RU2308392C2 - Lipless bimetallic brake shoe for locomotive - Google Patents

Abstract

FIELD: railway transport; brakes of rolling stock.

SUBSTANCE: proposed brake shoe contains cast iron bar on rear side of which boss is arranged containing steel member for wedge-like cotter of shoe holder made in form of shaped section of steel plate enclosing the boss. Hole to pass wedge-like cotter is made in boss. Member is secured on steel plate covering bra from rear side and passing under boss. Found at edges of bar over ends of steel plate are T-shaped cast iron projections for engagement with brake shoe holder. Inserts made of material, abrasiveness differing from abrasiveness of cast iron bar are fitted in body of cast iron bar. Inserts are cylindrical, being arranged on steel plate with embedding into cast iron bar in two groups. Centers of three nearest inserts in each group are equidistant from each other. Groups of inserts are separated by section without inserts, and four extreme cylindrical inserts in groups are provided with ring grooves on side surface. Each group consists of seven insets.

EFFECT: increased balanced service life, reliability, efficiency increased service life of wheels owing to reduction of their wear caused by brake bimetallic shoes.

12 cl, 5 dwg

Description

The invention relates to railway transport and relates to braking equipment of traction rolling stock with a track of 1520 mm ..

A brake shoe is known that contains an arc-shaped casting in the form of a bar of rectangular cross section, consisting of the main and profile sections, while at least two parallel rows of cylindrical steel inserts are made in the bar body from the side of the working rubbing surface. The inserts are staggered. Four profile inserts are placed in the profile section, interacting together with the body of the block with the crest of the bandage of the locomotive’s wheelset. Patent No. 2153994, M. cl. B61H 1/00, F16D 65/04, 69/00, Bull. No. 22, 08/10/2000

A disadvantage of the known brake pad is the moderate wear of the crest of the brace from the impact of the profile area of the shoe, as well as the increased weight of the shoe due to the presence of the profile area.

Known brake of a railway vehicle containing a friction pair consisting of a wheel and a brake pad. Solid inserts are fixed in the body of the block, located symmetrically relative to the transverse axis of the block at a distance from each other equal to at least half the length of the block. Patent No. 1572889, M. cl. B61H 1/00, Bull. No. 23, 1990, p. 95.

The inserts are made of special cast iron with high hardness, which causes intense wear on the surface of the wheels.

The implementation of the prismatic inserts with a continuous friction surface affects heat dissipation and contributes to even greater wear of friction pairs and a decrease in braking force due to a decrease in the friction coefficient.

The closest is the design of the brake pads with solid inserts for locomotives. Krylov V.I., Perov A.N., Ozolin A.K., Klimov N.I. Handbook of brakes. - Ed. 3rd, rev. and add. M .: Transport, 1975, p. 377, fig. 237. The block can be ridge and ridgeless. It consists of an arcuate curved cast-iron beam, in the body of which from the working side in longitudinal rows there are inserts of material with an abrasiveness different from the abrasiveness of cast-iron beam. On the back of the beam there is a metal steel narrow plate located in the center of the beam and passing under the tide. On the back side there is a cast-iron tide containing a steel element under the wedge-shaped pin of the block holder. The steel element is made in the form of a bracket, the legs of which are welded to a steel metal plate. On the back side of the timber above the ends of the steel plate, T-shaped protrusions are made for interfacing with the brake shoe.

In this device, the inserts are made of cast iron having high hardness HB-400, which causes intense wear on the surface of the wheels.

The inserts are located only in the lower part of the cast iron bar of the block and are not connected to a steel metal plate, which impairs heat dissipation.

The installation of a wedge-shaped check in a steel bracket, which is fixed by welding on a steel plate and cast from the sides with cast iron, does not have sufficient reliability.

The objective of the invention is to create a new design of a bimetallic brake pads for a locomotive having an increased balanced resource, reliability, efficiency, which also allows to increase the resource of the wheels of the rolling stock by reducing wear on their brake bimetallic pads and the complete absence of the impact of the pads on the brace ridge. The new design allows to improve the manufacturing technology of pads while improving their quality.

The task is achieved by the fact that it is proposed block of a new design without a profile area and with reduced weight.

A ridge-free bimetallic brake shoe for a locomotive contains cast iron cast into the shape of an arcuate curved cast-iron bar, on the back of which there is a tide containing a steel element under the wedge-shaped check of the shoe holder. The steel element is made in the form of a profile section of a steel plate covering the tide. In the tide there is a hole for a wedge-shaped check, and on the side surfaces of the profile section at the level of the hole there are windows for fixing the block with a wedge check in the block holder, the element is mounted on a steel plate covering the beam from the back and passing under the tide. Along the edges of the timber over the ends of the steel plate are made T-shaped protrusions of cast iron for interfacing with the brake shoe. In the body of the cast iron bar, inserts of a material with an abrasiveness different from the abrasiveness of cast iron bar are placed. The inserts have a cylindrical shape and are placed on a steel plate with immersion in a cast iron bar. The inserts are placed in two groups, in each of which the centers of the three nearest inserts are equidistant from each other. Groups are divided by a plot without inserts. Four extreme cylindrical inserts in groups are made with annular grooves on the side surface, and each group consists of seven inserts.

The inserts are made of heat-resistant steel.

The rows of inserts are deployed relative to the longitudinal axis of the body of the block in one direction at an angle α = 10-11 °.

The area of the plot P without inserts between groups of inserts is determined by the formula

P = (0.14 ÷ 0.16) × S,

where P is the area of the plot without inserts;

S is the full working surface of the pads.

The working surface of the brake pads and inserts on the side of the working surface are made with a slope of 1:20.

The area T of the working surface of the pads without inserts is calculated by the formula

T = (5.6 ÷ 7.2) × t,

where T is the surface area;

t is the sum of the working surfaces of the inserts.

The diameter d of the cylindrical insert is found by the formula

d = (0.18 ÷ 0.30) × V,

where d is the diameter of the cylindrical insert;

In - the width of the working surface of the pads.

The distance C between the centers of the cylindrical inserts in the group is found by the formula

C = (0.10 ÷ 0.12) × L,

where C is the distance between the centers of the cylindrical inserts in the group;

L is the length of the block.

The length of the cylindrical insert A is found by the formula

A = (0.91 ÷ 0.93) × H,

where A is the length of the cylindrical insert;

H is the thickness of the block without the thickness of the steel plate.

All cylindrical inserts from the side of the working surface of the block when casting a cast iron bar are poured with a 2-3 mm layer of cast iron.

The abrasiveness of the material of the inserts exceeds the abrasiveness of the material of the body of the pad.

Steel inserts are mounted on a steel frame plate by spot welding.

The novelty of the proposed design of a combless bimetallic block for a locomotive is as follows.

- The inserts are made of heat-resistant steel with an abrasiveness different from the abrasiveness of cast iron timber.

- The inserts have a cylindrical shape and are placed on a steel plate with immersion in a cast iron bar.

- The inserts are placed in two groups, in each of which the centers of the three nearest inserts are equidistant from each other, the group of inserts is separated by a section without inserts. Each group consists of seven inserts.

- Formulas are given for determining: the area of the plot without inserts P, the area of the working surface of the block without inserts T, the diameter of the cylindrical insert d, the distance between the centers of the cylindrical inserts in group C, the length of insert A.

- The working surface of the brake pads and inserts on the side of the working surface are made with a slope of 1:20.

- Four extreme cylindrical inserts in groups are made with annular grooves on the side surface.

The design of the proposed ridgeless bimetallic pad for a locomotive can improve the reliability and efficiency of the brake pad by increasing its wear resistance and friction coefficient.

The technical result is achieved due to the following essential features of the invention.

Steel inserts in conjunction with steel tape on the back of the block provide reliable heat dissipation and cooling of the working part of the block.

The design of the pads and the material of the inserts from which they are made provide the occurrence of elastoplastic friction. High mechanical properties, superior to bimetallic and solid cast iron blocks, allow you to operate it at the final stage of wear before replacing it with a thickness of up to 0.16 of its original size. Provides elastic friction and the preservation of the coefficient of thorns at the temperature of the pads at 1100 ° C, increases the service life of the pads.

In the proposed design, there is no profile section of the block that interacts with the crest of the wheel bandage, which prevents its wear, this also reduces the weight of the block.

The claimed block is a further development of the well-known family of bimetallic blocks. In the brake shoe, its rear part (non-working, installation) is made in the form of a steel plate with sections repeating the shape of an arcuate curved beam, and located between them in the middle of the profile section, covering the cast-iron tide. Thus, the tide is additionally covered from the sides and from the top with a steel profile, which can significantly increase the strength of this node. On the side surfaces of the profile section there are windows located opposite the hole in the tide to fix the shoe with a wedge-shaped check of the shoe holder.

On the plate are placed and fixed by spot welding of a cylindrical shape of the insert with installation in groups, with seven inserts in each group. In each group, the centers of the three nearest inserts are equidistant from each other. This allows you to accurately place the insert in the body of the pads, avoiding their displacement when casting iron, and significantly reduces the marriage in the manufacture and improves the quality of the pads.

After such a completion of the plate with cylindrical inserts and their rigid fastening on it by contact spot welding, in essence, the finished back of the block is placed in a mold and filled with molten iron. As a result, we get a cast-iron casting on a steel plate with soft steel inserts made of heat-resistant steel placed inside it. Cast iron is also poured under the profile section of the steel plate. Pads are marked in accordance with the resource, which is regulated by the number and diameter of the inserts.

Making inserts from a bar on guillotine shears and forming them into a package directly on the steel frame of the pad by spot welding allows you to automate the entire manufacturing process of the pad, including casting the workpiece with molten cast iron, and freeing the pad from the mold (mold), which generally drastically reduces the cost pads.

Placement of inserts in groups, arrangement of rows of inserts with a slope offset by 10-11 ° relative to the longitudinal axis of the block, the presence of a section of area P without inserts provides an effective braking mode by improving heat transfer to the back side through steel inserts in conjunction with a steel plate of the back of the block and cooling of the working part of the block, which eliminates overheating of the block, which means it ensures that at high braking speeds and when the brakes work on prolonged long slopes, the blocks do not overheat I don’t “flow”, i.e. Do not lose the coefficient of friction.

The ranges of the ratio of sizes entered in the claims, as significant distinguishing features were established experimentally as a result of bench tests.

The shift of the rows of inserts due to their deviation from the longitudinal axis of the block by α = 10-11 °, the selected distance between the centers of the inserts in the row allows overlapping along the width of the rubbing surface of the block with inserts, prevents the formation of a longitudinal crack along the row both in the manufacturing process and in during operation, ensures minimal wear of the block and the uniformity of abrasion over the entire height of the block over its entire surface, which affects the increase in the life of the block, and also reduces wheel wear taking into account high speeds braking.

Compliance with the ratio of the area of the rubbing working surface of the block without inserts T, depending on the sum of the working surfaces of the inserts t and the diameter of the cylindrical insert d on the width of the working surface of the block B, provides effective braking in a different range of speeds of the rolling stock.

The slope of the working surface of the pads and inserts provides a better fit without a gap and interaction with the wheel surface of all the inserts simultaneously on the full working surface, creating elastic-plastic friction, which increases the resource of the proposed pad and significantly reduces wear on the surface of the wheel, eliminating wear of the tire ridge.

All inserts are made of plastic metal of a cylindrical shape, and some of them (extreme inserts) for more reliable fastening of cast iron on a steel frame have one annular groove on the side surface, which, as practice has shown, ensures high reliability of the connection of the bimetallic structure of the block as a whole and extends its service life. The inserts are grooved toward the steel plate.

Calculation of the length of the cylindrical insert, depending on the thickness of the block, allows for the manufacture of the block to create the opportunity for casting them with cast iron to a height of 2-3 mm. This allows for the first braking to ensure abrasion of this layer, and there is a complete running-in of the entire working surface of the block to the surface of the wheel, including the insert. It also creates better conditions for the work of a pair of skating surfaces of the wheel and block and increases their service life.

As practice has shown, the resource of a bimetallic block is 30-75 times greater than the resource of any cast-iron block.

A ridgeless bimetallic brake pad for a locomotive is shown in FIG. 1, FIG. 2, FIG. 3, FIG. 4, FIG. 5.

In Fig.1 shows a General view of the pads, Fig.2 is a section of the pads along the plane aa, Fig.3 is a cylindrical insert, Fig.4 is a cylindrical insert with an annular groove on the side surface, Fig.5 shows a view of B .

The ridge-free bimetallic brake shoe for a locomotive is made in the form of a steel plate 1 adjacent to an arcuate curved cast-iron beam 2 of length L, width B, thickness H, in the body of which cylindrical inserts 3 of diameter d, length A are made of heat-resistant steel. The plate 1 has a profile section 4. The insert 3 is welded to the plate 1, and the whole package is cast iron, forming an arcuate curved beam 2 (Figure 1). In the lateral surfaces of the profile section 4, windows 5 are made, located opposite the hole in the tide 6 under the wedge-shaped check of the block holder. On the steel plate 1, inserts 3 are arranged in parallel rows, in two groups. The number of inserts in group 7, the centers of the nearest inserts are equidistant from each other by a distance C. Inserts 3 are attached to the steel plate 1 by contact welding. The rows of inserts 3 are deployed relative to the longitudinal axis of the block at an angle of 10 ÷ 11 ° in one direction. The working surface of the cast iron beam 2 and inserts 3 has a slope of 1:20 (Figs. 1-4). On the back side of the cast-iron beam 2, T-shaped protrusions 7 are made for interfacing with the brake shoe (Figs. 1, 5). The area of the working surface of the block T, t is the sum of the working surfaces of the inserts.

Figure 2 shows a section of the block along the plane AA, where 1 is a steel plate with a profile section 4 with a tide and a window 5 for fixing the block with a wedge check in the block holder. The dashed lines show the inserts 3 welded to the steel plate.

Figure 3 shows a cylindrical insert 3.

Figure 4 shows the extreme steel cylindrical insert 3 having an annular groove on the side surface.

Figure 5 shows the placement of the T-shaped protrusion 7.

The working rubbing surface of the block consists of the surface of cast iron and the surfaces of the inserts.

The inserts 3 are made of ductile metal, heat-resistant steel, having a higher abrasiveness M than the material of the body of the block - cast iron S. Preferred excess abrasiveness of the material of the inserts is not less than 2 times. Our proposed placement of inserts 3 in the body of the block ensures continuous contact of the block with the locomotive wheel over the entire width of the bandage without breaks, except for the working surface of the ridge, preventing its wear and "undercutting" by the block.

The work of the brake pad is performed by pressing the working surface of the pad to the bandage of the locomotive wheel, the resulting interaction provides elastic-plastic friction with a coefficient K> 0.42. Elastoplastic friction conditions:

a) the body of the pads is cast iron, the hardness is 197-241 units. HB;

b) soft inserts - steel, hardness 120-140 units HB;

c) the surface of the wheel brace - steel, hardness 195-210 units HB;

g) the maximum heat resistance of the pads while maintaining the specified coefficient of friction of not less than 1100 ° C.

The combination of the cast iron body of the pad and soft inserts during interaction and friction with the wheel surface provides not only elastoplastic friction, but also prevents the “use” of locomotive wheel pairs on rails, which, in turn, ensures the absence of “sliders” on the wheel surface and in the absence of ridge wear, increases the bandage resource of the locomotive’s wheelsets as a whole.

Compared with the prototype in the proposed design there is no profile section, the weight of the pads is reduced, however, this ensures the reliability of the brakes due to the high abrasiveness of the inserts and a high coefficient of friction.

Thanks to the proposed technical solution, the reliability and efficiency of the brakes of locomotives is increased with an increase, as practice has shown, by a dozen times the resource of pads and significantly less wear of the bandages of wheel sets, with the complete absence of wear of the crests of the band from the effects of the pads.

Claims (12)

1. A ridge-free bimetallic brake shoe for a locomotive, containing cast iron in the form of an arcuate curved cast-iron beam, on the back of which there is a tide containing a steel element under the wedge-shaped check of the block holder, the steel element is made in the form of a profile section of a steel plate covering the tide, in the tide there is a hole for a wedge-shaped check, and on the side surfaces of the profile section at the level of the hole there are windows for fixing the block with a wedge check in the block encoder holder, the element is mounted on a steel plate covering the beam from the back and passing under the tide, T-shaped protrusions made of cast iron for mating with the brake shoe are made along the edges of the bar above the ends of the steel plate, characterized in that the body of the cast-iron bar contains material inserts with an abrasiveness different from the abrasiveness of cast iron timber, while the inserts are cylindrical in shape and placed on a steel plate immersed in a cast iron beam, the inserts are placed in two groups, in each of which the centers of the three nearest of the inserts are equidistant from each other, the group of inserts is separated by a section without inserts, while the four extreme cylindrical inserts in the groups are made with annular grooves on the side surface, and each group consists of seven inserts. 2. A ridgeless bimetallic brake pad for a locomotive according to claim 1, characterized in that the inserts are made of heat-resistant steel. 3. A ridgeless bimetallic brake shoe for a locomotive according to claim 1, characterized in that the rows of inserts are deployed relative to the longitudinal axis of the body of the shoe in one direction at an angle α = 10-11 °. 4. A ridgeless bimetallic brake pad for a locomotive according to claim 1, characterized in that the area of the plot P without inserts between groups of inserts is determined by the formula: P = (0.14 ÷ 0.16) · S, where P is the area of the plot without inserts; S is the full working surface of the pads. 5. A ridgeless bimetallic brake pad for a locomotive according to claim 1, characterized in that the working surface of the brake pad and insert on the side of the working surface are made with a slope of 1:20. 6. A ridgeless bimetallic brake pad for a locomotive according to claim 1, characterized in that the area T of the working surface of the pad without inserts is calculated by the formula: T = (5.6 ÷ 7.2) where T is the surface area; t is the sum of the working surfaces of the inserts. 7. A ridgeless bimetallic brake shoe for a locomotive according to claim 1, characterized in that d the diameter of the cylindrical insert is found by the formula: d = (0.18 ÷ 0.30) · V, where d is the diameter of the cylindrical insert; In - the width of the working surface of the pads. 8. A ridgeless bimetallic brake shoe for a locomotive according to claim 1, characterized in that the distance C between the centers of the cylindrical inserts in the group is found by the formula: C = (0.10 ÷ 0.12) · L, where C is the distance between the centers of the cylindrical inserts in the group; L is the length of the block. 9. The ridgeless bimetallic brake pad for a locomotive according to claim 1, characterized in that the length of the cylindrical insert A is found by the formula: A = (0.91 ÷ 0.93) · N, where A is the length of the cylindrical insert; H is the thickness of the block without the thickness of the steel plate. 10. A ridge-free bimetallic brake shoe for a locomotive according to claim 1, characterized in that all cylindrical inserts from the side of the working surface of the shoe when casting a cast iron bar are poured with a 2 ÷ 3 mm layer of cast iron. 11. A ridgeless bimetallic brake pad for a locomotive according to claim 1, characterized in that the abrasiveness of the material of the inserts exceeds the abrasiveness of the material of the body of the pad. 12. A ridgeless bimetallic brake pad for a locomotive according to claim 1, characterized in that the steel inserts are mounted on a steel frame plate by spot welding.

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