Grease composition for constant velocity joints

Abstract

The present invention provides a grease composition for constant-velocity joints which comprises (a) a base oil, (b) a diurea-based thickening agent, (c) molybdenum dithiocarbamate, (d) molybdenum dithiophosphate, (e) a perbasic calcium sulfonate, and (f) a neutral zinc sulfonate. This composition is excellent in terms of high-temperature durability and vibration diminution.

Description

[Technical Field]

[0001] The present invention relates to a grease composition for a constant velocity joint. [Background technology]

[0002] In the automobile industry, front-wheel drive (FF) vehicles have become widespread due to their lightweight design and increased interior space, which are key environmental measures (CO2 reduction). Constant velocity joints (CVJs), which are essential for power transmission in FF vehicles, are widely used. Among these CVJ types, the plunging type constant velocity joint rotates at an angle, causing the parts inside the joint to perform a complex rolling and sliding motion. When this happens, friction between the internal parts creates sliding resistance in the axial direction, and if this resistance is large, it can cause vibration and noise. As automobile engines have become more powerful in recent years, the lubrication conditions inside constant velocity joints have shifted to higher surface pressure. The higher the surface pressure under lubrication conditions, the more likely wear occurs inside the constant velocity joint, which can lead to problems such as reduced durability (flaking resistance) and increased vibration. Furthermore, such constant velocity joints are also required to have durability at high temperatures.

[0003] As greases with excellent vibration suppression performance, greases for constant velocity joints have been proposed that are made by combining urea grease with additives of molybdenum dithiocarbamate and molybdenum dithiophosphate, or by mixing these organic molybdenum compounds with zinc dithiophosphate (see Patent Document 1), as well as grease compositions for constant velocity joints that contain base oil, a urea-based thickener, molybdenum dithiocarbamate, calcium sulfonate, and thiophosphate. (See Patent Document 2) Furthermore, in response to the recent demand for even quieter operation, a grease composition for constant velocity joints has been proposed in which a grease composed of a base oil and a urea-based compound thickener is mixed with at least one of molybdenum dialkyldithiocarbamate, molybdenum dialkyldithiophosphate, or molybdenum diaryldithiophosphate, and an ashless dithiocarbamate or zinc dithiocarbamate (see Patent Document 3), and a composition for constant velocity joints containing a base oil, a diurea-based thickener, molybdenum sulfide dialkyldithiocarbamate, zinc sulfonate, a sulfur-phosphorus-based extreme pressure agent, and vegetable oil (see Patent Document 4). As a grease that also takes durability into consideration, a composition for constant velocity joints containing a base oil, a thickener, montan wax, zinc sulfonate, and molybdenum sulfide dialkyldithiocarbamate has been proposed (see Patent Document 5). As described above, conventional grease compositions for constant velocity joints have demonstrated excellent performance in terms of vibration suppression, and their durability has also been studied at room temperature. However, it cannot be said that sufficient research has been conducted into the issue of durability at high temperatures. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 5-79280 [Patent Document 2] Japanese Patent Publication No. 11-172276 [Patent Document 3] Patent Publication No. 2009-235416 [Patent Document 4] Patent Publication No. 2011-37950 [Patent Document 5] International Publication No. 2014 / 0954797 Summary of the Invention [Problem to be solved by the invention]

[0005] Therefore, an object of the present invention is to provide a grease composition that has excellent durability and vibration damping properties even at high temperatures. [Means for solving the problem]

[0006] 1.(a) Base oil (b) Diurea-based thickener (c) Molybdenum dithiocarbamate (d) Molybdenum dithiophosphate (e) Overbased calcium sulfonate (f) Neutral zinc sulfonate A grease composition for a constant velocity joint, comprising: 2. The grease composition according to claim 1, wherein the content of component (f) is 0.1 to 10 mass % based on the total mass of the composition. 3. The grease composition according to claim 1 or 2, wherein the content of component (f) is 0.5 to 5 mass % based on the total mass of the composition. 4. The grease composition according to any one of claims 1 to 3, wherein the content of component (f) is 0.8 to 3 mass % based on the total mass of the composition. 5. The grease composition according to any one of claims 1 to 4, wherein the content of component (e) is 0.1 to 10 mass % based on the total mass of the composition. 6. The grease composition according to any one of claims 1 to 5, wherein the content of component (e) is 0.2 to 5 mass % based on the total mass of the composition. 7. The grease composition according to any one of claims 1 to 6, wherein the content of component (e) is 1.2 to 3.5 mass % based on the total mass of the composition. 8. The grease composition according to any one of claims 1 to 7, wherein component (b) is an aliphatic diurea thickener. 9. A constant velocity joint in which the grease composition according to any one of claims 1 to 8 is packed. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a grease composition that has excellent durability even at high temperatures and also has excellent vibration suppression properties. DETAILED DESCRIPTION OF THE INVENTION

[0008] (a) Base oil The base oil that can be used in the composition of the present invention is not particularly limited, and mineral oil and / or synthetic oil can be used. Examples of synthetic oils include synthetic hydrocarbon oils such as poly-α-olefins; phenyl ether oils such as pentaphenyl ether, tetraphenyl ether, monoalkyl tetraphenyl ether, dialkyl tetraphenyl ether, and alkyl diphenyl ether oil; alkylbenzene oil; ester oils such as monoester oil, diester oil, polyol ester oil, and aromatic ester oil; polyglycol oil; silicone oil; fluorine oil; and ionic liquids. In the present invention, it is preferable to use a mineral oil as the base oil from the viewpoint of cost. A base oil containing a mineral oil as the main component and a synthetic oil mixed therewith may also be used. When the base oil of the present invention is a mixed oil of mineral oil and synthetic oil, the mineral oil preferably accounts for 50 to 100 mass %, more preferably 70 to 100 mass %, and even more preferably 90 to 100 mass %, based on the total mass of the base oil. The kinematic viscosity of the base oil of the present invention at 100°C is preferably 5 to 30 mm 2 / s, more preferably 7 to 20 mm 2 / s. 5mm 2 If the oil film is not formed in the constant velocity joint at less than 30mm / s, the durability tends to be insufficient. 2 If the CVJ temperature exceeds 1 / s, the durability of the CVJ will tend to decrease due to heat generation. From the viewpoint of flowability, the content of the base oil is preferably 50 to 100 mass %, more preferably 70 to 100 mass %, and even more preferably 80 to 100 mass %, based on the total mass of the composition.

[0009] (b) Diurea-based thickener The diurea thickener that can be used in the present invention is represented by the following formula (1). R 1 -NHCONH-R 2 -NHCONH-R 3 (1) In the formula, R 2 is a divalent aromatic hydrocarbon group having 6 to 15 carbon atoms, and R 2 As R, tolylene diisocyanate or diphenylmethane diisocyanate is preferred, and diphenylmethane diisocyanate is more preferred. 1 and R 3 may be the same or different and are a linear or branched alkyl group having 6 to 30 carbon atoms, an aryl group having 6 or 7 carbon atoms, or a cyclohexyl group. The diurea compound of formula (1) includes R 1 and R 3 Preferably, the aliphatic diurea compound is one in which all of the above are alkyl groups having a carbon number of 6 to 30. The aliphatic diurea compound can be obtained by reacting a diisocyanate with an aliphatic monoamine.

[0010] The diurea compounds of formula (1) also include R 1 and R 3 and the other is a cyclohexyl group. The alicyclic aliphatic diurea compound is obtained by reacting a diisocyanate with an alicyclic monoamine and an aliphatic monoamine, and is therefore actually a mixture containing an alicyclic aliphatic diurea compound, an aliphatic diurea compound, and an alicyclic diurea compound. R 1 and R 3When either of the groups is a cyclohexyl group, the other is preferably a linear alkyl group having 8 or 18 carbon atoms. In this case, the ratio of cyclohexyl groups to the total of cyclohexyl groups and alkyl groups is preferably 70 to 100 mol %, more preferably 80 to 100 mol %, from the viewpoint of fluidity.

[0011] As the thickener of the present invention, an aliphatic diurea compound is preferred from the viewpoint of durability. In particular, in formula (1), R 1 and R 3 and R 2 A diurea compound in which is diphenylmethane diisocyanate is preferred. In particular, in formula (1), R 1 and R 3 is a linear alkyl group having 8 or 18 carbon atoms, and a diurea compound in which R2 is diphenylmethane diisocyanate is preferred.

[0012] The penetration of the grease composition of the present invention is preferably 250 to 400, more preferably 280 to 370, and even more preferably 310 to 340. In this specification, the term "penetration" refers to 60-stroke worked penetration. The penetration can be measured in accordance with JIS K2220 7. The content of the thickener is preferably 10% by mass or less, more preferably 5 to 10% by mass, and even more preferably 6 to 7% by mass, based on the total mass of the composition, so that the consistency of the grease composition can be set within the above range.

[0013] (c) Molybdenum dithiocarbamate (MoDTC) The molybdenum dithiocarbamate usable in the present invention is a general term for organometallic load-bearing additives whose metal group is molybdenum, and is generally widely used as an extreme pressure additive. A preferred example of the molybdenum dithiocarbamate can be represented by the following formula (2): [R 4 R 5N-CS-S]2-Mo2O m S n (2) In the formula, R 4 and R 5 may be the same or different and each independently represents a linear or branched alkyl group having 1 to 24 carbon atoms, preferably 3 to 18 carbon atoms, m is 0 to 3, n is 4 or 1, and m+n=4. Molybdenum dithiocarbamates include oil-soluble molybdenum dithiocarbamates (i.e., liquid at room temperature (about 25°C)) and oil-insoluble molybdenum dithiocarbamates (i.e., solid at room temperature). Either type can be used as the molybdenum dithiocarbamate in the present invention, but a combination of an oil-soluble molybdenum dithiocarbamate and an oil-insoluble molybdenum dithiocarbamate is preferred because it provides excellent durability and suppresses heat generation and vibration in the CVJ. From the viewpoint of vibration suppression, the content of component (b) in the grease composition of the present invention is preferably 0.1 to 10 mass%, more preferably 0.5 to 5 mass%, and even more preferably 1 to 3 mass%, based on the total mass of the composition. When an oil-soluble molybdenum dithiocarbamate and an oil-insoluble molybdenum dithiocarbamate are contained, the mass ratio of the oil-soluble molybdenum dithiocarbamate to the oil-insoluble molybdenum dithiocarbamate is preferably 4:6 to 10:0, more preferably 6:4 to 8:2, as this provides excellent vibration suppression.

[0014] (d) Molybdenum dithiophosphate (MoDTP) A preferred example of the molybdenum dithiophosphate used in the present invention is one represented by the following formula (3): [(R 6 O)(R 7 O)PS-S]2Mo2O m S n (In the formula, R 6 and R 7 are each independently an alkyl group having 1 to 24 carbon atoms or an aryl group having 6 to 30 carbon atoms, m is 0 to 3, n is 4 or 1, and m+n=4. From the viewpoint of durability, the content of component (d) in the grease composition of the present invention is preferably 0.1 mass % or more, more preferably 0.1 to 5 mass %, and even more preferably 0.2 to 2 mass %, based on the total mass of the composition.

[0015] (e) Overbased calcium sulfonate The overbased calcium sulfonate used in the present invention has a base number of 200 mgKOH / g or more. From the viewpoint of durability, the base number is preferably 300 mgKOH / g or more, and more preferably 300 to 500 mgKOH / g. In the present invention, the base number is a value measured in accordance with JIS K 2501. Component (e) can be a calcium salt of a sulfonic acid having an organic group as a lipophilic group. Examples of such organic sulfonic acids include petroleum sulfonic acids obtained by sulfonating aromatic hydrocarbon components in lubricating oil fractions, and synthetic sulfonic acids such as dinonylnaphthalene sulfonic acid and heavy alkylbenzene sulfonic acid. Component (e) is preferably calcium sulfonate, which is overbased with calcium carbonate. Calcium alkylaromatic sulfonates containing calcium carbonate are particularly preferred. From the viewpoint of durability, the content of component (e) in the grease composition of the present invention is preferably 0.1 to 10 mass %, more preferably 0.2 to 5 mass %, and even more preferably 1.2 to 3.5 mass %, based on the total mass of the composition.

[0016] (f) Neutral zinc sulfonate The neutral zinc sulfonate used in the present invention has a base number of 10 mgKOH / g or less. The sulfonic acid constituting the zinc sulfonate is the same as that described for component (e). As the neutral zinc sulfonate, zinc dinonylnaphthalene sulfonate is preferred. From the viewpoint of durability, the content of the neutral zinc sulfonate in the grease composition of the present invention is preferably 0.1 to 10 mass %, more preferably 0.5 to 5 mass %, and even more preferably 0.8 to 3 mass %, based on the total mass of the composition.

[0017] The total amount of component (e) and component (f) is preferably 0.5 to 5 mass %, more preferably 1 to 3 mass %, based on the total mass of the composition, as this provides excellent heat resistance. A mass ratio of component (e) to component (f) of (e):(f)=9:1 to 1:9 is preferred because of excellent durability. A mass ratio of (e):(f)=8:2 to 3:7 is more preferred, and a mass ratio of (e):(f)=7:3 to 4:6 is even more preferred. In particular, a mass ratio of component (e) to component (f) of (e):(f)=7:3 to 4:6 is preferred because of excellent durability and heat resistance.

[0018] The grease composition of the present invention may contain additives that are commonly used in greases, as needed. The content of these additives is usually 0.1 to 5 mass %, preferably 0.5 to 3 mass %, based on the total amount of the grease composition. Examples of such additives include antioxidants such as amines, phenols, quinolines, sulfurs, and zinc dithiophosphates; rust inhibitors such as zinc-based, carboxylic acid-based, carboxylate-based (particularly dibasic acid salts such as sodium sebacate, sodium azelaate, and sodium suberate), and amine-based; anti-wear agents such as sulfurized oils and fats, sulfurized olefins, phosphate esters, phosphites, and acidic phosphate amine salts; oiliness agents such as fatty acids, fatty acid esters, and phosphate esters; and solid lubricants such as graphite, polytetrafluoroethylene (PTFE), and zinc oxide. From the viewpoint of heat resistance, it is preferable to contain an antioxidant. The antioxidant is preferably an amine-based antioxidant, more preferably an alkyldiphenylamine. The content of the antioxidant is preferably 0.1% by mass or more, more preferably 0.1 to 2% by mass, and even more preferably 0.2 to 1% by mass, based on the total mass of the composition.

[0019] The composition of the present invention includes: (a) Base oil (b) Diurea-based thickener (c) Molybdenum dithiocarbamate (d) Molybdenum dithiophosphate (e) Overbased calcium sulfonate (f) Neutral zinc sulfonate (g) antioxidants It is preferable that the material consists of only In this case, the content of each component is preferably 80 to 100 mass% for (a), 6 to 7 mass% for (b), 1 to 3 mass% for (c), 0.2 to 2 mass% for (d), 0.5 to 3 mass% for (e), 0.8 to 3 mass% for (f), and 0.2 to 1 mass% for (g), based on the total mass of the composition.

[0020] The composition of the present invention also includes (a) Base oil (b) Aliphatic diurea thickener (c) Molybdenum dithiocarbamate (d) Molybdenum dithiophosphate (e) Overbased calcium sulfonates containing calcium carbonate with a base number of 300 mg KOH / g or more (f) Neutral zinc sulfonate (g) Amine antioxidants It is preferred that the compound contains: In this case, the content of each component is preferably 80 to 100 mass% for (a), 6 to 7 mass% for (b), 1 to 3 mass% for (c), 0.2 to 2 mass% for (d), 0.5 to 3 mass% for (e), 0.8 to 3 mass% for (f), and 0.2 to 1 mass% for (g), based on the total mass of the composition.

[0021] The composition of the present invention also includes (a) Base oil (b) In the formula (1), R 1 and R 3 and R 2 Aliphatic diurea thickener in which diphenylmethane diisocyanate is used (c) A mixture of an oil-soluble molybdenum dithiocarbamate and an oil-insoluble molybdenum dithiocarbamate. (d) Molybdenum dithiophosphate (e) Calcium alkyl aromatic sulfonate containing calcium carbonate and having a base number of 300 to 500 mg KOH / g (f) Zinc dinonylnaphthalene sulfonate with a base number of 10 mg KOH / g or less (g) Alkyldiphenylamines It is preferred that the compound contains: In this case, the content of each component is preferably 80 to 100 mass% for (a), 6 to 7 mass% for (b), 1 to 3 mass% for (c), 0.2 to 2 mass% for (d), 0.5 to 3 mass% for (e), 0.8 to 3 mass% for (f), and 0.2 to 1 mass% for (g), based on the total mass of the composition.

[0022] The grease composition of the present invention is applied to constant velocity joints, and is particularly preferably applied to plunging type constant velocity joints, particularly tripod type constant velocity joints and double offset type constant velocity joints, and particularly to inboard side constant velocity joints, because it provides excellent durability and vibration suppression. [Example]

[0023] [1] Production of grease compositions of Examples 1 to 7 and Comparative Examples 1 to 4 One mole of 4',4-diphenylmethane diisocyanate and two moles of octylamine were reacted in a base oil, the mixture was heated and cooled, and then additives were added in the proportions shown in Table 1 or Table 2 and kneaded in a three-roll mill to produce a grease composition with a worked penetration of 315. Unless otherwise specified, the values ​​in Tables 1 and 2 represent mass % based on the total mass of the grease composition. [2] Preparation of grease composition of Comparative Example 5 A grease composition of Comparative Example 5 was prepared in accordance with the description of Example C4 of Japanese Patent No. 6470851.

[0024] The components used in preparing the grease composition are as follows: <Base oil> Mineral oil (kinematic viscosity at 100°C: 12.4 mm 2 / s) Mineral oil + synthetic oil: Poly-α-olefin (kinematic viscosity at 100°C: 12.0 mm 2 / s) <Additives> MoDTC (oil-insoluble): Molybdenum dithiocarbamate (ADEKA Sakuralube 600, manufactured by ADEKA) MoDTC (oil-insoluble): molybdenum dithiocarbamate (Molyvan A, manufactured by Vanderbilt, used in Comparative Example 5) MoDTC (oil-soluble): Molybdenum dithiocarbamate (ADEKA Sakuralube 525, manufactured by ADEKA) MoDTP: Molybdenum dithiophosphate (ADEKA Sakuralube 300, manufactured by ADEKA) MoDTP: molybdenum dithiophosphate (Molyvan L, manufactured by Vanderbilt, used in Comparative Example 5) Calcium sulfonate (overbased): calcium salt of alkyl aromatic sulfonic acid (LUBRIZOL 5283C, manufactured by The Lubrizol Corporation, base number 375 mg KOH / g) Zn sulfonate (neutral): Zinc dinonylnaphthalene sulfonate (NA-SUL ZS, manufactured by KING INDUSTRIES, base number 5 mg KOH / g) Antioxidants

[0025] [2] Durability evaluation (1) SRV test (high load) [Test conditions] Test speed: 11.9 mm / s (frequency: 3.3 Hz, stroke: 1.8 mm) Test temperature: 90℃ Load: 5.5GPa Test specimen: ball (diameter 17.5 mm, SUJ-2) / plate (SUJ-2, surface roughness Rz 0.5 μm) [Evaluation criteria] ◎ (Pass): Friction coefficient 0.08 or less 〇 (pass): Friction coefficient over 0.08, 0.10 or less △ (pass): Friction coefficient over 0.10, 0.12 or less × (Fail): Seizure occurs or friction coefficient exceeds 0.12

[0026] (2) SRV test (low load) [Test conditions] Test speed: 2.0 mm / s (frequency: 3.3 Hz, stroke: 0.3 mm) Test temperature: 95℃ Load: 2.1 GPa Test specimen: ball (diameter 17.5 mm, SUJ-2) / plate (SUJ-2, surface roughness Rz 5 μm) [Evaluation criteria] 〇 (pass): Friction coefficient 0.10 or less △ (pass): Friction coefficient over 0.10, 0.14 or less × (Fail): Seizure occurs or friction coefficient exceeds 0.14

[0027] [2] Evaluation of vibration suppression (1) TE77 Study The TE77 testing machine is a vibration friction and wear testing machine that operates under sliding conditions. It has been reported that there is a relationship between vibrations generated by a constant velocity joint as a vibration source and the friction coefficient measured under vibration conditions using the TE77 testing machine (Japanese Patent Application Laid-Open Publication No. 2010-065194). Therefore, the TE77 testing machine was used to evaluate vibration suppression in constant velocity joints. [Test conditions] Test speed: 16 mm / s (frequency: 10 Hz, stroke: 0.8 mm) Test temperature: 40℃ Load: 1.2GPa Test specimen: ball (diameter 17.5 mm, SUJ-2) / plate (SCM) [Evaluation criteria] 〇 (pass): Friction coefficient 0.07 or less △ (pass): Friction coefficient over 0.07, 0.10 or less × (fail): Friction coefficient over 0.10

[0028] [comprehensive evaluation] 〇 (Pass): Passed all of the above tests × (Fail): One or more of the above test results failed The results are shown in Tables 1 and 2.

[0029] [Table 1]

[0030] [Table 2]

Claims

1. (a) Base oil (b) Diurea-based thickener (c) Molybdenum dithiocarbamate (d) molybdenum dithiophosphate (e) Overbased calcium sulfonate (f) Neutral zinc sulfonate Including, component (c) comprises an oil-soluble molybdenum dithiocarbamate that is a liquid at 25°C and an oil-insoluble molybdenum dithiocarbamate that is a solid at 25°C; The content of component (e) is 1.2 to 3.5% by mass, based on the total mass of the composition; A grease composition for constant velocity joints, wherein the mass ratio of component (e) to component (f) is (e):(f)=7:3 to 1.1:1.

0.

2. 2. The grease composition according to claim 1, wherein the content of component (f) is 0.1 to 10 mass % based on the total mass of the composition.

3. 3. The grease composition according to claim 1, wherein the content of component (f) is 0.5 to 5 mass % based on the total mass of the composition.

4. 4. The grease composition according to claim 1, wherein the content of component (f) is 0.8 to 3 mass % based on the total mass of the composition.

5. 5. The grease composition according to claim 1, wherein the mass ratio of the oil-soluble molybdenum dithiocarbamate to the oil-insoluble molybdenum dithiocarbamate is from 6:4 to 8:

2.

6. 6. The grease composition according to claim 1, wherein component (b) is an aliphatic diurea thickener.

7. 7. The grease composition according to claim 1, wherein component (b) is an aliphatic diurea compound represented by formula (1). R 1 -NHGNH-R 2 -NHGNH-R 3 (1) (In the formula, R 2 is a divalent aromatic hydrocarbon group having 6 to 15 carbon atoms, and R 1 and R 3 may be the same or different and are linear or branched alkyl groups having 6 to 30 carbon atoms.

8. (a) Base oil (b) Diurea-based thickener (c) Molybdenum dithiocarbamate (d) molybdenum dithiophosphate (e) Overbased calcium sulfonate (f) Neutral zinc sulfonate (g) antioxidant consists only of A grease composition for a constant velocity joint, wherein the content of component (b) is 6 to 7 mass%, the content of component (c) is 1 to 3 mass%, the content of component (d) is 0.2 to 2 mass%, the content of component (e) is 0.5 to 3 mass%, the content of component (f) is 0.8 to 3 mass%, and the content of component (g) is 0.2 to 1 mass%, based on the total mass of the composition.

9. (a) Base oil (b) Aliphatic diurea thickener (c) Molybdenum dithiocarbamate (d) molybdenum dithiophosphate (e) Overbased calcium sulfonate containing calcium carbonate and having a base number of 300 mg KOH / g or more (f) Neutral zinc sulfonate (g) Amine-based antioxidant Including, A grease composition for a constant velocity joint, wherein, based on the total mass of the composition, the content of component (b) is 6 to 7 mass%, the content of component (c) is 1 to 3 mass%, the content of component (d) is 0.2 to 2 mass%, the content of component (e) is 1.2 to 3 mass%, the content of component (f) is 0.8 to 3 mass%, and the content of component (g) is 0.2 to 1 mass%, and the mass ratio of components (e):(f) is 7:3 to 1.1:1.

0.

10. (a) Base oil (b) Aliphatic diurea compounds represented by formula (1) R 1 -NHGNH-R 2 -NHGNH-R 3 (1) (In the formula, R 1 and R 3 is a linear alkyl group having 8 carbon atoms, and R 2 is a group derived from diphenylmethane diisocyanate. (c) A mixture of an oil-soluble molybdenum dithiocarbamate and an oil-insoluble molybdenum dithiocarbamate. (d) molybdenum dithiophosphate (e) Calcium alkyl aromatic sulfonate containing calcium carbonate and having a base number of 300 to 500 mg KOH / g (f) zinc dinonylnaphthalenesulfonate having a base number of 10 mgKOH / g or less (g) alkyldiphenylamine Including, A grease composition for a constant velocity joint, wherein, based on the total mass of the composition, the content of component (b) is 6 to 7 mass%, the content of component (c) is 1 to 3 mass%, the content of component (d) is 0.2 to 2 mass%, the content of component (e) is 1.2 to 3 mass%, the content of component (f) is 0.8 to 3 mass%, and the content of component (g) is 0.2 to 1 mass%, and the mass ratio of components (e):(f) is 7:3 to 1.1:1.

0.

11. A constant velocity joint packed with the grease composition according to any one of claims 1 to 10.

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