JP2002020776A - Grease composition for constant velocity joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a grease composition for a constant velocity joint, capable of preventing the ball-type constant velocity joint driven at a more high-speed condition from flaking. SOLUTION: This grease composition for the constant velocity joint contains (a) a base oil, (b) a urea-based thickening agent, (c) over based sodium sulfonate, (d) a sulfur-based extreme pressure agent and (e) a phosphorus-based abrasion- resistant material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a grease composition for a constant velocity joint, and more particularly to a grease composition for a constant velocity joint having excellent durability. The grease composition for a constant velocity joint of the present invention is particularly suitable for use in a ball type constant velocity joint of an automobile.

[0002]

2. Description of the Related Art In the recent automobile industry, FF vehicles are rapidly increasing in terms of weight reduction and securing a living space. A constant velocity joint (CVJ) is widely used as an indispensable component for a front-wheel drive vehicle. Among these CVJs, ball type constant velocity joints usually have a structure in which torque is transmitted by six balls, and these constant velocity joints are subjected to complicated rolling and sliding reciprocation under high surface pressure during rotation. In addition, stress is repeatedly applied to the ball and the metal surface in contact with the ball, and the flaking phenomenon due to metal fatigue is apt to occur. 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, and the use conditions of constant velocity joints have been further increased. Flaking is more likely to occur, and countermeasures are needed. As a grease composition for a constant velocity joint for solving the above problems, for example, there is a grease composition disclosed in JP-A-6-57283. According to the grease composition for a constant velocity joint, flaking can be prevented to some extent. However, the use conditions of the constant velocity joint have been further increased, and the constant velocity joint having more excellent durability has been provided. Grease compositions are required.

[0003] Accordingly, an object of the present invention is to provide a grease composition for a constant velocity joint which can prevent flaking of a ball type constant velocity joint operated at higher speed conditions.

[0004]

Means for Solving the Problems Flaking is a damage that is originally treated by increasing the thickness of an oil film and reducing stress. Generally, an additive such as an extreme pressure agent or an antiwear agent is effective. Is not allowed to play. It is known that the combination of a basic sodium sulfonate and a sulfur-based extreme pressure agent improves the extreme pressure performance, and is a measure for preventing seizure, but is not a measure for preventing flaking.
This is because the wear applied to the lubricated surface is too large to prevent the flaking from being prevented. Therefore, wear can be suppressed by further using a phosphorus-based antiwear agent, that is, stress can be reduced and flaking can be effectively prevented. 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) base oil, (b) urea-based thickener, (c) overbased sodium sulfonate, (d) sulfur-based extreme pressure agent, and (e) phosphorus-based antiwear agent.

[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 contains the following components (a), (b), (c), (d) and (e). (A) base oil, (b) urea-based thickener, (c) overbased sodium sulfonate, (d) sulfur-based extreme pressure agent, and (e) phosphorus-based antiwear agent. 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.
In terms of cost, it is preferable to use mineral oil,
It is preferable to use a base oil containing a mineral oil as a main component and a synthetic oil mixed therewith.

As the thickener of component (b), urea compounds currently used as thickeners can be used. Examples of the urea compound include diurea and triurea depending on the number of urea groups, and polyureas such as tetraurea are known as those having four or more urea groups, and these urea compounds can be used without limitation. . The diurea compound is obtained, for example, by reacting a diisocyanate with a monoamine. Examples of the isocyanate include phenylene diisocyanate (TDI), diphenyl isocyanate, phenyl diisocyanate, and diphenylmethane diisocyanate (MDI). Examples of the monoamine include octylamine, dodecylamine, hexadecylamine, octadecylamine, and oleylamine. , 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.

The above polyurea compound is obtained, for example, by reacting a diisocyanate with a diamine. Examples of the diisocyanate include those similar to those used for producing the diurea compound. Examples of the diamine include ethylenediamine, propanediamine, hexanediamine, octanediamine, phenylenediamine,
And tolylenediamine and xylenediamine. The method of reacting the diisocyanate with the diamine is not particularly limited, and can be carried out by a conventionally known method. Particularly preferred urea thickeners include diurea compounds obtained by reacting octylamine, stearylamine, cyclohexylamine, aniline or a mixture thereof with a diisocyanate compound.

The overbased sodium sulfonate as the component (c) is known as a rust preventive for metalworking oils, a cleaning dispersant for automobile engine oils or an extreme pressure agent.
Overbasicity of synthetic sulfonic acids such as petroleum sulfonic acid overbased sodium salt, dinonylnaphthalene sulfonic acid, alkylbenzene sulfonic acid and alkyl aromatic sulfonic acid obtained by sulfonation of aromatic hydrocarbon in lubricating oil fraction Compounds selected from the group consisting of sodium salts and overbased sodium salts of oxidized waxes may be mentioned. Of these, particularly preferred are overbased sodium salts of dinonylnaphthalenesulfonic acid and alkyl aromatic sulfonic acids.

The sulfur-based extreme pressure agent of the component (d) includes various lubricating oils and greases such as industrial gear oils, metal high-speed gear oils for automobiles, metal working oils such as cutting oils and drawing oils, hydraulic oils, and automatic transmission oils. It is a weight-resistant additive containing sulfur in its molecular structure, which is known to be used in (1), and does not contain the overbased sodium sulfonate of the component (c). 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; zinc salts and molybdenum salts of dialkyldithiophosphoric acids. Organic metal compounds; organic compounds such as dithiocarbamic acid, thiocarbonate, and xanthate that do not contain metals; sulfurized oils and fats and sulfurized esters obtained by sulfurizing animal and vegetable oils such as castor oil, rapeseed oil, tallow and lard, and olefins; Sulfurized olefins and polysulfides. Further, solid lubricants such as molybdenum salts of dialkyldithiocarbamic acids, molybdenum salts of dialkyldithiophosphoric acids, molybdenum disulfide, and ammonium sulfide 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. Among the sulfur extreme pressure agents of the component (d), preferred are sulfurized olefins and / or sulfurized fats and oils. Also,
It is more preferred to use a mixture of a sulfurized olefin or a sulfurized oil with a molybdenum salt of a dialkyldithiocarbamic acid and / or a molybdenum salt of a dialkyldithiophosphoric acid. In the present invention, a commercially available sulfur-based extreme pressure agent of the component (d) may be used. Examples of such sulfur-based extreme pressure agents include, for example, Anglamol 33 manufactured by Lubrizol Japan, and Mobil Chemical Co., Ltd.
Mobilad C-100 and DILUBE G-290 manufactured by Dainippon Ink and the like.

The phosphorus-based antiwear agent (e) is used in various lubricating oils such as gear oils, metal working oils, hydraulic oils, and automatic transmission oils, similarly to the sulfur-based extreme pressure agent (d). Is a load-bearing additive containing phosphorus in its molecular structure. Specific examples of the phosphorus antiwear agent include zinc salts of dialkyldithiophosphoric acids; organometallic compounds such as molybdenum salts; phosphites such as tributyl phosphite and trioleyl phosphite; tricresidyl; Phosphates such as phosphate and dilauryl acid phosphate; amine phosphates such as dibutyl octylamine phosphate and dilauryl octylamine phosphate; triphenyl phosphorothionate and alkanol Phosphorothionates represented by chelated phosphorothionate; solid lubricants represented by calcium phosphate; and diphenyl hydrogen phosphite. In the present invention, as the phosphorus-based antiwear agent of the component (e), a commercially available one can be used. Examples of such phosphorus-based antiwear agents include JP-260 and JP-2 manufactured by Johoku Chemical Co., Ltd.
12. TPP and TCP manufactured by Daihachi Chemical Co., Ltd. Commercial products containing the sulfur extreme pressure agent (d) and the phosphorus antiwear agent (e) are also commercially available, and such products can be used in the present invention.
Such commercially available products include, for example, Anglamol 99 and Angramol 98A manufactured by Lubrizol Japan Ltd.
Mobilad G-305, Mobilad G-210 manufactured by Mobil Chemical
And the like.

In the grease composition for a constant velocity joint of the present invention, the base oil of the component (a) is preferably 45.0 to 98.7 based on the total weight of the grease composition for a constant velocity joint.
% By mass, urea thickener of component (b): 1 to 25% by mass, overbased sodium sulfonate of component (c):
It contains 0.1 to 10% by mass. The content of the sulfur-based extreme pressure agent of the component (d) and the content of the phosphorus-based antiwear agent of the component (e) are as follows: the content of sulfur is 0.1 to 5% by mass in the total composition; It is preferable that the amount is 0.001 to 0.3% by mass in the composition. The grease composition for a constant velocity joint of the present invention is more preferably 75.0 to 94.5% by mass of the base oil of the component (a), based on the total weight of the grease composition for a constant velocity joint, (b) The urea thickener of the component: 4 to 20% by mass, and the overbased sodium sulfonate of the component (c): 0.5 to 5% by mass.
The sulfur extreme pressure agent of the component (d) and the phosphorus antiwear agent of the component (e) each have a sulfur content of 0.1 to 0.1% in the total composition.
3.0 mass%, phosphorus content is 0.005 to 0.005 in the total composition.
More preferably, the amount is 0.15% by mass.

When the content of the urea thickener of the component (b) is less than 1% by mass, the thickening effect is reduced and the grease is hardly formed.
Since the obtained composition may be too hard and the initial effect may not be obtained, it is preferable to be within the above range. When the content of the overbased sodium sulfonate of the component (c) is less than 0.1% by mass, it is difficult to obtain an initial effect, and even if the content exceeds 10% by mass, the effect is increased. Since there may be no case, it is preferable to be within the above range.

The grease composition for a constant velocity joint of the present invention is characterized in that the sulfur content of the sulfur extreme pressure agent is
It is preferably 0.1 to 5% by mass, and 0.1 to 3% by mass.
More preferably, it is 0% by mass. If the sulfur content of the sulfur extreme pressure agent is less than 0.1% by mass of the total composition, it is difficult to obtain the initial effect, and even if it exceeds 5% by mass, the effect does not increase. Therefore, it is preferable to be within the above range. In the grease composition for a constant velocity joint according to the present invention, the phosphorus content of the phosphorus-based antiwear agent is preferably 0.001 to 0.3% by mass of the whole composition, and is preferably 0.005 to 0.3% by mass. More preferably, it is 0.15% by mass. The phosphorus content of the phosphorus-based antiwear agent is,
If the amount is less than 0.001% by mass of the total composition, it is difficult to obtain the initial effect, and if the amount exceeds 0.3% by mass, the effect may not be increased. preferable.

The grease composition for a constant velocity joint of the present invention includes the above (a), (b), (c), (d) and (e).
In addition to the components, antioxidants, rust inhibitors, and polymer additives generally used for various lubricating oils and greases can be added. Further, additives other than the above-mentioned components (c), (d) and (e), such as extreme pressure agents, friction modifiers, anti-wear agents and solid lubricants, 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.

[0015]

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. Examples 1 to 5 and Comparative Examples 1 to 4 To the base grease containing the thickener and the base oil, the respective components were added so that the ratios shown in Table 1 or Table 2 were obtained, and three stages were added while appropriately adding the base oil. The consistency was adjusted to No. 1 grade with a roll mill to obtain a grease composition for a constant velocity joint.
The thickeners shown in the table are as follows. Urea A: diphenylmethane diisocyanate (MD
I) Diurea compound obtained by reaction of octylamine with urea B: Diurea compound obtained by reaction of diphenylmethane diisocyanate with cyclohexylamine and aniline Li soap: lithium salt of 12-hydroxystearic acid

Comparative Example 5 95.0 parts of alicyclic urea grease, molybdenum disulfide 1.0
Parts, 2.0 parts of molybdenum sulfide dialkyldithiocarbamate (trade name: Sakura Roof 600, manufactured by Asahi Denka Kogyo KK) and lead diamyl dithiocarbamate (trade name: Vanlube 71)
A grease composition for constant velocity joints containing 2.0 parts of a base oil (manufactured by RT Vanderbilt) was prepared. The base oils used in the above Examples and Comparative Examples are as follows.

[0017]

[Table 1]

[0018]

[Table 2]

In Tables 1 and 2, 1) to 5) show the following. 1) Sulfur-based extreme pressure agent (trade name: Anglamol 33 manufactured by Lubrizol Japan) 2) MoDTC (molybdenum dialkyl dithiocarbamate,
Product name Molyvan A R. TVanderbilt) 3) Phosphorus anti-wear agent (diphenyl hydrogen phosphite, trade name JP-260 Johoku Chemical Co., Ltd.) 4) SP type extreme pressure agent A (trade name Anglamol 99 Japan) 5) SP-based extreme pressure agent B (trade name: Anglamol 98A, manufactured by Nippon Lubrizol Co.) The following were used as the overbased sodium sulfonate, the overbased calcium sulfonate, and the neutral sodium sulfonate. Overbased sodium sulfonate (brand name Lubrizol 5
318A: Base number 450, manufactured by Lubrizol Japan Ltd. Overbased calcium sulfonate (trade name: Bryton C-40)
0c Witco Corporation) Neutral sodium sulfonate (Product name NA-SUL SS King
The numbers in Tables 1 and 2 represent% by mass. Also,
Tables 1 and 2 also show the sulfur content of the sulfur-based extreme pressure agent and the phosphorus content of the phosphorus-based antiwear agent in the grease compositions for constant velocity joints. The unit is mass% of the total composition.
It is.

The grease composition for a constant velocity joint was evaluated for physical properties by the following test methods. Table 2 shows the results obtained for the consistency. The consistency of the grease composition for a constant velocity joint of Comparative Example 5 was 300. <Consistency> According to JIS K 2220 5.3. <Durability Test> Using a commercially available # 100 size bar field type joint under the following conditions, a durability test was performed under a high-speed rotation condition under which the movement of the ball in the joint was higher. Test conditions Rotation speed: 2000 rpm Torque: 30 kg · f Angle: 7 ° Evaluation was performed according to the following evaluation criteria. The test was performed for up to 500 hours. Table 3 shows the results. Evaluation criteria ○: No peeling occurred. ×: Peeling occurred.

[0021]

[Table 3]

As is clear from Table 3, the grease composition for a constant velocity joint of the present invention did not peel off for up to 300 hours, indicating that the durability was excellent. In addition, the mixture containing molybdenum dialkyldithiocarbamate showed no peeling up to 500 hours, indicating that the durability was further excellent. All the grease compositions for constant velocity joints of Comparative Examples were peeled by 100 hours.

As described in detail above, the grease composition for a constant velocity joint of the present invention comprises (a) a base oil, (b) a urea thickener, (c) an overbased sodium sulfonate,
By containing (d) sulfur-based extreme pressure agent and (e) phosphorus-based antiwear agent, it has excellent durability and prevents flaking of ball-type constant velocity joints operated under higher speed conditions. Grease composition for a constant velocity joint.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) C10M 135/18 C10M 135/18 137/02 137/02 137/04 137/04 137/08 137/08 137/10 137 / 10 A Z 159/24 159/24 // C10N 10:02 C10N 10:02 10:12 10:12 30:00 30:00 Z 40:04 40:04 50:10 50:10 (72) Inventor Tomei Daimei 1-4-1 Tsujido Shindai, Fujisawa-shi, Kanagawa Prefecture Kyodo Yushi Co., Ltd. (72) Inventor Hisayuki Osawa 1-4-1 Tsujido Shindai, Fujisawa-shi, Kanagawa Kyodo Yushi Co., Ltd. 1-4-1 Tsujido Shindai Kyodo Yushi Co., Ltd. (72) Inventor Atsushi Suzuki 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Co., Ltd. (72) Koji Saito 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation F term (for reference) 4H104 BE13B BG02C BG04C BG10C BH02C BH03C BH05C BH06C BH07C CE14B DA02A DB07C EB02 FA01 FA06 LA20 PA02 QA18

Claims (5)

[Claims] 1. A grease composition for constant velocity joints comprising the following components: (A) base oil, (b) urea-based thickener, (c) overbased sodium sulfonate, (d) sulfur-based extreme pressure agent, and (e) phosphorus-based antiwear agent. 2. The grease composition for a constant velocity joint according to claim 1, wherein the sulfur-based extreme pressure agent is a sulfurized olefin and / or a sulfurized fat or oil. 3. The grease composition for a constant velocity joint according to claim 2, wherein the sulfur content of the sulfur-based extreme pressure agent is 0.1 to 5% by mass in the whole composition. 4. The phosphorus-containing antiwear agent according to claim 3, wherein the phosphorus content of the total composition is 0.001 to 0.3% by mass.
The grease composition for a constant velocity joint according to the above. 5. The uniform velocity according to claim 4, wherein the sulfur-based extreme pressure agent is a mixture of a sulfurized olefin and / or a sulfurized oil and fat, a molybdenum salt of a dialkyldithiocarbamic acid and / or a molybdenum salt of a dialkyldithiophosphoric acid. Grease composition for joints.