High-speed train wheel-mounted brake disc and preparation method thereof

Abstract

The application discloses a high-speed train wheel-mounted brake disc, which comprises two carbon-toughened ceramic composite disc bodies, the two disc bodies are symmetrically arranged on two sides of a wheel, the disc body comprises a plurality of heat dissipation ribs, the plurality of heat dissipation ribs are arranged at intervals in the circumferential direction of the disc body, the heat dissipation ribs comprise first heat dissipation ribs, second heat dissipation ribs and third heat dissipation ribs which are different in shape, the first heat dissipation ribs are uniformly distributed in the circumferential direction of the disc body, the second heat dissipation ribs or the third heat dissipation ribs are located between adjacent first heat dissipation ribs, and the second heat dissipation ribs and the third heat dissipation ribs are alternately distributed in the circumferential direction of the disc body, the third heat dissipation ribs comprise first bosses and second bosses which are arranged at intervals, and the second heat dissipation ribs and the third heat dissipation ribs are also uniformly distributed in the circumferential direction of the disc body. Radial and circumferential ventilation grooves are formed on the heat dissipation ribs, thereby forming a three-dimensional heat dissipation system with circumferential and radial ventilation channels.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of rail vehicle brake disc, in particular to a high-speed train wheel-mounted brake disc and a preparation method thereof. BACKGROUND

[0002] At present, the traditional steel brake disc is applied to high-speed trains with a speed of 350 km / h. When emergency braking, the disc surface temperature is close to the material limit, and long-term use is prone to hot spot and thermal fatigue crack problems. Moreover, the traditional steel brake disc is heavy, which is not conducive to the overall weight reduction requirement of the train, especially the reduction of the train's unsprung mass. With the continuous improvement of vehicle running speed, higher requirements are put forward for reducing the bogie unsprung mass from the aspects of reducing operating energy consumption and braking energy. Therefore, it is urgent to develop a light and high-heat-resistant brake disc to match the development trend of high speed and light weight in the rail transportation industry.

[0003] Some existing technologies use a carbon ceramic composite material to manufacture a train brake disc. The carbon ceramic composite material is brittle, has low strength and weak shear resistance, and is difficult to design identically according to the heat dissipation fin structure of the traditional steel wheel-mounted brake disc. Currently, there are mainly two structural methods in the industry, namely, an integrated carbon ceramic wheel disc and a "sandwich" combined carbon ceramic wheel disc.

[0004] The existing technology CN209925468U discloses a carbon ceramic wheel-mounted brake disc suitable for high-speed motor trains, which adopts a "sandwich" combined structure, and the carbon ceramic friction body and the isolation support body are fixed by layering and connecting. The surface of the isolation support body facing the carbon ceramic friction body is provided with a heat insulation ceramic coating. The isolation support body has a plurality of connection areas along the circumferential direction, and the carbon ceramic friction body and the isolation support body are connected and fixed by the connecting parts in the connection areas. However, this technical solution does not consider the heat conduction and heat dissipation effect of the isolation support body, and the heat insulation support body has high processing difficulty and manufacturing cost, and the overall structure has limited weight reduction effect. Moreover, the carbon ceramic friction body has high brake temperature rise during high-speed braking, which is difficult to match the appropriate mating brake pad.

[0005] The existing technology CN209026055U discloses a high-speed train composite material wheel-mounted brake disc, which adopts an integrated carbon ceramic structure, and the disc body connecting surface is provided with two large block-shaped heat dissipation fin bosses which are alternately and uniformly distributed along the circumferential direction. However, this design does not consider the stress state and heat dissipation performance difference of different heat dissipation fin bosses, which is prone to cause local stress too large problem, and does not involve the fastening connection scheme between the brake disc and the wheel.

[0006] In order to solve the problems of high brake temperature rise, difficult connection with wheels, limited weight reduction effect and the like of the composite brake disc of the high-speed train with a speed of 350 km / h or above, an integrated carbon-toughened disc body with good ventilation and heat dissipation performance, reliable fastening connection with wheels and easy processing is needed to be designed, and a preparation method of the carbon-toughened composite material with matched thermal physical properties and mechanical properties is needed to be designed, so that the composite brake disc has good heat dissipation and weight reduction effect in structure and material.

[0007] In view of the above technical problems, the present application is proposed. SUMMARY

[0008] The main purpose of the present application is to provide a high-speed train wheel-mounted brake disc and a preparation method thereof, which is used to solve the problems of high brake temperature rise, difficult heat dissipation, limited weight reduction effect and the like of the composite brake disc of the high-speed train from the aspects of structure and material.

[0009] In order to achieve the above purpose, according to one aspect of the present application, a high-speed train wheel-mounted brake disc is provided, which comprises two carbon-toughened composite disc bodies, the two disc bodies are symmetrically installed on both sides of the wheel, the disc body comprises a plurality of heat dissipation ribs, the plurality of heat dissipation ribs are arranged at intervals along the circumferential direction of the disc body, and the heat dissipation ribs comprise first heat dissipation ribs, second heat dissipation ribs and third heat dissipation ribs which are different in shape.

[0010] The first heat dissipation ribs are uniformly distributed in the circumferential direction of the disc body, the second heat dissipation ribs or the third heat dissipation ribs are located between adjacent first heat dissipation ribs, and the second heat dissipation ribs and the third heat dissipation ribs are alternately distributed in the circumferential direction of the disc body.

[0011] The third heat dissipation rib comprises a first rib and a second rib which are arranged at intervals, and the second heat dissipation rib and the third heat dissipation rib are also uniformly distributed in the circumferential direction of the disc body.

[0012] Further, the first heat dissipation rib has a fastener through hole, the fastener through hole is located at the middle position of the radial direction of the disc body, the contour shape of the first heat dissipation rib is a hexagon, the hexagon comprises opposite top edges and bottom edges, and the top edges and the bottom edges are both perpendicular to the radial direction of the disc body.

[0013] Further, the second heat dissipation rib comprises two edge ribs and a connecting rib, the two edge ribs are respectively located on both sides of the connecting rib along the circumferential direction of the disc body, the length direction of the two edge ribs is along the radial direction of the disc body, and the length of the connecting rib along the radial direction of the disc body is less than that of the edge rib.

[0014] Further, the side protrusions comprise first circumferential ventilation grooves, the first circumferential ventilation grooves comprise outer circumferential ventilation grooves and inner circumferential ventilation grooves, and the outer circumferential ventilation grooves and the inner circumferential ventilation grooves are located on two sides of the connecting protrusions in the radial direction of the disc body.

[0015] Further, the lengths of the first protrusions and the second protrusions extend in the radial direction of the disc body, and the first protrusions and the second protrusions comprise second circumferential ventilation grooves, and the second circumferential ventilation grooves respectively pass through the first protrusions and the second protrusions in the circumferential direction of the disc body.

[0016] Further, the first protrusions and the second protrusions are isosceles trapezoids, the isosceles trapezoids comprise symmetrical axes and two oblique sides, the included angle β between the two oblique sides of the isosceles trapezoid is ≤4°, and the included angle α between the symmetrical axes of the first protrusions and the second protrusions is ≤10°.

[0017] Further, the wheel brake disc further comprises a fastener, a first heat insulation bushing and a second heat insulation bushing, the fastener through hole is a stepped hole, the fastener passes through the fastener through holes of the disc body and the wheel on both sides to fasten the disc body and the wheel, and the first heat insulation bushing and the second heat insulation bushing are respectively located between the stepped faces of the fastener through holes on both sides and the fastener.

[0018] The above technical solutions of the application at least achieve the following beneficial effects:

[0019] 1. The disc body of the brake disc can play a good supporting and positioning role through the design of three kinds of heat dissipation ribs protrusions which are alternately and uniformly distributed in the circumferential direction; the radial and circumferential ventilation grooves formed on the heat dissipation rib protrusions form a three-dimensional heat dissipation system with circumferential and radial through ventilation air ducts, which can quickly cool the brake heat.

[0020] 2. The brake disc can increase the strength of the support surface of the fastener through hole through the design of the shape structure of the first heat dissipation rib protrusion, the width of the middle section in the radial direction is large, and the width of the two sides in the radial direction is small, which can increase the radial ventilation volume while ensuring the strength and rigidity of the first heat dissipation rib protrusion.

[0021] 3. The brake disc can enhance the shear resistance of the positioning pin groove through the design of the shape structure of the second heat dissipation rib protrusion, and the left-right symmetrical structure of the second heat dissipation rib protrusion enhances the shear resistance of the positioning pin groove.

[0022] 4. The brake disc can greatly increase the radial and circumferential ventilation volumes and improve the stress distribution state of the disc body through the design of the shape structure of the third heat dissipation rib protrusion, the use of two independent variable-width trapezoidal heat dissipation ribs, and the use of the second circumferential ventilation groove with a large width.

[0023] 5、The brake disc of the present application directly hinders the heat transfer from the disc body to the bolts by using the heat insulation bushing, thereby greatly reducing the axial force attenuation during braking; meanwhile, the lock nut is used to greatly improve the fastening connection reliability.

[0024] 6、The brake disc of the present application is designed as a hexagonal flange variable cross-section structure, and the nut is also designed as a hexagonal flange structure, thereby increasing the pressure bearing area of the fastening connection, ensuring the uniform and low pressure distribution on the surface of the carbon ceramic disc body, and solving the problem of excessive stress at the bolt hole of the carbon ceramic disc body.

[0025] 7、The disc body of the brake disc of the present application adopts an integrated carbon ceramic structure, which can reduce the weight by more than 2 / 3 compared with the existing steel brake disc, greatly reducing the unsprung mass of the high-speed train and meeting the light weight trend of the high-speed train.

[0026] In order to achieve the above-mentioned purpose, according to another aspect of the present application, a preparation method of the wheel-mounted brake disc is provided, comprising the following steps: a carbon fiber preform preparation step, making a no-woven cloth and a net tire, introducing a carbon fiber bundle after cyclically stacking the no-woven cloth and the net tire to obtain the carbon fiber preform; a chemical vapor deposition carbon step, putting the carbon fiber preform into a chemical vapor deposition furnace for chemical vapor deposition carbon treatment to obtain a first low-density carbon carbon blank; a resin impregnation and pyrolysis step, putting the first low-density carbon carbon blank into a resin impregnation and pyrolysis furnace to obtain a second low-density carbon carbon blank; a high-temperature graphitization step, putting the second low-density carbon carbon blank into a high-temperature heat treatment furnace for high-temperature graphitization treatment; a mechanical processing step, mechanically processing the second low-density carbon carbon blank after high-temperature graphitization treatment to make it have the shape of the wheel-mounted brake disc; and a molten silicon infiltration step, putting the second low-density carbon carbon blank after mechanical processing into a silicon infiltration furnace for molten silicon infiltration treatment to obtain the wheel-mounted brake disc of carbon ceramic composite material.

[0027] Further, the density of the carbon fiber preform is 0.4-0.55 g / cm 3 , the density of the first low-density carbon carbon blank is 0.8-1.0 g / cm 3 , the density of the second low-density carbon carbon blank obtained in the resin impregnation and pyrolysis step is 1.3-1.5 g / cm 3 , and the material density of the wheel-mounted brake disc prepared through the molten silicon infiltration step is 2.0-2.2 g / cm 3The carbon ceramic composite material brake disc prepared by the method has excellent matching of mechanical properties and thermophysical properties, and has good structural strength and heat conduction performance, and has low mass density.

[0028] Further, in the carbon fiber preform preparation step, single-layer weftless cloth is made of carbon fibers, and the fiber orientation is 0° and 90° respectively; the web tire is made of chopped carbon fibers, the length of the chopped carbon fibers is 30-100mm; the layers are stacked in the order of 0° weftless cloth, web tire, 90° weftless cloth, web tire, 0° weftless cloth, and the interlayer density in the stacking direction is 10-25 layers / cm; the carbon fiber bundle is introduced in the stacking direction at a needling density of 20-30 needles / cm 2 The volume ratio of the web tire to the weftless cloth is 1:1-1:3.

[0029] The above technical scheme of the application at least realizes the following beneficial effects: the carbon ceramic composite material brake disc preparation method adopts a combined process of chemical vapor infiltration, resin impregnation pyrolysis and reaction melting infiltration, and the obtained carbon ceramic composite material has excellent matching of mechanical properties and thermophysical properties, which ensures that the disc body has good structural strength and heat conduction performance, and has low mass density. BRIEF DESCRIPTION OF DRAWINGS

[0030] The drawings accompanying the specification of the application form part of the application and serve to provide further understanding of the application, and the illustrative embodiments of the application and their description serve to explain the application, and do not constitute an improper limitation on the application. In the drawings:

[0031] Figure 1 A brake disc and wheel assembly schematic diagram of an embodiment of the application is shown;

[0032] Figure 2 A brake disc and wheel assembly front view of an embodiment of the application is shown;

[0033] Figure 3 A Figure 2 A-A cross-sectional view of the application is shown;

[0034] Figure 4 A Figure 2 B-B cross-sectional view of the application is shown;

[0035] Figure 5 A brake disc schematic diagram of an embodiment of the application is shown;

[0036] Figure 6A first heat dissipation rib boss front view of the embodiment of the present application is shown;

[0037] Figure 7 A second heat dissipation rib boss front view of the embodiment of the present application is shown;

[0038] Figure 8 A third heat dissipation rib boss front view of the embodiment of the present application is shown;

[0039] Figure 9 A brake disc front view of the embodiment of the present application is shown;

[0040] Figure 10 A first heat dissipation rib boss front view of the embodiment of the present application is shown; Figure 9 A C-C cross-sectional view of the embodiment of the present application is shown;

[0041] Figure 11 A second heat dissipation rib boss front view of the embodiment of the present application is shown; Figure 9 A D-D cross-sectional view of the embodiment of the present application is shown;

[0042] Figure 12 A third heat dissipation rib boss front view of the embodiment of the present application is shown; Figure 9 A E-E cross-sectional view of the embodiment of the present application is shown;

[0043] Figure 13 A fourth heat dissipation rib boss front view of the embodiment of the present application is shown; Figure 9 A F-F cross-sectional view of the embodiment of the present application is shown;

[0044] Figure 14 A first heat dissipation rib boss front view of the embodiment of the present application is shown;

[0045] Figure 15 A second heat dissipation rib boss front view of the embodiment of the present application is shown;

[0046] Figure 16 A bolt schematic view of the embodiment of the present application is shown;

[0047] Figure 17 A nut schematic view of the embodiment of the present application is shown;

[0048] Figure 18 A brake disc and wheel assembly explosion view of the embodiment of the present application is shown.

[0049] Wherein, the above figures include the following reference signs:

[0050] 1. Wheel; 2. Disc; 21. First cooling rib boss; 211. Fastener through hole; 212. Top edge; 213. Bottom edge; 22. Second cooling rib boss; 221. Locating pin groove; 222. Outer circumferential ventilation groove; 223. Inner circumferential ventilation groove; 224. Side boss; 225. Connecting boss; 226. Radial ventilation channel; 23. Third cooling rib boss; 231. Second circumferential ventilation groove; 232. First boss; 233. Second boss; 3. First heat insulation bushing; 4. Bolt; 5. Nut; 6. Second heat insulation bushing; 7. Locating pin. Detailed Implementation

[0051] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0052] The present invention will be further described in detail below with reference to specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed by the present invention. The term "comprising" indicates the presence of a feature, but does not exclude the presence or addition of one or more other features. The terms "lateral," "upper," "lower," "front," "rear," "left," "right," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the purpose of description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0053] In this description, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances. Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0054] Example:

[0055] This invention proposes a wheel-mounted brake disc for high-speed trains, such as... Figures 1-4 As shown, the device includes two carbon-ceramic composite discs 2, which are symmetrically mounted on both sides of the wheel 1. It also includes fasteners and positioning pins 7. The discs 2 have fastener through holes 211, and the two discs 2 are connected to the wheel 1 by fasteners. Positioning pins 7 are provided between the discs 2 and the wheel 1 for positioning the discs 2.

[0056] The disc body of the brake disc of the present application adopts an integrated carbon ceramic structure, which can reduce weight by more than 2 / 3 compared with the existing steel brake disc, greatly reduces the unsprung mass of the high-speed train, and meets the trend of lightening of the high-speed train.

[0057] As shown in Figure 5 The disc body 2 includes a plurality of heat dissipation ribs, which are arranged at intervals in the circumferential direction of the disc body 2. The heat dissipation ribs include first heat dissipation ribs 21, second heat dissipation ribs 22, and third heat dissipation ribs 23, which have different shapes. The heat dissipation ribs mainly play a supporting and positioning role for the carbon ceramic disc body, while ensuring ventilation and heat dissipation, and also ensuring a certain strength and rigidity of the heat dissipation ribs.

[0058] Specifically, the first heat dissipation ribs 21 are uniformly distributed in the circumferential direction of the disc body 2, the second heat dissipation ribs 22 or the third heat dissipation ribs 23 are located between adjacent first heat dissipation ribs 21, and the second heat dissipation ribs 22 and the third heat dissipation ribs 23 are alternately distributed in the circumferential direction of the disc body 2. The third heat dissipation ribs 23 include first protrusions 232 and second protrusions 233 which are distributed at intervals, and the second heat dissipation ribs 22 and the third heat dissipation ribs 23 are also uniformly distributed in the circumferential direction of the disc body 2.

[0059] Preferably, in the present embodiment, the first heat dissipation ribs 21 are uniformly distributed at intervals of 30° with respect to the center of the disc body 2 in the circumferential direction of the disc body 2, and the second heat dissipation ribs 22 and the third heat dissipation ribs 23 are uniformly distributed at intervals of 60° with respect to the center of the disc body 2 in the circumferential direction of the disc body 2.

[0060] As shown in Figure 5 and Figure 6 The first heat dissipation ribs 21 have fastener through holes 211, which are located at the middle position in the radial direction of the disc body 2. The profile shape of the first heat dissipation ribs 21 is hexagonal. In the present application, the profile shape refers to the external profile shape of each heat dissipation rib observed in the axial direction of the disc body.

[0061] As shown in Figure 6 The profile hexagonal shape of the first heat dissipation ribs 21 includes opposite top edges 212 and bottom edges 213, wherein the top edges 212 are close to the radial outer side of the disc body, and the bottom edges 213 are close to the radial inner side of the disc body. Preferably, the top edges 212 and the bottom edges 213 are both perpendicular to the radial direction of the disc body 2.

[0062] Specifically, the length of the first heat dissipation rib boss 21 along the radial direction of the disc body 2, i.e. the distance between the top edge 212 and the bottom edge 213, is greater than the maximum width b of the first heat dissipation rib boss 21, which is located at the middle position of the radial direction of the disc body 2. That is, the maximum width b of the first heat dissipation rib boss 21 is located on both sides of the fastener through hole 211 in the circumferential direction. The minimum length of the top edge 212 and the bottom edge 213 is a, and b / a≤4. Preferably, the profile of the first heat dissipation rib boss 21 is a symmetrical figure, and the lengths of the top edge 212 and the bottom edge 213 are equal. The strength of the carbon ceramic material is low, and the shear resistance is weak. The length of the top edge 212 and the bottom edge 213 is limited to avoid being too small, so that the strength of the first heat dissipation rib boss 21 at this position is insufficient.

[0063] In some embodiments, the top edge 212 and the bottom edge 213 of the first heat dissipation rib boss 21 profiled as a hexagon can be machined as an arc segment at this position, and the length of the top edge 212 and the bottom edge 213 is considered as the chord length of the arc segment.

[0064] The brake disc of the present application increases the strength of the support surface of the fastener through hole by designing the shape and structure of the first heat dissipation rib boss, which has a large width in the middle section of the radial direction and a small width on both sides of the radial direction, thereby increasing the radial ventilation amount while ensuring the strength and rigidity of the first heat dissipation rib boss.

[0065] As shown in Figure 5 and Figure 7 , the second heat dissipation rib boss 22 includes two edge bosses 224 and a connecting boss 225, the two edge bosses 224 are respectively located on both sides of the connecting boss 225 along the circumferential direction of the disc body 2, the length direction of the two edge bosses 224 is along the radial direction of the disc body 2, and the length of the connecting boss 225 along the radial direction of the disc body 2 is smaller than that of the edge boss 224. Preferably, the profile of the second heat dissipation rib boss 22 is designed as the shape shown in Figure 7 .

[0066] As shown in Figure 9 and Figure 11 , the connecting boss 225 includes a positioning pin slot 221, the positioning pin slot 221 penetrates through the connecting boss 225 along the radial direction of the disc body, forming a radial ventilation channel 226. Preferably, the second heat dissipation rib boss 22 is symmetrical relative to the radial ventilation channel 226. As shown in Figure 18 , after the positioning pin 7 is placed in the positioning pin slot 221, the end faces of both ends of the positioning pin 7 form a surface contact with the inner wall of the positioning pin slot 221.

[0067] As shown in Figure 9 and Figure 12As shown, the edge boss 224 includes a first circumferential vent slot, which penetrates the edge boss 224 along the circumferential direction of the disc body 2. Preferably, the first circumferential vent slot includes an outer circumferential vent slot 222 and an inner circumferential vent slot 223. In the radial direction of the disc body 2, the outer circumferential vent slot 222 and the inner circumferential vent slot 223 are respectively located on the two sides of the connecting boss 225. In other embodiments of the present application, the first circumferential vent slot can also have one or more.

[0068] In addition, as Figure 7 As shown, preferably, the edge boss 224 is profiled as an isosceles trapezoidal structure with two sides and a symmetry axis, and the top and bottom edges of the profile are perpendicular to the radial direction of the disc body, and preferably the two sides and the symmetry axis are all coincident with the radial direction of the disc body. The included angle β between the two sides is ≤4°, and the included angle α between the symmetry axes of the two edge bosses 224 is ≤10°.

[0069] The brake disc of the present application has a radial venting channel formed by the positioning pin slot, a circumferential venting channel, and a left-right symmetrical structure of the second heat dissipation rib boss, which enhances the shear resistance of the positioning pin slot.

[0070] As shown in Figure 5 and Figure 8 The first boss 232 and the second boss 233 are arranged at intervals, and the length direction of each of the first boss 232 and the second boss 233 extends in the radial direction of the disc body 2. The first boss 232 and the second boss 233 each include a second circumferential vent slot 231, which penetrates the first boss 232 and the second boss 233 respectively along the circumferential direction of the disc body 2.

[0071] As shown in Figure 9 and Figure 13 The width of the second circumferential vent slot 231 in the radial direction of the disc body 2 is more than half the length of the first boss 232 and the second boss 233 in the radial direction.

[0072] As shown in Figure 8 Preferably, the first boss 232 and the second boss 233 are profiled as an isosceles trapezoidal structure with two sides and a symmetry axis, and preferably the two sides and the symmetry axis are all coincident with the radial direction of the disc body 2. The included angle β between the two sides is ≤4°. The included angle α between the symmetry axis of the first boss 232 and the symmetry axis of the second boss 233 is ≤10°.

[0073] The brake disc of the present application has a radial venting channel formed by the positioning pin slot, a circumferential venting channel, and a left-right symmetrical structure of the second heat dissipation rib boss, which enhances the shear resistance of the positioning pin slot.

[0074] It should be noted that the profile shape of the first, second and third heat dissipation ribs in the drawings of the present application is only a preferred schematic, and the present application is not limited to this shape design.

[0075] In summary, on the disc body 2 of the present application, the second heat dissipation rib boss 22 has a radial ventilation channel 226, a radial ventilation channel is also provided between the first boss 232 and the second boss 233 of the third heat dissipation rib boss, and a radial ventilation channel is provided between the first heat dissipation rib boss 21, the second heat dissipation rib boss 22 and the third heat dissipation rib boss 23. A first circumferential ventilation groove is provided on the second heat dissipation rib boss 22, including an outer circumferential ventilation groove 222 and an inner circumferential ventilation groove 223, and a second circumferential ventilation groove 231 is provided on the third heat dissipation rib boss 23. These radial ventilation channels and circumferential ventilation channels are interconnected to form a three-dimensional heat dissipation system.

[0076] The disc body of the brake disc of the present application is designed to have three types of heat dissipation rib bosses alternately and uniformly distributed in the circumferential direction, which can play a good supporting and positioning role. Radial and circumferential ventilation grooves are provided on the heat dissipation rib bosses to form a three-dimensional heat dissipation system with radial and circumferential ventilation channels, which can quickly cool the brake heat. It has been verified that the carbon ceramic disc body of the brake disc designed according to the present application has a maximum temperature of <900℃ when the brake disc is subjected to emergency braking at 400km / h.

[0077] As shown in Figure 3 , the wheel-mounted brake disc further comprises a first heat insulation bushing 3 and a second heat insulation bushing 6. In combination with Figure 10 , the fastener through hole 211 is a stepped hole, and the fastener passes through the fastener through hole 211 of the wheel 1 and the disc body 2 on both sides to fasten the disc body 2 and the wheel 1, and the first heat insulation bushing 3 and the second heat insulation bushing 6 are respectively located between the stepped surface of the fastener through hole 211 on both sides and the fastener.

[0078] In addition, the fastener comprises a bolt 4 and a nut 5. As shown in Figure 16 and 17 , the bolt 4 is a hexagonal flange bolt, and the shank section of the bolt 4 has different outer diameters in the extension direction. The nut 5 is a hexagonal flange lock nut. The brake disc of the present application is designed to have a hexagonal flange variable cross-section structure for the bolt and a hexagonal flange structure for the nut, which increases the pressure bearing area of the fastening connection, ensures uniform and low pressure distribution on the surface of the carbon ceramic disc body, and solves the problem of excessive stress at the bolt hole of the carbon ceramic disc body.

[0079] In combination with Figure 14 and Figure 15As shown, the first thermal insulation bushing 3 is located at the side of the bolt head of the bolt 4, the second thermal insulation bushing 6 is located at the side of the nut 5, and the length of the first thermal insulation bushing 3 is greater than that of the second thermal insulation bushing 6. The two side support surfaces of the first thermal insulation bushing 3 and the second thermal insulation bushing 6 are provided with a thermal insulation ceramic coating, so as to ensure that the temperature of the carbon ceramic material is not directly transmitted to the bolt and the nut during braking. The brake disc of the application directly hinders the heat of the disc body from being transmitted to the bolt by adopting the thermal insulation bushing, thereby greatly reducing the axial force attenuation in the braking process; at the same time, the lock nut is adopted, so as to greatly improve the fastening connection reliability.

[0080] The application further provides a preparation method of the high-speed train wheel-mounted brake disc, and the carbon ceramic composite material with matched thermal physical properties and mechanical properties can be obtained by adopting the method, and the structure design of the wheel-mounted brake disc is combined with the above description, so that the wheel-mounted brake disc has good heat dissipation and weight reduction effects in terms of structure and material.

[0081] Specifically, the preparation method comprises the following steps:

[0082] S1, a carbon fiber preform preparation step, using carbon fibers to make a single-layer weftless cloth and a net tire, and then introducing carbon fiber bundles to obtain a carbon fiber preform with a density of 0.4-0.55 g / cm 3 .

[0083] Preferably, in the carbon fiber preform preparation step, 12K polyacrylonitrile-based T300 carbon fibers are used to make a single-layer weftless cloth, and the fiber orientations are 0° and 90° respectively. 12K polyacrylonitrile-based T700 chopped carbon fibers are used to make a net tire, and the length of the chopped carbon fibers is 30-100 mm. The weftless cloth, the net tire, the weftless cloth, the net tire and the weftless cloth are sequentially and cyclically laminated in the order of 0° weftless cloth, net tire, 90° weftless cloth, net tire and 0° weftless cloth, and the interlayer density in the lamination direction is 10-25 layers / cm.

[0084] Then, the carbon fiber bundles are introduced in the lamination direction by needling at a needling density of 20-30 needles / cm 2 to obtain a 2.5-dimensional needled carbon fiber preform, and the volume ratio of the net tire to the weftless cloth in the carbon fiber preform is in the range of 1:1-1:3.

[0085] S2, a chemical vapor deposition carbon step, the carbon fiber preform is placed in a chemical vapor deposition furnace, and chemical vapor deposition carbon is carried out at a temperature of 900-1100℃ to obtain a first low-density carbon carbon body, also called a low-density C / C body, with a density of 0.8-1.0 g / cm 3 .

[0086] S3, resin impregnation and pyrolysis step, the first low-density carbon carbon body is put into a resin impregnation and pyrolysis furnace, and a second low-density carbon carbon body with a density of 1.3-1.5 g / cm 3 is obtained.

[0087] S4, high-temperature graphitization step, the second low-density carbon carbon body after the resin impregnation and pyrolysis step is put into a high-temperature heat treatment furnace, and high-temperature graphitization treatment is performed at a temperature of 1800-2000℃.

[0088] S5, mechanical processing step, the second low-density carbon carbon body after the high-temperature graphitization treatment is subjected to mechanical processing, so as to have the shape of the wheel-mounted brake disc in the present application, i.e., to be processed into the shape and structure as shown in Figure 5 .

[0089] S6, silicon melt infiltration step, the second low-density carbon carbon body after the mechanical processing is put into a silicon infiltration furnace, and silicon melt infiltration treatment is performed at a temperature of 1550-1700℃, so as to finally obtain the wheel-mounted brake disc of the carbon ceramic composite material.

[0090] The wheel-mounted brake disc material prepared through the silicon melt infiltration step has a density of 2.0-2.2 g / cm 3 , an open porosity of ≤3.5%, a mass percentage of SiC of 35-50%, a mass percentage of C of 20-60%, and a mass percentage of Si of ≤10%; the disc body material has a tensile strength of ≥100 MPa, a compressive strength of ≥300 MPa, a bending strength of ≥160 MPa, an interlaminar shear strength of ≥30 MPa, and a thermal conductivity of ≥35 W / (m·K).

[0091] In other embodiments, the disclosure of the plurality of steps and functions disclosed in the specification and claims can not be interpreted as in a specific order, and the disclosure of the plurality of steps and functions does not limit them to a specific order, unless these steps and functions cannot be interchanged due to technical reasons. In addition, in the embodiments, a single step can include or can be divided into a plurality of sub-steps, and other steps can be added between the disclosed steps.

[0092] The preparation method of the carbon ceramic composite brake disc of the present application adopts a combined process of chemical vapor infiltration, resin impregnation and pyrolysis, and reaction melt infiltration, and the obtained carbon ceramic composite material has excellent matching of mechanical properties and thermophysical properties, so as to ensure that the disc body has good structural strength and thermal conductivity, and at the same time has a relatively low mass density.

[0093] In summary, from the above description, it can be seen that the above embodiments of the present application achieve the following technical effects:

[0094] 1、The brake disc body of the application can play a good supporting and positioning role through the design of three kinds of heat dissipation ribs bosses alternately and uniformly distributed in the circumferential direction; the radial and circumferential ventilation grooves are formed on the heat dissipation rib bosses to form a three-dimensional heat dissipation system with a circumferential and radial through ventilation air duct, which can quickly cool the brake heat.

[0095] 2、The brake disc of the application can increase the support surface strength of the fastener through hole by designing the shape structure of the first heat dissipation rib boss, the width of the middle section in the radial direction is large, the width of the two sides in the radial direction is small, which can increase the radial ventilation volume while ensuring the strength and rigidity of the first heat dissipation rib boss.

[0096] 3、The brake disc of the application can enhance the shear resistance of the positioning pin groove through the design of the shape structure of the second heat dissipation rib boss, which forms a radial ventilation channel and also has a circumferential ventilation channel, and the left-right symmetrical structure of the second heat dissipation rib boss enhances the shear resistance of the positioning pin groove.

[0097] 4、The brake disc of the application can greatly increase the radial and circumferential ventilation volume and also improve the stress distribution state of the disc body through the design of the shape structure of the third heat dissipation rib boss, which adopts two independent variable-width trapezoidal heat dissipation ribs and has a second circumferential ventilation groove with a large width.

[0098] 5、The brake disc of the application can greatly reduce the axial force decay in the braking process by using a heat insulation bushing to directly block the heat transfer from the disc body to the bolt, and also greatly improves the fastening connection reliability by using a lock nut.

[0099] 6、The brake disc of the application can solve the problem of excessive stress at the bolt hole of the carbon ceramic disc body by designing the bolt into a hexagonal flange variable cross-section structure and the nut into a hexagonal flange structure, which increases the pressure bearing area of the fastening connection and ensures that the surface pressure distribution of the carbon ceramic disc body is uniform and the pressure is low.

[0100] 7、The preparation method of the carbon ceramic composite brake disc of the application adopts a combined process of chemical vapor infiltration, resin impregnation and pyrolysis, and reaction infiltration, which has excellent matching of mechanical properties and thermophysical properties of the obtained carbon ceramic composite material, ensuring that the disc body has good structural strength and thermal conductivity, while having a relatively low mass density.

[0101] 8、The disc body of the brake disc of the application adopts an integrated carbon ceramic structure, which can reduce the weight by more than 2 / 3 compared with the existing steel brake disc, greatly reducing the unsprung mass of the high-speed train and meeting the trend of lightweight of high-speed trains.

[0102] The above merely provides the preferred embodiments of the present application, and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the principles and technical scope of the present application shall fall into the scope of the present application.

Claims

1. A high-speed train wheel-mounted brake disc, comprising two carbon-ceramic composite disc bodies (2), the two disc bodies (2) being symmetrically mounted on both sides of a wheel (1), characterized in that: The disk body (2) includes a plurality of heat dissipation rib protrusions, which are arranged at intervals along the circumference of the disk body (2). The heat dissipation rib protrusions include a first heat dissipation rib protrusion (21), a second heat dissipation rib protrusion (22), and a third heat dissipation rib protrusion (23) with different shapes. The first heat dissipation fin protrusion (21) is evenly distributed in the circumferential direction of the disk body (2). The second heat dissipation fin protrusion (22) or the third heat dissipation fin protrusion (23) is located between adjacent first heat dissipation fin protrusions (21), and the second heat dissipation fin protrusion (22) and the third heat dissipation fin protrusion (23) are alternately distributed in the circumferential direction of the disk body (2). The third heat dissipation fin protrusion (23) includes a first protrusion (232) and a second protrusion (233) distributed at intervals. The second heat dissipation fin protrusion (22) and the third heat dissipation fin protrusion (23) are also evenly distributed in the circumferential direction of the disk body (2). The outline shape of the first heat dissipation fin protrusion (21) is hexagonal. The hexagon includes a top edge (212) and a bottom edge (213) that are opposite each other. The top edge (212) and the bottom edge (213) are both perpendicular to the radial direction of the disk body (2).

2. The wheel-mounted brake disc according to claim 1, characterized in that: The first heat dissipation fin boss (21) has a fastener through hole (211), which is located at the center of the radial direction of the disk body (2).

3. The wheel-mounted brake disc according to claim 2, characterized in that: The second heat dissipation fin protrusion (22) includes two side protrusions (224) and a connecting protrusion (225). The two side protrusions (224) are located on both sides of the connecting protrusion (225) along the circumference of the disk body (2). The length direction of the two side protrusions (224) is along the radial direction of the disk body (2). The length of the connecting protrusion (225) along the radial direction of the disk body (2) is less than that of the side protrusions (224).

4. The wheel-mounted brake disc according to claim 3, characterized in that: The side boss (224) includes a first circumferential ventilation groove, which includes an outer circumferential ventilation groove (222) and an inner circumferential ventilation groove (223). In the radial direction of the disc body (2), the outer circumferential ventilation groove (222) and the inner circumferential ventilation groove (223) are located on both sides of the connecting boss (225).

5. The wheel-mounted brake disc according to claim 2, characterized in that: The length direction of the first boss (232) and the second boss (233) both extend radially along the disk body (2). The first boss (232) and the second boss (233) both include a second circumferential ventilation groove (231). The second circumferential ventilation groove (231) passes through the first boss (232) and the second boss (233) respectively along the circumferential direction of the disk body (2).

6. The wheel-mounted brake disc according to claim 5, characterized in that: The outline shape of the first boss (232) and the second boss (233) is an isosceles trapezoid, which includes an axis of symmetry and two hypotenuses. The included angle β between the two hypotenuses of the isosceles trapezoid is ≤4°, and the included angle α between the axis of symmetry of the first boss (232) and the axis of symmetry of the second boss (233) is ≤10°.

7. The wheel-mounted brake disc according to any one of claims 2-6, characterized in that: The wheel-mounted brake disc also includes fasteners, a first heat insulation bushing (3) and a second heat insulation bushing (6). The fastener through hole (211) is a stepped hole. The fastener passes through the fastener through hole (211) of the wheel (1) and the disc body (2) on both sides to fasten the disc body (2) to the wheel (1). The first heat insulation bushing (3) and the second heat insulation bushing (6) are respectively located between the stepped surface of the fastener through hole (211) on both sides and the fastener.

8. A method for manufacturing a high-speed train wheel-mounted brake disc according to any one of claims 1-7, characterized in that, The process includes the following steps: carbon fiber preform preparation step, which involves making non-woven fabric and mesh, and then introducing carbon fiber bundles after cyclically stacking and layering the non-woven fabric and mesh to obtain the carbon fiber preform; The chemical vapor deposition carbon step involves placing the carbon fiber preform into a chemical vapor deposition furnace for chemical vapor deposition carbon treatment to obtain a first low-density carbon preform. In the resin impregnation pyrolysis step, the first low-density carbon-carbon preform is placed in a resin impregnation pyrolysis furnace to obtain a second low-density carbon-carbon preform. In the high-temperature graphitization step, the second low-density carbon-carbon preform is placed in a high-temperature heat treatment furnace for high-temperature graphitization treatment. The machining step involves grinding the second low-density carbon blank after high-temperature graphitization treatment to give it the shape of the wheel-mounted brake disc. In the melt silicon infiltration step, the second low-density carbon-carbon preform after machining is placed in a silicon infiltration furnace for melt silicon infiltration treatment to obtain the wheel brake disc of carbon-ceramic composite material.

9. The preparation method according to claim 8, characterized in that: The density of the carbon fiber preform is 0.4-0.55 g / cm3, the density of the first low-density carbon preform is 0.8-1.0 g / cm3, and the density of the second low-density carbon preform obtained in the resin impregnation and pyrolysis step is 1.3-1.5 g / cm3. The wheel brake disc, manufactured through the melt infiltration step, has a material density of 2.0–2.2 g / cm³, an open porosity of ≤3.5%, a SiC content of 35–50% by mass, a C content of 20–60% by mass, and a Si content of ≤10% by mass. The disc material has a tensile strength ≥100 MPa, a compressive strength ≥300 MPa, a flexural strength ≥160 MPa, an interlaminar shear strength ≥30 MPa, and a thermal conductivity ≥35 W / (m·K).

10. The preparation method according to claim 8, characterized in that: In the carbon fiber preform preparation step, a single layer of non-woven fabric is made using carbon fiber, with fiber orientations of 0° and 90° respectively; the mesh is made using chopped carbon fiber, with a length of 30-100 mm; the non-woven fabric is sequentially layered in the order of 0° non-woven fabric, mesh, 90° non-woven fabric, mesh, and 0° non-woven fabric, with an interlayer density of 10-25 layers / cm in the layering direction; the carbon fiber bundle is introduced in the layering direction with a needle-punching density of 20-30 needles / cm², to obtain a 2.5-dimensional needle-punched carbon fiber preform, wherein the volume ratio of the mesh to the non-woven fabric is in the range of 1:1 to 1:3.

Images