Sealing device

Abstract

A sealing device (100) is disposed in 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) having the shaft hole (301) into which the rotating shaft (200) is inserted, and seals the gap (320). The sealing device (100) is provided with a core metal (30) composed of a metal material, and a seal body constituent member (20) which is composed of an elastic body and in which the core metal (30) is integrated. The seal body constituent member (20) is provided with: a seal body (10) including a lip part (23); and a conductive lip (50) and a conductive protective ring (40) which are attached to the seal body (10). The protective ring (40) has an abutting part (41) abutting on the housing (300), and an inward extension part (42) extending radially inward from the abutting part (41). The conductive lip (50) is integrated with the seal body (10) by being held between the inward extension part (42) and the seal body (10).

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. 10 , 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. 10 , 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 10, 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, the technology of Patent Document 1 leaves room for improvement in terms of the integrity of the conductive lip and the seal body.

[0008] The present invention has been made in view of the above problems, and provides a sealing device having a structure that can achieve good integration between a conductive lip and a seal body.

[0009] According to the present invention, there is provided a sealing device that is disposed 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 the shaft hole into which the rotating shaft is inserted, and seals the gap, the sealing device comprising: a core wire made of a metal material; and a seal body constituent member made of an elastic body and integrated with the core wire, the seal body constituent member comprising: a seal body including a lip portion; and a conductive lip and a conductive protective ring attached to the seal body, the protective ring having an abutment portion that abuts against the housing and an inward extension portion that extends radially inward from the abutment portion, and the conductive lip is integrated with the seal body by being clamped between the inward extension portion and the seal body.

[0010] According to the present invention, it is possible to achieve good integration between the conductive lip and the seal body.

[0011] FIG. 1 is a view showing a sealing device according to a first embodiment, showing a cross-sectional end surface along the axis of a rotating shaft. FIG. 2 is a partially enlarged view of FIG. 1. FIG. 3 is a view showing a sealing device according to a first modified example of the first embodiment, showing a cross-sectional end surface along the axis of the rotating shaft. FIG. 4 is a view showing a sealing device according to a second modified example of the first embodiment, showing a cross-sectional end surface along the axis of the rotating shaft. FIG. 5 is a view showing a sealing device according to a fifth modified example of the first embodiment, showing a cross-sectional end surface along the axis of the rotating shaft. FIG. 6 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 using Figures 1 and 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, into which the rotating shaft 200 is inserted, to seal the gap 320. The sealing device 100 includes a seal body 10, a conductive lip 50 attached to the seal body 10, and a conductive protective ring 40. The seal body 10 includes a core 30 made of a metal material and a seal body component 20 made of an elastic material and integrated with the core 30. The seal body component 20 includes a lip portion 23. The protective ring 40 has an abutment portion 41 that abuts against the housing 300 and an inward extension portion 42 that extends radially inward from the abutment portion 41. The conductive lip 50 is integrated with the seal body 10 by being sandwiched between the inward extension 42 and the seal body 10 .

[0014] Here, 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 is referred to as the radial direction. Furthermore, within the radial direction, a direction away from the central axis AX is referred to as the radially outer direction, and a direction approaching the central axis AX is referred to as the radially inner direction. Furthermore, a direction circumferentially around the central axis AX is 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 is referred to as the inner side 330. The other side (the 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.

[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 protective ring 40 and the conductive lip 50 each form a portion of a 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 protective ring 40 and the conductive lip 50, i.e., the rotating shaft can be grounded to the housing 300. This makes it possible to suppress the generation of AM radio electromagnetic noise from the rotating shaft and electrolytic corrosion of the bearing. Furthermore, according to the sealing device 100 of this embodiment, the conductive lip 50 is integrated with the seal body 10 by being sandwiched between the inward extension 42 and the seal body 10, thereby achieving good integration between the conductive lip 50 and the seal body 10. Because the sealing device 100 can be used to replace an existing sealing device, a dedicated space for an earth brush is not required, and the generation of brush wear powder can be prevented. Furthermore, unlike the technology that ensures electrical continuity between the rotating shaft 200 and the housing 300 using the conductive lip alone, this technology ensures electrical continuity using the conductive lip 50 and the protective ring 40, which is a metal member, and therefore it is also possible to reduce the electrical resistance of the conductive path from the rotating shaft 200 to the housing 300.

[0016] In the present invention, the lip portion 23 may be an oil lip or a dust lip. In this embodiment, the lip portion 23 is an oil lip. That is, the seal body 10 constitutes an oil seal body. The sealing device 100 combines the seal body 10 having the lip portion 23, which is an oil lip, with the conductive lip 50, thereby achieving both oil sealing performance and conductivity while reducing the number of parts and installation space. By locating the conductive lip 50 on the outer side 340 (atmosphere side) of the contact point between the lip portion 23, which is an oil lip, and the rotating shaft 200, conductivity can be imparted without impairing oil sealing performance. The sealing device 100 uses the lip portion 23 and the conductive lip 50 to prevent foreign matter from entering from the outer side 340 to the inner side 330, and the lip portion 23 to prevent lubricant leakage from the inner side 330 to the outer side 340.

[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] The seal body constituent member 20 is formed in an annular shape centered on the central axis AX. The seal body constituent member 20 includes, for example, a body contact portion 21 formed in a cylindrical shape concentric with the central axis AX, a body inward extension portion 22 extending radially inward from one end (the end on the outer side 340) of the body contact portion 21 in the axial direction like an inner flange, and a lip portion 23 extending axially (toward the inner side 330) from the radially inner end of the body inward extension portion 22. The lip portion 23 also has a cylindrical shape concentric with the central axis AX. The lip portion 23 is spaced apart from and positioned inside the body contact portion 21, and the body contact portion 21 and the lip portion 23 face each other radially. The seal body constituent member 20 is formed in a three-dimensional shape corresponding to the movement trajectory of the cut end surface shape of the seal body constituent member 20 shown in FIG. 2 when the cut end surface shape is rotated once around the central axis AX. A portion of the outer peripheral surface of the main 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 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 lip portion 23 and the outer peripheral surface 210. Hereinafter, the pressed contact points between the contact surface 21a and the inner peripheral surface 310 and the pressed contact points between the lip portion 23 and the outer peripheral surface 210 will be collectively referred to as the sealed areas. In this embodiment, the lip portion 23 is an oil lip, and a lubricant such as lubricating oil is filled in a region 330 on the inner side of the sealed area.

[0020] Because the 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).

[0021] 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 (and the garter spring 60, which will be described later, if necessary) is placed in a molding die (not shown), an uncrosslinked rubber material is injected, and then the cavity of the molding die 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.

[0022] 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.

[0023] The core metal 30 includes, for example, a cylindrical portion 31 formed concentrically with the central axis AX, and a core metal inward extension portion 32 extending radially inward in the form of an inner flange from one end (the end of the outer side 340) of the cylindrical portion 31 in the axial direction. In this embodiment, the core metal inward extension portion 32 is formed in a flat, donut-like shape perpendicular to the central axis AX. The core metal 30 is formed in a three-dimensional shape corresponding to the movement trajectory of the cut end surface shape of the core metal 30 shown in FIG. 2 when the cut end surface shape is rotated once around the central axis AX. In this embodiment, the core metal 30 is entirely embedded in the seal body component 20 and is not exposed from the seal body component 20. The cylindrical portion 31 is disposed, for example, from the interior of the main body contact portion 21 to the interior of the boundary between the main body contact portion 21 and the main body inward extension portion 22. The core inward extending portion 32 is disposed from the interior of the boundary between the main body abutting portion 21 and the main body inward extending portion 22 to the interior of the main body inward extending portion 22. For example, the inner peripheral edge of the core inward extending portion 32 is located near the boundary between the main body inward extending portion 22 and the lip portion 23.

[0024] As described above, the protective ring 40 has an abutment portion 41 and an inward extending portion 42. The abutment portion 41 is formed, for example, in a cylindrical shape concentric with the central axis AX. The inward extending portion 42 extends radially inward from one end (the end on the outer side 340) of the abutment portion 41 in the axial direction, forming an inner flange shape. In this embodiment, the inward extending portion 42 is formed in a flat plate shape perpendicular to the central axis AX and in a donut shape. The protective ring 40 is formed in a three-dimensional shape corresponding to the movement trajectory of the cut end surface shape of the protective ring 40 shown in FIG. 2 when the cut end surface shape is rotated once around the central axis AX. The outer peripheral surface of the abutment portion 41 is pressed against the inner peripheral surface 310 of the shaft hole 301 in a circumferential manner. The protective ring 40 is preferably made of a metal material, such as stainless steel (SUS) or cold-rolled steel (SPCC). The protection ring 40 can be formed by press working or forging.

[0025] The conductive lip 50 is formed in a doughnut shape centered on the central axis AX. A portion (a radially outer portion) of the conductive lip 50 is disposed along a surface of the main body inward extension portion 22 of the seal body constituent member 20 facing the outer side 340. In this embodiment, the radially inner portion of the conductive lip 50 extends radially inward beyond the inward extension portion 42. The radially inner portion of the conductive lip 50 protrudes radially inward from the radially inner end of the main body inward extension portion 22. The portion of the conductive lip 50 extending radially inward beyond the inward extension portion 42 is bent toward the outer side 340 (the left side in FIG. 2 ). 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 is in circumferential contact with the outer circumferential surface 210 of the rotating shaft 200, thereby ensuring electrical continuity between the rotating shaft 200 and the conductive lip 50. Note that the tip end of the conductive lip 50 slides against the outer circumferential surface 210 when the rotating shaft 200 rotates.

[0026] 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).

[0027] The garter spring 60 is composed of a coil spring, both ends of which are connected to each other, and the axial center of the coil spring forms an annular loop. The axial center of the coil spring makes one revolution around the central axis AX. That is, the garter spring 60 is formed in an annular shape along the circumferential direction. The garter spring 60 is a tension-type coil spring and exerts a biasing force in a direction that shortens its axial length. Because the garter spring 60 has an annular loop shape, the garter spring 60 exerts a biasing force in a direction that shortens the radius of the loop. The garter spring 60 is disposed in a groove formed around the outer peripheral surface of the lip portion 23 (the surface facing the cylindrical portion 31) and biases the lip portion 23 radially inward. Therefore, the garter spring 60 functions to restrain the lip portion 23 against the rotating shaft 200. This allows the inner peripheral edge of the lip portion 23 to be pressed firmly against the outer peripheral surface 210 of the rotating shaft 200.

[0028] The portion of lip portion 23 that is pressed against outer peripheral surface 210 is a portion that is separated (separated toward inner side 330) from the boundary between main body inward extending portion 22 and lip portion 23. The portion of lip portion 23 that is closer to main body inward extending portion 22 than the portion that is pressed against outer peripheral surface 210, and the boundary between lip portion 23 and main body inward extending portion 22, are not in contact with outer peripheral surface 210, and gaps are generated between these portions and outer peripheral surface 210.

[0029] In this embodiment, the seal body constituent member 20 sandwiches the conductive lip 50 together with the inward extending portion 42 of the protective ring 40. More specifically, of the core metal 30 and the seal body constituent member 20, only the seal body constituent member 20 sandwiches the conductive lip 50 (the radially outer portion of the conductive lip 50) together with the inward extending portion 42, and the core metal 30 does not sandwich the conductive lip 50. The inward extending portion 42 is disposed along the surface of the outer side 340 (left side in FIG. 2 ) of the main body inward extending portion 22, and the conductive lip 50 is sandwiched between the main body inward extending portion 22 and the inward extending portion 42.

[0030] In this embodiment, the seal body constituent member 20 has a recess 22a in which a portion of the conductive lip 50 (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.

[0031] The recess 22a is formed on the outer side 340 (left side in FIG. 2 ) of the main body inward extension 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 inward extension 42 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.

[0032] Here, the radial distance from the inner peripheral edge to the outer peripheral edge of the conductive lip 50, 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 component 20. More specifically, the outer peripheral edge of the conductive lip 50 is located radially inward of the inner peripheral surface (abutment portion 41) of the protective ring 40. This facilitates the realization of a structure in which the conductive lip 50 is fitted into the recess 22a. Because the conductive lip 50 is formed to these dimensions, 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) (unlike the conductive lip in Patent Document 1 (the front-mounted seal in the same document)).

[0033] In this embodiment, the protective ring 40 is fixed to the seal body constituent member 20. More specifically, the abutting portion 41 of the protective ring 40 is crimped and fixed to the outer peripheral surface of the end portion of the outer side 340 of the seal body constituent member 20. In the axial direction, the range in which the abutting portion 41 is arranged generally overlaps the range in which the main body inward extending portion 22 of the seal body constituent member 20 is arranged, and the abutting portion 41 is crimped and fixed to the outer peripheral surface of the boundary between the main body abutting portion 21 and the main body inward extending portion 22.

[0034] The sealing device 100 is configured as described above.

[0035] The assembly work of the conductive lip 50 and the protective ring 40 to the seal body 10 can be performed, for example, by first aligning the conductive lip 50 with the seal body 10 and then fitting the protective ring 40 to the seal body 10. That is, after a portion (the radially outer portion) of the conductive lip 50 is placed in the recess 22a of the body inward extension portion 22, the abutment portion 41 of the protective ring 40 is fitted externally onto the seal body constituent member 20, thereby assembling the conductive lip 50 and the protective ring 40 to the seal body 10.

[0036] Here, before the conductive lip 50 is assembled to the seal body 10, the conductive lip 50 may be entirely flat, or may be bent as shown in FIG. 2 from the state before the conductive lip 50 is assembled to the seal body 10. If the conductive lip 50 is flat (donut-shaped) before assembly to the seal body 10, when the conductive lip 50 is assembled to the seal body 10, the radially outer portion of the conductive lip 50 is sandwiched and compressed between the inward extension portion 42 and the main body inward extension portion 22, causing strain in the conductive lip 50. As a result, the portion of the conductive lip 50 that extends radially inward beyond the inward extension portion 42 bends toward the inward extension portion 42 (to the left in FIG. 2 ). This is because the inner circumferential end of the inward extension portion 42 is located radially outward from the inner circumferential end of the portion of the main body inward extension portion 22 that is arranged along the conductive lip 50.

[0037] The sealing device 100 is fixed to the housing 300. That is, the sealing device 100 is inserted into the axial hole 301 so that the contact surface 21 a and the abutment portion 41 are pressed against and fixed to the inner circumferential surface 310, thereby fixing the sealing device 100 to the housing 300.

[0038] Here, it is preferable that the inner diameter of the conductive lip 50 is smaller than the inner diameter of the lip portion 23 before the rotating shaft 200 is inserted into the sealing device 100. By doing so, a structure can be realized 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 lip portion 23 after the rotating shaft 200 is inserted into the sealing device 100. That is, a structure can be realized 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 through the conductive lip 50. Note that the 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 lip portion 23 is smaller than the contact area between the rotating shaft 200 and the conductive lip 50, sufficient sealing performance by the lip portion 23 can be ensured.

[0039] <Modification 1 of First Embodiment> Next, Modification 1 of the first embodiment will be described with reference to Fig. 3. The sealing device 100 according to this modification 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.

[0040] In this modified example, the radially inner end (edge) of the inward extending portion 42 of the protective ring 40 forms a bent portion 42b that is bent toward the conductive lip 50. As a result, the bent portion 42b presses against the conductive lip 50, so that the tip of the conductive lip 50 can always maintain contact with the outer peripheral surface 210 of the rotating shaft 200. This makes it possible to prevent a decrease in the adhesion of the conductive lip 50 to the rotating shaft 200 due to deterioration of the conductive lip 50 over time, and maintain electrical continuity between the rotating shaft 200 and the housing 300.

[0041] More specifically, the bent portion 42b is bent toward one side (the inner side 330: the right side in FIG. 3 ) based on the portion of the inward extending portion 42 other than the bent portion 42b. In other words, the bent portion 42b is bent in the direction opposite to the bending direction of the conductive lip 50 (the left side in FIG. 3 ), and presses the conductive lip 50 in that direction. This allows the bent portion 42b to press the conductive lip 50 against the rotating shaft 200, and prevents the conductive lip 50 from deforming in a direction away from the rotating shaft 200 (radially outward) even if the conductive lip 50 deteriorates over time.

[0042] <Modification 2 of First Embodiment> Next, Modification 2 of the first embodiment will be described with reference to Fig. 4. The sealing device 100 according to this modification 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 this modified example, the core metal 30 sandwiches the conductive lip 50 together with the inward extending portion 42 of the protective ring 40. Because the core metal 30 is a metal member with higher rigidity than the seal body constituent member 20, the conductive lip 50 can be more stably sandwiched between the inward extending portion 42 and the seal body 10.

[0044] More specifically, the radially outer portion of the conductive lip 50, particularly the radially outer portion, is sandwiched between the inward extending portion 42 and the metal core 30, and the radially outer portion of the conductive lip 50, particularly the radially inner portion, is sandwiched between the inward extending portion 42 and the seal body constituent member 20. However, the present invention is not limited to this example, and in the seal body 10, the portion that sandwiches the radially outer portion of the conductive lip 50 together with the inward extending portion 42 may be only the metal core 30.

[0045] The mandrel inward extending portion 32 is formed, for example, in a flat plate shape perpendicular to the central axis AX, except for a radially inner end (edge) (bent portion 32b described below), and the radially inner end forms a bent portion 32b bent in a crank shape toward the inner side 330 (the right side in FIG. 4 ). In the mandrel inward extending portion 32, a portion formed in a flat plate shape perpendicular to the central axis AX and a boundary portion between the mandrel inward extending portion 32 and the tubular portion 31 are exposed on the outer surface (surface of the outer side 340) of the seal body 10. In addition, in the mandrel inward extending portion 32 of the mandrel 30, a portion of the surface facing the outer side 340 (the left side in FIG. 4 ) forms a contact surface 32a that comes into surface contact with the conductive lip 50.

[0046] In this modified example, the protective ring 40 is fixed to the core metal 30. In other words, since the protective ring 40 is fixed to the core metal 30, which is a metal member, the retention of the protective ring 40 relative to the seal body 10 can be improved.

[0047] More specifically, a portion of the outer peripheral surface of the core 30 from the tubular portion 31 to the boundary between the tubular portion 31 and the core inward extending portion 32 is exposed on the outer peripheral surface of the seal body 10, and this exposed portion has a contact surface 31a that comes into surface contact with the inner peripheral surface of the abutting portion 41 of the protective ring 40. The abutting portion 41 is directly crimped and fixed to the contact surface 31a. More specifically, the contact surface 31a is exposed in a portion of the outer peripheral surface of the seal body 10 that includes the end of the outer side 340. The portion of the tubular portion 31 on the side of the core inward extending portion 32 (i.e., the outer side 340) and the boundary between the tubular portion 31 and the core inward extending portion 32 bulge radially outward (are thicker) than the inner side 330 of the tubular portion 31, and this bulged portion forms the contact surface 31a.

[0048] In this modification, the conductive path from the rotating shaft 200 to the housing 300 includes a path that passes through the conductive lip 50, the core metal 30, and the protective ring 40, in addition to the path that passes through the conductive lip 50 and the protective ring 40. This also makes it possible to reduce the electrical resistance of the conductive path from the rotating shaft 200 to the housing 300.

[0049] In this modification, the seal body component 20 does not have the recess 22a.

[0050] <Modification 3 of First Embodiment> Next, Modification 3 of the first embodiment will be described with reference to Figures 5 and 6. The sealing device 100 according to this modification 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.

[0051] In this modified example, the sealing device 100 further includes a disc spring 70 interposed between the inward extending portion 42 of the protective ring 40 and the conductive lip 50. The disc spring 70 presses the portion of the conductive lip 50 that extends radially inward beyond the inward extending portion 42 toward the opposite side from the inward extending portion 42 (i.e., the inner side 330). This allows the tip of the conductive lip 50 to remain in contact with the outer peripheral surface 210 of the rotating shaft 200. This prevents the conductive lip 50 from losing adhesion to the rotating shaft 200 due to deterioration over time, and maintains electrical continuity between the rotating shaft 200 and the housing 300.

[0052] The shape of the disc spring 70 is not particularly limited. As an example, the disc spring 70 has a flat, doughnut-shaped main body 71 perpendicular to the central axis AX and a plurality of blades 72 protruding radially inward from the inner peripheral edge of the main body 71. The blades 72 are arranged side by side (e.g., at equal intervals) along the circumferential direction of the main body 71. A plurality of slits 73 extending radially are formed in the blades 72. The blades 72 are bent toward the outer side 340 with respect to the main body 71. However, instead of the plurality of blades 72, the disc spring 70 may have an inner peripheral portion (not shown) formed in a shape corresponding to the outer peripheral surface of a truncated cone (frustum cone) centered on the central axis AX. The disc spring 70 is preferably made of a metal material.

[0053] In this modified example, before the conductive lip 50 is sandwiched and compressed between the inward extending portion 42, the disc spring 70, and the main body inward extending portion 22, the entire conductive lip 50 is flat as shown in Fig. 6, and when the conductive lip 50 is sandwiched and compressed between the inward extending portion 42, the disc spring 70, and the main body inward extending portion 22, the conductive lip 50 is bent as shown in Fig. 5. However, the present invention is not limited to this example, and the conductive lip 50 may be bent as shown in Fig. 5 before the conductive lip 50 is sandwiched and compressed between the inward extending portion 42, the disc spring 70, and the main body inward extending portion 22.

[0054] <Fourth Modification of First Embodiment> Next, a fourth modification of the first embodiment will be described with reference to Fig. 7. The sealing device 100 according to this modification 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.

[0055] In this modified example, the portion of the conductive lip 50 extending radially inward beyond the inward extending portion 42 includes a base portion 50a extending radially inward from the inward extending portion 42 and a tip portion 50b folded back radially outward from the radially inner end of the base portion 50a. The sealing device 100 further includes a garter spring 80 disposed at the boundary between the base portion 50a and the tip portion 50b and restraining the portion of the conductive lip 50 extending radially inward beyond the inward extending portion 42 against the rotating shaft 200. The garter spring 80 is similar to the garter spring 60 and is formed in an annular loop shape along the circumferential direction. The garter spring 80 is disposed around the boundary between the base portion 50a and the tip portion 50b of the conductive lip 50, on the surface facing radially outward. As a result, the garter spring 80 presses the conductive lip 50 radially inward. Therefore, according to this modification, it is possible to improve the adhesion of the conductive lip 50 to the rotating shaft 200. In this modification, the portion of the conductive lip 50 that makes circumferential contact and slides against the outer circumferential surface 210 of the rotating shaft 200 is the portion that faces radially inward at the boundary between the base portion 50 a and the tip portion 50 b.

[0056] It is preferable that the portion of the conductive lip 50 that extends radially inward from the inward extension portion 42 be formed thicker than the radially outer portion of the conductive lip 50, and by doing so, excessive deformation of the conductive lip 50 due to the biasing force of the garter spring 80 can be prevented.

[0057] <Fifth Modification of First Embodiment> Next, a fifth modification of the first embodiment will be described with reference to Fig. 8. The sealing device 100 according to this modification 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.

[0058] In this modified example, the portion of the seal body 10 that is disposed along the conductive lip 50 has a backup portion 22b that locally protrudes radially inward. As a result, when assembling a mechanism including the sealing device 100, when the rotating shaft 200 is inserted in the direction of arrow A in FIG. 8 (toward the inner side 330), even if the portion of the conductive lip 50 that extends radially inward beyond the inward extending portion 42 is pressed toward the inner side 330 due to friction with the rotating shaft 200, the conductive lip 50 is supported by the backup portion 22b, thereby preventing the conductive lip 50 from bending and curling toward the inner side 330. More specifically, the portion of the seal body 10 that is disposed along the conductive lip 50 (and the backup portion 22b) is a part of the seal body constituent member 20.

[0059] Second Embodiment Next, a second embodiment will be described with reference to Fig. 9. 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.

[0060] In this embodiment, the lip portion 23 of the seal body 10 is a dust lip. The sealing device 100 combines the seal body 10 having the 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. By locating the conductive lip 50 on the inner side 330 of the contact point between the lip portion 23, which is a dust lip, and the rotating shaft 200, electrical conductivity can be imparted without compromising dust sealing performance. In particular, electrical conductivity can be ensured with a small number of parts, even in water-soaked environments where an earth brush would be difficult to use. The sealing device 100 uses the lip portion 23 and the conductive lip 50 to prevent foreign matter from entering the inner side 330 from the outer side 340. In this embodiment, a separate oil seal (with an oil lip) may be located on the inner side 330 of the conductive lip 50.

[0061] In the first embodiment, the portion of the seal body component 20 disposed along the inner circumferential surface 310 was described as including the main body contact portion 21 and the boundary between the main body contact portion 21 and the main body inward extension portion 22. In contrast, in the present embodiment, the entire portion of the seal body component 20 disposed along the inner circumferential surface 310 is the main body contact portion 21. Therefore, in this embodiment, the main body contact portion 21 of the seal body component 20 is similar to the first embodiment in that it has a cylindrical shape. A portion of the main body contact portion 21 (a portion of the inner side 330) extends in an eave-like manner from the radially outer end of the main body inward extension portion 22 toward the inner side 330 (the right side in FIG. 9 ). In this embodiment, the lip portion 23 extends obliquely from the radially inner end of the main body inward extension portion 22 toward the radially inner side and toward the outer side 340 (the left side in FIG. 9 ).

[0062] The seal body component 20 further includes an outward extension portion 25 extending 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 lip portion 23. In this embodiment, a slinger 90 is fixed to the rotating shaft 200. The slinger 90 rotates in conjunction with the rotation of the rotating shaft 200. 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.

[0063] The recess 22a is formed on the surface of the main body inward extending portion 22 facing the inner side 330. The conductive lip 50 is disposed in the recess 22a and assembled to the seal main body constituent member 20, as in the first embodiment. However, the conductive lip 50 is bent toward the inner side 330 (the right side in FIG. 9 ).

[0064] The cylindrical portion 31 of the core metal 30 is embedded in the main body abutment portion 21. However, a portion of the cylindrical portion 31 may be exposed from the main body abutment portion 21 (from the seal main body constituent member 20). The core metal inward extension portion 32 is embedded from the inside of the boundary between the main body abutment portion 21 and the main body inward extension portion 22 to the inside of the main body inward extension portion 22. The core metal inward extension portion 32 may be formed in the shape of a flat flange, or may be partially bent to fit the shape of the seal main body constituent member 20.

[0065] The abutment portion 41 of the protective ring 40 is formed in a cylindrical shape with an extremely short axial dimension, and is crimped and fixed to the tip end (tip end of the inner side 330) of the part of the main body abutment portion 21 that extends like an eave as described above.

[0066] The inward extending portion 42 of the protective ring 40 includes 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 abutting portion 41 on the inner side 330 in an inner flange-like manner. The outer flange portion 421 is disposed along the tip surface (the end surface of the inner side 330) of the portion of the main body abutting portion 21 that extends in an eave-like manner as described above. 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 portion of the main body abutting portion 21 that extends in an eave-like manner as described above. The inner flange portion 423 extends radially inward from the end of the intermediate cylindrical portion 422 on the outer side 340 in an inner flange-like manner. The inner flange portion 423 is disposed along the surface of the main body inward extending portion 22 that faces the inner side 330. In the present embodiment, the portion of the protective ring 40 that sandwiches the conductive lip 50 together with the main body inward extending portion 22 is the inner flange portion 423.

[0067] While the above embodiments and modifications have been described with reference to the drawings, these are merely illustrative of the present invention, and various other configurations may be employed. For example, while the above describes an example in which the conductive lip 50 is bent, the conductive lip 50 may not be bent and may be entirely disposed on the same plane. Furthermore, while the above describes an example in which the abutting portion 41 of the protective ring 40 is selectively crimped and fixed to either the seal body component 20 or the core metal 30, the abutting portion 41 may be crimped and fixed across both the seal body component 20 and the core metal 30. Furthermore, the above embodiments and modifications may be combined in any manner without departing from the spirit and scope of the present invention.

[0068] This embodiment encompasses the following technical concepts: (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, into which the rotating shaft is inserted, for sealing the gap, the sealing device comprising a core made of a metallic material and a seal body constituent member made of an elastic body and integral with the core, the seal body constituent member comprising a seal body including a lip portion, and a conductive lip and a conductive protective ring attached to the seal body, the protective ring having an abutting portion that abuts against the housing and an inward extending portion that extends radially inward from the abutting portion, the conductive lip being integrated with the seal body by being sandwiched between the inward extending portion and the seal body. (2) The sealing device described in (1), in which the seal body constituent member sandwiches the conductive lip together with the inward extending portion. (3) The sealing device described in (2), in which the seal body constituent member has a recess in which a portion of the conductive lip is disposed. (4) The sealing device according to any one of (1) to (3), wherein the core metal sandwiches the conductive lip together with the inward extending portion. (5) The sealing device according to any one of (1) to (4), wherein the protective ring is fixed to the seal body constituent member. (6) The sealing device according to any one of (1) to (5), wherein the protective ring is fixed to the core metal. (7) The sealing device according to any one of (1) to (6), wherein a radially inner end of the inward extending portion forms a bent portion bent toward the conductive lip. (8) The sealing device according to any one of (1) to (6), further comprising a disc spring interposed between the inward extending portion and the conductive lip, wherein the disc spring presses a portion of the conductive lip that extends radially inward beyond the inward extending portion toward the opposite side to the inward extending portion. (9) The sealing device according to any one of (1) to (8), wherein a portion of the seal body arranged along the conductive lip has a backup portion that locally protrudes radially inward. (10) The sealing device according to any one of (1) to (9), wherein the lip portion is an oil lip.(11) A sealing device according to any one of (1) to (9), wherein the lip portion is a dust lip.

[0069] This application claims priority based on Japanese Patent Application No. 2023-37276, filed March 10, 2023, the disclosure of which is incorporated herein in its entirety by reference.

[0070] REFERENCE SIGNS LIST 10 Seal body 20 Seal body constituent member 21 Body abutment portion 21a Contact surface 22 Body inward extending portion 22a Recessed portion 22b Backup portion 23 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 Protective ring 41 Abutment portion 42 Inward extending portion 42b Bent portion 50 Conductive lip 50a Base portion 50b Tip portion 60 Garter spring 70 Disc spring 71 Body portion 72 Blade portion 73 Slit 80 Garter spring 90 Slinger 100 Sealing device 200 Rotating shaft 210 Outer circumferential 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, The seal body comprises a core made of a metal material and a seal body component made of an elastic body and integrated with the core, the seal body component comprising a seal body including a lip portion, a conductive lip and a conductive protective ring attached to the seal body; Equipped with the protective ring has a contact portion that contacts the housing and an inward extending portion that extends radially inward from the contact portion, The conductive lip is integrated with the seal body by being sandwiched between the inward extension and the seal body.

2. 2. The sealing device according to claim 1, wherein the seal body component sandwiches the conductive lip together with the inwardly extending portion.

3. The sealing device according to claim 2 , wherein the seal body component has a recess in which a portion of the conductive lip is disposed.

4. 2. The sealing device according to claim 1, wherein the core metal sandwiches the conductive lip together with the inwardly extending portion.

5. The sealing device according to claim 1 , wherein the protection ring is fixed to the seal body component.

6. The sealing device according to claim 1 , wherein the protection ring is fixed to the core metal.

7. The sealing device according to claim 1 , wherein a radially inner end of the inward extending portion forms a bent portion that is bent toward the conductive lip.

8. a disc spring interposed between the inward extension and the conductive lip; A sealing device as described in any one of claims 1 to 4, wherein the disc spring presses a portion of the conductive lip that extends radially inward from the inward extension portion toward the opposite side to the inward extension portion.

9. The sealing device according to claim 1 , wherein a portion of the seal body that is disposed along the conductive lip has a backup portion that locally protrudes radially inward.

10. The sealing device according to any one of claims 1 to 4, wherein the lip portion is an oil lip.

11. The sealing device according to any one of claims 1 to 4, wherein the lip portion is a dust lip.