JP2008133909A - Grease-sealed double-row angular bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a grease-sealed double-row angular bearing which surely prevents the occurrence of problems of heat generation and brittle separation caused by sliding motion or the like when employing a single-row multi-point contact bearing. <P>SOLUTION: In a double-row angular bearing which includes an inner ring having two-row raceways, an outer ring respectively equipped with a raceway corresponding to each raceway of the inner ring and a plurality of rolling elements arranged in two rows between the inner and outer rings and keeps grease sealed in the circumference of the rolling element, at least, the grease is prepared by blending additive into base grease made of base oil and thickener. The grease contains at least one aluminum additive selected from among aluminum powders and an aluminum compound, wherein a ratio of blending of the aluminum additive is 0.05 to 10 pts.wt. with respect to 100 pts.wt. of the base grease. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a grease-enclosed double-row angular bearing, and more particularly, to a grease-enclosed double-row angular bearing used as a rolling bearing for automobile electrical parts such as alternators, electromagnetic clutches for car air conditioners, intermediate pulleys, and electric fan motors, and auxiliary machines.

Bearings used for automobile electrical accessories have a brittle peeling problem due to sliding between a bearing rolling surface and a bearing ring because they are used at high temperature and high speed rotation. In response to recent demands for compactness, the bearing size tends to be reduced. One type of bearing compaction, which normally uses double row bearings, may be supported by single row bearings. To compensate for the reduced life when single row bearings are used, single row multipoint contact bearings ( 4 point contact and 3 point contact) (see, for example, Patent Document 1).
For example, as shown in FIG. 2, the inner ring 12 and the outer ring 13 are integrated, and the cross-sectional shapes of the rolling surfaces 14 and 15 are the same radius of curvature with the centers 16a and 17a of the rolling surface bottom portions 16 and 17 as boundaries. Each has two centers of curvature. The positions of the two curvature centers of the inner race 12 and the outer race 13 on the rolling surfaces 14 and 15 are the same in the radial direction, and in the axial direction, the Gothic arch shape is arranged symmetrically with respect to the center of the bottom of each rolling surface. ing. Further, the rolling element 18 has a contact angle α between the inner ring 12 and the outer ring 13, and grease 19 is enclosed at least around the rolling element 18. The single row multipoint contact bearing has an axial width of about 12 to 14 mm, which is narrower than the conventional double row angular bearing (about 20 to 22 mm) and can be made compact.
However, in the case of a single-row multipoint contact bearing, since the rolling element has two rotation shafts, the rolling element becomes a sliding motion instead of a rolling motion, and this sliding motion eliminates the formation of an oil film of lubricating oil and excessive heat generation. There is a problem that a brittle exfoliation problem occurs in combination with a problem of performing and a reason described later.

In these bearings, grease is mainly used for lubrication. Due to severe conditions of use such as high-speed rotation at high temperatures, specific brittle debonding accompanied by a change in white structure occurs early on the rolling surface of the bearing, which is a problem.
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 2). A method of adding bismuth dithiocarbamate to a grease composition is known (see Patent Document 3).
However, in recent years, electrical components and accessories in automobiles, motors in industrial machines, etc. are increasingly used under high temperature conditions, such as high-speed operation-sudden deceleration operation-rapid acceleration operation-sudden stop. The method of adding a passivating agent and bismuth dithiocarbamate has become inadequate as a measure for preventing the peeling phenomenon.
JP-A-11-336795 JP-A-3-210394 JP-A-2005-42102

  The present invention has been made in order to cope with such a problem. In response to a request for downsizing, it is possible to reliably prevent a heat generation problem and a brittle peeling problem caused by a sliding motion when using a single-row multipoint contact bearing. An object of the present invention is to provide a grease-enclosed double-row angular bearing capable of supporting

  The grease-enclosed double-row angular bearing of the present invention includes an inner ring having two rows of raceways, an outer race having a raceway corresponding to each race of the inner race, and a plurality of rows arranged between the inner and outer races in two rows. A double-row angular bearing in which grease is sealed at least around the rolling element, wherein the grease comprises a base grease composed of a base oil and a thickener, and an additive. The additive contains at least one aluminum-based additive selected from aluminum powder and aluminum compound, and the blending 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. 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.
Further, the base oil is at least one oil selected from alkyl diphenyl ether oil and poly-α-olefin oil.

The grease-enclosed double-row angular bearing of the present invention is switched from a single-row multi-point contact bearing whose rolling element is mainly in sliding motion to a double-row angular bearing mainly in rolling motion in applications such as electromagnetic clutches. By encapsulating grease containing an aluminum additive, the aluminum additive added to the grease reacts on the frictional wear surface or the new metal surface exposed by wear, and aluminum is added together with iron oxide. A film is formed on the rolling surface of the bearing, and the occurrence of peeling due to hydrogen embrittlement or the like seen in bearings used in automobiles or industrial machines 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.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view showing an embodiment of a grease-enclosed double-row angular bearing.
As shown in FIG. 1, this double-row angular bearing has a bearing space in which two rows of rolling elements 3 are held by a cage 4 between an inner ring 1 and an outer ring 2 on the inner peripheral surface of the outer ring 2. This is a double-row angular contact ball bearing sealed with a contact seal 5 fixed in a locking groove. Grease 6 is sealed at least around the rolling element 3. The rolling element 3 has a contact angle β between the inner ring 1 and the outer ring 2.
The grease-enclosed double-row angular bearing of the present invention is used as a rolling bearing for automobile electrical parts, accessories, etc., for example, instead of a single-row multipoint contact bearing as shown in FIG. It is preferable that the width of the point contact bearing is as narrow as the axial width of 12 to 14 mm. At that time, the space volume inside the bearing is reduced by reducing the width dimension, and as a measure to reduce the amount of grease filled, the excess volume of the inner and outer rings of the bearing is reduced, the space volume is secured, the amount of grease filled It is preferable to employ a method for increasing the number of bearings as much as possible, a method for optimizing bearing internal specifications such as contact angle, groove curvature, ball diameter, number of balls, etc., suppressing bearing self-heating and preventing deterioration of grease.

The aluminum-based additive added to the grease used for the grease-enclosed double-row angular bearing of the present invention 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 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-based additive is less than 0.05 parts by weight, peeling on the rolling surface due to hydrogen embrittlement cannot be effectively prevented. Moreover, even if it exceeds 10 parts by weight, the anti-peeling effect will not be improved further.

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.

Examples 1 to 8
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 having a double equivalent of MDI was dissolved in the solution. 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.

  The obtained grease was subjected to a rapid acceleration / deceleration test. Test methods and test conditions are shown below. The results are shown in Table 1.

<Rapid acceleration / deceleration test>
Simulates an alternator that is an example of an electrical accessory, and the above grease is applied to an inner ring rolling bearing that supports the rotating shaft (double-row angular bearing: SUJ2, outer diameter 52 mm, inner diameter 35 mm, axial width 12 mm). Encapsulated and subjected to a rapid acceleration / deceleration test. 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 300 hours.

Comparative Examples 1 to 3
In accordance with the method according to Example 1, the base grease was prepared by selecting the thickener and the base oil at the blending ratio shown in Table 1, and the additive was further blended to obtain a grease. The obtained grease was evaluated by conducting the same test as in Example 1. The results are shown in Table 1.

  As shown in Table 1, in each example, all the rapid acceleration / deceleration tests showed excellent results of 200 hours or longer (peeling life time). This is considered to be because the specific exfoliation accompanied by the white texture change that occurs on the rolling surface can be effectively prevented by adding the aluminum-based additive at a predetermined ratio.

  The grease-enclosed double-row angular bearing of the present invention reliably prevents heat generation problems and brittle peeling problems on rolling surfaces and has a long bearing life. Therefore, automotive electrical equipment such as alternators, electromagnetic clutches for car air conditioners, intermediate pulleys, electric fan motors, etc. It can be suitably used as a bearing for parts, auxiliary machines and the like.

It is a fragmentary sectional view of a grease enclosure double row angular bearing. It is a fragmentary sectional view of a single row 4 point contact bearing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inner ring 2 Outer ring 3 Rolling element 4 Cage 5 Contact seal 6 Grease 11 Single row 4 point contact ball bearing 12 Inner ring 13 Outer ring 14 Inner ring rolling surface 15 Outer ring rolling surface 16 Inner ring rolling surface bottom 16a Inner ring rolling surface bottom Center 17 Bottom of outer ring rolling surface 17a Center of outer ring rolling surface bottom 18 Rolling element 19 Grease

Claims (4)

An inner ring having two rows of tracks, an outer ring having tracks corresponding to the tracks of the inner ring, and a plurality of rolling elements arranged in two rows between the inner and outer rings, at least the rolling elements Is a double row angular contact bearing with grease sealed around
The grease comprises a base grease composed of a base oil and a thickener, and the additive contains at least one aluminum-based additive selected from aluminum powder and an aluminum compound. A grease-enclosed double-row angular bearing characterized in that the mixing ratio of the system additive is 0.05 to 10 parts by weight with respect to 100 parts by weight of the base grease.   The grease-enclosed double-row angular bearing according to claim 1, wherein the aluminum compound is at least one compound selected from aluminum carbonate and aluminum nitrate.   The grease-enclosed double-row angular bearing according to claim 1 or 2, wherein the thickener is a urea-based thickener.   The grease-enclosed double row angular bearing according to claim 1, 2 or 3, wherein the base oil is at least one oil selected from alkyl diphenyl ether oil and poly-α-olefin oil. .

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