JP6301092B2 - Corrugated cage for ball bearings and ball bearings - Google Patents

Description

  The present invention relates to a corrugated cage and a ball bearing for holding a ball of a ball bearing.

  Bearings that support planetary gears of planetary gear type automatic transmissions and rotors of electric motors of electric vehicles (EVs) or hybrid vehicles (HEVs) are large in terms of layout. Is adopted.

  These ball bearings are used in a high rotational speed region, and in order to improve fuel efficiency, a low torque bearing with reduced friction is required.

  In order to reduce the torque of the large ball bearing, for example, it is one method to employ a resin cage described in Patent Document 1. However, the lubricating oil contained in the transmission contains an extreme pressure additive, and the extreme pressure additive may cause embrittlement of the resin cage, which is not preferable for reducing the torque.

  For this reason, the corrugated cage described in Patent Document 2 is generally adopted as a cage for large ball bearings. 5 to 7 show a conventional ball bearing employing a corrugated cage, and a plurality of bearings are formed between a raceway groove 21 formed on the inner diameter surface of the outer ring 20 and a raceway groove 23 formed on the outer diameter surface of the inner ring 22. The balls 24 are incorporated, and the plurality of balls 24 are held by the waveform holder 25.

  Here, the corrugated cage 25 couples a pair of annular holding plates 26 in which ball holding portions 27 and coupling plate portions 28 are alternately provided in the circumferential direction by caulking a rivet 29 that penetrates the coupling plate portion 28. Since it is made of metal, it does not satisfy the demand for lowering the torque of ball bearings, and improvements are desired in use for electric motors in EVs and HEVs.

JP 2009-115128 A JP 2001-241449 A

  By the way, the ball bearings for electric motors required by EV and HEV are used at high speed rotation and light load. Therefore, by reducing the number of balls, the stirring resistance of the lubricating oil is reduced, so that the torque can be reduced. Can do.

  Here, the ball filling rate (ratio of the ball on the pitch circle of the bearing) in the conventional ball bearing using the corrugated cage is about 54 to 60%. The torque can be reduced by lowering the ball filling rate, but at least three balls are required to exhibit the function as a ball bearing. Since the ball filling rate in this case is 4%, the ball filling rate needs to be 4% or more, and the number of balls is preferably 5 or more in consideration of rotational accuracy and load capacity.

  On the other hand, when the ball filling rate exceeds 54%, the rotational torque increases. Therefore, by setting the ball filling rate in the range of 4 to 40%, the torque can be reduced while maintaining the function as a ball bearing. Will be.

  However, in the conventional waveform holder 25, as shown in FIG. 7, each of the plurality of coupling plate portions 28 in the pair of annular holding plates 26 is coupled by a single rivet 29, By reducing the ball filling rate, the circumferential length L of the coupling plate portion 28 is increased, and the ball 24 is delayed and advanced during the rotation of the ball bearing, so that the circumferential direction extends toward the pocket side ends of the pair of coupling plate portions 28. When a pressing force of 2 is applied, the pair of coupling plate portions 28 are deformed so as to expand outward, and the holding of the ball 24 may become unstable, and rattling may occur. Further, there is a possibility that a large load acts on the caulking portion of the rivet 29 and is damaged.

  An object of the present invention is that, in a ball bearing in which measures for reducing torque are taken by reducing the number of balls, the coupling plate portion of the corrugated cage that holds the balls is deformed outward by the pressure due to the delay or advance of the balls. Is to prevent.

  In order to solve the above problems, in the waveform holder according to the present invention, a pair of annular holding plates in which hemispherical ball holding portions and coupling plate portions along the outer periphery of the ball are alternately provided in the circumferential direction, As a combination in which the ball holding portions are opposed to each other and pockets for holding the balls are formed between the opposed portions, each of the coupling plate portions facing each other is coupled by rivet crimping, and the ball filling rate is 4 to 40% In the ball bearing corrugated cage having the above-mentioned range, a configuration is adopted in which each of the plurality of coupling plate portions facing each other is coupled by a plurality of rivets provided at intervals in the circumferential direction.

  Further, in the ball bearing according to the present invention, a plurality of balls are incorporated between the raceway groove formed on the inner diameter surface of the outer ring and the raceway groove formed on the outer diameter surface of the inner ring, and the plurality of balls are held by the cage. In the ball bearing in which the ball filling rate is in the range of 4 to 40%, the corrugated cage according to the present invention is adopted as the cage.

Here, the ball filling rate refers to the proportion of balls on the pitch circle of the ball bearing, and refers to the rate expressed by the following mathematical formula 1.
Ball filling rate = (number of balls × ball diameter) / (π × PCD) Equation 1
P.P. C. D is the pitch circle diameter of the bearing.

  In the corrugated cage according to the present invention, the annular holding plate may be made of a press-formed product of a metal plate or may be cast. Alternatively, it may be formed by cutting.

  In the present invention, as described above, each of the plurality of coupling plate portions facing each other is coupled by the plurality of rivets provided at intervals in the circumferential direction, so that the pocket-side end portion of the coupling plate portion is used. Because the distance to the coupling site by rivet caulking can be shortened, it is possible to prevent the pocket side end of the coupling plate from deforming outwards when the ball bearing rotates due to the delay or advance of the ball. In addition, the rivet caulking portion can be prevented from being damaged.

The front view of the ball bearing formed using the waveform holder concerning this invention FIG. 1 is an enlarged front view showing a part of FIG. Sectional view along line III-III in FIG. Sectional view along line IV-IV in FIG. Front view of a ball bearing formed using a conventional corrugated cage The front view which expands and shows a part of FIG. Sectional drawing along the VII-VII line of FIG.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. As shown in the figure, the ball bearing incorporates a plurality of balls 5 between a raceway groove 2 formed on the inner diameter surface of the outer ring 1 and a raceway groove 4 formed on the outer diameter surface of the inner ring 2, and the plurality of balls 5 are corrugated. It is held by the cage 10.

  Here, when the ball filling rate = (number of balls × ball diameter) / (π × bearing pitch circle diameter), the ball filling rate is set to 4 to 40%, and measures to reduce the torque are taken for the ball bearing. ing.

  The waveform holder 10 includes a pair of annular holding plates 11. The annular holding plate 11 is made of a metal plate press-formed product in which hemispherical ball holding portions 12 and coupling plate portions 13 along the outer periphery of the ball 5 are alternately provided in the circumferential direction.

  The pair of annular holding plates 11 is a combination in which the ball holding portions 12 face each other and the ball holding pockets 14 are formed between the opposed portions, and each of the coupling plate portions 13 facing each other has its coupling plate portion. The rivet 15 penetrating the rivet 13 is joined by caulking to form a waveform holder 10.

  Here, two rivets 15 for coupling the coupling plate portion 13 are made into one set, and the two rivets 15 constituting the set are provided at intervals in the circumferential direction so that the end portions close to the pocket 14 are connected to each other. Are connected. Reference numeral 16 denotes a caulking portion of the rivet 15.

  As shown in FIG. 4, as shown in FIG. 4, each of the plurality of coupling plate portions 13 facing each other is coupled by the two rivets 15 provided at intervals in the circumferential direction. Since the distance a from the end portion on the pocket 14 side to the coupling portion by the rivet 15 can be shortened, the end portion on the pocket 14 side of the coupling plate portion 13 is outside due to the delay or advance of the ball 5 when the ball bearing rotates. There is no inconvenience of deformation.

  Further, if the connecting plate portion 13 is deformed outward, a large load may be applied to the caulking portion 16 of the rivet 15 to cause damage, but the connecting plate portion 13 is not deformed outward. There is no inconvenience that the caulking portion 16 is damaged, and the corrugated cage 10 that is strong in strength and excellent in durability can be obtained.

1 outer ring 2 raceway groove 3 inner ring 4 raceway groove 5 ball 10 corrugated cage 11 annular holding plate 12 ball holding portion 13 connecting plate portion 14 pocket 15 rivet

Claims (2)

A bearing inner diameter is used for ball bearings for automobiles of 100 mm or more, and a pair of annular holding plates in which hemispherical ball holding portions and coupling plate portions along the outer periphery of the balls are alternately provided in the circumferential direction, As a combination in which the ball holding portions face each other and pockets for holding the balls are formed between the facing portions, the coupling plate portions facing each other are joined by rivet caulking, and the annular holding plate is a metal plate In the corrugated cage for ball bearings, wherein the ball filling rate represented by the following formula 1 is in the range of 4 to 40%,
Each of the plurality of coupling plates facing each other is coupled by a plurality of circumferentially spaced rivets, and the distance between the plurality of rivets is determined by the pocket-side end of the coupling plate and the end. Corrugated cage for ball bearings characterized in that it is longer than the distance between the rivet nearest to the part .
Ball filling rate = (number of balls × ball diameter) / (π × PCD) Equation 1
Here, P.I. C. D represents the pitch circle diameter of the bearing. A plurality of balls are assembled between a raceway groove formed on the inner diameter surface of the outer ring and a raceway groove formed on the outer diameter surface of the inner ring, and the plurality of balls are held by a cage. In ball bearings with a filling rate in the range of 4-40%,
A ball bearing comprising the corrugated cage according to claim 1 .
Ball filling rate = (number of balls × ball diameter) / (π × PCD) Equation 1
Here, P.I. C. D represents the pitch circle diameter of the bearing.

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