RU2477395C1 - Energy-saving sliding bearing - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: sliding bearing includes a housing and sliding elements mounted on the housing, the sliding surfaces of which have a coating on the basis of nanostructured disperse-strengthened reactivity-sintered silicon carbide (SiC) - 75 - 80 wt % with fibres of silicon nitride (Si₃N₄) - 5 - 8 wt %, fibres of titanium carbonitrides (TiCN) - 2 - 5 wt %, and quasi-crystals of structural scheme of aluminium, copper and magnesium (Al₆Mg₄Cu) - 7 - 18 wt %.

EFFECT: complex improvement of operating characteristics of the bearing owing to reducing power consumption for friction, increasing service life of the bearing operation by several times, which allows using it for different assemblies and mechanisms operating in wide temperature range with high axial and radial loads, and in oxidation and erosion medium.

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Description

The invention relates to plain bearings and can be used in aerospace, oil production, oil pumping, oil refining and other industries.

Plain bearings are widely known. During operation, plain bearings, as a support for a shaft or a rotating axis, receive radial, axial and radial-axial loads from them and provide rotation.

The sliding bearing includes a housing mounted on a shaft journal or axis directly or through a liner or sleeve, and contains mating surfaces between which friction occurs.

To reduce it, plain bearings use antifriction materials, such as alloys based on tin, lead (babbit), copper (bronze), iron (gray cast iron), zinc or aluminum, and plastic (New Polytechnical Dictionary, M., BRE 2000, p. .27).

Known sliding bearing containing a sleeve made with through holes, and antifriction polymer inserts forming protrusions on the inner surface of the friction of the sleeve with a height corresponding to the thickness of the antifriction layer. Antifriction polymer inserts are fixed in threaded through holes of a cylindrical shape (RF patent No. 83303, IPC F16C 33/04, publ. 27.05.2009).

Known liners for sliding bearings from bimetal with an antifriction alloy on an aluminum basis (RF patent No. 2377107, IPC B23K 20/04, publ. 27.12.2009). To obtain inserts, bimetallic sheets or strips of steel are used coated with an aluminum-based antifriction compound with a thickness of more than 6.2 mm.

A heat-resistant coating system is known comprising a plurality of micron-sized ceramic particles of ceramic oxide, or ceramic carbide, or ceramic nitride, or ceramic boride, or metal silicide, or ceramic oxycarbide, or ceramic oxynitride and carbon, which is located on the surface of a designed component selected from a group consisting of a gas turbine component, an aircraft engine component, an internal combustion engine component, and a cutting tool component she (RF patent №2352686, publ. 20.04.2009).

Closest to the proposed one is a sliding bearing, comprising a housing having a cylindrical bore mounted directly on the shaft or axis or through a liner or sleeve, which upon installation form mating surfaces in which friction occurs during sliding, at least one of the mating surfaces has an antifriction coating in the form of a film nanostructured dispersion hardened silicon carbide (RF patent No. 99558, IPC F16C 33/04, publ. 20.11.2010). This antifriction coating in the form of a film nanostructured dispersion hardened silicon carbide allows you to obtain bearings with a friction coefficient of 0.025, which is many times lower than known, but this coating can be used to a limited extent at speeds of about 50-60 thousand rpm and at high dynamic loads due to the low ductility of the material.

Known technical solutions use materials and coatings that improve any one property of a sliding bearing, such as anti-friction, heat-resistant, wear-resistant, etc.

Coated plain bearings that would comprehensively improve the performance of plain bearings have not been identified.

The basis of the invention is the task of comprehensively improving the operational characteristics of plain bearings. The technical result of the invention is a simultaneous substantial decrease in the coefficient of friction, increased wear resistance, hardness, thermal stability, heat resistance, which will ultimately lead to increased energy efficiency of machines, individual industries, industries and the economy as a whole.

The problem is solved in that in the sliding bearing, including the housing and mounted on the housing, at least one sliding element, at least their sliding surfaces are coated on the basis of nanostructured dispersion-strengthened reaction-sintered silicon carbide with silicon nitride fibers and titanium carbonitride and quasicrystals of the structural diagram of aluminum, copper and magnesium of the type Al ₆ Mg ₄ Cu with the following content of components in the coating, wt.%:

silicon carbide 75-80 silicon nitride fibers 5-8 titanium carbonitride fibers 2-5 quasicrystals Al ₆ Mg ₄ Cu 7-18

It is known that fibers of silicon nitride and titanium carbonitride have increased strength and give the composite material an increased level of strength and viscous characteristics, which significantly affects their impact strength and elastic characteristics.

It is also known that quasicrystals are a new class of solids with a structure paradoxical in terms of classical crystallography.

Quasicrystals make it possible to obtain materials with unusual new properties (see, for example, the Wikipedia encyclopedia, http://ru.wikipedia.org/wiki/ Quasicrystals).

To produce an energy-saving sliding bearing according to the invention, silicon carbide and quasicrystals of the structural system: aluminum (Al), copper (Cu) and magnesium (Mg) are crushed to nanostructured dimensions in a known manner, for example, by a vortex vibroacoustic method (see the Federal Internet portal "Nanotechnology and nanomaterials ”, site http://portalnano.ru), then fibers of silicon nitride and titanium carbonitride are added. The percentage of silicon carbide from 75 to 80%, silicon nitride fibers from 5 to 8%, titanium carbonitride fibers from 2 to 5% and Al ₆ Mg ₄ Cu quasicrystals from 7 to 18%. The resulting material in the form of a powder of the nanoscale range is applied to the surface by known methods: either cold gas-dynamic spraying, or gas-spraying spraying. The thickness of the layer of the obtained coating may vary depending on the purpose from 5 μm to 1 mm.

The coating does not require additional physico-chemical treatment (laser, ultrasound, etching in acids, etc.).

The multifunctional coating of the proposed energy-saving sliding bearing allows one to obtain sliding bearings with a friction coefficient from 0.015 to 0.1, a modulus of elasticity of the coating material from 350 to 400 GPa, hardness from 80 to 90 (HRc), and strength up to 1800 MPa. The material properties of the multifunctional coating of an energy-saving bearing, depending on the percentage of ingredients, are presented in the table.

Material Parameters The percentage of ingredients (%) SiC 78% SiC 79% SiC 80% Si ₃ N ₄ 8% Si ₃ N ₄ 7% Si ₃ N ₄ 8% TiCN 5% TiCN 3% TiCN 5% Al ₆ Mg ₄ Cu 9% Al ₆ Mg ₄ Cu 11% Al ₆ Mg ₄ Cu 7% Coefficient of friction 0.1 0.06 0.015 Modulus of elasticity (GPa) 350 380 400 Hardness (HRc) 80 90 88 Strength (MPa) 1750 1780 1800

The stability of the properties is fixed in the range of operating temperatures from -50 to + 1200 ° C.

When designing a sliding bearing, the purpose of the friction unit is usually taken into account by establishing the influence of the determining parameter on the friction coefficient and wear rate, and in accordance with this, the coatings are respectively antifriction, heat-resistant, wear-resistant, etc.

A decrease in the coefficient of friction to 0.015-0.15 confirms that the claimed coating is antifriction.

The stabilization of properties in the specified temperature range (from -50 to + 1200 ° C) and the achievement of the specified + 1200 ° C shows that this claimed coating is a heat-resistant coating.

The stability of the properties in the range of operating temperatures from -50 to + 1200 ° C confirms the thermal stability of the claimed coating.

As can be seen from the data presented, the coating according to the invention has sufficient strength (1500 MPa) with a high modulus of elasticity (400 GPa), and an increased hardness (80-90 HRc) confirms erosion resistance, which allows the sliding bearing to withstand wear. The coefficient of increase in wear resistance in comparison with steel is 20.

Thus, the claimed multifunctional coating comprehensively improves the properties of the bearings, which ultimately allows us to consider it energy-saving, because the cost of overcoming friction is approximately 20 times less than that of bearings made of alloy steels.

The energy-saving sliding bearing according to the invention as a whole allows one to reduce the energy cost of friction and increase the service life of the bearing several times, which allows it to be used for various components and mechanisms operating in a wide temperature range with high axial and radial loads and in an oxidizing and erosive environment.

Claims (1)

A sliding bearing comprising a housing and installed on the housing, at least one sliding element, at least the sliding surfaces of which are coated on the basis of nanostructured dispersion-strengthened reaction-sintered silicon carbide with fibers of silicon nitride and titanium carbonitride and quasicrystals of the aluminum structural scheme , copper and magnesium type Al ₆ Mg ₄ Cu in the following content of components in the coating, wt.%:
silicon carbide 75-80 silicon nitride fibers 5-8 titanium carbonitride fibers 2-5 quasicrystals Al ₆ Mg ₄ Cu 7-18