Carbon-ceramic bicycle disc and preparation process

Abstract

The invention provides a carbon-ceramic bicycle disc and a preparation process, the carbon-ceramic bicycle disc is composed of a carbon-ceramic brake friction plate, a high-strength connecting piece and an internal alloy middle lock, and the preparation process of the carbon-ceramic brake friction plate comprises the steps of carbon fiber preform preparation, vapor deposition, rough machining, ceramization and finish machining. The carbon-ceramic bicycle disc provided by the invention has thermal attenuation resistance, can bear high temperature of 1650 DEG C or above, and has no attenuation of braking force during continuous braking; the metal disc has the advantages of high thermal stability, low coefficient of thermal expansion (CTE), difficulty in deformation at high temperature, avoidance of thermal jitter of the metal disc, good wear resistance, good corrosion resistance and ultra-long service life, the wear rate is only 1 / 10 of that of the metal disc, and the service life can reach more than 300,000 kilometers.

Description

Technical Field

[0001] The present invention belongs to the technical field of bicycles and relates to bicycle discs, and in particular to a carbon-ceramic bicycle disc having both the lightweight and high strength properties of carbon fiber and the high temperature resistance and wear resistance of ceramics and a preparation process thereof. Background Art

[0002] Brake pads are a commonly used safety component in mechanical systems, and their main working mode is braking through friction.

[0003] The existing production plan for bicycle brake pads mainly uses metal discs connected with screws and alloy center locks: the metal discs are mostly made of stainless steel or aluminum alloy through stamping, heat treatment and surface anti-rust coating technology to ensure wear resistance and heat dissipation.

[0004] However, traditional stainless steel or aluminum alloy discs are prone to thermal attenuation under high load or humid environments, resulting in insufficient heat dissipation efficiency; the anti-rust coating is prone to wear after long-term use, resulting in performance degradation. Summary of the Invention

[0005] In order to solve the defects of metal discs in existing solutions, the present invention provides a carbon-ceramic bicycle disc and a preparation process, specifically a method for manufacturing a composite structure of carbon fiber reinforced silicon carbide ceramic (carbon-ceramic) brake pads and metal components, belonging to the technical field of high-performance bicycle brake devices.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a process for preparing a carbon-ceramic bicycle disc, the process comprising the following steps:

[0008] 1) Preparation of a carbon fiber preform: mixing long carbon fibers, phenolic resin, and carbon powder, drying the mixture, and curing the mixture to obtain a carbon fiber preform;

[0009] 2) Vapor deposition: The carbon fiber preform obtained in step 1) is fed into a vapor deposition furnace for deposition and densification to obtain a densified rough blank;

[0010] 3) Rough processing: processing the rough blank obtained in step 2) into a disc;

[0011] 4) Ceramics: The disc obtained in step 3) is placed in a siliconizing furnace, silicon powder is added, the temperature is raised to a preset temperature under vacuum, the temperature is maintained, and the temperature is lowered to room temperature under vacuum to obtain a siliconized disc;

[0012] 5) Finishing: The siliconized disc obtained in step 4) is subjected to surface grinding, groove processing, and drilling to obtain a carbon-ceramic friction plate;

[0013] 6) Installation: Connect the carbon-ceramic friction plate obtained in step 5) to the internal alloy center lock through a high-strength connector to obtain a carbon-ceramic bicycle disc.

[0014] As a preferred embodiment of the present invention, in step 1), the mass ratio of the long carbon fibers, the phenolic resin, and the carbon powder is 1:0.4-0.6:0.3-0.5.

[0015] As a preferred embodiment of the present invention, in step 1), the mixture is dried on a press, maintaining the upper platen temperature at 120-140°C and the lower platen temperature at 100-110°C, keeping warm for 1 hour, then pressurizing to 8-12 MPa, keeping warm for 10 minutes, and then pressurizing to 18-20 MPa, and keeping warm for 30 minutes.

[0016] As a preferred embodiment of the present invention, in step 1), the curing method of the dried mixture is as follows: at 20-25Mpa, the temperature of the upper pressing plate is raised to 180-200°C, the temperature of the lower pressing plate is raised to 120-150°C, the pressure is released once after 1 minute, and the pressure is increased to 20-25Mpa again, and the mixture is kept warm for 1 hour. The temperature of the lower pressing plate is adjusted to 180-200°C and kept warm for 4 hours; after 4 hours, the mixture is cooled to 80-100°C, the pressure is released, and the mixture is cooled to room temperature to obtain a carbon fiber preform.

[0017] As a preferred embodiment of the present invention, in step 2), the temperature of vapor deposition is 1000-1100°C, the precursor gas introduced into the vapor deposition is CH4 or C3H8, and an inert gas is introduced indirectly, and the set temperature, vacuum and continuous introduction of methane are maintained for 250 hours.

[0018] As a preferred embodiment of the present invention, in step 4), the temperature is raised to 1000°C at a rate of 50°C / h, then raised to 1700-1800°C at a rate of 30°C / h, and the holding time is 1.5-2.5h.

[0019] As a preferred embodiment of the present invention, in step 5), the flatness of the carbon-ceramic bicycle disc is ≤0.05 mm.

[0020] As a preferred embodiment of the present invention, the density of the carbon fiber preform is ≥1.6 g / cm 3 .

[0021] In a second aspect, the present invention also provides a carbon-ceramic bicycle disc produced by the above-mentioned preparation process.

[0022] As a preferred solution of the present invention, the carbon-ceramic bicycle disc is composed of a carbon-ceramic brake friction plate, a high-strength connector and an internal alloy center lock.

[0023] Preferably, the high-strength connecting members include high-strength screws, rivets, or other fasteners that can perform a fastening function.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1) The carbon-ceramic bicycle disc provided by the present invention has resistance to thermal decay and can withstand temperatures above 1650°C. During continuous braking, the braking force does not decay. It also has high thermal stability and a low coefficient of thermal expansion (CTE). It is not easy to deform at high temperatures, avoiding the "thermal jitter" problem of metal discs.

[0026] 2) The carbon-ceramic bicycle disc of the present invention has good wear resistance and corrosion resistance, and has an ultra-long service life. The wear rate is only 1 / 10 of that of a metal disc, and the service life can reach more than 300,000 kilometers.

[0027] 3) The carbon-ceramic bicycle disc of the present invention has a stable friction coefficient of 0.4-0.5, provides more linear and immediate braking force, does not require rust removal and deformation correction, does not contain heavy metals, and the carbon fiber and ceramic matrix can be separated and recycled, which is more energy-efficient than metal smelting and is recyclable.

[0028] 4) The carbon-ceramic bicycle disc of this invention, with its core advantages of high-temperature resistance and long life, completely overcomes the pain points of metal discs and is the ultimate solution for high-performance braking systems. With large-scale production, its cost will further decrease, gradually becoming popular in the civilian market. DETAILED DESCRIPTION

[0029] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0030] The present invention provides a process for preparing a carbon-ceramic bicycle disc. The carbon-ceramic disc comprises three parts: a carbon-ceramic brake friction pad, a high-strength connector, and an internal alloy center lock. The preparation process of the carbon-ceramic brake friction pad is as follows: carbon fiber preform - vapor deposition - rough processing - ceramicization - fine processing.

[0031] The preparation process comprises the following steps:

[0032] 1) Preparation of a carbon fiber preform: mixing long carbon fibers, phenolic resin, and carbon powder, drying the mixture, and curing the mixture to obtain a carbon fiber preform;

[0033] 2) Vapor deposition: The carbon fiber preform obtained in step 1) is fed into a vapor deposition furnace for deposition and densification to obtain a densified rough blank;

[0034] 3) Rough processing: processing the rough blank obtained in step 2) into a disc;

[0035] 4) Ceramics: The disc obtained in step 3) is placed in a siliconizing furnace, silicon powder is added, the temperature is raised to a preset temperature under vacuum, the temperature is maintained, and the temperature is lowered to room temperature under vacuum to obtain a siliconized disc;

[0036] 5) Finishing: The siliconized disc obtained in step 4) is subjected to surface grinding, groove processing, and drilling to obtain a carbon-ceramic friction plate;

[0037] 6) Installation: Connect the carbon-ceramic friction plate obtained in step 5) to the internal alloy center lock through a high-strength connector to obtain a carbon-ceramic bicycle disc.

[0038] Example 1

[0039] This embodiment provides a process for preparing a carbon-ceramic bicycle disc, comprising:

[0040] 1) Preparation of a carbon fiber preform: Long carbon fibers, phenolic resin, and carbon powder are mixed in a ratio of 1:0.5:0.3 and loaded on a press to prepare a carbon fiber preform.

[0041] Put the mixed material on the press for drying: keep the upper platen temperature at 120℃ and the lower platen temperature at 110℃, keep warm for 1 hour, then increase the pressure to 12Mpa, keep warm for 10 minutes, then increase the pressure to 20Mpa, and keep warm for 30 minutes.

[0042] The dried material begins to solidify: heating and pressurizing to 20Mpa, raising the upper platen temperature to 200°C and the lower platen temperature to 150°C. After 1 minute, the pressure is released once, and the pressure is increased to 25Mpa, kept warm for 1 hour, and the lower platen is adjusted to 200°C and kept warm for 4 hours. After 4 hours, the temperature is lowered to 100°C, and the pressure is released. The solidified product is cooled to room temperature and can be taken out of the oven. The rough blank is prepared.

[0043] 2) Vapor deposition (CVD): The pressed rough blank is loaded into a vapor deposition furnace for deposition and densification. The process parameters of the vapor deposition furnace can be set to maintain 1050°C for the first 50 hours, increase to 1100°C for the middle 100 hours, and drop to 1080°C for the last 50 hours. The pressure in the furnace is kept in a vacuum state. The precursor gas for vapor deposition is carbon source gas such as CH4 and C3H8. At the same time, inert gases such as hydrogen and nitrogen are indirectly introduced. The temperature, pressure and continuous gas introduction are maintained for 250 hours. After 250 hours, the temperature begins to drop, the equipment stops heating, the furnace remains in a vacuum state, the carbon source gas stops being introduced, and inert gas can be continuously introduced to help cool down and shorten the cooling time. After the temperature in the furnace drops to room temperature, the furnace can be opened to take out the densified rough blank.

[0044] 3) Rough machining: Cut into near-final size (leave 0.6mm margin) according to the drawing, drill holes, and machine the rough blank into the shape and approximate size of the disc.

[0045] 4) Ceramicization: Place the roughly processed disc in a high-temperature siliconizing furnace and add silicon powder. First, raise the temperature from room temperature to 1000℃ at a rate of 50℃ / h under vacuum, and then raise the temperature to 1750℃ at a rate of 30℃ / h (reaction: Si+C→SiC). Keep it at 1750℃ for about 2h, then start cooling after 2h. Cool it down to room temperature under continuous vacuum, open the furnace and take out the siliconized disc.

[0046] 5) Finishing:

[0047] Through the processes of surface grinding (flatness ≤ 0.05mm), groove processing (to improve the friction coefficient), and drilling (tolerance ± 0.02mm), the siliconized disc is processed into a finished carbon ceramic friction plate.

[0048] 6) Assembly: Use high-strength connectors to pass through the mounting holes on the carbon ceramic friction plate and connect to the internal alloy center lock.

[0049] Example 2

[0050] This embodiment provides a process for preparing a carbon-ceramic bicycle disc, comprising:

[0051] 1) Preparation of carbon fiber preform: Long carbon fiber, phenolic resin and carbon powder are mixed in a ratio of 1:0.5:0.5 and loaded on a press to prepare a carbon fiber preform.

[0052] Put the mixed material on the press for drying: keep the upper platen temperature at 120℃ and the lower platen temperature at 100℃, keep warm for 1 hour, then increase the pressure to 12Mpa, keep warm for 10 minutes, then increase the pressure to 20Mpa, and keep warm for 30 minutes.

[0053] The dried material begins to solidify: heating and pressurizing to 20Mpa, raising the upper platen temperature to 200°C and the lower platen temperature to 150°C. After 1 minute, the pressure is released once, and the pressure is increased to 25Mpa, kept warm for 1 hour, and the lower platen is adjusted to 200°C and kept warm for 4 hours. After 4 hours, the temperature is lowered to 100°C, and the pressure is released. The solidified product is cooled to room temperature and can be taken out of the oven. The rough blank is prepared.

[0054] 2) Vapor deposition (CVD): The pressed rough blank is loaded into a vapor deposition furnace for deposition and densification. The process parameters of the vapor deposition furnace can be set to maintain 1050°C for the first 50 hours, increase to 1100°C for the middle 100 hours, and drop to 1080°C for the last 50 hours. The pressure in the furnace is kept in a vacuum state. The precursor gas for vapor deposition is carbon source gas such as CH4 and C3H8. At the same time, inert gases such as hydrogen and nitrogen are indirectly introduced. The temperature, pressure and continuous gas introduction are maintained for 250 hours. After 250 hours, the temperature begins to drop, the equipment stops heating, the furnace remains in a vacuum state, the carbon source gas stops being introduced, and inert gas can be continuously introduced to help cool down and shorten the cooling time. After the temperature in the furnace drops to room temperature, the furnace can be opened to take out the densified rough blank.

[0055] 3) Rough machining: according to the drawing, cut into near-final size (leave 0.5mm margin), drill holes, and process the rough blank into the shape and approximate size of the disc.

[0056] 4) Ceramicization: Place the roughly processed disc in a high-temperature siliconizing furnace and add silicon powder. First, raise the temperature from room temperature to 1000℃ at a rate of 50℃ / h under vacuum, and then raise the temperature to 1750℃ at a rate of 30℃ / h (reaction: Si+C→SiC). Keep it at 1750℃ for about 2h, then start cooling after 2h. Cool it down to room temperature under continuous vacuum, open the furnace and take out the siliconized disc.

[0057] 5) Finishing: Through surface grinding (flatness ≤ 0.05mm), groove processing (to improve the friction coefficient), and drilling (tolerance ± 0.02mm), the siliconized disc is processed into a finished carbon ceramic friction plate.

[0058] 6) Assembly: Use high-strength connectors to pass through the disc mounting holes and connect to the internal alloy center lock.

[0059] Comparative example: the friction plate adopts a metal disc.

[0060] The carbon-ceramic bicycle discs obtained in Examples 1 and 2 and the metal disc of the comparative example were subjected to performance tests, including friction coefficient, braking response, thermal decay resistance, wear rate, corrosion resistance, and deformation resistance. The results are shown in Table 1.

[0061] Table 1. Performance test results

[0062]

[0063] It can be seen that the present invention replaces traditional metal (such as stainless steel, aluminum alloy) brake discs with carbon-ceramic (carbon fiber reinforced ceramic) composite materials, which has the following advantages:

[0064] 1. Anti-thermal attenuation performance:

[0065] High temperature resistance: Carbon ceramic can withstand temperatures above 1650°C, and the braking force does not decay during continuous braking.

[0066] 2. Thermal stability: The coefficient of thermal expansion (CTE) is low, making it less likely to deform at high temperatures, thus avoiding the "thermal jitter" problem of metal discs.

[0067] 3.Extremely long service life:

[0068] Wear resistance: The wear rate is only 1 / 10 of that of metal discs, and the service life can reach more than 300,000 kilometers (metal discs usually need to be replaced after 20,000-30,000 kilometers).

[0069] Corrosion resistance: completely rust-proof, resistant to salt spray, acid and alkali corrosion, suitable for humid or harsh environments (such as rainy and snowy weather, coastal areas).

[0070] 4. Braking performance optimization:

[0071] Friction coefficient: When carbon ceramic is combined with special brake pads, the friction coefficient is stable at 0.4-0.5, providing more linear and immediate braking force.

[0072] Wet performance: No need to preheat on rainy days, and the brake response is faster (water film on the metal surface can easily cause slipping).

[0073] 5. Reduced maintenance costs:

[0074] Maintenance-free: No need to remove rust or correct deformation (metal discs are prone to warping at high temperatures).

[0075] Extended brake pad life: Carbon ceramic causes less wear on brake pads, and the life of the matching brake pads is increased by 50%.

[0076] 6. Environmental protection and sustainability:

[0077] Pollution-free materials: do not contain heavy metals. Although the manufacturing process is energy-intensive, the long lifespan offsets carbon emissions (frequent replacement of metal discs increases resource consumption).

[0078] Recyclability: Carbon fiber and ceramic matrix can be separated and recycled, which is more energy-efficient than metal smelting.

[0079] The carbon-ceramic disc of the present invention completely solves the pain points of metal discs through core advantages such as high temperature resistance and long life, and is the ultimate solution for high-performance braking systems.

[0080] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form or substance. It should be pointed out that ordinary technicians in this technical field can make several improvements and supplements without departing from the method of the present invention. These improvements and supplements should also be regarded as the scope of protection of the present invention. Any equivalent changes, modifications and evolutions made by technicians familiar with this profession without departing from the spirit and scope of the present invention by using the technical content disclosed above are all equivalent embodiments of the present invention; at the same time, any equivalent changes, modifications and evolutions made to the above embodiments based on the essential technology of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A process for preparing a carbon ceramic bicycle disc, characterized in that: The preparation process comprises the following steps: 1) Preparation of a carbon fiber preform: mixing long carbon fibers, phenolic resin, and carbon powder, drying the mixture, and curing the mixture to obtain a carbon fiber preform; 2) Vapor deposition: The carbon fiber preform obtained in step 1) is fed into a vapor deposition furnace for deposition and densification to obtain a densified rough blank; 3) Rough processing: processing the rough blank obtained in step 2) into a disc; 4) Ceramics: The disc obtained in step 3) is placed in a siliconizing furnace, silicon powder is added, the temperature is raised to a preset temperature under vacuum, the temperature is maintained, and the temperature is lowered to room temperature under vacuum to obtain a siliconized disc; 5) Finishing: The siliconized disc obtained in step 4) is subjected to surface grinding, groove processing, and drilling to obtain a carbon-ceramic friction plate; 6) Installation: Connect the carbon-ceramic friction plate obtained in step 5) to the internal alloy center lock through a high-strength connector to obtain a carbon-ceramic bicycle disc.

2. The process for preparing a carbon ceramic bicycle disc according to claim 1, characterized in that: In step 1), the mass ratio of the long carbon fiber, the phenolic resin and the carbon powder is 1:0.4-0.6:0.3-0.

5.

3. The process for preparing a carbon ceramic bicycle disc according to claim 1, characterized in that: In step 1), the mixture is dried on a press, maintaining the upper platen temperature at 120-140°C and the lower platen temperature at 100-110°C for 1 hour, then pressurizing to 8-12 MPa, maintaining for 10 minutes, and then pressurizing to 18-20 MPa, maintaining for 30 minutes.

4. The process for preparing a carbon ceramic bicycle disc according to claim 1, characterized in that: In step 1), the curing method of the dried mixture is as follows: at 20-25Mpa, the temperature of the upper press plate is raised to 180-200°C, the temperature of the lower press plate is raised to 120-150°C, the pressure is released once after 1 minute, and the pressure is increased to 20-25Mpa again, and the mixture is kept warm for 1 hour. The temperature of the lower press plate is adjusted to 180-200°C and kept warm for 4 hours; after 4 hours, the mixture is cooled to 80-100°C, the pressure is released, and the mixture is cooled to room temperature to obtain a carbon fiber preform.

5. The process for preparing a carbon ceramic bicycle disc according to claim 1, characterized in that: In step 2), the temperature of vapor deposition is 1000-1100°C, the precursor gas introduced into the vapor deposition is CH4 or C3H8, and an inert gas is introduced indirectly, and the set temperature, vacuum and continuous introduction of methane are maintained for 250 hours.

6. The process for preparing a carbon ceramic bicycle disc according to claim 1, characterized in that: In step 4), the temperature is raised to 1000° C. at a rate of 50° C. / h, then raised to 1700-1800° C. at a rate of 30° C. / h, and the holding time is 1.5-2.5 h.

7. The process for preparing a carbon ceramic bicycle disc according to claim 1, characterized in that: In step 5), the flatness of the carbon-ceramic bicycle disc is ≤0.05 mm.

8. A process for preparing a carbon-ceramic bicycle disc according to any one of claims 1 to 7, characterized in that: The density of the carbon fiber preform is ≥1.6g / cm 3 .

9. A carbon ceramic bicycle disc, characterized in that: The carbon-ceramic bicycle disc is prepared by the preparation process described in any one of claims 1 to 8.

10. The carbon-ceramic bicycle disc according to claim 9, characterized in that: The carbon-ceramic bicycle disc is composed of a carbon-ceramic brake friction plate, a high-strength connecting piece and an internal alloy center lock. The high-strength connecting piece includes a high-strength screw or a rivet.

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