JP2000120708A - Rolling bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an excellent bearing sound characteristic under low temperature and high temperature and to reduce the sound of a holder at starting under low temperature by providing an axial cylindrical surface on each pocket inner surface of the holder, and sealing a grease containing a thickener consisting of a specified material and an ester oil having a specified dynamick viscosity. SOLUTION: A holder 7 has an axial cylindrical surface 18 having the peripheral side opening edge of a holder 7 as the central axis on at least a part of the inner surface of each pocket 9. A grease is sealed which contains a thickener selected from a lithium salt of fatty acid containing no hydroxyl group, a lithium salt of fatty acid containing hydroxyl group and a mixture thereof and a base oil having a kinematic viscosity at about 40 deg.C of about 30-150 mm2/s and containing an ester oil as an essential component. The grease can easily penetrate into the clearance between the inner surface of the pocket 9 and a rolling body by use of the holder 7 having the axial cylindrical surface 18, and the grease excellent in durable performance at low temperature and high temperature is used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a rolling bearing,
In particular, the present invention relates to a rolling bearing that improves cage sound at low temperatures and bearing acoustic performance at high temperatures, and is suitable for extending the life of acoustic characteristics at high to low rotation speeds.

[0002]

2. Description of the Related Art In recent years, air conditioners (air conditioners) have become more sophisticated and multifunctional. For example, after a room temperature has been reduced in a short time by rapid cooling by high-speed operation, a constant temperature has been reduced by low-speed operation. It has been done to maintain. At the time of low-speed operation, low-noise operation that suppresses air blowing noise, motor rotation noise, and the like is required. However, during low-speed operation, the cooling efficiency inside the device decreases, and the temperature of the bearing incorporated in the motor may rise to around 100 to 120 ° C. As a result, the bearing-enclosed grease tends to deteriorate. And if the deterioration is promoted,
It could cause noise. Also, in the outdoor unit used for the air conditioner, it was considered that the initial sound of the bearing (cage sound) at the time of startup at a low temperature in winter or the like may become a problem.

Conventionally, as a grease for a bearing of an air conditioner, lithium soap is used as a thickener, and dioctyl sebacate (DOS) or pentaerythritol (PE) is used as a base oil.
T) and the like, and the viscosity is 80 mm ² /
Grease of less than s (40 ° C.) is generally used. However, this grease composition has excellent acoustic characteristics at the beginning of operation and at low temperatures, but has the problem that the acoustic characteristics at high temperatures are easily deteriorated early.

In order to solve the above problems,
The applicant also discloses in JP-A-8-209176 that a hydroxyl group
Lithium salt of fatty acid having fatty acid and fatty acid not containing hydroxyl group
Soap containing a specific proportion of lithium salt
And the viscosity is 80-300mm ^Two/ s ester oil
A base oil to improve the acoustic characteristics at high temperatures.
Discloses leases. In addition, the present applicant has disclosed in
38434 and Japanese Patent Application No. 9-335304
In order to improve the generation of bearing cage noise,
Disclose or propose a cage with a special shape
I have. In addition, the present applicant has disclosed in Japanese Patent Application No. 10-40222.
At least in the radial direction of the pocket
Cage with chamfered part of the opening edge
A rolling bearing enclosing a grease composition has been proposed.

[0005]

However, with the demand for higher performance of the air conditioner, the rolling bearings to be incorporated are required to be further improved with respect to high-speed rotation, miniaturization, low noise, and the like. I have. The present invention has been made in view of such a situation, and provides a rolling bearing which has excellent bearing acoustic characteristics at low and high temperatures and reduces cage noise at the time of starting at low temperatures. With the goal.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a rolling element having at least a part of the inner surface of each pocket of a retainer including a peripheral opening edge of the retainer. A rolling bearing comprising an axial cylindrical surface having a rolling center axis as its center axis, and a plurality of rolling elements rotatably held between an inner ring and an outer ring through the retainer, and And a thickener selected from a lithium salt of a fatty acid containing no, a lithium salt of a fatty acid containing a hydroxyl group and a mixture thereof, and a kinematic viscosity at 40 ° C. of 30 to 150 mm ² / s.
And a grease composition containing a base oil containing an ester oil as an essential component. According to the rolling bearing of the present invention, by using the cage provided with the axial cylindrical surface, grease easily enters the gap between the inner surface of the cage pocket and the rolling element, and there is no shortage of grease supply at the contact surface, In addition, by using grease having excellent durability at low and high temperatures, it is possible to extend the acoustic life and reduce cage noise at low temperatures.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a rolling bearing according to the present invention will be described in detail. FIG. 1 is a sectional view showing one embodiment of the rolling bearing of the present invention. As shown in the figure, the rolling bearing is provided with a plurality of rolling elements, balls 5, 5, which can be rolled via a retainer 7 between an inner ring 2 having an inner raceway 1 and an outer race 4 having an outer raceway 3. And a space formed by the inner ring 2, the outer ring 4 and the balls 5, 5 is filled with grease (not shown), and the grease is sealed with the sealing plates 6, 6. The rolling bearing of the present invention is characterized in that an axial cylindrical surface is formed on the inner surface of the pocket of the cage 7. Hereinafter, the axial cylindrical surface will be described.

Although the type of the cage 7 is not particularly limited, a description will be given here by taking the crown type cage shown in FIG. 2 as an example. The crown-shaped retainer 7 is provided at an annular main portion 8 and at a plurality of circumferential positions of the main portion 8, and balls 5 and 5 are provided inside the main portion 8.
And a pocket 9.9 that holds the rolling members 5 one by one. Each pocket 9.9 also has a pair of elastic pieces 10, 10 spaced apart from each other, thereby holding the balls 5, 5. As shown in FIG. 3, a spherical concave surface 17 (first spherical concave surface) is provided on the inner surface of each pocket 9 at the center in the circumferential direction. This spherical concave surface 17 is formed in the pocket 9 similarly to the conventional crown type cage.
Has a radius of curvature that is slightly larger than the radius of curvature of the rolling surface of the ball 5 held at the center. A pair of axial cylindrical surfaces 18, 18, which are characteristic parts of the present invention, are provided on both circumferential sides of the spherical concave surface 17.
It is formed in a state where one end of 18 is continuous from both ends in the circumferential direction of the spherical concave surface 17.

The two axial cylindrical surfaces 18, 18 are:
The rolling center axis α of the ball 5 held in the pocket 9 is set as the center axis. That is, with the relative rotation between the inner ring 2 and the outer ring 4 (FIG. 1), the ball 5 held in the pocket 9 rolls around a rolling central axis α parallel to the central axis of the main part 7. Therefore, the axial cylindrical surface 1 provided one pair for each pocket 9
8, 18 are located on a single cylindrical surface centered on the rolling center axis. Further, 1 is provided at both ends of the pocket 9.
Of the pair of elastic pieces 10, 10, the inner peripheral surface constituting the pocket 9 is concentric with the spherical concave surface 17, or a point different from the center point of the spherical concave surface 17 on the rolling center axis α. The second spherical concave surfaces 19, 19 at the center are provided. The two spherical concave surfaces 19, 19 are formed by a pair of axial cylindrical surfaces 18, 18, in which the running portion of the ball 5 held in the pocket 9 is formed.
A pair of axial cylindrical surfaces 1 so as not to come off
The length and shape are regulated in relation to the lengths of 8, 18. For this purpose, for example, the spherical concave surface 17 and the second spherical concave surface 1
9 and 19 have a radius of curvature slightly larger than the radius of curvature of the rolling surface of the ball 5 and the center thereof is positioned on the rolling center axis α.

In the case of the crown type retainer 7 configured as described above, it becomes possible to take in a necessary amount of grease into the gap between the inner surface of the pocket 9 and the rolling surface of the ball 5. The reason will be described below. When the inner ring 2 and the outer ring 4 constituting the ball bearing rotate relative to each other, the ball 5 rolls around the rolling center axis α. The running portion of the ball 5, that is, the portion where the rolling surface comes into contact with the outer raceway 3 and the inner raceway 1 (FIG. 1) along with the rolling passes through the center point of the ball 5 and is orthogonal to the rolling center axis α. Exist on a plane. Therefore, in the portions corresponding to the axial cylindrical surfaces 18, 18, the rolling surface of the ball 5 held in the pocket 9 and the axial cylindrical surfaces 18, 18
The distance from the traveling portion 18 is small at a portion corresponding to the traveling portion, and increases as the distance from the traveling portion increases. Pocket 9
The same applies to the distance between the edge and the above-mentioned rolling surface at the opening edge. Therefore, among the lubricant adhered to the rolling surface of the ball 5, most of the lubricant adhered to the running portion is scraped off at the opening edge of the pocket 9. Accordingly, it is possible to prevent an excessive lubricant from being present between the rolling surface of the ball 5 and the outer raceway 3 and the inner raceway 1, and to reduce the rotational torque (absolute value and fluctuation range) of the radial ball bearing incorporating the cage. ) Can be reduced.

On the other hand, each axial cylindrical surface 18, 1
In the portion corresponding to 8, the ball 5 held in the pocket 9
The distance between this rolling surface and each of the axial cylindrical surfaces 18 increases as the distance from the running portion increases. For this reason, of the rolling surface of the ball 5, most of the lubricant adhering to the portion deviating from the running portion is in the pocket 9.
Is taken into the pocket 9 without being scraped off at the opening edge. The lubricant taken into the pocket 9 in this manner improves the lubricity between the rolling surface of the ball 5 and the inner surface of the pocket 9 to prevent the occurrence of vibration called cage sound,
In addition, it contributes to improving the durability of the bearing incorporating the cage.

The spherical concave surface 17 and the second spherical concave surface 1
9 and 19 may be concentric with each other, that is, located on a single spherical surface, but effectively prevent the displacement of the retainer in the axial direction and effectively take the lubricant into the pocket 9. Therefore, more preferably, the centers are different from each other. This point will be described with reference to FIG. As shown in FIGS. 3 and 4, a pair of axial cylindrical surfaces 18, 18 are provided on both sides of the pocket 9 in the circumferential direction (left and right directions in FIGS. 3 and 4). Reference numeral 17 denotes one end (the lower end in FIGS. 3 and 4) of the rolling center axis α of the ball 5, and the second spherical concave surfaces 19 and 19 similarly end the other end (see FIGS. 3 and 4).
(Upper end side) portion of each. A point O _{5 in} FIG. 4A is a center point of the ball 5 on the assumption that the ball 5 exists at a neutral position in the pocket 9. Under such conditions, the center point O _{17 of the} curvature of the spherical concave surface 17 is located at a position closer to the other end side than the center O ₅ of the ball 5 on the rolling center axis α. On the other hand, the center point O _{19 of the} curvature of the second spherical concave surfaces 19, ₁₉ is located at a position closer to one end side than the center O ₅ of the ball 5 on the rolling center axis α. Therefore, the degree to which the radius of curvature R ₁₇ , R _{19 of} each spherical concave surface ₁₇ , ₁₉ is larger than the radius of curvature R ₅ of the rolling surface of the ball 5 depends on each of the center points O ₅ , O ₁₇ ,
The case where O _{19 is made} to coincide is markedly higher than that in (B).

As shown in FIG. 4A, each spherical concave surface 1
By shifting the center points O ₁₇ and O ₁₉ of the curvatures 7 and ₁₉ , the minimum values L ₁₇ and L ₁₇ of the distances between the spherical concave surfaces 17 and 19 and the axial cylindrical surfaces 18 and 18 and the rolling surface of the ball 5 are determined.
L ₁₈ and L ₁₉ can be substantially matched. Then, as a result of making the minimum values L ₁₇ , L ₁₈ , L ₁₉ of these distances substantially equal, displacement of the retainer in the axial direction is prevented,
The lubricant can be optimally taken into the pocket 9. This point will be described with reference to FIG. 4B in addition to FIG. As shown in FIG. 4B, the center of curvature of the spherical concave surface 17 and the second spherical concave surfaces 19, 1
In the case of the structure in which the centers of curvature of the spherical surfaces 9 coincide with each other, when the minimum value L ₁₈ ′ of the distance between the pair of axial cylindrical surfaces 18, 18 and the rolling surface of the ball 5 is set to an appropriate value, each spherical concave surface 17 , 19 and the minimum distance L ₁₇ ′, L ₁₉ ′ between the ball 5 and the rolling surface of the ball 5 become excessively large, and the amount of movement of the retainer with respect to the ball 5 in the axial direction becomes excessively large. As a result, the cage is likely to vibrate during operation of the bearing. Conversely, if the minimum values L ₁₇ ′ and L ₁₉ ′ of the distance between the spherical concave surfaces 17 and 19 and the rolling surface of the ball 5 are set to appropriate values, the rolling of the pair of axial cylindrical surfaces 18 and 18 and the ball 5 The minimum value L ₁₈ ′ of the distance to the surface becomes too small, and the lubricant adhering to the running portion of the rolling surface of the ball 5 is removed from the axial cylindrical surface 1.
It becomes easy to be scraped more than necessary at the opening edge of 8,18,
The effect of cage sound reduction is impaired. In contrast, FIG.
As shown in (A), if each center point O ₁₇ , O ₁₉ is shifted, each spherical concave surface 17, 19, axial cylindrical surface 18, 18, and ball 5
The minimum values L ₁₇ , L ₁₈ , and L ₁₉ of the distances from the rolling surface are substantially matched to prevent displacement of the retainer in the axial direction, and to optimally take the lubricant into the pocket 9. Can be done.

Next, FIG. 5 shows a second example of a crown type cage. As is clear from the description of the first example described above, the axial cylindrical surfaces 18 and 18 formed on the inner surface of the pocket 9 are formed of the lubricant adhered to the running portion among the lubricant adhered to the rolling surface of the ball 5. Is sufficiently scraped off so as not to scrape off much of the lubricant adhering to the part deviating from the running part. Therefore, the ball 5 held in the pocket 9
In the case of a cage incorporated in a bearing in which the rolling direction (relative rotation direction of the outer ring and the inner ring) is constant, the axial cylindrical surfaces 18, 18 are not necessarily formed on a part of the inner surface of the pocket 9, but on the inner periphery of the cage. It is not necessary to form the pocket 9 over the entire width from the surface to the outer peripheral surface.

In the structure of the second example shown in FIG. 5, in consideration of such a point, an axial cylindrical surface 18a is formed only on one half in the width direction of the pocket 9. That is, in the case of the present example, an axial cylindrical surface 18a is formed on a part in the width direction of the pocket 9 on one side in the circumferential direction of the main part 7, more specifically on the outer half part in the diameter direction of the main part 7. ing. In the case of this example, the ball 5 (FIG. 4) held in the pocket 9 rotates in the direction indicated by the arrow in FIG. Therefore, of the lubricant adhering to the rolling surface of the ball 5, the lubricant adhering to the running portion can be sufficiently scraped, and the lubricant adhering to the portion deviating from the running portion can be prevented from being scraped much. . Therefore, although not shown, the axial cylindrical surface formed on the other side in the circumferential direction of the main portion 7 is preferably formed on the inner half portion of the main portion 7 in the diameter direction. However, if the lubrication conditions and the like are not very strict, axial cylindrical surfaces may be provided on both sides in the circumferential direction of the main portion 7 on the same side in the diametrical direction of the main portion 7. Each spherical concave surface 17, 19 and axial cylindrical surface 1
8a, the positions of the centers of curvature, and each of these spherical concave surfaces 17,
By restricting the radius of curvature of 19, it is possible to prevent the displacement of the retainer in the axial direction and to optimize the intake of the lubricant into the pocket 9 in the case of the first example described above. Is the same as

As a modification of the above-described first example, the central portion of the pocket 9 may be replaced by a radial cylindrical surface whose central axis is the diameter direction of the main portion 7 instead of the spherical concave surface 17. Also, the inner peripheral surfaces of the elastic pieces 12, 12 are replaced with the second spherical concave surfaces 17, 19, instead of the axial cylindrical surfaces 18, 18.
May be a conical concave surface having the same rolling center axis α as its center. Further, when the present invention is embodied in a cage incorporated in a small-diameter radial ball bearing like a miniature bearing, a remarkable effect can be obtained. Therefore, the present invention
It is common practice to use a crown retainer made of a synthetic resin, which is generally used as a retainer for a small-diameter radial ball bearing. However, even if the present invention is implemented with a waveform holder made of a metal plate, a certain effect can be obtained. Of course, such a waveform holder can also be an object of the present invention.

Further, when practicing the present invention, the pocket
Pitch circle diameter (of the curvature of the axial cylindrical surface 18, 18)
The diameter of the cylindrical surface connecting the central axes) and the pitch circle diameter of the ball
It is not always necessary to match them. For example, as shown in FIG.
And the pitch circle P of the pocket 9 ₈Is the pitch circle P of ball 5_FiveYo
May also be positioned outside the bridge. Both pitch circles like this
P ₈, P_FiveIf you shift each other, each axial cylindrical surface 1
The distance between the opening edges of the balls 8 and 18 and the rolling surface of the ball 5
Is larger on the outer diameter side and smaller on the inner diameter side. And each
Lubricants at the opening edges of the axial cylindrical surfaces 18, 18
By adjusting the scraping effect, lubricant into the pocket 5
The feed amount of the bearing to reduce cage noise and reduce bearing torque.
Can be achieved. In addition, both pitch circles P₈, P_FiveBig and small
The relationship can be reversed from that of FIG.

As described above, the following grease composition is sealed in a rolling bearing incorporating a cage having an axial cylindrical surface. The grease base oil sealed in the rolling bearing contains ester oil as an essential component. This 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 polyhydric alcohol and a monobasic acid. Hindered ester oil obtained from the reaction is suitably used, and considering heat resistance, it is selected from aromatic ester oils and hindered ester oils, and it is particularly preferable to use them alone or as a mixture. As diester oils, dioctyl adipate (DOA), diisobutyl adipate (DIBA), dibutyl adipate (DBA), dioctyl azelate (DOZ), dibutyl sebacate (DBS), dioctyl sebacate (D
OS), methyl acetyl ricinoleate (MAR-N)
And the like. Examples of the aromatic ester oil include trioctyl trimellitate (TOTM), tridecyl trimellitate, and tetraoctyl pyromellitate. Hindered ester oils include those obtained by appropriately reacting the following polyhydric alcohols and monobasic acids. The monobasic acid reacted with the polyhydric alcohol may be used alone or in combination. Further, it may be used as a complex ester which is an oligoester of a polyhydric alcohol and a mixed fatty acid of a dibasic acid / monobasic acid.

Examples of polyhydric alcohols include trimethylolpropane (TMP), pentaerythritol (PE),
Examples include dipentaerythritol (DPE), neopentyl glycol (NPG), 2-methyl-propyl-1,3-propanediol (MPPD).

As the monobasic acid, C _{4 to} C ₁₈ monovalent fatty acids are mainly used. Specifically, for example, butyric acid, valeric acid, caproic acid, caprylic acid, enanthic acid, pelargonic acid, capric acid, undecanoic acid, lauric acid, mystyric acid, palmitic acid, tallow fatty acid, sularic acid, caproleic acid, undecylenic acid, Lindelic acid, tuzunic acid, fiseteric acid, myristoleic acid, palmitoleic acid,
Examples include petroselinic acid, oleic acid, elaidic acid, asclepic acid, vaccenic acid, sorbic acid, linoleic acid, linolenic acid, savininic acid, and ricinoleic acid. The above ester oil is desirably at least 50% by weight based on the total amount of the base oil. If the ester oil content is less than 50% by weight, sufficient high-temperature durability, particularly at low speeds, cannot be obtained. Further, other than the above, synthetic hydrocarbon oil and ether oil can be blended as base oil components.

Examples of the synthetic hydrocarbon oils include poly-α-olefin oils and cooligomers of α-olefins and ethylene. Examples of the ether oil include phenyl ether oils derived from a C12 to C20 (di) alkyl chain of diphenyl, triphenyl, and tetraphenyl. In particular, in consideration of high-temperature high-speed durability, (di) alkyl polyphenyl ether oil is preferable. These compounding ratios are within 50% by weight.

Base oil viscosity: 40 ° C. Kinematic viscosity: 30 to 150 m
It is in the range of m ² / s, but is particularly preferably 40 to 150 mm ² / s. If the kinematic viscosity is less than 30 mm ² / s, the film-forming property is not sufficient especially at low speed rotation, and if it exceeds 150 mm ² / s, the bearing cage sound at the time of startup at low temperatures is not preferable.

As the thickener used in the grease composition of the present invention, a lithium salt of a fatty acid containing no hydroxyl group and a lithium salt of a fatty acid containing a hydroxyl group are used alone or in combination. Lithium soap containing a hydroxyl group has a high affinity with the base oil due to the action of the hydroxyl group contained in the structure, has good dispersibility, and can improve the acoustic characteristics of a bearing to which the grease composition is applied. In addition, by using a soap having no hydroxyl group in the structure, the soap structure is more stable, a dense soap structure is obtained, and the durability under high temperature conditions is improved.

When a mixture of lithium soap containing no hydroxyl group and lithium soap containing a hydroxyl group is used, the content of the lithium soap containing no hydroxyl group is in the range of 0 to 70 wt%, and the content of the lithium soap containing the hydroxyl group is in the range of 30 to 100 wt%. It is preferable to mix them. In particular, the content of the lithium salt of the fatty acid having no hydroxyl group is preferably in the range of 0 to 60 wt%, and the content of the lithium soap having the hydroxyl group is preferably in the range of 40 to 100 wt%. The thickener is contained in the grease composition in an amount of 5% by weight or more and less than 20% by weight, preferably 5 to 18% by weight. If the thickener is less than 5% by weight, the consistency increases, the grease softens, and the grease leaks from the bearing, and sufficient acoustic characteristics cannot be obtained. If the content is 20 wt% or more, the torque and the acoustic characteristics at high temperatures are inferior.

The lithium salt of a C ₁₂ -C ₂₄ fatty acid containing no hydroxyl group is not particularly limited, but lithium laurate (C ₁₂ ), myristyl phosphate (C ₁₄ ), lithium palmitate (C ₁₆ ), margarine Lithium (C ₁₇ ) acid, lithium stearate (C ₁₈ ), lithium arachidate (C ₂₀ ), lithium behenate (C ₂₂ ), lithium lignoserate (C ₂₄ ), lithium tallow fatty acid, and the like. And lithium tallow fatty acid.

The lithium salt of a C ₁₂ -C ₂₄ fatty acid containing a hydroxyl group is not particularly limited, but includes lithium 9-hydroxystearate, lithium 10-hydroxystearate, lithium 12-hydroxystearate,
Examples thereof include lithium 10-dihydroxystearate, lithium ricinoleate, and lithium ricinoelaidate, and preferably lithium 12-hydroxystearate.

The grease composition contains the above base oil and a thickener. However, as long as the preferable properties are not impaired, in addition to the base oil and the thickener, a rust inhibitor, an antioxidant, a metal inactive agent, and the like. Agents, extreme pressure agents, antiwear agents, viscosity index improvers and the like can be added alone or in combination of two or more. These may be any of known ones. For example, other thickeners such as metal soaps made of metal salts other than lithium, benton and silica gel; antioxidants such as amine type, phenol type, sulfur type and zinc dithiophosphate;
Fatty agents such as fatty acids and vegetable oils; Rust inhibitors such as petroleum sulfonate, dinonylnaphthalenesulfonate, sorbitan ester; Metal deactivators such as benzotriazole and sodium nitrite; Improvement of viscosity index of polymethacrylate, polyisobutylene, polystyrene, etc. Agents and the like can be added alone or in combination of two or more.

The present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples. Examples 1 to 5 and Comparative Examples 1 to 9 Each grease composition was prepared by mixing a thickener and a base oil as shown in Tables 1 to 3. The total amount of lithium stearate, lithium 12-hydroxystearate (described as lithium 12-OH stearate in the table) and the base oil was 950 g, which was added to an antioxidant, a rust inhibitor and a metal deactivator. 50 in total
g was added to obtain a grease composition having a total amount of 1000 g. or,
The base oil viscosity (40 ° C.) is also shown in the table. Each grease composition was applied to a test bearing, and (1) bearing acoustic durability test and (2)
The bearing cage was subjected to sound measurement.

(1) Bearing acoustic durability test <Used cages: all made of synthetic resin>-Examples 1 to 5 and Comparative Examples 8 to 9 are axial cylindrical cages shown in Fig. 3.-Comparative Examples 1 to 5 are: As shown in Japanese Patent Application Laid-Open No. 8-338434, a cage having chamfered peripheral edges of pocket openings at eight locations in the circumferential direction. Comparative Examples 6 and 7 have a conventional shape and chamfered peripheral edges of the opening. Unwashed cage As a test bearing, rotary cleaning was performed twice with petroleum benzene,
It was allowed to stand at room temperature, dried and completely degreased, and used were each having an inner diameter of 6 mm, an outer diameter of 15 mm, and a width of 5 mm to which the above three types of retainers were attached. Using a syringe, 0.05 g of each grease composition was sealed in the test bearing and sealed with a non-contact metal seal (Z type).

The test bearings were tested for 16 greases per grease composition.
Each was prepared and attached to the grease life tester shown in FIGS. 7 and 8. This grease life tester has a housing 2
0, the test bearing is placed in the rubber belt 21 and the pulley 2
The motor 2 is rotated by the power of the motor 23 via the motor 2. Then, the grease life tester was housed in a thermostatic chamber adjusted to 120 ° C., and the inner ring was set at 300 rpm and 5600 rpm.
1000 rpm (both with an axial load of 2 kgf)
Rotated for hours. After 1000 hours, the bearing was taken out, and the acoustic characteristics of the bearing were examined according to the following evaluation criteria. The acoustic measurement of the bearing was performed using an Anderon meter, and the acoustic characteristic was determined by comparing the bearing Anderon value immediately after the grease composition was sealed and the Anderon value of the bearing after 1000 hours of rotation. Judgment result is "○" without deterioration of acoustic characteristics,
Table 1 shows “△” with a slight decrease and “×” with a decrease.
To 3.

[0031]

[Table 1]

[0032]

[Table 2]

[0033]

[Table 3]

As is apparent from Tables 1 to 3, the test bearings of the examples have excellent acoustic characteristics under low-speed rotation and high-speed rotation.

Further, in order to confirm the superiority of the axial cylindrical cage of the present invention, an acoustic life test was performed for up to 3000 hours under the above-mentioned conditions in comparison with a chamfered cage. Experimental examples 1 and 2 used an axial cylindrical retainer,
C. Base oil viscosity of about 35 and 80 mm ² / s, Experimental Examples 3-4
The experiment was performed using a grease composition having a base oil viscosity of about 35 and 80 mm ² / s at 40 ° C. using a chamfered cage.
The results are shown in Table 4.

[0036]

[Table 4]

As is clear from Table 4, it is understood that the use of the axial cylindrical retainer of the present invention greatly improves the acoustic life of the bearing.

(2) Measurement of sound of bearing cage As a test bearing, rotary cleaning was performed twice with petroleum benzene,
It was allowed to stand at room temperature, dried and completely degreased, and used those having an inner diameter of 8 mm, an outer diameter of 22 mm, and a width of 7 mm to which the above three types of cages were respectively attached. 0.16 g of each grease composition shown in Tables 1 to 3 was sealed in the test bearing using a syringe, and sealed with a non-contact metal seal (Z type). Five test bearings were prepared for each grease composition. And
The test bearing was rotated at 1800 rpm and the cage sound at 0 ° C. and −10 ° C. was measured using a frequency analyzer.
The results of the determination are shown in Tables 1 to 3, with no occurrence of cage sound “○”, slight cage sound “△”, and large cage sound “×”. As is clear from Tables 1 to 3, it is understood that the test bearings of the examples do not generate cage noise at low temperatures.
In particular, in the test bearings of Comparative Examples 1 to 5 using the chamfered cage, the cage noise was generated under a more severe condition of −10 ° C., whereas the test of the example having the axial cylindrical surface was performed. No bearing noise was generated in the bearing, indicating that the rolling bearing of the present invention can withstand use at lower temperatures.

[0039]

As described above, the rolling bearing of the present invention is provided with an axial cylindrical surface to improve the flow of grease into pockets and to encapsulate grease having excellent durability at low and high temperatures. Accordingly, the acoustic characteristics at low and high temperatures are improved, the life of the acoustic characteristics at high to low speed rotation is extended, and the generation of cage noise at low temperatures can be suppressed.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a rolling bearing of the present invention.

FIG. 2 is a perspective view showing a crown type cage which is an example of a cage incorporated in the rolling bearing of the present invention.

FIG. 3 is a perspective view of a peripheral portion of a pocket showing a first example of a crown type retainer.

FIG. 4 is a cross-sectional view taken along a line AA in FIG. 3, showing a state where a ball is held in a pocket. FIG. 3A shows a configuration in which the first spherical concave surface and the second spherical concave surface are shifted from each other in center, and FIG. 3B shows a configuration in which the centers of both spherical concave surfaces are matched.

FIG. 5 is a perspective view of a peripheral portion of a pocket showing a second example of the crown type cage.

FIG. 6 is a diagram for explaining a pocket pitch.

FIG. 7 is a schematic view of an apparatus used for a bearing acoustic durability test.

8 is a cross-sectional view of a main part for describing a rotation mechanism of the apparatus shown in FIG.

[Explanation of symbols]

 2 inner ring 4 outer ring 5 ball (rolling element) 6 seal plate 7 retainer (crown type) 8 main part 9 pocket 10 elastic piece 17 spherical concave surface 18, 18a axial cylindrical surface 19 second spherical concave surface 20 housing 21 rubber belt 22 pulley 23 motor

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C10M 105: 32) C10N 10:02 20:02 40:02 (72) Inventor Michiharu Naka Fujisawa-shi, Kanagawa 1-50-50 Kugenuma Shinmei Nippon Seiko Co., Ltd. (72) Inventor Yasuyuki Muto 1-5-50 Kugenuma Shinmei 1-chome, Fujisawa City, Kanagawa Prefecture Nippon Seiko Co., Ltd. (72) Inventor Hironori Suzuki Kugenuma Shinmei, Fujisawa City, Kanagawa Prefecture F-term (reference) 1-5-5 Nippon Seiko Co., Ltd. 3J101 AA02 AA32 AA42 AA52 AA62 AA72 BA34 BA44 CA11 CA32 EA64 FA01 GA60

Claims (1)

[Claims] 1. An axial cylindrical surface including at least a part of the inner surface of each pocket of a retainer including a peripheral opening edge of the retainer, and having a rolling center axis of a rolling element held in each pocket as its central axis. A rolling bearing comprising a plurality of rolling elements rotatably held between an inner ring and an outer ring via the retainer, and a lithium salt of a fatty acid containing no hydroxyl group and a fatty acid containing a hydroxyl group. A thickener selected from a lithium salt and a mixture thereof;
A rolling bearing, characterized in that a grease composition containing mm ² / s and a base oil containing an ester oil as an essential component is enclosed.