JPH08294246A - Electric rotating machine - Google Patents

Abstract

PURPOSE: To provide an electric rotating machine equipped with a roller bearing using high-speed long-life grease composition where lubrication and oxidation stability are improved. CONSTITUTION: This is an electric rotating machine using, for a roller bearing, a oxidation-resistant composition, which contains lithium soap where mixed oxidation inhibitor where dialkyl dithiocarbamic acid chlorine compound and aromatic amine compound are combined at a weight ratio of 90:10-10:90 with the base oil where polyole ester oil and alkyl phenyl ether oil are mixed at a weight ratio of 80:20-20:80 is added by 0.2-5wt.%, lithium complex soup, and a diurea compound, as thickening agents.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rolling bearing used for high-speed rotation with a large diameter or an electric rotating machine for high-speed rotation using a rolling bearing made of ceramic in a part or all of the bearing structure. .

[0002]

2. Description of the Related Art The replacement period or life of rolling bearings used for mechanical parts, electric motors, etc. is greatly affected by the performance of lubricating grease filled in the rolling bearings. Lubricating grease used in such operating parts of machine parts and electric rotating machines includes metal soaps such as lithium soap and lithium complex soap as thickeners, urea compounds such as diurea, mineral oils as base oils, and the like. , Synthetic oils such as poly-α-olefin oil, polyol ester, and polyphenyl ether are used, and further, amine-based and phenol-based antioxidants and rust preventives for improving the properties of lubricating grease,
Further, depending on the application, a mixture of various additives such as extreme pressure agent is used. In particular, the antioxidant is an essential additive for improving the thermal oxidation stability of the lubricating grease, and is added to most lubricating greases. Specifically, an amine-based antioxidant represented by phenyl-α-naphthylamine, 4,4-methylenebis (2,6-di-t).
-Phenolic antioxidant represented by butylphenol) is used. It is known that the effect of adding an antioxidant or a rust preventive agent varies greatly depending on the type of thickener and base oil, rolling bearing material, operating temperature, bearing type, bearing size, operating conditions, etc.

In recent years, with the reduction in size and weight of various devices and electric rotating machines, and the speeding up, lubricating grease has been used under severe conditions such as high temperature, high load and high speed, and the demand for maintenance-free has become stronger. There is. In particular, inverter-controlled and chopper-controlled high-speed rotating traction motors have been widely adopted in order to respond to higher vehicle speeds. Therefore, the main motor does not require maintenance such as brushes and commutators, and only the rolling bearing is targeted for maintenance, and a maintenance-free and highly reliable main motor is demanded. Maintenance of the main motor is greatly affected by the performance of the lubricating grease used for the rolling bearings, so that there is a strong demand for so-called long-life grease with a long grease replacement period. On the other hand, the rolling bearing of the vehicle main motor has a large bore of 50 mm or more and an allowable rotational speed dmN value of grease lubrication of 40 to 45 × 10 ⁴ [pitch circle diameter dm (mm) of rolling bearing, rotational speed N ( The maintenance interval must be shortened because it is used at high speeds and load conditions that greatly exceed [rpm)], and high-speed traction motors with longer-life grease that support high-speed rotation are strongly desired.

[0004]

As described above, the rotation speed of the electric motor is much higher than the permissible rotation speed of grease lubrication, so that the bearing temperature is high and the bearing temperature is high because it is used under high load conditions. No such lubricating grease is satisfactory in terms of oxidation stability and lubricating life, and the maintenance interval of the motor becomes short. When the lubricating grease is oxidized and deteriorated, properties such as dropping point, shear stability, consistency, and oil separation characteristics change significantly, and the grease leaks from the bearing and the life is extremely shortened. Furthermore, when the base oil, which plays a major role in lubrication, deteriorates due to oxidation, the amount of base oil decreases due to an increase in the amount of evaporation, sludge formation,
Not only the lubrication function is lost due to increase in viscosity, but also the organic acid generated by oxidative deterioration causes corrosion of the bearing. Therefore, in order to promote maintenance-free electric motors, it is naturally important to suppress the oxidative deterioration of the lubricating grease, but it does not soften and the grease itself does not leak from the bearings, and the fluidity of the lubricating grease in the bearings is reduced. It is an important issue to maintain and supply the base oil sufficiently to the bearing lubrication part. To improve these, JP-A 1-2
Lubrication grease using a diurea compound whose terminal group described in JP-A-59097 is mainly an aromatic group and an alkyldiphenyl ether as a base oil is effective, but a lubricating grease using this thickener is The fluidity of grease in the bearing is inferior, and under high-speed conditions there is a problem that the bearing may seize early in rolling bearings of relatively large diameter due to insufficient flow of lubricating grease to the bearing lubrication part and insufficient supply of base oil. . In order to improve the flowability of the lubricating grease to the lubrication part and the rust preventive property, in JP-A-5-98280, alkyl diphenyl ether is an essential component,
And a grease composition containing a base oil having a kinematic viscosity at 40 ° C. of 90 to 160 mm ² / s and a diurea compound having a proportion of aromatic hydrocarbons in the end groups of 70 to 95 mol% as a thickener, and its blending. A grease comprising an organic sulfonate, a nitrite, and a nonionic surfactant having an HLB of 1.5 to 9 as a rust preventive additive is disclosed. In addition, in Japanese Unexamined Patent Publication No. 5-140576, in order to improve high temperature durability, noise generation at low temperature start, and rust prevention,
A grease is disclosed in which an aliphatic diurea compound is mixed with an α-olefin and an alkyl diphenyl ether as a mixed base oil, and barium sulfonate is mixed as an antirust additive.
Regarding lithium grease, JP-A-63-162791,
Japanese Patent Laid-Open No. 5-86392 discloses improvement in oxidation resistance and life characteristics at high temperatures. These inventions
In either case, a small bearing having a bearing inner diameter of 20 to 30 mm or less can be expected to have a considerably long life. However, in a large-diameter bearing having an inner diameter of 50 mm or more as used in an electric motor of a vehicle or the like, and at high speed rotation, the lubrication grease does not sufficiently move to the lubrication part due to insufficient fluidity of the lubrication grease. Also, due to the large amount of scatter due to centrifugal force, insufficient lubrication causes insufficient lubrication and increased evaporation loss, leading to early lubrication failure, which requires a great deal of labor and time to remove the main motor from the vehicle and replace the bearings. There was a problem to say.

Therefore, an object of the present invention is to provide a bearing inner diameter of 5
In rolling bearings with a large diameter of 0 mm or more, in an electric rotating machine used under the conditions of high speed and load with an allowable rotational speed of grease lubrication dmN value of 40 to 45 × 10 ⁴ , the fluidity of lubricating grease and the base oil to the lubrication part An object of the present invention is to provide a long-term maintenance-free electric motor for a vehicle by using a lubricating grease having good supplyability, excellent oil film forming ability, small evaporation loss, and excellent oxidation resistance.

[0006]

[Means for Solving the Problems] As a result of intensive studies on extending the life of the lubricating grease in order to achieve long-term maintenance-free maintenance of the main motor that rotates at high speed in a large diameter bearing having a bearing inner diameter of 50 mm or more such as a vehicle. By adding a mixed antioxidant that is a combination of two specific antioxidants to a base oil that is a blend of two specific synthetic oils, a long-life grease with excellent oxidation stability and lubricity at high temperatures can be obtained. The inventors have found that they can be obtained and arrived at the present invention.

A first point of the present invention is to use two types of synthetic oils having different chemical structures as base oils for the rolling oils of rolling bearings of electric rotating machines. One of synthetic base oils is a polyol ester synthesized from a polyhydric alcohol having a carbon skeleton of neopentane and a fatty acid having 5 to 18 carbon atoms, or an aliphatic monocarboxylic acid having 4 to 10 carbon atoms and an aliphatic dicarboxylic acid. Mixed acid of acids and trimethylolethane,
It is a complex type polyol ester consisting of polyhydric alcohols of trimethylolpropane, pentaerythritol and dipentaerythritol. Specific examples of the fatty acid include butyric acid, valeric acid, hexanoic acid, heptanoic acid, octanoic acid, 2-ethylhexanoic acid, isooctanoic acid, nonanoic acid, isononanoic acid, decanoic acid, isodecanoic acid, stearic acid and the like. Specific examples of the polyhydric alcohol include trimethylolethane, trimethylolpropane, pentaerythritol, dipentaerythritol and the like.

Another synthetic oil has 10 carbon atoms as a substituent.
22 is an alkyl phenyl ether oil of an alkyl diphenyl ether or an alkyl polyphenyl ether. The properties of the alkyl diphenyl ether or the alkyl polyphenyl ether differ depending on the number of carbon atoms of the substituent and the number of added moles. The polyol ester or complex-type polyol ester and the alkyl phenyl ether used in the electric rotating machine bearing of the present invention are 80 to 20:
It is a mixed base oil contained in a weight ratio of 20-80. The content of the mixed base oil with respect to the total amount of grease is not particularly limited, but it is 80 in order to achieve maintenance-free long-term operation of an electric rotating machine used under high speed conditions.
~ 90 wt% is preferred.

A second important point of the present invention is the blending of the lubricating oil of the rolling bearing of the electric rotating machine with an antioxidant having a different effect of preventing oxidation deterioration. As a combination of additives for greatly improving the oxidative stability of lubricating grease, a dialkyldithiocarbamate compound and an aromatic amine-based compound are used.
The lubricating grease contains a mixture having a weight ratio of 0 to 10:10 to 90.

Specific examples of the dialkyldithiocarbamate compound include zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate, zinc dibutyldithiocarbamate, sodium dimethyldithiocarbamate,
Examples include sodium diethyldithiocarbamate, sodium dibutyldithiocarbamate, nickel diethyldithiocarbamate, nickel dibutyldithiocarbamate, copper dimethyldithiocarbamate, iron diethyldithiocarbamate, selenium diethyldithiocarbamate, terium diethyldithiocarbamate, and zinc butylxanthate.

Specific examples of aromatic amine compounds include:
Phenyl-α-naphthylamine, alkylated phenyl-
Alkylated diphenylamines to which α-naphthylamine, butyl group, octyl group, nonyl group, etc. have been added, N, N'-
Di-2-naphthyl-p-phenylenediamine, N, N '
-Diphenyl-p-phenylenediamine and the like are exemplified.

The mixed antioxidant is preferably added in an amount of 0.2 to 5% by weight based on the total amount of lubricating grease. When the addition amount is less than 0.2% by weight, the improvement in the oxidation resistance is insignificant.
Even if it exceeds, the oxidation resistance does not improve so much.

The dialkyldithiocarbamate compound may cause corrosion or discoloration of copper or a copper alloy material depending on use conditions. When used in the coexistence of such materials, it is desirable to add an additive for preventing corrosion as necessary. Benzotriazole and benzotriazole compounds are effective as corrosion inhibitors, and the compounding amount thereof is preferably 0.01 to 2% by weight based on the total amount of grease.

The thickener used in the present invention is a known lithium soap, lithium complex soap and diurea compound. The thickener and its blending amount should be arbitrarily selected according to the usage conditions of the lubricating grease, but for electric rotating machine bearings that use large diameter bearings under high speed conditions, 10 to 20% by weight or NLGI consistency N
o.2 is preferable.

Further, a rust preventive agent, an oiliness agent, an extreme pressure agent, a solid lubricant and the like can be added to the lubricating grease, if necessary, depending on the usage conditions of the electric rotating machine.

The present invention is an electric rotating machine provided with a specific lubricating grease composition. The lubricating oil comprising the mixed base oil and the antioxidant of the present invention used for grease is used for rolling bearings, sliding bearings, etc. It can also be applied to lubrication and can contribute greatly to maintenance-free operation of various devices and equipment.

[0017]

[Operation] The reliability of the electric rotating machine, which has a large bore diameter of 50 mm or more and is subject to high speed and high load conditions, is determined by the lubricating grease with which the bearing is filled. When the base oil of the grease is a mixed base oil in which a polyol ester and an alkyl phenyl ether are blended in a predetermined ratio, it becomes excellent in heat resistance, oxidation stability and lubricity. In addition, by blending a mixed antioxidant in which a dialkyldithiocarbamate compound and an aromatic amine compound are combined, the evaporation loss, viscosity, and total acid value of the mixed base oil can be improved even in the presence of copper and copper alloy materials and iron materials. The change and consumption of the antioxidant are extremely small, and maintenance-free operation of the electric rotating machine can be achieved.

When the bearing diameter is large, the separation characteristic of the mixed base oil separated from the lubricating grease becomes important. The mixed base oil is to continue to supply a suitable amount of base oil with little evaporation loss, oxidative deterioration and viscosity change to the lubrication surface for a long time. For this purpose, the thermal oxidative stability, shear stability and retention of the mixed base oil of the thickener are important. The use of lithium soap, lithium complex soap, and diurea compounds, which are excellent in these properties, and the addition of antioxidants, which are a mixture of dialkyldithiocarbamate compounds and aromatic amine compounds, greatly reduces the oxidation resistance of thickeners. Since the mixed base oil was able to be supplied to the lubrication surface of the rolling bearing for a long period of time, the service life of the lubricating grease was extended, and long-term maintenance-free operation of the electric rotating machine was achieved.

[0019]

The present invention will be described in detail below with reference to Examples and Comparative Examples. The evaluation test method is as follows.

Evaluation test method (1) Evaporation amount test Approximately 20 g of grease was weighed in a glass beaker and a brass dish, and allowed to stand in a constant temperature bath at 150 ° C. to determine the change with time in the amount of evaporation from the weight change before and after heating. It was measured. The amount of evaporation in this test includes evaporation of light components in the base oil and volatile substances produced by oxidative deterioration, but the greater the amount of oxidative deterioration, the more volatile substances are produced, resulting in a larger amount of evaporation.

(2) Measurement of total acid value Glass plate and brass plate (thickness 2 mm x length 50 mm x width 40 m)
m) Apply grease to a thickness of 3 mm and apply this to 150 ° C.
After being left to stand in the constant-temperature bath of No. 3, and subjected to a heat deterioration test, the base oil extracted from the grease was measured for the total acid value by the method of JIS K 2501 to obtain the change before and after the heat deterioration test.

(3) High-speed rotation test with electric rotating machine Grease after the rotation test was taken from the cylindrical roller bearing (NU314) incorporated in the electric rotating machine, and the wear amount (iron content) of the bearing mixed in the grease and the extraction base The total acid number of oil and the consumption of antioxidant were measured. The test conditions are as follows.

Rotational speed: 8,000 rpm Load: 500 kgf Bearing outer ring temperature: 100 ° C. Bearing wear amount in grease (grease iron powder concentration meter: manufactured by Nippon Steel Tube Co., Ltd.): Syringe is filled with grease after rotation test. The iron powder concentration is indirectly measured by detecting the change in the magnetic resistivity of grease as an impedance change in the coil by the electromagnetic induction method.

Amount of consumption of antioxidant: The amount of consumption of the antioxidant was determined by FI-IR measurement from the change in absorbance at a specific wave number of the antioxidant before and after the test.

(Examples 1 to 13 and Comparative Examples 1 to 22) Alkyl phenyl ether oil and polyol ester oil shown in Table 1 were blended in a weight ratio of 50:50 to a mixed base oil (A) as a mixed antioxidant. Nickel dibutyldithiocarbamate dialkyldithiocarbamate compounds (Nocrac NBC: Ouchi Shinko Chemical Co., Ltd.) and (B)
Aromatic amine compound phenyl-α-naphthylamine (Nocrac PA: manufactured by Ouchi Shinko Chemical Co., Ltd.) was added at 50: 5.
It is a mixed base oil composition with 1% by weight of mixed antioxidants combined in a weight ratio of 0. As a comparative example, it is a base oil composition containing 1% by weight of the antioxidant shown in Table 2. Brass was immersed in each base oil composition and the base oil composition as an oxidation catalyst, and the temperature was set to 1200 at a temperature of 150 ° C.
Heated for hours. After the heat deterioration test, the evaporation amount, total acid value, viscosity ratio and precipitates (sludge) were measured to evaluate the effect of adding the antioxidant. Table 3 shows the results of Examples 1 to 13 and Table 4 shows the results of Comparative Examples 1 to 22.

[0026]

[Table 1]

[0027]

[Table 2]

[0028]

[Table 3]

[0029]

[Table 4]

(Examples 14 to 26 and Comparative Examples 23 to 4)
4) A lithium soap grease using the base oil to which the antioxidant shown in Examples 1 to 14 of Table 1 and Comparative Examples 1 to 22 of Table 2 is added. This lithium soap grease was applied to a glass plate and a brass plate and subjected to a heat deterioration test at a temperature of 150 ° C for 1200 hours, a total acid value and a viscosity ratio of the extracted base oil, and a high speed rotation test by an electric motor, and then a cylindrical roller bearing (NU
The grease was sampled from 314), and the wear amount (iron content) of the bearing mixed in the grease, the total acid value of the extracted base oil, and the consumption amount of the antioxidant were measured. The results of Examples 14 to 26 and Comparative Examples 23 to 44 are shown in Table 5.

[0031]

[Table 5]

The lithium soap grease was manufactured by the following method.

Alkyl diphenyl-tel oil total amount 410 g
180 g of stearic acid was added, and the mixture was heated with stirring to a temperature (80 to 90 ° C.) at which it was completely dissolved. At this temperature, a mixture of 28 g of lithium hydroxide and 56 g of hot water was added, and a saponification reaction was carried out at 95 to 100 ° C. for 1 hour while stirring. Next, after heating to about 210 ° C. with stirring and holding for 5 minutes, 410 g of polyol ester oil was added, and the mixture was stirred and cooled. This was used as the base grease.

After taking 891 g of this base grease, adding 9 g of an antioxidant and heating to 100 ° C. with stirring,
The mixture was stirred and cooled to room temperature. Then, with a three-roll mill,
The mixture was kneaded three times to prepare a NLGI consistency grade No. 2 lithium soap grease. (Examples 27 to 39 and Comparative Examples 45 to 49) The lithium complex soap greases used as the base oils of Comparative Examples 45 to 49 shown in Tables 1 and 6.

[0035]

[Table 6]

The lithium complex soap grease was manufactured by the following method.

Alkyl diphenyl ether oil total amount 435
12-Hydroxystearic acid 106.6 g and azelaic acid 23.4 g are added to the mixture, and the mixture is stirred at 80-90.
It melt | dissolved by heating to 0 degreeC. Lithium hydroxide at this temperature 26.
A mixture of 1 g and 52.2 g of hot water was added, and a saponification reaction was carried out at 95 to 100 ° C. for 1 hour while stirring. Next, the mixture was heated to about 210 ° C. with stirring and held for 5 minutes, 435 g of polyol ester oil was added, and the mixture was stirred and cooled. This was used as the base grease.

After taking 891 g of this base grease, adding 9 g of an antioxidant and heating to 100 ° C. with stirring,
The mixture was stirred and cooled to room temperature. Then, with a three-roll mill,
The mixture was kneaded 4 times to prepare a NLGI consistency grade No. 2 lithium complex soap grease. This lithium complex soap grease was tested in the same manner as in Example 14. The results are shown in Table 7.

[0039]

[Table 7]

(Examples 40 to 52 and Comparative Examples 50 to 5)
4) A diurea grease using the same base oil as in Tables 1 and 6.

Diurea grease was produced by the following method.

4,4'-diphenylmethane diisocyanate 78. in 420 g of alkyl diphenyl ether oil.
8 g was added and dissolved by heating to 70 to 75 ° C. with stirring. A mixture of 81.2 g of octylamine dissolved in 420 g of polyol ester oil at 70-75 ° C was added and reacted for 1 hour at 95-100 ° C with stirring. next,
After heating to about 170 ° C. with stirring and holding for 30 minutes, the mixture was stirred and cooled to room temperature. This was used as the base grease.

891 g of this base grease was taken, 9 g of a mixed antioxidant was added, and the mixture was heated to 100 ° C. with stirring and then cooled to room temperature with stirring. Next, the mixture was kneaded 2 to 4 times with a three-roll mill to prepare NLGI consistency grade No. 2 diurea grease. This diurea grease was tested in the same manner as in Example 14. Examples 40-52
The results of Comparative Examples 50 to 54 are shown in Table 8.

[0044]

[Table 8]

(Examples 53 to 79) Monoalkyl tetraphenyl ether (manufactured by Matsumura Laboratory Co., Ltd .: S-310)
1) and pentaerythritol triester (complex type polyol ester, manufactured by CIBA-GEIGY: Rheulube LPE602) at a weight ratio of 50:50 were added to a mixed base oil, and an antioxidant (A) dialkyldithiocarbamate compound and ( B) A lithium complex soap grease was prepared in the same manner as in Example 27 by adding 1% by weight of a mixed antioxidant in which aromatic amine compounds were combined at the mixing ratio shown in Table 9. This grease was applied to a brass plate and subjected to heat deterioration at a temperature of 150 ° C. for 1200 hours. The base oil was extracted from the heat-aged grease and the total acid value and viscosity ratio were measured. The results are also shown in Table 9.

[0046]

[Table 9]

(Example 80) Pentaerythritol tetraester (complex type polyol ester; ADECO Fine Chemical Co., Ltd .: F-Coluve 100Z) and alkyl diphenyl ether (Matsumura Laboratory Co., Ltd.):
A lithium complex soap grease prepared by adding 0.1 to 6 wt% of a mixed base oil in which Molesco Highlube LB-100) was blended in a weight ratio of 50:50 and a mixed antioxidant in a mixing ratio shown in Table 10 was prepared. This grease was applied to a brass plate in a thickness of 2 mm and subjected to heat deterioration at a temperature of 150 ° C. for 1200 hours. The mixed base oil was extracted from the heat-aged grease and the total acid value and viscosity ratio were measured. The results are also shown in Table 10.

[0048]

[Table 10]

(Examples 81 to 92) Trimethylolpropane tricaprylate (Reolub LT3000), pentaerythritol tetraheptanoate (Reolubu LP2800) and pentaerythritol tetraester (complex type polyol ester oil; manufactured by ADEKA Fine Chemical Co., Ltd.):
F-Coluve 100Z) and alkyl diphenyl ether (Matsumura Laboratory Co., Ltd .: Moresco Highlube LB-1)
No. 00) is shown in Table 11 and mixed antioxidant (A) nickel dibutyldithiocarbamate as a dialkyldithiocarbamate compound and (B) alkylated phenyl-α-naphthylamine as an aromatic amine compound as 50:50. A lithium soap grease was obtained in the same manner as in Example 13 except that 1% by weight of the base oil was added. This grease was applied to a brass plate and subjected to heat deterioration at a temperature of 150 ° C. for 1200 hours. Lubricating base oil was extracted from the heat-aged grease and the total acid value and viscosity ratio were measured. The results are also shown in Table 11.

[0050]

[Table 11]

As is apparent from the examples, mixed antioxidants in which (A) an alkyldithiocarbamate compound and (B) an aromatic amine compound are combined with a mixed base oil containing a polyol ester oil and an alkylphenyl ether oil are mixed. The base oil added with the agent, and the grease using the above-mentioned base oil, the lithium soap, the lithium complex soap, and the diurea compound as a thickener, have a higher evaporation amount than the lubricating oil and the grease of Comparative Example even at high temperature. Excellent in thermal oxidation stability with little change in total acid value and viscosity ratio. In addition, even in a high-speed test with an electric rotating machine, the total acid value, the amount of antioxidant consumption, the amount of bearing wear, etc. are extremely small, and the maintenance-free period of the electric rotating machine can be greatly extended.

[0052]

As is clear from the above examples, the electric motor using the base oil composition and the lubricating grease composition of the present invention can be used under high temperature and high speed use conditions which cannot be handled by the electric motor using the conventional grease. Can be maintenance-free.

Claims (3)

[Claims] 1. An electric rotating machine equipped with a rolling bearing, wherein the bearing comprises a grease composition containing a mixed oil of a polyol ester and an alkylphenyl ether, a mixture of an alkyldithiocarbamate salt and an aromatic amine compound, and lithium soap. An electric rotating machine using a grease composition containing one of a lithium complex soap and a diurea compound. 2. The grease composition according to claim 1, wherein the mixed oil is a polyol ester synthesized from a linear or branched fatty acid having 5 to 18 carbon atoms and trimethylolpropane, pentaerythritol and dipentaerythritol, or 1 A complex type polyol ester synthesized from a mixed acid of a basic acid and a dibasic acid, trimethylolpropane, pentaerythritol, and dipentaerythritol, and an alkyl diphenyl ether oil or alkyl polyphenyl ether having 6 to 22 carbon atoms as a substituent Two
An electric rotating machine characterized by using a grease composition contained in a weight ratio of 0:20 to 80. 3. The dialkyldithiocarbamate salt according to claim 1, wherein the aromatic amine compound is 90 to 10:10.
An electric rotating machine comprising: a grease composition containing a mixture blended in a weight ratio of 90 to 90% by weight based on the total weight of the grease composition.