SU1696771A1 - Plain bearing - Google Patents

Abstract

The invention relates to mechanical engineering, namely, to sliding bearings with an antifriction layer based on siliconized graphite, operating under dynamic and periodic shock loads under difficult conditions of imperfect lubrication, viscous, chemically active liquids. The goal is to increase the wear resistance and life of the bearing by increasing the impact strength of the antifriction layer when lubricating it with oils and chemically active low viscosity media. The sliding bearing (PS) consists of a fixed and fixed on the shaft movable sleeves, the working surfaces of which are coated with an antifriction material based on siliconized graphite. The antifriction coating material contains a mixture of powders of siliconized graphite and titanium carbide on nickel-clad in the following ratio of components. wt.%: titanium carbide 20-25; nickel 12-52; siliconized graphite else. The introduction of nickel-plated silicon carbide into the material significantly increases the corrosion resistance of the antifriction layer in chemically active media. Improving the elastic and strength parameters of the coating of PS without deteriorating its anti-friction properties allows one to approximate the mechanical characteristics of the coating and the coating. 1 ill., 1 tab.

Description

The invention relates to mechanical engineering, specifically to sliding bearings with a siliconized graphite-based emulsion-based layer, operating under dynamic and periodic shock loads, under difficult conditions of imperfect lubrication, viscous, chemically active

LIQUIDS.

The purpose of the invention is to increase the wear-resistant ™ and the service life of the bearing by increasing the impact strength of the antifriction layer when lubricating it with oils.

and chemically active low viscosity media.

Due to the uniform distribution of particles of siliconized graphite and titanium carbide in the form of grains in a soft matrix, the role of which is played by nickel, the impact strength of the material increases significantly compared with the toughness of pure ceramics.

Additional introduction of titanium carbide in a known material (siliconized graphite), which is made of

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VI

an antifriction bearing layer, and the cladding of nickel particles from a mechanical mixture of powders of siliconized graphite and titanium carbide significantly increases the toughness and wear resistance of the antifriction slip bearing layer, operating under lubrication conditions with oils and chemically active low viscosity media.

Silicon carbide, which is a part of siliconized graphite, has a microhardness of 2800 kg / mm2, and titanium carbide - 3200 kg / mm, and the era arrangement in the form of grains (friction composition 20-100 µm) fixed in a soft matrix Nickel significantly increases the impact resistance and wear resistance of the antifriction layer, including corrosion resistance and resistance in chemically active media, since titanium carbide has good resistance in alkaline and some acidic environments.

The introduction of less than 20% by weight of titanium carbide into the composition of the material does not significantly affect the increase in wear resistance. With the introduction of more than 25 wt.% Of titanium carbide into the composition of the material, the properties of the bearing bearing wear pattern also do not change.

The introduction of nickel a in the amount of 12–52 wt.% Into the material of the material from which the antifriction bearing layer is made in the form of shells around the core consists of particles of a mechanical mixture of powders of silicified graphite and titanium carbide, which makes it possible to create a uniformly distributed nickel matrix. structure of silicon carbide, and therefore increase the impact strength and wear resistance of the antifriction layer, including corrosion resistance, because nickel is resistant and weak solutions of acids and alkalis.

The presence of free carbon in the vi material, its uniform distribution from the nickel matrix ensures the short-term operation of the friction pair when the lubricant supply is stopped due to the effect of lubrication, which means that the wear resistance of the antifriction layer increases.

In addition, when a powder of antifriction material is applied to the working surface of a sliding bearing bearing cartridge with concentrated sources of energy, such as a plasma jet, a nickel shell protects the particle cores from burnout of its components,

therefore, it prevents from changing the composition of the antifriction layer.

A nickel content of less than 12% by weight reduces the impact strength of the antifriction layer, since in this case the thickness of the nickel sheath around the core of a mixture of siliconized graphite and carbide. titanium is insignificant. The antifriction layer is obtained with a stiffer silicon carbide structure. In addition, a partial burnout of the components of the anti-friction material may occur. Impact strength and wear resistance are impaired. Increased nickel content (over 52

wt.%) reduces the wear resistance of the antifriction layer, impairs & antifriction properties of the coating, since under conditions of imperfect lubrication, the materials of a friction pair may set

lower specific loads.

Thus, the anti-friction layer deposited on the working surface of the bearing sleeve shows an increased adhesion to the sleeve material due to the enhanced adhesive properties of the anti-friction material. Improving the elastic and strength parameters of the coating (without reducing its anti-friction properties) allows one to approximate the mechanical characteristics of both the coating and the bushings, which ensures their reliable joint operation.

The sketch shows a radial sliding bearing mounted on the shaft of a sealed pump.

The bearing consists of a fixed sleeve 1 installed in the pump housing 2 and a movable sleeve 3 rigidly mounted on the shaft 4. The antifriction layer is applied to the inner surface of the fixed sleeve 1 and the outer surface of the movable sleeve 3, respectively, 5 and 6. The antifriction layer is applied with using plasma

sprayed from a material that is a powder composition of siliconized graphite and titanium carbide in a nickel sheath.

During the rotation of the rotor room 4, the working surface of the sleeve 3, is coated with an anti-friction layer 5, slides over the anti-friction layer 5 of the stationary sleeve 1.

8 strength of surface hardness

the antifriction layer of the bearing is greater than the hardness of particles that may fall into the gap between layers 3 and 6, the coarse particles are crushed, not embedded in the coating, and washed out with a wetting liquid, not

destruction of the working surfaces of the antifriction layers 5 and 6.

The evaluation of the effect of the percentage composition of components (nickel, titanium carbide and siliconized graphite) on the increase of the service life of sliding bearings by achieving optimum values of impact resistance and wear resistance in the reinforcement coating was carried out on a special test bench for axial bearings. Tap water with a temperature of t 298 ± S K was used as the lubricating fluid. The sliding speed during the tests was 15.7 m / s. The specific load is 0.98 MPa.

The test time for one start-stop cycle was 1 minute, of which 20 seconds was start-up, work under load, stop and AO c-cooling of the working surface.

The test results are summarized in

Testing has shown that the sliding bearing has increased toughness and wear resistance and can be widely used in electric pumps operating in low viscosity chemically active media, in environments with a high content of mechanical impurities and in dynamic and periodic shock loads.

Claims (1)

Invention Formula A sliding bearing consisting of a fixed and fixed on the shaft movable sleeves, the working surfaces of which are coated with an antifriction material based on siliconized graphite, characterized in that in order to increase the wear resistance and the service life of the bearing by increasing the impact strength of the antifriction layer when lubricating it with oils and chemically active low viscosity media, the antifriction material additionally contains titanium carbide, while the mixture of powders of siliconized graphite and titanium carbide is plated Nickel in the following ratio of components antifriction material, May. %: Titanium carbide 20-25; Nickel 12-52; Silicon Graphite Else Note. Impact viscosity of pure siliconized graphite SG-T was 2.7 kJ / w, pure nickel - 39 kJ / m