 60 as described above, localized elongation occurs in the portion 61 of the annular seal 60 where the tensile stress acts. Therefore, as shown by the dashed line in Figure 3, the wire diameter Φ of the portion 61 of the annular seal 60 locally decreases. On the other hand, localized compression occurs in the portion 62 of the annular seal 60 where the compressive stress acts. Therefore, as shown by the dashed line in Figure 3, the wire diameter Φ of the portion 62 of the annular seal 60 locally increases. As explained above, in the comparative example, the wire diameter Φ locally decreases or increases depending on the circumferential position of the annular seal 60.

[0028] In the portion 61 of the annular seal 60 where the wire diameter Φ is reduced, a passage (hereinafter referred to as a "communicating passage") that connects the first space S1 and the second space S2 may be formed, as shown by the dashed arrow in Fig. 3. In other words, in the comparative example, the ability of the annular seal 60 to seal the first space S1 and the second space S2 (sealing performance) may be reduced due to a load (tensile stress) that is locally generated in the annular seal 60. For example, there is a possibility that the lubricating oil 40 in the first space S1 may leak into the second space S2 through the communicating passage.

[0029] 4 and 5 are explanatory diagrams of the behavior of the sealing device 30 when the shaft member 20 rotates in both directions (C1 direction / C2 direction) about the central axis C in the sealing structure 100 of this embodiment.

[0030] When a tensile stress acts on the sealing device 30 from the support member 10 or the shaft member 20, the sealing device 30 is deformed so that the amplitude of the waveform decreases and the period increases (the waveform approaches the reference plane R), as illustrated in Fig. 4. On the other hand, when a compressive stress acts on the sealing device 30 from the support member 10 or the shaft member 20, the sealing device 30 is deformed so that the amplitude of the waveform increases and the period decreases, as illustrated in Fig. 5.

[0031] As described above, the corrugated shape of the sealing device 30 itself is deformed, thereby suppressing a local change in the wire diameter Φ of the sealing device 30. That is, even if a tensile stress acts on the sealing device 30, for example, a local decrease in the wire diameter Φ of the sealing device 30 is suppressed. As can be understood from the above explanation, in the sealing device 30, an extensibility is ensured by the corrugated shape.

[0032] As a result of suppressing the local change in the wire diameter Φ as described above, according to this embodiment, it is possible to reduce the possibility that a communication path between the first space S1 and the second space S2 will be formed due to a local decrease in the wire diameter Φ. That is, even in a structure in which a circumferential load acts locally on the sealing device 30 due to bidirectional rotation (swing) of the shaft member 20, it is possible to effectively maintain the sealing performance of the sealing device 30. For example, it is possible to suppress leakage of the lubricating oil 40 from the first space S1 to the second space S2.

[0033] Moreover, in the first embodiment, the lubricating oil 40 filled in the first space S1 is retained in the space on the inner circumferential side (Z1 direction) of the second portion 32. In the above configuration, an oil film of the lubricating oil 40 is formed between the support member 10 or the shaft member 20 and the sealing device 30, so that wear of the sealing device 30 caused by contact with the support member 10 or the shaft member 20 is suppressed. Therefore, a longer life of the sealing device 30 can be achieved. Furthermore, the formation of the oil film of the lubricating oil 40 reduces the load acting on the sealing device 30 from the support member 10 or the shaft member 20. Therefore, the above-mentioned effect of suppressing local reduction in the wire diameter Φ caused by the circumferential load is particularly remarkable.

[0034] The circumferential length L of the sealing device 30 will be explained. In the following explanation, for convenience, reference will be made to the annular seal 60, which has the same wire diameter Φ as the sealing device 30. The circumferential length L0 of the annular seal 60 is expressed by the following formula (1) using the diameter D of the shaft member 20 (specifically, the diameter of the mounting groove 21). The planar shape of the sealing device 30 as viewed from the axial direction is a ring with the circumferential length L0 of formula (1). L0 = (D + Φ) × π … (1)

[0035] As described above, the circumferential length L of the sealing device 30 in the embodiment is greater than the circumferential length L0 of the annular seal 60. That is, the circumferential length L of the sealing device 30 is expressed by the following mathematical formula (2). L = L0 + δ …(2)

[0036] The surplus δ (δ=L−L0) of the circumferential length L of the sealing device 30 relative to the circumferential length L0 of the annular seal 60 is set according to the swing angle α of the shaft member 20. Specifically, the larger the swing angle α of the shaft member 20, the larger the surplus δ of the sealing device 30 is set to be. For example, the surplus δ is expressed by the following mathematical formula (3). δ=(D+φ)×π×α / 360° …(3)

[0037] According to the embodiment in which the circumferential length L of the sealing device 30 is set by the above-mentioned method, in a situation in which the shaft member 20 rotates in both directions within the range of the swing angle α, the circumferential load acting on the sealing device 30 from the support member 10 or the shaft member 20 can be absorbed by the wave-shaped deformation of the sealing device 30 without causing a reduction in the wire diameter Φ due to tensile stress in the circumferential direction. Therefore, the generation of a communication path between the first space S1 and the second space S2 is suppressed, and as a result, the sealing performance of the sealing device 30 can be effectively maintained.

[0038] It is preferable that the filling rate of the sealing device 30 in the mounting groove 21 is 90% or more. The filling rate is the ratio of the volume of the sealing device 30 in the mounting groove 21 to the volume of the mounting groove 21.

[0039] B: Modified example Specific modified embodiments that can be added to the embodiments exemplified above are shown below. Two or more embodiments arbitrarily selected from the following examples may be combined as appropriate within the scope of not being mutually contradictory.

[0040] (1) In the above-described embodiment, the sealing device 30 is curved all around, but as shown in Fig. 6, the sealing device 30 may be configured by combining curved portions and straight portions. In the embodiment shown in Fig. 6, the first portion 31 and the second portion 32 are curved, and the portion connecting the first portion 31 and the second portion 32 is straight.

[0041] (2) In the above-described embodiment, the first portions 31 and the second portions 32 are arranged at a constant period in the circumferential direction, but the interval between the first portions 31 and the second portions 32 in the circumferential direction does not have to be constant. In other words, the first portions 31 and the second portions 32 may be arranged non-periodically.

[0042] (3) In the above embodiment, the sealing device 30 has a circular cross-sectional shape, but the cross-sectional shape of the sealing device 30 is not limited to the above example. For example, the cross-sectional shape of the sealing device 30 may be a polygonal shape.

[0043] (4) In the above-described embodiment, the sealing device 30 has a constant wire diameter Φ over the entire circumference, but the sealing device 30 may include portions with different wire diameters Φ. For example, as illustrated in Fig. 7, a configuration is envisioned in which the wire diameter Φ1 of the first portion 31 and the second portion 32 of the sealing device 30 is larger than the wire diameter Φ2 of the other portions.

[0044] (5) In the above-described embodiment, the mounting groove 21 for accommodating the sealing device 30 is provided in the shaft member 20, but the structure for holding the sealing device 30 between the support member 10 and the shaft member 20 is not limited to the above example.

[0045] For example, as illustrated in Figure 8, a configuration is envisioned in which a mounting groove 12 is formed on the inner peripheral surface of a shaft hole 11 in a support member 10. In the configuration of Figure 8, a mounting groove 21 is not formed on the outer peripheral surface of a shaft member 20. A sealing device 30 is housed inside the mounting groove 12. Specifically, the sealing device 30 is housed in the annular space between the outer peripheral surface of the shaft member 20 and the mounting groove 12 of the support member 10.

[0046] 9, a configuration is also envisioned in which mounting grooves (12, 21) are formed in both the support member 10 and the shaft member 20. Specifically, the mounting groove 12 is formed on the inner circumferential surface of the shaft hole 11 in the support member 10, and the mounting groove 21 is formed on the outer circumferential surface of the shaft member 20. The sealing device 30 is housed in the annular space between the mounting groove 12 of the support member 10 and the mounting groove 21 of the shaft member 20.

[0047] 10 , the sealing device 30 may be housed in an annular space formed by a step 15 formed on the inner circumferential surface of the axial hole 11 in the support member 10 and a step 25 formed on the outer circumferential surface of the axial member 20. That is, the sealing device 30 is housed in the space between the step 15 and the step 25 in the axial direction.

[0048] 9, in which both the mounting groove 12 of the support member 10 and the mounting groove 21 of the shaft member 20 are formed, the sealing device 30 may come into contact with the corners of the mounting groove 12 and the mounting groove 21, resulting in damage to the surface of the sealing device 30. Therefore, from the perspective of suppressing damage to the sealing device 30, a configuration in which the mounting groove 12 is formed in the support member 10, as illustrated in FIG.

[0049] (6) In the above-described embodiment, the shaft member 20 rotates in both directions around the central axis C, but a configuration in which the shaft member 20 rotates in both directions is not essential to the present disclosure. For example, the sealing device 30 exemplified above may be applied to a configuration in which the shaft member 20 rotates in one direction or a configuration in which the shaft member 20 does not rotate.

[0050] (7) The term "nth" (n is a natural number) in this application is used only as a formal and convenient label to distinguish each element in the description and does not have any substantive meaning. Therefore, there is no room for restrictive interpretation of the position of each element or the order of manufacture, etc., based on the term "nth."

[0051] C: Notes From the above-described exemplary embodiments, the following configurations can be understood, for example.

[0052] A sealing device according to one embodiment (embodiment 1) of the present disclosure is an endless sealing device installed between a support member having an axial hole and an axial member that rotates in both directions around a central axis inside the axial hole, and has a wave shape in which the axial position changes periodically depending on the circumferential position.

[0053] In the above-described aspects, the sealing device is formed in a wave-like shape whose axial position changes periodically according to the circumferential position. In the above-described configuration, when a load that stretches a portion of the sealing device in the circumferential direction acts on the sealing device from the support member or the shaft member, the sealing device deforms so that the amplitude of the wave-like shape decreases and the period increases (specifically, the wave shape approaches a reference plane perpendicular to the axial direction). Therefore, compared to a sealing device formed in a simple annular shape, local reduction in wire diameter due to circumferential load is suppressed. In other words, the possibility of a passage connecting each space partitioned by the sealing device being formed due to a local reduction in wire diameter can be reduced. In other words, even in a structure in which a circumferential load acts locally on the sealing device due to bidirectional rotation (swing) of the shaft member, the sealing performance of the sealing device can be effectively maintained.

[0054] A sealing device according to another aspect (aspect 2) of the present disclosure is an endless sealing device installed between a support member having an axial hole formed therein and an axial member that rotates in both directions around a central axis inside the axial hole, and includes a first part and a second part that are positioned differently in the circumferential direction, the first part being a part that is convexly curved toward a first direction along the central axis, and the second part being a part that is convexly curved toward a second direction opposite to the first direction.

[0055] In the above aspects, the sealing device includes a first portion curved convexly in a first direction and a second portion curved convexly in a second direction. In the above configuration, when a load that stretches a portion of the sealing device in the circumferential direction acts on the sealing device from the support member or the shaft member, the sealing device deforms so that the curvature of the first portion or the second portion decreases. Therefore, compared to a sealing device formed in a simple annular shape, localized reduction in wire diameter due to circumferential load is suppressed. In other words, the possibility of a passage connecting each space partitioned by the sealing device being formed due to a localized reduction in wire diameter can be reduced. In other words, even in a structure in which a circumferential load acts locally on the sealing device due to bidirectional rotation (swing) of the shaft member, the sealing performance of the sealing device can be effectively maintained.

[0056] A sealing device according to another aspect (aspect 3) of the present disclosure is an endless sealing device installed between a support member having an axial hole formed therein and an axial member that rotates in both directions around a central axis inside the axial hole, and includes a first part that is a circumferential part and a second part that is a circumferential part that is different in position from the first part, and the position of the first part in the axial direction is different from the position of the second part in the axial direction.

[0057] In the above-described aspect, the first and second portions of the sealing device, which are located at different circumferential positions, are located at different axial positions. In the above-described configuration, when a load that stretches a part of the sealing device in the circumferential direction acts on the sealing device from the support member or the shaft member, the sealing device deforms so that the distance between the first and second portions in the axial direction decreases. Therefore, compared to a sealing device formed in a simple annular shape, local reduction in wire diameter due to a circumferential load is suppressed. In other words, the possibility that a passage connecting each space partitioned by the sealing device will be formed due to a local reduction in wire diameter can be reduced. In other words, even in a structure in which a circumferential load acts locally on the sealing device due to bidirectional rotation (swing) of the shaft member, the sealing performance of the sealing device can be effectively maintained.

[0058] A sealing structure according to one aspect (Aspect 4) of the present disclosure includes a support member having an axial hole, a shaft member that rotates in both directions around a central axis inside the axial hole, and an endless sealing device installed between the support member and the shaft member, the sealing device having a wave shape whose axial position changes periodically according to its circumferential position. According to this aspect, the same effects as those of Aspect 1 are achieved.

[0059] In a specific example (Aspect 5) of Aspect 4, the annular space between the support member and the shaft member is partitioned by the sealing device into a first space and a second space, and the sealing device further includes lubricating oil filled in the first space. In the above aspect, the lubricating oil filled in the first space is held in the space on the inner circumferential side of the portion of the sealing device that is convexly curved toward the second space. In the above configuration, an oil film of lubricating oil is formed between the support member or the shaft member and the sealing device, thereby suppressing wear of the sealing device caused by contact with the support member or the shaft member. [Explanation of symbols]

[0060] 100...sealing structure, 10...support member, 11...shaft hole, 12...mounting groove, 15...step, 20...shaft member, 21...mounting groove, 25...step, 30...sealing device, 31...first part, 32...second part, 40...lubricating oil, 60...annular seal.

Claims

1. An endless sealing device installed between a support member having an axial hole and a shaft member that rotates in both directions around a central axis inside the axial hole, The wave shape is one in which the position in the axial direction changes periodically depending on the position in the circumferential direction. Sealing device.

2. An endless sealing device installed between a support member having an axial hole and a shaft member that rotates in both directions around a central axis inside the axial hole, The first portion and the second portion are located at different circumferential positions, the first portion is a portion that is convexly curved toward a first direction along the central axis, The second portion is a portion that is convexly curved in a second direction opposite to the first direction. Sealing device.

3. An endless sealing device installed between a support member having an axial hole and a shaft member that rotates in both directions around a central axis inside the axial hole, a first portion that is a part in the circumferential direction; a second portion that is a part that is located at a different position in the circumferential direction from the first portion, The position of the first portion in the axial direction is different from the position of the second portion in the axial direction. Sealing device.

4. a support member having an axial hole; a shaft member that rotates in both directions around a central axis inside the shaft hole; an endless sealing device disposed between the support member and the shaft member, The sealing device is The wave shape is one in which the position in the axial direction changes periodically depending on the position in the circumferential direction. Sealed structure.

5. an annular space between the support member and the shaft member is divided into a first space and a second space by the sealing device; Lubricating oil filled in the first space The sealing structure of claim 4 further comprising:

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