JP2003041280A - Grease for constant velocity joint and constant velocity joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a grease for a constant velocity joint which efficiently lubricates a constant velocity joint and can effectively reduces friction to prevent the generation of vibration, and a plunging type constant velocity joint into which this grease has been sealed. SOLUTION: The grease for a constant velocity joint is obtained by incorporating an organomolybdenum compound, a sulfur-containing organotin compound, and an organozinc compound to a base grease comprising a base oil and a thickening agent and further incorporating a sulfur-based extreme-pressure additive or a sulfur-phosphorus-based extreme-pressure additive thereinto.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a constant velocity joint grease used in automobiles and a constant velocity joint filled with the grease, and more particularly to a plunging type constant velocity joint.

[0002]

2. Description of the Related Art A plunging type constant velocity joint is typified by a double offset type constant velocity joint and a tripod type constant velocity joint. As shown in FIG. 1, the double offset type constant velocity joint has six axial track grooves 3 and 4 formed on the inner surface of the outer ring 1 and the outer surface of the spherical inner ring 2 at equal angles. The ball 5 installed in between is supported by a cage 6, the outer circumference of the cage 6 is a spherical surface 7, and the inner circumference is a spherical surface 8 adapted to the outer circumference of the infusion 2, and the centers of the respective spherical surfaces 7, 8 (a), Outer ring 1
The position is displaced in the axial direction on the axis center of. Also,
The outer circumference of the outer ring 1 and the outer circumference of the shaft 9 are covered with a boot 10, and a constant velocity joint grease 11 is hermetically filled therein.

On the other hand, in the triport type constant velocity joint, as shown in FIG. 2, three cylindrical track grooves 13 in the axial direction are formed at an equal angle on the inner surface of the outer ring 12, and the triport is incorporated inside the outer ring 12. The member 14 is provided with three leg shafts 15, a spherical roller 16 is fitted to the outside of each leg shaft 15, and a nidle 17 is incorporated between the spherical roller 16 and the leg shaft 15 to form the spherical roller 16 Is supported rotatably and slidably in the axial direction, and its spherical roller 16 is fitted in the track groove 13. Further, the outer circumference of the outer ring 12 and the outer circumference of the shaft 9 are covered with a boot 10, and the grease for a constant velocity joint 11 is hermetically filled therein.

In the plunging type constant velocity joint having the above structure, the rotational torque is transmitted by the engagement between the track grooves 3 and 4 and the ball 5 and the engagement between the track groove 13 and the spherical roller 16. For plunging, the ball 5 rolls along the track groove 3 and the spherical roller 16 rolls along the track groove 13 to absorb the rolling.

By the way, when the rotary torque is transmitted in a state where the joint takes an operating angle, in the double offset type constant velocity joint, rolling and slippage occur in fitting the track grooves 3 and 4 and the ball 5, and , Cage 6
A slip occurs between the outer ring 1 and the cage 6 and the inner ring 2. On the other hand, in the tripod type constant velocity joint, rolling and sliding occur between the track groove 13 and the spherical roller 16.

As described above, the plunging type constant velocity joint has many sliding elements as compared with rolling. Therefore, when the rotational torque is transmitted with an operating angle, an axial force is generated due to the frictional resistance of the sliding portion. For example, in the double offset type constant velocity joint, since the track groove 3 is provided on the inner surface of the outer ring 1 at intervals of 60 °, as shown in FIG. 3, an axial force is generated 6 times per rotation, On the other hand, in the tri-port type constant velocity joint, since the track grooves 13 are provided at 120 ° intervals, as shown in FIG. 4, an axial force is generated three times per rotation.

When the cycle of generation of such an axial force and the natural frequency of the engine, vehicle body, suspension, etc. match, resonance is induced in the vehicle body and an occupant feels uncomfortable.
It is desirable to make the axial force as low as possible. Therefore, in the plunging type constant velocity joint, the grease for the constant velocity joint is filled inside to reduce the friction resistance and improve the slidability.

Conventionally, such a grease for constant velocity joints has a urea-based grease containing an organic molybdenum compound (Japanese Patent Laid-Open No. 63-46299), and a urea-based grease containing molybdenum disulfide, molybdenum dithiocarbamate and sulfur. A grease containing an organic tin compound (Japanese Patent Laid-Open No. 10-183161) is known.

[0009]

However, as the demand for quietness in automobiles has increased, it has become necessary to further reduce the axial force generated from constant velocity joints, which is required in conventional greases for constant velocity joints. However, there is a problem in that the axial force generated with respect to can not be sufficiently suppressed. The present invention has been made in order to address such a problem, and is a grease for a constant velocity joint that can efficiently lubricate a constant velocity joint, effectively reduce friction, and prevent the occurrence of vibration, and the grease. The purpose is to provide a plunging type constant velocity joint.

[0010]

A grease for constant velocity joints according to the present invention comprises a base grease prepared by blending a thickener with a base oil, and an organic molybdenum compound, a sulfur-containing organotin compound, and an organic zinc compound. The feature is to do. Further, it is characterized in that a sulfur-based extreme pressure agent or a sulfur-phosphorus extreme pressure agent is further added. Further, the base grease is characterized in that the base oil is blended with a urea thickener. The organic molybdenum compound is at least one organic molybdenum compound selected from molybdenum dithiocarbamate and molybdenum dithiophosphate. The organic zinc compound is zinc dithiophosphate.

The blending ratio of the above base grease is 1 to 40% by weight of the above thickener with respect to the whole base grease.
It is characterized by being mixed. The blending ratio of the grease for constant velocity joints is
0.1-10% by weight, 0.1-10 for sulfur-containing organotin compounds
%, And 0.1 to 10% by weight of an organozinc compound, respectively, based on the total grease for constant velocity joints. When a sulfur-based extreme pressure agent or a sulfur-phosphorus-based extreme pressure agent is further contained, 0.1 to 10% by weight of the organic molybdenum compound and 0.
1 to 10% by weight, 0.1 to 10% by weight of organozinc compound, 0.1 to 10% of sulfur extreme pressure agent or sulfur-phosphorus extreme pressure agent
It is characterized in that it is contained by weight% in the grease for constant velocity joints, respectively.

In the constant velocity joint of the present invention, the rotational torque is transmitted by the engagement between the track groove and the rolling element, and the rolling element rolls along the track groove, so that the axial movement is prevented. In constant velocity joints made,
The grease filled in the constant velocity joint is the above-mentioned grease for constant velocity joint.

The axial force generated from the constant velocity joint is called induced thrust, which is the main factor of the vibration generated when the constant velocity joint is rotated, and therefore it is desirable to keep it as low as possible. It is considered that grease having a lower coefficient of friction is suitable because the axial force, that is, the induced thrust, is generated by a mechanism such as that shown in FIG. Therefore, the induced thrust was measured with an actual constant velocity joint, and the friction coefficient was measured with an actual constant velocity joint member.

The grease for constant velocity joints of the present invention is obtained by repeating the above-mentioned evaluation test. It is obtained by adding an organic molybdenum compound and a sulfur-containing organic tin compound to a base grease prepared by blending a thickener with a base oil. The induced thrust could be reduced by containing the organic zinc compound and the organic zinc compound. In addition, the constant velocity joint in which the grease for the constant velocity joint is filled has a small friction coefficient and a small induced thrust, and it is possible to significantly suppress the occurrence of minute vibration.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Base oils of the base grease component usable in the present invention include naphthene-based, paraffin-based, liquid paraffin, mineral oil such as hydrodewaxed oil, polyglycol oil such as polyalkylene glycol, and alkyl diphenyl ether. , Ether synthetic oil such as polyphenyl ether, ester synthetic oil such as diester oil and polyol ester oil, silicone oil such as polydimethylsiloxane and polyphenylmethylsiloxane, poly-α-
Examples include hydrocarbon-based synthetic oils such as olefins, and mixed oils thereof. Among these, mineral oils such as naphthene-based and paraffin-based mineral oils, which are inexpensive and easy to use industrially and have excellent boot resistance that does not deteriorate boots, are preferable.

As the thickener which can be used in the present invention,
Examples thereof include soaps such as lithium soap, lithium complex soap, strength sodium soap, calcium complex soap, aluminum soap and aluminum complex soap, and urea compounds such as diurea compounds and polyurea compounds. Urea compounds are desirable in consideration of heat resistance and the like.

Examples of urea compounds include diurea compounds and polyurea compounds. The diurea compound is obtained, for example, by the reaction of diisocyanate and monoamine. Examples of the diisocyanate include phenylene diisocyanate, diphenyl diisocyanate, diphenylmethane diisocyanate, octadecane diisocyanate, decane diisocyanate, and hexane diisocyanate.The monoamines include octylamine, dodecylamine, hexadecylamine, octadecylamine, oleylamine, aniline, and the like. Examples thereof include p-toluidine and cyclohexylamine. The polyurea compound can be obtained, for example, by reacting diisocyanate with monoamine or diamine. Examples of diisocyanates and monoamines include those similar to those used for the production of diurea compounds, and as diamines, ethylenediamine, propanediamine, butanediamine, hexanediamine, octanediamine, phenylenediamine,
Examples include tolylenediamine, xylenediamine, diaminodiphenylmethane and the like.

The urea compound is obtained by reacting an isocyanate compound with an amine compound. It is preferable that the isocyanate group of the isocyanate compound and the amino group of the amine compound are mixed in approximately equivalent amounts so that no reactive free radicals remain. A base grease for blending a urea compound with a base oil and blending various compounding agents is obtained. The base grease is produced by reacting an isocyanate compound and an amine compound in base oil.

The base grease is blended in a proportion of 1 to 40% by weight, preferably 3 to 25% by weight, based on the total weight of the base grease. The content of thickener
If it is less than 1% by weight, the thickening effect is reduced and it becomes difficult to form a grease. If it exceeds 40% by weight, the obtained base grease becomes too hard and the desired effect is hardly obtained.

The organic molybdenum compound which can be used in the present invention is molybdenum dithiocarbamate or molybdenum dithiophosphate, and the former is also referred to as molybdenum dialkyldithiocarbamate sulfide.
It is represented by.

[Chemical 1] In the formula, R ₁ and R ₂ are each an alkyl group having 1 to 24 carbon atoms, preferably 3 to 18 carbon atoms, m + n = 4, and m is 0 to 3 and n is 4 to 1.

The latter molybdenum dithiophosphate is represented by the following chemical formula 2.

[Chemical 2] In the formula, R ₃ , R ₄ , R ₅ , and R ₆ are each independently a primary or secondary alkyl group having 1 to 24 carbon atoms, preferably 3 to 20 carbon atoms, or 6 to 30 carbon atoms, preferably 6 to 30 carbon atoms. 8 to 18 allyl groups are shown. As the organic molybdenum compound that can be used in the present invention, one kind or two or more kinds can be used from the organic molybdenum compounds represented by the above chemical formulas 1 and 2.

As the sulfur-containing organotin compound which can be used in the present invention, those represented by the following chemical formula 3 are preferable.

[Chemical 3] In the formula, R ₇ represents an alkyl group, and X represents —S— (CH ₂ ) _n—
CO-OR ₈ or -S- (CH ₂₎ shows the _{n -O-CO-R 8,} R 8 is an alkyl or alkenyl radical, n is
It represents an integer of 1 to 18, m represents an integer of 0 to 3, and when two or more R ₇ and X are present, they may be the same or different. Preferred as the alkyl group represented by R ₇ are those having 1 to 18 carbon atoms, for example, methyl, butyl, octyl, octadecyl and the like. Preferable examples of the alkyl group and alkenyl group represented by R ₈ are those having 1 to 18 carbon atoms such as methyl, octyl, dodecyl, octadecyl and oleyl. More specific examples include dimethyltin bis (isooctylthioglycol), monomethyltinbis (isooctylthioglycol), di (n-octyl) tinbis (isooctylmercaptoacetate), monomethyltintris (2 -Mercaptoethyl oleate), dimethyltin bis (2-mercaptoethyl oleate) and the like.

The organozinc compound that can be used in the present invention is preferably zinc dithiophosphate represented by the following chemical formula 4.

[Chemical 4] In the formula, R ₉ is an alkyl group having 1 to 24 carbon atoms or 6 carbon atoms.
~ 30 allyl groups.

As the sulfur-based extreme pressure agent or sulfur-phosphorus-based extreme pressure agent that can be used in the present invention, known extreme pressure agents can be used. For example, sulfurized fats and oils, sulfurized olefins, tricresyl phosphate, thiophosphate, thiophosphite and the like can be exemplified. These are used alone or in combination.

The grease for constant velocity joints of the present invention includes
In order to enhance the excellent performance, known additives can be added as necessary. Examples of the additives include amine-based, phenol-based, sulfur-based antioxidants, petroleum sulfonates, dinonylnaphthalene sulfonates, rust inhibitors such as sorbitan esters, benzotriazole, and metal inerts such as sodium nitrite. Agents, viscosity index improvers such as polymethacrylate and polystyrene, solid lubricants such as molybdenum disulfide and graphite, amines,
Examples thereof include oiliness agents such as amides, fatty acids, fatty acid ester oils and fats, and the like, and these can be added alone or in combination of two or more kinds.

The compounding ratio of the grease for constant velocity joints is
Organic molybdenum compounds are added to the above-mentioned base grease.
0.1-10 wt%, preferably 0.1-5 wt%, sulfur-containing organotin compound 0.1-10 wt%, preferably 0.5-5
% By weight, and 0.1 to 10% by weight, preferably 0.5 to 5% by weight, of an organozinc compound, respectively added to the entire grease for constant velocity joints, and a sulfur-based extreme pressure agent or a sulfur-phosphorus-based extreme pressure agent is further added. When it is contained, 0.1 to 10% by weight, preferably 0.1 to 5% by weight is additionally compounded. If the content of each of the compounds other than the sulfur-based extreme pressure agent or the sulfur-phosphorus-based extreme pressure agent is less than 0.1% by weight, it will be difficult to obtain the desired effect, while if it exceeds 10% by weight. , There is no increase in effect. Also, the price becomes high and it becomes impractical.

Since the grease for constant velocity joints of the present invention can reduce the friction coefficient and the induced thrust, it can be used for various constant velocity joints, preferably for automobile constant velocity joints. Among the constant velocity joints for automobiles, it is suitable for use in plunging type constant velocity joints, which have more sliding elements than rolling.

In the constant velocity joint of the present invention, the rotational torque is transmitted by the engagement between the track groove and the rolling element shown in FIG. 1 or 2, and the rolling element rolls along the track groove. This is a plunging type constant velocity joint that is moved in the axial direction, and the above-mentioned grease for constant velocity joint is filled as lubricating grease. Since the plunging type constant velocity joint has much more sliding elements than rolling, the grease for constant velocity joints of the present invention described above is preferably used.

[0029]

EXAMPLES Examples 1 to 8 and Comparative Examples 1 to 4 Diphenylmethane-4,4-diisocyanate 250 in 4000 g of mineral oil (kinematic viscosity at 100 ° C. is 13.5 mm ² / sec)
A base grease was obtained by reacting g (1 mol) with 198 g (2 mol) of cyclohexylamine and uniformly dispersing the produced urea compound. In this base grease,
Additives were added according to the formulation shown in Table 1, and the resulting compound was measured according to JIS Consistency No. It was adjusted to 1 grade to obtain a constant velocity joint grease. Comparative Example 5
Was a lithium soap-based grease containing a sulfur-phosphorus extreme pressure agent as a test sample. The performance of these greases was evaluated by the test method shown below, and the obtained results are shown in Table 1.
Also described in.

[0030] (1) SRV (Schwingung Reibung und Versch) frictions wear test   Test piece: Ball diameter 10mm (SUJ2)                   Cylindrical plate diameter 24mm × 7.85mm (S53C)   Evaluation condition: Load 100 N                   Frequency 15Hz                   Amplitude 1.5 mm                   Time 30min.                   Test temperature room temperature   Measurement item: Average value of friction coefficient (value that became constant within the measurement time)

(2) Induced thrust test Actual tripod type constant velocity joint (NTN: AC
TJ) was used to measure the force generated in the axial direction when rotated by applying an operating angle and torque as induced thrust. Evaluation Criteria: The ratio (%) of the induced thrust to the reference grease, provided that the induced thrust of Comparative Example 5 is 100.

[0032]

[Table 1]

The following materials were used for each additive in Table 1. Additive (1): Molybdenum dithiocarbamate (trade name: Polyvan ART Vanderbilt
(Manufactured by the company) Additive (2): Molybdenum dithiophosphate (trade name: Polyvan LR.T. Vanderbilt
Additive (3): a mixture of dimethyltin bis (isooctyl thioglycol) and monomethyltin tris (isooctyl thioglycol) (trade name: GREC TC-280)
(Manufactured by Dainippon Ink and Chemicals, Inc.) Additive (4): Di (n-octyl) tin bis (isooctyl mercaptoacetate) (Brand name: GREC TO-
248E Dainippon Ink and Chemicals, Inc. Additive (5): Zinc dithiophosphate (trade name: Lubri)
zol 1097 manufactured by Lubrizol) Additive (6): Sulfurized oil and fat (trade name: Lubrizol)
5346 Lubrizol Co., Ltd. Additive (7): Sulfur-phosphorus extreme pressure agent (trade name: Lubr
izol 810 Lubrizol)

As shown in Table 1, each example had a small coefficient of friction measured by the SRV test and a low induced thrust. On the other hand, in each of the comparative examples, since neither component was blended, the friction coefficient was large and the induced thrust was also high.

[0035]

The grease for constant velocity joints of the present invention is
The base grease, which is a base oil containing a thickener, contains an organic molybdenum compound, a sulfur-containing organic tin compound, and an organic zinc compound, so the friction that occurs in constant velocity joints is reduced and vibration is suppressed. You can As a result, the quietness of the automobile is improved. Further, since the sulfur-based extreme pressure agent or the sulfur-phosphorus-based extreme pressure agent is further mixed, the friction generated in the constant velocity joint can be further reduced.

In particular, since each compounding agent is compounded in the above-mentioned predetermined kind and in a predetermined ratio, friction generated in the constant velocity joint is further reduced, vibration is suppressed, and the quietness of the automobile is further improved. To do.

Since the constant velocity joint of the present invention is a plunging type constant velocity joint in which the above grease is enclosed,
Vibration is suppressed sufficiently and the quietness of the car is improved.

[Brief description of drawings]

FIG. 1 is a partially cutaway sectional view of a double offset type constant velocity joint.

FIG. 2 is a partially cutaway sectional view of a tripod type constant velocity joint.

FIG. 3 is a diagram showing an axial force with respect to a rotation angle of a double offset type constant velocity joint.

FIG. 4 is a diagram showing an axial force with respect to a rotation angle of a tripod type constant velocity joint.

[Explanation of symbols]

1, 12 outer ring 2 inner ring 3, 4 track groove 5 balls 6 cages 7,8 spherical surface 9 shaft 10 boots 11 Grease for constant velocity joint 13 track grooves 14 Triport member 15 legs 16 spherical roller 17 Ni dollars

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) C10M 135/06 C10M 135/06 135/18 135/18 135/26 135/26 137/02 137/02 137/04 137 / 04 137/10 137/10 AZ // C10N 10:02 C10N 10:02 10:04 10:04 10:06 10:06 10:08 10:08 10:12 10:12 30:06 30:06 40:04 40:04 (72) Inami Masami Minami, Kuwana-shi, Mie Touhou Oumida 3066 NTN Corporation (72) Inventor Takashi Okanaba 1-4-1, Tsujido-jindai, Fujisawa, Kanagawa Kyodo Yushi Co., Ltd. At the Tsujido Factory (72) Inventor Junichi Imai 1-4-1, Tsujido Shindai, Fujisawa City, Kanagawa Kyodo Yushi Co., Ltd. FA04 FA06 LA03 PA03

Claims (9)

[Claims] 1. A grease for a constant velocity joint, characterized in that an organic molybdenum compound, a sulfur-containing organic tin compound, and an organic zinc compound are added to a base grease obtained by adding a thickener to a base oil. . 2. The grease for constant velocity joints according to claim 1, further comprising a sulfur-based extreme pressure agent or a sulfur-phosphorus-based extreme pressure agent. 3. The base grease is obtained by blending the base oil with a urea thickener.
Alternatively, the constant velocity joint grease according to claim 2. 4. The constant velocity according to claim 1, wherein the organic molybdenum compound is at least one organic molybdenum compound selected from molybdenum dithiocarbamate and molybdenum dithiophosphate. Joint grease. 5. The grease for constant velocity joints according to claim 1, wherein the organozinc compound is zinc dithiophosphate. 6. The base grease according to any one of claims 1 to 5, wherein the thickener is blended in an amount of 1 to 40% by weight with respect to the entire base grease. Grease for quick joints. 7. The organic molybdenum compound is 0.1 to 10
7. The weight percentage, the sulfur-containing organotin compound is 0.1 to 10 wt%, and the organozinc compound is 0.1 to 10 wt%, which are respectively compounded with respect to the entire constant velocity joint grease. Grease for constant velocity joints described. 8. The organic molybdenum compound is 0.1 to 10
% By weight, 0.1 to 10% by weight of the sulfur-containing organotin compound, and 0.1 to 10% by weight of the organozinc compound, and 0.1 to 10% by weight of the sulfur-based extreme pressure agent or the sulfur-phosphorus-based extreme pressure agent.
The grease for constant velocity joints according to any one of claims 2 to 6, which is 10% by weight, and is mixed with the whole grease for constant velocity joints, respectively. 9. A constant velocity joint in which rotational torque is transmitted by engagement between a track groove and a rolling element, and the rolling element rolls along the track groove to move in the axial direction. A constant velocity joint characterized in that the grease enclosed in the constant velocity joint is the grease for constant velocity joints according to any one of claims 1 to 8.