JP6309767B2 - Rolling bearings for automotive electrical equipment and accessories - Google Patents

Description

  The present invention relates to a rolling bearing used for an electrical component of an automobile such as an alternator, an electromagnetic clutch for a car air conditioner, a fan coupling device, an intermediate pulley, and an electric fan motor, and an auxiliary machine.

  In recent years, along with demands for miniaturization, weight reduction, and improvement in quietness of automobiles, miniaturization, weight reduction, and sealing of engine compartments have been attempted for electrical components and auxiliary equipment parts. On the other hand, there is an increasing demand for high output and high efficiency in the performance of the equipment itself. In the electrical equipment and auxiliary equipment in the engine room, a method of compensating for the decrease in output caused by downsizing by rotating at high speed. Has been adopted. Hereinafter, outlines of a rolling bearing for a fan coupling device, a rolling bearing for an alternator for an automobile, and a rolling bearing for an idler pulley will be described as examples of the rolling bearing for an electric vehicle / auxiliary machine.

  A fan coupling device for automobiles has a housing in which viscous fluid is sealed inside and a fan for blowing air on the outer peripheral surface is connected to a rotor directly connected to the engine via a bearing, and increases or decreases in response to the ambient temperature. It is a device that performs optimum ventilation corresponding to the engine temperature by controlling the amount of drive torque transmitted from the engine and the rotational speed of the fan using the shearing resistance of the viscous fluid. For this reason, the rolling bearing for the fan coupling device has a rotational speed of 10000 rpm or more at a high temperature of 180 ° C. or higher during high-speed operation in summer, in addition to uneven rotation where the rotational speed fluctuates from 1000 rpm to 10,000 rpm as the engine temperature varies. Durability that can withstand the extremely harsh environment of high-speed rotation is required.

  The alternator for automobiles has a function of generating power by receiving rotation of an engine with a belt, supplying electric power to an electric load of the vehicle, and charging a battery. The idler pulley for automobiles is used as a belt tensioner for a drive belt that transmits engine rotation to the auxiliary equipment of the automobile, and gives tension to the belt when the center distance is fixed. The function as a pulley for this purpose is combined with the function as an idler for reducing the volume of the engine compartment by changing the running direction of the belt or avoiding an obstacle. An automobile alternator and an automobile idler pulley are also required to have durability that can withstand extremely harsh environments such as high-speed rotation at a rotational speed of 10,000 rpm or higher at a high temperature of 180 ° C. or higher.

  Grease is mainly used for lubrication of these automotive electrical equipment and auxiliary machinery rolling bearings. However, due to severe conditions of use such as rapid acceleration / deceleration, high temperature, and high speed rotation, there is a possibility that specific peeling accompanied with a change in white structure may occur at an early stage on the rolling surface of the rolling bearing. This specific exfoliation is a destructive phenomenon that occurs from a relatively shallow part of the surface of the rolling surface, unlike the internal peeling caused by normal metal fatigue. It is considered brittle. For example, it is considered that the grease is decomposed to generate hydrogen, which penetrates into the steel of the rolling bearing, thereby causing early peeling due to hydrogen embrittlement.

  Since hydrogen significantly reduces the fatigue strength of steel, cracks are generated and propagated in the inner part of the rolling surface layer where the alternating shear stress is maximized even under conditions considered to be elastohydrodynamic lubrication where the contact elements are separated by an oil film. It leads to peeling. Also, when used under conditions where water mixes with grease, causes slipping, or energizes, water or grease decomposes and hydrogen tends to be generated, which penetrates into steel. Thus, it is considered that the above-described early peeling due to hydrogen embrittlement is likely to occur.

  As a method for suppressing such a specific peeling phenomenon accompanied with a white tissue change that occurs at an early stage, for example, a method of adding a passivating agent to grease (see Patent Document 1) or a method of adding bismuth dithiocarbamate (See Patent Document 2). In addition, since the bearing rolling surface is made of ferrous metal bearing steel, considering the mutual solubility with iron, the grease composition contains metal powders such as aluminum, silicon, titanium, tungsten, molybdenum, chromium and cobalt. A method of blending is also proposed (see Patent Document 3).

  Conventionally, a grease composition used for a rolling bearing is known in which an alkanolamine derivative modified with a hydrophilic group is blended as a hydrophilic organic inhibitor (see Patent Document 4). This alkanolamine derivative is a salt of an acid such as dibasic acid such as dodecanoic acid or sebacic acid or boric acid and an alkanolamine such as diethanolamine, aminotetrazole or diethylaminoethanol.

  In addition, as a lubricant composition with excellent heat resistance, mechanical stability, water resistance, rust resistance, load resistance, flame resistance, etc., base oil made of mineral oil or synthetic oil, tribasic calcium phosphate and diethanolamine The thing which mix | blended grease structure stabilizers, such as a kind, is proposed (refer patent document 5).

JP-A-3-210394 JP-A-2005-42102 JP 2008-266424 A JP-A-11-279578 JP 2008-156624 A

  However, in recent automobile electrical components and accessories, the contact surface pressure applied to the bearing member tends to increase with downsizing, and the frequency of sudden acceleration / deceleration increases with advanced functions such as idling stop. It tends to increase. An increase in the surface pressure between the rolling elements and the raceway or an increase in slip due to sudden acceleration / deceleration easily causes oil film breakage (poor lubrication) at the portion. Under such a severe environment, the method of adding a passivating agent or bismuth dithiocarbamate as in conventional Patent Document 1 and Patent Document 2 is insufficient as a measure for preventing the above-described peeling phenomenon. ing.

  As the oil film thickness on the bearing sliding surface becomes thinner, the peeling phenomenon is more likely to occur. In particular, in the above-mentioned severe environment, the lubrication of the sliding surface becomes the boundary lubrication condition, and the oil film thickness is on the order of submicron (0.1 μm or less). Under such circumstances, for example, as in Patent Document 3, even when a metal powder having a certain mutual solubility with iron is used, depending on the particle diameter, the sliding surface cannot be sufficiently intervened, and the effect is effective. May not be obtained.

  As in Patent Document 4, some conventional grease compositions for rolling bearings contain an alkanolamine salt, but the ability to prevent the above-described peeling phenomenon with an alkanolamine alone has not been studied. In addition, the grease composition described in Patent Document 5 has not been studied for its ability to prevent the peeling phenomenon, and may have an adverse effect depending on the specific combination of essential components. In addition, since the rolling element bearings for automobile electrical components and auxiliary machines are used under high temperature conditions as described above, it is necessary to prevent the above-mentioned peeling phenomenon and maintain excellent high temperature durability.

  The present invention has been made to cope with such a problem, and can prevent peeling on the rolling surface due to hydrogen embrittlement under the use conditions of a rolling bearing used in automobile electrical equipment and auxiliary equipment, and at a high temperature. The purpose is to provide rolling bearings for automotive electrical equipment and accessories that have excellent durability.

  The rolling bearing for automobile electrical equipment / auxiliary machinery according to the present invention is a bearing that rotatably supports a rotating shaft that is driven to rotate by engine output on a stationary member. The rolling bearing includes an inner ring and an outer ring, and the inner ring and the outer ring. A plurality of rolling elements interposed therebetween, a seal member that covers openings in the axial direction of the inner ring and the outer ring, and a grease composition that is sealed around the rolling elements. Oil, a thickener, and an alkanolamine, no alkali metal salt or alkaline earth metal salt of an inorganic acid, and the base oil comprises (A) an alkyldiphenyl ether oil as an essential component with respect to the whole base oil. And an oil containing 25% by weight or more based on the total base oil as an essential component.

  The alkanolamine is a dialkanolamine or a trialkanolamine. In particular, it is characterized by being diethanolamine.

  The thickener is an alicyclic diurea compound. Further, the alkanolamine is contained in an amount of 0.1 to 10% by weight based on the entire grease composition.

  The rolling bearing for automobile electrical equipment / auxiliary machine according to the present invention is a bearing that rotatably supports a rotating shaft, which is driven to rotate by engine output, on a stationary member, and includes a plurality of rolling rings interposed between an inner ring and an outer ring, and an inner ring and an outer ring. A moving body, a seal member that covers openings in both axial ends of the inner ring and the outer ring, and a grease composition sealed around the rolling element, the grease composition comprising a base oil, a thickener, and an alkanol An amine, an alkali metal salt of an inorganic acid and an alkaline earth metal salt, and a base oil containing (A) an alkyldiphenyl ether oil as an essential component and 25% by weight or more based on the total base oil, or (B) Since it is an oil containing 25% by weight or more of the base oil as an essential component with respect to the whole base oil, even under the use conditions of rolling bearings used in recent automobile electrical equipment and auxiliary equipment, It prevents delamination at the rolling run surface, and is excellent in high-temperature durability. For this reason, it can be suitably used as a rolling bearing having an excellent bearing life in automotive electrical parts and accessories such as alternators, electromagnetic clutches for car air conditioners, fan coupling devices, intermediate pulleys, and electric fan motors.

It is sectional drawing of the deep groove ball bearing which shows one Example of the rolling bearing for motor vehicle electrical equipment and auxiliary machines of this invention. It is sectional drawing which shows the fan coupling apparatus using the rolling bearing for motor vehicle electrical equipment and auxiliary machines of this invention. It is sectional drawing which shows the alternator using the rolling bearing for motor vehicle electrical equipment and auxiliary machines of this invention. It is sectional drawing which shows the idler pulley using the rolling bearing for motor vehicle electrical equipment and auxiliary machines of this invention. It is a figure which shows the acid value measurement result of a base oil.

  As a result of intensive investigations on grease used for lubrication in order to prevent separation on the rolling surface due to hydrogen embrittlement in rolling bearings for automotive electrical equipment and auxiliaries, alkanolamine is indispensably added to grease using the specified base oil It has been found that by blending as an agent, peeling at the rolling surface due to hydrogen embrittlement can be effectively prevented while having high high temperature durability.

  In rolling bearings, when the rolling elements and raceway rings, or rolling elements and cages make rolling contact / sliding while in contact with lubricating oil or grease, the contact surfaces between the iron based metallic members (main On the rolling surface), there is a case where the oil film is almost lost and the boundary lubrication condition is such that the surfaces of the metals are in direct contact with each other. In recent years, as described above, rolling bearings for automobile electrical equipment / auxiliary machinery are likely to cause an oil film breakage due to an increase in surface pressure between the rolling elements and the raceway and an increase in slip due to sudden acceleration / deceleration. In this way, even when the oil film becomes thin under severe conditions (boundary lubrication conditions) on the rolling surface, the alkanolamine is adsorbed on the frictional wear surface or the new ferrous metal surface exposed by wear, Direct contact between the new ferrous metal surface and grease can be prevented. Thus, it is considered that generation of hydrogen due to the decomposition of grease can be suppressed, unique peeling due to hydrogen embrittlement can be prevented, and the life of the rolling bearing can be extended. The present invention is based on these findings.

  A grease composition used for a rolling bearing for automobile electrical equipment / auxiliary machinery according to the present invention includes a base oil, a thickener, and an alkanolamine as an additive, an alkali metal salt of an inorganic acid, and an alkaline earth of an inorganic acid. Contains no metal salt. Here, examples of the inorganic acid include phosphoric acid (orthophosphoric acid), hydrochloric acid, nitric acid, sulfuric acid, and boric acid. Examples of the alkali metal and alkaline earth metal include lithium, sodium, potassium, calcium, strontium, and barium. Is mentioned. Specific examples include tricalcium phosphate (calcium salt of orthophosphoric acid).

  Examples of the alkanolamine used in the grease composition include primary alkanolamines such as monoisopropanolamine, monoethanolamine, and mono-n-propanolamine, secondary alkanolamines such as N-alkylmonoethanolamine, and N-alkylmonopropanolamine. Examples include tertiary alkanolamines such as alkanolamines, triethanolamine, cyclohexyldiethanolamine, tri (n-propanol) amine, triisopropanolamine, N, N-dialkylethanolamine, and N-alkyl (or alkenyl) diethanolamine. Moreover, it is classified into monoalkanolamine, dialkanolamine, and trialkanolamine according to the number of alkanol groups. In the present invention, iron ions are sandwiched by chelating action of a plurality of hydroxyl groups (alkanol groups) and amino groups, and iron It is preferable to use dialkanolamine or trialkanolamine because it is easy to prevent exposure of the new metal surface.

  Among these, it is preferable to use N-alkyl (or alkenyl) diethanolamine of the following formula (1) because it is excellent in compatibility with the base oil and the ability to prevent the peeling phenomenon, and is also highly available.

R ₁ in the formula represents a linear or branched alkyl group or alkenyl group having 1 to 20 carbon atoms. Moreover, 1-12 are preferable and, as for carbon atom number, 1-8 are more preferable. Specific examples of the compound include N-methyldiethanolamine, N-ethyldiethanolamine, N-propyldiethanolamine, N-butyldiethanolamine, N-pentyldiethanolamine, N-hexyldiethanolamine, N-heptyldiethanolamine, N-octyldiethanolamine, N -Nonyldiethanolamine, N-decyldiethanolamine, N-undecyldiethanolamine, N-lauryldiethanolamine, N-tridecyldiethanolamine, N-myristyldiethanolamine, N-pentadecyldiethanolamine, N-palmityldiethanolamine, N-heptadecyldiethanolamine, N -Oleyl diethanolamine, N-stearyl diethanolamine, N-isostearyl Ethanolamine, N- nonadecyl diethanolamine, N- such eicosyl diethanolamine.

Alkanolamines may be used alone or in combination of two or more. The alkanolamine is preferably liquid or pasty at room temperature and operating temperature. Further, it may be dispersed in a solvent or the like. By using such an alkanolamine, even if the oil film on the rolling contact surface becomes thin under severe conditions in automobile electrical equipment / auxiliary equipment, the alkanolamine easily enters the portion. The kinematic viscosity of the alkanolamine, preferably 10 to 100 mm ² / s at 40 ° C., and more preferably 40~70mm ² / s at 40 ° C..

  Examples of commercially available products of alkanolamine (tertiary diethanolamine) include ADEKA COLUMB FM-812 and ADEKA COLUMB FM-832 manufactured by ADEKA.

  The blending ratio of alkanolamine in the grease composition is preferably 0.1 to 10% by weight with respect to the whole grease. Within this range, specific peeling due to hydrogen embrittlement can be prevented without other adverse effects. If it exceeds 10% by weight, the reactivity with iron becomes too high, and corrosion wear may occur. Preferably it is 0.3 to 10 weight%, More preferably, it is 0.3 to 5 weight%, More preferably, it is 2 to 5 weight%.

  The base oil of the grease composition is (A) an oil containing 25% by weight or more of the alkyldiphenyl ether oil as an essential component and 25% by weight or more based on the whole base oil, or (B) 25% of the whole base oil containing an ester oil as an essential component. Oil containing more than wt%. The base oil which consists only of alkyl diphenyl ether oil, or the base oil which consists only of ester oil may be sufficient. As shown in FIG. 5, the alkyl diphenyl ether oil has excellent acid value stability and excellent high-temperature durability. In addition, even when a base oil containing an ester oil is used, by using the base oil and an alkanolamine in combination, the acid value can be reduced, and the rolling has sufficient high-temperature durability for use in automobile electrical equipment and auxiliary equipment. It becomes a bearing.

  Examples of the alkyl diphenyl ether oil include monoalkyl diphenyl ether oil represented by the following formula (2), dialkyl diphenyl ether oil represented by the following formula (3), and polyalkyl diphenyl ether.

R ₂ , R ₃ , and R ₄ in the formula are each an alkyl group having 8 to 20 carbon atoms, and are bonded to one phenyl ring or bonded to two phenyl rings. Of these, dialkyl diphenyl ether oils having R ₃ and R ₄ are preferred in view of heat resistance and the like.

  Examples of ester oils include dibutyl sebacate, di-2-ethylhexyl sebacate, dioctyl adipate, diisodecyl adipate, ditridecyl adipate, ditridecyl glutarate, and methyl acetyl cinnolate, trioctyl trimellitate, tridecyl Aromatic ester oils such as trimellitate, tetraoctyl pyromellitate, polyol ester oils such as trimethylolpropane caprylate, trimethylolpropane verargonate, pentaerythritol-2-ethylhexanoate, pentaerythritol verargonate, Examples thereof include carbonate ester oil and phosphate ester oil.

  As long as the base oil satisfies the above (A) and (B), other oils such as poly-α-olefin oil (hereinafter also referred to as “PAO”) and mineral oil are used in addition to the alkyldiphenyl ether oil and the ester oil. May be included. In particular, a mixed oil containing PAO oil in the above (A) or (B) is preferable. PAO (synthetic hydrocarbon oil) is a mixture of oligomers or polymers of α-olefins or isomerized α-olefins. Specific examples of the α-olefin include 1-octene, 1-nonene, 1-decene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1 -Nonadecene, 1-eicosene, 1-docosene, 1-tetradocosene, etc. are mentioned, Usually, these mixtures are used.

The kinematic viscosity of the base oil (in the case of a mixed oil, the kinematic viscosity of the mixed oil) is preferably 10 to ²⁰⁰ mm ² / s at 40 ° C. More preferably, it is 10-100 mm < ² > / s, More preferably, it is 30-100 mm < ² > / s.

  The thickener of the above-mentioned grease composition is not particularly limited, and general ones usually used in the field of grease can be used. For example, soap-type thickeners such as metal soaps and composite metal soaps, and non-soap-type thickeners such as benton, silica gel, urea compounds and urea / urethane compounds can be used. Examples of the metal soap include sodium soap, calcium soap, aluminum soap, and lithium soap. Examples of the urea compound and urea / urethane compound include diurea compounds, triurea compounds, tetraurea compounds, other polyurea compounds, and diurethane compounds. Among these, it is preferable to use a urea compound that is excellent in heat resistance and durability and has excellent intervention and adhesion to the rolling surface.

  A urea compound is obtained by reacting a polyisocyanate component and a monoamine component. Examples of the polyisocyanate component include phenylene diisocyanate, tolylene diisocyanate, diphenyl diisocyanate, diphenylmethane diisocyanate, octadecane diisocyanate, decane diisocyanate, and hexane diisocyanate. Moreover, an aliphatic monoamine, an alicyclic monoamine, and an aromatic monoamine can be used for a monoamine component. Aliphatic monoamines include hexylamine, octylamine, dodecylamine, hexadecylamine, octadecylamine, stearylamine, oleylamine and the like. Examples of the alicyclic monoamine include cyclohexylamine. Aromatic monoamines include aniline, p-toluidine and the like.

  Among these urea compounds, since they are particularly excellent in heat resistance durability, diurea compounds using aromatic diisocyanates as polyisocyanate components, for example, aromatic diurea compounds using aromatic monoamines as monoamine components, aliphatic monoamines are used. It is preferable to use an aliphatic diurea compound or an alicyclic diurea compound using an alicyclic monoamine. In particular, it is preferable to use an alicyclic diurea compound because it is excellent in oil supply property even in the use of rotating outer rings such as pulleys.

  Base grease can be obtained by blending a base oil with a thickener such as a urea compound. A base grease using a urea compound as a thickener is prepared by reacting the polyisocyanate component and the monoamine component in a base oil. The blending ratio of the thickener in the base grease is 1 to 40% by weight, preferably 3 to 25% by weight. If the content of the thickener is less than 1% by weight, the thickening effect is reduced, making it difficult to make a grease. If the content exceeds 40% by weight, the obtained base grease becomes too hard and the desired effect is difficult to obtain. Become.

  As a method for preparing the above grease composition, first, alkanolamine is blended in the base oil, and a thickener is prepared using this base oil. Any method of adding liquid may be used. Since the alkanolamine contains an amino group, when a urea compound is used as a thickener, it is possible to add the alkanolamine after preparing the base grease by reacting the polyisocyanate component and the monoamine component in the base oil. This is the preferred method.

  It is preferable that the penetration degree (JIS K 2220) of the grease composition is in the range of 200 to 350. When the consistency is less than 200, oil separation is small and there is a risk of poor lubrication. On the other hand, if the consistency exceeds 350, the grease is soft and easily flows out of the bearing, which is not preferable.

  In the grease composition used for the rolling bearing for automobile electrical equipment / auxiliary machinery according to the present invention, alkanolamine is not present in the form of a reaction product like a salt with an acid but is present as it is. Therefore, as other additives, an additive which forms a salt with an alkanolamine such as a fatty acid is not included. The grease composition may contain a known additive as necessary within the range not impairing the object of the present invention. Examples of 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 thereof include solid lubricants, metal sulfonates, rust inhibitors such as polyhydric alcohol esters, oil agents such as esters and alcohols, and other antiwear agents. These can be added alone or in combination of two or more. Further, in the present invention, even when an organic molybdenum compound such as molybdenum dithiophosphate and molybdenum dithiocarbamate is not blended, peeling at the rolling surface due to hydrogen embrittlement can be prevented.

  Among the above, it is preferable to include at least one antioxidant selected from a phenol-based antioxidant, an amine-based antioxidant, and zinc dithiophosphate. Among these, zinc dithiophosphate is essential, and it is preferable to use one of a phenolic antioxidant and an amine antioxidant in combination. In particular, it is preferable to use zinc dithiophosphate and an amine-based antioxidant in combination. Moreover, it is preferable that the mixture ratio of these antioxidants is 0.5-5 weight part in total with respect to 100 weight part of total amounts of a base oil and a thickener.

Examples of zinc dithiophosphate (zinc dithiophosphate; hereinafter referred to as “ZnDTP”) include zinc dialkyldithiodithiophosphate and zinc diaryldithiophosphate represented by the following formula (5).

R ₅ in the formula represents a primary or secondary alkyl group having 1 to 24 carbon atoms or an aryl group having 6 to 30 carbon atoms. Examples of R ₅ include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a secondary butyl group, an isobutyl group, a pentyl group, a 4-methylpentyl group, a hexyl group, a 2-ethylhexyl group, and a heptyl group. Octyl group, nonyl group, decyl group, isodecyl group, dodecyl group, tetradecyl group, hexadecyl group, octadecyl group, eicosyl group, docosyl group, tetracosyl group, cyclopentyl group, cyclohexyl group, methylcyclohexyl group, ethylcyclohexyl group, dimethylcyclohexyl Group, cycloheptyl group, phenyl group, tolyl group, xylyl group, ethylphenyl group, propylphenyl group, butylphenyl group, pentylphenyl group, hexylphenyl group, heptylphenyl group, octylphenyl group, nonylphenyl group, decylpheny group Group, dodecylphenyl group, tetradecylphenyl group, hexadecylphenyl group, octadecylphenyl group, benzyl group and the like. Each R ₅ may be the same or different.

Among these, R ₅ is preferably a primary alkyl group because it is excellent in stability and contributes to prevention of peeling on the rolling surface due to hydrogen embrittlement. When R ₅ is an alkyl group, the greater the number of carbon atoms, the better the heat resistance and the easier it is to dissolve in the base oil. On the other hand, the smaller the number of carbon atoms, the better the abrasion resistance and the less soluble in the base oil. As a preferable commercially available product of ZnDTP, for example, ADEKA Corporation: Adeka Klube Z112 and the like can be mentioned.

  The grease composition preferably does not contain a solid powder that does not dissolve in the base oil. “Not dissolved in base oil” means, for example, that 0.5% by weight of solid powder is added to the base oil and stirred with respect to the total weight after dissolution, and this is visually observed after being held at 70 ° C. for 24 hours. As a result, it refers to a solid powder in which an insoluble component is precipitated in the base oil. If the insoluble matter is precipitated, the base oil is not transparent, and the solid powder becomes colloidal or suspended, which can be judged visually. Examples of such solid powder include aluminum, silicon, titanium, tungsten, molybdenum, chromium, cobalt, gold, silver, copper, yttrium, zirconium, iridium, palladium, platinum, rhodium, ruthenium, hafnium, tantalum, tungsten, Examples thereof include metal powders such as rhenium and osmium. Even if these metal powders are not blended in the present invention, peeling on the rolling surface due to hydrogen embrittlement can be prevented by blending alkanolamine (liquid or paste).

  An example of a rolling bearing for automobile electrical equipment / auxiliary machinery according to the present invention will be described with reference to FIG. FIG. 1 is a cross-sectional view of a rolling bearing (deep groove ball bearing). In the rolling 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. The rolling element 4 is held by a cage 5. If necessary, the axially opposite end openings 8 a and 8 b of the inner and outer rings are sealed by the seal member 6, and the above-described grease composition 7 is sealed around the rolling element 4.

  In the rolling bearing 1, the ferrous metal material constituting the bearing member such as the inner ring 2, the outer ring 3, the rolling element 4, and the cage 5 is an arbitrary material generally used as a bearing material. Bearing steel (SUJ1, SUJ2, SUJ3, SUJ4, SUJ5, etc .; JIS G 4805), carburized steel (SCr420, SCM420, etc .; JIS G 4053), stainless steel (SUS440C, etc .; JIS G 4303), high speed steel (M50, etc.) And cold rolled steel. The seal member 6 may be a metal or rubber molded body alone, or may be a composite of a rubber molded body and a metal plate, a plastic plate, or a ceramic plate. From the viewpoint of durability and ease of fixing, a composite of a rubber molded body and a metal plate is preferable.

  Ball bearings are exemplified as rolling bearings for automobile electrical equipment and auxiliary machines according to the present invention, but cylindrical roller bearings, tapered roller bearings, self-aligning roller bearings, needle roller bearings, thrust cylindrical roller bearings, thrust tapered roller bearings other than those described above Also, it can be a rolling bearing such as a thrust needle roller bearing or a thrust self-aligning roller bearing.

  Another embodiment of a rolling bearing for automobile electrical equipment / auxiliary machinery according to the present invention is shown in FIGS. 2 (a) and 2 (b). 2A and 2B are cross-sectional views of the structure of the fan coupling device. The fan coupling device includes an oil chamber 11 in which a viscous fluid such as silicone oil is filled in a case 10 that supports a cooling fan 9 and a stirring chamber 12 in which a drive disk 18 is incorporated. A port 14 is formed in the partition plate 13 provided therebetween, and an end of a spring 15 that opens and closes the port 14 is fixed to the partition plate 13. A cooling fan 9 is rotatably supported by the rolling bearing 1 in which the above-described grease composition is enclosed. A bimetal 16 is attached to the front surface of the case 10, and a piston 17 of a spring 15 is provided on the bimetal 16. The bimetal 16 becomes flat when the temperature of the air that has passed through the radiator is below a set temperature, for example, 60 ° C., the piston 17 presses the spring 15, and the spring 15 closes the port 14. When the air temperature exceeds the set temperature, the bimetal 16 is bent outward as shown in FIG. 2B, the piston 17 releases the pressure of the spring 15, and the spring 15 is elastically deformed. Port 14 is opened.

  When the temperature of the air that has passed through the radiator is lower than the set temperature of the bimetal 16 in the operating state of the fan coupling device having the above configuration, the port 14 is closed by the spring 15 as shown in FIG. Therefore, the viscous fluid in the oil chamber 11 does not flow into the stirring chamber 12, and the viscous fluid in the stirring chamber 12 enters the oil chamber 11 from the circulation hole 19 provided in the partition plate 13 by the rotation of the drive disk 18. Sent. For this reason, the amount of the viscous fluid in the stirring chamber 12 becomes small, and the shear resistance due to the rotation of the drive disk 18 becomes small. Therefore, the transmission torque to the case 10 is reduced and the cooling bearing supported by the rolling bearing 1 is used. The fan 9 rotates at a low speed. When the temperature of the air that has passed through the radiator exceeds the set temperature of the bimetal 16, the bimetal 16 is bent outward as shown in FIG. 2B, and the piston 17 releases the pressure of the spring 15. At this time, since the spring 15 is elastically deformed in a direction away from the partition plate 13, the port 14 is opened, and the viscous fluid in the oil chamber 11 flows from the port 14 into the stirring chamber 12. For this reason, the shear resistance of the viscous fluid due to the rotation of the drive disk 18 increases, the rotational torque to the case 10 increases, and the cooling fan 9 supported by the rolling bearing 1 rotates at high speed.

  As described above, in the fan coupling device, the rotational speed of the cooling fan 9 changes according to the temperature change, so that warming up is accelerated and overcooling of the cooling water is prevented to effectively cool the engine. Can do. The cooling fan 9 is equivalent to being disconnected from the drive shaft 20 when the engine temperature is low, and is equivalent to being connected to the drive shaft 20 when the engine temperature is high. As described above, the rolling bearing 1 is used in a wide temperature range from a low temperature to a high temperature, and in a rapid acceleration / deceleration condition in which the number of rotations greatly fluctuates with a change in temperature.

  A rolling bearing for automobile electrical equipment and auxiliary equipment used in an alternator as another embodiment of the rolling bearing for automobile electrical equipment and auxiliary equipment of the present invention will be described with reference to FIG. FIG. 3 is a sectional view of the structure of the alternator. In the alternator, a rotor rotating shaft 23 in which a rotor 22 is mounted on a pair of frames 21a and 21b forming a housing which is a stationary member is rotatable by a pair of rolling bearings 1 and 1 in which the above-described grease composition is enclosed. It is supported by. A rotor coil 24 is attached to the rotor 22, and a three-turn stator coil 26 is attached to the stator 25 disposed on the outer periphery of the rotor 22 at a phase of 120 °. The rotor rotating shaft 23 is rotationally driven with a rotational torque transmitted by a belt (not shown) to a pulley 27 attached to the tip thereof. The pulley 27 is attached to the rotor rotating shaft 23 in a cantilever state, and vibration is also generated as the rotor rotating shaft 23 rotates at high speed. Therefore, the rolling bearing 1 that supports the pulley 27 side in particular receives a severe load. .

  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 structure of the idler pulley. The pulley includes a pulley body 28 made of a steel plate press and a single row rolling bearing 1 (see FIG. 1) fitted to the inner diameter of the pulley body 28. The pulley main body 28 includes an inner diameter cylindrical portion 28a, a flange portion 28b extending from one end of the inner diameter cylindrical portion 28a to the outer diameter side, an outer diameter cylindrical portion 28c extending in the axial direction from the flange portion 28b, and an inner diameter cylindrical portion 28a. This is an annulus composed of a flange portion 28d extending from the other end to the inner diameter side. The outer ring 3 of the rolling bearing 1 shown in FIG. 1 is fitted to the inner diameter of the inner diameter cylindrical portion 28a, and the outer peripheral diameter of the outer diameter cylindrical portion 28c is provided with a pulley peripheral surface 28e that contacts a belt driven by the engine. ing. By bringing the pulley peripheral surface 28e into contact with the belt, the pulley functions as an idler.

  The present invention will be specifically described with reference to examples and comparative examples, but is not limited to these examples.

[Evaluation of acid value]
The effect of acid value reduction by the combination of dialkanolamine and base oil was evaluated. Table 1 shows the combinations evaluated (Reference Examples 1 to 14). About what added the alkanolamine, 2 weight part of alkanolamine was added with respect to 100 weight part of base oils. The added alkanolamine is diethanolamine (ADEKA CLUB FM-812 manufactured by ADEKA). Further, PAO is Shinfluid 801 manufactured by Nippon Steel Chemical Co., Ltd., ester oil is H2362 manufactured by HATCO, and alkyl diphenyl ether oil is Moresco High Lube LB100 manufactured by Matsumura Oil Research Institute.

  The acid value (mgKOH / g) when 10 g of the base oil shown in Table 1 was collected in a 30 mL beaker (containing 2 g of iron powder in advance) and allowed to stand at 150 ° C. for 260 hours was measured by a neutralization titration method. . The results are shown in Table 1 and FIG.

  As shown in Table 1 and FIG. 5, in Reference Example 8 in which alkanolamine was added to PAO, the acid value increased compared to Reference Example 1 in which the PAO oil alone was used. In addition, the acid value of the oil containing ester oil decreased due to the addition of alkanolamine.

Examples 1 to 6 and Comparative Examples 1 to 8
First, the base oil was adjusted by mixing the base oil as shown in Table 2 alone or by mixing. Next, 4,4′-diphenylmethane diisocyanate (Millionate MT manufactured by Nippon Polyurethane Industry, hereinafter referred to as “MDI”) is dissolved in half of this base oil, and the remaining half of the base oil is twice the equivalent of MDI. Cyclohexylamine was dissolved. Add the solution in which cyclohexylamine is dissolved while stirring the solution in which MDI is dissolved, and then continue the reaction at 100 to 120 ° C. for 30 minutes to react to form an alicyclic diurea compound in the base oil. Obtained. The blending ratio of each component constituting the thickener was adjusted so that the alicyclic diurea compound produced with respect to the entire grease had the weight ratio shown in Table 1. To this, alkanolamine was added at a blending ratio shown in Table 1 and further sufficiently stirred. Thereafter, it was homogenized with three rolls to obtain a test grease.

  The obtained grease was sealed in a rolling bearing and a rapid acceleration / deceleration test was conducted. Test methods and test conditions are shown below.

<Rapid acceleration / deceleration test>
An alternator, which is an example of an electrical accessory, was simulated, and the grease was enclosed in an inner ring rolling bearing (the inner ring / outer ring / steel ball is bearing steel SUJ2) that supports the rotating shaft, and a rapid acceleration / deceleration test was performed. The rapid acceleration / deceleration test conditions are as follows: In a 120 ° C atmosphere, the load is applied to the pulley attached to the tip of the rotating shaft at 1960 N, the rotation speed is set at 0 rpm to 18000 rpm, and the grease is used to promote the exposure of the new surface due to wear. 1% by weight of iron powder was mixed in, and a test was performed in a state where a current of 1.0 A flows in the test bearing (6203). Then, abnormal peeling occurred in the bearing, and the time when the vibration of the vibration detector exceeded the set value and stopped (peeling life time) was measured. Table 2 shows the case where the peeling life time was 20 hours or longer as “peeling test: ◯”, and the case where it was less than 20 hours as “peeling test: x”.

  For the base oils used in the examples and comparative examples, the above reference example was referred to, and the case where the acid value after lapse of 260 hours was 4.00 mgKOH / g or less was designated as “high temperature endurance test: ◯” The case where the value exceeds 4.00 mgKOH / g is defined as “High temperature endurance test: x” and shown in Table 2. In Table 2, the alkanolamine added is referred to “Yes” for the alkanolamine added in the above Reference Example, and the alkanolamine added in the above Reference Example is “No”. "

  As shown in Table 2, in each example in which alkanolamine (diethanolamine) was blended, the peeling occurrence life time could be extended as compared with each comparative example. This is considered to be because specific exfoliation accompanied by white texture change due to hydrogen embrittlement generated on the rolling surface could be effectively prevented. On the other hand, in Comparative Examples 2 to 8 in which no alkanolamine was blended, the peel resistance was inferior.

  Since the rolling bearing of the present invention can prevent peeling on the rolling surface due to hydrogen embrittlement and has excellent high temperature durability, it can be used in alternators, electromagnetic clutches for car air conditioners, fan coupling devices, intermediate pulleys, electric fan motors, etc. It can be suitably used as a rolling bearing for automobile electrical parts and auxiliary equipment.

DESCRIPTION OF SYMBOLS 1 Rolling bearing 2 Inner ring 3 Outer ring 4 Rolling body 5 Cage 6 Seal member 7 Grease composition 8a, 8b Opening 9 Cooling fan 10 Case 11 Oil chamber 12 Stirring chamber 13 Partition plate 14 Port 15 Spring 16 Bimetal 17 Piston 18 Drive Disc 19 Distribution hole 20 Drive shaft 21a, 21b Frame 22 Rotor 23 Rotor rotation shaft 24 Rotor coil 25 Stator 26 Stator coil 27 Pulley 28 Pulley body

Claims (6)

A rolling bearing for automobile electrical equipment and auxiliary equipment that rotatably supports a rotating shaft that is driven to rotate by engine output on a stationary member,
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, a seal member that covers openings in both axial directions of the inner ring and the outer ring, and an iron system that is enclosed around the rolling element. A grease composition that lubricates the contact surfaces between metal members ,
The grease composition contains a base oil, a thickener, and an alkanolamine, and does not contain an alkali metal salt or an alkaline earth metal salt of an inorganic acid;
The base oil contains (A) an alkyldiphenyl ether oil as an essential component in an amount of 25% by weight or more based on the whole base oil, or (B) an ester oil as an essential component in an amount of 25% by weight or more based on the whole base oil. Rolling bearings for automobile electrical equipment and auxiliary equipment, characterized by being oil.   The rolling bearing for automobile electrical equipment / auxiliary equipment according to claim 1, wherein the alkanolamine is dialkanolamine or trialkanolamine.   The rolling bearing for automobile electrical equipment / auxiliary machinery according to claim 2, wherein the alkanolamine is diethanolamine.   4. The rolling bearing for automobile electrical equipment / auxiliary equipment according to claim 1, wherein the thickener is an alicyclic diurea compound.   The rolling bearing for automobile electrical equipment / auxiliary machinery according to any one of claims 1 to 4, wherein the alkanolamine is contained in an amount of 0.1 to 10% by weight based on the entire grease composition.   The rolling bearing for automobile electrical equipment / auxiliary machinery according to any one of claims 1 to 5, wherein the base oil contains poly-α-olefin oil.