EA039869B1 - Brake pad of a railway vehicle - Google Patents

Abstract

The invention relates to railway transport, namely brake pads of railway vehicles. The technical result of the invention is to increase service life of a brake pad by reducing the unevenness in wear of its friction element. The technical result obtained is a brake pad that includes a composite friction element, whose rear part is reinforced with a backplate made of perforated steel tape and a wireframe; its feature is that the wireframe is made of two identical rectangular frames, on one short side of each of which there is a junction of the ends of the wire the frame is made of, while the end of the wire of each frame is bent by the radii along the long side of the frame and across the frame away from the back side of the pad; and the frames are connected into the wireframe with formation of an eye in the area of their connection to make a hole in this eye for the pin fastening the pad to the brake shoe, while the short sides of the frames are connected by a bridge located on the line of joints of the wire ends of each frame. The frames are connected by a bridge at the junction of the frames, and at the same time, they are interconnected by electric welding at the adjoining areas of the frames and the areas where the wire ends of the frames and the faces of the bridge adjoin the frames. The frame is curved along the radius with the center located on the symmetry axis of the frame, which is less than the radius of the rear side of the brake pad by the value of the frame location in the mass of the composite friction element.

Description

The claimed invention relates to railway transport, namely to the brake pads of railway vehicles.

A brake shoe of a railway vehicle is known, including a composite friction element and a metal frame made of interconnected wire frames (RU 186770 U1, 07/30/2018). The frame has a wide frame, a narrow frame, a closed loop, and an open loop. The connection of the ends of the wire of the bent contour of the frames by welding is located on the arc of the rear part of the friction element and is made by applying one wire to the other, while the thickness of the frame along this arc is doubled. This greatly limits the maximum allowable wear and pad life before replacement.

The maximum allowable wear implies a guaranteed absence of the possibility of the wire frame touching the railway wheel, which is possible in the event of wear of the composite friction element and the appearance of ring scratches or welds on the wheel tread surface.

The disadvantage of the design according to patent RU 186770 U1 is also the presence of a wide and narrow frames of the frame, as this leads to uneven reinforcement of the composite friction element and different strengths of the left and right parts of the brake shoe.

Known brake shoe, in which the presence of closed and open parts of the frame and the ratio of their areas P1/P2=0.04-18 does not eliminate the uneven reinforcement around the perimeter of the back side of the composite friction element (RU 2397092 C1, 15.06.2009).

Also known are the designs of composite friction brake pads, in which there are closed and open parts of the frame frames (RU 185601 U1, 08/13/2018. RU 185423 U1, 08/13/2018. RU 2414369 C1, 12/15/2009). In these pads, the ends of the wires welded by welding according to the schemes disclosed in the patents lead to an increase in the thickness of the frame arcs and uneven reinforcement of the composite friction element, which is a disadvantage of pads having different frame widths.

The closest analogue of the invention presented in this description is a brake shoe of a railway vehicle, including a composite friction element, the back of which is reinforced with a perforated steel tape butt plate and a wire frame (RU 2386561 C2, 03/19/2008 - prototype).

The perforated steel tape and the frame are pressed into an array of a composite friction element, while the wire frame is made of two interconnected frames. The joining of the ends of the wire by welding is performed on the arc of the frame from the back side of the shoe without overlapping the wires on each other, the wires are located longitudinally to each other. With such a joining of the frame wires, the frame thickness does not increase significantly, as is the case in the block design according to patent RU 186770 U1, while the arc thickness increases due to the strengthening of the weld and deformation of the wires during welding.

The disadvantage of the prototype is the presence of a wide and narrow frames of the frame, which do not provide uniform reinforcement of the left and right parts of the composite friction element, the uniformity of the strength of the pad along its length and width and, as a result, the uneven wear of the friction element, which negatively affects the service life of the pad. This is due to the fact that with the selected optimal distance of the frame wires from the side surface of the composite friction element for one of the frames, this distance cannot be maintained for the second frame, since it has a different width when the frame is symmetrically located relative to the side surfaces of the composite friction element.

The technical result of the invention presented in this description is to increase the service life of the brake pad by reducing the unevenness of its friction element and the minimum size of the worn pad.

The technical result is obtained by a brake shoe of a railway vehicle, including a composite friction element, the rear part of which is reinforced with a perforated steel tape butt plate and a wire frame, characterized in that the frame is made of two identical rectangular frames, on one short side of each of which there is a joint of the ends of the wire , from which the frame is made, while the end of the wire of each frame is bent along the radii along the long side of the frame and across the frame away from the back side of the block, the frames are connected into a frame with the formation of an eye in the area of their connection to locate a hole in this eye for the checks for attaching the block to the brake shoe, while the short sides of the frames are connected by a jumper located on the line of joints of the ends of the wire of each frame.

The frames are connected by a jumper located at the junction of the frames, and at the same time, at the junction of the frames, the ends of the wires of the frames and the ends of the jumper to the frames, they are interconnected by electric welding.

The frame is curved along the radius with the center located on the axis of symmetry of the frame, which is less than the radius of the rear side of the brake shoe by the value of the location of the frame in the array of the composite friction element.

In FIG. 1 is a general view of a composite friction brake shoe.

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In FIG. 2 - wire frame of the brake shoe.

In FIG. 3 - view A in Fig. 2.

Positions in the drawings indicate:

- composite friction element of the brake shoe;

- perforated butt plate reinforcing the rear surface of the composite friction element;

- wire frame, reinforcing composite friction element;

- the working surface of the brake pad, in contact with the outer surface of the wheel during braking (with the tread surface);

- rear surface of the brake pad;

- the central boss of the brake shoe;

- side lugs of the brake pad;

- an eyelet for skipping checks;

- connected rectangular frames of the wire frame;

- jumper connecting the upper parts of the frames;

- the short sides of the frames on which the wire joints are located;

- the long sides of the frames, along which the short sides of the frames are bent along the radius r;

- the contour of the side surface of the brake pad.

The brake shoe (Fig. 1) includes a composite friction element 1, the back of which is reinforced with a back plate 2 made of perforated steel tape and a wire frame 3 (Fig. 3) having two identical rectangular frames 9 made of strong steel wire. The end parts of the wire of each frame are bent in the longitudinal and transverse planes of the block so that the ends of the wire of each frame converge at the junction a and this forms a short side 11 of each frame 9 (Fig. 2, 3). Joint a is located on the short side 11 of each frame 9.

The short side 11 of each frame 9 is bent along the long side 12 of the frame and across to it away from the rear surface 5 of the block along the radii r (Fig. 2). Frames 9 are interconnected in one wire frame. The bent parts of the frames form an eye 8 (Fig. 1) for passing checks (not shown) through it, while the short sides 11 of the frames 9 are connected by a jumper 10 (Fig. 3). The ends of the jumper are located at the junction a symmetrically with respect to the junction line. All the mentioned frame and frame elements are connected by electric welding.

The radius R of the frame (Fig. 2), the center of which lies on the axis of symmetry of the frame, is less than the radius of the back surface of the composite friction element 5 by the amount of immersion of the frame into the composite friction element 1 from the back side of the block.

In the construction of the shoe, two interchangeable frames 9 of the same size are used, and in connection with this, the equipment for manufacturing the carcass of the shoe is simplified.

Frames 9 are manufactured on unified equipment, they have the same residual elastic deformations, which are more accurately fixed and controlled during the manufacture of frame 3. As a result, the complexity of manufacturing the frame of the block is reduced and the accuracy of its dimensions is increased. Since the carcass (Fig. 3) has the same width H along the entire length L of the brake shoe, this allows it to be positioned at an equal distance B from the side surface of the brake shoe when forming the shoe. As a result, uniformity of reinforcement was achieved along the entire longitudinal section of the pad, uniformity of pad strength along the length and width, and more uniform wear of the friction element of the brake pad.

The connection by welding of the ends of the wire of the bent contour of the frames 9 was transferred from the arcs of radius R of the frames 9 (Fig. 2) to their upper part, which made it possible to obtain the minimum thickness d (Fig. 2) along the arc R without thickening. Each joint a of the ends of the wire of the frame is adjacent to the end of the jumper 10, the ends of which are welded to the ends of the wire of the two frames at the junction a, which made it possible to increase the rigidity of the frame 3 and increase the strength of the welded joint of the joints a.

The brake pad works as follows. The brake shoe is installed in the brake shoe (not shown) so that it rests on the shoe with its back surface 5 (Fig. 1), the central boss 6 enters the transverse groove of the shoe, and the side bosses 7 (Fig. 1) are located in the longitudinal grooves shoe (slots not shown). Then the check is inserted into the eyelet 8 in the central boss 6 and into two holes of the shoe.

When braking the car wheel, the brake shoe is pressed by the working surface 4 to the outer surface of the wheel rolling. In this case, the boss 6 keeps the block from moving relative to the shoe tangentially to the circumference of the wheel and from falling out of the shoe, which is prevented by a check fixed in the holes of the shoe and in the lug 8 of the boss 6. During the operation of the shoe, the side bosses 7 (Fig. 1) included in the longitudinal grooves of the shoe keep the block from displacement across the wheel and the block works in the plane of rotation of the wheel.

The wheel is braked from a pneumatic cylinder through a system of levers (not shown) by pressing the working surface 4 of the shoe against the outer rolling surface of the railway wheel, while due to sliding friction the wheel is braked.

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In the process of pressing the brake pad to the wheel, compression forces arise on the friction element 1 and the frame 9 of the pad frame. At the same time, the frames evenly redistribute these forces along the length and width of the brake shoe, as a result, the wear of the friction element of the shoe occurs more evenly over the entire working surface of the brake shoe in contact with the outer rolling surface of the car wheel.

By increasing the uniformity of the reinforcement of the composite friction element, its strength and wear uniformity were increased, the permissible thickness of the worn part of the brake shoe was reduced, which made it possible to ensure more uniform wear of the friction element and increase the service life of the brake shoe.

The described technology for the production of brake pads is acceptable for the actual production conditions of existing enterprises.

CLAIM

Claims (3)

1. Brake shoe of a railway vehicle, including a composite friction element, the rear part of which is reinforced with a perforated steel tape butt plate and a wire frame, characterized in that the frame is made of two identical rectangular frames, on one short side of each of which there is a joint of the ends of the wire, from which the frame is made, while the end of the wire of each frame is bent along the radii along the long side of the frame and across the frame away from the back side of the block, the frames are connected into a frame with the formation of an eyelet in the area of their connection to locate a hole in this eyelet for pins attaching the block to brake shoe, while the short sides of the frames are connected by a jumper located on the line of joints of the ends of the wire of each frame. 2. The brake shoe according to claim 1, characterized in that the frames are connected by a jumper located at the junction of the frames, and at the same time, at the junction of the frames, the ends of the wires of the frames and the ends of the jumper to the frames, they are interconnected by electric welding. 3. The brake shoe according to claim 1, characterized in that the carcass is curved along the radius with the center located on the symmetry axis of the carcass, which is less than the radius of the rear side of the brake shoe by the size of the carcass in the array of the composite friction element.