JP4855761B2 - Rolling bearing - Google Patents

Description

  The present invention relates to a rolling bearing, and more particularly to a railway vehicle main motor bearing having an insulating layer on a raceway.

  Conventionally, cylindrical roller bearings and deep groove ball bearings have been used as bearings used in railway vehicle main motors. For example, a cylindrical roller bearing 1 as shown in FIG. 5 maintains an interval between an inner ring 2, an outer ring 3, a cylindrical roller 4 as a rolling element disposed between the inner ring 2 and the outer ring 3, and the cylindrical roller 4. And a cage 5.

  As shown in FIG. 5, the cylindrical roller bearing 1 used for a railway vehicle main motor has insulating layers 3 a formed on the outer diameter surface and both end surfaces of the outer ring 3 in order to prevent damage to the bearing due to electrolytic corrosion. Yes. The insulating layer 3a is formed by spraying an insulating material such as ceramics.

  In addition, since the railway vehicle main motor is used outdoors, there is a concern that grease may deteriorate due to dust contamination in an open type bearing in which a grease pocket is formed in the bearing peripheral structure. Therefore, the cylindrical roller bearing 11 as shown in FIG. 6 is a sealed bearing in order to prevent deterioration of grease due to mixing of dust and extend a maintenance cycle.

In the conventional cylindrical roller bearing 1 shown in FIG. 5, the roller and roller length _{L 1} of 4, and the axial width _{W 1} of the inner ring 2 and outer ring _3, L 1 / _{W 1} ≧ 0.4, i.e. For bearings in which the roller length L ₁ occupies a large proportion of the axial width W ₁ , the bearing volume V ₁ and the internal space volume C ₁ are C ₁ / V ₁ ≈0.2, and the roller 4 roller The diameter A ₁ and the bearing thickness dimension T ₁ are generally designed within the range of 0.25 ≦ A ₁ / T ₁ ≦ 0.55.

In the present specification, the “bearing volume” refers to the volume of the portion surrounded by the inner ring inner diameter surface, the outer ring outer diameter surface, and the end surfaces of the inner and outer rings of the bearing. the outer diameter D _1, the inner diameter d ₁ of the inner ring 2, the axial width W _1, is calculated by the following equation by using the pi [pi.

  In the present specification, the “internal space volume” refers to the volume of a static space in which the rolling elements and the cage do not pass during rotation of the bearing among the spaces surrounded by the inner ring, the outer ring, and the hermetic seal.

For cylindrical roller bearings in the above range, since the bearing inner space volume C ₁ is small, a problem that can not be encapsulated with an appropriate amount of grease to ensure a bearing life required bearing railcar main electric motor is there. This problem also applies to ball bearings.

In the case of a ball bearing, when the ball diameter A ₂ and the axial width W ₂ of the inner and outer rings are A ₂ / W ₂ ≧ 0.4, the bearing volume V ₂ and the inner space volume C ₂ is C ₂ / V ₂ ≈0.3, and the ball diameter A ₂ and the bearing thickness dimension T ₂ are designed within the range of 0.4 ≦ A ₂ / T ₂ ≦ 0.6. It is common.

  As a means to solve the above problem, it is conceivable to increase the filling ratio of the grease with respect to the internal space volume. In this case, however, the agitation resistance of the grease increases at the time of rotation of the bearing, particularly at the start, and the temperature of the bearing rapidly increases. Is not appropriate.

  Therefore, in a sealed bearing, a cylindrical roller bearing capable of securing an appropriate amount of grease inside the bearing is described in, for example, Japanese Patent Application Laid-Open No. 2003-13971 (Patent Document 1).

As shown in FIG. 6, the cylindrical roller bearing 11 described in the publication includes an inner ring 12 having a long axial width, an outer ring 13, a cylindrical roller 14 disposed between the inner ring 12 and the outer ring 13, and a cylinder. A cage 15 that holds the gap between the rollers 14 and a hermetic seal 16 having an L-shaped cross-sectional shape that encloses grease inside the bearing are provided. The hermetic seal 16 covers the cored bar 16a with an insulating resin 16b. An insulating layer is formed on the outer diameter surface and both end surfaces of the outer ring 13.
JP 2003-13971 A

  When the cylindrical roller bearing 1 shown in FIG. 5 is fixed to the housing 7, a predetermined shoulder height h is required as shown in FIG. Therefore, when the cylindrical roller bearing 1 is small, the lower end of the housing 7 and the outer ring 3 are in contact with each other beyond the portion of the outer ring 3 covered with the insulating layer 3a.

  At this time, the creeping distance between the outer ring 3 and the housing 7 becomes the thickness δ of the insulating layer 3a at the lower end 3b of the insulating layer 3a, and is very small. Since the outer ring 3 and the housing 7 are conductors such as metal or the like, when a certain voltage or more is applied from the housing 7 to the insulating layer 3a, creeping discharge is generated along the lower end 3b of the insulating layer 3a, and the cylindrical roller bearing 1 May be damaged by electric corrosion.

  In the present specification, the “creeping distance” refers to the minimum distance along the surface of the insulating member sandwiched between two conductors. Further, in this specification, “creeping discharge” refers to a phenomenon of discharging along the surface of an insulator when a voltage of a certain level or higher is applied to the insulating member.

  Moreover, since the hermetic seal 16 of the cylindrical roller bearing 11 as shown in FIG. 6 includes a highly conductive mandrel 16a in order to maintain the L-shaped cross-sectional shape, the insulation performance of the entire bearing may be reduced. There is.

SUMMARY OF THE INVENTION An object of the present invention is to provide a rolling bearing that can enclose a sufficient amount of grease inside the bearing , prevent electric corrosion of the bearing due to creeping discharge, etc., and is excellent in insulation. It is.

The rolling bearing according to the first invention includes an outer ring, an inner ring, a rolling element disposed in a gap between the outer ring and the inner ring, a resin sealing member that is attached to the outer ring and protrudes toward the inner ring to seal the gap. In the rolling bearing having the outer ring, the inner ring, and the grease enclosed in the bearing inner space surrounded by the sealing member, and the insulating layer which is a coating formed from the end surface of the outer ring to the outer diameter surface, the sealing member is the outer ring. The edge part of the end surface of an insulating layer is covered with the surface which is attached to and protrudes toward the outer diameter side and inclines .

With the above configuration, it is possible to secure a sufficient creeping distance of the insulating layer in a portion where the outer ring and the housing are in contact, it is possible to prevent the electrolytic corrosion of the bearing according to creeping discharge or the like. Therefore, even when used for a railway vehicle main motor or the like, damage to the bearing due to electrolytic corrosion can be prevented .

As an embodiment, the sealing member is insulated by the sealing member mounting portion attached to the outer ring, and a portion fitted into the recess in the end face of the outer ring extends axially in terms of projecting inclined from the portion toward the outer diameter side and having a portion covering the edge of the end face of the layer.

The present invention can secure a bearing internal space in which a sufficient amount of grease can be sealed, and can obtain a rolling bearing excellent in insulation by securing a sufficient creepage distance between the housing and the outer ring. it can.

  With reference to FIG. 1, the cylindrical roller bearing 21 which concerns on one Embodiment of this invention is demonstrated.

  The cylindrical roller bearing 21 includes an inner ring 22 as a bearing ring, an outer ring 23 as a bearing ring having the same axial width as the inner ring 22, and a cylindrical roller 24 as a rolling element disposed between the inner ring 22 and the outer ring 23. A retainer 25 that holds the interval between the cylindrical rollers 24, and sealing seals 26 at both ends of the inner ring 22 and the outer ring 23.

  As shown in FIG. 2, an insulating layer 23 a is formed on the outer diameter surface and both end surfaces of the outer ring 23. The insulating layer 23a is formed by spraying an insulating material such as ceramics, and the bearing internal space is filled with grease.

The hermetic seal 26 is attached to the outer ring 23 so as to cover a part of the insulating layer 23a with the hermetic seal attaching part 26a. Further, when the cylindrical roller bearing 21 mounted on the housing 27, the creepage distance between the outer race 23 and the housing 27 becomes [delta] _1. In addition, from the viewpoint of preventing creeping discharge, δ ₁ is desirably ₁ mm or more.

  With the above configuration, a sufficient creepage distance can be ensured at the portion where the outer ring 23 and the housing 27 are in contact with each other, so that the electrolytic corrosion of the bearing due to creeping discharge or the like can be prevented.

  Conventionally, the seal 26 is generally made of a metal or a metal core bar covered with an insulating member such as rubber, but a resin seal is preferably used. By using the resin hermetic seal 26 that does not contain a highly conductive metal, it is possible to prevent the insulation performance of the cylindrical roller bearing 21 from being deteriorated.

  Next, a rolling bearing 31 according to another embodiment of the present invention will be described with reference to FIG.

  The cylindrical roller bearing 31 includes an inner ring 32, an outer ring 33 having the same axial width as the inner ring 32, a cylindrical roller 34 as a rolling element disposed between the inner ring 32 and the outer ring 33, and the interval between the cylindrical rollers 34. A cage 35 to be held, and a sealing seal 36 as a sealing member that does not protrude from the end face are provided at both ends of the inner ring 32 and the outer ring 33. Further, an insulating layer is formed on the outer diameter surface and both end surfaces of the outer ring 33, and the hermetic seal 36 covers a part of the insulating layer.

Furthermore, the bearing volume V ₃ of the roller bearing and the internal space volume C ₃ of the rolling bearing are set in a range of 0.24 ≦ C ₃ / V ₃ ≦ 0.30. In the embodiment shown in FIG. 3, by extending the axial width of the inner ring 32 and outer ring 33, to obtain an internal space volume C ₃ within the above range.

By the above structure, sealed with the effect of preventing the deterioration of insulation performance can be obtained, by an internal space volume C ₃ of the cylindrical roller bearing 31 is set to the above range, an appropriate amount of grease in the bearing It becomes possible to do. As a result, it is possible to obtain a roller bearing with excellent lubrication performance and extended maintenance cycle.

If C ₃ / V ₃ <0.24, it is not possible to ensure a sufficient internal space volume C ₃ for enclosing an appropriate amount of grease. On the other hand, when C ₃ / V ₃ > 0.30, the grease filled in a position far from the center of the bearing does not contribute to the lubrication of the bearing, which is meaningless from the viewpoint of improving the lubrication performance.

  Next, a rolling bearing 41 according to another embodiment of the present invention will be described with reference to FIG.

  The cylindrical roller bearing 41 has an inner ring 42, an outer ring 43 having the same axial width as the inner ring 42, a cylindrical roller 44 as a rolling element disposed between the inner ring 42 and the outer ring 43, and the interval between the cylindrical rollers 44. A retainer 45 to be held, and a sealing seal 46 as a sealing member projecting from both end faces of the inner ring 42 and the outer ring 43 in a substantially U-shaped cross-sectional shape. In addition, an insulating layer is formed on the outer diameter surface and both end surfaces of the outer ring 43, and the sealing seal 46 covers a part of the insulating layer.

  In this specification, the “substantially U-shaped” is not limited to the U-shaped shape such as the sealing seal 46 shown in FIG. Any shape that protrudes from this part is included.

In the cylindrical roller bearing 41 having the above-described configuration, the roller length L ₄ of the roller 44 and the axial width W ₄ of the inner ring 42 and the outer ring 43 are set within a range of L ₄ / W ₄ ≧ 0.4. The bearing volume V ₄ of the roller bearing 41 and the internal space volume C ₄ of the cylindrical roller bearing 41 are set in a range of 0.25 ≦ C ₄ / V ₄ ≦ 0.55.

Further, an internal space volume C ₄ to set within the above range, for example, a roller diameter A ₄ of the roller 44, and a projecting amount B ₄ from the end face of the inner ring 42 and outer ring 43 of the sealing seal 46, 0 .15 ≦ B ₄ / A ₄ ≦ 1.0 may be set.

The significance of the upper limit value and the lower limit value of the numerical range is the same as that of the cylindrical roller bearing 31. Also, for L ₄ / W ₄ <0.4, that is, for a bearing in which the ratio of the roller length L ₄ of the roller 44 to the axial width W ₄ of the bearing is small, an appropriate amount of grease can already be enclosed. In this embodiment, it is excluded from the subject of the invention.

By the above structure, it is possible to prevent a reduction in insulation performance, by an internal space volume C ₄ of the cylindrical roller bearing 41 is set to the above range, encapsulating an appropriate amount of grease in the bearing It becomes possible. As a result, it is possible to obtain a roller bearing with excellent lubrication performance and extended maintenance cycle.

  Further, since the amount of grease that can be sealed can be adjusted by the protruding amount of the hermetic seal 46, standard products can be used for the inner ring 42 and the outer ring 43. As a result, the cost increase of the cylindrical roller bearing 41 can be suppressed.

  In each of the above embodiments, an example of a cylindrical roller bearing having an outer layer on the outer diameter surface and both end surfaces of the outer ring has been shown. However, the present invention is not limited thereto, and an insulating layer is formed on the inner diameter surface and both end surfaces of the inner ring. It is good as well. Since the inner ring inner surface has a smaller spray area than the outer ring outer surface, the thermal spraying cost can be reduced by spraying the insulating layer onto the inner ring inner surface.

  In each of the above embodiments, an example of a cylindrical roller bearing has been shown. However, the present invention is not limited to this, but a tapered roller bearing, a self-aligning roller bearing, a deep groove ball bearing, a four-point contact ball bearing, an angular ball bearing, Regardless of whether the rolling element is a roller or a ball, it can be applied to any rolling bearing.

For example, in the case of a ball bearing having the same basic configuration as that of the cylindrical roller bearing 31 shown in FIG. 2 and using balls as rolling elements, the internal space volume is C ₅ , in order to allow an appropriate amount of grease to be sealed. If the volume and _{V 5,} is set within a range of _{0.32 ≦ C 5 / V 5 ≦} 0.40.

The basic configuration and the cylindrical roller bearing 41 shown in FIG. 4 is the same, if a ball bearing having balls as rolling elements, in order to enable enclosing a suitable amount of grease, the interior space volume C _6, bearing volume Is V ₆ , the ball diameter is A ₆ , and the axial width of the inner and outer rings is W ₆ , 0.35 ≦ C ₆ / V ₆ ≦ 0.55 when A ₆ / W ₆ ≧ 0.4. Set within the range.

Further, as means for setting the internal space volume C ₆ within the above range, for example, the ball diameter A ₆ and the protruding amount B ₆ from the end faces of the inner ring and the outer ring of the seal seal are set to 0.1 ≦ B ₆ It may be set within the range of / A ₆ ≦ 0.6.

  As mentioned above, although embodiment of this invention was described with reference to drawings, this invention is not limited to the thing of embodiment shown in figure. Various modifications and variations can be made to the illustrated embodiment within the same range or equivalent range as the present invention.

  The present invention is advantageously used for rolling bearings used in railway vehicle main motors and the like.

It is a cylindrical roller bearing which concerns on one Embodiment of this invention, Comprising: It is a figure which shows the state in which the sealing seal has covered the insulating layer. It is an enlarged view of the Q section of FIG. It is a cylindrical roller bearing which concerns on other embodiment of this invention, Comprising: It is a figure which shows the bearing which expanded the axial direction width | variety of the inner and outer ring. It is a cylindrical roller bearing which concerns on other embodiment of this invention, Comprising: It is the figure which made the seal seal the U-shaped cross-sectional shape which protrudes from both ends of a bearing. It shows a rolling bearing using standard products for inner ring, outer ring and hermetic seal. It is a figure which shows the rolling bearing which enlarged the axial direction width | variety of the inner ring | wheel compared with the outer ring | wheel, and enlarged the bearing internal space. It is an enlarged view of the P section in FIG.

Explanation of symbols

  1, 11, 21, 31, 41 Cylindrical roller bearing, 2, 12, 22, 32, 42 Inner ring, 3, 13, 23, 33, 43 Outer ring, 3a, 23a, 33a, 43a Insulating layer, 3b Lower end of insulating coating, 4, 14, 24, 34, 44 Cylindrical roller, 5, 15, 25, 35, 45 Cage, 6, 16, 26, 36, 46 Seal seal, 6a, 26a Seal seal mounting part, 16a Core metal, 16b Insulation Resin, 7, 27 housing.

Claims (2)

Outer ring,
Inner ring,
A rolling element disposed in a gap between the outer ring and the inner ring,
A resin sealing member attached to the outer ring and projecting toward the inner ring to seal the gap;
Grease sealed in a bearing internal space surrounded by the outer ring, the inner ring, and the sealing member;
In a rolling bearing having an insulating layer that is a coating formed from the end surface of the outer ring to the outer diameter surface,
The rolling bearing according to claim 1, wherein the sealing member covers an edge of the end surface of the insulating layer with a surface attached to the outer ring and protruding toward the outer diameter side and inclined . The sealing member is a sealing member mounting portion that is mounted on the outer ring, and extends in the axial direction and fits into a recess in the end surface of the outer ring, and an end surface of the insulating layer that protrudes from the portion toward the outer diameter side and is inclined. The rolling bearing according to claim 1, further comprising a portion covering an edge of the rolling bearing.

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