RU2202601C2 - Average-temperature lubricant for heavily loaded units friction, roller and slider units - Google Patents

Abstract

FIELD: mechanical engineering. SUBSTANCE: lubricant comprises, wt%: graphite 4-15; molybdenum disulfide 3-9; polyisobutylene 2-4; multiple-function admixture - 1,4-di(N-arylsulfonylamino) -2- (thiobenzthiazole)benzene 0.5-5; oil soap thickened oil up to 100. Lubricant is used for lubricating of friction, roller and slider units, such as roller and slider bearings, pivot joints, threaded connections, toothed and other transmissions employed at temperatures of up to 200-250 deg. EFFECT: increased service life of lubricant and provision for operation of friction units under high loads. 2 tbl

Description

The invention relates to lubricants used in heavily loaded friction units, rolling and sliding bearings, in hinges, bearings, threaded joints, gears and other gears, etc. at maximum temperatures up to 200-250 ^o C.

Currently, Litol-24 universal lubricant is widely used, which has a relatively long service life and successfully replaces sodium and lithium general-purpose lubricants. The lubricant has satisfactory extreme pressure characteristics, operates at 110-130 ^o C and can withstand temperatures up to 200 ^o C for a short time. However, in many cases this is not enough for the normal operation of mechanisms and assemblies.

 Litol-24 grease, in addition, is characterized by good conservation properties, it reliably protects metal products from corrosion, can be laid in friction units as an irreplaceable grease, and is a multi-purpose grease. According to its tribological characteristics, Litol-24 refers to lubricants for medium-loaded friction units.

Litol-24 may have a different composition, most often Litol-24 is prepared by thickening a mixture of naphthenic oils with lithium soap 12-hydroxystearic acid. In the manufacture of Litol-24 on a mixture of I-50A oils and spindle AU, a viscosity additive Polyisobutylene P-20 is introduced into the lubricant. The lubricant on a mixture of oils from West Siberian oils (without P-20 additive) is inferior to the lubricant on Baku oils. Composition of Litol-24 grease (GOST 21150-75),%:
Thickener - lithium soap of 12-hydroxystearic acid - 13
Additives: antioxidant diphenylamine - 0.5
or neozone-D - 0.7
Viscous - polyisobutylene P-20 - 4
Dispersion medium - a mixture of spindle oil AU and industrial I-50A (1: 3) or residual or distillate oils of West Siberian oils - Up to 100
Along with many positive characteristics of Litol-24 grease, which makes it multi-purpose, which led to its widespread use in friction units, many of its characteristics do not satisfy more severe operating conditions, which requires modern technology, due to the limited nature of its characteristics. Thus, the main disadvantages of Litol-24 grease are:
- low antiwear and extreme pressure properties at high specific loads, i.e. in heavily loaded knots of rolling and sliding friction, the use of Litol-24 is simply impossible;
- the upper temperature operating range for Litol-24 is 110-130 ^o С and for a short time up to 200 ^o С, in heavily loaded friction units a temperature of about 200 ^o С and sometimes up to 250 ^o С usually develops;
- for modern technology, the life of Litol-24, used as an irreplaceable lubricant, is insufficient (for example, in some automotive friction units for 1-2 years);
- Litol-24 cannot be used for threaded connections and as a heat-resistant lubricant (operating temperature 200 ^o С).

 The basis of the invention is the task of creating a medium-temperature lubricant for heavily loaded rolling and sliding friction units based on soap lubricants of the Litol-24 type, in which with the introduction of graphite, molybdenum disulfide and additives, the antiwear, anti-seize and anti-corrosion properties are significantly increased, and the possibility of using the lubricant for higher temperatures.

 As a prototype, the medium temperature grease according to the patent UA 24433 A, 10.30.1998, which contains thickened petroleum oils, graphite, molybdenum disulfide and a multifunctional additive, is selected as a prototype. As a multifunctional additive, the product of the addition of dimethylphosphite and 1,4- (arylsulfonyl) quinoneimine is used. The lack of additives: in this case, the exact chemical formula of the active substance is not established, which makes it difficult to control the composition of the additive, and ensure the stability of its properties.

The stated technical problem is solved by the fact that the composition of Litol-24 or another lubricant based on Li or NaCa soap additionally contains graphite, molybdenum disulfide and a multifunctional additive, with the following ratio of components, wt.%:
Graphite - 4 - 15
Molybdenum disulfide - 3 - 9
Polyisobutylene, P-20 - 2 - 4
Multifunctional additive - 0.5 - 5.0
Oils thickened with soaps, (for example, finished Litol-24 greases, etc.) - Up to 100
Graphite is the cheapest material available. The lubricant contains the main antifriction filler, which allows for a short-term increase in temperature in the friction unit to 400-450 ^o С to provide a reducing medium that does not allow oxidation of other components of the lubricant. Thus, graphite increases the antiwear, extreme pressure, anti-corrosion properties of the lubricant and increases the operating temperature of the lubricant.

 The optimal amounts of graphite are 6-15 parts by weight, the lower and upper limits are determined by the lubricating properties of graphite and the consistency of the lubricant, which, in turn, is determined by operational requirements. Within these limits, the effectiveness of graphite as an antifriction additive is high.

 Molybdenum disulfide is introduced into the composition of the lubricant as an effective anti-friction additive that improves the working conditions of a heavily loaded friction unit, increases the life of the lubricant, and it becomes possible to use lubricant in threaded joints.

 It is proposed to use polyisobutylene P-20 as a viscosity additive. This additive is added as needed, depending on the base used.

 For example, if Litol-24 is used as a base, an additive is not needed, and if lubricant 1-13 is used as a base, 3-4% of the additive is added.

 The optimal amount of molybdenum disulfide 3-9 wt.h. The lower and upper limits are determined by the lubricating properties of molybdenum disulfide. In this lubricant with a molybdenum disulfide content below 3 parts by weight antifriction properties of the lubricant are sharply reduced, and when the content is above 9 parts by weight they remain virtually unchanged.

 The multifunctional additive is 1,4-di- (N-arylsulfonylamino) -2- (thiobenzothiazole) benzene.

Multifunctional additive improves:
- anticorrosive properties of the lubricant at elevated temperatures;
- extreme pressure and anti-wear properties of the lubricant, especially in heavily loaded units of rolling friction and sliding, which makes it possible to use lubricant in threaded joints.

где R - Н-,-СН₃.The optimal content of multifunctional additives is determined by laboratory tests, its significant effectiveness is manifested when the content is above 0.5 wt. hours, and above 5 parts by weight the growth of antiwear and extreme pressure properties is negligible. The additive has the following structure:

where R is H -, - CH ₃ .

 The proposed additive has anti-corrosion properties.

 To test anti-friction additives, several plastic lubricants were prepared on the basis of the well-known Litol-24 and 1-13 lubricants. Tests are carried out in comparison with Litol-24 and 1-13 lubricants. The studies were performed on a laboratory friction machine SMC-2 according to the block-roller scheme. The diameter of the roller is 50 mm, the friction area is 1 cm, and the angular speed is 330 rpm. As can be seen from table 2, the lubricants, which include the additive, have better antifriction properties compared to Litol-24 and 1-13 lubricants. In addition, they ensure the operation of the friction unit under heavier loads. To test the tribological properties, we took the examples of lubricants given in Table 1.

 The processing of statistical data on the antiwear properties of greases based on Li-, Na-, Ca-soaps, as well as the results of tests of the antiwear properties of the proposed lubricant of various compositions, allows us to state that its antiwear properties are higher than those of Litol-24, 1-13 types, which increases the service life of rubbing steam and as evidenced by examples of the implementation of lubricants.

Lubrication examples
1. Grease 1 based on Litol-24 grease. It was used in the bearings of the rolling mill of AOZT MMMZ at a high temperature of 250 ^o C. A single grease filling in the bearings of the rolling mill ensured the operation of the equipment for three months, which exceeds the life of the traditional lubricant by more than 5 times.

 2. Lubricant 3 based on a plastic fairy tale 1-13 was used at the Kramatorsk cement-slate plant, in bearings of drum kilns with an axle load of 400 tons. The operating time of a bearing with a single grease filling was one year.

 3. Lubricant 2, based on Litol-24 grease, was used to lubricate the cams of the turbine shaft of the Kramatorsk TPP. The life of the friction unit with a single lubrication was three years.

Claims (1)

Medium temperature grease for heavily loaded rolling and sliding friction units, containing oil thickened soap oil, graphite, molybdenum disulfide and a multifunctional additive, characterized in that it contains 1,4-di- (N-arylsulfonylamino) -2- (thiobenzothiazole as a multifunctional additive ) benzene and additionally contains polyisobutylene as a viscosity additive in the following ratio of components, wt.%:
Graphite - 4 - 15
Molybdenum disulfide - 3 - 9
Polyisobutylene - 2 - 4
Multifunctional additive - 0.5 - 5.0
Condensed Oil - Up to 100i

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