JP2008032079A - Grease-sealed rolling bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a grease-sealed rolling bearing which can accurately keep the sealing ability of the sealed type rolling bearing, and also can effectively prevent the peeling of a rolling surface caused by hydrogen embrittlement. <P>SOLUTION: In the grease-sealed rolling bearing, a bearing space between an inner race 1 and an outer race 2 is sealed by bringing a seal lip 5d formed of an elastic member of a contact seal 5 into contact with a seal sliding surface 1b formed on the inner race 1 or the outer race 2, and grease is sealed in the bearing space which is formed by compounding base grease composed of base oil and a viscosity additive, and an additive agent. The pressing force P of the seal lip 5d is set to be 1.6 N or larger. Further, the grease contains aluminum powder and at least one aluminum base additive agent selected from aluminum compounds, and the ratio of the combination of the aluminum base additive agent is 0.05 to 10 pts.wt. to 100 pts.wt. of the base grease. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a grease-sealed rolling bearing, and in particular, a grease-sealed type for a rolling bearing for an automotive electrical component such as an alternator, an electromagnetic clutch for a car air conditioner, an intermediate pulley, and an electric fan motor, an auxiliary machine, and a rolling bearing for a motor. It relates to rolling bearings.

Contact seals are used for rolling bearings that are used in pulleys for automobile accessories and electromagnetic clutches in compressors for air conditioners and require high sealing performance against the intrusion of muddy water from the outside and the leakage of lubricants such as grease from the inside. A sealing type rolling bearing is used in which the seal lip is pressed against a seal sliding contact surface provided on an inner ring or an outer ring to seal a bearing space between the inner ring and the outer ring. The seal lip of the contact seal is made of an elastic member such as rubber and has a tightening margin with respect to the seal sliding contact surface. Usually, the seal lip is provided at a portion extending forward from the core of the elastic member fixed to the core. Yes.
In this type of sealed rolling bearing, the contact seal is fixed to the outer ring side, the seal sliding contact surface is provided on the side wall of the circumferential groove formed on the outer peripheral surface of the inner ring, and the seal lip of the contact seal is formed on the seal sliding contact surface. Many of them are pressed from the axial direction (see, for example, Patent Document 1 and Patent Document 2).

In Patent Document 1, the axial thickness B of the seal lip extending from the core bar is set to 0.2 to 0.4 mm, and the ratio between the radial length A and the axial thickness B of the seal lip is set as follows. A certain A / B is set so that 4.5 ≦ A / B ≦ 7, and the rigidity of the seal lip is moderated, thereby improving the followability of the seal lip with respect to the seal sliding contact surface and improving the contact state of the seal lip. Propose to stabilize.
Further, in Patent Document 2, the pressing force of the seal lip against the seal sliding contact surface (hereinafter referred to as “pressing force against the seal sliding contact surface” is denoted as P) and the axial tightening margin L of the seal lip. (Hereinafter referred to as “Axial tightening allowance” is denoted as L) P / L is 2.9 to 9.8 N / mm, and L of the seal lip is 1 to 3% of the diameter of the ball as the rolling element Thus, it has been proposed to make the elastic member less likely to be elastically deformed, which leads to a decrease in the sealing performance, and to ensure the sealing performance.

As described in Patent Document 1, a sealed-type rolling bearing in which the size of the seal lip is defined and its rigidity is moderate does not directly or indirectly define the tightening allowance of the seal lip. Therefore, there is a problem that the sealability cannot be ensured accurately. Further, the shape of the seal lip, such as that described in Patent Document 2, for example, is not constant because the axial thickness B is not constant and has a problem of lack of versatility.
On the other hand, as described in Patent Document 2, the seal-type rolling bearing in which the seal lip P / L and the seal lip L are defined changes the seal lip P when the seal lip L changes. There is a problem that the management of putting the seal lip L and P / L within the specified range becomes complicated. Further, when the seal lip L is close to the lower limit, even if the seal lip P is small, the seal lip P / L may fall within the specified range, and the sealing performance may not be ensured. Furthermore, since the L of the seal lip is defined as a ratio to the diameter of the ball, there is a problem that can be applied only to ball bearings.

Further, grease is mainly used for lubrication of these rolling bearings. However, severe use conditions such as high-speed rotation at high temperatures cause a problem in that specific peeling accompanied by a change in white structure occurs at an early stage on the rolling surface of the rolling bearing.
This specific exfoliation is different from the exfoliation from the inside of the rolling contact surface caused by normal metal fatigue, and is considered to be due to hydrogen embrittlement caused by hydrogen due to a fracture phenomenon that occurs from a relatively shallow surface of the rolling surface. Yes. As a method for preventing such a specific peeling phenomenon accompanied by a white tissue change that occurs at an early stage, for example, a method of adding a passivating agent to grease is known (see Patent Document 3). A method of adding bismuth dithiocarbamate to a grease composition is known (see Patent Document 4).
However, in recent years, electrical components and accessories in automobiles, motors in industrial machinery, etc., have increasingly used rolling bearings, such as frequent high-speed operation-sudden deceleration operation-rapid acceleration operation-sudden stop at high temperatures. However, the method of adding a passivating agent or bismuth dithiocarbamate has become insufficient as a measure for preventing the peeling phenomenon. In particular, when the sealing performance described above is not sufficient, there is a problem that grease leaks and this peeling phenomenon is more likely to occur.
Japanese Patent No. 3062673 (FIGS. 1 and 2) JP 2001-140907 A (FIGS. 1 to 4) JP-A-3-210394 JP-A-2005-42102

  The present invention has been made to cope with such a problem. The present invention makes it possible to accurately ensure the sealing performance of a sealed rolling bearing with simple and versatile regulations, and in a grease-filled bearing, the rolling due to hydrogen embrittlement. An object is to provide a grease-sealed rolling bearing capable of effectively preventing separation on the running surface.

  The grease-sealed rolling bearing of the present invention seals the bearing space between the inner ring and the outer ring by pressing a seal lip formed of an elastic member of a contact seal against a seal sliding contact surface provided on the inner ring or the outer ring. In a grease-sealed rolling bearing in which a base grease consisting of a base oil and a thickener is mixed with an additive, and grease is sealed, the seal lip P is set to 1.6 N or more, and the grease Contains at least one aluminum-based additive selected from aluminum powder and aluminum compound, and the mixing ratio of the aluminum-based additive is 0.05 to 10 parts by weight with respect to 100 parts by weight of the base grease. To do.

The surface roughness of the seal sliding contact surface is characterized in that R max is 2.0 μm or less.
Further, the seal sliding contact surface is provided on a side wall of a circumferential groove extending in the circumferential direction of the outer peripheral surface of the inner ring, and the seal lip is pressed against the seal sliding contact surface provided on the side wall of the circumferential groove from the axial direction. It is characterized by that.

The aluminum compound is at least one compound selected from aluminum carbonate and aluminum nitrate.
The thickener is a urea-based thickener.
The base oil is at least one oil selected from alkyl diphenyl ether oil and poly-α-olefin oil.

  In the grease-sealed rolling bearing of the present invention, by setting the seal lip P to 1.6 N or more, only the pressing force is defined so as to indirectly include the seal lip L, and the seal slidable contact surface of the seal lip In order to ensure good contact with the product, and to ensure the sealing performance of sealed rolling bearings with simple and versatile regulations, grease containing an aluminum additive is sealed. It can contribute to the lubrication of the raceway without leakage. In addition, the aluminum compound blended with grease reacts on the frictional wear surface or the new metal surface exposed by wear, and an aluminum coating is formed on the bearing rolling surface along with iron oxide. Occurrence of peculiar peeling due to can be suppressed. As a result, it is possible to dramatically improve the life of the bearing. For this reason, it can be suitably used as a rolling bearing for automotive electrical components such as alternators, car air conditioner electromagnetic clutches, intermediate pulleys, and electric fan motors, and auxiliary machines.

  In addition, by making the surface roughness of the above-mentioned seal sliding surface Rmax 2.0 μm or less, preferably 1.2 μm or less, it is possible to prevent an increase in torque loss due to friction with the seal lip and to suppress wear of the seal lip. Thus, the seal lip P can be stably held.

In order to obtain a grease-sealed rolling bearing capable of sufficiently preventing the deterioration of the sealing performance and effectively preventing separation on the rolling surface due to hydrogen embrittlement in the grease-filled bearing, an earnest study was conducted. As a result of investigation, after a grease containing at least one aluminum-based additive selected from an aluminum powder and an aluminum compound is sealed in a base grease composed of a base oil and a thickener, the seal lip P of the rolling bearing is set to 1.6. It has been found that a grease-sealed rolling bearing with a seal member that is set to N or more and has a sealing member that defines only the pressing force so as to indirectly include the tightening margin of the seal lip dramatically improves the bearing life.
By setting the seal lip P to 1.6 N or more, only the pressing force is specified so as to indirectly include the tightening margin of the seal lip, and a good contact state with the seal slidable contact surface of the seal lip is ensured. The sealability of the sealed rolling bearing can be ensured accurately with simple and versatile regulations. This prevents activation of the rolling contact surface due to wear caused by oil film breakage due to grease leakage due to grease leakage, or activation of the bearing rolling surface due to wear caused by early grease deterioration due to grease reduction. it can. Furthermore, even if the bearing rolling surface is activated, that is, when the bearing rolling surface is exposed to a frictional wear surface or a new metal surface exposed due to wear, the aluminum compound blended in the grease reacts, and the aluminum oxide is coated with the iron oxide. Can be generated on the rolling surface of the bearing, and the occurrence of specific delamination accompanied by white structure change can be suppressed.
As described above, in the present invention, the effect of contributing to the lubrication of the bearing ring without leaking the enclosed grease by the action of the improvement of the sealing performance and the like and the formation of the aluminum coating on the bearing rolling surface, and the rolling Rather than individually pulling out the effect of preventing specific exfoliation with white tissue changes that occur on the running surface, it is possible to perform specific exfoliation with white tissue changes that occur on the rolling surface by overlapping each action. It is considered that the effect to prevent can be exhibited synergistically and the bearing life is dramatically improved. The present invention is based on such knowledge.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a partially omitted longitudinal sectional view showing an embodiment of a grease-sealed rolling bearing. As shown in FIG. 1, this grease-sealed rolling bearing has a bearing space in which a rolling element 3 is held by a cage 4 between an inner ring 1 and an outer ring 2, and is provided on an inner peripheral surface of the outer ring 2. It is a deep groove ball bearing sealed with a contact seal 5 fixed in the groove 2a. Grease 6 is sealed at least around the rolling element 3.
FIG. 2 is an enlarged cross-sectional view showing a main part of FIG. As shown in FIG. 2, the contact seal 5 comprises a metal core 5a and an elastic member 5b. A neck portion 5c is provided at a portion of the elastic member 5b extending from the metal core 5a first, and a seal lip 5d is provided at the tip. It is provided and pressed against the seal sliding contact surface 1b provided on the side wall of the circumferential groove 1a extending in the circumferential direction on the outer circumferential surface of the inner ring 1 from the outside in the axial direction. The pressing force of the seal lip 5d against the seal sliding contact surface 1b is set to 1.6 N or more. The surface roughness R max of the seal sliding contact surface 1b is 2.0 μm or less, preferably 1.2 μm or less.

  In the embodiment described above, the sealed type rolling bearing is a deep groove ball bearing, but the sealed type rolling bearing according to the present invention can also be used for other types of rolling bearings such as other ball bearings and roller bearings. .

The aluminum-based additive added to the grease is at least one selected from aluminum powder and aluminum compound. Aluminum compounds include aluminum carbonate, aluminum sulfide, aluminum chloride, aluminum nitrate and its hydrate, aluminum sulfate, aluminum fluoride, aluminum bromide, aluminum iodide, aluminum oxide and its hydrate, aluminum hydroxide, selenium Aluminum fluoride, aluminum telluride, aluminum phosphate, aluminum phosphide, lithium aluminate, magnesium aluminate, aluminum selenate, aluminum titanate, aluminum zirconate and other inorganic aluminum, aluminum benzoate, aluminum citrate and other organic aluminum Is mentioned. These aluminum-based additives may be added to the grease alone or in combination of two or more.
Particularly preferable in the present invention is an aluminum powder having a high extreme pressure effect because it is excellent in heat resistance and hardly decomposes thermally.

The mixing ratio of the aluminum-based additive is 0.05 to 10 parts by weight with respect to 100 parts by weight of the base grease. That is, (1) when the aluminum additive is only aluminum powder, 0.05 to 10 parts by weight of aluminum powder with respect to 100 parts by weight of the base grease, and (2) when the aluminum additive is only aluminum compound, 0.05 to 10 parts by weight of aluminum compound per 100 parts by weight of grease, and (3) when aluminum additive is aluminum powder and aluminum compound, aluminum powder and aluminum compound are added to 100 parts by weight of base grease. Combine 0.05 to 10 parts by weight.
If the blending ratio of the aluminum additive is less than this blending range, peeling on the rolling surface due to hydrogen embrittlement cannot be effectively prevented. Moreover, even if it exceeds the said range, the peeling prevention effect does not improve any more.

Base oils that can be used in the present invention include mineral oils such as spindle oil, refrigerator oil, turbine oil, machine oil, dynamo oil, highly refined mineral oil, liquid paraffin, polybutene, GTL oil synthesized by the Fischer-Tropsch method, poly- Hydrocarbon synthetic oil such as α-olefin oil, alkylnaphthalene, alicyclic compound, or natural oil, polyol ester oil, phosphate ester oil, polymer ester oil, aromatic ester oil, carbonate ester oil, diester oil, Non-hydrocarbon synthetic oils such as polyglycol oil, silicone oil, polyphenyl ether oil, alkyldiphenyl ether oil, alkylbenzene oil, and fluorinated oil can be used.
Among these, it is preferable to use alkyl diphenyl ether oil or poly-α-olefin oil excellent in heat resistance and lubricity.

Thickeners that can be used in the present invention include benton, silica gel, fluorine compounds, lithium soap, lithium complex soap, strong lucium soap, calcium complex soap, aluminum soap, aluminum complex soap, and other soaps, diurea compounds, polyurea compounds, etc. These urea compounds are mentioned.
Of these, urea compounds are desirable in view of heat resistance, cost, and the like.

  A urea compound is obtained by reacting an isocyanate compound and an amine compound. In order not to leave a reactive free radical, the isocyanate group of the isocyanate compound and the amino group of the amine compound are preferably blended so as to be approximately equivalent.

  A diurea compound is obtained by reaction of a diisocyanate and a monoamine, for example. Examples of the diisocyanate include phenylene diisocyanate, tolylene diisocyanate, diphenyl diisocyanate, diphenylmethane diisocyanate, octadecane diisocyanate, decane diisocyanate, hexane diisocyanate, etc., and monoamines include octylamine, dodecylamine, hexadecylamine, stearylamine, Examples include oleylamine, aniline, p-toluidine, cyclohexylamine and the like. The polyurea compound can be obtained, for example, by reacting diisocyanate with a monoamine or diamine. Examples of the diisocyanate and monoamine include those similar to those used for the production of the diurea compound. Examples of the diamine include ethylenediamine, propanediamine, butanediamine, hexanediamine, octanediamine, phenylenediamine, tolylenediamine, xylenediamine, And diaminodiphenylmethane.

By adding a thickener such as a urea compound to the base oil, a base grease for blending the aluminum additive and the like can be obtained. A base grease using a urea compound as a thickener is prepared by reacting an isocyanate compound and an amine compound in a base oil.
The blending ratio of the thickener in 100 parts by weight of the base grease is 1 to 40 parts by weight, preferably 3 to 25 parts by weight. If the content of the thickener is less than 1 part by weight, the thickening effect will be reduced, making it difficult to make grease, and if it exceeds 40 parts by weight, the resulting base grease will be too hard and the desired effect will not be obtained. Become.

  In addition to the aluminum-based additive, a known grease additive may be included as necessary. Examples of the additives include antioxidants such as organic zinc compounds, amines, and phenolic compounds, metal deactivators such as benzotriazole, viscosity index improvers such as polymethacrylate and polystyrene, molybdenum disulfide, and graphite. Examples include solid lubricants, metal sulfonates, rust inhibitors such as polyhydric alcohol esters, friction reducers such as organic molybdenum, oil agents such as esters and alcohols, and antiwear agents such as phosphorus compounds. These can be added alone or in combination of two or more.

Reference example 1
A sealed deep groove ball bearing shown in FIG. 1 was prepared in which the seal lip P of the rolling bearing was set to 1.6 N or more. The ratio a / b of the radial length a including the neck portion 5c and the seal lip 5d of the contact seal 5 shown in FIG. 2 and the axial thickness b of the neck portion 5c, that is, the seal lip defined in Patent Document 1 is shown. The value corresponding to the ratio A / B of the radial length A and the axial thickness B was 3.2. Further, the surface roughness R max of the seal sliding contact surface was set to 1.2 μm or less. P of the seal lip was measured by the compression test shown below.
Next, this sealed deep groove ball bearing was subjected to a muddy water resistance test described below, and the amount of muddy water entering the bearing space was measured in an environment where muddy water was sprayed. These results are shown in FIG.

<Compression test>
FIG. 3 is a longitudinal sectional view showing a method for measuring the seal lip P of the contact seal of FIG. FIG. 4 is an enlarged cross-sectional view showing a main part of FIG. As shown in FIGS. 3 and 4, the outer ring 2 fitted with the contact seal 5 of the sealed deep groove ball bearing of Reference Example 1 is set horizontally on the gantry 8 of the compression tester 7, and the contact seal is formed by the pressure head 9. P of the seal lip was determined by measuring the load when the seal lip 5d of 5 was pressed by a vertical displacement amount corresponding to a predetermined axial interference.

<Muddy water resistance test>
The sealed deep groove ball bearing of Reference Example 1 described above was attached to a rotating test machine in an environment where muddy water was sprayed, and a muddy water resistance test was conducted to investigate the amount of muddy water entering the bearing space. The amount of muddy water permeation was determined by measuring the mass increase W of the bearing before and after the test. The test conditions are as follows.
・ Muddy water: Kanto loam powder JIS 8 types (mud concentration 5% by mass)
・ Rotation speed: 2000 rpm
・ Test time: 3 hours

Reference Comparative Example 1
A sealed deep groove ball bearing was prepared in the same manner as in Reference Example 1 except that the seal lip P / L was 4.8 to 8.8 N / mm and the seal lip P was less than 1.6 N. The P of the seal lip was measured by the compression test described above.
Next, this sealed deep groove ball bearing was subjected to the muddy water resistance test described above, and the amount of muddy water entering the bearing space was measured in an environment where muddy water was sprayed. These results are also shown in FIG.

  As shown in FIG. 5, in Reference Example 1 in which the seal lip P is set to 1.6 N or more, the ratio a / b corresponding to the ratio A / B between the radial length A and the axial thickness B of the seal lip is as follows. Although it is outside the scope of the invention described in Patent Document 1, it can be seen that no significant increase in the mass W of the bearing is observed, and that it has excellent sealing properties. On the other hand, in Reference Comparative Example 1 in which the seal lip P is less than 1.6 N, the seal lip P / L is within the scope of the invention described in Patent Document 2, but both are the mass of the bearing. Increase amount W is recognized remarkably and sufficient sealing performance is not secured.

Reference Example 2 to Reference Example 9
In half of the base oil shown in Table 1, 4,4-diphenylmethane diisocyanate (Millionate MT manufactured by Nippon Polyurethane Industry Co., Ltd., hereinafter referred to as MDI) is dissolved in the ratio shown in Table 1, and the remaining half of the base oil is dissolved. A monoamine that was twice the equivalent of MDI was dissolved. The respective blending ratios and types are shown in Table 1.
A solution in which monoamine was dissolved was added while stirring the solution in which MDI was dissolved, and then the reaction was continued for 30 minutes at 100 ° C. to 120 ° C. to produce a diurea compound in the base oil.
To this, an aluminum-based additive and an antioxidant were added in the proportions shown in Table 1, and the mixture was further stirred at 100 to 120 ° C. for 10 minutes. Thereafter, the mixture was cooled and homogenized with three rolls to obtain a grease.
In Table 1, the synthetic hydrocarbon oil used as the base oil is Shinflud 601 manufactured by Nippon Steel Chemical Co., Ltd. with a kinematic viscosity of 30 mm ² / sec at 40 ° C, and the alkyldiphenyl ether oil is Matsumura with a kinematic viscosity of 97 mm ² / sec at 40 ° C. Moresco High Lube LB100 manufactured by Petroleum Corporation was used. Moreover, the hindered phenol by Sumitomo Chemical Co., Ltd. was used for antioxidant.
A sealed deep groove ball bearing having a seal lip P / L of 4.8 to 8.8 N / mm and a seal lip P of less than 1.6 N was prepared, and the obtained grease was sealed, and a rapid acceleration / deceleration test was conducted. Test methods and test conditions are shown below. The results are shown in Table 1.

<Rapid acceleration / deceleration test>
An alternator, which is an example of an electrical accessory, was simulated, the above grease was enclosed in a rolling bearing, and a rapid acceleration / deceleration test was performed. The rapid acceleration / deceleration test conditions are as follows: the load load on the pulley attached to the tip of the rotating shaft is set to 1960 N, the operating speed is set to 0 rpm to 18000 rpm, and a current of 0.1 A flows through the test bearing. The test was conducted. Then, abnormal peeling occurred in the bearing, and the time when the vibration of the vibration detector exceeded the set value and the generator stopped (peeling life time, h) was measured. The test was terminated after 500 hours.

Example 1
In Reference Example 2, a sealed deep groove ball bearing having a seal lip P set to 1.6 N or more was prepared and evaluated by performing the same test as in Reference Example 2. The results are also shown in Table 1.

Reference Comparative Example 2 to Reference Comparative Example 4
A sealed deep groove ball bearing having a seal lip P / L of 4.8 to 8.8 N / mm and a seal lip P of 1.6 N or more was prepared and evaluated by conducting the same test as in Reference Example 2. The results are also shown in Table 1.

As shown in Table 1, in Reference Examples 2 to 9, all of the rapid acceleration / deceleration tests showed excellent results of 400 hours or longer (peeling life time). This is considered to be because the specific exfoliation accompanied by the white structure change due to hydrogen embrittlement generated on the rolling surface can be effectively prevented by adding the aluminum-based additive at a predetermined ratio.
In Example 1 where the seal lip P was set to 1.6 N or more and good contact with the seal sliding contact surface of the seal lip was secured, the rapid acceleration / deceleration test was 500 hours or more (peeling life time). It was possible to more effectively prevent specific exfoliation accompanied by a change in white structure than in Reference Example 5 in which the grease had the same composition. This is considered to be because grease leakage due to a decrease in sealing performance was prevented in addition to the effect of the aluminum-based additive.
Further, as shown in Reference Comparative Example 2 to Reference Comparative Example 4, even when the seal lip P is set to 1.6 N or more and a good contact state with the seal slidable contact surface of the seal lip is ensured, When the aluminum-based additive was not added to the grease at a predetermined ratio, the peeling occurrence life time was greatly shortened.

  The grease-sealed rolling bearing of the present invention has a white structure produced on the rolling surface due to the overlap of the respective actions, such as improvement in sealing performance and specific peeling prevention accompanied with a white structure change occurring on the rolling surface. The life of the bearing can be dramatically extended by synergistically extracting the effect of preventing specific peeling accompanied by changes. For this reason, it can be suitably used as an alternator, an electromagnetic clutch for a car air conditioner, an intermediate pulley, an automobile electrical component such as an electric fan motor, a rolling bearing for an auxiliary machine, and a motor bearing.

It is a partially omitted vertical sectional view showing an embodiment of a grease-sealed rolling bearing. It is sectional drawing which expands and shows the principal part of FIG. It is a longitudinal cross-sectional view which shows the method to measure P of the seal lip of the contact seal of FIG. It is sectional drawing which expands and shows the principal part of FIG. It is a graph which shows the result of a muddy water resistance test.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inner ring 1a Circumferential groove 1b Seal sliding contact surface 2 Outer ring 2a Locking groove 3 Rolling body 4 Cage 5 Contact seal 5a Core metal 5b Elastic member 5c Neck part 5d Seal lip 6 Grease 7 Compression tester 8 Base 9 Pressure head

Claims (6)

A seal lip formed of an elastic member of a contact seal is pressed against a seal sliding contact surface provided on an inner ring or an outer ring to seal a bearing space between the inner ring and the outer ring, and a base oil and a thickener are contained in the bearing space. In a grease-sealed rolling bearing in which a grease made by adding an additive to a base grease consisting of
The pressing force of the seal lip against the seal sliding contact surface is set to 1.6 N or more,
The grease contains at least one aluminum-based additive selected from aluminum powder and aluminum compound, and the mixing ratio of the aluminum-based additive is 0.05 to 10 parts by weight with respect to 100 parts by weight of the base grease. A grease-sealed rolling bearing.   2. The grease-sealed rolling bearing according to claim 1, wherein the seal sliding contact surface has a surface roughness Rmax of 2.0 [mu] m or less.   The seal slidable contact surface is provided on a side wall of a circumferential groove extending in the circumferential direction of the outer peripheral surface of the inner ring, and the seal lip is pressed against the seal slidable contact surface provided on the side wall of the circumferential groove from the axial direction. The grease-sealed rolling bearing according to claim 1 or 2, wherein   The grease-sealed rolling bearing according to claim 1, 2, or 3, wherein the aluminum compound is at least one compound selected from aluminum carbonate and aluminum nitrate.   The grease-sealed rolling bearing according to any one of claims 1 to 4, wherein the thickener is a urea-based thickener.   6. The grease-sealed rolling bearing according to claim 1, wherein the base oil is at least one oil selected from alkyl diphenyl ether oil and poly-α-olefin oil.

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