JP2002038177A - Grease composition for constant velocity joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a grease composition to be used in stationary-type constant velocity joints, excellent in antiflaking performance and durability as well. SOLUTION: This grease composition for constant velocity joints comprises (a) a base oil, (b) a diurea-based thickening agent of general formula (I): R1-NH- CO-NH-C6H4-p-CH2-C6H4-p-NH-CO-NHR2 (wherein, R1 and R2 are each a 6C or 7C aryl or cyclohexyl), (c) molybdenum dithiocarbamate, (d) molybdenum disulfide, (e) a phosphorus-free sulfur-based extreme-pressure agent, and (f) sodium sulfonate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grease composition for a constant velocity joint, and more particularly, to a durable constant velocity joint capable of lubricating a constant velocity joint and preventing flaking of a lubricated portion. The present invention relates to a grease composition for use. The grease composition for a constant velocity joint of the present invention can prevent the occurrence of flaking and has excellent durability, and thus is particularly suitable as a grease composition for a fixed type constant velocity joint.

[0002]

2. Description of the Related Art In a constant velocity joint, an extremely high surface pressure is applied to the constant velocity joint to be lubricated, and the joint performs a complicated rolling motion. The phenomenon, namely flaking of the joint, is likely to occur. Conventionally, lubricating greases used in such constant velocity joints include, for example, lithium-based extreme pressure grease containing molybdenum disulfide-containing and sulfur-phosphorus-based extreme pressure agent or lead salt of naphthenic acid. And the like. In the recent automobile industry, FF vehicles are rapidly increasing in terms of weight reduction and securing living space. A constant velocity joint (CVJ) is widely used as an indispensable component for a front-wheel drive vehicle. Among these CVJs, fixed type constant velocity joints, especially Barfield type constant velocity joints (BJ)
Has a structure in which torque is transmitted by six balls. In these constant velocity joints, there is a problem that the flaking phenomenon due to metal fatigue is likely to occur due to repeated stress applied to the ball and the metal surface in contact with the ball due to complicated reciprocating motion of rolling and sliding under high surface pressure during rotation. is there. In addition, the size of constant velocity joints has been reduced due to the recent increase in engine output and the weight reduction of automobiles for improved fuel efficiency, and the surface pressure has become relatively high. The grease composition cannot sufficiently prevent the flaking phenomenon.

Accordingly, an object of the present invention is to provide a grease composition for a constant velocity joint which is used in a fixed type constant velocity joint and has excellent anti-flaking performance and excellent durability.

[0004]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that a grease composition for a constant velocity joint containing a specific component can achieve the above object. The present invention has been made based on the above findings, and provides a grease composition for a constant velocity joint containing the following components. (A) a base oil, (b) a diurea-based thickener represented by the following general formula (I), R ¹ -NH-CO-NH-C ₆ H ₄ -p-CH ₂ -C ₆ H ₄ -p -NH-CO-NHR ² (I) (wherein, R ¹ and R ² may be the same or different and are an aryl group having 6 or 7 carbon atoms or a cyclohexyl group) (c) Molybdenum dithiocarbamate,
(D) molybdenum disulfide, (e) a sulfur-based extreme pressure agent containing no phosphorus, and (f) sodium sulfonate.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the grease composition for a constant velocity joint according to the present invention will be described in detail. The grease composition of the present invention comprises the following components (a), (b), (c), (d),
(E) and (f). (A) a base oil, (b) a diurea-based thickener represented by the following general formula (I), R ¹ -NH-CO-NH-C ₆ H ₄ -p-CH ₂ -C ₆ H ₄ -p -NH-CO-NHR ² (I) (wherein, R ¹ and R ² may be the same or different and are an aryl group having 6 or 7 carbon atoms or a cyclohexyl group) (c) Molybdenum dithiocarbamate,
(D) molybdenum disulfide, (e) a sulfur-based extreme pressure agent containing no phosphorus, and (f) sodium sulfonate. First,
The component (a) will be described. Examples of the base oil of the component (a) include commonly used lubricating oils such as mineral oils, ether-based synthetic oils, ester-based synthetic oils, and hydrocarbon-based synthetic oils, or mixed oils thereof. It is not limited to. From the viewpoint of cost, it is preferable to use mineral oil, and it is also preferable to use a base oil containing a mineral oil as a main component and a synthetic oil mixed therewith.

The diurea thickener of the above-mentioned component (b) is represented by the following general formula (I). R ¹ -NH-CO-NH-C ₆ H ₄ -p-CH ₂ -C ₆ H ₄ -p-NH-CO-NHR ² (I) In the general formula (I), R ¹ and R ² are They may be the same or different and are an aryl group having 6 or 7 carbon atoms or a cyclohexyl group. The diurea thickener represented by the general formula (I) is obtained, for example, by reacting a diisocyanate with a monoamine. Examples of the isocyanate include diphenylmethane-4,4'-
Examples include diisocyanate, phenylene diisocyanate, diphenyl isocyanate, and phenyl diisocyanate. Examples of the monoamine include aniline, p-toluidine, and cyclohexylamine. The method of reacting the diisocyanate with the monoamine is not particularly limited, and can be carried out by a conventionally known method.

As the molybdenum dithiocarbamate of the component (c), a compound represented by the following general formula (II) is used. (R ³ R ⁴ N-CS-S) ₂ -Mo ₂ OmSn (II) In the general formula (II), R ³ and R ⁴ may be the same or different and have 1 to 1 carbon atoms. 24, preferably an alkyl group having 3 to 18 carbon atoms, m is 0 to 3, and m + n = 4.

[0008] Molybdenum disulfide as the component (d) is generally widely used as a solid lubricant.
This compound has a layered lattice structure, is easily sheared into a thin layer by sliding motion, prevents metal contact, and has an anti-seizure effect. The sulfur-based extreme pressure agent containing no phosphorus component (e) is an industrial gear oil,
It is known to be used in various lubricating oils and greases, such as metal working oils such as hypoid gear oils, cutting oils, and drawing oils for automobiles, hydraulic oils, and automatic transmission oils.It contains sulfur in its molecular structure and contains phosphorus. Is a non-weighted additive. Specific examples of the sulfur-based extreme pressure agent include, for example, zinc salts, molybdenum salts, copper salts, bismuth salts, nickel salts, and iron salts of dialkyldithiocarbamic acids; organometallic compounds represented by molybdenum salts; Organic compounds such as dithiocarbamic acid, thiocarbonate, and xanthate; sulfurized oils and fats obtained by sulfurizing animal and vegetable oils such as castor oil, rapeseed oil, beef tallow, and lard; and sulfurized olefins and polysulfides obtained by sulfurizing olefins. No. Further, solid lubricants represented by molybdenum salts of dialkyldithiocarbamic acids, ammonium sulfide and the like can also be used. In the present invention, the sulfur-based extreme pressure agent may be used alone, or two or more kinds thereof may be used in combination. In addition, the sulfur-based extreme pressure agent containing no phosphorus component (e) has a sulfur content of 35 to 50.
% By mass is preferred. Commercially available sulfur-based extreme pressure agents can also be used. Examples of such sulfur-based extreme pressure agents include, for example, Anglamol 33 manufactured by Lubrizol Japan, and DAILUB manufactured by Dainippon Ink.
E G-290, MobiladC-100, Mobil manufactured by Mobile Chemical
ad C-170, Elco Elco 217, and Aquitaine
TPS32 and the like. The sodium sulfonate of the component (f) is generally used as a rust inhibitor and a cleaning dispersant.

The grease composition for a constant velocity joint of the present invention preferably comprises (b) a diurea-based thickener: 1 to 25 with respect to the total weight of the grease composition for a constant velocity joint.
Mass%, (c) molybdenum dithiocarbamate: 0.1
To 10% by mass, (d) molybdenum disulfide: 0.1 to 10
% By mass, (e) sulfur-based extreme pressure agent not containing phosphorus: 0.1
-10% by mass, and (f) sodium sulfonate:
It contains 0.1 to 10% by mass. The grease composition for a constant velocity joint of the present invention is more preferably (b) a diurea-based thickener: 4 to 20% by mass, and (c) molybdenum dithiocarbamate, based on the total weight of the grease composition for a constant velocity joint. : 0.5 to 8% by mass, (d) molybdenum disulfide: 0.5 to 5% by mass, (e) a sulfur-based extreme pressure agent containing no phosphorus: 0.5 to 5% by mass, and (f) Sodium sulfonate: contains 0.5 to 5% by mass.

When the content of the diurea-based thickener of the component (b) is less than 1% by mass, the thickening effect is reduced and the grease is hardly formed. When the content exceeds 25% by mass, the obtained composition is obtained. Is so hard that the initial effect may not be obtained. When the content of the molybdenum dithiocarbamate of the component (c) is less than 0.1% by mass, it is difficult to obtain the initial effect, and even when the content exceeds 10% by mass, the initial effect does not increase. In some cases, it is preferable to be within the above range. If the content of the molybdenum disulfide of the component (d) is less than 0.1% by mass, it is difficult to obtain the initial effect, and even if the content exceeds 10% by mass, the initial effect does not increase. In some cases, it is preferable to be within the above range. When the content of the sulfur-based extreme pressure agent containing no phosphorus component of the component (e) is less than 0.1% by mass, it is difficult to obtain an initial effect, and even if the content exceeds 10% by mass, Since there is a case where the initial effect does not increase, it is preferable to be within the above range. When the content of the sodium sulfonate of the component (f) is less than 0.1% by mass, it is difficult to obtain an initial effect, and even when the content exceeds 10% by mass, the effect does not increase. Because there is
It is preferable to be within the above range.

The grease composition for a constant velocity joint of the present invention may contain (g) calcium sulfonate in addition to the above components (a) to (f). (G) is generally
It is used as a rust inhibitor and a cleaning dispersant. When the above-mentioned (g) calcium sulfonate is contained in the grease composition for a constant velocity joint of the present invention, the content is preferably 0.1 to 10% by mass relative to the total weight of the grease composition for a constant velocity joint. %, More preferably 0.5 to 5% by mass. When the content of the calcium sulfonate of the component (g) is less than 0.1% by mass, it is difficult to obtain an initial effect, and the content is 10% by mass.
In some cases, the effect is not increased even if the content exceeds the above range, so that the content is preferably within the above range.

The grease composition for a constant velocity joint of the present invention is generally used in various lubricating oils and greases in addition to the above components (a) to (f) or (a) to (g). Antioxidants, rust inhibitors, polymer additives can be added. When the above additive is contained, its content is preferably 0.1 to 10% by mass based on the whole amount of the grease composition for a constant velocity joint.

[0013]

The present invention will be described in more detail with reference to the following examples. It goes without saying that the scope of the present invention is not limited to the examples. In Examples 1-4 and Comparative Examples 1-3 , 410.0 g of base oil and diphenylmethane-4,
Take 101.2 g of 4'-diisocyanate and stir to obtain a mixture, which is heated to a temperature of 70-80C. In a separate container, take 410.0 g of base oil, 56.3 g of cyclohexylamine and 22.5 g of aniline, stir to obtain a mixture, heat to a temperature of 70-80 ° C., and mix the mixture with 410.0 g of base oil and Diphenylmethane-4,4 '
-Into a mixture of 101.2 g of diisocyanate.
Then, the mixture is reacted for 30 minutes while stirring, then the temperature is increased to 160 ° C. while stirring, and then left to cool, and the (a) base oil (hereinafter, referred to as “a”) containing the diurea-based thickener of the component (b) Base grease).
Next, the components (c) to (f) or (g) were added to the obtained base grease so that the proportions shown in Tables 1 and 2 were obtained (the numbers shown in Tables 1 and 2 are% by mass). In addition, a three-stage roll mill was used to adjust the consistency to the No. 1 grade while appropriately adding a base oil to obtain a grease composition for a constant velocity joint. The base oils used in the above Examples and Comparative Examples are as follows.

The physical properties of the grease compositions for constant velocity joints of the above Examples and Comparative Examples and a commercially available grease composition (Comparative Example 4) were evaluated by the following methods. The obtained results are also shown in Tables 1 and 2. <Consistency> According to JIS K2220 5.3. <Drip point> According to JIS K 2220 5.4. Further, a durability test was performed by the following method. The test results are shown in FIG. The results were relatively evaluated with the example 1 being 100, and the relative life ratio was shown in FIG. <Durability test> Using a commercially available # 87 size Barfield type joint, the time required for the joint to reach its life under a predetermined high-speed rotation and high torque condition was measured.

[0015]

[Table 1]

[0016]

[Table 2]

In Tables 1 and 2, 1) to 7) show the following. 1) A diurea compound produced by using a mixture of cyclohexylamine and aniline as a monoamine and using diphenylmethane-4,4'-diisocyanate as an isocyanate. 2) Trade name: Molyvan A RTVanderbilt 3) Trade name: Molyvan 822 RTVanderbilt 4) Trade name: Molysulfide, CLIMAX MOLYBDENUM (average particle size 0.45μm) 5) Trade name: Anglamol 33 Japan Lubrizol ( Lubrizol)
6) Product name: LUBRIZOL 5318A Japan Lubrizol
ol) 7) Product name: LUBRIZOL 5283 Lubrizol Japan
l) * Lithium extreme pressure grease containing molybdenum disulfide on the market

FIG. 1 shows the results of the durability test. As is clear from FIG. 1, the grease compositions for constant velocity joints of Examples 1 to 4 exhibited excellent durability as compared with the grease compositions for constant velocity joints of Comparative Examples 1 to 4.

As described in detail above, the grease composition for a constant velocity joint of the present invention comprises (a) a base oil, (b) a diurea-based thickener represented by the following general formula (I), R ^1- NH-CO-NH-C ₆ H ₄ -p-CH ₂ -C ₆ H ₄ -p-NH-CO-NHR ² (I) (wherein R ¹ and R ² are the same or different (C) molybdenum dithiocarbamate, which is an aryl group or a cyclohexyl group having 6 or 7 carbon atoms.
By containing (d) molybdenum disulfide, (e) a sulfur-based extreme pressure agent containing no phosphorus, and (f) sodium sulfonate, it is possible to prevent the occurrence of flaking in the lubricated portion and to have excellent durability. It becomes a grease composition for speed joints.

[Brief description of the drawings]

FIG. 1 is a graph showing the results of a durability test of a grease composition for a constant velocity joint.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C10M 135/10 C10M 135/10 135/14 135/14 135/18 135/18 // C10N 10:02 C10N 10:02 10:04 10:04 10:10 10:10 10:12 10:12 10:16 10:16 30:00 30:00 Z 30:06 30:06 40:04 40:04 50:10 50 : 10 (72) Inventor Takashi Okaba 1-4-1 Tsujido Jindai, Fujisawa-shi, Kanagawa Kyodo Yushi Co., Ltd. (72) Minoru Ishijima 27-3-306, Chuo-cho, Isesaki-shi, Gunma F-term (reference) 4H104 AA18C AA19C BE13B BG02C BG04C BG06C BG08C BG10C DA02A EB02 FA01 FA02 FA05 FA06 FA08 LA03 LA20 PA03 QA18

Claims (5)

[Claims] 1. A grease composition for constant velocity joints comprising the following components: (A) a base oil, (b) a diurea-based thickener represented by the following general formula (I), R ¹ -NH-CO-NH-C ₆ H ₄ -p-CH ₂ -C ₆ H ₄ -p -NH-CO-NHR ² (I) (wherein, R ¹ and R ² may be the same or different and are an aryl group having 6 or 7 carbon atoms or a cyclohexyl group) (c) Molybdenum dithiocarbamate,
(D) molybdenum disulfide, (e) a sulfur-based extreme pressure agent containing no phosphorus, and (f) sodium sulfonate. 2. The grease composition for a constant velocity joint according to claim 1, further comprising (g) calcium sulfonate. 3. The composition of claim 1, wherein (b) the content of the diurea thickener is 1 to 25% by mass, (c) the content of molybdenum dithiocarbamate is 0.1 to 10% by mass, and (d) Molybdenum sulfide content of 0.1 to 10% by mass, (e)
When the content of the sulfur-based extreme pressure agent containing no phosphorus component is 0.1 to 10
Mass%, the content of (f) sodium sulfonate is 0.1%
The grease composition for a constant velocity joint according to claim 1, which is 1 to 10% by mass. 4. The composition according to claim 1, wherein the content of the diurea thickener is 1 to 25% by mass, the content of the molybdenum dithiocarbamate is 0.1 to 10% by mass, based on the total weight of the composition. (D) the content of molybdenum disulfide is 0.1 to 10% by mass, (e) the content of sulfur-based extreme pressure agent not containing phosphorus is 0.1 to 10% by mass, and (f) the content of sodium sulfonate The amount is 0.1 to 10% by mass, and the content of (g) calcium sulfonate is 0.1 to 10% by mass.
The grease composition for a constant velocity joint according to the above. 5. The grease composition for a constant velocity joint according to claim 1, which is used for a fixed type constant velocity joint.