JP2007333022A - Deep groove ball bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a deep groove ball bearing equipped with a retainer made of a steel plate, wherein rotation torque of a bearing is reduced. <P>SOLUTION: The retainer 5 of the deep groove ball bearing is made by two annular retaining plates 7 formed from the steel plate by press forming, ball retaining parts 8 hemi-spherically swelling are formed at a plurality of spots provided at regular intervals in the circumferential direction of these annular retaining plates 7, these ball retaining parts 8 are made to face each other on the open side to form recessed spherical pockets 9, oil holes 11 are provided at the parts of the pocket 9 with which a ball 4 does not make contact with, and a low friction thin film 12 comprising a DLC thin film is formed at least on the surface of the pocket 9. Thereby, lubricant such as grease staying in the pocket 9 is pushed out to the outside of the pocket 9 by centrifugal force, stirring resistance is reduced, and rotation torque of the bearing is reduced. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a deep groove ball bearing that supports a rotating member such as a gear, and more particularly to a deep groove ball bearing provided with a steel plate cage that reduces the rotational torque of the bearing.

  Conventionally, a deep groove ball bearing is generally used as a rolling bearing for supporting rotating members such as motor shafts and gears of automobile transmissions in order to have a small rotational torque and exhibit desired durability against misalignment among rolling bearings. Frequently used. For this deep groove ball bearing, a steel plate cage that is easy to assemble and low in cost is conventionally used. 5 and 6 are typical examples of such cages.

  The cage 50 is formed by pressing a steel plate, and a ball 52 is sandwiched between two annular holding plates 51 and 51 so as to be able to rotate. As shown in FIG. 6A, the two annular holding plates 51 are each formed with a ball holding portion 53 that swells in a hemispherical shape at a plurality of positions at equal intervals in the circumferential direction. In addition, these two annular holding plates 51 face each ball holding portion 53 on the opening side, hold the balls 52 in the pockets 54 formed thereby, and between the ball holding portions 53. It is fixed with rivets 55.

  In this corrugated cage 50, each ball holding portion 53 of the annular holding plate 51 has a distance from the center C of the opening surface of the ball holding portion 53 that is slightly longer than the radius r of the ball 52 at the bottom. However, it is formed so that this distance becomes longer as it becomes a peripheral part. In addition, the radius of curvature of the inner peripheral surface is set to be substantially the same as or slightly larger than the radius r of the ball 52 at the bottom of the ball holding portion 53, and the radius of curvature (r + α) becomes larger toward the peripheral portion. Accordingly, since the distance from the center C of the opening surface is increased at the peripheral edge portion of the inner peripheral surface of the ball holding portion 53, the clearance with the ball 52 is increased.

Further, at the bottom of the inner peripheral surface of the ball holding portion 53, the curvature radius is substantially along the outer peripheral surface of the ball 52, so that the ball 52 can be reliably held at the center of the pocket 54. For this reason, there is no fear that the ball 52 contacts the edge of the joint of the ball holding portions 53, 53 constituting the pocket 54, and the ball 52 is formed at the bottom of the ball holding portions 53 on both sides constituting the pocket 54. Since it rotates around the axis line connecting them, the portion with the smallest peripheral speed of the ball 52 is held only by the bottom portion of the ball holding portion 53, thereby reducing the traction force.
JP 2001-241449 A

  However, in such a conventional corrugated cage 50, since the pocket 54 is formed by the ball holding portion 53 that swells in a hemispherical shape, the ball 52 rotates on the R surface of the pocket 54 while slipping. is doing. Therefore, as shown in FIG. 6B, since the ball 52 is in sliding contact with a certain contact width (contact area) S, a sliding resistance is generated between the ball 52 and the cage 50, and the rotational torque of the bearing is reduced. There were limits. Further, since the ball 52 rotates while receiving the stirring resistance of the lubricating grease staying in the pocket 54, an increase in rotational torque is unavoidable particularly in a high speed region. In recent years, for example, transmission bearings have been required to reduce torque in order to improve vehicle fuel efficiency. However, it has been a challenge to reduce the rotational torque of such bearings.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a deep groove ball bearing provided with a steel plate cage that reduces the rotational torque of the bearing.

  In order to achieve such an object, the invention according to claim 1 of the present invention includes an outer ring having an arcuate outer rolling surface formed on the inner periphery, and an arcuate inner surface facing the outer rolling surface on the outer periphery. An inner ring formed with a rolling surface, a cage disposed between the inner ring and the outer ring, and a plurality of balls accommodated between the rolling surfaces via the cage so as to roll freely. In the deep groove ball bearing, the cage is composed of two annular holding plates formed by pressing from a steel plate, and ball holding portions that bulge out at a plurality of equally spaced locations in the circumferential direction of the annular holding plate are provided. The ball holding portions are opposed to each other on the opening side to form a pocket, and an oil hole is provided at a portion where the ball is not in contact with the pocket when the ball is moved to one side of the pocket when rotating.

  In this way, in the deep groove ball bearing provided with the steel plate cage, the cage is composed of two annular holding plates formed by pressing from the steel plate, and the annular holding plates are equally spaced in the circumferential direction. A ball holding portion that bulges to a plurality of locations is formed, and these ball holding portions are opposed to each other on the opening side to form a pocket, and a portion where the ball does not come into contact with the pocket while rotating toward one side of the pocket during rotation Since the oil hole is provided in the pocket, the lubricant such as grease staying in the pocket is pushed out of the pocket by the centrifugal force, the stirring resistance is reduced, and the rotational torque of the bearing can be reduced.

  According to a second aspect of the present invention, the ball holding portion is formed to swell in a hemispherical shape, and a concave spherical pocket is formed by these ball holding portions, and both sides of the bottom portion of the ball holding portion are formed. The oil holes may be provided at two locations, and the ball holding portion bulges into a rectangular shape as in the invention according to claim 3, and is formed into a polygonal shape by these ball holding portions. And two oil holes may be provided in the vicinity of the corners of the ball holding portion.

  Further, as in the invention described in claim 4, if a low-friction thin film is formed on at least the pocket surface of the entire surface of the cage, sliding friction between the ball and the cage can be remarkably suppressed. Furthermore, the rotational torque of the bearing can be reduced.

  Further, if the ball is made of ceramic as in the fifth aspect of the invention, torque loss caused by the deformation of the ball on the rolling surfaces of the inner ring and the outer ring can be reduced.

  In addition, if the deep groove ball bearing is for an automobile transmission as in the invention described in claim 6, it can be expected that fuel efficiency is improved by reducing the rotational torque of the bearing, and minute wear powder is mixed in the lubricating oil. Even under such conditions, the wear can be suppressed and sufficient durability can be exhibited against the biting of the wear powder.

  The deep groove ball bearing according to the present invention includes an outer ring in which an arc-shaped outer rolling surface is formed on the inner periphery, and an inner ring in which an arc-shaped inner rolling surface facing the outer rolling surface is formed on the outer periphery, In a deep groove ball bearing comprising a plurality of balls that are slidably accommodated via a cage between the rolling surfaces, the cage is formed by two annular holding plates formed by pressing from a steel plate. The ball holding portion is formed and bulges at a plurality of equally spaced locations in the circumferential direction of the annular holding plate, the ball holding portions are opposed to each other on the opening side to form a pocket, and the ball is rotated during rotation. Since the oil hole is provided in a portion that does not come into contact with the pocket in a state of being close to one side of the pocket, a lubricant such as grease staying in the pocket is pushed out of the pocket by centrifugal force, and the stirring resistance is reduced. Reduced bearing rotation It is possible to reduce the torque.

  An outer ring having an arcuate outer rolling surface formed on the inner periphery, an inner ring having an arcuate inner rolling surface facing the outer rolling surface on the outer periphery, and a cage between the two rolling surfaces In a deep groove ball bearing comprising a plurality of balls accommodated so as to be able to roll through the cage, the cage is composed of two annular holding plates formed by pressing from a steel plate, and the circular holding plate has a circular shape. Ball holding portions that swell in a semispherical shape are formed at a plurality of equally spaced locations in the circumferential direction, and these ball holding portions are opposed to each other on the opening side to form a concave spherical pocket. An oil hole is provided in a portion that does not come into contact with the pocket in a state of being close to one side of the surface, and a DLC thin film is formed at least on the pocket surface.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
1 is a longitudinal sectional view showing a first embodiment of a deep groove ball bearing according to the present invention, FIG. 2 (a) is a sectional view taken along the line II-II in FIG. 1, and (b) is (a). FIG.

  The deep groove ball bearing 1 includes an outer ring 2 having an arc-shaped outer rolling surface 2a formed on the inner periphery and an inner ring formed with an arc-shaped inner rolling surface 3a facing the outer rolling surface 2a on the outer periphery. 3, a plurality of balls 4 accommodated between both rolling surfaces, a cage 5 that holds these balls 4 in a freely rolling manner, and seals 6, 6 attached to both ends of the outer ring 2. A predetermined type of lubricating grease is sealed inside the bearing to constitute a sealed deep groove ball bearing 1.

  The outer ring 2, the inner ring 3 and the ball 4 are made of high carbon chrome bearing steel such as SUJ2, and are hardened in the range of 58 to 64 HRC to the core part by quenching. On the other hand, the cage 5 is formed by subjecting a strip steel such as a cold rolled steel plate (JIS standard SPCC system or the like) to plastic processing such as press working or drawing.

  As shown in FIG. 2 (a), the cage 5 is configured such that the ball 4 is sandwiched between two annular holding plates 7 and 7 so as to be able to rotate. Each of the two annular holding plates 7 and 7 is formed with a ball holding portion 8 that swells in a hemispherical shape at a plurality of equally spaced locations in the circumferential direction. In addition, these two annular holding plates 7 and 7 are configured such that the ball holding portions 8 and 8 are opposed to each other on the opening side, and the balls 4 are held in the concave spherical pockets 9 formed thereby. The ball holding portions 8 and 8 are fixed with rivets 10.

  In this cage 5, the radius of curvature of the pocket 9 is slightly larger than the radius of the ball 4. And the oil hole 11 is provided in the site | part which the ball | bowl 4 of the pocket 9 does not contact. In other words, the ball holding portion 8 is provided at two positions on both sides of the bottom portion. As a result, the lubricating grease staying in the pocket 9 is pushed out of the pocket 9 by the centrifugal force, and the stirring resistance is reduced, so that the rotational torque of the bearing can be reduced.

  Here, in this embodiment, the low friction thin film 12 is formed on at least the pocket 9 surface of the entire surface of the cage 5. Typical examples of the material of the low friction thin film 12 include hard ceramic thin films such as a DLC (diamond-like carbon) film, a boron nitride film, and a carbon nitride film.

  The DLC film is a film containing carbon as a main component, and a film containing carbon or carbon and hydrogen as a main component, and a metal or semimetal such as Ti, Si, Cr, or W added thereto. There are a nonequilibrium sputtering method and a plasma CVD method. Boron nitride has a slightly higher coefficient of friction than DLC. On the other hand, the carbon nitride film is a film mainly composed of carbon containing nitrogen at a high concentration, and is known as an abrasion resistant film having a low friction coefficient comparable to that of DLC. Thus, by forming the low friction thin film 12 made of a low friction hard ceramic thin film on at least the pocket 9 surface of the cage 5, the sliding friction between the ball 4 and the cage 5 can be remarkably suppressed, and the bearing The rotational torque can be further reduced, and the wear resistance can be remarkably improved.

  The low friction thin film 12 formed on the surface of the cage 5 can be exemplified by a Teflon (registered trademark) thin film in addition to the hard ceramic thin film described above. The temperature rise due to sliding of the ball 4 can be suppressed as much as possible, and the cost can be reduced.

  Furthermore, in this embodiment, the ball 4 is formed of ceramic. As a result, torque loss (hysteresis loss) generated by deformation of the balls 4 on the rolling surfaces of the inner and outer rings (not shown) can be reduced, and the rotational torque of the bearing can be further reduced. In particular, under conditions where minute wear powder is mixed in the lubricating oil, such as automobile transmission bearings, wear can be suppressed and sufficient durability against wear powder biting. Can be demonstrated.

  FIG. 3 is a longitudinal sectional view showing a second embodiment of the deep groove ball bearing according to the present invention, FIG. 4A is a sectional view taken along the line IV-IV in FIG. 3, and FIG. FIG. Note that this embodiment is basically different from the first embodiment described above only in the configuration of the cage, and other parts having the same parts or the same functions are denoted by the same reference numerals and are described in detail. Is omitted.

  The deep groove ball bearing 13 includes an outer ring 2 in which an arc-shaped outer rolling surface 2a is formed on the inner periphery, and an inner ring in which an arc-shaped inner rolling surface 3a facing the outer rolling surface 2a is formed on the outer periphery. 3, a plurality of balls 4 accommodated between both rolling surfaces, and a holder 14 that holds these balls 4 so as to roll freely. The deep groove ball bearing 13 constitutes an oil-lubricated open type deep groove ball bearing 13 for use in an automobile transmission.

  The cage 14 is formed by subjecting a steel strip such as a cold rolled steel plate (JIS standard SPCC system or the like) to plastic working such as press working or drawing. As shown in FIG. 4A, the retainer 14 is obtained by sandwiching the ball 4 between two annular retaining plates 15 and 15 so as to be able to rotate. Each of the two annular holding plates 15, 15 is formed with a ball holding portion 16 that bulges in a rectangular shape at a plurality of positions at equal intervals in the circumferential direction. Further, these two annular holding plates 15, 15 constitute a substantially hexagonal pocket 17 with the ball holding portions 16 facing each other on the opening side. The balls 4 are held in the pockets 17 and the ball holding portions 16 are fixed by the rivets 10.

  Each ball holding portion 16 is formed such that the distance L between the opposing surfaces is slightly larger than the diameter 2 r of the ball 4. That is, a predetermined pocket clearance 2 e is provided in the pocket 17. Then, the inner peripheral surface of the pocket 17 having a flat surface makes point contact with the ball 4 so that the cage 14 is guided to the rolling elements. As a result, the contact width S with the ball 4 can be reduced as much as possible as compared with the conventional corrugated cage, and the sliding resistance between the ball 4 and the cage 14 is suppressed to reduce the rotational torque of the bearing. be able to.

  Here, an oil hole 11 is provided in a portion of the pocket 17 where the ball 4 does not contact. In other words, two portions are provided in the vicinity of the corner portion of the ball holding portion 16. As a result, the oil staying in the pocket 17 is pushed out of the pocket 17 by centrifugal force, the stirring resistance is reduced, and the rotational torque of the bearing can be reduced. Although the shape of the hexagonal pocket 17 is illustrated here, the present invention is not limited to this, and the cage 14 according to the present invention has a flat surface in which the inner peripheral surface of the pocket 17 is in point contact with the ball 4. Any rectangular shape may be used. For example, an octagonal shape may be used.

  Further, as in the embodiment described above, a low friction thin film 12 made of a low friction hard ceramic thin film such as a DLC film or a Teflon (registered trademark) thin film is formed on at least the pocket 17 surface of the entire surface of the cage 14. Thereby, the sliding friction of the ball | bowl 4 and the holder | retainer 14 can be suppressed significantly, and the reduction of the rotational torque of a bearing can be aimed at further. In addition, the ball 4 is formed of ceramic, so that the rotational torque of the bearing can be reduced and wear of the ball 4 and the cage 14 can be suppressed even if minute wear powder is mixed in the lubricating oil.

  The embodiment of the present invention has been described above, but the present invention is not limited to such an embodiment, and is merely an example, and various modifications can be made without departing from the scope of the present invention. Of course, the scope of the present invention is indicated by the description of the scope of claims, and further, the equivalent meanings described in the scope of claims and all modifications within the scope of the scope of the present invention are included. Including.

  The deep groove ball bearing according to the present invention can be applied to, for example, a deep groove ball bearing provided with a steel plate cage used in a transmission or the like.

It is a longitudinal section showing a 1st embodiment of a rolling bearing concerning the present invention. (A) is the II-II arrow directional cross-sectional view of FIG. (B) is the principal part enlarged view of (a). It is a longitudinal cross-sectional view which shows 2nd Embodiment of the rolling bearing which concerns on this invention. (A) is the IV-IV sectional view taken on the line of FIG. (B) is the principal part enlarged view of (a). It is a longitudinal cross-sectional view which shows the conventional cage for deep groove ball bearings. FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 5.

Explanation of symbols

1, 13 ... Deep groove ball bearing 2 ... Outer ring 2a ... Outer rolling surface 2b ... Inner diameter 3 ... · Inner ring 3a ······ Inner rolling surface 4 ······································ 5 ... Ring retaining plates 8, 16 ... Ball holding parts 9,17 ... Pocket 10 ... Rivets 11 ... Oil holes 12 ...・ ・ ・ Low friction thin film C ・ ・ ・ ・ ・ ・ ・ ・ Center L of the opening surface of the ball holding portion ・ ・ ・ ・ ・ ・ ・ ・ Distance r between opposing surfaces of the ball holding portion ・ ・ ・ ・ ・ ・ ・ ・Ball radius S ... Contact width α ... Radius of curvature

Claims (6)

An outer ring having an arcuate outer raceway formed on the inner circumference;
An inner ring in which an arc-shaped inner rolling surface facing the outer rolling surface is formed on the outer periphery;
A cage disposed between the inner ring and the outer ring;
In the deep groove ball bearing comprising a plurality of balls accommodated so as to be freely rollable between the rolling surfaces via the cage,
The cage is composed of two annular holding plates formed by pressing from a steel plate, and ball holding portions are formed to bulge at a plurality of equally spaced locations in the circumferential direction of the annular holding plate. The deep groove ball is characterized in that a portion is opposed to the opening side to form a pocket, and an oil hole is provided at a portion where the ball is not in contact with the pocket when the ball is close to one side of the pocket when rotating. bearing.   The ball holding portion is formed to swell in a hemispherical shape, and a concave spherical pocket is formed by these ball holding portions, and two oil holes are provided on both sides of the bottom portion of the ball holding portion. Item 10. The deep groove ball bearing according to item 1.   The ball holding portion is formed to bulge out in a rectangular shape, and a polygonal pocket is formed by these ball holding portions, and two oil holes are provided in the vicinity of corner portions of the ball holding portion. Item 10. The deep groove ball bearing according to item 1.   The deep groove ball bearing according to any one of claims 1 to 3, wherein a low friction thin film is formed on at least a pocket surface of the entire surface of the cage.   The deep groove ball bearing according to claim 1, wherein the ball is made of ceramic.   The deep groove ball bearing according to any one of claims 1 to 5, wherein the deep groove ball bearing is for an automobile transmission.

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