Sealing device

Abstract

This sealing device (100) seals a gap (320) between an outer circumferential surface (210) of a rotating shaft (200) and an inner circumferential surface (310) of a shaft hole (301) in a housing (300) in which the rotating shaft (200) is inserted into the shaft hole (301), the sealing device (100) being disposed in the gap (320). The sealing device (100) comprises: a first lip portion (23); a second lip portion disposed on an inner side (330) further inward in the housing (300) than the first lip portion (23); and a metal ring (70) that holds the second lip portion. The second lip portion is a conductive lip (50) made of a conductive material. The metal ring (70) has: a contact portion (70a) that contacts the housing (300); and an inward extending portion (70b) that extends radially inward from the contact portion (70a) and holds the conductive lip (50).

Description

sealing device

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

[0002] 2. Description of the Related Art A sealing device is known that is disposed in a gap between an outer peripheral surface of a rotating shaft and an inner peripheral surface of a shaft hole in a housing having the shaft hole into which the rotating shaft is inserted.

[0003] As shown in FIG. 6 , the sealing device (sealing device 1000) can be incorporated into a reducer 1900 for an electric vehicle (EV) or a fuel cell vehicle (FCV), for example. In the example of FIG. 6 , the reducer 1900 includes a housing 1300, a first rotating shaft 1201, a second rotating shaft 1202, and a third rotating shaft 1203 provided in the housing 1300, and a plurality of bearings 1400 provided in the housing 1300 and supporting the first rotating shaft 1201, the second rotating shaft 1202, and the third rotating shaft 1203, respectively. Electric power from a battery 1500 is supplied to an electric motor 1700 via an inverter 1600, and the electric motor 1700 is driven to rotate the first rotating shaft 1201, which is the output shaft of the electric motor 1700. The first rotating shaft 1201, the second rotating shaft 1202, and the third rotating shaft 1203 are connected in this order via a gear 1220. The rotation of the first rotating shaft 1201 is transmitted from the first rotating shaft 1201 to the second rotating shaft 1202, and further transmitted from the second rotating shaft 1202 to the third rotating shaft 1203. In other words, the rotation of the first rotating shaft 1201 is transmitted to the third rotating shaft 1203 at a desired reduction ratio. The third rotating shaft 1203 is provided with a wheel 1800.

[0004] However, in a mechanism including rotating shafts (first rotating shaft 1201, second rotating shaft 1202, and third rotating shaft 1203) that are rotationally driven by electric motor 1700, as in the example of Figure 6, induced currents generated by electric motor 1700 can cause AM radio electromagnetic noise from the rotating shafts, and sparks can occur in bearing 1400, causing electrolytic corrosion in bearing 1400. To solve these problems, it is desirable to ensure electrical continuity between the rotating shafts and housing 1300, that is, to ground the rotating shafts to housing 1300. Existing technology for this purpose includes earth brushes, but these have problems such as the need to secure a dedicated space and the generation of brush wear powder.

[0005] A sealing device having a conductive lip is one technique for solving the above-mentioned problems. The sealing device (seal ring in the same document) of Patent Document 1 includes a seal body having a lip portion (seal lip in the same document) and a conductive lip (front seal in the same document) provided on the atmosphere-side surface of the seal body.

[0006] Japanese Patent Application Laid-Open No. 2014-142065

[0007] However, according to the investigations of the present inventors, there is still room for improvement in the technology of Patent Document 1 in terms of ensuring electrical continuity by the conductive lip more reliably.

[0008] The present invention has been made in view of the above-mentioned problems, and aims to provide a sealing device that can more reliably ensure electrical continuity by means of a conductive lip.

[0009] According to the present invention, there is provided a sealing device that is arranged in a gap between the outer peripheral surface of a rotating shaft and the inner peripheral surface of a shaft hole in a housing having a shaft hole into which the rotating shaft is inserted, and that seals the gap, the sealing device comprising: a first lip portion; a second lip portion that is arranged more inward than the first lip portion within the housing; and a metal ring that holds the second lip portion, wherein the second lip portion is a conductive lip made of a conductive material, and the metal ring has an abutment portion that abuts against the housing and an inward extension portion that extends radially inward from the abutment portion and holds the conductive lip.

[0010] According to the present invention, it is possible to more reliably ensure electrical continuity by the conductive lip.

[0011]

[0023] Fig. 3(a) is a cross-sectional end view showing a first unit of the sealing device according to the first embodiment, showing a state before the rotating shaft is inserted therein, and Fig. 3(b) is a cross-sectional end view showing a second unit of the sealing device according to the first embodiment, showing a state before the rotating shaft is inserted therein.

[0024] Fig. 3(b) is an exploded cross-sectional end view for explaining a manufacturing process of the second unit of the sealing device according to the first embodiment.

[0025] Fig. 3(a) is a cross-sectional end view showing a sealing device according to the second embodiment, showing a cross-sectional end view along the axis of the rotating shaft.

[0026] Fig. 3(b) is a schematic view for explaining problems with a general sealing device.

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same components are denoted by the same reference numerals, and the description thereof will be omitted where appropriate.

[0013] First Embodiment First, a first embodiment will be described with reference to FIGS. 1 to 4 . The sealing device 100 is disposed in the gap 320 such that the central axis AX of the sealing device 100 coincides with the axis of the rotating shaft 200. In the following description, a direction perpendicular to the central axis AX will be referred to as the radial direction. Furthermore, within the radial direction, a direction away from the central axis AX will be referred to as the radially outer direction, and a direction approaching the central axis AX will be referred to as the radially inner direction. Furthermore, a direction revolving around the central axis AX will be referred to as the circumferential direction. Furthermore, a direction along the central axis AX may be simply referred to as the axial direction. Furthermore, one side (the right side in FIGS. 1 and 2 ) of the direction along the central axis AX is the inner side (inside of the machine) of the mechanism in which the sealing device 100 is provided, and this direction will be referred to as the inner side 330. The other side (left side in FIGS. 1 and 2) in the direction along the central axis AX is the external side (atmospheric side) of the mechanism in which the sealing device 100 is provided, and this direction is referred to as the external side 340.

[0014] 1 or 2 , a sealing device 100 according to this embodiment is disposed in a gap 320 between an outer peripheral surface 210 of a rotating shaft 200 and an inner peripheral surface 310 of a shaft hole 301 in a housing 300 having the shaft hole 301 into which the rotating shaft 200 is inserted, to seal the gap 320. The sealing device 100 includes a first lip portion 23, a second lip portion disposed inside the housing 300 on an inner side 330 of the first lip portion 23, and a metal ring 70 that holds the second lip portion. The second lip portion is a conductive lip 50 made of a conductive material. The metal ring 70 has an abutting portion 70a that abuts against the housing 300 and an inward extending portion 70b that extends radially inward from the abutting portion 70a and holds the conductive lip 50.

[0015] According to the sealing device 100 of this embodiment, when the sealing device 100 is assembled to the housing 300 and seals the gap 320 of the axial bore 301 of the housing 300, the metal ring 70 and the conductive lip 50 each form a portion of the conductive path between the housing 300 and the rotating shaft 200. This ensures electrical continuity between the rotating shaft 200 and the housing 300 through the metal ring 70 and the conductive lip 50, i.e., the rotating shaft can be grounded to the housing 300. This makes it possible to suppress AM radio electromagnetic noise from the rotating shaft and electrolytic corrosion of bearings. Because the sealing device 100 can replace existing sealing devices, a dedicated space for an earth brush is not required, and brush wear powder is also prevented. Furthermore, unlike technologies that ensure electrical continuity between the rotating shaft 200 and the housing 300 using a conductive lip alone, the conductive lip 50 and the metal ring 70, which is a metal member, ensure electrical continuity between the rotating shaft 200 and the housing 300, thereby reducing electrical resistance in the conductive path from the rotating shaft 200 to the housing 300. Furthermore, by arranging the conductive lip 50 inside the housing 300 on the inner side 330 of the contact point between the first lip portion 23 and the rotating shaft 200, that is, by arranging the conductive lip 50 on the inner side 330 of the point sealed by the first lip portion 23, it becomes possible to suppress the influence of foreign matter on the conductive lip 50. Therefore, it is possible to more reliably ensure electrical continuity by the conductive lip 50.

[0016] In this embodiment, the first lip portion 23 is a dust lip. The sealing device 100 combines the first lip portion 23, which is a dust lip, with the conductive lip 50, thereby achieving both dust sealing performance and electrical conductivity while reducing the number of parts and installation space. The conductive lip 50 is positioned on the inner side 330 of the contact point between the first lip portion 23, which is a dust lip, and the rotating shaft 200, thereby providing electrical conductivity without impairing dust sealing performance. The sealing device 100 uses the first lip portion 23 and the conductive lip 50 to prevent foreign matter from entering the inner side 330 from the outer side 340. In particular, electrical conductivity can be ensured with a small number of parts, even in a water-exposed environment where an earth brush would be difficult to use. A separate oil seal (with an oil lip) may be positioned on the inner side 330 of the conductive lip 50.

[0017] The present embodiment will be described in more detail below.

[0018] An example of a mechanism in which the sealing device 100 is disposed (mounted) is a reducer for an electric vehicle (EV) or a fuel cell vehicle (FCV), and the mechanism includes a housing 300 made of a metal material. The housing 300 has a shaft hole 301 into which the rotating shaft 200 is inserted. Note that, of the sealing device 100 and the rotating shaft 200, the sealing device 100 is usually inserted and fixed into the shaft hole 301 first, and then the rotating shaft 200 is inserted.

[0019] In this embodiment, the sealing device 100 is configured to include a first unit 110 having a first lip portion 23 and a second unit 120 having a conductive lip 50 .

[0020] The first unit 110 includes a seal body 10. The seal body 10 includes a core 30 made of a metal material and a seal body component 20 made of an elastic body and integrated with the core 30. The seal body component 20 includes a first lip portion 23.

[0021] The seal body constituent member 20 is formed in an annular shape centered on the central axis AX. The seal body constituent member 20 has, for example, a body abutment portion 21 formed in a cylindrical shape concentric with the central axis AX, and a body inward extension portion 22 extending radially inward in the form of an inner flange from one end (an end on the outer side 340) of the body abutment portion 21 in the axial direction. The first lip portion 23 extends obliquely from the radially inner end of the body inward extension portion 22 radially inward and toward the outer side 340 (the left side in FIG. 2 ).

[0022] The seal body component 20 has an outward extension portion 25 that extends from the outer side 340 surface of the body inward extension portion 22 toward the outer side 340. The outward extension portion 25 is disposed radially outward of the first lip portion 23. A slinger 90 is fixed to the rotating shaft 200. The slinger 90 rotates as the rotating shaft 200 rotates. The slinger 90 is formed, for example, in the shape of a stepped flange that shifts radially outward in stages toward the inner side 330. The outward extension portion 25 extends toward the inside of the gap between the slinger 90 and the outer peripheral surface 210 of the rotating shaft 200.

[0023] The seal body constituent member 20 is formed into a three-dimensional shape that corresponds to the movement trajectory of the cut end surface shape of the seal body constituent member 20 shown in Figure 2 when the cut end surface shape is rotated once around the central axis AX. A portion of the outer peripheral surface of the body abutment portion 21 forms a contact surface 21a that is pressed circumferentially against the inner peripheral surface 310 of the shaft hole 301. The first lip portion 23 is pressed circumferentially against the outer peripheral surface 210 of the rotating shaft 200, and slides against the outer peripheral surface 210 when the rotating shaft 200 rotates. Sealing performance is ensured by the pressed contact points between the contact surface 21a and the inner peripheral surface 310 and the pressed contact points between the first lip portion 23 and the outer peripheral surface 210.

[0024] Because the first lip portion 23 does not require electrical conductivity, a general sealing rubber material can be used as the material for the seal body constituent member 20. Examples of such elastic materials include synthetic rubbers such as nitrile rubber (NBR), hydrogenated nitrile rubber (H-NBR), acrylic rubber (ACM), and fluororubber (FKM).

[0025] The entire seal body constituent member 20 is molded as a single unit. More specifically, the seal body constituent member 20 is molded as a single unit together with the core metal 30. For example, the core metal 30 is placed in a mold (not shown), an uncrosslinked rubber material is injected, and then the cavity of the mold is heated and pressurized to crosslink the rubber material, thereby obtaining the seal body 10 in which the seal body constituent member 20 and the core metal 30 are molded as a single unit.

[0026] Examples of the metal material that constitutes the core 30 include stainless steel (SUS) and cold rolled steel (SPCC). The core 30 can be formed by press working or forging.

[0027] The core 30 includes, for example, a cylindrical portion 31 formed concentrically with the central axis AX, and a core inward extending portion 32 extending radially inward in the form of an inner flange from one end (the end of the outer side 340) of the core 30 in the axial direction. The core 31 of the core 30 is embedded in the main body abutting portion 21. However, a portion of the cylindrical portion 31 may be exposed from the main body abutting portion 21 (from the seal main body constituent member 20). The core inward extending portion 32 is embedded in the main body inward extending portion 22. The core inward extending portion 32 may be formed in the form of a flat flange, or may be partially bent to conform to the shape of the seal main body constituent member 20, as shown in FIG. 2. The core 30 is formed in a three-dimensional shape corresponding to the movement trajectory of the cut end surface shape of the core 30 shown in FIG. 2 when the cut end surface shape is rotated once around the central axis AX.

[0028] The first unit 110 is composed of the above-mentioned seal body 10. On the other hand, the second unit 120 is composed of a metal ring 70 and a conductive lip 50.

[0029] The metal ring 70 is configured with a first metal ring 71 and a second metal ring 72. The first metal ring 71 has a first cylindrical portion 71a and a first inward extending portion 71b extending radially inward from the first cylindrical portion 71a. The second metal ring 72 has a second cylindrical portion 72a arranged along the inner circumferential surface of the first cylindrical portion 71a and a second inward extending portion 72b extending radially inward from the second cylindrical portion 72a and arranged along the first inward extending portion 71b. The first cylindrical portion 71a and the second cylindrical portion 72a form a contact portion 70a. The first inward extending portion 71b and the second inward extending portion 72b form an inward extending portion 70b. The conductive lip 50 is sandwiched between the first inward extending portion 71b and the second inward extending portion 72b, and is thereby held by the inward extending portion 70b of the metal ring 70. In this way, the conductive lip 50 is held by being sandwiched between two metal rings (the first metal ring 71 and the second metal ring 72), so a structure in which the conductive lip 50 is held more stably can be realized.

[0030] The second inward extending portion 72b is positioned closer to the inner side 330 within the housing 300 than the first inward extending portion 71b. The inner circumferential end of the second inward extending portion 72b (the inner circumferential end 72c of the second metal ring 72) is positioned radially outward than the inner circumferential end of the first inward extending portion 71b (the inner circumferential end 71c of the first metal ring 71). As a result, the portion of the conductive lip 50 that extends radially inward beyond the inward extending portion 70b is bent toward the inner side 330 within the housing 300.

[0031] The first cylindrical portion 71a is formed, for example, in a cylindrical shape concentric with the central axis AX. The first inward extending portion 71b extends radially inward from one axial end (the end on the outer side 340) of the first cylindrical portion 71a in the shape of an inner flange. The first cylindrical portion 71a is formed, for example, in a flat plate shape perpendicular to the central axis AX and in a donut shape. The first metal ring 71 is formed in a three-dimensional shape corresponding to the movement trajectory of the cut end surface shape of the first metal ring 71 shown in FIG. 2 when the cut end surface shape is rotated once around the central axis AX. The outer peripheral surface of the first cylindrical portion 71a is pressed against the inner peripheral surface 310 of the axial hole 301 in a circular manner.

[0032] The second cylindrical portion 72a is formed, for example, in a cylindrical shape concentric with the central axis AX. The second inward extending portion 72b extends radially inward from one axial end (the end on the outer side 340) of the second cylindrical portion 72a in the axial direction in the form of an inner flange. The second cylindrical portion 72a is formed, for example, in a flat plate shape perpendicular to the central axis AX and in a donut shape. The second metal ring 72 is formed in a three-dimensional shape corresponding to the movement trajectory of the cut end surface shape of the second metal ring 72 shown in FIG. 2 when the cut end surface shape is rotated once around the central axis AX. The inner peripheral surface of the first cylindrical portion 71a is pressed against the outer peripheral surface of the second cylindrical portion 72a in a circumferential manner.

[0033] Examples of materials for the first metal ring 71 and the second metal ring 72 include stainless steel (SUS) or cold-rolled steel (SPCC). The first metal ring 71 and the second metal ring 72 can be formed by press working or forging.

[0034] The conductive lip 50 is formed in a doughnut shape centered on the central axis AX. The conductive lip 50 is formed in a three-dimensional shape corresponding to the movement trajectory of the cut end surface shape of the conductive lip 50 shown in FIG. 2 when the cut end surface shape is rotated once around the central axis AX. In this embodiment, the tip end (the radially inner end) of the conductive lip 50 contacts the outer peripheral surface 210 of the rotating shaft 200 in a circumferential manner, thereby ensuring electrical conduction between the rotating shaft 200 and the conductive lip 50. Note that the tip end of the conductive lip 50 slides against the outer peripheral surface 210 when the rotating shaft 200 rotates.

[0035] In this embodiment, the conductive lip 50 is not required to have sealing properties. Therefore, a material specialized for conductivity can be used as the material for the conductive lip 50, such as conductive rubber or conductive resin. A preferred example of the material for the conductive lip 50 is conductive PTFE (fluororesin: Polytetrafluoroethylene).

[0036] The outer peripheral edge of the conductive lip 50 is located radially inward of the inner peripheral surface of the first cylindrical portion 71 a, and therefore (unlike the conductive lip (front seal) in Patent Document 1), the outer peripheral edge of the conductive lip 50 does not reach the inner peripheral surface 310 (is spaced apart from the inner peripheral surface 310).

[0037] The sealing device 100 is configured as described above.

[0038] The first unit 110 and the second unit 120 of the sealing device 100 are each fixed to the housing 300. The second unit 120 is fixed to the housing 300 by being inserted into the axial hole 301 so that the outer peripheral surface of the abutting portion 70a, i.e., the outer peripheral surface of the first metal ring 71, is pressed against and fixed to the inner peripheral surface 310. The first unit 110 is fixed to the housing 300 by being inserted into the axial hole 301 so that the contact surface 21a is pressed against and fixed to the inner peripheral surface 310. As shown in FIG. 2 , the second unit 120 is disposed closer to the inner side 330 than the first unit 110. For example, the first unit 110 and the second unit 120 are disposed adjacent to each other in the axial direction of the central axis AX. That is, for example, the second unit 120 and the first unit 110 are disposed so that the end face of the main body abutting portion 21 on the inner side 330 contacts the surface of the inner peripheral end 71c on the outer side 340. Furthermore, the rotating shaft 200 is inserted into the first unit 110 and the second unit 120. As a result, the first lip portion 23 and the conductive lip 50 are each pressed circumferentially against the outer circumferential surface 210 of the rotating shaft 200. In this way, an arrangement structure of the sealing device is obtained, which is configured by incorporating the sealing device 100 into the housing 300.

[0039] 2, the first lip portion 23 is inclined in a direction toward the outer side 340 of the housing 300 toward the tip side of the first lip portion 23. The conductive lip 50 is inclined in a direction toward the inner side 330 of the housing 300 toward the tip side of the conductive lip 50. In other words, the inclination direction of the first lip portion 23 and the inclination direction of the conductive lip 50 are opposite to each other.

[0040] Here, the process of assembling the conductive lip 50 to the metal ring 70 to produce the second unit 120 can be performed, for example, as follows. Before being assembled to the metal ring 70, the conductive lip 50 has a flat, donut-like shape, as shown in FIG. 4 . This conductive lip 50 is inserted into the first metal ring 71 so as to be positioned along the first inward extending portion 71b. Next, the second metal ring 72 is press-fitted into the first metal ring 71 (the first metal ring 71 is fitted over the second metal ring 72), and the first metal ring 71 and the second metal ring 72 are crimped and fixed to each other, and a portion (the radially outer portion) of the conductive lip 50 is compressed and held by the first inward extending portion 71b and the second inward extending portion 72b. As described above, the inner circumferential end of the second inward extending portion 72b (the inner circumferential end 72c of the second metal ring 72) is located radially outward from the inner circumferential end of the first inward extending portion 71b (the inner circumferential end 71c of the first metal ring 71). Therefore, when a portion (the radially outer portion) of the conductive lip 50 is compressed by the first inward extending portion 71b and the second inward extending portion 72b, causing strain in the conductive lip 50, as shown in FIG. 3B , the portion of the conductive lip 50 that extends radially inward from the inward extending portion 70b bends toward the second inward extending portion 72b (to the right in FIGS. 3B and 2 ). Note that the present invention is not limited to this example, and the conductive lip 50 may already be bent before being sandwiched (compressed) between the first inward extending portion 71b and the second inward extending portion 72b. Here, before the rotating shaft 200 is inserted into the sealing device 100, the portion of the conductive lip 50 that extends radially inward from the inward extension portion 70b may extend in a straight line, as shown in Figure 3 (b), or even before the rotating shaft 200 is inserted into the sealing device 100, the portion of the conductive lip 50 that extends radially inward from the inward extension portion 70b may extend in an arc shape, as shown in Figure 2.

[0041] Here, before the rotating shaft 200 is inserted into the sealing device 100, it is preferable that the inner diameter D2 ( FIG. 3( b) ) of the conductive lip 50 is smaller than the inner diameter D1 ( FIG. 3( a) ) of the first lip portion 23. By doing so, it is possible to realize a structure in which the contact area between the rotating shaft 200 and the conductive lip 50 is larger than the contact area between the rotating shaft 200 and the first lip portion 23 after the rotating shaft 200 is inserted into the sealing device 100. That is, it is possible to realize a structure in which the distance L2 is longer than the distance L1 shown in FIG. 2 . This makes it possible to more reliably ensure electrical continuity by the conductive lip 50. Note that the first lip portion 23 has higher rigidity than the conductive lip 50, and therefore, even if the contact area between the rotating shaft 200 and the first lip portion 23 is smaller than the contact area between the rotating shaft 200 and the conductive lip 50, it is possible to sufficiently ensure the sealing performance of the first lip portion 23.

[0042] Second Embodiment Next, a second embodiment will be described with reference to Fig. 5. The sealing device 100 according to this embodiment differs from the sealing device 100 according to the first embodiment in the points described below, but is otherwise configured similarly to the sealing device 100 according to the first embodiment.

[0043] In the first embodiment described above, the sealing device 100 is configured to include a first unit 110 and a second unit 120 that are separate from each other. In contrast, in the case of the present embodiment, the sealing device 100 is configured as an integrated unit.

[0044] In this embodiment, the dimension of the main body contact portion 21 of the seal main body constituent member 20 in the axial direction of the central axis AX is smaller than that of the first embodiment. Also, the protruding length of the main body contact portion 21 from the main body inward extending portion 22 is smaller than that of the first embodiment.

[0045] In this embodiment, the sealing device 100 includes a metal ring 40 instead of the metal ring 70. The metal ring 40 has a contact portion 41 that contacts the housing 300, and an inward extending portion 42 that extends radially inward from the contact portion 41 and holds the conductive lip 50.

[0046] The metal ring 40 is attached to the seal body 10, and the conductive lip 50 is integrated with the seal body 10 by being sandwiched between the inward extension 42 and the seal body 10. This makes it possible to reduce the number of parts and the installation space compared to the first embodiment, and to achieve good integration between the conductive lip 50 and the seal body 10. More specifically, the metal ring 40 is fixed to the seal body constituent member 20.

[0047] The abutment portion 41 is formed, for example, in a cylindrical shape concentric with the central axis AX. However, the abutment portion 41 has an extremely short axial dimension. The abutment portion 41 is fixed by crimping to the outer peripheral surface of the tip end portion (the tip end portion of the inner side 330) of the main body abutment portion 21. The outer peripheral surface of the abutment portion 41 is pressed circumferentially against the inner peripheral surface 310 of the axial hole 301.

[0048] The inward extending portion 42 of the metal ring 40 includes, for example, an outer flange portion 421, an intermediate cylindrical portion 422, and an inner flange portion 423. The outer flange portion 421 extends radially inward from the end of the inner side 330 of the abutting portion 41 in an inner flange-like manner. The outer flange portion 421 is disposed along the tip surface (end surface of the inner side 330) of the main body abutting portion 21. The outer flange portion 421 is formed in a flat plate shape perpendicular to the central axis AX and in a donut shape. The intermediate cylindrical portion 422 is formed in a cylindrical shape coaxial with the central axis AX. The intermediate cylindrical portion 422 extends from the radially inner end of the outer flange portion 421 toward the outer side 340. The intermediate cylindrical portion 422 is disposed along the inner circumferential surface of the main body abutting portion 21 extending from the main body inward extending portion 22 toward the inner side 330. The inner flange portion 423 extends radially inward from the end of the intermediate cylindrical portion 422 on the outer side 340 side. The inner flange portion 423 is formed in a flat, donut-like shape perpendicular to the central axis AX. The inner flange portion 423 is disposed along the surface of the main body inward extension portion 22 facing the inner side 330. The metal ring 40 is formed in a three-dimensional shape corresponding to the movement trajectory of the cut end surface shape of the metal ring 40 shown in FIG. 5 when the cut end surface shape is rotated once around the central axis AX. The inner flange portion 423, together with the main body inward extension portion 22 of the seal main body constituent member 20, sandwiches a portion (the radially outer portion) of the conductive lip 50.

[0049] The material of the metal ring 40 is the same as the material of the metal ring 70 (the first metal ring 71 and the second metal ring 72). The metal ring 40 can also be formed by press working or forging.

[0050] In this embodiment, the seal body constituent member 20 has a recess 22a in which a portion (a radially outer portion) of the conductive lip 50 is disposed. Therefore, during and after assembling the sealing device 100, the conductive lip 50 can be more stably positioned and fixed to the seal body constituent member 20, and ultimately to the seal body 10. In other words, the sealing device 100 is easy to manufacture and has excellent structural stability.

[0051] The recess 22a is formed on the inner side 330 (right side in FIG. 5 ) of the main body inward extension portion 22. The depth of the recess 22a (the dimension along the central axis AX) is less than the thickness of the conductive lip 50 before assembly to the seal body 10, and the conductive lip 50 is sandwiched in a compressed state between the inner flange portion 423 and the bottom surface of the recess 22a. The outer peripheral edge of the conductive lip 50 is positioned by the outer peripheral edge of the recess 22a. In this way, the conductive lip 50 is fitted to the seal body constituent member 20.

[0052] Here, the distance from the inner peripheral edge to the outer peripheral edge of the conductive lip 50 in the radial direction, i.e., {(outer diameter of the conductive lip 50) - (inner diameter of the conductive lip 50)} / 2, is shorter than the distance from the outer peripheral surface 210 of the rotating shaft 200 to the inner peripheral surface 310 of the housing 300, i.e., {(inner diameter of the shaft hole 301) - (outer diameter of the rotating shaft 200)} / 2. The outer peripheral edge of the conductive lip 50 is located radially inward of the contact surface 21a of the seal body constituent member 20. More specifically, the outer peripheral edge of the conductive lip 50 is located radially inward of the inner peripheral surface of the intermediate cylindrical portion 422. This makes it easy to realize a structure in which the conductive lip 50 is fitted into the recess 22a.

[0053] The assembly of the conductive lip 50 and the metal ring 40 to the seal body 10 can be performed, for example, by aligning the conductive lip 50 with the recess 22a and then fitting the metal ring 40 into the seal body 10.

[0054] Here, the inner circumferential end 40a of the inward extending portion 42 (the inner circumferential end of the inner flange portion 423) is located radially outward from the inner circumferential end of the portion of the seal body 10 that clamps the conductive lip 50 (the inner circumferential end 22d of the portion of the main body inward extending portion 22 that clamps the conductive lip 50). As a result, a portion of the conductive lip 50 (the radially outer portion) is clamped in a compressed state between the main body inward extending portion 22 and the inner flange portion 423, and thereby, by a mechanism similar to that described in the first embodiment using Figures 4 and 3(b), the portion of the conductive lip 50 that extends radially inward beyond the inward extending portion 42 is bent toward the interior side 330 within the housing 300.

[0055] The sealing device 100 is fixed to the housing 300 by being inserted into the shaft hole 301 so that the outer peripheral surface and contact surface 21a of the abutment portion 41 are pressed against and fixed to the inner peripheral surface 310. Furthermore, the rotating shaft 200 is inserted into the sealing device 100. As a result, the first lip portion 23 and the conductive lip 50 are each pressed against the outer peripheral surface 210 of the rotating shaft 200 in a circumferential manner. This results in a sealing device arrangement structure configured by incorporating the sealing device 100 into the housing 300. In this embodiment, when the rotating shaft 200 is inserted into the sealing device 100, the distance L2 is longer than the distance L1 shown in FIG. 5 , and the contact area between the rotating shaft 200 and the conductive lip 50 is larger than the contact area between the rotating shaft 200 and the first lip portion 23. Furthermore, before the rotating shaft 200 is inserted into the sealing device 100 (not shown), the inner diameter of the conductive lip 50 is smaller than the inner diameter of the first lip portion 23.

[0056] While the embodiments and modifications have been described above with reference to the drawings, these are merely examples of the present invention, and various other configurations may be adopted. Furthermore, the above embodiments and modifications may be combined in any manner without departing from the spirit of the present invention.

[0057] This embodiment encompasses the following technical ideas: (1) A sealing device disposed in a gap between an outer peripheral surface of a rotating shaft and an inner peripheral surface of a shaft hole in a housing having the shaft hole into which the rotating shaft is inserted, for sealing the gap, the sealing device comprising: a first lip portion; a second lip portion disposed in the housing more inward than the first lip portion; and a metal ring holding the second lip portion, wherein the second lip portion is a conductive lip made of a conductive material, and the metal ring has an abutment portion that abuts against the housing and an inward extending portion that extends radially inward from the abutment portion and holds the conductive lip. (2) The sealing device described in (1), wherein the first lip portion is inclined in a direction toward the exterior of the housing toward a tip side of the first lip portion, and the conductive lip portion is inclined in a direction toward the interior of the housing toward the tip side of the conductive lip. (3) The sealing device described in (1) or (2), wherein the metal ring is configured with a first metal ring and a second metal ring, the first metal ring has a first cylindrical portion and a first inward extending portion extending radially inward from the first cylindrical portion, the second metal ring has a second cylindrical portion arranged along the inner surface of the first cylindrical portion and a second inward extending portion extending radially inward from the second cylindrical portion and arranged along the first inward extending portion, the first cylindrical portion and the second cylindrical portion form the abutment portion, the first inward extending portion and the second inward extending portion form the inward extending portion, and the conductive lip is held by being clamped between the first inward extending portion and the second inward extending portion. (4) The second inward extension portion is positioned more inward within the housing than the first inward extension portion, the inner circumferential end of the second inward extension portion is positioned radially outward than the inner circumferential end of the first inward extension portion, and the portion of the conductive lip that extends radially inward more than the inward extension portion is bent toward the interior of the housing. (3) A sealing device as described in(5) The sealing device according to any one of (1) to (4), further comprising a seal body, the seal body comprising: a core made of a metal material; and a seal body constituent member made of an elastic body and integrated with the core, the seal body constituent member including the first lip portion. (6) The sealing device according to (5), wherein the metal ring is attached to the seal body, and the conductive lip is integrated with the seal body by being sandwiched between the inward extending portion and the seal body. (7) The sealing device according to (6), wherein an inner circumferential end of the inward extending portion is located radially outward from an inner circumferential end of a portion of the seal body that sandwiches the conductive lip, and a portion of the conductive lip that extends radially inward beyond the inward extending portion is bent toward the interior of the housing. (8) The sealing device according to any one of (1) to (7), wherein an inner diameter of the conductive lip is smaller than an inner diameter of the first lip portion before the rotating shaft is inserted into the sealing device. (9) The sealing device according to any one of (1) to (8), wherein a contact area between the rotating shaft and the conductive lip is larger than a contact area between the rotating shaft and the first lip portion after the rotating shaft is inserted into the sealing device. (10) The sealing device according to any one of (1) to (9), wherein the first lip portion is a dust lip.

[0058] This application claims priority based on Japanese Patent Application No. 2023-37277, filed March 10, 2023, the disclosure of which is incorporated herein in its entirety by reference.

[0059] REFERENCE SIGNS LIST 10 Seal body 20 Seal body constituent member 21 Body contact portion 21a Contact surface 22 Body inward extending portion 22a Recessed portion 22d Inner peripheral end 23 First lip portion 25 Outward extending portion 30 Core metal 31 Cylindrical portion 31a Contact surface 32 Core metal inward extending portion 32a Contact surface 32b Bent portion 40 Metal ring 40a Inner peripheral end 41 Contact portion 42 Inward extending portion 42a Recessed portion 42b Bent portion 50 Conductive lip (second lip portion) 70 Metal ring 70a Contact portion 70b Inward extending portion 71 First metal ring 71a First cylindrical portion 71b First inward extending portion 71c Inner peripheral end 72 Second metal ring 72a Second cylindrical portion 72b Second inward extending portion 72c Inner peripheral end 90 Slinger 100 Sealing device 110 First unit 120 Second unit 200 Rotating shaft 210 Outer peripheral surface 300 Housing 301 Shaft hole 310 Inner peripheral surface 320 Gap 330 Inner side 340 Outer side 421 Outer flange portion 422 Intermediate cylindrical portion 423 Inner flange portion 1000 Sealing device 1201 First rotating shaft 1202 Second rotating shaft 1203 Third rotating shaft 1220 Gear 1300 Housing 1400 Bearing 1500 Battery 1600 Inverter 1700 Electric motor 1800 Wheel 1900 Reducer

Claims

1. 1. A sealing device that is disposed in a gap between an outer peripheral surface of a rotating shaft and an inner peripheral surface of a shaft hole in a housing having the shaft hole into which the rotating shaft is inserted, and seals the gap, A first lip portion; a second lip portion disposed inside the housing and closer to the interior than the first lip portion; a metal ring that holds the second lip portion; Equipped with the second lip portion is a conductive lip made of a conductive material, the metal ring has a contact portion that contacts the housing, and an inward extending portion that extends radially inward from the contact portion and holds the conductive lip, the metal ring is configured to include a first metal ring and a second metal ring, The first metal ring is A first cylindrical portion; a first inward extending portion extending radially inward from the first cylindrical portion; and The second metal ring is a second cylindrical portion disposed along an inner circumferential surface of the first cylindrical portion; a second inward extending portion extending radially inward from the second cylindrical portion and disposed along the first inward extending portion, the first cylindrical portion and the second cylindrical portion constitute the abutment portion, the first inward extending portion and the second inward extending portion constitute the inward extending portion, the conductive lip is held by being sandwiched between the first inward extending portion and the second inward extending portion, the second inward extension portion is disposed more inwardly within the housing than the first inward extension portion, an inner circumferential end of the second inward extending portion is located radially outward of an inner circumferential end of the first inward extending portion, A sealing device in which a portion of the conductive lip that extends radially inward beyond the inward extending portion is bent toward the interior of the housing.

2. A sealing device disposed in a gap between an outer peripheral surface of a rotating shaft and an inner peripheral surface of a shaft hole in a housing having the shaft hole into which the rotating shaft is inserted, to seal the gap, A first lip portion; a second lip portion disposed inside the housing and closer to the interior than the first lip portion; a metal ring that holds the second lip portion; Equipped with the second lip portion is a conductive lip made of a conductive material, the metal ring has a contact portion that contacts the housing, and an inward extending portion that extends radially inward from the contact portion and holds the conductive lip, Further comprising a seal body, The seal body is a core made of a metal material; a seal body component made of an elastic body and integrated with the core metal; It is configured with the seal body component includes the first lip portion, the metal ring is attached to the seal body; the conductive lip is integrated with the seal body by being sandwiched between the inward extension and the seal body, an inner circumferential end of the inward extending portion is located radially outward of an inner circumferential end of a portion of the seal body that sandwiches the conductive lip; A sealing device in which a portion of the conductive lip that extends radially inward beyond the inward extending portion is bent toward the interior of the housing.

3. the first lip portion is inclined toward a tip end side of the first lip portion in a direction toward an outer side of the housing, The sealing device according to claim 1 or 2, wherein the conductive lip is inclined in a direction toward the inside of the housing toward a tip side of the conductive lip.

4. the metal ring is configured to include a first metal ring and a second metal ring, The first metal ring is A first cylindrical portion; a first inward extending portion extending radially inward from the first cylindrical portion; and The second metal ring is a second cylindrical portion disposed along an inner circumferential surface of the first cylindrical portion; a second inward extending portion extending radially inward from the second cylindrical portion and disposed along the first inward extending portion, the first cylindrical portion and the second cylindrical portion constitute the abutment portion, the first inward extending portion and the second inward extending portion constitute the inward extending portion, The sealing device according to claim 2 , wherein the conductive lip is held by being sandwiched between the first inward extending portion and the second inward extending portion.

5. Further comprising a seal body, The seal body is a core made of a metal material; a seal body component made of an elastic body and integrated with the core metal; It is configured with The sealing device according to claim 1 , wherein the seal body component includes the first lip portion.

6. the metal ring is attached to the seal body; The sealing device according to claim 5 , wherein the conductive lip is integrated with the seal body by being sandwiched between the inward extension and the seal body.

7. 3. The sealing device according to claim 1, wherein an inner diameter of the conductive lip is smaller than an inner diameter of the first lip portion before the rotating shaft is inserted into the sealing device.

8. 3. The sealing device according to claim 1, wherein after the rotating shaft is inserted into the sealing device, a contact area between the rotating shaft and the conductive lip is larger than a contact area between the rotating shaft and the first lip portion.

9. The sealing device according to claim 1 or 2, wherein the first lip portion is a dust lip.

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