RU136777U1 - BRAKE SUSPENSION BUSH FOR RAIL TRANSPORT - Google Patents

Abstract

The suspension shoe of the brake shoe for rail transport refers to the production of bushings with a low coefficient of friction, and can be used in all types of rail transport: in passenger and freight railway trains, trams, subway trains. The sleeve is made of a composite material containing a urethane prepolymer of SIC-PU-5 grade as a fibrous filler, powder graphite of grade P as a release agent and a cross-linking agent of SIC-PU-5 grade as a binder, in the following ratio, wt. %:

Urethane prepolymer NITs-PU-5 75.0-77.5 Powder graphite grade P 0.5-0.6 Cross-linking agent NITs-PU-5 22.0-24.5.

1 bp

Description

The inventive utility model relates to the field of engineering, namely the production of bushings having a low coefficient of friction, and can be used in the suspension of the brake shoe for all types of rail transport: in passenger and freight railway trains, trams, subway trains.

Known bushing suspension shoe for rail vehicles (see RF patent No. 2298707 for the invention of "Bush lever brake system of rail vehicles", IPC: F16C 13/04, B61H 13/34, claimed 04.10.2005). The specified sleeve is made of two-layer polymer composite materials, the inner layer of which is a working slip layer and contains a fibrous filler, a binder and a release agent, and phenol-formaldehyde or cresol-formaldehyde resin in the form of novolac and / or rezol form is used as a binder. The known sleeve design according to the patent of the Russian Federation No. 2298707 for the invention is insufficiently reliable in operation due to the possible separation of its layers and, in addition, emits harmful phenol, formaldehyde and dust into the environment during production.

This is the disadvantage of the known invention according to the patent of the Russian Federation No. 2298707 for the invention.

The sleeve according to the patent 2298707 for the invention is selected as the closest analogue (prototype), because by its technical nature and the achieved effect it is closer to the claimed utility model.

The objective of the claimed utility model is to increase reliability during operation and increase the environmental safety of production.

The technical result consists in reducing the maximum friction temperature, which increases the ease of sliding, helping to reduce the wear of the bushings and providing an increase in the service life, as well as to improve the production conditions of the bushings by reducing harmful emissions.

This task is achieved in that the suspension sleeve of the brake shoe for rail vehicles made of a composite material containing a fibrous filler, a binder and a release agent, according to a utility model, the sleeve is made of a composite material containing, as a fibrous filler, a urethane prepolymer of the SIC-PU-5 grade , as a release agent - graphite powder grade P, as a binder - a cross-linking agent brand NIC-PU-5, in the following ratio of components, wt.%:

Urethane prepolymer NITs-PU-5 75.0-77.5 Powder graphite grade P 0.5-0.6 Cross-linking agent NITs-PU-5 22.0-24.5.

Studies on patent and scientific and technical sources of information indicate that the proposed utility model is unknown and does not follow explicitly from the studied prior art, and, therefore, meets the criterion of "novelty."

The inventive utility model can be manufactured in specialized workshops of a machine-building enterprise by vacuum molding without pressure using standard domestic or imported equipment, well-known technologies and materials commercially available from the industry. Vacuum manufacturing does not produce air pores, which can cause rupture, penetration of the sleeve wall during braking.

A worn bush can be replaced at the place of use without contacting the appropriate repair shops.

The ability to manufacture and use the proposed utility model ensures that it meets the criterion of "industrial applicability".

The proposed set of essential features informs the claimed device of new properties that allow to solve the problem.

When choosing the material for the manufacture of the sleeve from fibrous polymer composite materials, it was taken into account that they “represent complex systems consisting of reinforcing fibers and a polymer matrix (or binder). The strength of such materials depends on a number of physico-chemical and technological factors, often closely related to each other. The key role in ensuring the strength of fibrous composites is played by the adhesive strength of the fiber-matrix compound, (see Yu.G. Bogdanova. Adhesion and its role in ensuring the strength of polymer composites. Lomonosov Moscow State University. - M., 2010, website nano.msu.ru). The “fiber-matrix” materials were experimentally selected from a number of polymer composite materials, as a result of which the urethane prepolymer grade NITs-PU-5 TU 2253-179-07507802-2002 and the cross-linking agent NITs-PU-5 TU 2413-178-07507802 were chosen -2002 The selected cross-linking agent, NITs-PU-5 brand, is a solution of 3,3-dichloro-4,4-diaminophenylenemethane (40%) in polyester (60%) - polytetramethylene ether glycol (polyfurite) (see http: // www. vedco.ru/gtg_rf/gtd.php?id=30182636 and http://www.sibtender.ru/postav/product.asp?id=1444714&id=241000&sort=2). Preference was given to domestic brands, among which there are worthy, superior in some characteristics to foreign analogues. Attention was drawn to their physical and technical characteristics, for example, Shore A hardness, tensile strength, operating temperature range, and others. They are given in the article “Properties of polyurethanes of various grades” (see the website http://www.upkomplekt.ru/articles/1/). The suspension shoe of the brake shoe for rail vehicles, designed to absorb the suspension when it is fixed, works in conditions of intense abrasive wear and high shock pressures. Reducing the influence of these indicators on the reliability of the sleeve is possible by ensuring ease of sliding of the sleeve on the metal surfaces with which it is in contact. It was necessary to choose a release agent that reduces the upper limit of temperatures that arise when the sleeve is rubbed against metal. They became powder graphite grade P.

The material of the sleeve in the following ratio of components, wt.%:

Urethane prepolymer NITs-PU-5 75.0-77.5 Powder graphite grade P 0.5-0.6 Cross-linking agent NITs-PU-5 22.0-24.5

It was experimentally installed and provided the necessary indicators of anti-wear and antifriction properties of rubbing parts, which increased the reliability of the bushings during operation.

In turn, this set of essential features ensured the achievement of a technical result: a decrease in the maximum friction temperature and an increase in sliding ease, contributing to a reduction in wear of the bushings and providing increased reliability during operation, as well as an improvement in the production conditions of the bushings due to the reduction of harmful emissions.

The proposed utility model is illustrated in the drawing, which shows a General view of the sleeve in the context of the Assembly with the bracket of the side frame, roller and suspension of the brake shoe.

The sleeve 1, inside which the roller 2 is installed, is provided with a chamfer 3 on one end and a flange 4 on the other end, the outer surface of which is pressed against the bracket 5 for attaching the side frame (to hell, not shown) of the car. The chamfer on the protrusion 3 facilitates the installation of the sleeve 1 in the eye 6 of the suspension of the brake shoe, and the flange 4 does not allow the sleeve 1 to fall out of the eye 6. The roller 2, the bracket 5 and the eye 6 are made of metal. The figure of the drawing shows the safety washer 7 and the sleeve 8 phenol-plastic, to the end of which the flange 4 is pressed.

The friction surfaces creating a friction pair are the inner surface of the sleeve 1 and the outer surface of the roller 2, the outer surface of the flange 4 with the end face of the sleeve 8 phenol-plastic and the bracket 5 for attaching the side frame of the car, as well as the outer surface of the sleeve 1 in contact with the eye 6.

Were made three samples of the sleeves shown in Table 1, with different percentages of components, wt.%.

Table 1 Component 1st sample 2nd sample 3rd sample Urethane prepolymer NITs-PU-5 78 76 71 Powder graphite grade P 0.3 0.5 0.8 Cross-linking agent NITs-PU-5 21.7 23.5 28,2

In the first sample, the content of the NIC-PU-5 urethane prepolymer is selected above the stated limit, the content of the remaining components is below the limit. In the second sample, the content of all components is within the limit. In the third sample, the content of the NIC-PU-5 urethane prepolymer is selected below the stated limit, the content of two other components is selected above the declared limit. At a lower percentage of the urethane prepolymer NITs-PU-5, the sample has a higher hardness and at minus temperatures becomes brittle, which contributes to rapid wear. In addition, the sleeve will not bend and there will be difficulties when installing it in the suspension eye. With a higher percentage of the NIC-PU-5 urethane prepolymer, the sample has lower hardness and wears out faster. With a lower percentage of graphite of powder grade P, the friction force increases and the temperature is higher, which leads to rapid wear. With a higher percentage of graphite of powder grade P, graphite settles on the surfaces of the brake shoe suspension roller, which causes increased wear of the sleeve. With a normal percentage of cross-linking agent NITS-PU-5, the sleeve is of medium softness and evenly wears out, that is, it serves reliably, since the physical properties of the material of the sleeve do not change, and with a higher percentage of cross-linking agent NIC-PU-5, the sleeve is more hard and at subzero temperatures more fragile, subject to faster wear. A sleeve subject to rapid wear is unreliable.

The above samples were tested under conditions as close as possible to real conditions. The bushings were installed in the suspension eye, and a roller was installed in them. The tests lasted 2 hours, the speed of rotation of the roller was 3000 rpm. The test results are summarized in Table 2.

table 2 1st 2nd 3rd SIC Characteristic sample sample sample PU-5

Shore A hardness, conv. units 80-84 90-91 95-98 88-95 Tensile strength, MPa, not less 19.7 19.6 19.9 19.6 Elongation at break,%, not less than 370 355 350 350 Top temperature mode, no more than + 100 ° C 89 80 75 + 100 ° C

The performance characteristics of the samples were compared with the characteristics of the SIC-PU-5 polyurethane, since its characteristics are close to the characteristics of the prototype material.

In sample 1, Shore A hardness is low, the tensile strength and elongation are exceeded, the temperature regime does not exceed the norm. The sleeve is soft, had increased wear.

In sample 2, almost all indicators are within normal limits, including temperature conditions. The sleeve is elastic, elastic. Depreciation is invisible.

In sample 3, Shore A hardness reached an upper limit, the tensile strength exceeded the upper limit, elongation is normal and the temperature regime is not higher than + 100 ° C. The sleeve is solid. Depreciation is invisible. There were difficulties in installing the sleeve in the eye of the suspension because of its hardness.

An example of a sleeve.

All components of the composite material in accordance with their qualitative and quantitative ratio are mixed in a vacuum machine until a homogeneous mass is obtained for 5 minutes at a speed of rotation of the petals of the machine at least 1500 rpm at a temperature of + 24 ° C. Then the composite material is poured into split molds and placed in an electric kiln at a temperature of + 80 ° C. Heating in the furnace continues for four hours until external curing is achieved, after which the molds are transferred to an electric furnace with a temperature of + 40 ° C, where they are kept for 20 hours until fully cured. For one sleeve weighing 35 g, a prepolymer of urethane grade NITs-PU-5 26.25-27.125 g, graphite of powder grade P 1.75-2.1 g, and a cross-linking agent NITs-PU-5 7.7-8.575 are consumed.

The advantages of the claimed utility model:

- reliability in operation;

- improving the environmental safety of production;

- reduction of sleeve wear;

- increase in service life.

Claims (1)

Brake shoe suspension bush for rail vehicles made of a composite material containing a fibrous filler, a binder and a release agent, characterized in that the bush is made of a composite material containing a urethane prepolymer of the NIC-PU-5 grade as a fibrous filler, and graphite as a release agent powder grade P, as a binder - a cross-linking agent brand NITs-PU-5, in the following ratio of components, wt.%: Urethane prepolymer NITs-PU-5 75.0 - 77.5 Powder graphite grade Π 0.5 - 0.6 Cross-linking agent NITs-PU-5 22.0 - 24.5

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