WO1994003565A1

WO1994003565A1 - Grease for roller bearings and grease-sealed roller bearing

Info

Publication number: WO1994003565A1
Application number: PCT/JP1993/001097
Authority: WO
Inventors: Hiroshi Komiya; Toshikazu Kouno; Masayuki Kitamura; Toshihiro Kawaguchi; Seiji Okamura; Hiroki Iwamatsu
Original assignee: Koyo Seiko Co., Ltd.; Nippon Grease Co., Ltd.
Priority date: 1992-08-05
Filing date: 1993-08-02
Publication date: 1994-02-17
Also published as: JP3512183B2; DE4397754B4; DE4393753T1

Abstract

This invention relates to grease for roller bearings which contains poly-α-olefin synthetic oil or diphenylether synthetic oil, urea thickening agent, and organic antimony compound or organic molybdenum compound; and a roller bearing in which this grease is sealed. The organic antimony compound or organic molybdenum compound reacts with the rolling surfaces of the inner and outer races and the surfaces of rolling elements in the bearing to form compound films which contribute to the reduction of the tangential force, and to prevent the generation of an excessively large tangential force during the high-speed rotation of a rotary part. This enables the lifetime of a roller bearing, which is used, especially, under severe conditions, to be prolonged.

Description

Specification

Rolling bearings with grease and grease for rolling bearings

The present invention relates to a grease-enclosed rolling bearing used under severe conditions such as high temperature, high-speed rotation, and high load, and a grease for a rolling bearing sealed in the rolling bearing.

Background technology)

For example, rolling bearings used under severe conditions such as high temperature, high speed rotation, and high load, such as around an automobile engine, have recently become more and more severe as operating conditions become more severe, such as high speed rotation and increased load. There is a problem that the fatigue life is reached in a much shorter time than the estimated life time.

Recent studies have clarified that the cause is not the life of the grease sealed in the rolling bearing, but the rolling bearing itself. In other words, during high-speed rotation, excessive tangential force is generated between the rolling elements and the rolling surfaces of the inner and outer races with slippage, whereby the rolling bearing reaches its fatigue life early.

In order to reduce the tangential force applied to rolling bearings, efforts have been made to select a grease lubricating base oil that is suitable for the conditions of use and that can exhibit maximum lubrication performance under high-temperature, high-speed rotation conditions. At present, simply selecting a lubricating base oil is no longer able to adequately cope with increasingly severe use conditions.

The present invention provides a grease for a rolling bearing which prevents a rolling bearing used under particularly severe conditions from reaching a fatigue life early and enables a longer life of the rolling bearing. It is an object of the present invention to provide a long-life grease-enclosed rolling bearing that does not reach fatigue life early even when used.

The grease for a rolling bearing of the present invention comprises a lubricating base oil containing at least a polyolefin-based synthetic oil or a diphenyl ether-based synthetic oil, a urea-based thickener, an organic antimony compound and an organic molybdenum compound. It contains at least one of them. The grease-sealed rolling bearing of the present invention incorporates the above-described grease for a rolling bearing.

According to the rolling bearing grease and grease-encapsulated rolling according to the present invention, an organic antimony conjugate or molybdenum dithiocarbamate typified by antimony dithiocarbamate added to grease as an antiwear agent The organic molybdenum compound, which is represented by the following formulas, reacts with the rolling surfaces of the inner and outer races of the bearing and the surfaces of the rolling elements to form a compound film that contributes to the reduction of tangential force. Prevents generation of excessive tangential force.

In addition, a polyolefin-based synthetic oil or diphenyl ether-based synthetic oil as a lubricating base oil and a urea-based thickener maximize the properties of the above-mentioned organic antimony compounds and organic molybdenum compounds, while rolling. A grease with optimal lubrication performance for the operating conditions of the bearing is constructed.

Therefore, according to the present invention, it is possible to prevent a rolling bearing used under particularly severe conditions from reaching its fatigue life early and to extend the life of the rolling bearing.

BEST MODE FOR CARRYING OUT THE INVENTION>

In the present invention, examples of the organic antimony compound used as an antiwear agent include the following general formula (1):

R ¹ S

\ II

N-C-S S b (1)

/

Three

(Wherein R ¹ and R ² are the same or different and represent a hydrogen atom, an alkyl group or an aryl group.) An antimony dicarbamate represented by the following general formula (2):

R ³ 〇ヽ s

P-S S b (2)

R ⁴ 1 0 3

(Wherein R ³ and R are the same or different and each represent a hydrogen atom, an alkyl group or an aryl group.). Specific examples of the antimony dicarbamate represented by the general formula (1) include, for example, rVANLUBE 73 J (trade name, manufactured by RVanderbilt Company, Inc.). Specific examples of the antimony dithiophosphate represented by the general formula (2) include, for example, a product name “RTVanderbilt Company, Inc.” (RTVanderbilt Company, Inc.). V ANLUBE 622J and the like.

Examples of the organic molybdenum compound include, for example, the following general formula (3):

(Wherein R ⁷ and R ⁸ are the same or different and each represent a hydrogen atom, an alkyl group or an aryl group.), And molybdenum dithiophosphate.

Specific examples of the molybdenum dithiocarbamate represented by the general formula (3) include rMOLYVAN AJ, a product name of LT.Vanderbilt Company, inc., And the like. Specific examples of the molybdenum dithiophosphate represented by the general formula (4) include, for example, the product name `` M0LYVAN LJ '' manufactured by RTVanderbilt Company, Inc. .

These compounds may be used alone or in combination of two or more.

Addition of the above-mentioned organic antimony compounds and organic molybdenum compounds as antiwear agents The addition amount is not particularly limited in the present invention, but is preferably about 0.1 to 5% by weight of the total amount of the lubricating base oil which is the main component of the grease and the thickener. If the amount of the wear inhibitor added is less than 0.1% by weight, it may not be possible to form a compound film capable of sufficiently reducing the tangential force on the rolling surfaces of the inner and outer rings of the bearing and the surfaces of the rolling elements. Conversely, if the added amount of the antiwear agent exceeds 5% by weight, not only the additional effect cannot be expected, but also the economic effect may be disadvantageous.

As a compound similar to the above antimony dicarbamate and molybdenum dithiocarbamate, the following structural formula (5): r 5 H 11 o

\ II

N-C-S (5)

Zinc dithiocarbamate represented by 5H112 is generally known. However, these cannot be used as an antiwear agent in the present invention because a compound film having a sufficient thickness cannot be formed under severe conditions such as high temperature, high speed rotation, and high load. However, since zinc dithiocarbamate has a function as an antioxidant, it may be used in combination as long as the action of the organic antimony compound or the organic molybdenum compound is not inhibited.

As the lubricating base oil, one containing at least a polyolefin-based synthetic oil or a diphenyl ether-based synthetic oil is used. The lubricating base oil containing at least a polyolefin-based synthetic oil or a diphenyl ether-based synthetic oil as described herein includes, in addition to those whose total amount is one of the above-mentioned synthetic oils, a mixture of both synthetic oils It is also possible to use a mixture of both synthetic oils, to which mineral oil and other synthetic oils are added. Other synthetic oils include, for example, polybutene synthetic oils, polyalkylene glycol-based synthetic oils, polyol ester-based synthetic oils, diester-based synthetic oils, silicone-based synthetic oils, and polyphenylether-based synthetic oils other than diphenylether-based synthetic oils. Conventionally known synthetic oils such as oils can be used. The blending amount of mineral oil and other synthetic oils may be about the same as that of conventional grease mainly composed of polyolefin-based synthetic oil or diphenyl ether-based synthetic oil. Specifically, the proportion of other base oils should not exceed 30% by weight of the total base oil. Lower is preferred.

As polyolefin synthetic oils, various oils having various degrees of polymerization can be used, and those having a viscosity suitable for the conditions of use (particularly the temperature of use) can be selected and used. Is done. As the diphenyl ether synthetic oil, those having various molecular weights can be used, and among them, those having a viscosity suitable for the use conditions (especially the use temperature) are selected and used.

As a thickening agent, a rare-type thickening agent is used. Among them, a diurea-based thickening agent is particularly preferable.

The diurea thickening agent has the following general formula (6):

H 〇 H H 0 H

I II I I II I

NCNR ¹⁰ -NC- R 11 (6)

(In the formula, a diisocyanate residue is shown, and R ⁹ and R ¹¹ are the same or different and represent an amine residue.) The diisocyanate is represented by the following reaction formula. It is produced by reacting compound (7) with an amine compound (8) (9).

OCN-R ¹⁰ -NCO (7)

+

R ⁹ -NH ₂ (8)

+

R ¹⁰ — NH ₂ (9)

H 〇 H H 〇 H

I II I I II I

R ⁹ -N-C-N-R ¹⁰ -N-C-N-R ¹¹ (6)

(R ⁹ , R ¹⁰ and R ¹¹ in the above formula represent the same groups as described above.)

The above reaction is preferably carried out in a lubricating base oil, whereby a highly uniform reaction product is obtained. Specifically, a diisocyanate compound (7) and an amine compound (8 ) And (9) were separately dissolved in a lubricating base oil to prepare a diisocyanate solution and an amine solution, respectively, and while stirring one of them, the other was gradually added, and the diisocyanate compound (7) and Reaction with the amine compounds (8) and (9) to form a diurea compound. Alternatively, the amine compounds (8) and (9) may be separately dissolved in a lubricating base oil to prepare two amine solutions, which may be mixed and reacted with a diisocyanate solution.

Next, the reaction solution was heated to about 130 to 210, preferably about 140 to 190 ° C. while stirring, and the temperature was raised, and the temperature was maintained for about 15 to 40 minutes. Thereafter, the mixture is gradually cooled to 120 ° C. or lower, preferably to room temperature, and further kneaded using a homogenizer, a three-stage roll, or the like, so that a grease composition in which the produced diurea compound is uniformly dispersed in a lubricating base oil. Is obtained.

The anti-wear agent and other additives are desirably added after the completion of the above reaction.However, a component which does not inhibit the reaction between the disocyanate compound (7) and the amine compound (8) (9) is added to any of the components before the reaction. Can also be added to the solution.

Preferable examples of diurea-based thickeners include 4,4'-diphenylmethanedi-cysocyanate, alkylphenylenylamines having 8 to 16 carbon atoms in the alkyl moiety, such as p-dodecylaniline, and cyclohexane. Examples of the reaction product include a reaction product of xylamine and a reaction product of 4,4′-diphenylmethanediisocyanate, stearylamine, and oleylamine. In particular, the reaction products of the former, 4,4'-diphenylmethanediisocyanate, alkylphenylamine and cyclohexylamine, do not soften rapidly under high temperature conditions, and they are fibers during high-speed rotation. Since there is no danger of scattering in the state, it is most preferably used in the present invention as it can be used stably for a long period of time under high-temperature, high-speed rotation conditions (Japanese Patent Laid-Open No. 61-155549). No. 6).

The amount of the urea-based thickener is not particularly limited in the present invention, and can be appropriately changed according to grease use conditions and the like. Usually, the urea-based thickener is added to 100 parts by weight of the base oil. May be about 0.3 to 30 parts by weight.

The grease for a rolling bearing of the present invention contains various conventionally known additives such as an antioxidant, an antioxidant, an extreme pressure agent such as a polish borate, and the like in the same amount as before. May be.

The grease-enclosed rolling bearing of the present invention is manufactured by sealing the above-described grease for a rolling bearing of the present invention. The type of the rolling bearing is not particularly limited in the present invention, and the configuration of the present invention can be applied to conventionally known various types of rolling bearings. The amount of grease for rolling bearings can be appropriately changed according to the type and dimensions of the rolling bearings, but may be substantially the same as in the past.

Hereinafter, the present invention will be described based on Examples and Comparative Examples.

Example 1

A polyhistidine Orefuin as lubricating base oil (viscosity at 1 0 0 ^e C 8 Yuzuru ² / S) 8 in 5 0 g, of 1 2 8 g as Amin component p- dodecyl Ryo aniline and 5 0 g Shi Chlohexylamine was mixed and heated to 100 ° C. with stirring to prepare an amine solution.

Separately, 122 g of 4,4′-diphenylmethane diisocyanate as an isocyanate component was mixed with 85O g of the same polyolefin as described above, and stirred while stirring. The solution was heated to 0 ° C to prepare an isocyanate solution.

Then, while stirring the isocyanate solution, the amine solution was gradually added, and the amine component and the isocyanate component were allowed to react with each other to generate a diurea compound in the poly-α-olefin.

Next, the resulting diurea compound is uniformly dispersed in the polyolefin, and the reaction solution is heated with stirring to 15 (the temperature is raised to TC and maintained at 150 ° C. for 15 to 40 minutes). After that, the mixture was gradually cooled to room temperature.

Then, while continuing to stir, an antimony dicarbamate wherein R ¹ and R ² in the general formula (1) are both alkyl groups (products manufactured by RT Vanderbilt Company, Inc.). Name “VAN LUBE 7 3 j” Add 40 g, 40 g of an amine-based antioxidant and 40 g of the same antioxidant, and further treat with a three-stage roll to obtain a rolling bearing. Grease was manufactured.

Example 2

Example 1 was repeated except that the amount of antimony dicarbamate added was 2 g. In the same manner, grease for a rolling bearing was manufactured.

Example 3

In place of antimony dicarbamate, molybdenum dicarbamate wherein R ⁵ and R ⁶ in the general formula (3) are both alkyl groups [manufactured by RT Vanderbilt Company, Inc.] A grease for a rolling bearing was manufactured in the same manner as in Example 1 except that 40 g of the product name “M0L YVAN Aj” was used.

Example 4

As the lubricating base oil, the same amount of alkyl diphenyl ether (having a viscosity of 12 mm ² / S at 100 ° C.) was used in place of poly-α-olefin, and instead of antimony dicarbamate, Molybdenum dithiophosphate in which R ⁷ and R ⁸ in the general formula (4) are both alkyl groups [trade name “MO L YVAN Lj” manufactured by RT Vanderbilt Company, Inc. 4 A grease for a rolling bearing was manufactured in the same manner as in Example 1 except that 0 g was used.

The procedure was carried out except that 150 g of stearylamine and 51 g of oleylamine were used as the amine components, and the added amount of 4,4′-diphenylmethanediisocyanate was 96 g as the isocyanate component. In the same manner as in Example 1, grease for a rolling bearing was manufactured.

Example 6

As a lubricating base oil in place of the poly Orefin, except that the alkyl diphenyl ether of the same amount (1 0 0 ° viscosity at C 1 2 negation ² ZS) was used, in the same manner as in Example 1 rolling bearing Grease was manufactured.

Example 7

A grease for a rolling bearing was manufactured in the same manner as in Example 6, except that 40 g of the same molybdenum dicarbamate used in the actual leak 3 was used instead of the antimony dicarbamate.

Example 8

Instead of antimony carbohydrate, the same molybdenum used in Example 3 Rolling bearing grease was produced in the same manner as in Example 6, except that dendithiocarbamate 20 and 20 g of the same molybdenum dithiophosphate used in Example 4 were used.

Comparative Example 1

A grease for a rolling bearing was manufactured in the same manner as in Example 1 except that antimony dicarbamate was not added.

Comparative Example 2

Instead of antimony dicarbamate, zinc dicarbamate represented by the structural formula (5) [trade name “VAN LUBEAZ” manufactured by RT Vanderbilt Company, Inc.] 4 A grease for a rolling bearing was manufactured in the same manner as in Example 1 except that Og was used.

Comparative Example 3

A grease for a rolling bearing was manufactured in the same manner as in Example 1 except that 40 g of a potassium baud rate was used instead of antimony dicarbamate. The degree of miscibility of the greases for rolling bearings of the above Examples and Comparative Examples was measured according to the method of measuring the degree of miscibility described in JIS K2220 “Grease”. Tables 1 and 2 show the results of the example, and Table 3 shows the results of the comparative example.

The greases for the rolling bearings of the above Examples and Comparative Examples were each sealed in radial ball bearings with both shields (nominal number 6303 Ζ 2) in an amount of 2 g, and the following tests were performed. . The results are also shown in Tables 1 to 3.

Traction coefficient measurement

Using a four-cylinder rolling friction tester, the traction coefficient was measured under the conditions of a load of 23 KN, a rotation speed of 1500 rpm, and a slip rate of 1%.

Measurement of bearing life

Radial ball bearings containing bearing grease were operated for 1000 hours under high-speed, high-load conditions, and the time required for the bearing to break due to separation on the raceway surface was measured. The measurement was performed four times using four radial ball bearings for each sample.

Operating conditions

Number of revolutions: 1800 rpm Radial load: 25 Okg

Temperature: 90 ° C

Rated load C: 13.5KN

In Tables 1 to 3 below, the symbols in each column correspond to the following compounds. <PAO: Polyolefin

ADE: Alkyl diphenyl ether

MD I: 4, 4 'diphenylmethane diisocyanate

PDA: p—dodecylaniline

CHA: Cyclohexylamine

StA: Stearyl Lamine

Or A: Oleilamine

SbDTC antimony dicarbamate

MoDTC molybdenum dicarbamate

oDTP molybdenum dithiophospho

ZnDTC zinc dicarbamate

KBR: Possemble baud rate

table 1

Example 1 Example 2 Example 3 Example 4

PAO 1 700 1 700 1 700

Oil ADE 1 7 η π

MD I 1 1 9 1 9 1 o Increase PDA 1 o 1 9 8 1 ί 9 o Q 19 fi

Yo, CHA 50 50 50 50,

Agent St A

In

Or A

Anti-wear agent SbDTC SbDTC MoDTC MoDTP

40 2 40 40 _ Consistency (60work) 272 269 275 265 Traction coefficient 0.042 0.048 0.0445 .049

1 000 1 000 1 000

(剝 Sfe 1 000

） No separation なし No separation なし No separation なし No separation

Table 2

Example 5 Example 6 Example 7 Example 8

PAO 1 70 0

Oil ADE 1 i 71 Λ υ Π u 1 7 n n 1 7 Λ Π

MD I y D 1 Δ Δ 1 ϊ Δ ο Δ ο 1 ϊ Δ o Δ increase PDA 1 Ο 0 1 Ο 0 1 Ο

Yo, CHA 5 0 50 5 0

Agent St A 1 5 3

In

Or A 5 1

Anti-wear agent SbDTC SbDTC MoDTC MoDTC 20

40 4 0 4 0 MoDTP 20 Consistency (60work) 275 25 0 262 24 8 Traction coefficient 0.043 0.047 0.048 0.047

1 0 00 1 000 1 000 1 000

(剝桑) なし No separation なし No separation なし No separation なし No separation

Table 3

From the results in Tables 1 to 3 above, Comparative Example 1 in which the organic antimony compound and the organic molybdenum compound were not added, and Comparative Example 2 in which zinc dithiocarbamate as the organic zinc compound was added, and Po The bearing to which grease was added in Comparative Example 3 to which evening spray was added was damaged in a very short time. On the other hand, the bearings to which the greases of Examples 1 to 5 were added did not break during 1000 hours.

In addition, comparing the results of Examples 1-3 and 5 and Comparative Examples 1-3 where the same polyolefin was used as the lubricating base oil, it was found that the addition of the organic antimony compound or the organic molybdenum compound could lower the truncation coefficient. I understood.

Based on the above facts, organic antimony compounds and organic molybdenum compounds react with the rolling surfaces of the inner and outer races of the bearing and the surfaces of the rolling elements to contribute to the reduction of tangential force. It was confirmed that a compound film was formed.

Also, comparing the results of Examples 1 and 2 in which the same antimony dicarbamate was added, although the traction coefficient slightly changed depending on the amount of addition, it was found that the life of the bearing itself was not significantly affected. understood.

In addition, comparing the results of Examples 1 and 5 in which the same amount of antimony dicarbamate was added, the grease for bearings had almost the same performance even when the type of urea thickener was different. Was found.

Also, from the results of Example 3, it was found that even if antimony dicarbamate was replaced with the same amount of molybdenum dicarbamate, the grease for bearings had almost the same performance.

Further, from the results of Example 4, it was confirmed that even if the type of the lubricating base oil was different, the life of the bearing could be extended by adding the organic molybdenum compound.

Claims

The scope of the claims

1It must contain at least a lubricating base oil containing a polyolefin-based synthetic oil or a diphenyl ether-based synthetic oil, a urea-based thickener, and at least one of an organic antimony compound and an organic molybdenum compound. Characteristic grease for rolling bearings.

2. The organic antimony compound has the following general formula (1):

(Wherein R ¹ and R ² are the same or different and represent a hydrogen atom, an alkyl group or an aryl group). The grease for a rolling bearing according to claim 1, wherein the grease is an antimony dicarbamate.

3. The organic antimony compound has the following general formula (2):

R ⁴

(Wherein R ³ and R ⁴ are the same or different and represent a hydrogen atom, an alkyl group or an aryl group). The grease for a rolling bearing according to claim 1, wherein the grease is an antimony diphosphate.

4. The organic molybdenum compound has the following general formula (3):

R ¹

(Wherein R ⁵ and R ^e are the same or different and each represent a hydrogen atom, an alkyl group or an aryl group, and m, X and y each represent an arbitrary number.) A molybdenum dithiocarbamate represented by the following formula: The grease for rolling bearings according to item 1.

5. The organic molybdenum compound has the following general formula (4)

R ⁷ 1 〇 S

P-S M 02 〇2 S; (4)

R ⁸ 100

(Wherein RR ⁸ is the same or different and represents a hydrogen atom, an alkyl group or an aryl group.) The grease for a rolling bearing according to claim 1, which is a molybdenum dithiophosphate.

6. The urea thickening agent has the following general formula (6):

H 〇 H H 0 H

I II I I II I

R ⁹ — N— C— N— R ¹⁰ — N— C— N— R ,, (6)

(Wherein R ^lfl represents a diisocyanate residue, and R ⁹ and R ¹¹ represent the same or different amine residues.) The rolling agent according to claim 1, which is a diurea-based thickening agent represented by the formula: Grease for bearings.

7. The grease for a rolling bearing according to claim 6, wherein the diurea thickening agent is synthesized by reacting 1 mole of a diisocyanate compound with 2 moles of an amine compound in a lubricating base oil.

8. The grease for a rolling bearing according to claim 1, wherein the polyolefin-based synthetic oil is polyolefin.

9. The grease for a rolling bearing according to claim 1, wherein the diphenyl ether-based synthetic oil is an alkyl diphenyl ether.

10. The rolling bearing according to claim 1, wherein the addition amount of at least one of the organic antimony compound and the organic molybdenum compound is 0.1 to 5% by weight of the total amount of the lubricating base oil and the thickener. Grease.

2. The grease for a rolling bearing according to claim 1, wherein the amount of the urea-based thickening agent is from 0.3 to 30 parts by weight per 100 parts by weight of the base oil.

1 2. A grease-enclosed rolling bearing characterized by enclosing the grease for a rolling bearing according to claim 1.