JP2006029347A - Rolling bearing for automobile electric auxiliary machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rolling bearing, used for automobile electric auxiliary machines, in which an elastic body of a hermetically-sealed plate acting as a sealing member is less deteriorated even under high-speed and high-temperature conditions to make good seal performance held over the long term, thus realizing excellence in reliability and endurance in a bearing in which grease containing a urea compound is encapsulated. <P>SOLUTION: There is provided a rolling bearing, used for automobile electric auxiliary machines such as an electromagnetic clutch, a compressor and an idler pulley. The rolling bearing is equipped with an inner race and an outer race, a plurality of rolling elements intervened between the inner and outer races, grease containing the urea compound encapsulated in a periphery of the rolling elements, and a sealing member provided at openings of both ends in an axial direction of the inner and outer races to encapsulate the grease. The sealing member includes a molded rubber body in contact with at least the grease. The molded rubber body is formed of a fluorocarbon-rubber composite that contains tetrafluoroethylene, propylene and cross-linking monomers consisting of unsaturated hydrocarbon with the number of carbons 2 to 4 created by replacing part of hydrogen atoms with fluorine atoms and can be vulcanized. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a rolling bearing for an automotive electrical accessory, and more particularly to a rolling bearing for an automotive electrical accessory used in an electromagnetic clutch, a compressor, and an idler pulley.

In recent years, along with demands for miniaturization, weight reduction, and quietness improvement of automobiles, electrical accessory parts have been reduced in size, weight, and sealed in the engine room. The demand for higher output and higher efficiency is increasing in itself, and in an electrical accessory in the engine room, a method of compensating for a decrease in output caused by downsizing by rotating at high speed is adopted.
Car air conditioners operate by driving the compressor by transmitting engine power to an electromagnetic clutch by a drive belt and connecting the clutch. Deep groove ball bearings and sealed double row angular contact ball bearings are used as electromagnetic clutch bearings, and needle roller bearings are used as compressor bearings.
The idler pulley is used as a belt tensioner for the drive belt that transmits the engine power to the auxiliary equipment of the automobile, and is used to tension the belt as a tensioner when the distance between the shafts is fixed. The function as a pulley is combined with the function as an idler that is used to change the running direction of the belt or to avoid an obstacle to reduce the volume of the engine compartment. A deep groove ball bearing or the like is used as the idler pulley bearing.
As described above, the electromagnetic clutch, the compressor, and the idler pulley are also required to have a high speed for miniaturization and weight reduction, and to be quiet. Each of the above bearings is required to have heat resistance, grease sealability, and durability that can withstand extremely harsh environments such as high-speed rotation of 10,000 rpm or higher at a high temperature of 180 ° C. or higher.

  Conventionally, urea grease is mainly used for lubrication of the rolling bearing, and fluorine grease is used when the temperature condition is severe. Fluorine grease is very expensive, or the rust preventive agent that can be added is limited. Therefore, a grease using a mixture of fluorine grease and grease other than fluorine grease (see Patent Document 1) is also available. in use.

On the other hand, heat resistance is also required for the seal member for rolling bearings in applications where such temperature conditions are severe. Conventionally, acrylic rubber has been used as the elastic body of the seal member. However, acrylic rubber is not sufficient in heat resistance, and the number of cases using fluororubber is increasing.
Conventionally used fluororubbers include binary copolymers of vinylidene fluoride and hexafluoropropylene (VDF-HFP), and terpolymers of which tetrafluoroethylene is added (VDF-HFP-TFE). So-called FKM is common. When these fluororubbers are used in combination with fluorine grease, sufficient durability can be obtained.
However, a combination of fluororubber and urea-based grease has a problem that the fluororubber is cross-linked by the urea compound and hardens.
On the other hand, by using a terpolymer of vinylidene fluoride-tetrafluoroethylene-propylene or a tetrafluoroethylene-propylene binary copolymer as the fluororubber, a rolling bearing is used in combination with urea grease. There has been proposed a method for improving the durability (see Patent Document 2).

However, even when the above-mentioned fluoro rubber is used, it is difficult to suppress the deterioration of fluoro rubber over time under the high temperature and high speed conditions required for rolling bearings for electromagnetic clutches, compressors, and idler pulleys in recent years. There's a problem.
When the rubber elastic body used for the seal member is cured, the sealing performance is deteriorated, which causes grease leakage and a problem of shortening the bearing life. In addition, the contact pressure at the seal surface is increased, and the rotational torque of the bearing is increased. As a result, frictional heat is generated, and the grease is further deteriorated.
JP 2003-239997 A JP 2001-66578 A

  The present invention has been made to cope with such problems, and in a bearing in which grease containing a urea compound is sealed, the deterioration of the elastic body of the sealing plate, which is a sealing member, is small and excellent even under high speed and high temperature conditions. An object of the present invention is to provide a rolling bearing for automotive electrical equipment that maintains a long sealing performance and is excellent in reliability and durability.

A rolling bearing for automotive electrical accessory according to the present invention is a rolling bearing for automotive electrical accessory that rotatably supports a rotating part provided in the automotive electrical accessory, and the rolling bearing includes an inner ring and an outer ring, A plurality of rolling elements interposed between the inner ring and the outer ring, grease containing a urea compound sealed around the rolling elements, and the axially opposite end openings of the inner ring and the outer ring, and sealing the grease A sealing member that has at least a rubber molded body that contacts the grease, wherein the rubber molded body is substituted with tetrafluoroethylene, propylene, and a part of hydrogen atoms with fluorine atoms. And a molded article of a vulcanizable fluororubber composition comprising a crosslinking monomer composed of an unsaturated hydrocarbon having 2 to 4 carbon atoms.
The automotive electrical accessory is an electromagnetic clutch, a compressor, or an idler pulley.

The crosslinking monomer is trifluoroethylene, 3,3,3-trifluoropropene-1,1,2,3,3,3-pentafluoropropene, 1,1,3,3,3-penta. It is at least one monomer selected from fluoropropylene and 2,3,3,3-tetrafluoropropene.
The fluororubber composition contains vinylidene fluoride.

A rolling bearing for automotive electrical equipment according to the present invention is a crosslinking monomer comprising tetrafluoroethylene, propylene, and an unsaturated hydrocarbon having 2 to 4 carbon atoms in which part of hydrogen atoms is substituted with fluorine atoms. Since the sealing member is formed from a molded body of a vulcanizable fluororubber composition containing, there is little deterioration in physical properties even when immersed in grease containing a urea compound, and leakage of grease can be effectively prevented. .
For this reason, when using the rolling bearing for automotive electrical equipment as a rolling bearing for an electromagnetic clutch, a compressor, and an idler pulley, the usage conditions are a high temperature of 180 ° C. or higher and a high speed rotation of 10,000 rpm or higher. Also, the durability of the bearing can be improved.

An electromagnetic clutch and a compressor using the rolling bearing for automotive electrical accessory of the present invention will be described with reference to FIG. FIG. 3 is a cross-sectional view of the electromagnetic clutch and the scroll compressor.
The operation of the electromagnetic clutch 9 will be described below. The rolling bearing 1 incorporated in the pulley 11 is mounted on the nose portion 17 of the compressor 10 and its outer ring is always rotated by belt driving. When the coil 14 a of the stator 14 is energized, the clutch plate 16 fixed to the compressor rotating shaft 15 is attracted to the pulley 11 by the magnetic flux generated by the coil current and connected to drive the compressor rotating shaft 15.
The electromagnetic clutch has functions such as transmission and interruption of torque between the engine and the compressor by the above operation, procurement of the compressor rotation speed by selection of the pulley diameter, shock reduction during compressor operation, and absorption of torque fluctuation during steady rotation.
The scroll-type compressor 10 includes a movable scroll 12 and a fixed scroll 13 that are a pair of spiral parts, and a structure in which a space formed between both scrolls is reduced in volume while moving from the outside to the center to compress the refrigerant. It has become.
The rotation speed of the compressor rotating shaft 15 is 10000 rpm or more, the maximum is about 12000 rpm, and the ambient temperature may rise to about 180 ° C. Therefore, the rolling bearing 1 of the electromagnetic clutch 9 and other rolling bearings (not shown) in the compressor shown in FIG. 3 need to have sufficient durability even under the use conditions.

An example of an idler pulley used as a belt tensioner for an automobile accessory drive belt is shown in FIG. FIG. 4 is a sectional view of the idler pulley.
This pulley includes a pulley body 18 made of a steel plate press and a single row deep groove ball bearing 1 fitted to the inner diameter of the pulley body 18. The pulley body 18 includes an inner diameter cylindrical portion 18a, a flange portion 18b extending from one end of the inner diameter cylindrical portion 18a to the outer diameter side, an outer diameter cylindrical portion 18c extending in the axial direction from the flange portion 18b, and the other end of the inner diameter cylindrical portion 18a. This is an annulus composed of a flange 18d extending to the inner diameter side. An outer ring 3 of the ball bearing 1 is fitted to the inner diameter of the inner cylindrical portion 18a, and a pulley peripheral surface 18e that contacts a belt driven by the engine is provided on the outer diameter of the outer cylindrical portion 18c. By bringing the pulley peripheral surface 18e into contact with the belt, the pulley functions as an idler. The idler pulley also needs to have the same level of durability as the electromagnetic clutch and the compressor increase in speed.

FIG. 1 shows an example of a rolling bearing for an automotive electrical accessory according to the present invention. FIG. 1 is a cross-sectional view of a deep groove ball bearing filled with grease.
In the deep groove ball bearing 1, an inner ring 2 having an inner ring rolling surface 2a on the outer peripheral surface and an outer ring 3 having an outer ring rolling surface 3a on the inner peripheral surface are arranged concentrically, and the inner ring rolling surface 2a and the outer ring rolling surface 3a. A plurality of rolling elements 4 are arranged between the two. Sealers 6 that are fixed to the cage 5, the outer ring 3, and the like that hold the plurality of rolling elements 4 are provided in the axially opposite end openings 8a, 8b of the inner ring 2 and the outer ring 3, respectively. Grease 7 is sealed at least around the rolling element 4.
As the rolling bearing, it is possible to use a sealed double-row angular ball bearing because it can be made compact, has a small angular runout (angular clearance), and has good assembly workability.

The seal member 6 may be a rubber molded body alone or a composite of a rubber molded body and a metal plate, a plastic plate, a ceramic plate, or the like. From the viewpoint of durability and ease of fixing, a composite of a rubber molded body and a metal plate is preferable.
An example of the sealing member 6 made of a composite of a rubber molded body and a metal plate is shown in FIG. The seal member 6 is obtained by fixing a fluororubber molded body 6b to a metal plate 6a such as a steel plate. As the fixing method, either mechanical fixing or chemical fixing may be used. As a preferable fixing method, there can be mentioned a method in which a metal plate is placed in a vulcanizing mold, and molding and vulcanization are performed and fixed at the time of vulcanization of a fluororubber molded article.

The seal member 6 can be mounted by (1) fixing one end 6c of the seal member 6 to the outer ring 3, and forming the labyrinth gap along the V groove on the seal surface of the inner ring 2 at the other end 6d. One end 6c of the member 6 is fixed to the outer ring 3, and the other end 6d is brought into contact with the V groove side surface of the seal surface of the inner ring 2. (3) One end 6c of the seal member 6 is fixed to the outer ring 3, and the other end 6d is the inner ring. 2 is contacted with the side surface of the V-groove of the sealing surface, but a low-torque structure is provided by providing a suction-preventing slit or the like in the contacting lip portion.
In any of the above mounting methods, the sealed grease 7 comes into contact with the rubber molded body 6b constituting the seal member 6. The rubber molded body 6b is formed of a fluororubber molded body, which will be described later, at least at a portion in contact with the sealed grease 7. For example, the rubber molded body 6b may be a single fluororubber molded body, which will be described later, or a laminated body in which a conventional rubber molded body is laminated on the back surface of the above-described fluororubber molded body at a portion in contact with the grease 7.

The fluororubber composition that can be used in the present invention comprises tetrafluoroethylene, propylene, and a crosslinking monomer comprising an unsaturated hydrocarbon having 2 to 4 carbon atoms in which some of the hydrogen atoms are substituted with fluorine atoms. And a vulcanizable fluororubber composition comprising a copolymer.
Examples of the crosslinking monomer composed of an unsaturated hydrocarbon having 2 to 4 carbon atoms in which a part of hydrogen atoms are substituted with fluorine atoms include trifluoroethylene, 3, 3, 3-trifluoropropene-1, 1, 2, 3, 3, 3-pentafluoropropene, 1, 1, 3, 3, 3-pentafluoropropylene, 2, 3, 3, 3-tetrafluoropropene are mentioned. A preferred crosslinking monomer is 3,3,3-trifluoropropene-1.

  As a fourth component in the copolymer that can be used in the present invention, vinylidene fluoride, chlorotrifluoroethylene, perfluoro (alkyl vinyl) ether, perfluoro (alkoxy vinyl) ether, perfluoro (alkoxyalkyl vinyl) ether, perfluoroalkyl alkenyl ether, A perfluoroalkoxy alkenyl ether etc. can be mix | blended.

The components constituting the fluororubber composition are 45 to 80% by weight, preferably 50 to 78% by weight, more preferably 65 to 78% by weight, and 10 to 10% propylene with respect to the whole fluororubber. 40% by weight, preferably 12-30% by weight, more preferably 15-25% by weight, and 0.1-15% by weight of crosslinking monomer, preferably 2-10% by weight, more preferably 3-6% by weight %.
When vinylidene fluoride is copolymerized, the vinylidene fluoride content is 2 to 20% by weight, preferably 10 to 20% by weight. If it exceeds 20% by weight, the resistance to urea compounds decreases.

This fluororubber production method is disclosed in, for example, International Publication No. WO02 / 092683, and is produced by an emulsion polymerization method or a suspension polymerization method.
In order to vulcanize these fluororubbers, vulcanization accelerators selected from polyhydroxy (polyol) vulcanizing agents, quaternary ammonium salts, fourth phosphonium salts, third sulfonium salts, etc., calcium hydroxide and magnesium oxide Etc., fillers such as carbon black, clay, barium sulfate, calcium carbonate and magnesium silicate, processing aids such as octadecylamine and wax, heat aging inhibitors and pigments can be blended. For example, each compounding amount is 0.1 to 20 parts by weight, preferably 0.5 to 3 parts by weight, and 0.1 to 20 parts by weight, preferably 0.5 to 3 parts by weight, of the vulcanizing agent, based on 100 parts by weight of fluororubber. 1 to 30 parts by weight, preferably 1 to 7 parts by weight, 5 to 100 parts by weight of filler, and 0.1 to 20 parts by weight of processing aid.

In addition to these, a second vulcanizing agent such as an organic peroxide compound may be added in an amount of 0.7 to 7 parts by weight, preferably 1 to 3 parts by weight. Furthermore, fillers and additives that can be blended in general rubber compositions can be used as appropriate within a range that does not impair the resistance to urea compounds and the sealing properties.
As a method for mixing or molding these compositions, a process used for general rubber processing can be adopted. After kneading with an open roll, a Banbury mixer, a kneader, various sealed mixers, etc., press molding (press vulcanization) ), Extrusion molding, injection molding, etc. In order to improve the properties, secondary vulcanization is preferably performed after molding, and this is performed by sufficiently heating in an oven (for example, 200 ° C. for 24 hours).

The rolling bearing contains a urea grease containing a urea compound.
Base oils for urea grease include mineral oils such as paraffinic mineral oil and naphthenic mineral oil, synthetic hydrocarbon oils such as poly-α-olefin oil (PAO), dialkyl diphenyl ether oil, alkyl triphenyl ether oil, alkyl tetra Ether oils such as phenyl ether oils, diester oils, polyol ester oils, or ester oils such as complex ester oils, aromatic ester oils, carbonate ester oils, and the like can be used alone or mixed with each other.
Among these, alkyl diphenyl ether oil, ester oil, poly-α-olefin oil (PAO) and the like are preferable in consideration of lubrication performance at high temperature and high speed and lubrication life.

また、Ｒ₁およびＲ₃は、１価の脂肪族基、脂環族基または芳香族基をそれぞれ表す。特に、Ｒ₁およびＲ₃が脂肪族基である脂肪族ジウレアを増ちょう剤とするウレア系グリースがフッ素グリースとの混合には容易に混合するので好ましい。なお、ウレア化合物の製造方法の一例としては、ジイソシアナート化合物にイソシアナート基当量のアミン化合物を反応させて得られる。 The urea compound blended as a thickener contains a urea bond (—NHCONH—) in the molecule, and examples include diurea, triurea, tetraurea, urea urethane, and the like. A preferred urea compound is diurea having two urea bonds in the molecule, and is represented by the following chemical formula 1. R ₂ is a divalent aromatic hydrocarbon group having 6 to 15 carbon atoms, and is specifically represented by the following chemical formula 2.

R ₁ and R ₃ each represent a monovalent aliphatic group, alicyclic group or aromatic group. In particular, a urea-based grease using an aliphatic diurea in which R ₁ and R ₃ are aliphatic groups as a thickener is preferable because it is easily mixed with a fluorine grease. In addition, as an example of the manufacturing method of a urea compound, it is obtained by making an isocyanate compound equivalent to an isocyanate group react with a diisocyanate compound.

  The urea grease is preferably blended in an amount of 95 to 70% by weight of the base oil and 5 to 30% by weight of the urea compound based on the total amount of the grease. By blending in this range, the grease contained in the bearing can be adjusted to a consistency with good lubricity for a long time with less grease leakage.

When the operating temperature conditions are severe, fluorine grease can be used in combination with grease containing the above urea compound as a thickener.
A preferred example of the fluorine grease is polytetrafluoroethylene (PTFE) as a thickener and perfluoropolyether (PFPE) as a base oil.
The fluorine grease is preferably blended in an amount of 50 to 90% by weight of perfluoropolyether oil and 50 to 10% by weight of fluororesin particles based on the total amount of the grease. By blending in this range, it is possible to adjust to a preferred consistency that can reduce the torque for a long time with less leakage as the grease contained in the bearing.

  The mixing ratio (weight ratio) of urea grease and fluorine grease is preferably in the range of 30:70 to 75:25 for urea grease: fluorine grease. The most preferred components of the urea grease in combination with the fluorine grease are those in which the thickener is an aliphatic diurea, the base oil is an ester oil, the fluorine grease is a thickener PTFE, and the base oil is PFPE.

Urea-based greases and mixed greases used in the production of examples of rolling bearings for automotive electrical accessories of the present invention, comparative examples, and seal member examples of the bearings are shown below.
(1) Urea grease 1
Made by Crububa: Asonic HQ72-102 (Thickener: aliphatic diurea, base oil: aromatic polyester oil, kinematic viscosity at 40 ° C. 100 mm ² / s)
(2) Urea grease 2
A base oil composed of a mixed oil of poly-α-olefin oil (trade name, Shinflud 601 manufactured by Nippon Steel Chemical Co., Ltd.) and alkyl diphenyl ether oil (trade name, manufactured by Matsumura Oil Co., Ltd., LB100) is prepared at a blending ratio of 20: 80% by weight. did. This base oil is divided into two liquids, and 4,4′-diphenylmethane diisocyanate is dissolved in half of the base oil, and the remaining half of the base oil has a double equivalent of 4,4′-diphenylmethane diisocyanate. Toluidine was dissolved. In addition, 4,4′-diphenylmethane diisocyanate was dissolved so as to be 20% by weight of the total amount of the grease composition as an aromatic diurea compound. After adding the p-toluidine solution while stirring the solution, stirring was continued for 30 minutes at 100 to 120 ° C. to cause the aromatic diurea compound to precipitate in the base oil. To this, 100 parts by weight of the total amount of grease was added 1 part by weight of sorbitan trioleate, 1 part by weight of sodium sebacate and 2 parts by weight of alkyldiphenylamine as an antioxidant, 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 composition.
(3) Mixed grease The total weight of the grease is 33% by weight of fluororesin powder (DuPont product name, Vidax) and 67% by weight of perfluoropolyether oil (DuPont product name, Krytox 240AC). After stirring, the mixture was passed through a roll mill to obtain a semi-solid fluorine grease which was “a grease using PTFE powder as a thickener and PFPE as a base oil”.
Next, with respect to the entire grease, aromatic ester oil (trade name, Asahi Denka Kogyo Co., Ltd., Prover T90) dissolves 1 mol of diisocyanate in half of 88% by weight, and dissolves 2 mol of monoamine in the remaining half of the above half amount. And then stirred for 30 minutes at 100 to 120 ° C. to react with a urea compound (a fatty acid in which R ₁ and R ₃ are aliphatic groups and R ₂ is a diphenylmethane group) Group diurea) was precipitated in the base oil. Thereafter, it was passed through a roll mill to obtain a semi-solid urea grease which was “a grease using a urea compound as a thickener and a synthetic oil as a base oil”.
40 wt% of the above fluorine grease, 59 wt% of urea grease, and 1 wt% of amine-based antirust additive based on mineral oil were mixed and stirred to obtain a mixed grease of fluorine grease and urea grease.

The rubber compositions used in the respective sealing member examples, examples, and comparative examples are shown below.
An unvulcanized rubber composition was obtained by kneading using an open roll at a roll temperature of 50 ° C. with the composition shown in Table 1. Each material used in Table 1 is shown below.
(1) Fluoro rubber 1: manufactured by DuPont Dow Elastomer Co., Ltd .; VTR8802 (with vulcanizing agent)
(2) Fluoro rubber 2: manufactured by Asahi Glass; Afras 150
(3) Fluoro rubber 3: manufactured by DuPont Dow Elastomer; A32J
(4) Acrylic rubber: Nippon Zeon Corporation; AR71
(5) Magnesium oxide: manufactured by Kyowa Chemical Industry Co., Ltd .;
(6) Calcium hydroxide: manufactured by Omi Chemical Industry Co., Ltd .; Calbit (7) Carbon 1: manufactured by Engineered Company; N990
(8) Co-crosslinking agent: Nippon Kasei Co., Ltd .; TAIC
(9) Vulcanizing agent: manufactured by Kayaku Akzo; Parkadox 14
(10) Carbon 2: Tokai Carbon Co., Ltd .; Seast 3
(11) Sulfur: manufactured by Tsurumi Chemical Co., Ltd .; Sulfax PMC
(12) Anti-aging agent: Ouchi Shinsei Chemical Co., Ltd .; NOCRACK CD
(13) Sodium stearate: manufactured by Kao Corporation; NS soap (14) potassium stearate: manufactured by NOF Corporation; Non-Sal SK-1

シール部材例１〜シール部材例５は、高温条件下、長時間の浸漬でも劣化が軽微であり、ウレア系グリースおよび混合グリースに対して優れた耐性を有していた。 Seal member example 1 to seal member example 5, comparative seal member example 1 to comparative seal member example 9
Using the unvulcanized rubber composition, a vulcanized molded product was obtained with a vulcanizing press. The actual temperature of the mold was 170 ° C, and the vulcanization time was vulcanized at 170 ° C for 12 minutes as the primary vulcanization. Subsequently, secondary vulcanization was performed in a thermostatic bath. Secondary vulcanization conditions are as follows: Formulation Examples 1 to 3 are 200 ° C. for 24 hours, and Formulation Example 4 is 170 ° C. for 4 hours.
The obtained vulcanized molded product was punched into the shape of a JIS K 6251 No. 3 test piece to prepare a test piece. The test piece was embedded and immersed in the urea grease 1, urea grease 2 and the mixed grease (170 ° C. or 200 ° C.) × 1000 hours, and the physical properties before and after immersion were measured. The measured physical properties were measured for hardness, tensile strength, tensile elongation, and volume, and evaluated for hardness change, tensile strength change rate, tensile elongation change rate, and volume change rate with respect to the physical property values before immersion. The measurement conditions were based on JIS K 6251K, JIS K 6253K, and JIS K 6258. The results are shown in Tables 2-4. In Tables 3 and 4, * indicates that measurement is impossible.

Seal member example 1 to seal member example 5 had a slight deterioration even when immersed for a long time under high temperature conditions, and had excellent resistance to urea grease and mixed grease.

Example 1
The unvulcanized rubber composition of Formulation Example 1 was molded into a steel core and a non-contact rubber seal (Fig. 2) for 6204 bearing (inner diameter: 20 mm, outer diameter: 47 mm, width: 14 mm) was obtained. It was. This was incorporated into a bearing thoroughly cleaned with petroleum benzine, and a mixed grease of 38% of the total space volume was sealed inside the bearing to produce a rolling bearing for a test automobile electrical accessory. The obtained rolling bearing was evaluated in the high temperature durability test 1. The results are shown in Table 5.
In the high temperature durability test 1, the bearing was rotated at a radial load of 67 N, a thrust load of 67 N, a rotation speed of 10000 rpm, and an ambient temperature of 220 ° C., and the time until the motor stopped due to overload was measured. The maximum test time was 1000 hours.

Example 2
Rolling bearings for automotive electrical accessories for testing by incorporating the same non-contact type rubber seal as in Example 1 into bearings thoroughly cleaned with petroleum benzine and enclosing 38% urea grease 2 in the interior of the bearings. Was made. The obtained rolling bearing was evaluated in the high temperature durability test 2 described above. The results are shown in Table 5.
In the high temperature durability test 2, the bearing was rotated at a radial load of 67 N, a thrust load of 67 N, a rotation speed of 10000 rpm, and an ambient temperature of 180 ° C., and the time until the motor stopped due to overload was measured. The maximum test time was 500 hours.

Comparative Example 1 and Comparative Example 2
Using the blending example 2 and the blending example 3, the rolling bearings for automotive electrical equipment for testing of the comparative example 1 and the comparative example 2 were produced in the same manner as in the first example. A high-temperature durability test 1 similar to that of Example 1 was performed, and the results are shown in Table 5.

実施例１および実施例２では 500 時間以上の運転が可能であり、試験後のシールも目視でクラックはみられなかった。
一方、比較例１および比較例２は実施例１に比べて、比較例３および比較例４は実施例２に比べて短時間で焼きつきが生じた。運転中のグリースの漏洩が短寿命の主な原因と思われる。なお、比較例２および比較例４の試験後のシールの接触部には多数のクラックがみられた。 Comparative Example 3 and Comparative Example 4
Using the blending example 2 and the blending example 3, the rolling bearings for automobile electrical accessory for testing of the comparative example 3 and the comparative example 4 were produced in the same manner as in the example 2. A high-temperature durability test 2 similar to that of Example 2 was performed, and the results are shown in Table 5.

In Example 1 and Example 2, operation for 500 hours or more was possible, and no cracks were visually observed in the seal after the test.
On the other hand, in Comparative Example 1 and Comparative Example 2, image sticking occurred in a shorter time than in Example 1, and in Comparative Example 3 and Comparative Example 4 compared with Example 2. Leakage of grease during operation seems to be the main cause of short life. In addition, many cracks were seen in the contact part of the seal | sticker after the test of the comparative example 2 and the comparative example 4. FIG.

  Since the rolling bearing of the present invention has excellent urea grease resistance, it can be suitably used as a rolling bearing for automobile electrical accessories used at high speeds and high temperatures, particularly for electromagnetic clutches, compressors, and idler pulleys.

It is sectional drawing of the rolling bearing of this invention. It is sectional drawing of the sealing member of a rolling bearing. It is sectional drawing of an electromagnetic clutch and a compressor. It is sectional drawing of an idler pulley.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Deep groove ball bearing 2 Inner ring 3 Outer ring 4 Rolling body 5 Cage 6 Seal member 7 Grease 8 Opening 9 Electromagnetic clutch 10 Compressor 11 Pulley 12 Movable scroll 13 Fixed scroll 14 Stator 15 Compressor rotating shaft 16 Clutch plate 17 Nose part 18 Pulley body

Claims (5)

A rolling bearing for an automotive electrical accessory that rotatably supports a rotating part provided in the automotive electrical accessory,
The rolling bearing includes an inner ring and an outer ring, a plurality of rolling elements interposed between the inner ring and the outer ring, grease containing a urea compound sealed around the rolling elements, and axially open ends of the inner ring and the outer ring. Provided with a sealing member for sealing the grease,
The seal member has a rubber molded body that comes into contact with at least the grease, and the rubber molded body is tetrafluoroethylene, propylene, and a non-carbon group having 2 to 4 carbon atoms in which some hydrogen atoms are substituted with fluorine atoms. A rolling bearing for automotive electrical equipment, characterized by being a molded body of a vulcanizable fluororubber composition containing a crosslinking monomer comprising a saturated hydrocarbon.   The rolling bearing for an automotive electrical accessory according to claim 1, wherein the automotive electrical accessory is an electromagnetic clutch, a compressor, or an idler pulley.   The crosslinking monomer is trifluoroethylene, 3,3,3-trifluoropropene-1,1,2,3,3,3-pentafluoropropene, 1,1,3,3,3-pentafluoropropylene The rolling bearing for automotive electrical equipment according to claim 1 or 2, wherein the rolling bearing is at least one monomer selected from 2,3,3,3-tetrafluoropropene.   The rolling bearing for automotive electrical equipment according to claim 1, wherein the fluororubber composition contains vinylidene fluoride.   The rolling bearing for an automotive electrical accessory according to any one of claims 1 to 4, wherein the grease containing the urea compound is a mixed grease of fluorine grease and urea grease.

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