JP2006077950A - Rolling bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rolling bearing capable of inhibiting the generation of noise at low temperature by securing lubricating performance at low temperature without changing blending proportion of grease. <P>SOLUTION: This deep groove ball bearing 1 comprises an outer ring 2 having an outer ring raceway groove 2a on its inner peripheral face, an inner ring 3 having an inner ring raceway groove 3a on its outer peripheral face, and a plurality of balls 4 rotatably retained between the outer ring raceway groove 2a and the inner ring raceway groove 3a, and the grease 8 is sealed therein. The percentage of radius of curvature R of the inner ring raceway groove 3a to a diameter D of the ball 4 is 51.5-55%, and the percentage of a groove depth H of the inner ring raceway groove 3a to the diameter D of the rolling element 4 is 18.5-21%. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a rolling bearing, and more particularly to a rolling bearing used for an engine accessory such as an alternator.

  An engine accessory such as an alternator uses an engine as a drive source, and a transmission member such as an endless belt is wound between a drive pulley fixed to the crankshaft of the engine and a driven pulley fixed to the rotation shaft of the engine accessory. It is hung and driven. An engine accessory such as an alternator may be used under severe conditions of −40 ° C. to −30 ° C. in a cold region. Under such a low temperature condition, it is incorporated into an engine accessory such as an alternator. Due to the deterioration of the lubrication performance of the grease enclosed in the rolling bearing and the high contact surface pressure due to the high belt load, etc., the wear vibration between the raceway surface of the rolling bearing and the ball that is the rolling element differs. Sound may be generated.

As a conventional technique for preventing the generation of abnormal noise at low temperatures, a base oil composed of at least one of a synthetic hydrocarbon oil and a phenyl ether oil and having a kinematic viscosity at 40 ° C. of 15 to 90 mm ² / sec, and an increase composed of a urea compound. It is known to improve the acoustic characteristics at low temperature by securing lubricating performance at low temperature by enclosing a rolling bearing with grease containing hardener and difficult to soften and controlling viscosity. (For example, refer to Patent Document 1).
JP 2001-146596 A

  However, assuming that the grease is used under low temperature conditions and the grease viscosity emphasizes the characteristics at low temperatures (especially fluidity), the grease fluidity may become excessive at high temperatures, and grease leakage may occur. There was a possibility of causing problems such as In particular, rolling bearings used in engine accessories such as alternators are often used with grease based on ether-based oil because performance at high temperatures is also required. However, such as -40 ° C to -30 ° C If fluidity at low temperature is ensured, there is a possibility that viscosity at high temperature may be insufficient, and there is room for improvement.

  The present invention has been made in view of the above-described problems, and the object thereof is to ensure the lubricating performance at low temperatures and suppress the generation of abnormal noise at low temperatures without changing the blending of grease. It is to provide a rolling bearing.

  In order to achieve the above-described object, the rolling bearing according to the present invention is characterized by the following (1) and (2).

(1) It is rotatably arranged between a fixed ring, a rotating ring, and a fixed ring raceway groove and a rotating ring raceway groove respectively provided on the circumferential surfaces facing each other of the fixed ring and the rotating ring. A rolling bearing comprising a plurality of balls,
The ratio of the radius of curvature of the rotating ring raceway groove to the diameter of the ball is 51.5% to 55%, and the ratio of the groove depth of the rotating ring raceway groove to the diameter of the ball is 18.5% to 21%. %.

(2) In the rolling bearing according to (1) above,
Grease with ether base oil is enclosed.

  According to the rolling bearing having the above-described configuration (1), the ratio of the radius of curvature of the rotating ring raceway groove to the diameter of the ball that is the rolling element is 51.5% to 55%, and the rotating ring raceway groove to the ball diameter. The ratio of the groove depth is 18.5% to 21%, and the radius of curvature of the rotating ring raceway groove and the relationship between the groove depth and the ball diameter are optimized. As a result, the inflow of grease to the contact portion between the rotating ring raceway groove and the ball and the vicinity of the contact portion is improved, and the grease flowing into the contact portion and the vicinity of the contact portion is effectively used. The lubrication performance is improved and the generation of abnormal noise at low temperatures is suppressed.

  According to the rolling bearing having the configuration (2), grease having an ether base oil is enclosed, so that it has excellent lubrication performance at high temperature and high lubrication performance in a wide temperature range from high temperature to low temperature. Secured.

  According to the rolling bearing of the present invention, the relationship between the radius of curvature and the groove depth of the rotating ring raceway groove is optimized, so that the lubrication performance at low temperature can be ensured without changing the blending of grease. It is possible to provide a rolling bearing capable of suppressing occurrence of abnormal noise at the time.

  The present invention has been briefly described above. Furthermore, the details of the present invention will be further clarified by reading through the best mode for carrying out the invention described below with reference to the accompanying drawings.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a longitudinal sectional view of a deep groove ball bearing according to an embodiment of the present invention, FIG. 2 is an enlarged view of a main part showing the relationship between the balls and the inner ring raceway grooves in FIG. 1, and FIG. FIG. 4 is a graph showing the relationship between the groove depth of the inner ring raceway groove and the abnormal noise at low temperature.

  As shown in FIGS. 1 and 2, the deep groove ball bearing 1 has an outer ring 2 having an outer ring raceway groove 2a formed on the inner peripheral surface, and an inner ring 3 having an inner ring raceway groove 3a formed on the outer peripheral surface. ing. Between the outer ring raceway groove 2a and the inner ring raceway groove 3a, a plurality of balls 4 which are rolling elements are arranged at equal intervals in the circumferential direction and are held by a cage 5 so as to be freely rollable. An annular seal 6 is disposed at both ends of the outer ring 2 in the axial direction. The inner space defined between the outer ring 2 and the inner ring 3 is sealed, and the grease 8 sealed in the inner space is provided. Prevents leakage to the outside. The grease 8 sealed in the internal space is also sufficiently filled in the space 10 that is a gap defined between the inland track groove 3 a and the ball 4. Both the raceway surfaces of the outer ring raceway groove 2a and the inner ring raceway groove 3a and the rolling surface of the ball 4 are lubricated by the grease 8, so that the outer ring 2 and the inner ring 3 rotate relatively smoothly.

  The grease 8 incorporated in the engine accessory such as an alternator and sealed in the deep groove ball bearing 1 that requires lubrication performance under a relatively high temperature condition is preferably one having an ether base oil. Accordingly, various additives such as thickeners, extreme pressure agents, antioxidants and rust inhibitors are blended in the base oil.

  However, since the viscosity of the grease 8 is not sufficient under low temperature conditions such as −40 ° C. to −30 ° C. (in other words, the viscosity is increased), the grease 8 enclosed in the space 10 is removed from the deep groove ball bearing 1. If it is scraped off due to rotation, it is difficult for the grease 8 to be newly supplied to the space 10, resulting in poor lubrication and the occurrence of abnormal noise.

  Therefore, in the deep groove ball bearing 1 of the present embodiment, the volume of the space 10 is increased by increasing the ratio of the radius of curvature R of the raceway surface of the inner raceway groove 3a to the diameter D of the ball 4, and the inner ring raceway groove 3a. In addition, the amount of grease in the vicinity of the contact portion between the ball 4 and the ball 4 is secured, and the inflow property of new grease 8 is improved to ensure lubrication performance. Further, by reducing the ratio of the groove depth H of the inner raceway groove 3a to the diameter D of the ball 4, the contact portion between the inner ring raceway surface 3a and the ball 4, and the vicinity of the contact portion, that is, the grease 8 to the space 10 is provided. Has improved the inflow characteristics.

  Here, like the deep groove ball bearing 1 incorporated in the alternator, the inner ring rotating type deep groove ball bearing 1 in which the outer ring 2 is fixed to a housing (not shown) and the inner ring 3 is rotated is enclosed. The grease 8 interposed between the inner raceway groove 3a and the ball 4 is easily moved to the outer ring 2 side due to a centrifugal force acting on the grease 8, and generally the raceway groove with respect to the diameter D of the ball 4 Since the radius of curvature R of the inner ring 3 is smaller than that of the outer ring 2, it is particularly effective to take the above-described measures on the inner raceway groove 3a of the inner ring 3 which is a rotating ring.

  The ratio of the curvature radius R of the inner raceway groove 3a to the diameter D of the ball 4 is 51.5% to 55%, and the ratio of the groove depth H of the inner ring raceway groove 3a to the diameter D of the ball 4 is 18.5% to 21%.

  FIG. 3 shows the experimental results confirming the noise suppression effect at low temperatures when the ratio of the radius of curvature R of the inner track groove 3a to the diameter D of the balls 4 is changed. The experiment prepared deep groove ball bearings 1 in which the ratio of the radius of curvature R of the inner raceway groove 3a with respect to the diameter D of the balls 4 was changed, and for the alternators in which these deep groove ball bearings 1 were respectively incorporated, The process of rotating for a fixed time at 6000 rpm after being left in the room for a predetermined time was repeated to investigate the occurrence of abnormal noise. As described above, by repeating the rotation and stop of the bearing in a low temperature state, the contact portion between the inland track groove 3a and the ball 4 and the grease 8 in the vicinity of the contact portion are scraped off. Connected.

  As shown in FIG. 3, as a result of the experiment, when the ratio of the radius of curvature R of the inner raceway groove 3a to the diameter D of the ball 4 is 51% or less, the number of repetitions of the above steps until the occurrence of abnormal noise is abrupt. It can be seen that the number of repetitions of the above-described process until the occurrence of abnormal noise suddenly increases when it reaches 51.5% or more, and then tends to increase slightly thereafter. Therefore, in order to prevent the generation of abnormal noise at a low temperature, it is preferable that the ratio of the radius of curvature R of the inner raceway groove 3a to the diameter D of the ball 4 is 51.5% or more. If the ratio of the radius of curvature R of the inner raceway groove 3a with respect to the diameter D of the ball 4 is increased, the contact surface pressure between the inner raceway groove 3a and the ball 4 increases, which may cause damage due to rolling fatigue. The ratio of the radius of curvature R of the inner raceway groove 3a to the diameter D of the ball 4 is preferably 55% or less.

  FIG. 4 shows the experimental results confirming the noise suppression effect at low temperatures when the ratio of the groove depth H of the inner track groove 3a to the diameter D of the ball 4 is changed. In the experiment, a deep groove ball bearing 1 in which the ratio of the groove depth H of the inner track groove 3a to the diameter D of the ball 4 was changed was prepared, and an alternator in which each of these deep groove ball bearings 1 was incorporated was −40 ° C. The process of rotating for a fixed time at 6000 rpm after being left in the room for a predetermined time was repeated to investigate the occurrence of abnormal noise.

  As a result of the experiment, it has been found that when the ratio of the groove depth H of the inner track groove 3a to the diameter D of the ball 4 exceeds 21%, the number of repetitions of the above steps until abnormal noise occurs is reduced. That is, it can be seen that the groove depth H should be 21% or less and shallower in order to prevent the generation of abnormal noise at low temperatures. If the groove depth H is made too shallow, the possibility that the life of the deep groove ball bearing 1 is reduced due to the balls 4 riding on the inner track grooves 3a increases, so the inner track grooves 3a with respect to the diameter D of the balls 4 are increased. It is preferable to set the ratio of the groove depth H to 18.5% or more.

  As described above, generation of abnormal noise is effectively suppressed in use under low temperature conditions, and the contact surface pressure between the inner track groove 3a and the ball 4 is not increased, and the ball 4 can be put on the inner track groove 3a. In order to prevent raising, the ratio of the radius of curvature R of the inner raceway groove 3a to the diameter D of the ball 4 is 51.5% to 55%, and the groove depth H of the inner ring raceway groove 3a to the diameter D of the ball 4 is The ratio is preferably 18.5% to 21%.

  According to the deep groove ball bearing 1 of the present embodiment, the ratio of the radius of curvature R of the inner ring raceway groove 3a to the diameter D of the rolling element 4 is 51.5% to 55%, and the inner ring raceway to the diameter D of the rolling element 4 Since the ratio of the groove depth H of the groove 3a is 18.5% to 21%, the relationship between the curvature radius R and groove depth H of the inner ring raceway groove 3a and the diameter D of the rolling element 4 is optimized. The inflow property of the grease 8 to the vicinity of the contact portion between the inner ring raceway groove 3a and the rolling element 4 is improved. Thereby, the lubrication performance at low temperatures can be improved and the generation of abnormal noise at low temperatures can be effectively suppressed without changing the blending of grease.

  Further, according to the deep groove ball bearing 1 of the present embodiment, the grease 8 having an ether base oil is enclosed, so that the lubricating performance at high temperature is excellent, and in combination with the above effects, High lubrication performance can be secured in a wide temperature range from high temperature to low temperature.

  In addition, this invention is not limited to embodiment mentioned above, A deformation | transformation, improvement, etc. are possible suitably. In addition, the material, shape, dimension, numerical value, form, number, arrangement location, and the like of each component in the above-described embodiment are arbitrary and are not limited as long as the present invention can be achieved.

  For example, in the above-described embodiment, the present invention is applied to the inner ring raceway groove 3a of the inner ring 3 which is a rotating ring in the inner ring rotating type deep groove ball bearing 1, but in the outer ring rotating type deep groove ball bearing, the rotating ring is used. The present invention is applied to the outer ring raceway groove 2 a of the outer ring 2.

It is a longitudinal cross-sectional view of the deep groove ball bearing which is one Embodiment of this invention. It is a principal part enlarged view which shows the relationship between the ball | bowl in FIG. 1, and an inner ring raceway groove | channel. It is a graph which shows the relationship between the curvature radius of an inner ring raceway groove, and the abnormal noise at the time of low temperature. It is a graph which shows the relationship between the groove depth of an inner ring raceway groove | channel, and the abnormal noise at the time of low temperature.

Explanation of symbols

1 Deep groove ball bearing (rolling bearing)
2 Outer ring (fixed ring)
2a Outer ring raceway groove (fixed ring start groove)
3 Inner ring (rotating wheel)
3a Inner ring raceway (rotating ring raceway)
4 ball 8 grease D ball diameter H groove depth of inner ring raceway groove radius of curvature of inner ring raceway groove

Claims (2)

A plurality of balls rotatably disposed between a fixed ring, a rotating ring, and a fixed ring raceway groove and a rotating ring raceway groove provided on circumferential surfaces of the fixed ring and the rotating ring facing each other. A rolling bearing comprising:
The ratio of the radius of curvature of the rotating ring raceway groove to the diameter of the ball is 51.5% to 55%, and the ratio of the groove depth of the rotating ring raceway groove to the diameter of the ball is 18.5% to 21%. Rolling bearings characterized by%.   The rolling bearing according to claim 1, wherein grease having an ether base oil is enclosed.

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