RU2381934C1 - Car bimetal braking clamp - Google Patents

Abstract

FIELD: railway transport. ^ SUBSTANCE: bimetal braking clamp comprises arc-bent cast pig-iron bar furnished with a boss arranged at rear side center and having a bore to receive wedge-like cotter-pin to be fixed in clamp holder. Said cast pig-iron bar body has cylindrical inserts arranged in rows and made from material that features higher abrasive properties compared with those of bar material. Groups of inserts are separated by sections with no inserts, said inserts being point-welded to steel plate repeating the shape of and covering bar rear side. Steel plate is perforated to have 25 mm-dia holes in compliance with arrangement of inserts in bar body. Two inserts should be located opposite each round hole. Insert face overlaps round hole area for 1/3. Insert face is eclectically welded to round hole edge. In casting, mould is filled so that steel plate round holes are filled with pig-iron. Square holes are arranged along steel plate edges to receive pig-iron U-section bosses. Length of section with no inserts exceeds both width. ^ EFFECT: uniform wear of braking surfaces, wheels locking in all braking conditions. ^ 8 dwg

Description

The invention relates to railway transport and relates to brake equipment, namely brake pads of railway rolling stock. Bimetal carriage brake shoe (hereinafter referred to as shoe) is designed for railway rolling stock of both foreign and domestic production.

To date, several types of blocks of various designs made of various materials are used on passenger, freight cars and other rolling stock.

The claimed block is designed to replace existing composite and cast iron pads, is another development of a family of bimetallic brake pads for rolling stock of railway transport.

Known bimetallic brake pad according to copyright certificate No. 1643266, Mcl. B61H 1/00 Bull. No. 15, April 23, 91. The block contains an arcuate casting in the form of a bar of rectangular cross section, while at least two parallel rows of inserts are made in the body of the bar from the side of the working friction surface, the axis of the rows of which are parallel to the side of the block, are fixed in the body cylindrical inserts made of a material having a higher abrasiveness than the material of the beam. The inserts are staggered.

A disadvantage of the known brake pad is the rapid wear due to the seizure of the seizure on the entire surface of the pad, which entails wear of the pad itself, a decrease in the effect itself at high speeds of 80 ÷ 90 km / h due to overheating of the inserts, as well as premature failure when there are cracks of cast iron between the inserts.

The most structurally close is a bimetallic brake shoe containing an arc-shaped casting in the form of a curved cast-iron bar, with a tide, under a wedge-shaped check. The casting is made by casting iron into a mold in the body of which cylindrical inserts are made in longitudinal rows made of a material of higher abrasiveness than the material of the beam. The inserts are placed in two groups, in each group the inserts are located in two parallel rows, the groups of inserts are separated by a section without inserts. The inserts are spot welded to the steel frame. The steel frame is made in the form of a plate with sections repeating the shape of an arcuate-curved beam. The steel frame has a profile section, covering a tide of cast iron beam, with holes in the side surface for fixing the block with a wedge pin in the shoe (block holder). Parallel rows of inserts are deployed at an angle α = 15 ÷ 20 ° in one direction in both groups. The inserts are made of heat-resistant steel.

The inserts are fixed to the frame plate by spot welding. The four extreme inserts in the rows are made with annular grooves on the side surface.

The working surface of the block is made with a slope of 1:20. Patent RU 2298500, M. cl. B61H 1/00, F16D 65/04, F16D 69/00, publ. 05/10/2007, Bull. No. 13.

However, this design of the pads has disadvantages that adversely affect the performance of the pads and a fairly high cost in production. As practice has shown, in blocks with their wear by 80 ÷ 85%, micromotion of cast iron occurs on the annular grooves of the inserts, as a result of which the thermal conductivity of the block as a whole decreases and the friction coefficient decreases, increasing the length of the braking distance.

In addition, due to the inaccuracy of the placement of the inserts on the frame and in the body of the pads on the surface of the wheels, there are developments in the form of annular grooves.

In addition, the difficulty of automating the manufacture and assembly of the frame with inserts will not make it possible to reduce the cost of pads in production.

As practice has shown, with wear of 90% of the thickness of the block, there is a slight weakening of the connection of a cast-iron curved beam with a steel frame and inserts fixed to the frame, and the fixing of the inserts by spot welding to the frame is not strong enough.

The objective of the invention is to increase the life of the pads and the wheels associated with them, the reliability of the brakes, ease of manufacture by increasing the strength of fixing the inserts on the steel frame by welding and due to the features of cast iron casting technology for the manufacture of beams with a more accurate location of the inserts in the body of the cast iron block.

This object is achieved in that the bimetallic carriage brake shoe contains an arcuate curved cast-iron bar having a tide on the rear side, a tide with an opening for a wedge-shaped pin for mounting in a shoe holder, made by casting iron into a mold. In the body of the beam, cylindrical inserts made of a material of higher abrasiveness than the material of the beam are placed in longitudinal rows. The inserts are placed in two groups and are separated by a section without inserts. The inserts are electrowelded to a steel plate covering and repeating the shape of the rear side of the timber.

The steel plate is made of perforated round holes with a diameter of 25 mm in accordance with the layout of the inserts in the beam so that two inserts are located opposite each hole. In this case, the ends of the inserts 1/3 overlap the area of the round hole. The ends of the inserts are welded electrically to the edge of the hole. When casting iron, the mold is filled so that these holes in the steel plate are filled with cast iron. At the ends of the steel plate, rectangular holes are made for cast-iron tides having a channel shape in cross section. The length of the plot without inserts K exceeds the width of the tide C and is determined by the formula

K = (1.75 ÷ 1.85) C,

where K is the length of the block without inserts;

C is the width of the tide.

The novelty of the invention lies in its design features.

- The steel plate is made of perforated round holes with a diameter of 25 mm in accordance with the layout of the inserts in the body of the beam in such a way as to place two inserts opposite each hole. The inserts are arranged so that their ends 1/3 overlap the area of the round hole. The inserts are electrically welded to the edge of the hole. The layout of the round holes on the steel plate in accordance with the specified parameters for the uniform placement of the working surface of the inserts on the working surface of the block is calculated on a computer and accurately transferred to the steel plate when it is perforated. In accordance with the calculated grid of coordinates, an electric welding arc apparatus is also configured, which, under the flux layer, welds the inserts to the steel plate, which simplifies manufacturing and eliminates manual labor.

- When casting iron, the mold is filled so that these holes in the steel plate are filled with cast iron. In this case, powerful T-hooks are formed by cast iron for the ends of the inserts, which increases the strength and durability of the pads.

- At the ends of the steel plate, rectangular holes are made for cast iron tides having a channel shape in cross section. In the recess of the channel, the ends of the wedge check are placed when it is installed, which allows you to more accurately fix the position of the check and prevent the block from turning relative to its longitudinal axis. This improves the working conditions of the pads and ensures uniform wear of the working surface.

- The length of the section without inserts K exceeds the width of the tide C. This allows you to increase the strength of the pads in the mounting area in the shoe.

The set of essential features of the invention allows to 90% automate the pads production process and achieve accurate placement of inserts in the body of a cast iron bar, which improves the quality of the resulting pads, improves its operational properties. The strength of the pads increases due to changes in the technology of its manufacture, the cost of production decreases.

The resulting design allows you to achieve uniform wear pads and the surface of the wheels. This eliminates the occurrence of annular grooves on the surface of the wheels of the wheels during operation and blocking of the wheels in all braking modes in any weather and any time of the year, ensures that there are no burns, fatty and sliders on the surface of the wheels, this block creates a wheel-saving braking mode when braking.

The inserts are made of a more abrasive metal or alloy, including heat-resistant steels, the hardness of which does not exceed 155 units. HB.

When calculating the geometry of the location of the inserts in the body of a cast iron bar on a computer, a number of parameters are set.

The length of the plot without inserts K exceeds the width of the tide C and is determined by the formula

K = (1.75 ÷ 1.85) C,

where K is the length of the block without inserts;

C is the width of the tide.

Each of the two groups of cylindrical inserts contains 8-10 inserts, each of the rows in the group contains 4-5 inserts.

The working surface of the brake pads is made according to the profile of the surface of the wheel with a slope of 1:20 or another slope in accordance with the standards of other countries of the world.

The area S of the working surface of the pads is determined by the formula

S = (3.21 ÷ 5.46) × S ₂ + S ₁ ,

where S is the area of the working surface of the pads;

S ₂ - the sum of the areas of the working surfaces of the inserts;

S ₁ - the area of the plot without inserts.

The area of the plot without inserts is determined by the formula

S ₁ = K × B,

where S ₁ is the area of the plot without inserts;

K is the length of the block without inserts;

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

The diameter d of the cylindrical inserts is determined by the formula

d = (3.0 ÷ 4.0) × V,

where d is the diameter of the cylindrical insert;

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

The length of the cylindrical insert is determined by the formula

L = (0.95 ÷ 0.96) × H,

where L is the length of the cylindrical inserts;

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

Abrasiveness of a block block is determined by the formula

C = (0.6 ÷ 0.7) × M,

where C is the abrasiveness of the timber pads;

M is the abrasiveness of the insert.

All cylindrical inserts are placed in a conductor according to a geometrical computer-designed circuit, opposite the round holes of the perforated steel plate in pairs and are welded to the steel plate by an electric welding machine under the flux from the back of the steel plate. A package of inserts together with a steel plate is placed in a casting mold and molten in cast iron so that the round holes are filled with cast iron, and powerful T-hooks are formed by cast iron at the ends of the inserts. From the working surface of the block, all inserts are filled with a 3 ÷ 4 mm layer of cast iron, i.e. closed, except for four extreme installation in the mold.

The design features of the pads allow to automate its production by 90%, improve its performance and reduce the cost of production.

Steel inserts and T-shaped cast iron bays in the perforations of the steel plate provide better heat dissipation and therefore, as practice has shown, the block does not lose friction coefficient during braking at high speeds of 90-140 km / h.

High mechanical properties, superior to the properties of bimetallic and cast iron blocks of early production, allow you to operate it to wear, amounting to 0.12 of the original thickness.

In general, the block, having good thermal conductivity and heat capacity, provides elastic-plastic friction at a block temperature of up to 750 °, increasing the service life of the blocks and the surface of the wheels.

In the brake shoe, its rear mounting part is made in the form of a steel plate with sections repeating the shape of an arcuate curved beam and located in the middle of the profile section in the form of a tide with holes in the side surface for fixing the shoe with a wedge pin or other method in accordance with the standards of any country in the world .

In the steel perforated plate at the ends are made rectangular holes for cast iron tides having a channel shape in cross section. When installing the block and securing it with a check, the ends of the checks are located inside the channel, which prevents the block from turning relative to its longitudinal axis.

On the steel perforated plate are placed and secured through openings on the back side by an electric submerged-arc welding machine, steel inserts arranged in a geometric pattern designed for computers. After such an arrangement, a steel perforated plate with steel inserts welded to it is laid in a mold and filled with molten cast iron, the chemical composition of which is shown in the table, or cast iron of a different chemical composition.

Table
Cast iron composition. Group FROM Si Mn P S C ₁ 2.8-3.4 0.7-1.1 0.4-1.1 0.4-0.9 no more than 0.2 F 2.8-3.5 1.3-2.0 0.3-0.9 1.0-1.5 no more than 0,15

Cast iron melt fills the mold, including holes in the steel plate, through which the inserts are welded, forming powerful T-shaped spikes in this connection, one spike for two inserts. These spikes, together with the rush from the back of the block in the middle of the curved beam and inserts, provide a good connection of the cast iron of the beam with the steel plate of the back side of the block and a powerful heat removal from the working surface of the wheel, saving it from sharp thermal effects with corresponding negative consequences - the development of microcracks.

The block operating mode with timely and high-quality heat removal from the place of working contact of the block-wheel friction pair provides more reliable braking with a large coefficient of friction and, together with the prevention of microcracks on the working surface of the wheels, as well as the complete absence of wheel lock on any braking modes, are wheel-saving that do not allow damage to the surface of the wheels: sliders, Navar, burns, thermal cracks, dents, etc.

The working part of the block is made with a slope of 1:20 or another in accordance with the standards of other countries of the world, which allows to increase the working surface of the inserts, since it takes the form of an ellipse when the block is working, which helps to increase the resource of the block.

The inserts are made of ductile metal or alloy with a hardness of not more than 155 units. HB and their fastening to a steel perforated plate by electric welding, as practice has shown, provide reliable fastening of the inserts and good heat dissipation from the working surface of the block.

Calculation of the length of the cylindrical insert depending on the thickness of the block makes it possible to create blocks for casting them with cast iron to a height of 3–4 mm from the working side, which makes it possible to wear this layer of cast iron and run in the body of the block together with the inserts on the surface during the first braking wheel rolling, providing a high-quality braking effect from the first braking cycles, given that practically due to various wear and a different number of wheel bores due to damage to all wheels and they have different radii of the riding surface and require individual running-in of the blocks of each to its wheel. The issue of quick running-in of pads and the initial quality of braking in this case is solved due to the fact that all inserts are closed with a 3 ÷ 4 mm layer of cast iron.

The inserts have a higher abrasiveness than the body of the pad.

The installation and overall dimensions of the pads, as well as the tide from the back for mounting in the shoe with a wedge pin or in another way, can be performed according to the standards of any country in the world.

The resource of the declared unified bimetallic brake pads exceeds the resources of existing bimetallic brake pads by 5–8%, and cast iron by ten times. According to environmental standards, the block significantly surpasses any composite pads both in production and in operation and is completely harmless.

According to its mechanical characteristics, the claimed block significantly exceeds the prototype and other bimetallic blocks due to the reliable connection of the cast iron bar of the body of the block with steel inserts and a steel plate due to the cast iron inlet in the holes.

The invention is illustrated by the drawings shown in Fig.1-8.

Figure 1 shows a General view of the pads with a section going through a series of inserts. A layer of cast iron covering the ends of the inserts from the side of the working surface is conventionally not shown.

Figure 2 shows a General view of the pads.

Figure 3 is a sectional view of a block along AA.

Figure 4 - placement of inserts opposite the hole of the plate.

Figure 5 is a view of a steel perforated steel plate from the side of the working surface of the block.

6 is a view of a steel perforated plate from the back of the block.

7 is a cylindrical insert.

On Fig - wedge check.

The bimetallic car brake shoe contains an arcuate curved cast-iron bar 1 and a steel perforated plate 2 with round holes 3 with a diameter of 25 mm. The holes 3 are placed in accordance with the layout of the inserts in the body of the beam 1. When casting iron into holes 3, T-shaped bays of cast iron 4 are obtained. The steel plate 2 has an opening 5 for a wedge-shaped check. At the ends of the steel plate 2, rectangular holes 6 are made for cast-iron tides having a channel shape in cross section 7. Cylindrical inserts 8 are placed in longitudinal rows in the body of the cast-iron beam 1.

The beam 1 has a transverse tide 9 located in the middle with an opening 5 for a wedge pin 10 for mounting in a block holder.

The ends of the two inserts 8 1/3 overlap the area of the round hole 3, the ends of the inserts are welded by electric welding to the edge of the hole 3.

Inserts 8 are placed in two groups and are separated by a section without inserts.

The length of the plot without inserts K exceeds the width of the tide C and is determined by the formula.

On the steel perforated plate 2, the following holes of Figure 2 are made:

- from 8 to 10 holes 3 for welding the inserts 8 to the plate 2 with the formation of a T-shaped bay 4 of cast iron in this hole 3,

- holes 5 for the wedge pin 10,

- holes 6 for trailer cast-iron tides 7 supports of wedge-shaped checks 10 or another method of fastening, made to the standards of any country in the world.

In Fig.3, in the body of the cast-iron beam 1 there are cylindrical inserts 8 made of various metals or their alloys and welded by an electric welding machine to the edges of the technological holes 3 in the frame 2 of at least two inserts 8 in one hole. Cast iron poured into this hole when pouring the frame forms a mushroom-shaped (in cross-section T-shaped) casting 4, which reliably connects the body of the block 1 to the frame 2.

In figure 4, the insert 8 is fixed by an electric welding machine to the frame 2 through the technological holes 3 in a geometric pattern designed for computers. According to the same scheme, an electric welding machine is configured. The number of inserts for the entire block is 16 ÷ 20 pieces, depending on the speed characteristics of the block, its length and width, diameter and material of the inserts.

The brake shoe is made by casting iron in a mold with a pre-laid steel perforated plate 2, on which the inserts are fixed by electric welding 8. The entire package is filled with molten iron, forming a curved beam 1 with a tide 9 from the back in the middle or a tide of a different configuration in accordance with the standard of any country for fixing the pads in the shoe holder through the holes 5 with a wedge pin 10, a finger or other fastening.

The insert 8 is made of metal with an abrasiveness higher than the abrasiveness of the body of the cast-iron beam 1.

The work of the unified brake pad is ensured by pressing the pad against the wheel's surface, in this case, the interaction of the friction pair of the block - wheel occurs, in this case there is elastoplastic friction with a friction coefficient of 0.48 ÷ 0.50, the conditions for this friction to occur:

1. the body of the pads - cast iron of groups C ₁ , F and other cast irons, hardness 197 ÷ 255 units N.V.

2. soft inserts from various metals and their alloys, hardness not more than 155 units N.V.

3. wheel rolling surface, hardness 235 ÷ 340 units HB.

4. the maximum heat resistance of the pads is not lower than 750 ° C.

The production of the proposed block implies a higher coefficient of automation of production, therefore, lower cost. The proposed technical solution of the device and the manufacture of the pads allows you to get a better and with a longer service life block. When using it, the wheels do not lock, and consequently, the damage associated with this phenomenon. In addition, the structural strength of the block itself due to the more mechanically strong connection of the perforated steel plate with the cast-iron curved bar of the block and inserts ensures its high reliability and operation without damage in all modes of braking of the rolling stock.

Claims (1)

The bimetallic carriage brake shoe contains an arcuate curved cast-iron bar having a tide located on the rear side transverse to the middle with a hole for a wedge-shaped pin for mounting in a shoe holder, made by casting iron into a mold in the body of which cylindrical inserts made of higher abrasive material are placed in longitudinal rows, than the material of the beam, the inserts are placed in two groups and are separated by a section without inserts, the inserts are attached by spot welding to a steel plate, covering and repeating the shape of the back side of the beam, characterized in that the steel plate is made of perforated round holes with a diameter of 25 mm in accordance with the layout of the inserts in the body of the beam so that opposite each round hole there are two inserts, with the ends of the inserts at 1 / 3 cover the area of the round hole, the ends of the inserts are welded by welding to the edge of the round hole, when casting iron, the mold is filled so that these round holes in the steel plate are filled by ugong, at the ends of the steel plate, rectangular holes are made for cast iron tides having a channel shape in cross section, the length of the section without inserts K exceeds the width of tide C and is determined by the formula
K = (1.75 ÷ 1.85) C,
where K is the length of the block without inserts;
C is the width of the tide.

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