WO2001038466A1

WO2001038466A1 - Method of treatment of friction surfaces of friction units

Info

Publication number: WO2001038466A1
Application number: PCT/UA1999/000032
Authority: WO
Inventors: Sergei Nikolaevich Alexandrov; Vladimir Valentinovich Buzov; Elmin Abbas-Ogli Gamidov; Vladimir Leonidovich Zozulya; Sergey Leonidovich Zozulya; Igor Vladimirovich Nikitin
Original assignee: Sergei Nikolaevich Alexandrov; Vladimir Valentinovich Buzov; Gamidov Elmin Abbas Ogli; Vladimir Leonidovich Zozulya; Sergey Leonidovich Zozulya; Igor Vladimirovich Nikitin
Priority date: 1999-11-22
Filing date: 1999-12-28
Publication date: 2001-05-31
Also published as: UA36226A; NZ502653A; AU3096400A; CN1297065A

Abstract

The present invention relates to the methods of treatment of friction surfaces of friction units and is destined for decreasing mechanical losses from friction and increasing longevity of friction units of internal-combustion engine, aggregates and transmission units and machine running gears. The method of treatment of friction surfaces of friction units by forming a covering in the presence of working conditions, which includes feeding of powder in friction zone, the powder, which is prepared out of the natural minerals, which is chosen from the flaky silicate row with addition of catalysts. It is seen from the examples of the offered method realisation, it has more essentially wide functional possibilities, decreases expenses on treatment of the friction surfaces of friction units with use of powders, prepared from natural minerals, by reducing treatment duration, powder expenditure and technological medium.

Description

METHOD Of TREATMENT of FRICTION SURFACES Of FRICTION UNITS

FIELD OF THE INVENTION

The present invention relates to the methods of treatment of friction surfaces of friction units and is destined for decreasing mechanical losses from friction and increasing longevity of friction units of internalcombustion engine, aggregates and transmission units and machine running gears .

BACKGROUND OF THE INVENTION

The problem of increasing wear resistance of friction pairs does not lose its actuality with the necessity of raising quality, reliability and longevity of contemporary machines. It is known that the most machines and mechanisms go out of use because the friction pair details of rolling bearings, sliding, tooth gearing, compressions, spline units, guides and etc. wear off. It is known that making on the friction surfaces hardwearing layers, which permit sharply increase tired solidity, corrosion resistance and wear resistance of materials which work under the contact weary conditions and grating, is one the most widespread ways of rising details longevity nowadays . The making coating thickness or strengthened layer depends on friction unit operating conditions, its setting, predominant wear sort and wear permissible size. The coating thickness can be changed in wide limits: from part of micrometers - for wear resistant coating, till some millimetres - for restoration maintenance of technique. It is also known that it is necessary to pay attention to the row additional economical, technological and constructive factors [ Drozdov U.N., Pavlov V.G., Puchkov V.N. Friction and Wear in extreme conditions. - M. : Mashinostroenie, 1986. - 224 p.; Klamann D. Lubricants and Related Products. Synthesis. Properties. Applications. International Standards. - M. : Himiya, 1988. - 488 p.; Tribologia: Research and Apposition: USA experience and ISU, under red. of Beliy V.A., Ludema K., Mishkin N.K. - M. : Mashinostroenie; New-York: Allerton press, 1993. - 454 p.]. Therefore, the applications of drifting on protecting coating methods by means of coating precipitating or chemistry-thermal treatment of surfaces with the aim of giving necessity characteristics are excluded in many cases. The methods and means which allow forming wear resistant, anti- friction coatings by means of chemical-mechanical or chemical treatment of friction surfaces of friction units are more preference .

It is known strengthening of steel details surfaces method, which includes feeding of saturating mass containing MoS2 and next it is treated by a rubber [ description to author's certificate of the USSR No.1627588, 07.12.88, IPC C 10 V 129/04] . The rubber makes the pressure that provides raising of temperature in treating zone and forming of setting thickness diffusion layer. The famous property of MoS2 coatings to raise the tribotechnical characteristics of coatings from this material is used at present .

Thought the method is distinguished as simple, it can't be used for the complex configuration details treatment. Furthermore it is necessary to have higher temperatures for making MoS2 coating with high tribotechnical characteristics then temperature of oil inflammation. The other deficiency of MoS2 coating is its sensitivity to water. The MoS2 friction coefficient and wear rise in the presence of water.

It is also known the method of making friction surfaces of friction units by means of drifting on friction surfaces solid-lubricant MoS2 coating with thickness 10- 15 mem and by means of feeding in the friction unit of mineral oil with an additive [description to RU patent No. 2049108, 05.05.92, IPC c 10 M 129/40 ] . The additive is the result of the ammonium molybdenumacid with the olein acid.

The above described method of treatment realises three mechanisms of lubrication action simultaneously that leads to synergism of their action both on friction surfaces and in lubrication material volume and increases tribotechnical oil characteristics .

However, it is necessary, to use the additive very carefully as feeding of its above definite quantity leads to decreasing the coating wear resistant characteristics.

Furthermore, it is known the solid-lubricating coating, which consists of powder additive and coupling agent, in which the natural mineral mixture with dispersion not less than 10 mem is used as the powder additive [description to RU patent No. 2043393, 25.09.91, IPC C 10 M 125/04]. The components of used natural mineral are able to form the sliding mirrors and provide a final antifriction fettling at above-mentioned dispersion. The natural mineral mixture consists of Ni, Ti,. Cr, Cu, FeO, S, CaO, MgO, AL203 and, may be, H20.

However, because of the little thickness such coatings are destroyed quickly in the presence of large loads. As it is known after destruction of a coating, which works in initial exploitation period without of wear the tribological characteristics of friction units essentially decrease and are not restored even at the repair-restoration operations, which are inevitable for the friction pairs which are working in the complex thermochemical conditions.

The nearest to declared decision for setting technical essence and the result that must be reached during the use, is the method of treatment of friction surfaces of friction units by means of forming a coating in the presence of working conditions, which includes feeding of powder in friction zone, the powder which is prepared of the natural minerals, which is chosen from the flaky silicate row with addition of catalysts on the basis of schungite and rare earth metals or of mixture this powder with technological medium [ description to the UA patent No. 24442 A, 22.04.97, IPC C 23 C 26/00; C 10 M 125/40 ] . The method is also characterised by powder preparing from the natural minerals or of the mixture of the natural minerals, which consist of the amorphous silicon dioxide. At that the powder dispersion is about 10-30 mu, and its abundance is chosen within the limits of 0,15 to 20% with respect to technological medium.

Above described method permits in a number of cases to restore capacity for work of a friction unit with simultaneous antifriction and wear resistant characteristics rising. However this method connects its characteristics only with powder concentration in technological medium, though it supposes taking into account friction surface technical state. Such approach leads to the unjustified powder expense, the unjustified large duration of forming coating process, and in a number of cases to absence of positive result after treatment and even to decreasing of friction unit state.

SUMMARY OF THE INVENTION

Therefore the task of the offered technical decision is expansion of its functional possibilities, decreasing of the expenses on the treatment of friction surfaces of friction units by means of reducing of treatment duration and powder expense .

The basis of the invention is improvement of the method of treatment friction surfaces of friction units, in which, in c o n s e q u e n c. e of making treatment not less than one - three stages, mounting the quantity of stages and using powder dispersion depending on preliminary inspection of the technical state of friction units and friction surfaces, with taking into account the initial grade of accuracy and cleanliness level of treatment of friction surfaces of friction units, and judging about the results of treatment by means of changing technical characteristics of the mechanisms, which include treatment friction surfaces of friction units, it is p r o v i d e d by filling up bottoms of cavities of the surfaces roughness, which are the result of mechanical treatment, and the bottoms of surface cracks by dispersion fractions, in which the most active interaction of the powder articles with the surface material takes place, and at the e x p e n s e of that the modification of friction surfaces takes place, wear resistant characteristics improve, because the solid of friction surfaces increases and the friction coefficient reduces. Furthermore, as the surfaces modification makes with the volume increasing, at the expense of that the surface restoration and the restoration of technical characteristics of the mechanisms in which treating units work take place.

In c o n s e q u e n c e of use powders with the proper dispersion for friction surfaces, cavities which are made at the time of initial treatment or at exploitation, the optimum conditions are realised for the interaction of powder material and the friction surfaces of friction unit material, and at the e x p e n s e of that the time of surface layer modification is reduced, the damage of a surface by solid powder articles is excluded, the formation of a tease is excluded.

The put problem is solved so that in the known method of treatment friction surfaces of friction units by means of forming a covering in the presence of working conditions, which includes feeding of powder in friction zone, the powder is prepared of the natural minerals, which are chosen from the flaky silicate row with addition of catalysts on the base of schungite and rare-earth metals, or mixture of this powder with technological medium, a c c o r d i n g to the invention, the treatment is fulfilled not less than in one-three stages, the quantity of stages and using powder dispersion are mounted depending on preliminary inspection of technical state of friction units and friction surfaces, with taking into account the initial grade of accuracy and cleanliness level of treatment of the friction surfaces of friction units, and about the results of treating somebody judges by technical characteristics changes of mechanisms, which include treating friction surfaces of friction units.

According to preferred embodiment of the invention for the friction units and friction surfaces, which are treated according to 1-2 grade of accuracy and 8-13 cleanliness level of treatment of friction surfaces, the powder is used with dispersion 0,3-5,0 mu.

According to preferred embodiment of the invention for the friction units and friction surfaces, which are treated according to 2a - 3 grade of accuracy and 7 - 8 cleanliness level of treatment of friction surfaces, the powder is used with dispersion 5,0-20,0 mu .

According to preferred embodiment of the invention for the friction units and friction surfaces, which are treated according to 3 - 4 grade of accuracy and 3 - 7 cleanliness level of treatment of friction surfaces, the powder is used with dispersion 25,0 - 50,0 mu.

The duration of treatment and quantity of the treating stages depend on the wear degree. The grade of accuracy of making friction units determines the size of possible clearances, and the cleanliness level of treatment of friction surfaces determines the sizes of cavities on the friction surfaces. The registration of the two last circumstances permits to exclude teases and to carry out the friction surfaces modification, beginning it at the most advantageous disposition of modification substance particles, namely in the cavities and the cracks of the friction surfaces .

As it is seen from the description of the technical decision, which is declared, it is distinctive from the prior art and, consequently, it is new.

The decision has also the inventive level . It is known utilisation of solid lubricant materials with flaky structure of gratings. Such solid-lubricant materials, as graphite and MoS2 have received the wide application. As well solid-lubricant materials which have the flaky structure are known some chlorides, nitrides, iodides, as well as hard metals sulphides and others. In the most cases they have the flaky hexagonal structure, well antioxidant and chemical stability, electric conductivity and they are used as powders, suspension and antifriction varnish coatings [ Klamann D. Lubricants and Related Products. Synthesis. Properties. Applications. International Standards. - M. : Himiya, 1988. - 488 p.; Tribologia: Research and Apposition: USA experience and ISU, under red. of Beliy V.A., Ludema K., Mishkin N.K. - M. : Mashinostroenie; New-York: Allerton press, 1993. - 454 p.]. It is also known that the solid-lubricant materials with a complex grating structure must have good adhesion to a metal surface and a lubricant coating must be enough hard-wearing (or uninterruptedly be restored) to provide satisfactory longevity.

However the approach of optimal efficiency of above mentioned materials essentially depends on a friction unit construction, its surface preparation to a coating forming and a compatibility friction surface material with a solid lubricant coating material, as temperature, humidity and other exploitation conditions, for example, medium aggressiveness in which a friction surface of friction unit is working, the conditions of friction unit work and etc. the like exert a large influence on friction characteristics of the above mentioned materials.

The proposed method, apparently, permits to realise the making of coating mechanism from the mentioned composition powders, which is analogous of that, which is realised in the presence of the disulphide molybdenum coating drifting. It is known that the disulphide molybdenum coating with thickness up to 0,1 mu has a quasiamorphous structure. At thickness from 0,1 mu to 0,15 mu polycrystalline structure takes place. At thickness 0,15 mu a texture with the axis [1010] origin takes place, that indicates on forming of the grating of the hexagonal type, which becomes brightly pronounced at thickness 0,3 mu . The thickness increasing is conducted by rising of the tribotechnical disulphide molybdenum coating characteristics [ Tribologia: Research and Apposition: USA experience and ISU, under red. of Beliy V.A., Ludema K. , Mishkin N.K. - M. : Mashinostroenie; NewYork: Allerton press, 1993. - 454 p.] .

It is also known that some coatings generated as a result of powder use, which are prepared on the base of the natural minerals, form sliding mirrors, which, apparently, provide unlimited capacity for work, and also wear resistance [description to RU patent No. 2043393, 25.09.91, IPC C 10 M 125/04] .

However the offered method is in principle distinguished from the known methods not only by the permission to treat a friction surface of friction units in the presence of working conditions, providing increasing of friction units tribotechnical characteristics for the friction coefficient decreasing and a friction zone restoration [description to the UA patent No. 24442 A, 22.04.97, IPC C 23 C 26/00; C 10 M 125/40] , but also by the new approach to forming modified surfaces with taking into account the initial grade of accuracy and cleanliness level of treatment of the friction surfaces of friction units. Such approach permits to widen functional possibilities of the method, to reduce the powder expense and to rise the achievement of positive result percent, i.e. makes the method more economically advantageous . These circumstances are more important for treatment of considerable lots both new and especially used equipment .

The offered technical decision may be used in the industry, as it may be widely used in different mechanical engineering branches, and also for different equipment in the system of repair-restoration and operational enterprises.

USE OF THE INVENTION

The control of efficiency of the offered method was done on the equipment of different types, different exploitation period of time by means of comparison of the known method and the offered. In the case of comparison, the equipment was selected of the same model and approximately of the same level of wearing. The results of the method use are shown in the next examples. For all that the powder containing 90 95% ophite, 4,8 - 9,8% schungite, 0,10 0,15% rare-metals, and the rest other natural flaky silicate admixtures were used. As technological medium either basic oil, or kerosene (white spirit) , or fuel (as in a case of plunger pair treatment of a high-pressure fuel pump (FPHP) ) were used.

Describing the examples of the offered method realisation only basic mechanisms and characteristics of friction units, characterising consumer effect, were used.

Example 1. Two fuel pumps were in exploitation for a long period of time and as a result at a moment of treatment the generated pressure was 10 - 12 MPa that corresponded to 50 - 60% of wear. The friction surfaces of friction units of such sort of equipment are treated during manufacture according to 1 - 2 grade of accuracy and 8 - 9 cleanliness level of treatment of friction surfaces. For the treatment of the first pump the powder with ophite dispersion 15 -20 mem was used. The powder abundance in technological medium was 0,8 - 0,85 g/1. After its treatment during 30 hours the pressure made by the pump did not increase, but even decreased to 8 MPa. For treatment of the second pump the powder with ophite dispersion from 0,5 to 3 mem was used. The powder abundance in technological medium was 0,015 - 0,016 g/1. After pumping of technological medium with powder addition during 8 hours the pressure made by pump rose to 30 MPa. Example 2. The negative result was received in the case of the treatment by the known method of the plunger pairs of the high-pressure pumps. For treatment according to the offered method it was taken the plunger pairs of FPHP, with approximate wear was 70% about. On a test bench such plunger pairs provided the measured retort filling with an average speed 4 - 5 ml/min. For the treatment of such plunger pairs it was diesel fuel with powder abundance 0,015 - 0,016 g/1 was used as technological medium. Friction surfaces of such sort of the equipment are treated during the manufacture according to 1 - 2 grade of accuracy and 8 - 9 cleanliness level of treatment of friction surfaces. For the treatment the powder with the ophite dispersion 0,5 - 3,0 mu was used. After treatment during 8 hours the filling speed was 15 - 16 ml/min, that corresponds to passport date of such sort of the equipment .

Example 3. In lubricant system of complex which includes model K-500-61-1 turboblower, the above mentioned composition powder with dispersion 5-10 mu and on the basis of 0,03-0,04 g/1 was introduced in technological medium. In whole the complex wear was 70 - 80% and it was prepared to capital repair. The basic details of the friction units of such complex are treated with the grade of accuracy not less than 2 - 3 and the friction surfaces have roughness not less than 7 - 8 cleanliness level of treatment of friction surfaces. The treatment was carried out in three stages during 8 hours each. As a result of the treatment complex technical characteristics changed as it is shown in the Table 1. Table 1

As it is seen from the Table l, the complex technical state essentially increased and it permitted to continue its exploitation.

Example 4. In the Tables 2 and 3 the comparative test results of two internal-combusting engines with the working cylinder volume 1500 cm3 are brought. The technical state and the method efficiency of the cylinderpiston group were determined by measuring the compression in the engine. The result of inspection showed that the engine wear was approximately 65-70%. Table 2 shows the results of treatment according to the known method. Table 3 shows the results of treatment according to the offered method by above mentioned composition powder.

Table 2

500 6-7 500 6-7

Table 3

Powder Powder Duration of Reached dispersion, abundance in exploitation technical mu technological runnung, efficiency, medium, kg/cm2 g/i km

5-10 0,03 0 5-6 not more 400 7- 8 not more 400 before 10 not more 400 11,5-12,5

As it is seen from Tables 2 and 3, the cylinder-piston group treatment according to the offered method permits to decrease the treatment time and the powder expense. At the same time fuel expense decreases approximately by 15 - 20%, that shows the increasing of tribotecnical characteristics of friction surfaces of friction units.

It should be also added that the tests of the engine treated according to the offered method showed, its use provides the repair reserve making on oil leakage case or loss of oil lubrication properties. The formed modified lawyer provides a possibility to use cylinder-piston group and bearings without lubrication on distance 300 km and more.

Example 5. The toothed pairs of electric locomotive traction motors reduction gearboxes, which consist of large toothed wheel (LTW) and little pinion (LP) , were the object of the offered method application. The toothed pair is formed by means of forging 20HN3A steel with next carbonitriding and surface hardening to HRC 56-64 surface hardness. Such surface treatment is fulfilled not less than 3 - 4 grade of accuracy and not less than 3 - 7 cleanliness level. For checking the offered method the above mentioned tooth pair was placed on the test bench. Table 4 shows the scheme of the method use. The result of method use was defined by wear changing size, which was observed on the toothed pairs toothed wheel and pinion thickness at the placed height of a control measuring device. In Table 4 the average sizes, which were determined as a result of five pairs toothed wheels inspection, are reduced. The kerosene was used as technological medium.

Table 4.

As the data about the use of the known method to such sort of equipment are absent, to make a comparison of the offered method with the known is not possible. However the indubitable result of the use of the offered method is wear decreasing due to restoration of toothed pairs friction surfaces .

Example 6.Taking into account the results of the use of the offered method, which were shown in Example 4, i.e. the possibility of making the so called "repair reserve", the offered method was used for treatment rolling bearing and sliding bearing friction surfaces by means of the mentioned composition without technological medium with the help of rolling on the test bench under exploitation conditions powder thin lawyer drifting. In Table 5 the application method results are shown. The treatment efficiency was determined by means of bearings rolling time measuring till full stoppage. As it is known, rolling bearings and sliding bearings friction surfaces are treated not less than 1 - 2 grade of accuracy (S, SM, M) and not less than 8 - 13 cleanliness level of treatment of friction surfaces.

Table 5

The received results testify about the essential change of friction coefficient from f - 0,1 - 0,2, which corresponds to rather poor lubrication till f = 0,001 - 0,01, which corresponds to oil friction. Besides, after the treatment by the offered method the clearance and the roughness decreasing are observed and correspond to grade of accuracy and cleanliness level rising. The last result shows that the offered method may be used for rising grade of accuracy and cleanliness level of friction surfaces of new goods, that can essentially reduce their cost by means of reducing treatment time.

So, as it is seen from the examples of the offered method realisation, it has more essentially wide functional possibilities, decreases expenses on treatment of the friction surfaces of friction units with use of powders, prepared from natural minerals, by reducing treatment duration, powder expenditure and technological medium.

Claims

PATENT CLAIMS

1. The method of treatment of friction surfaces of friction units by forming a covering in the presence of working conditions, which includes feeding of powder in friction zone, the powder, which is prepared out of the natural minerals, which is chosen from the flaky silicate row with addition of catalysts on the basis of schungite and rare-earth metals or mixture of this powder with technological medium, characterised that the treatment is fulfilled not less than in one - three stages, the quantity of stages and dispersion of the used powder are determined depending on the preliminary inspection of technical state of friction units and friction surfaces, taking into account the initial grade of accuracy and cleanliness level of treatment of friction surfaces of friction units, and about the results of treatment one can judge by changes of technical characteristics of mechanisms, which include the treated friction surfaces of friction units .

2. The method of treatment of friction surfaces of friction units to claim 1 characterised that for the friction units and friction surfaces that are treated according to 1-2 grade of accuracy and 8-13 cleanliness level of treatment of friction surfaces, the powder with dispersion 0,3-3,0 mu is used.

3. The method of treatment of friction surfaces of friction units to claim 1 characterised that for the friction units and friction surfaces that are treated according to 2-3 grade of accuracy and 7-8 cleanliness level of treatment of friction surfaces, the powder with dispersion 5,0-20,0 mu is used.

4. The method of treatment of friction surfaces of friction units to claim 1 characterised that for the friction units and friction surfaces that are treated according to 3-4 grade of accuracy and 5-7 cleanliness level of treatment of friction surfaces, the powder with dispersion 25,0-50,0 mu is used.