Metal-ceramic brake lining for high-speed electric train

Abstract

The utility model relates to railway transport, namely to metal-ceramic brake linings, which are an integral part of the brake unit of a high-speed electric train disc brake.The technical result provided by the utility model is an increase in the efficiency of lubrication between the sliding contact radius surface of the balancer on the rear side and the corresponding surface of the radius seat of the supporting frame, the surface of the spherical frame of the friction segment and the surface of the radius cup of the balancer during operation of the lining, due to the use of a material covering the balancers, performing the function of lubrication between the contacting surfaces, having increased antifriction properties, simultaneously exhibiting high load-bearing capacity, forming a film that operates effectively under conditions of extremely high dynamic loads, and, at the same time, ensuring a reduction in the coefficient of friction and stabilization of its value regardless of the humidity of the working environment, without subjecting the friction surfaces to increased wear during sliding under conditions of high contact loads at extremely high temperatures.A metal-ceramic brake lining for a high-speed electric train includes a supporting frame and friction segments mounted on the supporting frame by means of balance beams; the spherical frame of the friction segment is mounted in a corresponding radius cup of the balance beam with the ability to slide relative to each other, and the balance beams, having a radius surface on the back side, are mounted in corresponding radius seats of the supporting frame with the ability to slide relative to each other; the surface of the balance beams has an antifriction heat-resistant coating that performs the function of lubrication between the radius surface of the balance beam on the back side and the corresponding surface of the radius seat of the supporting frame, the surface of the spherical frame of the friction segment and the surface of the radius cup of the balance beam, which are in contact during sliding, wherein the antifriction heat-resistant coating is made in the form of molybdenum disulfide. 11 ill.

Description

[0001] The field of technology to which the utility model belongs.

[0002] The utility model relates to railway transport, namely to metal-ceramic brake linings, which are an integral part of the brake unit of a disc brake of a high-speed electric train.

[0003] Technique level.

[0004] The prior art includes a technical solution for utility model patent CN203202076 (U), SHANDONG GOLD PHOENIX CO LTD, F16D65 / 04, F16D69 / 04, publ. 18.09.2013, which is the closest to the claimed utility model, which presents a description of a train brake lining, which includes a mounting plate and a friction block installed on the mounting plate with the help of a regulator, the friction block is divided into a first friction block and a second friction block, each first friction block and two second friction blocks are installed in a triangular arrangement with the help of a regulator, the mounting plate and the regulator are provided with a plurality of grooves for ball cups, the mounting ball cup of the regulator is installed in the groove for the ball cup of the mounting plate, the ball of the friction block is installed in the groove for the ball cup of the regulator, and the positioning pin of the friction block is secured to the mounting plate with a spring; the regulator is uniformly coated with graphite.

[0005] The general features that coincide with the essential features of the claimed utility model are: a train brake lining that includes a supporting frame (mounting plate) and friction segments (blocks) mounted on the supporting frame with the help of balancers (regulators), the spherical frame of the friction segment (friction block ball) is mounted in the corresponding radius cup (slot for the ball cup) of the balancer (regulator) with the ability to slide relative to each other; the balancers, having a radius surface on the back side (ball cups), are mounted in the corresponding radius sockets (grooves) of the supporting frame with the ability to slide relative to each other; the balancers are uniformly covered with an antifriction material.

[0006] The technical problem that could not be solved in the implementation and use of the above-described analogue of the utility model is that the design of the above-described analogue does not sufficiently ensure the effectiveness of lubrication between the sliding contact radius surface of the balancer on the back side and the corresponding surface of the radius seat of the supporting frame, the surface of the spherical frame of the friction segment and the surface of the radius cup of the balancer, since the material used as an antifriction heat-resistant coating that performs the function of lubrication - graphite, due to its insufficiently high adhesive properties to metal, forms a film that is not capable of operating effectively under high loads, sinceAs the load increases, the coefficient of friction of graphite increases, reducing resistance to movement and decreasing its load-bearing capacity, which prevents graphite from effectively performing its lubricating function, subjecting friction surfaces to increased wear due to the increased friction force under high contact loads. In addition, the effectiveness of the lubricating action of graphite is highly dependent on the humidity of the working environment; its effectiveness is greater in a humid environment, while the working environment in which the lining operates can be different, both wet and dry.

[0007] Disclosure of the essence of the utility model.

[0008] The technical result provided by the utility model is an increase in the efficiency of lubrication between the sliding contact radius surface of the balancer on the rear side and the corresponding surface of the radius seat of the supporting frame, the surface of the spherical frame of the friction segment and the surface of the radius cup of the balancer during the operation of the lining, due to the use of a material covering the balancers, performing the function of lubrication between the contacting surfaces, having increased antifriction properties, simultaneously exhibiting high load-bearing capacity, forming a film that effectively operates under conditions of extremely high dynamic loads, and, at the same time, ensuring a reduction in the coefficient of friction and stabilization of its value regardless of the humidity of the working environment, without subjecting the friction surfaces to increased wear under conditions of high contact loads at extremely high temperatures.

[0009] The technical result is achieved by producing a metal-ceramic brake lining for a high-speed electric train, which includes a supporting frame and friction segments mounted on the supporting frame by means of balance beams; the spherical frame of the friction segment is mounted in a corresponding radius cup of the balance beam with the ability to slide relative to each other, and the balance beams, having a radius surface on the back side, are mounted in corresponding radius sockets of the supporting frame with the ability to slide relative to each other;the surface of the balancers has an anti-friction heat-resistant coating that performs the function of lubrication between the sliding contact radius surface of the balancer on the rear side and the corresponding surface of the radius socket of the supporting frame, the surface of the spherical frame of the friction segment and the surface of the radius cup of the balancer, wherein the anti-friction heat-resistant coating is made in the form of molybdenum disulfide.

[0010] Brief description of drawings.

[0011] The utility model is explained by drawings, where Fig. 1 shows a general view of a metal-ceramic brake lining for a high-speed electric train, Fig. 2 shows a view of the balancer in a ¾ view (from the front side), Fig. 3 shows a view of the balancer in a ¾ view (from the back side), Fig. 4 shows a view of a pentagonal friction segment in a ¾ view, Fig. 5 shows a view of a hexagonal friction segment in a ¾ view, Fig. 6 shows a view of a locking ring in a ¾ view, Fig. 7 shows a view of the supporting frame in a ¾ view (from the side of the friction segments), Fig. 8 shows a view of the supporting frame in a ¾ view (from the side of fastening the friction segments with locking rings), Fig. 9 shows a view of the balancer (side view in section), Fig. 10 shows a view of the connecting balancer unit with a supporting frame and a pentagonal friction segment (side view in section), in Fig.11 shows a view of the connecting unit of the balancer with a supporting frame and a hexagonal friction segment (side view in section).

[0012] The positions on the figures indicate:

[0013] 1 - supporting frame,

[0014] 2 - balancers,

[0015] 3 - mounting protrusion,

[0016] 4 - positioning balance convex pin,

[0017] 5 - friction segments,

[0018] 6 - ​​friction metal-ceramic material,

[0019] 7 - spherical frame with shank,

[0020] 8 - spherical frame support plate with shank,

[0021] 9 - radius cup of the balancer,

[0022] 10 - radius nests of the supporting frame,

[0023] 11 - retaining ring,

[0024] 12 - through hole on the balancer,

[0025] 13 - mounting hole in the supporting frame,

[0026] 14 - anti-friction coating,

[0027] 15 - contact surfaces of the balancer and the supporting frame,

[0028] 16 - contact surfaces of the balancer and friction segment,

[0029] 17 - shank.

[0030] Implementation of a utility model.

[0031] The metal-ceramic brake lining for a high-speed electric train (hereinafter referred to as the lining, the brake lining) is an assembled structure that includes a metal supporting frame 1, balancers 2, friction segments 5 and spring retaining rings 11. The spherical frame with a shank 7 of the friction segment 5 is installed in the corresponding radius cup of the balancer 9 with the possibility of sliding them relative to each other, and the balancers 9, which are a mechanism for swinging the friction elements, having a radius surface on the back side, are installed in the corresponding radius sockets 10 of the supporting frame with the possibility of sliding them relative to each other.

[0032] Friction segments 5, containing a layer of friction powder metal-ceramic material 6, are fixed on their own spherical metal frames with a shank 7 by sintering in a furnace with a protective or reducing atmosphere, the design of which consists of a support plate 8 and a shank 17, wherein the spherical part of the frame 7 is located in the support plate 8, above which the friction powder metal-ceramic material 6 is located.

[0033] Friction segments 5, depending on the shape of the support plate, are made of two types: pentagonal (in the amount of 12 pieces) and hexagonal (in the amount of 6 pieces), having, respectively, a pentagonal support plate and a hexagonal support plate. The tail of the friction segment 17 passes through a through hole on the balancer 12 and a mounting hole on the supporting frame 13, elastically connected to the supporting frame 1 by means of a spring retaining ring 11, fastening the friction segments 5, the balancers 2 and the supporting frame 1 together.

[0034] Balancers (equalizers, levers, regulators), containing an installation protrusion 3 and a convex pin 4 that positions the balancer, perform the function of intermediate frames between the metal supporting frame 1 and the friction segments 5. Three friction segments are installed on one balancer.

[0035] The balancer surface has an antifriction high-temperature coating 14, and the surfaces of the balancers are completely (in order to prevent the integrity of the coating from being damaged) covered with an antifriction heat-resistant material, which is molybdenum disulfide, which performs the function of lubrication between the surfaces 15, 16 that are in contact during sliding during the operation of the lining: the radius surface of the balancer on the back side (on the back side of the radius cup of the balancer) and the surface of the radius socket (recess) in the supporting frame, where the balancer is inserted, the surface of the spherical frame of the friction segment and the surface of the radius cup of the balancer.

[0036] Molybdenum disulfide coating (as a pure coating without binders) can be applied to balance weights as a thin layer by physical vapor deposition of MoS2, which provides maximum antifriction properties but requires more sophisticated equipment, or by ion-plasma spraying, which allows for the production of dense, well-adhered coatings with a thickness ranging from a few micrometers to hundreds of micrometers.

[0037] The metal-ceramic brake lining for high-speed electric trains works as follows.

[0038] The proposed lining relates to railway transport, namely to metal-ceramic brake linings, which are an integral part of the brake unit of the disc brake of a high-speed electric train.

[0039] Cipher metal-ceramic material linings are installed in the brake units of high-speed electric trains in order to ensure the required braking efficiency.

[0040] The brake pad is designed for use in conjunction with a steel ventilated brake disc.

[0041] The operation of the brake lining occurs as follows: when the electric train brakes, the linings are pressed on both sides of the brake disc installed on the axle of the electric train car, resulting in the electric train stopping.

[0042] When braking a high-speed electric train, the friction surface of the brake lining and disc heats up to high temperatures, reaching 800°C. This creates significant and rapidly changing dynamic loads on the brake lining, which during braking on high-speed trains can reach several tens of kilonewtons (kN). The specific value depends on the train's weight, speed, braking system efficiency, and other factors. For example, on high-speed trains such as the Sapsan or Allegro, during emergency braking, the dynamic load on a single brake lining can be approximately 20 kN or more.

[0043] Under high-speed train conditions, the brake lining may work in different environments (including dry, wet or even dirty).

[0044] The balancers used in the design of the brake lining, which are a mechanism for rocking the friction elements, have a radius surface on the back side, and which are installed in the corresponding radius sockets of the supporting frame, allow the brake lining, in the process of pressing against the brake disc and performing braking, to equalize the force of pressing the friction segments on the brake disc due to the rotation of the balancer, reduce the transfer of heat from the friction segments to the supporting frame, reducing its heating during the operation of the electric train, reduce the noise level by equalizing the pressure on the friction segments and thereby reducing the peak friction torque.

[0045] Anti-friction heat-resistant coating, which uses molybdenum disulfide, completely covers the surface of the balancers, performs the function of lubrication:

[0046] - between the contacting surfaces of the balancer during sliding during operation of the pad on the back side (from the back side of the balancer radius cup) and the surface of the radius socket (recess) in the supporting frame, where the balancer is inserted, helping to reduce the magnitude of the sliding friction force between the contacting surfaces 15, thereby reducing the wear of the contacting surfaces of the balancer and the supporting frame, which, in turn, allows to increase the cycles of their repeated use,

[0047] - between the surface of the spherical frame of the friction segment and the surface of the radius cup of the balancer, which helps to reduce the turning force (facilitate tilt) of the balancer when equalizing the pressure of the friction segments of the lining on the brake disc.

[0048] Molybdenum disulfide MoS2, used as a lubricant, is a bluish-gray powder with a metallic luster and exhibits good adsorption properties for most ferrous and non-ferrous metals. MoS2's lubricating properties are due to its distinct layered crystal structure (the distance between sulfur atoms in different crystal layers is almost four times greater than that within layers) and the strong polarization of sulfur atoms during friction.

[0049] Under different conditions, molybdenum disulfide exhibits a friction coefficient on steel in the range of 0.02-0.05, while the friction coefficient of graphite on steel is 0.04-0.3. Unlike graphite, molybdenum disulfide film performs effectively under extremely high loads. With increasing load and temperature, the friction coefficient of MoS2 decreases, ensuring its high load-bearing capacity, while the friction coefficient of graphite increases with increasing load and temperature.

[0050] The molybdenum disulfide film on the balance beam surface remains stable during high-temperature train braking, where significant heat is generated. It does not melt or evaporate. During operation, the film resists degradation.

[0051] For a high-speed train brake lining, three parameters are critical: film thickness, film uniformity, and adhesion (bonding to the substrate). In the proposed lining, molybdenum disulfide MoS2 forms a film up to 5 μm thick. This thickness allows for the creation of a thin yet durable protective layer that effectively reduces friction without adding weight to the structure. Unlike molybdenum disulfide, graphite is typically not applied as a separate thin film; it acts as a solid lubricant within the material. Due to its layered structure, MoS2 crystals effectively fill microroughness (pits, scratches) on the friction surface, forming a smooth sliding film. The thin-film structure is up to 5 μm thick; optimal strength, yield strength of approximately 3450 MPa. This contributes to the formation of a more uniform layer that performs reliably under a wide range of conditions.Molybdenum disulfide has good adhesion to metals, particularly steel, and exhibits superior adhesive properties compared to graphite. Strong molecular bonds between the sulfur atoms in the sulfur disulfide film and the metal backing (the supporting framework) ensure reliable adhesion from the film to the supporting framework of the brake pad, preventing wear under high loads, temperatures, and cyclic loading of the brake pad. MoS2 has an advantage over graphite in terms of adhesion to the metal base of the brake pad.

[0052] Molybdenum disulfide (MoS2) doesn't specifically require moisture to form a separating layer, so it can work in a vacuum and dry environment, in addition to humid conditions—the same conditions as the pad, where graphite isn't very effective. Under high loads and temperatures, MoS2 forms a strong film that effectively separates the metal and protects against scuffing. Graphite's lubricating effect depends on humidity; it only works more effectively in the presence of water vapor. However, at very high temperatures (approximately 450°C in air), graphite begins to oxidize, which degrades its properties.

[0053] For high-speed train brake linings, which are subject to extreme conditions (sharp and frequent braking, heat, varying humidity conditions, etc.), molybdenum disulfide (MoS2) is the preferred material. It provides a consistently low coefficient of friction, high load-bearing capacity, and performance under extreme temperature conditions. Graphite, under these conditions, is inferior in reliability and predictability of performance under intense heat and high loads; it is preferable for standard conditions where moisture is present.

[0054] The load-bearing capacity of solid lubricants is their ability to withstand high contact pressures in the friction zone without breaking down and without allowing direct metal-to-metal contact between mating parts (the maximum pressure at which the solid lubricant film maintains surface separation without entering the boundary friction or welding mode).

[0055] The increase in the efficiency of the lubricant as a result of using molybdenum disulfide as a material that performs the function of a lubricant is confirmed by the results of tests of the lining when using molybdenum disulfide as a lubricant covering the balance beams and when using graphite as a lubricant covering the balance beams under laboratory conditions, carried out by the applicant according to the relevant methods, where the indicators of the bearing capacity of the lubricant and the indicators of the coefficient of friction were compared, changing under the influence of a dynamic load comparable to the load to which the lining is subjected when braking a train at a temperature of about 600°C, 700°C, 800°C (varying the load and temperature).

[0056] The table below shows the test results.

[0057] Table

[0058] Parameter Molybdenum disulfide (MoS2) Graphite 10 kN (t = 600°C) 15 kN (t = 700°C) 20 kN (t = 800°C) 10 kN (t = 600°C) 15 kN (t = 700°C) 20 kN (t = 800°C) Coefficient of friction under changing dynamic load and temperature 0.02 (in dry environment) 0.03 (in dry environment) 0.05 (in dry environment) 0.04 (in dry environment) 0.1 (in dry environment) 0.3 (in dry environment) Bearing capacity up to 2800 MPa up to 200 MPa

[0059] Molybdenum disulfide film works effectively under extremely high loads, while graphite's friction coefficient increases with increasing load.

[0060] Thus, the advantages of molybdenum disulfide over graphite are that it operates stably under extremely high loads, effectively prevents increased wear and tear, provides long-term lubrication under aggressive environmental conditions, has higher antifriction properties and has greater load-bearing capacity.

Claims

A metal-ceramic brake lining for a high-speed electric train, comprising a supporting frame and friction segments mounted on the supporting frame by means of balance beams; the spherical frame of the friction segment is mounted in a corresponding radius cup of the balance beam with the ability to slide relative to each other, and the balance beams, having a radius surface on the back side, are mounted in corresponding radius seats of the supporting frame with the ability to slide relative to each other; the surface of the balance beams has an antifriction heat-resistant coating that performs the function of lubrication between the radius surface of the balance beam on the back side and the corresponding surface of the radius seat of the supporting frame, the surface of the spherical frame of the friction segment and the surface of the radius cup of the balance beam, which are in contact during sliding, characterized in that the antifriction heat-resistant coating is made in the form of molybdenum disulfide.

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