Sealing device

Abstract

A sealing device 10 is provided between a metal shaft 7 and a metal housing 8 that surrounds the shaft 7. The sealing device 10 comprises: a seal part 11 that is elastic and that has a lip 12 which contacts the shaft 7; a metal first support part 21 that is attached to the housing 8 in a state of metal contact therewith and that supports the seal part 11; an electroconductive part 30 that is electrically conductive and that has a contact part 31 which contacts the shaft 7; and a metal second support part 40 that supports the electroconductive part 30 and that positions the contact part 31 to one side of the lip 12 in the axial direction. The second support part 40 is attached to the first support part 21 in a state of metal contact therewith.

Description

sealing device

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

[0002] In equipment equipped with an electric motor, the induced current generated by the motor can cause electromagnetic noise that can adversely affect other equipment. For example, this type of effect can be reduced by discharging the motor current through the grounded housing (motor housing).

[0003] A sealing device (oil seal) is used between the rotating shaft and the housing of a motor to prevent leakage of lubricating oil within the device. Efforts have been made to provide such a sealing device with a conductive path between the rotating shaft and the housing (see, for example, Patent Document 1).

[0004] JP 2023-28280 A

[0005] The sealing device disclosed in Patent Document 1 has a seal portion, a sleeve tube portion, and a conductive portion. A conductive path between the rotating shaft and the housing is obtained by the conductive portion. However, the seal portion, sleeve tube portion, and conductive portion are each separate, and when a sealing device having these components is attached to equipment, handling of the components becomes cumbersome.

[0006] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a sealing device that provides a conductive path between the housing and the shaft and in which the seal portion and the conductive portion are integrated.

[0007] The sealing device of the present invention is a sealing device provided between a metal shaft and a metal housing surrounding the shaft, and comprises: a seal portion that is elastic and has a lip that contacts the shaft; a metal first support portion that is attached to the housing in metal contact and supports the seal portion; a conductive portion that is conductive and has a contact portion that contacts the shaft; and a metal second support portion that supports the conductive portion and positions the contact portion on one axial side of the lip, and the second support portion is attached to the first support portion in metal contact.

[0008] Fig. 1 is a cross-sectional view showing one embodiment of a sealing device of the present invention. Fig. 2 is a cross-sectional view showing an enlarged portion of the sealing device shown in Fig. 1. Fig. 3 is a cross-sectional view showing another embodiment (second embodiment) of the sealing device of the present invention. Fig. 4 is a cross-sectional view showing an enlarged portion of the sealing device shown in Fig. 3. Fig. 5 is an explanatory view showing a modified example of the conductive portion (second embodiment).

[0009] <Outline of Embodiments of the Present Invention> The following is a description of outlines of embodiments of the present invention. (1) A sealing device according to an embodiment of the present invention is a sealing device provided between a metal shaft and a metal housing surrounding the shaft, and includes: a seal portion that is elastic and has a lip that contacts the shaft; a metal first support portion that is attached to the housing in metal contact and supports the seal portion; a conductive portion that is conductive and has a contact portion that contacts the shaft; and a metal second support portion that supports the conductive portion and has the contact portion located on one axial side of the lip, and the second support portion is attached to the first support portion in metal contact.

[0010] In the sealing device according to the embodiment of the present invention, the first support portion is attached to the housing in metal contact with the housing, the second support portion is attached to the first support portion in metal contact with the housing, and the conductive portion is supported by the second support portion. The conductive portion has a contact portion that contacts the shaft. With this configuration, a conductive path is obtained between the housing and the shaft through the conductive portion. The second support portion is attached to the first support portion, thereby obtaining a sealing device in which a seal block comprising the first support portion and the seal portion and a conductive block comprising the second support portion and the conductive portion are integrated.

[0011] (2) The first support portion has a first cylindrical portion attached to the inner periphery of the housing in metallic contact therewith and a first annular portion extending from a portion of the first cylindrical portion in a direction toward the axis, the second support portion has a cylindrical portion attached to the inner periphery of the first cylindrical portion in metallic contact therewith and an annular portion extending from a portion of the cylindrical portion in a direction toward the axis, the lip is provided extending from a portion of the first annular portion toward the axis, and the contact portion is included in a portion of the conductive portion extending from a portion of the annular portion toward the axis. The cylindrical portion of the second support portion is attached to the first cylindrical portion of the first support portion, thereby obtaining a sealing device in which the seal block and the conductive block are integrated.

[0012] (3) In the sealing device of (2), the second support portion and the conductive portion are an inseparable integral part. With this configuration, the conductive block including the second support portion and the conductive portion can be easily attached to the first support portion.

[0013] (4) In the sealing device described in any one of (1) to (3), the conductive portion includes an elastic sheet that is integral with the second support portion and an electrically conductive sheet that is laminated with the elastic sheet, with a portion of the electrically conductive sheet contacting the first support portion and another portion of the electrically conductive sheet being the contact portion that contacts the shaft. According to this configuration, the electrically conductive portion has high conductivity due to the electrically conductive sheet and elasticity due to the elastic sheet. The contact portion of the electrically conductive portion has followability to the shaft. A conductive path is obtained between the housing and the shaft, passing through the metallic first support portion and the electrically conductive sheet of the electrically conductive portion.

[0014] (5) In the sealing device of (1) or (2), the second support portion includes an outer support plate and an inner support plate that is separate from the outer support plate and attached to the outer support plate, the outer support plate having an outer annular portion located on one axial side of a portion of the conductive portion, which is an annular sheet, and the inner support plate having an inner annular portion that sandwiches a portion of the conductive portion between the outer annular portion and the inner support plate. According to this configuration, when the inner support plate is attached to the outer support plate, a portion of the conductive portion, which is an annular sheet, is sandwiched between them. There is no need to integrally mold the second support portion and the conductive portion. This facilitates the manufacture of each component.

[0015] (6) In the sealing device of (5), the outer support plate has a cylindrical outer tube portion attached in metal contact with the inner surface of the cylindrical portion of the first support portion, and the outer annular portion extending from a part of the outer tube portion in a direction toward the axis, the inner support plate has a cylindrical inner tube portion attached in metal contact with the inner surface of the outer tube portion, and the inner annular portion extending from a part of the inner tube portion in a direction toward the axis, and the conductive portion has a conductive sheet and an elastic sheet laminated with the conductive sheet, and the conductive sheet has the contact portion in contact with the inner annular portion and in contact with the axis.

[0016] <Details of the embodiment of the present invention> [Overall configuration of sealing device 10] Fig. 1 is a cross-sectional view showing one embodiment of a sealing device of the present invention. The sealing device 10 shown in Fig. 1 is provided between a metal shaft 7 and a metal housing 8 surrounding the shaft 7. The sealing device 10 prevents leakage of lubricating oil inside the equipment between the shaft 7 and the housing 8. In each drawing, the shaft 7 and the housing 8 are indicated by imaginary lines using two-dot chain lines.

[0017] The directions of the sealing device 10 are defined below. A direction parallel to the central axis C of the shaft 7 is defined as the "axial direction" of the sealing device 10. A direction perpendicular to the central axis C is defined as the "radial direction" of the sealing device 10. A direction along a circle centered on the central axis C is defined as the "circumferential direction" of the sealing device 10. The right side of FIG. 1 is the "one axial side," where a sealing fluid (e.g., lubricant) whose leakage is to be prevented exists. The left side of FIG. 1 is the "other axial side," which is, for example, the atmosphere. The region where the sealing fluid exists is at a higher pressure than the region on the atmosphere side.

[0018] The sealing device 10 has a seal portion 11, a metal first support portion 21, a conductive portion 30, and a metal second support portion 40. The sealing device 10 shown in Fig. 1 is an oil seal having a garter spring 15. Fig. 2 is an enlarged cross-sectional view showing a portion of the sealing device 10 shown in Fig. 1.

[0019] The seal portion 11 is made of rubber and has elasticity. The seal portion 11 is vulcanization bonded to the first support portion 21 and is integrated with the first support portion 21. The seal portion 11 has a first lip 12 that contacts the outer circumferential surface 71 of the shaft 7. The seal portion 11 further has a second lip 13 and a third lip 14. The seal portion 11 may be made of conductive rubber that has electrical conductivity.

[0020] The first lip 12 is pressed against the shaft 7 by a garter spring 15. The second lip 13 is located on the other axial side of the first lip 12 and contacts the outer peripheral surface 71 of the shaft 7. The third lip 14 is located on the other axial side of the second lip 13 and has a shape that extends to the other axial side. The third lip 14 contacts a member (not shown) located on the other axial side. These lips 12, 13, and 14 elastically deform when they come into contact with a mating member such as the shaft 7, but for the sake of explanation, the figures show them in an undeformed state.

[0021] The first support portion 21 is made of stainless steel or carbon steel (cold-rolled steel). The first support portion 21 supports the seal portion 11. The first support portion 21 has a first cylindrical portion 26 as a cylindrical portion and a first annular portion 27 as an annular portion. The first cylindrical portion 26 is attached to the inner periphery of the housing 8 in metallic contact with the housing 8. The first annular portion 27 extends from a portion 261 of the first cylindrical portion 26 in a direction toward the shaft 7.

[0022] The first cylindrical portion 26 is fitted to the inner circumferential surface 81 of the housing 8 with an interference fit. As a result, the first support portion 21 is attached to the housing 8 in a state of metal contact. The first lip 12 is provided to extend from a radially inner part 271 of the first annular portion 27 toward the shaft 7.

[0023] The second support portion 40 is made of stainless steel or carbon steel (cold-rolled steel). The second support portion 40 supports the conductive portion 30. The second support portion 40 (see FIG. 2 ) has a second cylindrical portion 46 as the cylindrical portion 41 and a second annular portion 47 as the annular portion 42. The second cylindrical portion 46 (cylindrical portion 41) is attached to the inner periphery of the first cylindrical portion 26 in metallic contact. The second annular portion 47 (annular portion 42) extends from a part 461 of the second cylindrical portion 46 (cylindrical portion 41) in a direction toward the axis 7.

[0024] The second cylindrical portion 46 is fitted onto the inner circumferential surface 262 of the first cylindrical portion 26 with an interference fit. As a result, the second support portion 40 is attached to the first support portion 21 in a state of metal contact. A curved portion 34 (described below) that is part of the conductive portion 30 is provided so as to extend from a radially inner portion 471 of the second annular portion 47 toward the shaft 7. As will be described later, the conductive portion 30 has a contact portion 31 on its radially inner side that contacts the outer circumferential surface 71 of the shaft 7. As shown in FIGS. 1 and 2 , the second support portion 40 supports the conductive portion 30, and the contact portion 31 is located on one axial side of the lip 12.

[0025] The conductive part 30 has an elastic sheet 32 ​​and a conductive sheet 33 laminated on the elastic sheet 32. The elastic sheet 32 ​​is made of rubber. The elastic sheet 32 ​​may also be made of conductive rubber. The conductive sheet 33 is made, for example, of a laminate of a carbon sheet and a resin layer. The carbon sheet is, for example, a nonwoven fabric made of carbon fiber. The conductive sheet 33 is formed by impregnating the carbon sheet with resin as a binder and curing it. The fibers of the conductive sheet 33 may also be made of other materials, such as fibers (metal fibers) made of conductive metals such as copper and nickel.

[0026] The elastic sheet 32 ​​is vulcanization molded. The conductive sheet 33 and the second support portion 40 are provided as inserts into the mold for vulcanization molding. The elastic sheet 32 ​​is molded integrally with the conductive sheet 33 and the second support portion 40. As a result, the conductive sheet 33 and the elastic sheet 32 ​​are laminated, and further, the elastic sheet 32 ​​is integrated with the second support portion 40.

[0027] The elastic sheet 32 ​​and the conductive sheet 33 are each thin sheets that are configured to conform to the shape (L-shaped cross section) of the second support portion 40. In the conductive portion 30, the elastic sheet 32 ​​is a layer on one axial side, and the conductive sheet 33 is a layer on the other axial side. The elastic sheet 32 ​​has a covering portion 36 that covers a radially inner portion 471 of the second annular portion 47 from one axial side. The covering portion 36 is provided so as to extend around and wrap around the one axial side of the portion 471 of the second annular portion 47.

[0028] Conductive portion 30, which is constituted by elastic sheet 32 ​​and conductive sheet 33, has curved portion 34 that extends from the radially inner end (portion 471) of second support portion 40 toward shaft 7 and is further curved to one axial side. Curved portion 34 is not supported by second support portion 40 and is elastically deformable. The tip end of curved portion 34 of conductive portion 30 becomes contact portion 31 that contacts outer peripheral surface 71 of shaft 7. In other words, contact portion 31 is included in the portion (curved portion 34) of conductive portion 30 that extends toward shaft 7 from radially inner portion 471 of second annular portion 47 (annular portion 42).

[0029] The surface of curved portion 34 on the other axial side, facing shaft 7, has a convex curve, and this surface (convex curve) faces conductive sheet 33. As described above, conductive sheet 33 is made by impregnating a carbon sheet with resin as a binder and then curing it, but the carbon (carbon fiber) of conductive sheet 33 is exposed. Therefore, the carbon (carbon fiber) of conductive sheet 33 is also exposed at contact portion 31. The surface of contact portion 31 where the carbon is exposed comes into direct contact with outer peripheral surface 71 of shaft 7.

[0030] The conductive portion 30 is conductive due to the presence of the conductive sheet 33. The conductive sheet 33 is conductive throughout the entire area between its radially outer end 331 and its radially inner end 332. In the case of the sealing device 10 of the first embodiment, a portion of the conductive sheet 33, including the radially outer end 331, contacts the inner circumferential surface 262 of the first cylindrical portion 26 of the first support portion 21. The other portion of the conductive sheet 33, including the radially inner end 332, is the contact portion 31 that contacts the outer circumferential surface 71 of the shaft 7.

[0031] 1 and 2 , as described above, the elastic sheet 32 ​​is vulcanization molded, and the conductive sheet 33 and the second support portion 40 are provided as insert parts in the mold for vulcanization molding. Therefore, the second support portion 40 and the conductive portion 30 become an inseparable integrated part. Therefore, the conductive block 39 including the second support portion 40 and the conductive portion 30 can be easily press-fitted into the first support portion 21.

[0032] The conductive portion 30 has high conductivity due to the conductive sheet 33. The conductive portion 30 has elasticity due to the elastic sheet 32. Therefore, the contact portion 31 of the conductive portion 30 has the ability to follow the shaft 7. A conductive path is obtained between the housing 8 and the shaft 7, passing through the first cylindrical portion 26 of the metal first support portion 21 and the conductive sheet 33 of the conductive portion 30 that contacts the first cylindrical portion 26. For example, the housing 8 is grounded, and current can flow from the shaft 7 through the conductive path, preventing charging of the equipment in which the sealing device 10 is installed.

[0033] [Another embodiment of the sealing device 10] Fig. 3 is a cross-sectional view showing another embodiment (second embodiment) of the sealing device of the present invention. The sealing device 10 shown in Fig. 3 is provided between a metal shaft 7 and a metal housing 8 surrounding the shaft 7. The sealing device 10 prevents leakage of lubricating oil inside the equipment between the shaft 7 and the housing 8. The sealing device 10 has a seal portion 11, a metal first support portion 21, a conductive portion 30, and a metal second support portion 40. The sealing device 10 shown in Fig. 3 is an oil seal having a garter spring 15. In the above respects, it is the same as the sealing device 10 of the first embodiment shown in Figs. 1 and 2.

[0034] Figure 4 is an enlarged cross-sectional view of a portion of the sealing device 10 shown in Figure 3. The configuration of the seal block 29 having the seal portion 11 and the first support portion 21 is the same in the first embodiment and the second embodiment. The configuration of the conductive block 39 having the second support portion 40 and the conductive portion 30 is different in the first embodiment and the second embodiment. Here, a description of the seal block 29 will be omitted. In the second embodiment shown in Figures 3 and 4, the same components as in the first embodiment are denoted by the same reference numerals.

[0035] The second support portion 40 has an outer support plate 43 and an inner support plate 44 that is separate from the outer support plate 43 and attached to the outer support plate 43. The outer support plate 43 and the inner support plate 44 are each made of stainless steel or carbon steel (cold-rolled steel).

[0036] The outer support plate 43 (see FIG. 4 ) has a cylindrical outer tube portion 432 and an annular outer ring portion 431. The outer tube portion 432 is attached in metal contact with the inner circumferential surface 262 of the first cylindrical portion 26, which is a cylindrical portion of the first support portion 21. The outer ring portion 431 is provided to extend from a part 432 a of the outer tube portion 432 in a direction toward the shaft 7.

[0037] The inner support plate 44 has a cylindrical inner tube portion 442 and an annular inner ring portion 441. The inner tube portion 442 is attached in metallic contact with the inner circumferential surface 432b of the outer tube portion 432. The inner ring portion 441 is provided to extend from a portion 442a of the inner tube portion 442 in a direction toward the shaft 7.

[0038] The outer cylindrical portion 432 is fitted with an interference fit to the inner circumferential surface 262 of the first cylindrical portion 26. As a result, the outer support plate 43 is attached to the first support portion 21 in a state of metal contact. The inner cylindrical portion 442 is fitted with an interference fit to the inner circumferential surface 432b of the outer cylindrical portion 432. As a result, the inner support plate 44 is attached to the outer support plate 43 in a state of metal contact.

[0039] As will be explained later, the conductive portion 30 is in the form of an annular sheet. The outer annular portion 431 is located on one axial side of the annular portion 35 of the conductive portion 30. The inner annular portion 441 is located on the other axial side of the portion 35 of the conductive portion 30, and sandwiches the portion 35 of the conductive portion 30 between itself and the outer annular portion 431. The conductive portion 30 is supported by the second support portion 40 having such an outer support plate 43 and inner support plate 44. An adhesive may also be used to support the conductive portion 30.

[0040] The conductive portion 30 has a curved portion 34 (described later) that extends from a radially inner portion of the combined outer annular portion 431 and inner annular portion 441 toward the shaft 7. As will be described later, the conductive portion 30 has a contact portion 31 on its radially inner side that comes into contact with the outer peripheral surface 71 of the shaft 7. As shown in Figures 3 and 4 , the second support portion 40 supports the conductive portion 30, and the contact portion 31 is located on one axial side of the lip 12.

[0041] The conductive part 30 has an elastic sheet 32 ​​and a conductive sheet 33 laminated on the elastic sheet 32. The elastic sheet 32 ​​is made of rubber. The elastic sheet 32 ​​may also be made of conductive rubber. The conductive sheet 33 is made, for example, of a laminate of a carbon sheet and a resin layer. The carbon sheet is, for example, a nonwoven fabric made of carbon fiber. The conductive sheet 33 is formed by impregnating the carbon sheet with resin as a binder and curing it. The fibers of the conductive sheet 33 may also be made of other materials, such as fibers (metal fibers) made of conductive metals such as copper and nickel.

[0042] The conductive portion 30 is a separate member from each of the outer support plate 43 and the inner support plate 44. In the conductive portion 30, the elastic sheet 32 ​​is a layer on one axial side, and the conductive sheet 33 is a layer on the other axial side. Therefore, the conductive sheet 33 contacts the inner annular portion 441.

[0043] Conductive portion 30, which is formed by elastic sheet 32 ​​and conductive sheet 33, has curved portion 34 that extends from the radially inner end of second support portion 40, which is formed by the combined outer annular portion 431 and inner annular portion 441, toward shaft 7 and is further curved to one axial side. Curved portion 34 is not supported by second support portion 40 and is elastically deformable. The tip end of curved portion 34 of conductive portion 30 becomes contact portion 31 that contacts outer peripheral surface 71 of shaft 7. In other words, contact portion 31 is included in a portion (curved portion 34) of conductive portion 30 that extends from a radially inner part of second support portion 40 toward shaft 7.

[0044] The surface of curved portion 34 on the other axial side, facing shaft 7, has a convex curve, and this surface (convex curve) faces conductive sheet 33. As described above, conductive sheet 33 is made by impregnating a carbon sheet with resin as a binder and then curing it, but the carbon (carbon fiber) of conductive sheet 33 is exposed. Therefore, the carbon (carbon fiber) of conductive sheet 33 is also exposed at contact portion 31. The surface of contact portion 31 where the carbon is exposed comes into direct contact with outer peripheral surface 71 of shaft 7.

[0045] The conductive portion 30 is conductive due to the presence of the conductive sheet 33. The conductive sheet 33 is conductive throughout the entire area between a radially outer end 331 and a radially inner end 332. In the case of the sealing device 10 of the second form, a portion of the conductive sheet 33 contacts the inner annular portion 441 of the inner support plate 44. The other portion of the conductive sheet 33, including the radially inner end 332, is the contact portion 31 that contacts the outer peripheral surface 71 of the shaft 7.

[0046] 3 and 4 , as described above, the second support portion 40 has the outer support plate 43 and the inner support plate 44, which are separate members. The sheet-like conductive portion 30 is a separate member from each of the outer support plate 43 and the inner support plate 44. The annular portion 35 of the conductive portion 30 is sandwiched and fixed between the outer annular portion 431 of the outer support plate 43 and the inner annular portion 441 of the inner support plate 44.

[0047] According to this configuration of the second support portion 40, when the inner support plate 44 is attached to the outer support plate 43, the part 35 of the conductive portion 30 is sandwiched between them. There is no need to integrally mold the second support portion 40 and the conductive portion 30. This makes it easier to manufacture each component.

[0048] The conductive portion 30 has high conductivity due to the conductive sheet 33. The conductive portion 30 has elasticity due to the elastic sheet 32. Therefore, the contact portion 31 of the conductive portion 30 has the ability to follow the shaft 7. A conductive path is obtained between the housing 8 and the shaft 7, passing through the first cylindrical portion 26 of the metal first support portion 21, the outer tubular portion 432 of the metal outer support plate 43, the inner tubular portion 442 of the metal inner support plate 44, and the conductive sheet 33 of the conductive portion 30. For example, the housing 8 is grounded, allowing current to flow from the shaft 7 through the conductive path, preventing static electricity from building up in the equipment in which the sealing device 10 is installed.

[0049] [Regarding the sealing device 10 of each of the above embodiments] As described above, the sealing device 10 of each of the first and second embodiments has the seal portion 11, the first support portion 21 made of metal, the conductive portion 30, and the second support portion 40 made of metal. The seal portion 11 is elastic and has the lip 12 that contacts the shaft 7. The first support portion 21 is attached to the housing 8 in a state of metal contact and supports the seal portion 11. The conductive portion 30 is conductive. The conductive portion 30 has a contact portion 31 that contacts the shaft 7. The second support portion 40 supports the conductive portion 30, and the contact portion 31 of the conductive portion 30 is located on one axial side of the lip 12. The second support portion 40 is attached to the first support portion 21 in a state of metal contact.

[0050] According to the sealing device 10 of each of the first and second embodiments, the first support portion 21 is attached to the housing 8 in a state of metal contact, the second support portion 40 is attached to the first support portion 21 in a state of metal contact, and the conductive portion 30 is supported by the second support portion 40. The conductive portion 30 has a contact portion 31 that contacts the shaft 7. With this configuration, a conductive path that passes through the conductive portion 30 is obtained between the housing 8 and the shaft 7 as a path separate from the seal portion 11.

[0051] In the first embodiment (see FIG. 2 ), first support portion 21 has a first cylindrical portion 26 in metal contact with the inner circumferential side of housing 8, and a first annular portion 27 extending from a portion 261 of first cylindrical portion 26 in a direction toward axis 7. Second support portion 40 has a second cylindrical portion 46 (cylindrical portion 41) in metal contact with the inner circumferential side of first cylindrical portion 26, and a second annular portion 47 (annular portion 42) extending from a portion 461 of second cylindrical portion 46 in a direction toward axis 7.

[0052] Lip 12 is provided to extend from radially inner part 271 of first annular portion 27 toward shaft 7. Contact portion 31 that comes into contact with shaft 7 is included in a portion (curved portion 34) of conductive portion 30 that is provided to extend from radially inner part 471 of second annular portion 47 toward shaft 7.

[0053] The second cylindrical portion 46 of the second support portion 40 is attached to the first cylindrical portion 26 of the first support portion 21, thereby obtaining a sealing device 10 in which the seal block 29 including the first support portion 21 and the seal portion 11 and the conductive block 39 including the second support portion 40 and the conductive portion 30 are integrated. When attaching this sealing device 10 to equipment, handling of the components becomes easy. Furthermore, since the second support portion 40 is positioned within the axial range of the first support portion 21, the sealing device 10 can be made smaller in the axial direction.

[0054] In the second form (see Figure 4), the first support portion 21 has a first cylindrical portion 26 that is in metal contact with the inner side of the housing 8, and a first annular portion 27 that extends from a part 261 of the first cylindrical portion 26 in a direction toward the axis 7.

[0055] In the second support portion 40, the outer cylindrical portion 432 and the inner cylindrical portion 442 overlap in the radial direction, thereby constituting a "cylindrical portion 41." The outer annular portion 431 and the inner annular portion 441 are aligned in the axial direction with the conductive portion 30 sandwiched therebetween, thereby constituting a "ring-shaped portion 42." In other words, in the second embodiment, the second support portion 40 has a "cylindrical portion 41" that is attached to the inner periphery of the first cylindrical portion 26 in a state of metallic contact, and a "ring-shaped portion 42" that extends from a part of the cylindrical portion 41 in a direction toward the axis 7.

[0056] Lip 12 is provided to extend from a radially inner part 271 of first annular portion 27 toward shaft 7. Contact portion 31 that comes into contact with shaft 7 is included in a part (curved portion 34) of conductive portion 30 that is provided to extend from a radially inner part of annular portion 42 toward shaft 7.

[0057] The cylindrical portion 41 of the second support portion 40 is attached to the first cylindrical portion 26 of the first support portion 21, thereby obtaining a sealing device 10 in which the seal block 29 including the first support portion 21 and the seal portion 11 and the conductive block 39 including the second support portion 40 and the conductive portion 30 are integrated. When attaching this sealing device 10 to equipment, handling of the components becomes easy. Furthermore, since the second support portion 40 is positioned within the axial range of the first support portion 21, the sealing device 10 can be made smaller in the axial direction.

[0058] In each of the first and second forms, the sheet-like conductive portion 30 made up of the conductive sheet 33 and the elastic sheet 32 ​​has a curved portion 34 that curves to one axial side on the shaft 7 side, and the conductive sheet 33 is kept in contact with the shaft 7. Even when one axial side across the sealing device 10 is under higher pressure than the other axial side, the conductive sheet 33 is kept in contact with the shaft 7.

[0059] In recent years, the electrification of automobiles has progressed. That is, electric motors are used as a power source for automobiles. The induced current generated by the motor can cause electromagnetic noise, which can adversely affect other electrical equipment (e.g., audio equipment). In sealing devices used in such motors, the seal portion 11 is made of conductive rubber or conductive grease is used as a countermeasure against electromagnetic noise. However, in these cases, it is difficult to achieve high conductivity.

[0060] In contrast, the sealing device 10 of the first and second embodiments of the present invention has, in addition to the first support portion 21 and second support portion 40 made of metal, a highly conductive conductive portion 30 as a portion separate from the seal portion 11. The configuration including the conductive portion 30 forms a conductive path between the grounded housing 8 (motor housing) and the shaft 7 that serves as the rotating shaft of the motor. Through this conductive path, it becomes possible for the motor current to escape from the grounded housing 8, thereby suppressing the effects of electromagnetic noise as described above.

[0061] In both the first and second embodiments, as described above, the conductive portion 30 is elastic due to the elastic sheet 32, and the contact portion 31 of the conductive portion 30 has the ability to follow the shaft 7. FIG. 5 is an explanatory diagram showing a modified example of the conductive portion 30 (second embodiment). In order to further improve the followability of the conductive portion 30 and ensure that the contact portion 31 is in contact with the shaft, a plurality of slits (notches) 37 may be provided in the tip portion 301 on the inner circumferential side (shaft side) of the conductive portion 30. The slits 37 are formed from the tip portion 301 on the inner circumferential side of the annular conductive portion 30, and a plurality of slits 37 are provided in a radial arrangement. Similarly, the conductive portion 30 of the first embodiment may also have slits 37.

[0062] [Others] The above-described embodiments are illustrative in all respects and are not limiting. The scope of the present invention is defined by the claims, not the above-described embodiments, and includes all modifications within the scope of equivalents to the configurations described in the claims.

[0063] 7 Shaft 8 Housing 10 Sealing device 11 Seal portion 12 First lip (lip) 21 First support portion 26 First cylindrical portion 261 Part of first cylindrical portion 262 Inner peripheral surface of first cylindrical portion 27 First annular portion 271 Part of first annular portion 30 Conductive portion 31 Contact portion 32 Elastic sheet 33 Conductive sheet 35 Part of conductive portion 40 Second support portion 41 Cylindrical portion 42 Annular portion 43 Outer support plate 431 Outer annular portion 432 Outer cylindrical portion 432a Part of outer cylindrical portion 432b Inner peripheral surface of outer cylindrical portion 44 Inner support plate 441 Inner annular portion 442 Inner cylindrical portion 442a Part of inner cylindrical portion

Claims

1. A sealing device provided between a metal shaft and a metal housing surrounding the shaft, comprising: a seal portion that is elastic and has a lip that contacts the shaft; a metal first support portion that is attached to the housing in metal contact and supports the seal portion; a conductive portion that is conductive and has a contact portion that contacts the shaft; and a metal second support portion that supports the conductive portion, with the contact portion located on one axial side of the lip, wherein the second support portion is attached to the first support portion in metal contact.

2. A sealing device as described in claim 1, wherein the first support portion has a first cylindrical portion attached to the inner periphery of the housing in metallic contact therewith, and a first annular portion extending from a portion of the first cylindrical portion in a direction toward the axis, the second support portion has a cylindrical portion attached to the inner periphery of the first cylindrical portion in metallic contact therewith, and an annular portion extending from a portion of the cylindrical portion in a direction toward the axis, the lip is provided extending from a portion of the first annular portion toward the axis, and the contact portion is included in a portion of the conductive portion extending from a portion of the annular portion toward the axis.

3. A sealing device according to claim 1 or claim 2, wherein the second support portion and the conductive portion are an inseparable integral part.

4. The sealing device according to claim 3, wherein the conductive portion has an elastic sheet that is integral with the second support portion and a conductive sheet that is laminated with the elastic sheet, a portion of the conductive sheet contacts the first support portion, and another portion of the conductive sheet is the contact portion that contacts the shaft.

5. A sealing device as described in claim 1 or claim 2, wherein the second support portion has an outer support plate and an inner support plate that is separate from the outer support plate and attached to the outer support plate, the outer support plate has an outer annular portion located on one axial side of a portion of the conductive portion that is in the form of a circular sheet, and the inner support plate has an inner annular portion that sandwiches a portion of the conductive portion between itself and the outer annular portion.

6. A sealing device as described in claim 5, wherein the outer support plate has a cylindrical outer tube portion attached in metallic contact with the inner circumferential surface of the cylindrical portion of the first support portion, and the outer annular portion extending from a part of the outer tube portion in a direction towards the axis, the inner support plate has a cylindrical inner tube portion attached in metallic contact with the inner circumferential surface of the outer tube portion, and the inner annular portion extending from a part of the inner tube portion in a direction towards the axis, the conductive portion having a conductive sheet and an elastic sheet laminated with the conductive sheet, the conductive sheet contacting the inner annular portion and having the contact portion contacting the axis.

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