RU62188U1 - RAILWAY BRAKE PAD - Google Patents

Abstract

The invention relates to shoe braking devices, namely, brake pads of railway vehicles. The brake shoe contains a composite friction element, a metal frame made of steel strip, a solid insert welded to the metal frame located in the central part of the shoe and a wire frame. The brake shoe is equipped with a central boss with a pin hole and side bosses made of composite friction material. The wire frame is a block pressed into the friction material of the back side of the shoe, along the perimeter of the shoe, two closed frames, the inner parts of which are mutually overlapped and bent outward of the back of the shoe, forming an eyelet for passing checks. The metal frame of the steel strip is made less than the width of the wire frame, bent along the radius of the back surface of the block and pressed into the back surface of the block between the side bosses and under the central boss. The composite friction element is made of two longitudinal layers of material, and the layer located on the back side of the shoe has a strength greater than the layer located on the back side of the shoe has a strength greater than the layer located on the working side of the shoe due to the higher content of reinforcing fibers and / or larger. The solid insert can be made of cast iron.

Description

The inventive utility model relates to brake devices, namely, to brake pads of railway vehicles.

Known cast iron brake pads, including those with a metal frame, manufactured according to GOST 1205-73 "Cast-iron brake pads for railroad cars and tenders. Design and main dimensions. ”

These pads have a positive effect on the rolling surface of the wheel, however, they have a low coefficient of friction and during operation provide low braking efficiency, and therefore, require high tension of the lever gear during braking, do not provide silent and smooth braking of the train, have a lot of weight (16 kg), high wear and high cost.

The known technical solution is used for the same purpose as the claimed one and has a common essential attribute “brake shoe” with it.

Known brake composite pad containing a composite friction element and a metal (steel) frame. (B.A.Shiryaev "Production of brake pads from composite materials for railway cars", Moscow, Chemistry, 1982 (p. 9-13, 70) .

The metal steel frame consists of one part - the main strip, and sometimes two parts: the main strip and welded to it on the inside of the reinforcement plate. The main strip of the frame has an external curved contour around the perimeter of the finished block, and in the center is a U-shaped or semicircular protrusion forming a central boss. The central boss of the frame is equipped with holes for the pin (metal bracket). On the main plate of the frame are also located

two side bosses serving as guides for checks. The central boss serves for fastening the brake pads in the brake shoe by means of checks, and the guides (side bosses) simplify the mounting of checks.

The reinforcing plate is used to give additional rigidity to the frame and increase the reliability of mounting the frame with a friction element.

The reinforcing plate is provided with holes for welding to the main strip, as well as for flowing the friction mixture during molding in order to increase the fastening with the friction element.

Holes and / or half-holes can also be cut out on the main strip with bending of the non-cut out part of the holes inside the block to obtain spikes for flowing into the holes of the friction mass during molding and to improve the fastening with the friction element.

Compared to cast iron pads, brake pads have received much wider use, since they have a higher friction coefficient, lower pressing force and wear resistance, several times longer service life, lower weight, cost, and also provide silent and smooth braking of the train.

However, during the operation of the brake composite pads, individual defects may occur, including: thermal cracks on the surface of the wheels, wear of the surface of the wheels, decrease in the brake efficiency of pads when water enters the friction zone (rain, snow), as well as in the presence of coal or peat dust and leaves on the surface of the rail.

In addition, with this design, pads with strong vibrations and frosts, the friction element is torn off from the metal frame, and sometimes the metal frame is destroyed in the place of the U-shaped protrusion.

Salient features of the brake pad “friction element”, metal frame, central boss equipped with a pin hole and side bosses ”- guides for checks are common with essential features of the claimed utility model.

Known block railway vehicle copyright certificate of the USSR No. 518403 (IPC 61 N 7/02, 1976), consisting of friction material and a metal frame. The metal frame is a back plate made in the form of two closed frames pressed into the friction material around the perimeter of the block, the internal parts of which are mutually overlapped and bent outward of the back of the block, forming an eyelet for skipping checks. The back plate is equipped with a metal mesh or perforated plate pressed into the friction material. This frame received the name of wire mesh in serial production, as it consists of wire and mesh frames.

The main significant external and structural difference between composite blocks with a wire mesh frame and composite blocks with a steel metal frame is that the central boss of these blocks is made of composite material with internal reinforcement, which sharply increases the elastic-elastic properties of the block and, as a result, the vibration resistance of the block and eliminates the separation of the composite material from the frame (see B.A. Shiryaev. Production of brake pads from composite materials for iron railway cars. M. Chemistry 1982, pp. 9-14). These pads, in comparison with composite pads with an all-metal frame, also have a longer service life, lower cost and metal consumption. However, they also have the disadvantages indicated above inherent to composite blocks in comparison with cast-iron blocks.

The known technical solution is used for the same purpose as the claimed one and has common essential features with it: “composite friction material” and “wire frame, made in the form of the back of the block pressed into the friction material, around the block perimeter, two closed frames, inner parts which are mutually overlapped and bent outward of the back of the block, forming an eyelet for skipping checks "," Central boss with a hole for a check and two side bosses are also made of friction composite Therians ".

In recent years, compositional brake pads with solid cast iron inserts have been tested in railway vehicles, which can improve the performance of composite brake pads during rain and icing, increase heat transfer to the environment, and it is better to clean the wheel of various substances that may rail, as well as reduce thermal cracks, sliders, bows formed on the wheel and fill small cracks with cast iron when it is melted at high temperatures cheers.

These pads are called wheel-saving, as they can dramatically increase the resource of the wheel.

Known brake pad, mainly a railway vehicle according to the patent of the Russian Federation No. 2188347 from 08.27.2002. The brake pad contains a metal wire frame and a friction part consisting of three inserts fixed to it. The central insert is made of cast iron and equipped with a pin hole, and the other two inserts are made of composite friction material and are located on both edges of the solid insert.

This brake pad allows you to increase the braking efficiency and increase the resource of the wheels, however, it has insufficient strength and service life. The thermal conductivity of cast iron is several times greater

thermal conductivity of the composite material, and the heat resistance of the composite material is insufficient. At the joints of the cast iron insert with composite inserts, on the surface of their contact during operation, the composite material gradually burns out, as a result of which the brake shoe loses its required stiffness and can be divided into three parts, connected only by a wire frame, during long-term operation.

The known technical solution is used for the same purpose as the claimed one and has common essential features with it: “metal wire frame”, “friction part fixed to it”, “solid insert”, “friction composite material”.

The closest analogue is the brake shoe of a railway vehicle according to the patent of the Russian Federation No. 52957 of 04/27/2006.

The considered brake shoe contains an all-metal frame made of a steel strip with a U-shaped protrusion in its central part, forming a central boss with a pin hole, a composite friction element and a solid cast iron insert.

A solid insert is located in the center of the block and is welded to the metal frame from the inside on both sides of the U-shaped protrusion.

The composite friction material is first molded into a steel metal frame and a cast-iron insert in the mold under pressure, and then vulcanized to them in the mold under pressure at temperature.

The durability and service life of this block is greater than that of the above.

However, considered by the closest analogue brake pad also has disadvantages.

With this design of the pads, providing a rigid structure of the frame as a whole, the required strength of the frame in its U-shaped protrusion, which is obtained by bending a flat steel strip in the stamp, is not provided.

During stamping of the steel frame, microcracks are formed in the bending places, which, with constant vibrations and loads on the protrusion during operation, increase and the frame breaks, and then, under increased loads, the weld also breaks and one half of the block breaks away from the other half. In addition, due to vibrations and variable loads during severe frosts, the friction composite element sometimes breaks away from the metal frame and the cast-iron insert, especially after the surface of the composite friction material at the point of contact with the high-conductivity cast iron insert is burned due to its insufficient heat resistance and low thermal conductivity.

The known technical solution is used according to the same attribute as the claimed one and has essential features in common with it: "metal frame made of steel strip", "friction composite element", "solid insert located in the center of the block and welded to the metal frame" .

The task to which the claimed brake shoe is directed is to increase the strength of the shoe.

The tasks are solved by the brake pad of a railway vehicle, containing:

- composite friction element, consisting of two longitudinal layers, and the layer located on the back side of the block has a strength greater than the layer located on the working side of the block;

- a central boss with a pin hole and two side bosses made of a more durable composite material;

- wire frame, which is pressed into the composite friction material of the back of the block, along the perimeter of the block, two closed frames, the inner parts of which are mutually overlapped and bent outward of the back of the block forming an eyelet for passing checks;

- a metal frame made of steel strip, made less than the width of the wire frame, curved along the radius of the back surface of the block and pressed into the back surface of the block between the side bosses and under the central boss;

- a solid insert located in the center of the brake pad and welded to the metal frame.

Composite friction element is made of two longitudinal layers of two different composite friction materials, characterized by different strengths.

Composite friction material of the working layer located on the side of the working surface of the block is made of a polymer composition containing usually a polymeric binder (rubber, resin or combination), a vulcanizing group, various fillers and additives, as well as reinforcing fibers (usually mineral, artificial, synthetic, metal fibers or shavings). The composition of the composite friction material, the non-working layer located on the back side of the block, should have increased strength compared to the working layer in order to eliminate chips from the back of the block and expose or tear the wire frame from the back of the block. The increase in the strength of the composite friction material is ensured by increasing the content in it

the composition of the reinforcing fibers and / or changes in their range and size. In some cases, this is also achieved by an additional increase in the content of the binder to reduce the stiffness of the block and give it more flexibility, that is, the ability to elastic-elastic deformation without fracture and, as a result, resistance to vibration and mechanical stress.

An increase in the binder content in the composition of the material simultaneously leads to an increase in the adhesion and fastening of the composite material with a metal frame.

In order to increase the heat resistance of the material, heat-resistant reinforcing fibers, for example metallic, are used in its composition.

The composition of the working and non-working layers is determined in accordance with the purpose and operating conditions of the pads.

The wire frame is currently manufactured in series by cutting pieces of wire with a diameter of 4 mm, bending and welding closed and curved frames from them, then inserting them into each other and welding together at the center of the resulting frame at the point of contact, so that the inner parts they are mutually overlapped and bent outward forming an eyelet for skipping checks in the central boss after the frame is formed inside the back of the block.

The metal frame of a steel strip, for example, 2-4 mm thick, is made by stamping with a width less than the width of the wire frame and is bent along a radius equal to the radius of the back of the block.

In order to fix the position of the solid insert in relation to the metal frame and improve its fastening in the metal frame and block, including and by molding to the composite material, it is provided with an opening in its central part for mounting the upper part of the solid insert into this opening. To fix the metal frame in the mold and with respect to the wire frame on both sides of the metal frame next to the above hole through

Four antennae can bend the jumper. This is also done to reduce the area of the steel strip of the metal frame passing under the central boss in order to improve the fastening of the central boss with the body of the block. The holes formed from the cutting of the mustache contribute to the flow of excess composite material from the body of the block to the central boss and vice versa during molding.

To improve the fastening of the composite element with a metal frame, holes and half-holes with spikes (teeth) can be made in the frame.

A solid insert can be made of cast iron by casting, and its upper part equal to or close to the thickness of the metal frame, for example, 4 mm thick, is made in dimensions slightly smaller, for example, 2 mm on each side of the corresponding hole in the metal frame. The solid insert is then inserted into this hole and welded to the metal frame along the width or length of the insert on both sides.

In order to provide a cleansing, polishing and therapeutic (pouring cast iron material of small microcracks of the wheel) impact on the wheel over the entire contact surface of the block with the wheel, the cross section of the block with the insert has a shape that does not differ from the shape of the block in its other cross sections with a composite friction element. In order to avoid breakage of the molds, the insert dimension in cross section can be provided 1-3 mm less than that of the composite friction element.

Figure 1 presents the brake pad of a railway vehicle, where

1 - composite friction element, consisting of two longitudinal layers;

2 - a metal frame from a steel strip;

3 - solid insert;

4 - wire frame;

5 - central boss with a hole for the pin;

6 - side bosses.

Figure 2 presents a General view of the solid insert assembly with a metal frame made of steel strip and wire frame brake pads of a railway vehicle.

The technology for manufacturing brake pads includes the following steps:

- manufacturing (casting) of cast iron insert;

- the manufacture of a metal frame from a steel strip by stamping;

- installation of a solid insert in a metal frame and its welding to the frame;

- manufacturing and welding of wire frame from wire;

- manufacture of composite friction materials for the working and non-working layers;

- laying in the mold of a wire frame, a metal frame with a solid insert, a hinge of the inoperative layer and the working layer of composite friction materials, followed by molding under pressure in the press;

- vulcanization of blocks in the mold under pressure and at temperature;

- drilling holes on the check in the brake shoe.

In exceptional cases, when using rusty or contaminated metal reinforcement or when special requirements for the strength of the block are met, the reinforcement can be cleaned of rust, degreasing and glueing using conventional known technologies to improve adhesion and fastening of the metal reinforcement with the composite friction element.

When performing the pads in the manner described in the characterizing part of the utility model formula, the solid insert is rigidly connected by a welding method to a metal frame which is pressed into the rear surface of the brake pad between the side bosses and under the central boss. The central boss with a pin hole and side bosses are made of durable composite friction material. The entire back side of the block, with a depth equal to the thickness of the pressed frame, is also made of durable composite friction material. A wire frame is pressed into the back of the brake pad and the body of the central boss. The manufacture of a composite friction element from two longitudinal layers makes it possible to better fulfill various requirements for these layers.

The excess heat generated on the working layer in the place of contact of the brake pads with the wheel is removed through a solid insert and a metal frame to the non-working (back) side.

The implementation of the inventive brake pads with the characteristics indicated in the characterizing part of the formula allows to increase the strength of the pads, the reliability of operation and the life of, for example, a composite brake pads with a solid insert of cast iron.

The sturdy, reliable design of a composite brake pad with a solid insert, for example made of cast iron, in turn, will achieve stable braking performance, including during icing and rain, increase heat transfer to the environment, provide a cleaning and polishing effect on the wheel, and fill the smallest cracks on the wheel with cast iron during its melting at high temperatures and to increase the service life of the wheel.

Claims (1)

A brake pad of a railway vehicle containing a composite friction element, a metal frame made of steel strip and a solid insert welded to it located in the central part of the block, characterized in that the block contains a wire frame, which is pressed into the friction material of the back side of the block, the perimeter of the pads, two closed frames, the inner parts of which are mutually overlapped and bent outward of the back of the pads, forming an eyelet for skipping checks, a central boss with a hole for a check, and two side bosses made of composite friction material, the metal frame of a steel strip made less than the width of the wire frame, bent along the radius of the back surface of the block and pressed into the back surface of the block between the side bosses and under the central boss, and the composite friction element is made of two longitudinal layers of material, and the layer located on the back of the block has a strength greater than the layer, located on the working side of the pads.