Bearing seal

Abstract

[Problem] To facilitate the manufacturing of a bearing seal that prevents electrolytic corrosion of a rolling bearing. [Solution] A bearing seal 1 is used in a rolling bearing and includes an annular seal ring 2. The seal ring 2 includes a core 3 including a portion 3B in contact with an outer ring 11, and an elastic body 4 joined to a surface, on the width direction outer side BO, of the core 3. The elastic body 4 includes an inner diameter lip portion 7 that extends toward an outer peripheral surface 12A of an inner ring 12 and that inclines to the width direction outer side BO with proximity to the outer peripheral surface 12A. The bearing seal is provided with a conductive material 5 which is held by being sandwiched at an inner diameter section D that is between the core 3 and the elastic body 4 and that extends in a substantially radial direction R. The conductive material 5 includes a portion in contact with the inner ring 12, and a form in a state before being attached to the rolling bearing is an annular shape positioned in substantially the same plane. In a state of being mounted to the rolling bearing, the conductive material 5 pressed by the restoring force of the elastically deformed inner diameter lip portion 7 contacts the inner ring 12.

Description

bearing seal

[0001] The present invention relates to a bearing seal that prevents electrolytic corrosion of a rolling bearing.

[0002] For example, current may leak into the rotating shaft in motors and reduction gear units of electric vehicles, as well as inverter-driven motors other than those for electric vehicles. In such cases, the lubricating oil film in the rolling bearing supporting the rotating shaft may be broken, causing current to flow between the outer and inner rings, resulting in arc damage to the rolling surfaces of the rolling elements.

[0003] As a bearing seal for preventing electrolytic corrosion of such rolling bearings, there is one provided with a conductive material for providing electrical continuity between the outer ring and the inner ring (see, for example, Patent Documents 1 and 2).

[0004] The bearing seal (sealing material A) in Patent Document 1 has a structure in which an elastic body B and a reinforcing material 2 are provided, and an electrically conductive material 3, which is an electrically conductive material, is embedded (FIG. 1) or attached (FIG. 2) to the elastic body B, and the electrically conductive material 3 is connected to a fitting portion A1 that fits onto the outer ring 1b and a sliding contact portion A2 that makes sliding contact with the inner ring 1a. The electrically conductive material 3 is a wire, plate, foil, or the like.

[0005] The bearing seal (seal assembly 04) in Patent Document 2 has a structure in which a seal 05 is made up of an elastomer body 08 and a reinforcing material 09, and a circular conductive element 14 made of the conductive material is affixed to the seal 05, with the outer diameter side of the conductive element 14 contacting the outer ring 02 and the inner diameter side of the conductive element 14 sliding against the inner ring 03 (FIG. 1). The conductive element 14 is made by embedding a conductive fiber fabric made of carbon fiber, a carbon fiber derivative, metal fiber, or filled polymer fiber in an elastomer matrix, i.e., a conductive elastomer.

[0006] In the seal assembly 04, the conductive element 14 is located on the opposite side (outward in the width direction) from the space to be sealed within the rolling bearing, and the radial outer and inner peripheral portions of the conductive element 14 are inclined outward in the width direction of the rolling bearing.

[0007] Japanese Patent Application Laid-Open No. 62-106125 U.S. Patent No. 11,493,133

[0008] In the case of the bearing seal (FIG. 1) in Patent Document 1, which has a structure in which an electrically conductive material such as a wire, plate or foil is embedded in an elastic body, it is difficult to manufacture the electrically conductive material so that it penetrates the elastic body in the radial direction and protrudes from a predetermined position on the elastic body to ensure sliding contact with the inner ring.

[0009] In the case of the bearing seal ( FIG. 2 ) in Patent Document 1, which has a structure in which an electrically conductive material such as a wire, plate or foil is attached to an elastic body, the electrically conductive material needs to be attached along the shape of the bearing seal, which has a relatively complex shape, and the electrically conductive material needs to be connected so as to come into contact with the outer ring and the inner ring, making manufacturing difficult.

[0010] In the case of a bearing seal as in Patent Document 2, which has a structure in which the outer diameter side and inner diameter side of a conductive elastomer come into contact with the outer ring and inner ring, the conductive elastomer must be attached to the shape of the bearing seal, which has a relatively complex shape, and the conductive elastomer must be connected so as to come into contact with the outer ring and inner ring, making manufacturing difficult.

[0011] In the case of a bearing seal having a structure in which a conductive elastomer slides against the inner ring, as in Patent Document 2, the carbon fibers, etc. embedded in the elastomer are affected by the state of dispersion within the elastomer, resulting in high conductive resistance, and in the presence of a lubricant (grease, oil, etc.), an oil film forms on the sliding surface between the conductive elastomer and the inner ring, making contact between the conductive elastomer and the inner ring unstable for conducting electricity.

[0012] In the bearing seal of Patent Document 2, the conductive material is located on the opposite side (outer side in the width direction) from the space to be sealed inside the rolling bearing, and the outer and inner radial peripheral portions of the conductive material are inclined outward in the width direction. Therefore, there are cases where the conductive material protrudes outward in the width direction beyond the end faces of the rolling bearing in the width direction, which limits the rolling bearings that can use this bearing seal.

[0013] An object of the present invention is to facilitate the manufacture of a bearing seal that prevents electrolytic corrosion in rolling bearings, and to reduce electrical resistance and improve electrical stability in the bearing seal.

[0014] A bearing seal according to a first aspect of the present invention is a bearing seal including an annular seal ring for use in a rolling bearing including an outer ring, an inner ring, and rolling elements. The seal ring has a core metal having a portion that contacts the outer ring, and an elastic body joined to the outer surface of the core metal in the width direction. The elastic body has an inner diameter lip portion that extends toward the outer peripheral surface of the inner ring and inclines outward in the width direction as it approaches the outer peripheral surface. A conductive material is provided that is sandwiched and held between the core metal and the elastic body in the inner diameter portion that extends in the approximately radial direction. The conductive material has a portion that contacts the inner ring, and its shape before being mounted on the rolling bearing is annular and located in approximately the same plane. When mounted on the rolling bearing, the conductive material is pressed by the restoring force of the elastically deformed inner diameter lip portion and comes into contact with the inner ring.

[0015] A bearing seal according to a second aspect of the present invention is a bearing seal including an annular seal ring for use in a rolling bearing including an outer ring, an inner ring, and rolling elements. The seal ring has a core metal having a portion that contacts the outer ring, and an elastic body joined to the outer surface of the core metal in the width direction. The elastic body has an inner diameter lip portion that extends toward the outer peripheral surface of the inner ring and inclines outward in the width direction as it approaches the outer peripheral surface. The inner diameter lip portion is a contact or non-contact type seal. A conductive material is provided that is sandwiched and held between the core metal and the elastic body in the inner diameter portion that extends in the approximately radial direction. The conductive material has a portion that contacts the inner ring, and its shape before being mounted on the rolling bearing is annular and located in approximately the same plane. The elastic body has an attachment portion joined to the outer surface of the conductive material in the width direction. When mounted on the rolling bearing, the conductive material is pressed by the restoring force of the elastically deformed attachment portion and comes into contact with the inner ring.

[0016] According to the configuration of the bearing seal according to the first or second aspect, the core metal contacts the outer ring of the rolling bearing, and the conductive material held between the core metal and the elastic body contacts the inner ring of the rolling bearing, thereby establishing electrical conduction between the outer ring and the inner ring. Before the bearing seal is mounted on the rolling bearing, the conductive material has an annular shape located in approximately the same plane. Therefore, it is not necessary to connect the conductive material along a seal ring having a relatively complex shape. Furthermore, because the conductive material has the annular shape before the bearing seal is mounted on the rolling bearing and has a short radial length, manufacturing the conductive material is easy. Furthermore, the conductive material is held sandwiched between the core metal and the elastic body in an inner diameter portion extending approximately in the radial direction. From the above, manufacturing a bearing seal consisting of the core metal, the elastic body, and the conductive material is easy.

[0017] A bearing seal according to a third aspect of the present invention is the bearing seal according to the first or second aspect, wherein the conductive material is a circular ring of conductive fabric or nonwoven fabric, a circular metal foil, or a circular conductive felt formed by entangling the conductive fabric itself.

[0018] In the configuration of the bearing seal pertaining to the third aspect, the conductive material is the conductive fibers molded into an annular shape, an annular metal foil, or an annular conductive felt molded by entangling the conductive fibers themselves, and is not a conductive elastomer. Therefore, electrical resistance between the conductive material and the inner ring is reduced, and an oil film is not formed on the sliding surfaces of a conductive elastomer and the inner ring in the presence of a lubricant, resulting in stable contact for electrical conduction.

[0019] As described above, the bearing seal according to the first or second aspect of the present invention facilitates the manufacture of a bearing seal that prevents electrolytic corrosion in rolling bearings. Furthermore, the configuration of the bearing seal according to the third aspect of the present invention reduces electrical resistance between the conductive material and the inner ring and stabilizes contact for electrical conduction.

[0020] FIG. 2 is an enlarged longitudinal sectional view of a main portion of a rolling bearing equipped with a bearing seal according to an embodiment of the present invention. FIG. 3 is an enlarged longitudinal sectional view of a main portion showing the periphery of one of the bearing seals in the rolling bearing of FIG. 1. FIG. 4 is a cross-sectional end view showing the shape of the bearing seal before it is incorporated into the rolling bearing. FIG. 5 is an enlarged longitudinal sectional view of a main portion of a rolling bearing equipped with a bearing seal of a first modified example. FIG. 6 is an enlarged longitudinal sectional view of a main portion of a rolling bearing equipped with a bearing seal of a second modified example. FIG. 7 is a cross-sectional end view showing the shape of the bearing seal of the second modified example before it is incorporated into the rolling bearing. FIG. 8 is an enlarged longitudinal sectional view of a main portion of a rolling bearing equipped with a bearing seal of a third modified example. FIG. 9 is a cross-sectional end view showing the shape of the bearing seal of the third modified example before it is incorporated into the rolling bearing.

[0021] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0022] In this specification, the direction parallel to the direction of the central axis of rotation of the rolling bearing is referred to as the "width direction" (see, for example, arrow B in Figure 1), and the direction perpendicular to the direction of the central axis of rotation is referred to as the "radial direction" (see, for example, arrow R in Figure 1).

[0023] In this specification, the width direction approaching the widthwise center of the rolling bearing (symbol C in Figure 1) is referred to as the "widthwise inward" (see, for example, arrow BI in Figure 1), the width direction moving away from the widthwise center is referred to as the "widthwise outward" (see, for example, arrow BO in Figure 1), the radial direction approaching the rotational center axis is referred to as the "radial direction inward" (see, for example, arrow RI in Figure 1), and the radial direction moving away from the rotational center axis is referred to as the "radial direction outward" (see, for example, arrow RO in Figure 1).

[0024] 1 includes an outer ring 11, an inner ring 12, rolling elements 13, a cage 14, and a bearing seal 1. The rolling elements 13 roll between the raceway surfaces of the outer ring 11 and the inner ring 12. The cage 14 guides the rolling elements 13 at a predetermined interval and holds them rotatably.

[0025] 1 and 2, the bearing seal 1 includes an annular seal ring 2 and a conductive material 5. The seal ring 2 has an annular core 3 made of, for example, steel, and an annular elastic body 4 made of a rubber material. The elastic body 4 is bonded to the outer surface BO of the core 3 in the width direction. The conductive material 5 is electrically connected to the core 3 and the inner ring 12.

[0026] (Core) The core 3 is a plate material and comprises an inner diameter portion 3A, an outer diameter portion 3B, and an annular portion 9A, an inner connecting portion 9B, and an outer connecting portion 9C located between the inner diameter portion 3A and the outer diameter portion 3B. The inner diameter portion 3A and the outer diameter portion 3B are annular in shape extending approximately in the radial direction R. The inner connecting portion 9B has a truncated conical side surface connecting the inner diameter portion 3A and the annular portion 9A, and the outer connecting portion 9C has a truncated conical side surface connecting the outer diameter portion 3B and the annular portion 9A. The outer surface BO in the width direction of the inner diameter portion 3A faces the conductive material 5.

[0027] (Elastic body) The elastic body 4 comprises an attachment portion 6, an inner diameter lip portion 7, an inner diameter portion 8A, an outer diameter engaging portion 8B, and an annular portion 10A, an inner connecting portion 10B, and an outer connecting portion 10C located between the inner diameter portion 8A and the outer diameter engaging portion 8B. The inner diameter portion 8A and the outer diameter engaging portion 8B are annular in shape extending substantially in the radial direction R. The inner connecting portion 10B has a truncated conical side surface that connects the inner diameter portion 8A and the annular portion 10A, and the outer connecting portion 10C has a truncated conical side surface that connects the outer diameter engaging portion 8B and the annular portion 10A.

[0028] The attachment portion 6 is thin and joined to the conductive material 5. The widthwise inward surface BI of the inner diameter portion 8A faces the conductive material 5. The inner diameter lip portion 7 protrudes from the end of the inner diameter portion 8A on the radially inward RI side. The inner diameter lip portion 7 inclines outward in the widthwise direction BO as it approaches the outer peripheral surface 12A of the inner ring 12 (as it moves radially inward RI). The outer diameter engagement portion 8B engages with the engagement groove 11A of the outer ring 11. With the outer diameter engagement portion 8B of the elastic body 4 engaged with the engagement groove 11A of the outer ring 11, the outer diameter portion 3B of the core 3 contacts the outer ring 11.

[0029] (Conductive Material) The conductive material 5 is sandwiched and held between the inner diameter portion 3A of the core 3 and the inner diameter portion 8A of the elastic body 4, i.e., in the inner diameter portion D extending approximately in the radial direction R between the core 3 and the elastic body 4, and has an inner diameter side end portion 5A that is a portion that contacts the inner ring 12. An outer diameter side end 5B, which is the end portion on the radially outer RO side of the conductive material 5, is located at the end on the radially outer RO side of the inner diameter portion 3A of the core 3 and the end on the radially inner RI side of the inner connecting portion 9B of the core 3. Therefore, the conductive material 5 can be easily positioned with respect to the core 3.

[0030] The conductive material 5 is a circular ring of conductive cloth or nonwoven fabric, a circular metal foil, or a circular felt made by entangling conductive fibers. The conductive fibers may be carbon fibers or metal-coated synthetic fibers. The metals used to coat the synthetic fibers include copper, silver, and / or nickel. Carbon fibers can be reinforced by mixing them with polyester resin, polyvinyl chloride resin, or the like.

[0031] The conductive material 5 of the bearing seal 1 is not a conductive elastomer, but is made of cloth-like or nonwoven conductive fibers molded into a circular ring, a circular metal foil, or a circular conductive felt made by entangling the conductive fibers themselves. This reduces electrical resistance between the conductive material 5 and the inner ring 12, and stabilizes contact for electrical conduction because no oil film is formed, as occurs on the sliding surfaces of a conductive elastomer and the inner ring in the presence of a lubricant.

[0032] [Shape of the conductive material before the bearing seal is mounted on the rolling bearing] Before the bearing seal 1 is mounted on the rolling bearing A, as shown in the cross-sectional end view of Figure 3, the conductive material 5 has an annular shape located in approximately the same plane including the radial direction R. Therefore, it is not necessary to connect the conductive material 5 along the seal ring 2, which has a relatively complex shape. Furthermore, because the conductive material 5 has the annular shape before the bearing seal 1 is mounted on the rolling bearing A and its length in the radial direction R is short, manufacturing the conductive material 5 is easy. Furthermore, the conductive material 5 is held in a state sandwiched between the core 3 and the elastic body 4 in the inner diameter portion D, which extends approximately in the radial direction R. From the above, manufacturing the bearing seal 1, which is composed of the core 3, the elastic body 4, and the conductive material 5, is easy.

[0033] [Installation of bearing seal on rolling bearing] When installing the bearing seal 1 on the rolling bearing A (Fig. 1) from the state shown in Fig. 3 as shown in Fig. 2, the conductive material 5 in contact with the widthwise end face 12B of the inner ring 12 is deformed so as to bend. As a result, as shown in Fig. 2, the radially inward RI portion of the conductive material 5 is inclined toward the widthwise outward RO as it moves toward the radially inward RI, and the inner diameter side end 5A of the conductive material 5 comes into contact with the outer peripheral surface 12A of the inner ring 12. The attachment portion 6 and inner diameter lip portion 7 of the elastic body 4 press the conductive material 5 in an elastically deformed state, so that the contact of the conductive material 5 with the inner ring 12 is stable.

[0034] When the bearing seal 1 is mounted on the rolling bearing A in this manner, the outer diameter engaging portion 8B of the elastic body 4 is engaged with the engaging groove 11A of the outer ring 11, and the outer diameter portion 3B of the core 3 is in contact with the outer ring 11. Therefore, the core 3 of the bearing seal 1 comes into contact with the outer ring 11, and the conductive material 5 held between the core 3 and the elastic body 4 comes into contact with the inner ring 12, so that the outer ring 11 and the inner ring 12 are electrically connected.

[0035] [Modifications] (First Modification) The portion of the core bar 3 that contacts the outer ring 11 may be an engagement portion 3C as shown in the cross-sectional view of Fig. 4. That is, in the example of Fig. 4, the engagement portion 3C provided at the end of the core bar 3 on the radially outward RO side engages with the engagement groove 11A of the outer ring 11, so that the core bar 3 contacts the outer ring 11. The elastic body 4 in the bearing seal 1 of Fig. 4 does not have the outer diameter engagement portion 8B shown in Fig. 2, nor does it have the annular portion 10A. Note that the annular portion 10A may be provided in the example of Fig. 4.

[0036] (Second variant) The bearing seal 1 shown in the cross-sectional view of Figure 5 and the cut-away end view of Figure 6 shows an example in which the attachment portion 6 of the elastic body 4 is eliminated from the example shown in the cross-sectional view of Figure 2 and the cut-away end view of Figure 3.

[0037] When the bearing seal 1 is mounted on the rolling bearing A (FIG. 1) from the state shown in FIG. 6 as shown in FIG. 5, the conductive material 5 in contact with the widthwise end face 12B of the inner ring 12 is deformed so as to bend. As a result, as shown in FIG. 5, the radially inward RI portion of the conductive material 5 is inclined toward the widthwise outward RO as it moves toward the radially inward RI, and the inner diameter side end 5A of the conductive material 5 comes into contact with the outer peripheral surface 12A of the inner ring 12. The inner diameter lip portion 7 of the elastic body 4 fits against the widthwise outward BO surface of the conductive material 5, and the inner diameter lip portion 7 presses the conductive material 5 in an elastically deformed state, so that the contact of the conductive material 5 with the inner ring 12 is stable.

[0038] (Third Variant) The bearing seal 1 shown in the cross-sectional view of Figure 7 and the cut-away end view of Figure 8 shows an example in which the inner diameter lip portion 7 of the elastic body 4 and the conductive material 5 are spaced apart from each other in the example shown in the cross-sectional view of Figure 2, so that the conductive material 5 is not pressed by the inner diameter lip portion 7.

[0039] When the bearing seal 1 is mounted on the rolling bearing A (FIG. 1) from the state shown in FIG. 8 as shown in FIG. 7, the conductive material 5 in contact with the widthwise end face 12B of the inner ring 12 is deformed so as to bend. As a result, as shown in FIG. 7, the radially inward RI portion of the conductive material 5 is inclined toward the widthwise outward RO as it moves toward the radially inward RI, and the inner diameter side end 5A of the conductive material 5 comes into contact with the outer peripheral surface 12A of the inner ring 12. The attachment portion 6 of the elastic body 4 is joined to the widthwise outward BO surface of the conductive material 5, and the attachment portion 6 presses the conductive material 5 with mainly the base portion 6A of the attachment portion 6 elastically deforming, so that the contact of the conductive material 5 with the inner ring 12 is stable.

[0040] In the example of the bearing seal 1 shown in Figure 7, the inner lip portion 7 forms a contact-type seal, but it may also be a non-contact-type seal in which the tip 7A of the inner lip portion 7 is separated from the outer peripheral surface 12A of the inner ring 12.

[0041] The above description of the embodiments is given by way of example only and is not intended to be limiting, and various improvements and modifications can be made without departing from the scope of the present invention.

[0042] DESCRIPTION OF SYMBOLS 1 Bearing seal 2 Seal ring 3 Core metal 3A Inner diameter portion 3B Outer diameter portion (portion in contact with outer ring) 3C Engagement portion (portion in contact with outer ring) 4 Elastic body 5 Conductive material 5A Inner diameter side end portion (portion in contact with inner ring) 5B Outer diameter side end 6 Attachment portion 6A Root portion 7 Inner diameter lip portion 7A Tip 8A Inner diameter portion 8B Outer diameter engagement portion 9A Annular portion 9B Inner connecting portion 9C Outer connecting portion 10A Annular portion 10B Inner connecting portion 10C Outer connecting portion 11 Outer ring 11A Engagement groove 12 Inner ring 12A Outer peripheral surface 12B Width direction end face 13 Rolling element 14 Cage A Rolling bearing B Width direction BI Width direction inner side BO Width direction outer side C: Width direction center D: Inner diameter portion extending approximately in the radial direction between the core metal and the elastic body R: Radial direction RI: Radial inward RO: Radial outward

Claims

1. A bearing seal including an annular seal ring for use in a rolling bearing which includes an outer ring, an inner ring and rolling elements, wherein the seal ring has a core bar having a portion which contacts the outer ring, and an elastic body joined to the widthwise outer surface of the core bar, the elastic body having an inner diameter lip portion which extends toward the outer peripheral surface of the inner ring and which inclines outward in the width direction as it approaches the outer peripheral surface, and a conductive material is sandwiched and held in the inner diameter portion which extends approximately radially between the core bar and the elastic body, the conductive material has a portion which contacts the inner ring, and its shape before being mounted on the rolling bearing is annular and located in approximately the same plane, and when mounted on the rolling bearing, the conductive material is pressed by the restoring force of the elastically deformed inner diameter lip portion and comes into contact with the inner ring.

2. A bearing seal including an annular seal ring for use in a rolling bearing including an outer ring, an inner ring, and rolling elements, wherein the seal ring has a core bar having a portion in contact with the outer ring, and an elastic body joined to the widthwise outer surface of the core bar, the elastic body having an inner diameter lip portion extending toward the outer peripheral surface of the inner ring and inclining outward in the width direction as it approaches the outer peripheral surface, the inner diameter lip portion being a contact or non-contact type seal, and comprising a conductive material sandwiched and held in an inner diameter portion extending approximately radially between the core bar and the elastic body, the conductive material having a portion in contact with the inner ring, and having a shape that is approximately in the same plane before being attached to the rolling bearing, the elastic body having an attachment portion joined to the widthwise outer surface of the conductive material, and when attached to the rolling bearing, the conductive material is pressed by the restoring force of the elastically deformed attachment portion and comes into contact with the inner ring.

3. A bearing seal as claimed in claim 1 or 2, wherein the conductive material is a circular ring of conductive fabric or non-woven fabric, a circular metal foil, or a circular conductive felt formed by entangling the conductive fabric.

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