阅读说明：本技术 密封装置 (Sealing device ) 是由 谷田昌幸 庄内俊 伊藤卓哉 吉冈贤哉 于 2019-06-25 设计创作，主要内容包括：本发明提供一种能够抑制导电性能下降的密封装置。密封装置(1)具有外侧密封部(2)、内侧密封部(3)、以及容纳在空间(S)中的导电性润滑脂(4)。外侧密封部的外侧弹性体部(20)由导电性的弹性体形成,具有防尘唇(21)、导通唇(22)和衬垫部(23)。内侧密封部(3)在环状的嵌装面(f)上被安装到外侧密封部(2)。内侧密封部(3)的内侧弹性体部(40)由导电性的弹性体形成,并具有润滑脂唇(41)。另外,外侧密封部(2)具有被安装在导通唇(22)的外周侧并将导通唇向内周侧部件按压的弹簧(24)。(The invention provides a sealing device capable of inhibiting the reduction of conductive performance. The sealing device (1) has an outer sealing part (2), an inner sealing part (3), and conductive grease (4) accommodated in a space (S). An outer elastic body section (20) of the outer seal section is formed of an electrically conductive elastic body and has a dust lip (21), a conduction lip (22), and a gasket section (23). The inner seal portion (3) is attached to the outer seal portion (2) on an annular fitting surface (f). The inner elastic body part (40) of the inner sealing part (3) is formed by an electrically conductive elastic body and is provided with a grease lip (41). The outer seal section (2) has a spring (24) that is attached to the outer peripheral side of the conduction lip (22) and presses the conduction lip against the inner peripheral side member.)

1. A sealing device for sealing an annular space around an axis between an inner peripheral side member and an outer peripheral side member, the sealing device characterized by comprising:

an outer seal portion annular about the axis; and

an inner seal portion that is annular about the axis and is mounted on the outer seal portion to form an annular space about the axis with the outer seal portion,

the outer side seal portion includes: an outer reinforcement ring annularly shaped about the axis; and an outer elastomer portion mounted on the outer reinforcing ring and annular about the axis,

the outer elastic body portion is formed of an electrically conductive elastic body and includes: a dust lip slidably contacting the inner peripheral member and extending toward the axis; a conducting lip provided inside the dust lip, slidably contacting the inner peripheral member, and extending toward the axis; and a pad portion that is in contact with the outer peripheral member,

the inner seal portion is attached to the outer elastic body portion of the outer seal portion from an inner peripheral side on a fitting surface that is annular around the axis, and includes: an inner reinforcement ring annularly shaped about the axis; and an inner elastic body portion mounted on the inner reinforcing ring and having a ring shape around the axis,

the inner elastic body portion is formed of an electrically conductive elastic body and has a grease lip that is in slidable contact with the inner peripheral side member and extends toward the axis,

the outer seal portion has a spring that is attached to an outer peripheral side of the conduction lip and presses the conduction lip toward the inner peripheral side.

2. The sealing device of claim 1,

conductive grease is contained in the space formed by the outer seal portion and the inner seal portion.

3. Sealing device according to claim 1 or 2,

at least one of an outer peripheral side protruding portion and an inner peripheral side protruding portion is provided in the sealing device,

the outer peripheral side protruding portion protrudes to an outer peripheral side beyond the fitting surface and is provided on the inner elastic body portion,

the inner peripheral side protrusion protrudes to the inner peripheral side beyond the fitting surface, and is provided on the outer elastic body portion.

4. The sealing device of claim 3,

the outer peripheral side protruding portion is formed on at least a part of the inner elastic body portion,

the inner peripheral side protrusion is formed on at least a part of the pad portion.

5. The sealing device according to any one of claims 1 to 4,

the conduction lip has a conduction lip tip portion that protrudes toward the axis and has a wedge-shaped cross-section.

Technical Field

The present invention relates to a sealing device, and more particularly to a sealing device used in a motor and its vicinity.

Background

In recent years, the electric vehicles have been increasingly driven, and electric vehicles such as electric vehicles and fuel cell vehicles have been increasingly developed. In these electric vehicles, a drive motor is used as a power source, and an induced current generated in the drive motor becomes electromagnetic noise, which may affect a car radio or a wireless device.

Therefore, the following vehicle power transmission device is known: a conductive path for grounding is formed between a shaft driven via a conductive metal brush and a housing, and a leakage current from a drive motor, which causes high-frequency noise, is discharged to the housing via the conductive path by the metal brush (for example, patent document 1).

However, in the vehicle power transmission device as described above, since metal powder is generated due to sliding between the shaft and the metal brush, it is necessary to provide a cover for preventing scattering of the metal powder generated from the metal brush, and it is necessary to secure an installation space of the cover.

In contrast, an electromagnetic noise suppression device is known: in order to save space, an oil seal itself that seals between a through hole in a housing grounded to a vehicle body and a rotating shaft of a motor is formed of a conductive rubber, and the housing and the rotating shaft are electrically conducted via the conductive rubber, thereby releasing electromagnetic noise induced on the rotating shaft to the metal housing (for example, patent document 2).

Prior art documents

Patent document

Patent document 1: japanese patent laid-open publication No. 2015-207534;

patent document 2: japanese patent laid-open No. 2000-244180.

Disclosure of Invention

In such an electromagnetic noise suppression device, although space can be saved, if the device is used for a long time, electromagnetic noise may not be sufficiently emitted to the housing. As described above, the conventional electromagnetic noise suppressing device is required to have a structure that does not cause a decrease in the conductive performance even when used for a long time.

The present invention has been made in view of the above problems, and an object thereof is to provide a sealing device capable of suppressing a decrease in conductive performance.

In order to achieve the above object, the present invention provides a sealing device for sealing an annular space around an axis between an inner peripheral side member and an outer peripheral side member, the sealing device comprising: an outer seal portion annular about the axis; and an inner seal portion annularly shaped about the axis and mounted on the outer seal portion to form an annular space about the axis with the outer seal portion, the outer seal portion comprising: an outer reinforcement ring annularly shaped about the axis; and an outer elastomer portion attached to the outer reinforcement ring and annular around the axis, the outer elastomer portion being formed of a conductive elastomer and including: a dust lip slidably contacting the inner peripheral member and extending toward the axis; a conducting lip provided inside the dust lip, slidably contacting the inner peripheral member, and extending toward the axis; and a gasket portion that is in contact with the outer peripheral member, the inner seal portion being attached to the outer elastic body portion of the outer seal portion from an inner peripheral side on an fitting surface that is annular around the axis, and including: an inner reinforcement ring annularly shaped about the axis; and an inner elastic body portion attached to the inner reinforcing ring and having a ring shape around the axis, the inner elastic body portion being formed of an electrically conductive elastic body and having a grease lip that is in slidable contact with the inner peripheral member and extends toward the axis, the outer sealing portion having a spring that is attached to an outer peripheral side of the conduction lip and presses the conduction lip toward the inner peripheral side.

In the sealing device according to one aspect of the present invention, conductive grease is contained in the space formed by the outer seal portion and the inner seal portion.

In the sealing device according to one aspect of the present invention, at least one of an outer peripheral side protruding portion that protrudes to an outer peripheral side beyond the fitting surface and is provided in the inner elastic body portion and an inner peripheral side protruding portion that protrudes to an inner peripheral side beyond the fitting surface and is provided in the outer elastic body portion is provided.

In the sealing device according to one aspect of the present invention, the outer peripheral side protruding portion is formed at least in part of the inner elastic body portion, and the inner peripheral side protruding portion is formed at least in part of the gasket portion.

In the sealing device according to one aspect of the present invention, the conduction lip has a conduction lip tip portion that protrudes toward the axis and has a wedge-shaped cross section.

According to the sealing device of the present invention, a decrease in the electrical conductivity can be suppressed.

Drawings

Fig. 1 is a sectional view showing a section along an axis of a structure of a sealing device according to an embodiment of the present invention;

fig. 2 is a partially enlarged sectional view showing the structure of a sealing device according to an embodiment of the present invention;

fig. 3 is a partially enlarged sectional view showing the structure of a sealing device according to a modification of the present invention.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Fig. 1 is a sectional view showing a cross section along an axis x of a structure of a sealing device 1 according to an embodiment of the present invention. Fig. 2 is a partially enlarged sectional view showing the structure of the sealing device 1 according to the embodiment of the present invention. For convenience of explanation, the direction of arrow a is set to the outside and the direction of arrow b is set to the inside on the axis x. Here, the outside refers to the atmosphere side where sand, muddy water, or the like exists, and the inside refers to the opposite side to the atmosphere side. In a direction perpendicular to the axis x (hereinafter, also referred to as a radial direction), a direction away from the axis x is an outer peripheral side (arrow c direction), and a direction toward the axis x is an inner peripheral side (arrow d direction).

The sealing device 1 according to the embodiment of the present invention is a device for sealing an annular space around an axis x between an inner peripheral member and an outer peripheral member, not shown. The inner peripheral member is, for example, an output shaft of an electric motor not shown. The outer peripheral member is, for example, a casing, not shown, which houses the electric motor and has a through hole through which an output shaft of the electric motor passes. The inner peripheral member may reciprocate along the axis x.

As shown in fig. 1, the sealing device 1 includes: an outer seal portion 2 annular about the axis x; and an inner seal portion 3 that is annular about the axis x, the inner seal portion 3 being mounted on the outer seal portion 2 so as to form an annular space S about the axis x between the inner seal portion and the outer seal portion 2. The sealing device 1 has conductive grease 4 accommodated in a space S formed by the outer seal portion 2 and the inner seal portion 3.

The outer seal portion 2 includes an outer reinforcing ring 10 annular about the axis x, and an outer elastomer portion 20 annular about the axis x and attached to the outer reinforcing ring 10. The outer seal portion 2 prevents dust such as sand or muddy water from entering from the atmosphere side, and prevents the conductive grease 4 contained in the space S from leaking to the atmosphere side.

The outer elastomer portion 20 is formed of an electrically conductive elastomer, and includes: a dust lip 21 that is in slidable contact with the inner peripheral member and extends toward the axis x; a conducting lip 22 provided inside the dust lip 21, slidably contacting the inner peripheral member, and extending toward the axis x; and a pad portion 23 that contacts the outer peripheral member.

The inner seal portion 3 is attached to the outer elastic body portion 20 of the outer seal portion 2 from the inner peripheral side on an insertion surface f annular about the axis x, and includes an inner reinforcing ring 30 annular about the axis x and an inner elastic body portion 40 annular about the axis x attached to the inner reinforcing ring 30. The inner seal portion 3 prevents grease or the like from entering from the inside in the use state of the sealing device 1, and prevents the conductive grease 4 accommodated in the space S from leaking to the inside. The fitting surface f is a surface formed between portions where the outer seal portion 2 and the inner seal portion 3 contact each other in order to fit the outer seal portion 2 and the inner seal portion 3 into each other in a state where the inner seal portion 3 is attached to the outer seal portion 2. The inner elastic body portion 40 is formed of an electrically conductive elastic body, and has a grease lip 41, and the grease lip 41 is in contact with the inner peripheral member so as to be slidable, and extends toward the axis x. The outer seal portion 2 has a spring 24 attached to the outer peripheral side of the conduction lip 22 and pressing the conduction lip 22 against the inner peripheral side member. The structure of the sealing device 1 will be specifically described below.

In the outer seal portion 2, as shown in fig. 1, the outer reinforcement ring 10 is an annular metal member centered or substantially centered on the axis x, and has an L-shaped or substantially L-shaped cross section (hereinafter also simply referred to as "cross section") along the axis x. The outer reinforcement ring 10 includes, for example, a cylindrical portion 11 and a disk portion 12, the cylindrical portion 11 being a cylindrical or substantially cylindrical portion extending in the axis x direction, and the disk portion 12 being a hollow disk-shaped portion extending from an outer end (in the arrow a direction) of the cylindrical portion 11 to an inner circumferential side (in the arrow d direction). The cylindrical portion 11 is formed so that the sealing device 1 can be fitted to the inner peripheral surface of a through hole formed in an outer peripheral member, not shown, and may be fitted by directly contacting the inner peripheral surface of the through hole, or may be fitted by contacting the inner peripheral surface of the through hole via a portion of the outer elastic body portion 20.

As shown in fig. 1, the outer elastomer portion 20 is attached to the outer reinforcement ring 10, and in the present embodiment, is formed integrally with the outer reinforcement ring 10 so as to cover the entire outer reinforcement ring 10. As described above, the outer elastic body portion 20 includes the dust lip 21, the conduction lip 22 provided inside the dust lip 21, and the pad portion 23. The outer elastic body portion 20 has an annular outer lip waist portion 25 and an outer cover portion 26. The outer lip waist portion 25 is a portion located in the vicinity of an end portion on the inner circumferential side of the disc portion 12 of the outer reinforcement ring 10. The outer cover portion 26 is a portion that is attached to the disc portion 12 from the outside and the inside between the outer lip waist portion 25 and the pad portion 23.

The dust lip 21 extends obliquely outward from the outer lip waist portion 25 toward the axis x, and has a shape that decreases in diameter as it extends outward. The dust-lip tip portion 21a, which is the tip portion of the dust lip 21, is formed so as to be in contact with the outer-peripheral-side surface of the inner-peripheral-side member so as to be slidable with respect to the inner-peripheral-side member in a use state (hereinafter, also simply referred to as "use state") in which the seal device 1 is mounted in the space between the inner-peripheral-side member and the outer-peripheral-side member.

The conducting lip 22 is located inside the dust lip 21, extends obliquely inward toward the axis x from the outer lip waist portion 25, and has a shape that decreases in diameter as it goes inward. Further, a conduction lip tip portion 22a as a tip portion of the conduction lip 22 is an annular portion having a wedge-shaped cross section and projecting toward the inner peripheral side. The conducting lip tip portion 22a is formed to be in contact with the outer peripheral surface of the inner peripheral member so that the inner peripheral member is slidable in the use state of the sealing device 1. Further, the conducting lip 22 is provided with a recessed portion 22b at a position on the outer peripheral side opposite to the conducting lip tip portion 22a, and the recessed portion 22b is a portion recessed toward the inner peripheral side.

The pad 23 is attached to the cylindrical portion 11 so as to surround the cylindrical portion 11 of the outer reinforcement ring 10 from the outer circumferential side and the inner circumferential side, and includes an outer circumferential pad 23a and an inner circumferential pad 23b, the outer circumferential pad 23a covering the cylindrical portion 11 from the outer circumferential side, and the inner circumferential pad 23b covering the cylindrical portion 11 from the inner circumferential side. The radial thickness of the outer peripheral side gasket portion 23a is set so that, when the sealing device 1 is press-fitted into the inner peripheral side surface (through hole) of the outer peripheral side member, the through hole and the cylindrical portion 11 of the outer reinforcing ring 10 are compressed in the radial direction, and a force directed in the radial direction, that is, a fitting force, of a predetermined magnitude is generated. The radial thickness of the inner peripheral side pad portion 23b is set so that, in a state where the inner seal portion 3 is fitted to the outer seal portion 2, that is, when the inner seal portion 3 is press-fitted into the inner peripheral side pad portion 23b, the outer reinforcing ring 10 is compressed in the radial direction between the cylindrical portion 11 and the inner seal portion 3 (fitting surface f), and a force directed in the radial direction, that is, a fitting force, of a predetermined magnitude is generated.

The spring 24 is fitted in a recess 22b formed on the conduction lip 22. The spring 24 is, for example, a metal spiral spring member, and presses the conduction lip tip portion 22a in the direction toward the axis x, and applies a predetermined amount of tension to the conduction lip tip portion 22a relative to the inner peripheral member so that the conduction lip tip portion 22a follows the displacement of the inner peripheral member. The spring 24 is not limited to being made of metal, and may be made of various other materials such as resin.

In the inner seal portion 3, as shown in fig. 1, the inner reinforcement ring 30 is an annular metal member centered or substantially centered on the axis x, and has an L-shaped or substantially L-shaped cross section. The inner reinforcement ring 30 includes, for example, a cylindrical portion 31 and a disk portion 32, the cylindrical portion 31 being a cylindrical or substantially cylindrical portion extending in the axis x direction, and the disk portion 32 being a hollow disk-shaped portion extending from an inner end of the cylindrical portion 31 to the inner circumferential side. As described above, the cylindrical portion 31 is formed such that the inner seal portion 3 is fitted and fixed to the outer seal portion 2, and the outer peripheral surface 31a of the cylindrical portion 31 can be fitted to the inner peripheral surface 23c of the inner peripheral pad portion 23b of the outer elastic body portion 20 of the outer seal portion 2. The outer peripheral surface 31a of the cylindrical portion 31 of the inner reinforcing ring 30 and the inner peripheral surface 23c of the inner peripheral side pad portion 23b are in contact with each other, and an engagement surface f is formed between the outer peripheral surface 31a and the inner peripheral surface 23 c. The outer circumferential surface 31a of the cylindrical portion 31 of the inner reinforcing ring 30 has a diameter set to compress the inner circumferential pad portion 23b of the outer elastic body portion 20 in the radial direction between the inner circumferential pad portion and the cylindrical portion 11 of the outer reinforcing ring 10.

As shown in fig. 1, the inner elastic body portion 40 is attached to the inner reinforcement ring 30, and in the present embodiment, is formed integrally with the inner reinforcement ring 30 so as to partially cover the inner reinforcement ring 30 from the inner side and the inner peripheral side. As described above, the inner elastic body portion 40 has the grease lip 41. The inner elastic body portion 40 has an annular inner labial waist portion 42 and an inner cover portion 43. The inner lip waist portion 42 is a portion located in the vicinity of an end portion on the inner circumferential side of the disc portion 32 of the inner reinforcing ring 30. The inner cover portion 43 covers the disc portion 32 from the inside, and extends to a connection portion between the disc portion 32 and the cylindrical portion 31 or a vicinity of the connection portion.

The grease lip 41 extends obliquely inward toward the axis x from the inner peripheral surface of the inner lip waist portion 42, and has a shape that decreases in diameter as it goes inward. The grease lip tip 41a, which is the tip of the grease lip 41, is formed so as to be in contact with the outer peripheral surface of the inner peripheral member in a manner such that the inner peripheral member is slidable in the use state of the sealing device 1.

As shown in fig. 1 and 2, the inner seal portion 3 includes an outer peripheral side protruding portion 44, and the outer peripheral side protruding portion 44 protrudes to the outer peripheral side beyond the fitting surface f and is provided in the inner elastic body portion 40. The outer peripheral side protruding portion 44 is formed on at least a part of the inner elastic body portion 40. Specifically, as shown in fig. 2, the outer peripheral side protruding portion 44 is an annular portion having a wedge-shaped cross section protruding to the outer peripheral side from an end surface (outer peripheral surface 43a) on the outer peripheral side of the inner cover portion 43 of the inner elastic body portion 40. The outer peripheral side protruding portion 44 extends in a continuous ring shape around the axis x or substantially around the axis x, and protrudes to the outer peripheral side than the outer peripheral surface 31a of the cylindrical portion 31 of the inner reinforcing ring 30. In the present embodiment, the outer peripheral surface 43a of the inner cover portion 43 is formed to be coplanar or substantially coplanar with the outer peripheral surface 31a of the cylindrical portion 31 of the inner reinforcement ring 30, and the entire or substantially entire outer peripheral side protruding portion 44 protrudes to the outer peripheral side more than the outer peripheral surface 31a of the cylindrical portion 31. That is, the entire or substantially the entire outer peripheral side protruding portion 44 protrudes further toward the outer peripheral side than the fitting surface f. The outer peripheral side protruding portion 44 may be formed such that at least the distal end 44a of the outer peripheral side protruding portion 44 protrudes outward from the fitting surface f.

The outer peripheral side protruding portion 44 may be formed continuously and annularly around the axis x as described above, may be formed intermittently and annularly around the axis x, or may be formed as at least one protrusion. Specifically, the outer peripheral side protruding portion 44 may be formed by a plurality of arc-shaped portions having a wedge-shaped cross section, which are formed at equal angular intervals about the axis x and protrude toward the outer peripheral side, on a circumference centered or substantially centered on the axis x, or may be formed by one of such arc-shaped portions. The outer peripheral side protruding portion 44 may be formed of a plurality of tapered portions that are formed at equal angular intervals around the axis x and protrude toward the outer peripheral side, or may be formed of one of such tapered portions. The shape of the outer peripheral side protruding portion 44 is not limited to this, and may be another shape protruding to the outer peripheral side as described above. When the inner seal portion 3 is attached to the outer seal portion 2, the outer peripheral side protruding portion 44 strongly bites into the inner peripheral side pad portion 23b from the inner peripheral side.

The inner cover portion 43 of the inner elastic body portion 40 may be formed to cover the outer circumferential surface 31a of the cylindrical portion 31 of the inner reinforcing ring 30. In this case, the inner sealing portion 3 is fitted to the inner peripheral pad portion 23b of the outer sealing portion 2 on the outer peripheral surface 43a of the inner cover portion 43, and the outer peripheral surface 43a of the inner cover portion 43 forms a fitting surface f. In this case, the outer peripheral protrusion 44 may be formed in an outer peripheral portion of the cylindrical portion 31.

As the conductive elastomer of the outer elastomer portion 20 and the inner elastomer portion 40, for example, there is conductive rubber containing a conductive filler such as carbon black particles or metal powder. Such conductive rubbers have a low electrical resistance.

Examples of the metal material of the outer reinforcement ring 10 and the inner reinforcement ring 30 include stainless steel and SPCC (cold rolled steel). The outer reinforcement ring 10 and the inner reinforcement ring 30 are manufactured by, for example, press working or forging, and the outer elastomer portions 20 and the inner elastomer portions 40 are formed by cross-linking (vulcanization) forming using a forming die. In the cross-linking molding, the outer reinforcement ring 10 and the inner reinforcement ring 30 are disposed in a molding die, the outer elastomer portion 20 and the inner elastomer portion 40 are bonded to the outer reinforcement ring 10 and the inner reinforcement ring 30 by cross-linking bonding, and the outer elastomer portion 20 and the inner elastomer portion 40 are integrally molded with the outer reinforcement ring 10 and the inner reinforcement ring 30, respectively.

The sealing device 1 is assembled by attaching the inner seal portion 3 to the outer seal portion 2 from the inner side and the inner peripheral side. In the sealing device 1, a space S that closes the outer, inner, and outer peripheral sides is formed between the outer sealing portion 2 and the inner sealing portion 3, and the conductive grease 4 is contained in the space S. Therefore, even when the conduction lip 22 is pressed against the inner peripheral member by the spring 24 in the use state of the sealing device 1, stable lubrication between the conduction lip tip portion 22a and the outer peripheral surface of the inner peripheral member can be ensured. Further, the state in which the conductive grease 4 is applied to the contact portions of the dust lip 21 and the grease lip 41 can be maintained, and stable lubrication between the dust lip 21 and the grease lip 41 and the inner peripheral member can be ensured.

In the sealing device 1, as described above, the outer peripheral side protruding portion 44 bites into the inner peripheral side gasket portion 23b from the inner peripheral side, and therefore the outer peripheral side protruding portion 44 and the inner peripheral side gasket portion 23b are in close contact with each other, and therefore a stable conduction path with small resistance is formed between the inner elastic body portion 40 of the inner sealing portion 3 and the outer elastic body portion 20 of the outer sealing portion 2.

In the use state of the sealing device 1, the dust lip 21 and the conduction lip 22 are in contact with the outer peripheral surface of the inner peripheral member. Therefore, the dust lip 21 and the conduction lip 22 can prevent dust such as sand or muddy water from entering from the atmosphere side, prevent the conductive grease 4 contained in the space S from leaking to the atmosphere side, and form a conduction path from the inner peripheral side member to the outer elastic body portion 20.

In the use state of the sealing device 1, the grease lip 41 is in contact with the outer peripheral surface of the inner peripheral member. Therefore, the grease lip 41 can prevent lubricant or the like from entering from the inside, prevent the conductive grease 4 contained in the space S from leaking to the inside, and form a conduction path from the inner peripheral member to the inner elastic body portion 40.

Further, in the sealing device 1, the conduction lip 22 is pressed against the outer peripheral surface of the inner peripheral member by the tension of the spring 24, so that the conduction state, which is the contact state of the conduction lip 22 with respect to the outer peripheral surface of the inner peripheral member, can be stabilized, and the generation of noise can be stably reduced. Further, even after the sealing device 1 is used for a long time, the state in which the conduction lip 22 is strongly pressed against the outer peripheral surface of the inner peripheral member can be maintained by the tension of the spring 24, and therefore, the conduction state from the start of use can be maintained, the generation of noise can be stably suppressed, and the decrease in the electrical conductivity can be suppressed.

The sealing device 1 further includes an outer elastic body portion 20 and an inner elastic body portion 40 formed of an electrically conductive elastic body. Therefore, in the use state of the sealing device 1, the conduction between the inner peripheral member and the outer peripheral member can be ensured via the outer elastic body portion 20 and the inner elastic body portion 40. Specifically, in the use state of the sealing device 1, the following three conduction paths can be ensured. The first conduction path is a path connecting the inner peripheral side member to the outer peripheral side member via the dust lip 21, the outer lip waist portion 25, the outer cover portion 26, and the pad portion 23. The second conduction path is a path connecting the inner peripheral side member to the outer peripheral side member via the conduction lip 22, the outer lip waist portion 25, the outer cover portion 26, and the pad portion 23. The third conduction path is a path connecting the inner peripheral member to the outer peripheral member via the grease lip 41, the inner lip waist portion 42, the inner cover portion 43, the outer peripheral protruding portion 44, and the pad portion 23.

Therefore, the leakage current generated in the electric motor or the like can be discharged from the inner peripheral member (output shaft) to the outer peripheral member (housing) through the first conductive path, the second conductive path, and the third conductive path, and the generation of noise can be suppressed. In particular, in the third conductive path, since the outer peripheral side protruding portion 44 is strongly bitten into the pad portion 23 from the inner peripheral side, the contact surface pressure between the outer peripheral side protruding portion 44 and the pad portion 23 can be increased, and the actual contact area between the outer peripheral side protruding portion 44 and the pad portion 23 can be increased. This can improve the electrical conductivity.

Although the sealing device 1 according to the embodiment of the present invention has been described above, the sealing device according to the present invention is not limited to the sealing device 1 described above, and includes all embodiments included in the concept of the present invention and the claims. In addition, in order to achieve at least part of the above-described problems and effects, the respective structures may be selectively combined as appropriate. For example, the shape, material, arrangement, size, and the like of each component in the above embodiments may be appropriately changed according to a specific use mode of the present invention.

For example, the sealing device 1 may have an inner circumferential side protruding portion 27 instead of the outer circumferential side protruding portion 44 or together with the outer circumferential side protruding portion 44, and the inner circumferential side protruding portion 27 may be provided on the cushion portion 23 so as to protrude to the inner circumferential side beyond the fitting surface f. The inner peripheral side protruding portion 27 has the same shape as the outer peripheral side protruding portion 44, and is formed in at least a part of the inner peripheral side pad portion 23 b.

For example, as shown in fig. 3, the inner peripheral side protrusion 27 extends in a continuous loop around the axis x or substantially around the axis x, and has a wedge-shaped cross section protruding inward from the inner peripheral surface 23c of the inner peripheral side pad portion 23b of the outer elastic body portion 20. The entire or substantially the entire inner peripheral side protrusion 27 protrudes further toward the inner peripheral side than the inner peripheral surface 23c of the inner peripheral side pad portion 23 b. That is, the entire or substantially the entire inner peripheral side protruding portion 27 protrudes further toward the inner peripheral side than the fitting surface f. The inner peripheral side protruding portion 27 is formed at a position biting into the inner elastic body portion 40 of the inner seal portion 3 from the outer peripheral side. As in the case of the outer-peripheral-side protrusion 44, at least the distal end 27a of the inner-peripheral-side protrusion 27 may protrude inward from the fitting surface f. The inner peripheral side protrusion 27 may be formed continuously and continuously in a ring shape around the axis x as described above, may be formed partially in a ring shape around the axis x, or may be formed as at least one protrusion. When the inner seal portion 3 is attached to the outer seal portion 2, the inner peripheral side protrusion 27 strongly bites into the inner cover portion 43 of the inner elastic body portion 40 from the outer peripheral side.

[ description of symbols ]

1 sealing device, 2 outer sealing portion, 3 inner sealing portion, 4 conductive grease, 10 outer reinforcing ring, 11 cylindrical portion, 12 disc portion, 20 outer elastic body portion, 21 dust lip, 21a dust lip tip portion, 22 conducting lip, 22a conducting lip tip portion, 22b recess, 23 pad portion, 23a outer peripheral side pad portion, 23b inner peripheral side pad portion, 23c inner peripheral surface, 24 spring, 25 outer lip waist portion, 26 outer cover portion, 27 inner peripheral side protruding portion, 27a tip portion, 30 inner reinforcing ring, 31 cylindrical portion, 31a outer peripheral surface, 32 disc portion, 40 inner elastic body portion, 41 grease lip, 41a grease lip tip portion, 42 inner lip waist portion, 43 inner cover portion, 43a outer peripheral surface, 44 outer peripheral side protruding portion, 44a tip portion, f fitting surface, S space, x axis.