JP2001227552A - Rolling bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rolling bearing excellent in initial acoustic performance and durable longevity performance even in the case that a diameter of a rolling element is extremely small. SOLUTION: This rolling bearing is constituted by furnishing an outer ring 2, an inner ring 3, a plural number of balls 4 arranged free to roll between the outer ring 2 and the inner ring 3, a crown type holder 5 to hold a plural number of the balls 4 between the outer ring 2 and the inner ring 3 and grease 7 arranged in a bearing space 8 formed between the outer ring 2 and the inner ring 3 and in which the balls 4 are provided, furnishing a deep-groove ball bearing 1 an inside diameter of which is 1-4 mm and a diameter of the ball 4 of which is 0.5-1.0 mm so that the grease 7 of 15-35 vol.% of capacity of the bearing space 8 does not make contact with the balls 4, furnishing a lubricant film on track surfaces 2a, 3a of the outer ring 2 and the inner ring 3 and surfaces of the balls 4 and the crown type holder 5 and kinematic viscosity of base oil of the grease 7 and base oil of a lubricant forming the lubricant film is to be both 10-100 mm2/s.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rolling bearing,
In particular, a hard disk drive (hereinafter referred to as HDD), a video tape recorder (hereinafter referred to as VTR),
Digital audio tape recorder (hereinafter referred to as DAT), laser beam printer (hereinafter referred to as LBP)
The present invention relates to a rolling bearing that is suitably used for a rotation supporting portion such as.

[0002]

2. Description of the Related Art Although the computer-related industry is a business with a short history as compared with other industrial fields, the speed of technological innovation is high. In particular, HDDs have a short existence period for one model, and new models have been developed one after another with high precision and compactness by introducing new technology.

Against this background, rolling bearings used in information devices such as HDDs are subject to severer operating conditions, such as a higher operating environment and a higher rotation speed of an outer ring. In addition, on the other hand, not only high performance such as low torque, low noise and long life, but also thinning (difference between outer diameter and inner diameter is less than 4 mm) and narrowing (width 2 mm or less) are required. Has been requested.

In conventional rolling bearings used for HDDs, VTRs, DATs, LBPs and the like, a lubrication method in which grease is filled in the bearing (grease lubrication), or lubricating oil is applied to the bearing raceway surface, etc. The lubrication method of sealing the grease into the bearing is adopted.
It supports high performance such as low noise and long life. For example, in a rolling bearing used for an information device such as an HDD, the grease lubrication is mainly employed.

On the other hand, there is also known a method of achieving high performance such as low torque, low noise, and long life by applying lubricating oil to a bearing raceway surface without using any grease. I have. For example, JP-A-5-149343 discloses that lubricating oil (poly-α-olefin oil, polyol ester oil, polyphenyl ether oil, silicone oil, fluorine oil, etc.) is used for the raceway surfaces of the inner and outer races, the rolling elements and the holding members. It describes that by applying oil to the surface of the container, abnormal noise during cold time can be prevented. Japanese Patent Application Laid-Open No. 64-46011 also describes a rotation support device coated with lubricating oil.

[0006]

In a conventional grease lubricated rolling bearing or a rolling bearing coated with lubricating oil as described above, the inner diameter of the rolling bearing is more than 4 mm and the diameter of the rolling element is a steel ball. Is more than 1.0 mm, and in the case of ceramics such as silicon nitride having a low specific gravity, it is almost always more than 1.2 mm.

However, the lubrication method adopted in the above-mentioned conventional rolling bearing is such that the diameter of the rolling element is 1.0 mm or less for steel balls and 1.2 mm for ceramics.
In the following, it is often difficult to achieve high performance such as low torque, low noise, and long life even when applied to a thin and narrow rolling bearing having an inner diameter of 4 mm or less. In other words, the diameter of the rolling element becomes smaller and the inertial force is reduced, and the rolling element itself slides on the contact surface between the rolling element and the inner / outer ring, causing surface damage, thereby lowering the initial acoustic performance and thus the durability life performance. There was a problem that there is.

Therefore, the present invention solves the above-mentioned problems of the conventional rolling bearing, and provides a rolling bearing having excellent initial acoustic performance and durability life even when the diameter of the rolling element is extremely small. That is the task.

[0009]

In order to solve the above problems, the present invention has the following arrangement. That is, the rolling bearing according to the present invention includes an outer ring, an inner ring, a plurality of rolling elements rotatably disposed between the outer ring and the inner ring, and the plurality of rolling elements between the outer ring and the inner ring. A retainer for holding a moving body, a lubricating oil retainer formed between the outer ring and the inner ring and disposed in a bearing space in which the rolling element is provided,
And a rolling bearing having an inner diameter of 1 to 4 mm and a diameter of the rolling element of 0.5 to 1.0 mm,
The lubricating oil holding body of 15 to 35 vol% of the volume of the bearing space is provided so as not to contact the rolling element, and at least the raceway surfaces of the outer ring and the inner ring and the surface of the rolling element are lubricated. And a kinematic viscosity at 40 ° C. of the base oil held by the lubricating oil holder and the base oil of the lubricant forming the lubricant film is 10 to 1
It is characterized by being 00 mm ² / s.

With such a configuration, the rolling element rotates smoothly even under the conditions of high temperature and high speed rotation, so that the initial acoustic performance is excellent. In particular, since the lubricating oil holder is provided so as not to contact the rolling element, the lubricating oil holder hardly comes into contact with the rolling element even when the rolling bearing rotates, The base oil held by the lubricating oil holder is gradually released, and the lubricating action can be maintained for a long period of time. Therefore, even in a rolling bearing having a very small diameter of the rolling element, the problem of causing surface damage due to the sliding of the rolling element itself does not easily occur, so that the durability life performance is excellent.

(Regarding Lubricant Film) The rolling bearing of the present invention comprises a plurality of steel rolling elements having a diameter of 0.5 to 1.0 mm or a diameter of 0.6 mm through a retainer between the inner and outer rings. ~
A 1.2 mm ceramic rolling element is held. It is necessary to provide a lubricant film having a thickness of 0.1 to 10 μm on at least the raceway surfaces of the inner and outer races and the surfaces of the rolling elements and the cage. If the thickness of the lubricant film is less than 0.1 μm, the thickness tends to be uneven, and there is a possibility that a portion where no lubricant is present is generated and the durability life performance is reduced. Conversely, the film thickness is 10 μm
In the case of exceeding, the lubricant film becomes a resistance, causing slippage of the rolling elements and possibly causing surface damage. In order to achieve sufficient durability life performance, the film thickness should be 1 to 10 μm.
m is more preferred.

The method of forming the lubricant film is not particularly limited, but it is necessary to adopt a method capable of controlling the film thickness. For example, there is a method in which the assembled rolling bearing is immersed in a lubricant, pulled up, and then centrifugally deoiled. According to such a method, it is possible to form a film while adjusting the film thickness by the rotation speed and the rotation time in centrifugal deoiling. The viscosity of the base oil of the lubricant forming the lubricant film must have a kinematic viscosity at 40 ° C. of 10 to 100 mm ² / s. 1
If it is less than 0 mm ² / s, there is a problem in durability of the lubricant film at a high temperature, and if it is more than 100 mm ² / s, the rolling element tends to slip due to viscous resistance.

The lubricant is a composition comprising a base oil and various additives described below, and is suitable for use under high temperature and high speed rotation which is the object of the present invention, in addition to lubricity. A lubricant film is obtained. The base oil preferably contains an ester oil in consideration of lubricity and heat resistance. The type of the ester oil is not particularly limited, but is a diester oil obtained from a reaction between a dibasic acid and a branched alcohol, an aromatic ester oil obtained from a reaction between an aromatic tribasic acid and a branched alcohol, and a polyvalent oil. Hindered ester oils and the like obtained from the reaction between alcohol and monobasic acid are suitably used.

Further, a refined mineral oil, a synthetic hydrocarbon oil, and an ether oil can be blended as the base oil component in the ester oil. Refined mineral oils include naphthenic and paraffinic mineral oils. Examples of the synthetic hydrocarbon oil include a poly-α-olefin oil, a co-oligomer synthetic oil of an α-olefin and ethylene, and the like. Further, examples of the ether oil include phenyl ether oils (diphenyl ether, triphenyl ether, and tetraphenyl ether substituted with one or two alkyl groups having 12 to 20 carbon atoms). In particular, the phenyl ether oil is preferable in consideration of heat resistance and durability at high speed rotation. Refined mineral oil, synthetic hydrocarbon oil,
The mixing ratio of the ether oil is preferably 80% by weight or less based on the amount of the ester oil.

The durability of the lubricant film can be improved by adding a rust inhibitor, an oil agent, an antioxidant and the like to the base oil. As the rust inhibitor, an organic metal sulfonic acid salt or ester is preferable. As the oil agent, higher fatty acids such as oleic acid and stearic acid, higher alcohols such as lauryl alcohol and oleyl alcohol, amines such as stearylamine and cetylamine, and phosphate esters such as tricresyl phosphate are preferable. These can be used alone or in combination of two or more.

Further, as the antioxidant, a mixture of a nitrogen-containing compound antioxidant and a phenolic antioxidant is preferable. Examples of the nitrogen-containing compound-based antioxidant include phenyl-α-naphthylamine, diphenylamine, phenylenediamine, oleylamideamine, phenothiazine and the like. Phenolic antioxidants include p
Hindered phenols such as -tert-butylphenyl salicylate and 2,6-di-tert-butyl-4-phenylphenol. It should be noted that it is difficult to improve the acoustic characteristics with only one of the nitrogen-containing compound antioxidant and the phenolic antioxidant.

The composition may contain additives such as an extreme pressure agent, a viscosity index improver, and an antiwear agent, in addition to the above components. Any of these can be conventionally known ones. (About the lubricating oil holder) The rolling bearing of the present invention has a structure in which the lubricating oil holder is provided in a bearing space formed between the outer ring and the inner ring and in which the rolling element is provided.

The lubricating oil holder includes grease, oil-impregnated plastic, and the like, and holds a base oil having a kinematic viscosity at 40 ° C. of 10 to 100 mm ² / s. Grease is a gel or semi-solid material composed of a base oil and an additive. It can be used as a base material for metallic soaps such as barium, lithium, and aluminum, and non-soaps such as diurea and lipophilic bentonite. It is obtained by adding to a base oil, heating and dissolving, and then cooling. The oleoresin is a solid resin containing a base oil.

The base oil gradually oozes out of the lubricating oil holder with the rotation of the rolling bearing, so that poor lubrication at the beginning of rotation is improved as compared with the case of the lubricant film alone. At the same time, the synergistic effect with the lubricating action of the lubricant film can improve the lubricating property itself and maintain the lubricating action for a long time. In particular, if the base oil held by the lubricating oil holder is compatible with the base oil used in the lubricant, the base oil of the lubricating oil holder and the base oil of the lubricant separate. And a more excellent lubrication action can be obtained. Also, it is preferable that the additives be the same.

The content of the base oil in the lubricating oil holder is not particularly limited, but is preferably at least 10% by weight based on the total weight of the lubricating oil holder. If the content is less than 10% by weight, the amount of the base oil is not sufficient for lubrication of the rolling bearing, and the contribution to the improvement of the acoustic durability is insufficient. In order to make the amount of the base oil more sufficient, it is more preferably at least 30% by weight. The upper limit of the content of the base oil is not particularly limited, but when the content increases, the lubricating oil holder tends to soften, so that the lubricating oil holder may not have the shape retention described below. . Therefore, in view of this shape retention,
The upper limit is set as appropriate.

The lubricating oil holding member needs to stay at a predetermined position in the bearing space of the rolling bearing as described later so as not to contact the rolling element. For this purpose, the lubricating oil holding body needs to have a certain degree of shape retention. When the lubricating oil holder is grease, the consistency specified by JIS K2220 is 200
~ 330 is preferable. If it exceeds 330, the grease is too soft, and the grease flows during the rotation of the rolling bearing, and a part of the grease restricts the rotation of the rolling element with respect to the raceway surface to cause slip, and the surface is damaged. May cause If it is less than 200, the grease is too hard, and the supply of the base oil to the rolling elements becomes insufficient.

The viscosity of the base oil held by the lubricating oil holder
Has a kinematic viscosity at 40 ° C. of 10 to 100 mm^Two/ S
Need to be. 10mm^Two/ S at high temperatures
There is a problem in durability, 100mm^Two/ S excess
The rolling resistance tends to slip due to the resistance. Rolling element
10 to 80 mm
^Two/ S is more preferable.

[0023] The amount of the lubricating oil holder provided in the rolling bearing must be 15 to 35 vol% of the volume of the bearing space. If the amount of the lubricating oil holder is less than 15 vol% of the volume of the bearing space, the amount of the base oil is not sufficient for lubrication of the rolling bearing, and a sufficient lubricating action cannot be obtained. On the other hand, when the content is 35 vol% or more, the lubricating oil holding body hinders the rotational movement of the rolling element, and the possibility of the sliding of the rolling element increases. Here, the volume of the bearing space is a value obtained by subtracting the volumes of the rolling elements and the retainer from the volume of the ring-shaped space formed between the outer ring and the inner ring and having the rolling elements provided therein. When a seal member is provided,
The value is obtained by subtracting the volumes of the rolling elements and the retainer from the volume of the space formed by the outer ring, the inner ring, and the seal member.

The lubricating oil holding member must be provided so as not to come into contact with the rolling element in the bearing space of the rolling bearing. As a result, as described above, even when the rolling bearing rotates, it hardly comes into contact with the rolling elements, and gradually releases the base oil held by the lubricating oil holding body, thereby providing a long-term lubricating effect. Can be maintained. Therefore, even in a rolling bearing having a very small diameter of the rolling element, the problem of causing surface damage due to the sliding of the rolling element itself does not easily occur, so that the durability life performance is excellent.

When the lubricating oil holding member is provided in contact with the rolling element, the supply of the base oil to the lubricated portion is excessive, and the possibility of the sliding of the rolling element increases. In addition, the lubricating effect is not maintained for a long time. As a method of providing the lubricating oil holder so as not to contact the rolling element, a position facing a portion of the cage that is not in contact with the rolling element (may or may not be in contact with the cage). A method including the above-mentioned lubricating oil holder is exemplified.
For example, in the case of a crown type cage, a single type cage, and a cage type cage, it is preferable to install them on the back side of the cage or at a portion between pockets. In the case of a waveform holder, the outer surface side of the pocket is preferable. In the present invention, the back surface refers to a surface of the annular cage that is not provided with one (a surface opposite to the surface that holds the rolling elements) or an axial end that is not open. Means side.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a rolling bearing according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a partial sectional view showing one embodiment of the rolling bearing of the present invention.
Thin and narrow single row deep groove ball bearing 1 (No .: 681)
X, inner diameter 1.5 mm, outer diameter 2.15 mm, width 2 mm, rolling element diameter 0.4 mm, manufactured by Nippon Seiko Co., Ltd.)
An inner ring 3, a plurality of balls 4 rotatably disposed between the outer ring 2 and the inner ring 3, a crown retainer 5 made of a polyamide resin for holding the plurality of balls 4, And a non-contact type shield (Z type) 6. The shield 6 is attached to the seal groove 2b of the outer ring 2 in a non-contact state with the inner ring 3. The plurality of balls 4 are rotatably held by a crown-shaped retainer 5 in a state where they are equally spaced from each other over the circumferential direction of the deep groove ball bearing 1. A grease 7 is filled in a later-described position of a bearing space 8 surrounded by the outer ring 2, the inner ring 3, and the shield 6, and is sealed inside the deep groove ball bearing 1 by the shield 6.

The position where the grease 7 is installed in the bearing space 8 is on the back side of the crown-shaped retainer 5 and is installed so as not to contact the ball 4. In addition, the back surface means the side of the axial end that is not open. The filling amount of the grease 7 is determined by the volume of the bearing space 8 (from the volume of the ring-shaped space formed by the outer ring 2, the inner ring 3, and the shield 6 and having the ball 4 provided therein, the ball 4 and the crown-shaped cage 5. 35 vol% of the value obtained by subtracting the volume of the above). Grease 7 was prepared by adding lithium 12-hydroxystearate as a thickener to a base oil having a kinematic viscosity at 40 ° C. of 30 mm ² / s to a consistency of 250.

The raceway surfaces 2a, 3a of the inner and outer races 2, 3
A lubricant film (not shown) having a film thickness of 10 μm is provided on the surface of the ball 4 and the crown-shaped cage 5. The lubricant forming this lubricant film has a kinematic viscosity at 40 ° C. of 10 to 1
A mixture of ester oil of 00 mm ² / s as base oil, 4.45% by weight of calcium sulfonate as rust inhibitor, 0.03% by weight of phenylenediamine and 0.02% by weight of hindered phenol as antioxidants ,
Compositions each containing 0.5% by weight of tricresyl phosphate as an oiliness improver were used.

The method for forming the lubricant film and the method for adjusting the film thickness were as follows. The deep groove ball bearing 1 was immersed in the lubricant, pulled up, and then drained by blowing air to roughly remove excess lubricant. Further, the lubricant remaining in the deep groove ball bearing 1 was removed by a centrifugal separator. The adjustment of the film thickness was performed by adjusting the magnitude of the centrifugal force generated by the centrifuge and the rotation time.

The deep groove ball bearing 1 of FIG.
Despite being a thin and narrow rolling bearing having a very small diameter of a rolling element, it has excellent initial acoustic performance and a long life even under high-temperature, high-speed rotation conditions. In addition, grease 7 is placed on the back side of
As shown in FIG. 2, the grease 7 contacts the ball 4 on the front side (the side of the axial end that is open) of the crown-shaped retainer 5 as shown in FIG. Unlike the case where the grease 7 is installed, the grease 7 remains at the initial position where the grease 7 is installed even when the deep groove ball bearing 1 rotates, and gradually releases the base oil held by the grease 7 for a long time. Lubrication can be maintained. Therefore, although the diameter of the ball 4 is extremely small, the problem that the ball 4 slides to cause surface damage to the raceway surfaces 2a, 3a and the surface of the ball 4 hardly occurs, so that the durability life performance is excellent.

(Examples and Comparative Examples) An acoustic test was performed using a single-row deep groove ball bearing having substantially the same configuration as described above. The six types of single row deep groove ball bearings used and the test conditions are shown in the following (1) to (5). (1) Types of bearings a) Thin, narrow, single-row, deep-groove ball bearings: non-contact metal shield (Z type), identification numbers 681X, 681XA, 681X
B, inner diameter 1.5 mm x outer diameter 2.15 mm x width 2 mm, rolling element diameter 0.4, 0.5, 0.8 mm a) Single row deep groove ball bearing: non-contact rubber seal (V type), nominal number 694 , Inner diameter 4mm x outer diameter 10mm x width 2mm,
Rolling element diameter 1.0 mm c) Single row deep groove ball bearing: non-contact rubber seal (V type), nominal number 695, 695 A, inner diameter 5 mm x outer diameter 13 mm x
4 mm width, rolling element diameter 2.0 mm and 1.6 mm (2) Method of forming lubricant film on bearing and method of adjusting film thickness Lubricant similar to lubricant used in deep groove ball bearing 1 of the above embodiment (However, the kinematic viscosity at 40 ° C. is 5 to 5.
The single-row deep groove ball bearing described in (1) above was immersed in a base oil of 200 mm ² / s), and a lubricant film was formed in the same manner as in the embodiment. (3) Grease To a base oil having a kinematic viscosity at 40 ° C. of 5 to 165 mm ² / s, lithium 12-hydroxystearate is added as a thickening agent at various mixing ratios, and several kinds of grease having a consistency of 250 are added. Grease was produced. (4) Installation position of cage and grease As the cage, a polyamide crown-shaped cage as shown in FIGS. 1 and 2 was used. The grease is installed at the positions as shown in FIGS. 1 and 2, that is, at the rear side (FIG. 1) and the front side (FIG. 2) of the crown cage, the grease contacts the rolling elements as much as possible. It was set up not to be. (5) Conditions of acoustic test Bearing rotation speed: 7200 rpm (inner ring rotation) Axial load: 0.4N (681X, 681XA, 6
81XB) 10N (694) 20N (695, 695A) Ambient temperature: 80 ° C Judgment criteria: The acoustic measurement of the bearing is performed using an anderon meter, and the bearing anderon value (initial anderon value) immediately after the grease is sealed and 5000 A case where the difference (magnitude of the degree of rise) from the bearing anderon value after time rotation was 0 to 1.0 was judged as acceptable, and 1.1 or more was judged as unacceptable. Note that this criterion was set to be much harsher than that of the completed bearing.

An acoustic test was performed on various single-row deep groove ball bearings having different conditions, and the number of tests was n = 1.
The correlation between each condition and acoustic characteristics was examined based on the ratio of the number of rejects when the number was set to 000. The result is shown in FIG.
Hereinafter, a) to e) will be described with reference to FIGS. The rejection rate in each figure and table is defined as the rejection rate of the largest rejection rate among all tested bearings.
The relative values are shown. a) Correlation between diameter of rolling element and acoustic characteristics First, an acoustic test of the bearing was performed by changing the diameter of the ball variously.
The results are shown in FIG.

In the test shown in FIG. 3, the kinematic viscosities at 40 ° C. of the lubricant base oil and the grease base oil forming the lubricant film were both 30 mm ² / s, and the thickness of the lubricant film was 20 μm. The amount of filled grease is 50% of the bearing space volume, and the consistency of grease is 250. As can be seen from FIG. 3, the bearing has a property that the smaller the diameter of the rolling element, the lower the acoustic characteristics. b) Correlation between kinematic viscosity (40 ° C.) of grease base oil and acoustic characteristics is shown in FIG. In the test of FIG. 4, the bearing used was a reference number 681X, and the kinematic viscosity at 40 ° C. of the base oil of the lubricant forming the lubricant film was the same as the kinematic viscosity of the base oil of the grease. Has a thickness of 10 μm, the amount of filled grease is 35% of the bearing space volume, the consistency of the grease is 250, and the installation position of the grease is on the front side of the cage.

As can be seen from FIG. 4, when the kinematic viscosity of the grease base oil was 10 to 100 mm ² / s, the rejection rate was low. When the rate was less than 10 mm ² / s, the rejection rate sharply increased, and when it exceeded 100 mm ² / s, the rejection rate gradually increased. From these results, it was confirmed that the correlation between the kinematic viscosity (40 ° C.) of the base oil of the lubricant forming the lubricant film and the acoustic characteristics had the same relationship as described above. c) Correlation between lubricant film thickness and acoustic characteristics The lubricant film thickness was controlled by variously changing the centrifugal deoiling conditions. FIG. 5 shows the results. In the test shown in FIG. 5, the bearing used was a nominal number 681X, and the base oil of the lubricant forming the lubricant film and the base oil of the grease at 40 ° C.
Kinematic viscosity is 30 mm ² / s, grease filling amount is 35% of bearing space volume, grease consistency is 25
0, the grease installation position is on the back of the cage.

As can be seen from FIG. 5, the rejection rate was low when the thickness of the lubricant film was 0.1 to 10 μm. When the lubricant film is not provided, the thickness is 0.1 μm
The rejection rate is extremely high compared to the case where
If it exceeds 0 μm, the rejection rate gradually increases. d) Correlation between grease filling amount and acoustic characteristics Fig. 6 shows the results. In the test shown in FIG. 6, the bearings used were nominal number 681X, the kinematic viscosities of the lubricant forming the lubricant film and the grease base oil at 40 ° C. were both 30 mm ² / s, The film thickness is 10 μm, the consistency of the grease is 250, and the installation position of the grease is on the back side of the cage.

As can be seen from FIG. 6, the rejection rate was low when the amount of grease charged was 15 to 35 vol%. And grease filling amount is less than 15 vol% and 35 vol.
If it exceeded 1%, the rejection rate gradually increased. e) Correlation between grease installation position and acoustic characteristics Table 1 shows the results. In the tests shown in Table 1, the bearings used were nominal number 681XA, the kinematic viscosities of the base oil of the lubricant forming the lubricant film and the base oil of the grease at 40 ° C. were both 30 mm ² / s, The film thickness is 10 μm,
The amount of filled grease is 35% of the bearing space volume, and the consistency of grease is 250.

[0037]

[Table 1]

As can be seen from Table 1, when the grease is installed at the rear side of the cage, the rejection rate is lower than that at the front side. Note that the present embodiment is an example of the present invention, and the present invention is not limited to the present embodiment. For example, in the present embodiment, a single row deep groove ball bearing has been described as an example of the rolling bearing. However, the rolling bearing of the present invention can be applied to various other types of rolling bearings. For example, tapered roller bearings, cylindrical roller bearings, spherical roller bearings, angular contact ball bearings, and the like.

[0039]

As described above, the rolling bearing of the present invention, which is thin and narrow and has a very small diameter of the rolling element, can smoothly rotate even under the conditions of high temperature and high speed rotation. Is excellent, and further, the durability life performance is excellent.

[Brief description of the drawings]

FIG. 1 is a partial sectional view showing one embodiment of a rolling bearing of the present invention.

FIG. 2 is a partial sectional view showing a structure of a rolling bearing of a comparative example.

FIG. 3 is a graph showing a relationship between a diameter of a rolling element and a rejection rate of an acoustic test.

FIG. 4 is a graph showing the relationship between the kinematic viscosity of a grease base oil and the rejection rate of an acoustic test.

FIG. 5 is a graph showing the relationship between the thickness of a lubricant film and the rejection rate of an acoustic test.

FIG. 6 is a graph showing the relationship between the amount of filled grease and the rejection rate of an acoustic test.

[Explanation of symbols]

 Reference Signs List 1 deep groove ball bearing 2 outer ring 2a raceway surface 3 inner ring 3a raceway surface 4 ball 5 crown retainer 6 shield 7 grease 8 bearing space

Claims (1)

[Claims] 1. An outer ring, an inner ring, a plurality of rolling elements rotatably disposed between the outer ring and the inner ring, and the plurality of rolling elements held between the outer ring and the inner ring. A retainer, and a lubricating oil retainer formed between the outer ring and the inner ring and disposed in a bearing space in which the rolling element is provided, and has an inner diameter of 1 to 4 mm, In a rolling bearing having a rolling element having a diameter of 0.5 to 1.0 mm, the lubricating oil holding body having a volume of 15 to 35% by volume of the bearing space is provided so as not to come into contact with the rolling element. A lubricant film is provided on the raceway surfaces of the outer ring and the inner ring and the surface of the rolling element, and a base oil of the base oil held by the lubricating oil holding body and a base oil of the lubricant forming the lubricant film are provided. Kinematic viscosity at 40 ° C. is 10
A rolling bearing having a diameter of 100 mm ² / s.