JP2007232188A - Roller bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a roller bearing wherein spacers are laid between adjacent rollers, the spacers having improved strength. <P>SOLUTION: The roller bearing comprises the plurality of rollers 6 rollingly laid between an inner ring raceway surface and an outer ring raceway surface, and the spacers 8 located between the adjacent rollers 6. The spacers 8 have expansion portions 8b at both axial ends, facing roller end faces 6b. On the cross sections of the spacers 8 perpendicular to the circumferential direction of the bearing, the roots of the expansion portions 8b are evenly connected to each other. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a roller bearing in which a spacer is interposed between rolling elements instead of a cage.

Patent Document 1 discloses a roller bearing in which a spacer is interposed between adjacent rollers. In this type of roller bearing, more rollers can be incorporated in the bearing, and a high load capacity can be obtained. However, the roller bearing described in Patent Document 1 inevitably restricts the movement of the spacer by the raceway surface and the collar side surface of the inner ring and the outer ring, so that the spacer is necessarily the same size as the radial cross section of the roller. Therefore, there is a tendency that the stirring resistance of the lubricating oil is large. Furthermore, since the spacer is slid on the raceway surface and the collar side surface of the inner ring or the outer ring, smooth oil film formation on the rolling surface and the collar side surface may be impaired.
Japanese Patent No. 3549530

  In order to eliminate the above-described problems of the roller bearing described in Patent Document 1, the present applicant previously described in FIG. 7 in the roller bearing in which the spacer is interposed between the rollers, the axial direction of the spacer. It has been proposed to restrict the movement of the spacer in the axial direction by providing extended portions with surfaces facing the roller end surfaces at both ends (Japanese Patent Application No. 2005-253746). By adopting such a configuration, the movement of the spacer in the axial direction can be restricted by the end portion of the expansion portion, and the movement in the radial direction can be restricted by the roller rolling surface or the inner ring collar outer diameter or outer ring collar. It can be regulated by the inner diameter. That is, since the inner ring and outer ring raceway surfaces and flange side surfaces are not used as spacer movement restricting means, there is no need to interpose the spacer over a wide area between adjacent rollers, and the stirring resistance of the lubricating oil can be suppressed. Also, oil film formation on the rolling surface and the collar side surface is not hindered. Further, when the spacer is guided to the inner ring collar outer diameter or the outer ring collar inner diameter, the expansion portion also exerts an effect of expanding the guide area, so that an oil film is easily formed on the guide surface.

  A main object of the present invention is to improve the strength of a spacer in a roller bearing in which a spacer is interposed between adjacent rollers.

  The roller bearing according to the present invention is a roller bearing having a plurality of rollers rotatably interposed between an inner ring raceway surface and an outer ring raceway surface, and a spacer between adjacent rollers. And an extended portion facing the roller end face, and the base of the extended portion is connected flush with a cross section perpendicular to the bearing circumferential direction of the spacer. By adopting such a configuration, the probability of breakage of the spacer can be reduced. That is, stress concentration can be avoided by not providing a step at the base of the extension on the upper surface or the lower surface of the spacer. In other words, it is possible to reduce the number of corners that are the starting point of stress concentration in the spacer.

For example, when the extended portion is formed as shown in FIG. 7, stress concentrates on the corners of the upper and lower surfaces. In addition to the compressive stress in the circumferential direction of the bearing, bending stress to the extension may act on the spacer. That is, since the spacer has a degree of freedom in the circumferential clearance of the bearing, the posture of the spacer may be disturbed, and a force may act on the extended portion from the roller end face. In particular, when the corner is located in the vicinity of the thin portion of the spacer, there is a possibility that a crack may occur at the base of the extended portion starting from the corner.

  According to a second aspect of the present invention, in the roller bearing according to the first aspect, at least one of the surfaces of the expansion portion of the spacer which is peeled from the inner side or the outer side in the radial direction of the bearing is formed by an inclined surface. is there. By adopting such a configuration, it is possible to reduce the agitation resistance of the lubricating oil during the operation of the bearing while avoiding the occurrence of the stress concentration, and the roller rolling surface and the sliding portion of the spacer Heat generation in can be reduced. That is, by extending the gradient of the expansion portion toward the center of the spacer in the axial direction, it is not necessary to extend the expansion portion from the inner diameter side of the spacer to the outer diameter side. The size can be reduced, and the stirring resistance of the lubricating oil can be reduced. Moreover, since the contact length between the roller rolling surface and the spacer can be shortened by extending the gradient shape, heat generation can be reduced, and further, the rotational torque of the bearing can be reduced. Further, since the area where the spacer covers the roller rolling surface is reduced, the cooling efficiency by the lubricating oil can be improved.

このような構成を採用することで、ころ端面から間座の拡張部に加わる力を大幅に軽減することができる。すなわち、円周方向すきまの中で傾こうとする間座の動きを、拡張部ところ端面によって規制するのではなく、間座ところ転動面の接触によって規制することで、拡張部に作用する力を小さくすることができる。すなわち、間座が傾いた状態で軸受の回転が急加減速されても、間座は容易に軸方向に逃げることができる。 According to a third aspect of the present invention, in the roller bearing of the first or second aspect, the clearance Sa between the extended portion and the end surface of the spacer is S, the circumferential clearance is L, the roller length is Lw, and the extended portion length of the spacer is When the maximum value of L is L, it is within the range represented by Formula 1.

By adopting such a configuration, it is possible to greatly reduce the force applied to the expansion portion of the spacer from the roller end face. In other words, the movement of the spacer that is about to tilt in the circumferential clearance is not restricted by the end face of the extension, but by the contact of the rolling face of the spacer, the force acting on the extension Can be reduced. That is, even if the rotation of the bearing is suddenly accelerated or decelerated while the spacer is tilted, the spacer can easily escape in the axial direction.

  According to a fourth aspect of the present invention, in the roller bearing of any one of the first to third aspects, the spacer is formed by injection molding of a synthetic resin, and only one gate is provided in the spacer. is there. By adopting such a configuration, it is possible to avoid the occurrence of a weld portion and to avoid a local strength decrease. When the spacer is a through-hole, the occurrence of welds is basically unavoidable, but the occurrence of welds can be limited to one place by adopting a one-point gate.

  According to a fifth aspect of the present invention, in the roller bearing of the fourth aspect, the gate is arranged on a surface of the spacer facing the inner side or the outer side in the radial direction of the bearing. By adopting such a configuration, the flow direction of the resin is orthogonal to the contact line direction between the roller and the spacer, and the crushing strength of the spacer can be improved.

  In general, an injection-molded product has a lower strength in the direction perpendicular to the flow direction of the resin, and this tendency appears more prominently in resin materials containing fibers. In particular, when receiving a line load along the direction of the fiber, the effect of fiber reinforcement cannot be obtained sufficiently. Here, the spacer receives a compressive force through line contact of the roller rolling surface during operation of the bearing. Therefore, the crushing strength can be improved by making the flow direction of the resin in the spacer perpendicular to the contact line direction of the spacer. In terms of the crushing strength, it is desirable to provide a gate over the entire contact position of the spacer and make the direction of compressive force to the spacer and the flow direction of the resin the same. There is a problem with slidability with the moving surface, which is not realistic.

  According to the present invention, in a roller bearing in which a spacer is interposed between adjacent rollers, the probability of breakage of the spacer can be reduced. Further, the stirring resistance of the lubricating oil during the operation of the bearing can be reduced, and heat generation on the roller rolling surface and the sliding surface of the spacer can be reduced.

  Embodiments of the present invention will be described below with reference to the drawings.

  First, for convenience, a cylindrical roller bearing as an example of a roller bearing will be described with reference to FIG. 2. The cylindrical roller bearing includes an inner ring 2, an outer ring 4, a cylindrical roller 6, and a spacer 8. The cylindrical roller 6 can roll between the raceway surface of the inner ring 2 and the raceway surface of the outer ring 4, and a spacer 8 is interposed between the adjacent cylindrical rollers 6. The spacer 8 is generally plate-shaped, and has a surface that contacts the rolling surface 6a of the cylindrical roller 6, that is, a roller contact surface 8a, on both surfaces thereof. At both ends in the longitudinal direction of the spacer 8, extended portions 8 b having surfaces facing the roller end surface 6 b of the cylindrical roller 6 are formed.

  The embodiment shown in FIG. 1 is an example in which the upper and lower surfaces including the extended portion 8a of the spacer 8 are formed linearly, that is, flush with each other. As shown in the figure, since no step (corner) is formed at the base of the extension portion 8a except in the extension direction, concentration of stress can be avoided.

  The embodiment shown in FIG. 3 is an example in which the upper surface of the spacer 8 is formed in a straight line including the extended portion 8b, that is, in the same plane, and the lower surface of the extended portion 8a is formed as a slope. In this case, the slope extends in a straight line, that is, flush with the roller contact surface 8a. In other words, the gradient is the same from the region of the extended portion 8b to the region of the roller contact surface 8a. By adopting such a configuration, the lower corner portion of the extended portion 8b is cut compared to the extended portion having a rectangular cross section, and the lower corner portions of both ends of the roller contact surface 8a are also cut. In addition to reducing the agitation resistance of the lubricating oil, the contact length between the rolling surface 6a of the roller 6 and the spacer 8 is shortened to reduce heat generation. In FIG. 3, the gradient shape is connected to the vertical surface via a gentle arc, but the gradient shape may be extended to the lowermost surface of the spacer 8.

In FIG. 4, the movement of the spacer 8 to be inclined in the circumferential clearance of the bearing is not restricted by the extended portion 8 b and the end face 6 b but by the contact of the spacer 8 and the rolling surface 6 a. This shows the state, and the force applied from the roller end face 6b to the extended portion 8b of the spacer 8 can be greatly reduced. For example, the internal specifications of the cylindrical roller bearing NJ2324E (φ120 × φ260 × 86) shown in FIG. 2 are as follows: circumferential clearance S = 1.5 mm, roller length Lw = 62 mm, spacer extension portion length L = 20 mm. Therefore, the clearance Sa between the extended portion 8b of the spacer 8 and the end surface 6b should be 0.53 mm or more. If this is expressed by a formula, it is as shown in Formula 1.

  FIG. 5 shows a resin spacer 8 formed by injection molding, and an injection-molded gate 10 is arranged at one position on the lower surface of the spacer 8, in other words, the surface facing the inside in the radial direction of the bearing. Here, in order to reduce the flow resistance of the lubricating oil, the lower center of the spacer 8 is notched as indicated by reference numeral 8c, and the gate 10 is provided on the lower surface of the notch. Since the spacer 8 does not have a portion in which the resin material is divided into two, such as a through hole, for example, a weld portion is not generated by setting the gate 10 to one location.

  Further, since the gate 10 is arranged on the lower surface of the spacer 8, the flow direction of the resin in the spacer 8 is orthogonal to the contact line direction with the spacer 8 and 6. Will improve. FIG. 6 shows a case where the gate 10 is arranged at the end of the spacer 8 for comparison. In this case, as indicated by the arrows, the flow direction of the resin is parallel to the contact line direction between the spacers 8 and 6, which is not desirable from the viewpoint of the crushing strength of the spacers 8. It should be noted that the gate 10 should be provided at a position that avoids contact with other components, and is preferably provided at a place that is not conspicuous when assembled in the bearing. Both ends are removed for the reasons described above in connection with FIG. 6 and the roller contact surface 8a is removed for contact with the roller 6, so that the lower surface (FIG. 5) or upper surface of the spacer 8 is the gate 10 It can be said that it is suitable for installation. These are the surfaces facing inward or outward in the radial direction of the bearing.

(A) is the front view of the spacer which shows an Example, (B) is a perspective view. Broken perspective view of a roller bearing showing another embodiment Front view of the spacer in the bearing of FIG. Plan view showing rollers adjacent to each other via a spacer A perspective view of a spacer showing another embodiment A perspective view of a spacer showing a comparative example (A) is a broken perspective view of a roller bearing, (B) is a front view of a spacer in the bearing of FIG. 7 (A).

Explanation of symbols

2 Inner ring 4 Outer ring 6 Cylindrical roller 6a Rolling surface 6b Roller end surface 8 Spacer 8a Roller contact surface 8b Expansion portion 8c Notch 10 Gate

Claims (5)

  In a roller bearing having a plurality of rollers movably interposed between an inner ring raceway surface and an outer ring raceway surface, and a spacer between adjacent rollers, the spacer has an extension portion facing the roller end surface at both axial ends. A roller bearing characterized in that the base of the extension portion is connected flush with each other in a cross section perpendicular to the bearing circumferential direction of the spacer.   The roller bearing according to claim 1, wherein at least one of the surfaces of the extension portion facing the inner side or the outer side in the radial direction of the bearing is formed as a slope. When the circumferential clearance is S, the roller length is Lw, and the maximum length of the extended portion of the spacer is L, the clearance Sa between the extended portion and the end surface of the spacer is within the range of Formula 1. Item 1 or 2 roller bearing.

  4. The roller bearing according to claim 1, wherein the spacer is formed by injection molding of a synthetic resin, and only one gate is provided in the spacer.   The roller bearing according to claim 4, wherein the gate is arranged on a surface of the spacer facing the inner side or the outer side in the radial direction of the bearing.

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