Grease composition and rolling bearing

Abstract

Provided are: a grease composition which has low dust emission, anti-rust properties and high-temperature and high-speed durability at the same time; and a rolling bearing in which the grease composition is sealed. The grease composition (7) contains a base oil, a thickener and a rust inhibitor, the base oil contains a synthetic hydrocarbon oil as the main component and does not contain an ester oil, the base oil has a kinematic viscosity of 40 mm2 / s to 90 mm2 / s at 40 DEG C, the thickener is a diurea compound obtained by reacting a diisocyanate component and a monoamine component, the monoamine component is an aliphatic monoamine and an alicyclic monoamine, and the rust inhibitor is a mixture of an aliphatic monoamine and an alicyclic monoamine. The content of the thickening agent is less than 14 mass% with respect to the total amount of the base oil and the thickening agent, the rust inhibitor contains a sorbitan fatty acid ester, and the grease composition has a mixed consistency of 200-240 as measured in accordance with JIS K 2220.

Description

Technical Field

[0001] The present invention relates to a grease composition and a rolling bearing enclosed with the grease composition, and in particular to a grease composition and a rolling bearing used in rolling bearings used under high temperature and high speed rotation, such as industrial machinery engines (motors) used in home appliances or industrial equipment, and drive engines used in electric vehicles (EVs) or hybrid electric vehicles (HEVs). Background Art

[0002] The bearings used in the rotating support parts of motor machinery represented by electric motors have grease enclosed inside. In such bearings, the grease is usually sealed using a sealing plate (sealing component) such as a rubber seal that is a rubber material vulcanized and bonded to an iron plate or a mandrel.

[0003] In recent years, these bearings have been operating at higher temperatures and higher speeds, requiring better high-temperature and high-speed durability (extending the life of the grease). In addition, non-contact seals are used to reduce torque, but as the speed increases, the oily dust generated from the grease inside the bearing may adhere to electronic components such as encoders and cause failures.

[0004] For example, the driving engine bearings of EVs and HEVs are used in an environment of about 120° C. to 150° C. As a grease composition for such driving engine bearings, a grease composition using a specific ester oil in a specific diurea compound has been proposed (see Patent Document 1). Prior art literature Patent Literature

[0005] Patent Document 1: International Publication No. 2013 / 015413 Summary of the invention Problems to be solved by the invention

[0006] However, Patent Document 1 does not study low dust generation and rust prevention properties, and is therefore insufficient as a grease composition for engine bearings and the like in recent years that requires low dust generation, rust prevention, and high-temperature and high-speed durability.

[0007] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a grease composition that achieves low dust generation, rust prevention, and high-temperature and high-speed durability, and a rolling bearing enclosed with the grease composition. Means of solving problems

[0008] The grease composition of the present invention is a grease composition containing a base oil, a thickener and a rust inhibitor, characterized in that the base oil is mainly composed of a synthetic hydrocarbon oil and does not contain an ester oil, and the dynamic viscosity at 40° C. is 40 mm2 / s~90mm 2 / s, the thickener is a diurea compound obtained by reacting a diisocyanate component with a monoamine component, the monoamine component is an aliphatic monoamine and an alicyclic monoamine, the content of the thickener is less than 14% by mass relative to the total amount of the base oil and the thickener, the rust inhibitor contains sorbitan fatty acid ester, and the mixed consistency of the grease composition measured according to JIS K2220 is 200 to 240.

[0009] The grease composition is characterized in that the sorbitan fatty acid ester is sorbitan trioleate.

[0010] The grease composition is characterized in that, in the thickener, the number of moles of the aliphatic monoamine is greater than the number of moles of the alicyclic monoamine.

[0011] The rolling bearing of the present invention is a rolling bearing comprising an inner ring, an outer ring, a plurality of rolling elements between the inner ring and the outer ring, sealing components arranged at openings at both axial ends of the inner ring and the outer ring, and a grease composition enclosed in the bearing space, and is characterized in that the grease composition is the grease composition of the present invention.

[0012] The above rolling bearing is characterized in that the cage is a cage made of polyamide resin.

[0013] The rolling bearing is characterized in that the sealing member is a non-contact type sealing member fixed to one of the inner ring and the outer ring and opposed to the other member with a gap therebetween.

[0014] The above rolling bearing is subjected to high temperature conditions of 100°C to 150°C and the dm·n value is 50×10 4 ~180×10 4 Used under high-speed conditions.

[0015] The rolling bearing is characterized in that it is a bearing for an engine (motor). Effects of the Invention

[0016] The grease composition of the present invention comprises: a synthetic hydrocarbon oil as a main component and no ester oil, and a dynamic viscosity of 40 mm at 40°C. 2 / s~90mm 2 / s base oil; a predetermined amount of diurea thickener obtained by reacting a diisocyanate component with a monoamine component (aliphatic monoamine and alicyclic monoamine); and a sorbitan fatty acid ester as a rust preventive, the grease composition has a mixed consistency of 200 to 240 as measured in accordance with JIS K 2220, and therefore can take into account both rust prevention and oil separation during high-temperature and high-speed rotation (the supply of oil from the grease separated by the channeling effect to the contact part). For example, for a combination of a predetermined base oil and a predetermined thickener, by adding a sorbitan fatty acid ester, it is possible to impart rust prevention while maintaining the low dust generation of the synthetic hydrocarbon oil without affecting the surface tension of the base oil.

[0017] Since the sorbitan fatty acid ester is sorbitan trioleate, the grease composition has excellent rust prevention properties and low dust generation.

[0018] In the thickener, the molar number of the aliphatic monoamine is larger than the molar number of the alicyclic monoamine, and therefore, as shown in Examples described below, the low dust generation property is more excellent.

[0019] The rolling bearing of the present invention seals the grease composition of the present invention in the bearing space and is suitable for use in bearings used in motor machines such as engines, and can contribute to higher temperatures and higher speeds and improved reliability of the motor machines. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a cross-sectional view of a deep groove ball bearing as an example of the rolling bearing of the present invention. Figure 2 It is a cross-sectional view of a deep groove ball bearing which is another example of the rolling bearing of the present invention. Figure 3 It is a cross-sectional view of an engine using the rolling bearing of the present invention. DETAILED DESCRIPTION

[0021] The grease composition of the present invention is characterized by containing a predetermined base oil, a predetermined thickener, and a predetermined rust inhibitor.

[0022] The base oil used in the grease composition of the present invention contains synthetic hydrocarbon oil as a main component and does not contain ester oil. The dynamic viscosity at 40°C (in the case of a mixed oil, the dynamic viscosity of the mixed oil) is 40 mm 2 / s~90mm 2 / s. The dynamic viscosity is preferably 40 mm at 40°C. 2 / s~70mm 2 / s, preferably 40 mm 2 / s~55mm 2 / s.

[0023] As the synthetic hydrocarbon oil, poly-α-olefin oil (PAO oil) is more preferred. PAO oil is a mixture of oligomers or polymers of α-olefins or isomerized α-olefins. Specific examples of α-olefins 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-tetracosene, etc., and mixtures thereof are usually used.

[0024] The base oil contains synthetic hydrocarbon oil as a main component, and its content is 50% by mass or more, preferably 80% by mass or more, based on the total base oil. As the base oil, only synthetic hydrocarbon oil (for example, 100% PAO oil) may be used.

[0025] The base oil used in the present invention may also contain other base oils. For example, mineral oils such as paraffin-based mineral oils, cycloparaffin-based mineral oils, ether oils such as alkyl diphenyl ether oils, silicone oils, fluorinated oils, and mixed oils thereof may be used. However, the base oil used in the present invention does not contain ester oil. Examples of ester oils include diester oils obtained by reacting dibasic acids with branched alcohols, aromatic ester oils obtained by reacting aromatic tribasic acids with branched alcohols, and polyol ester oils obtained by reacting polyols with monobasic acids. As shown in the examples, the base oil is mainly composed of PAO oil, and when it contains ester oil, the amount of dust generated increases. It should be noted that the ester oils mentioned here do not include sorbitan fatty acid esters.

[0026] The thickener used in the grease composition of the present invention is a diurea compound obtained by reacting a diisocyanate component with a monoamine component. In the present invention, as the monoamine component, an aliphatic monoamine and an alicyclic monoamine can be used. As the diisocyanate component, phenyl diisocyanate, toluene diisocyanate, diphenyl diisocyanate, diphenylmethane diisocyanate, octadecane diisocyanate, decane diisocyanate, hexane diisocyanate, etc. can be mentioned. As the aliphatic monoamine, hexylamine, octylamine, dodecylamine, hexadecylamine, stearylamine, oleylamine, etc. can be mentioned. As the alicyclic monoamine, cyclohexylamine, etc. can be mentioned.

[0027] In the thickener, the relationship between the molar numbers of the aliphatic monoamine and the alicyclic monoamine as raw materials of the diurea compound is not particularly limited. From the viewpoint of low dust generation, it is preferred that the molar number of the aliphatic monoamine is greater than the molar number of the alicyclic monoamine. Specifically, the molar ratio (the molar number of the aliphatic monoamine / the molar number of the alicyclic monoamine) is preferably greater than 1.0 and not more than 4.0, and more preferably 1.5 to 3.0.

[0028] A base grease is obtained by mixing a diurea compound as a thickener in a base oil. The base grease using a diurea compound as a thickener is prepared by reacting a diisocyanate component with a monoamine component in a base oil. The amount of the thickener relative to the total amount of the base oil and the thickener (100% by mass) is less than 14% by mass, preferably 5% by mass to 13% by mass, more preferably 8% by mass to 13% by mass, and even more preferably 10% by mass to 13% by mass.

[0029] The grease composition of the present invention contains sorbitan fatty acid ester as a rust inhibitor. By adding sorbitan fatty acid ester, rust prevention can be imparted to the grease composition while maintaining low dust generation. Examples of the sorbitan fatty acid ester include sorbitan fatty acid monoesters such as sorbitan monolaurate, sorbitan monostearate, and sorbitan monooleate, and sorbitan trioleate. Among them, sorbitan trioleate is preferred.

[0030] The amount of sorbitan fatty acid ester is preferably 0.5 to 3 parts by mass, more preferably 0.5 to 2 parts by mass, and still more preferably 0.5 to 1.5 parts by mass relative to 100 parts by mass of the total amount of the base oil and the thickener. By setting it within these ranges, it is easier to achieve both low dust generation and rust resistance.

[0031] As shown in the Examples, when an amine rust inhibitor or a succinate rust inhibitor is added as a rust inhibitor, the amount of dust generation tends to increase. Therefore, the grease composition preferably does not contain any other rust inhibitor (amine rust inhibitor, succinate rust inhibitor, sulfonate rust inhibitor, etc.) other than sorbitan fatty acid ester.

[0032] In addition, the grease composition of the present invention may be added with known additives as required. Examples of the additives include antioxidants such as amines, phenols, and sulfur compounds; extreme pressure agents such as tricresyl phosphate and other phosphates, tricresyl phosphites and other phosphites, thiophosphates, thiophosphites, zinc alkyl dithiophosphates (ZnDTP), molybdenum alkyl dithiophosphates (MoDTP), and zinc dithiocarbamates (ZnDTC).

[0033] The mixed viscosity (JIS K 2220) of the grease composition of the present invention is in the range of 200 to 240. From the viewpoint of high-speed rotation, it is preferred that the oil is easily separated, and from the viewpoint of low dust generation, it is preferred that the oil is not easily separated. In the present invention, based on the combination of a predetermined base oil, a predetermined thickener, and a predetermined rust inhibitor, by making the viscosity within the above range, a grease composition having low dust generation, rust resistance, and high-speed durability in a well-balanced manner is obtained. Furthermore, from the viewpoint of low dust generation, the mixed viscosity is preferably in the range of 200 to 220.

[0034] based on Figure 1 , illustrating a rolling bearing encapsulated with the grease composition of the present invention. Figure 1 : is a cross-sectional view of a deep groove ball bearing. In a rolling bearing 1, an inner ring 2 having an inner ring raceway surface 2a on the outer circumference and an outer ring 3 having an outer ring raceway surface 3a on the inner circumference are arranged concentrically. A plurality of rolling elements 4 are arranged between the inner ring raceway surface 2a and the outer ring raceway surface 3a. The rolling elements 4 are held by a retainer 5. In addition, the axial end openings 8a and 8b of the inner and outer rings are sealed by a sealing member 6, and the above-mentioned grease composition 7 is sealed at least around the rolling elements 4. Figure 1 The sealing component 6 is a contact type sealing component in which the inner diameter lip contacts the inside of the sealing groove of the inner ring 2. The inner ring 2, the outer ring 3 and the rolling element 4 are mainly composed of iron-based metal materials, and the grease composition 7 is interposed on the raceway surface of the rolling element 4 for lubrication.

[0035] In the rolling bearing 1, the iron-based metal material constituting the bearing components of the inner ring 2, the outer ring 3, and the rolling element 4 is any material commonly used as a bearing material, for example: high carbon chromium bearing steel (SUJ1, SUJ2, SUJ3, SUJ4, SUJ5, etc.; JIS G 4805), carburizing steel (SCr420, SCM420, etc.; JIS G 4053), stainless steel (SUS440C, etc.; JIS G 4303), high-speed steel (M50, etc.), cold-rolled steel, etc.

[0036] The retainer 5 is formed of an iron material or a resin material. As the iron material, any material commonly used as a retainer can be used, for example, cold-rolled steel plate for retainer (SPCC; JIS G 3141), stainless steel (SUS 440C, etc.; JIS G 4303), carbon steel for retainer (JIS G 4051), high-strength brass casting for retainer (JIS H 5102), etc. In addition, as the resin material, for example, phenolic resin, polyetheretherketone (PEEK) resin, polyphenylene sulfide (PPS) resin, thermoplastic polyimide resin, polyamide-imide resin, a resin material using polyamide resin such as polyamide 66 resin and polyamide 46 resin as a resin matrix and reinforcing fibers such as carbon fiber and glass fiber and other additives can be used.

[0037] based on Figure 2 Another embodiment of the rolling bearing of the present invention is described. Figure 1 The same structures are marked with the same symbols and detailed description is omitted. Figure 1 The deep groove ball bearings use contact type seal components, while Figure 2A non-contact type sealing component is used in a deep groove ball bearing. The axial end openings of the inner and outer rings of the deep groove ball bearing 9 are sealed by a sealing component 10, and the above-mentioned grease composition 7 is sealed at least around the rolling element 4. The sealing component 10 forms a labyrinth gap with the inner diameter lip and the inside of the seal groove of the inner ring 2, making it non-contact type. Since the grease composition of the present invention has excellent low dust generation, it can be applied to rolling bearings with non-contact type sealing components. In addition, by making the sealing component non-contact type, further low torque can be achieved.

[0038] exist Figure 1 and Figure 2 In the figure, a ball bearing is exemplified as a bearing, but the rolling bearing of the present invention can also be used as a cylindrical roller bearing, a tapered roller bearing, a self-aligning roller bearing, a needle roller bearing, a thrust cylindrical roller bearing, a thrust tapered roller bearing, a thrust needle roller bearing, a thrust self-aligning roller bearing, etc.

[0039] The rolling bearing of the present invention can be used as a bearing for supporting a rotor of an engine for driving industrial machinery, electrical equipment, or electric vehicles, for example. Figure 3 An example in which the rolling bearing of the present invention is applied to, for example, an engine (motor) is shown. Figure 3 : is a cross-sectional view of the structure of the engine. The engine has: a stator 12, which is composed of an engine magnet arranged on the inner peripheral wall of the sleeve 11; a rotor 15, which is wound on a winding 14 fixed to a rotating shaft 13; a commutator 16, which is fixed to the rotating shaft 13; a brush holder 17, which is arranged on an end frame 19 supported by the sleeve 11; and a brush 18, which is accommodated in the brush holder 17. The rotating shaft 13 is rotatably supported by the sleeve 11 through a deep groove ball bearing 1 and a support structure for the bearing 1. The bearing 1 is a rolling bearing of the present invention.

[0040] As engines (motors) to which the rolling bearing of the present invention can be applied, there can be cited: engines for industrial machinery such as ventilator engines, fuel cell blower engines, cleaner engines, fan engines, servo engines, stepping engines, etc., automobile starting engines, electric power steering engines, tilt engines for steering adjustment, blower engines, wiper engines, electric window engines, etc., engines for electric vehicles or hybrid vehicles, etc. The present invention is particularly suitable for bearings that require low dust generation, rust resistance, and can be used at high temperatures and high speeds, but is not limited to engine bearings.

[0041] As described above, the rolling bearing of the present invention is suitable for use under high temperature and high speed conditions. As a high temperature condition, specifically, the outer diameter temperature of the bearing outer ring is 80°C or higher, preferably 100°C or higher. The upper limit of the outer diameter temperature of the bearing outer ring is not particularly limited, for example, 180°C, preferably 150°C. As a high speed condition, specifically, the dm·n value is 50×10 4 Above, preferably 70×10 4 The upper limit of the dm·n value is not particularly limited, but is, for example, 200×10 4 , preferably 180×10 4 For example, the grease lubricated bearings of the driving engine of EV or HEV are subjected to high temperature conditions of 100℃ to 150℃ and the dm·n value is 70×10 4 ~180×10 4 The rolling bearing of the present invention has low dust generation, rust resistance and excellent grease life under such a use environment. Example

[0042] Grease compositions of the compositions shown in Tables 1 and 2 were prepared respectively. In Tables 1 and 2, the contents of the base oil, thickener, and rust inhibitor represent the contents (mass %) relative to the base grease (base oil + thickener). In Tables 1 and 2, PAO oil was used as the synthetic hydrocarbon oil, and the grease composition consisted of only the base oil, thickener, and rust inhibitor. In addition, the meanings of 1) to 9) described below Table 1 are the same in Table 2.

[0043] <Dust generation test> Each grease composition was sealed in a ball bearing 608 (8 mm inner diameter, 22 mm outer diameter, 7 mm width) equipped with a non-contact seal component to produce a test bearing. As a retainer, a resin retainer (polyamide 66 resin + glass fiber 25% by mass) was used in Example 5, and an iron retainer was used in other examples. The obtained test bearings were subjected to an axial load of 9.8 N for 5000 min. -1 The inner ring was rotated at a rotation speed of 1000 for 8 hours. The dust (dust) with a particle size of 0.1 μm or more generated 30 minutes before the end of the 8-hour test (9 liters of suction volume) was measured using a particle counter with a suction volume of 0.3 liters / minute. Regarding the evaluation of the dust volume, less than 30,000 were evaluated as "A", more than 30,000 and less than 45,000 were evaluated as "B", more than 45,000 and less than 60,000 were evaluated as "C", and more than 60,000 were evaluated as "D", which are listed in Tables 1 and 2.

[0044] <Grease life test> 1.8 g of each grease composition was sealed in a ball bearing 6204 (20 mm inner diameter, 47 mm outer diameter, 14 mm width) equipped with a non-contact seal (equivalent to 38% of the total space) to produce a test bearing. The test bearing was subjected to a temperature of 150°C at the outer diameter of the bearing outer ring, an axial load of 67 N, and a radial load of 67 N for 15,000 min. -1 The time until heat generation and seizure occurs is measured. The dm·n value under this condition is 50×10 4 The grease life time was evaluated as "A" for more than 2500 hours, "B" for 1500 to 2500 hours, "C" for 1000 to less than 1500 hours, and "D" for less than 1000 hours. The results are shown in Tables 1 and 2.

[0045] [Table 1] 1) 47mm 2 / s@40℃(manufactured by イネオス Co., Ltd., デュラシン168) 2) 65mm 2 / s@40℃(manufactured by イネオス Co., Ltd., デュラシン170) 3) 30mm 2 / s@40℃(manufactured by イネオス Co., Ltd., デュラシン146) 4) 162mm 2 / s@40℃(Mitsui Chemical Co., Ltd., Rikono HC20) 5) 46mm 2 / s@40℃(made by NOF, ユニスターHR-46) 6)Sorbitan trioleate 7) KING, NA-SUL EDS 8) Made by Nippon Oil Co., Ltd. 150 9)(Number of moles of stearylamine) / (Number of moles of cyclohexylamine) 10) Only Example 5 uses a resin (PA66+GF25%) retainer, while other examples use an iron retainer

[0046] [Table 2]

[0047] As shown in Table 1, Examples 1 to 7, which are composed of a base oil composed of PAO oil and having a predetermined dynamic viscosity, a thickener composed of a diurea compound using an aliphatic monoamine and an alicyclic monoamine as a monoamine component, and a sorbitan fatty acid ester, showed good results in all tests. In the case of using a resin retainer as a retainer (Example 5), the grease life was extended compared to the case of using an iron retainer. In addition, for the thickener, when the molar number of the aliphatic monoamine as the monoamine component used as a raw material was larger than the molar number of the alicyclic monoamine, a result excellent in low dust generation was obtained.

[0048] As shown in Table 2, when ester oil is added to the base oil (Comparative Example 1), the dust generation amount increases even though the base oil viscosity and consistency are the same as those of Examples 1 to 7. The grease life of Comparative Example 2, in which the base oil viscosity is low, is significantly reduced. When an amine (amine salt of alkyl aromatic sulfonic acid) or succinate is used as a rust inhibitor (Comparative Examples 3 and 4), the dust generation amount increases compared to the use of sorbitan fatty acid ester (for example, Example 1). It is speculated that the increase or decrease in the dust generation amount is affected by the surface tension of the base oil. By adding an amine or succinate rust inhibitor, the surface tension of the base oil is reduced, resulting in an increase in the dust generation amount. When the consistency is less than 200 (Comparative Example 6), the grease composition becomes hard, resulting in a reduction in the grease life. In addition, when the consistency exceeds 240 (Comparative Example 7), the grease composition becomes soft, resulting in an increase in the dust generation amount.

[0049] In summary, the grease composition of the present invention combines a specified base oil, a specified thickener and a specified rust inhibitor, further optimizes the viscosity, makes the oil separation from the grease appropriate, and achieves a balance between low dust generation, rust prevention and long life under high-speed and high-temperature rotation. Industrial Applicability

[0050] The grease composition of the present invention can achieve low dust generation, rust resistance and high-temperature and high-speed durability, and can therefore be suitably used, for example, in rolling bearings for rotary electrical machinery such as servomotors and encoders that require low dust generation, and bearings for drive engines of EVs or HEVs.

[0051] Description of Reference Numerals 1 Rolling bearings 2 Inner ring 3 Outer ring 4 Rolling elements 5 Retainer 6 Sealing parts 7 Grease 8a, 8b opening 9 Rolling bearings 10 Sealing parts 11. Sheath 12 Stator 13 Rotation axis 14 Winding 15 Rotor 16 Commutator 17 Brush Holder 18 Brush 19 End frame

Claims

1. A grease composition comprising a base oil, a thickener and a rust inhibitor, characterized in that: The base oil is mainly composed of synthetic hydrocarbon oil and does not contain ester oil. The dynamic viscosity at 40°C is 40 mm 2 / s~90mm 2 / s, The thickener is a diurea compound obtained by reacting a diisocyanate component with a monoamine component, the monoamine component is an aliphatic monoamine and an alicyclic monoamine, and the content of the thickener is less than 14% by mass relative to the total amount of the base oil and the thickener. The rust inhibitor contains sorbitan fatty acid ester, The grease composition has a mixing consistency of 200 to 240 as measured according to JIS K 2220.

2. The grease composition according to claim 1, characterized in that The sorbitan fatty acid ester is sorbitan trioleate.

3. The grease composition according to claim 1, characterized in that In the thickener, the mole number of the aliphatic monoamine is greater than the mole number of the alicyclic monoamine.

4. The grease composition according to claim 1, characterized in that In the rust inhibitor, the sorbitan fatty acid ester is sorbitan trioleate and does not contain other rust inhibitors, In the thickener, the mole number of the aliphatic monoamine is greater than the mole number of the alicyclic monoamine.

5. A rolling bearing comprising an inner ring, an outer ring, a plurality of rolling elements interposed between the inner ring and the outer ring, sealing members provided at openings at both axial ends of the inner ring and the outer ring, and a grease composition sealed in a bearing space, It is characterized in that The grease composition is the grease composition according to claim 1.

6. The rolling bearing according to claim 5, characterized in that: The cage is made of polyamide resin.

7. The rolling bearing according to claim 5, characterized in that: The sealing member is a non-contact type sealing member that is fixed to one of the inner ring and the outer ring and faces the other member with a gap therebetween.

8. The rolling bearing according to claim 5, characterized in that: The rolling bearing is subjected to a high temperature condition of 100°C to 150°C and a dm·n value of 50×10 4 ~180×10 4 Used under high-speed conditions.

9. The rolling bearing according to claim 5, characterized in that: It is a bearing for engine.

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