Combined carbon-ceramic brake disc without connecting piece and preparation method of combined carbon-ceramic brake disc

Abstract

The invention relates to a connector-free combined carbon ceramic brake disc which comprises a first friction panel and a second friction panel, the first friction panel and the second friction panel are connected through a plurality of cushion blocks in an annular array, and concave-convex structures used for mutual connection are arranged on the first friction panel, the second friction panel and the cushion blocks. The invention further provides a preparation method of the brake disc, reaction bonding layers are formed in gaps between the upper friction face and the cushion block and between the lower friction face and the cushion block through a reaction melt permeation technology, and combined connection of the combined carbon-ceramic brake disc is achieved. When the brake disc works, the concave-convex structures among the first friction panel, the second friction panel and the cushion block bear the shearing effect, ceramic phases of the concave-convex structures and gaps of the concave-convex structures serve as main bearing units for resisting shearing acting force, the anti-shearing capacity is high, and combined connection of the combined carbon-ceramic brake disc without connecting pieces is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of carbon fiber toughened ceramic matrix composite brake discs, and in particular to a connector-free combined carbon-ceramic brake disc and a preparation method thereof. Background Art

[0002] Continuous Fiber Reinforced Ceramic Matrix Composites (CFCC) inherits the excellent properties of ceramics such as low density, high strength, and oxidation resistance, and overcomes the weaknesses of ceramics such as high brittleness and poor reliability. It exhibits fracture behavior similar to that of metals, is insensitive to cracks, and is not prone to catastrophic fracture. It has great application potential in the field of friction braking. C / SiC composites have a series of excellent properties such as high specific strength, high specific modulus, high hardness, low density, and low thermal and wet decay of friction coefficient. It is one of the most promising friction materials at present.

[0003] The preparation process of C / SiC composites can be divided into: gas phase route, also known as chemical vapor infiltration (CVI); liquid phase route, including polymer impregnation pyrolysis (PIP) and liquid silicon infiltration (LSI) or reactive melt infiltration (RMI). The RMI process is a densification process that generates a matrix in situ through a chemical reaction. The reaction products are usually carbides and borides. The principle is to introduce carbides and borides by reacting a high-temperature molten metal element or alloy mixture with a porous material containing carbon or boron. In the RMI process, no additional mechanical pressure is required. The molten metal or alloy spontaneously infiltrates into the preform under the action of capillary force, and reacts with carbon or the introduced precursor to form a ceramic matrix.

[0004] Compared with chopped fiber reinforced ceramic matrix composites, continuous carbon fiber reinforced ceramic matrix composites have advantages in material body strength and are often used to manufacture high-performance sports cars, aircraft and other vehicle brake discs. To meet the braking requirements, the brake disc needs to have a certain thickness and diameter, and the thickness is generally 25~40mm. Traditional integral carbon ceramic brake discs use carbon fiber needle punched preforms and mechanical processing to ensure the appearance of the product, which has many shortcomings and difficulties: 1. The processing of ventilation grooves of integral carbon ceramic brake discs is labor-intensive and material-intensive. The integral carbon ceramic disc will have multiple ventilation grooves arranged around the circumference to reduce weight and dissipate heat. However, since the density of the brake disc blank is low, the ventilation grooves cannot be processed. The ventilation grooves can only be processed when the brake disc blank has a certain strength and processability. In addition, the processing of the ventilation grooves is time-consuming, and the removed materials are all scraps, resulting in a large waste of manpower, materials and time; 2. The thickness of the integral carbon-ceramic brake disc is relatively thick, and the RMI high-temperature modification has uneven density. Since the thickness of the integral carbon-ceramic brake disc is relatively thick, generally 25~42mm, and there are different structures in the thickness direction of the carbon-ceramic brake disc, such as the mounting hole step and ventilation slot, the melt penetration process is complicated and difficult to control, resulting in uneven density of the carbon-ceramic brake disc blank after RMI modification, which will directly lead to excessive residual imbalance of the carbon-ceramic brake disc and product scrapping.

[0005] In order to overcome the process disadvantages of the above-mentioned integral carbon-ceramic brake disc, a combined carbon-ceramic brake disc has been developed in the prior art. The combined carbon-ceramic brake disc is divided into two halves in the thickness direction, and the circumferential processing of the ventilation groove is changed to the milling processing in the plane of the single-side brake disc, which greatly shortens the processing time and reduces the processing difficulty; after processing, the two halves of the brake disc are riveted or screwed into a whole by mechanical connectors such as rivets and screws. Therefore, during the use of the combined carbon-ceramic brake disc, when the two halves of the brake disc generate a torsional load of relative rotation, the mechanical connector is the main load-bearing unit, and its shear strength directly determines the mechanical properties of the brake disc. However, due to the limited installation area on the brake disc, the diameter, number and arrangement of the mechanical connector are all limited. During use, once a rivet is damaged, the overall performance of the brake disc will be greatly reduced. Summary of the invention

[0006] The purpose of the present invention is to avoid the shortcomings of the prior art and provide a connector-free combined carbon-ceramic brake disc and a preparation method thereof, so as to solve the problems of labor-consuming and material-consuming processing of ventilation grooves of integral carbon-ceramic brake discs and poor reliability of rivet connections of traditional combined carbon-ceramic brake discs.

[0007] To achieve the above object, the technical solution adopted by the present invention is: A connector-free combined carbon-ceramic brake disc comprises a first friction panel and a second friction panel, wherein the first friction panel and the second friction panel are connected via a plurality of pads in an annular array, wherein the first friction panel, the second friction panel and the pads are provided with concave-convex structures for mutual connection; and a central hole for mounting a joint is provided in the middle of the second friction panel.

[0008] Furthermore, the concave-convex structure includes bosses on the surfaces of the pad block that are opposite to the first friction panel and the second friction panel, and grooves that match the bosses are provided on the first friction panel and the second friction panel.

[0009] Furthermore, the concave-convex structure includes grooves on the surfaces of the pad that are opposite to the first friction panel and the second friction panel, and bosses that match the grooves are provided on the first friction panel and the second friction panel.

[0010] Furthermore, the concave-convex structure includes a boss provided on the surface opposite to the pad and the first friction panel, a groove provided on the surface opposite to the pad and the second friction panel, and the first friction panel and the second friction panel are respectively provided with a groove corresponding to the boss on the pad and a boss corresponding to the groove on the pad.

[0011] Furthermore, the second friction panel is provided with a mounting hole for connecting bolts; and the cushion block is provided with a bolt hole corresponding to the mounting hole near the center of the circle.

[0012] Furthermore, the brake disc has a thickness of 18-48 mm and an outer diameter of 180-460 mm.

[0013] Furthermore, the pads are evenly distributed along the circumferential direction of the brake disc, the number of the pads is 3 to 24, and the thickness is 1 / 6 to 1 / 2 of the thickness of the brake disc.

[0014] The present invention also provides a method for preparing a connector-free combined carbon-ceramic brake disc, comprising the following steps: S1: preparing friction surface blank and pad blank by using carbon / carbon material; S2: machining the first friction panel, the second friction panel and the pad; S3: With the help of the assembly tool, the pads are embedded in the second friction panel, the pads are placed in a diagonal order, and the pads are fixed to the second friction panel with 502 glue; S4: Remove the assembly tool, embed the first friction panel into the pad, and fix it with 502 glue, then clamp the assembly with a C-shaped steel clamp, and after the glue is dry, remove the C-shaped steel clamp to obtain a carbon / carbon material brake disc preform; S5: treating the carbon / carbon material brake disc preform with a reaction melt infiltration process to densify it into a carbon-ceramic material brake disc, and infiltrating the assembly gap of the concave-convex structure with liquid silicon to react and generate a ceramic bonding layer, thereby realizing the connection of the carbon-ceramic brake disc; S6: Perform size finishing on the carbon-ceramic brake disc to obtain a carbon-ceramic brake disc product.

[0015] Furthermore, in S1, the density of the carbon / carbon material is 1.0-2.0 g / cm 3 ; In S5, the density of carbon ceramic material is 1.8~2.6g / cm 3 .

[0016] Furthermore, S5 includes: S501: placing a carbon / carbon material brake disc preform into a graphite crucible, adding silicon powder into the crucible, and then placing the crucible into a vacuum induction furnace; the silicon powder has a purity of 98-99.9% and a mesh size of 60-500; S502: Start the vacuum pump to evacuate the interior of the vacuum induction furnace. When the vacuum degree inside the furnace is ≤200Pa, start heating the furnace from room temperature to 1600±50℃ at a rate of 5~20℃ / min, and keep it at this temperature for 0.5-3h. After keeping it warm, lower the interior temperature of the furnace to room temperature, take out the graphite crucible, and obtain a combined carbon-ceramic brake disc.

[0017] The beneficial effects of the present invention are: 1. The present invention designs a composite carbon-ceramic brake disc structure without connectors. During the product preparation process, the brake surfaces and pads on both sides are processed separately, and a ventilation groove structure is naturally formed in the circumferential direction of the brake disc after being combined, thereby solving the problem that the ventilation grooves of the traditional integral carbon-ceramic brake disc are time-consuming, labor-intensive, and material-intensive to process; 2. The present invention disassembles the traditional thick integral carbon-ceramic brake disc into multiple parts, which not only improves the material utilization rate of the preform flat plate, and each part can be prepared separately in large quantities, but also reduces the process difficulty of the preparation process due to the thickness of the preform, the uneven matrix carbon density, the uneven density of the ceramic phase after high-temperature modification, etc., and the quality of each pad can be screened before assembly, and the quality fluctuation range of the pad can be controlled to ensure that each pad has good quality consistency before assembly, thereby improving the uniformity of the finished carbon-ceramic brake disc, and then improving the dynamic balance performance of the finished carbon-ceramic brake disc, effectively reducing the problem of excessive dynamic imbalance caused by overweight of the finished carbon-ceramic brake disc, reducing the processing amount of dynamic balancing and deweighting, saving material and processing costs, shortening the preparation cycle, and improving the first-time qualified rate of the product.

[0018] 3. The present invention changes the connection mode of the combined carbon-ceramic disc from rivet riveting to a concave-convex structure, changes the force form of the connection unit from the shear of the rivet with a smaller cross-section to the shear resistance of the concave-convex structure with a larger cross-section, and forms a connection layer through RMI reaction at the junction of the concave-convex structure, giving full play to the advantage of the good compressive performance of the ceramic phase, and realizing a reliable combination of a combined carbon-ceramic brake disc without connecting parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the structure of a connector-free combined carbon-ceramic brake disc of the present invention; Figure 2 This is a structural exploded view of a connector-free combined carbon-ceramic brake disc of the present invention; Figure 3 is a cross-sectional view of the concave-convex structure in Example 1; Figure 4 is a cross-sectional view of the concave-convex structure in Example 2; Figure 5 is a cross-sectional view of the concave-convex structure in Example 3; Figure 6 This is a photo of clamping a combined carbon-ceramic brake disc without connectors of the present invention; Figure 7 This is a rear top view of a connector-free combined carbon-ceramic brake disc RMI of the present invention; Figure 8 This is a partial photo of the rear joint of a joint-free combined carbon-ceramic brake disc RMI of the present invention; Fig. 9 This is a photo of a joint-free combined carbon-ceramic brake disc product of the present invention before road testing (with the first friction panel facing upward); Fig.10 This is a photo of a connector-free combined carbon-ceramic brake disc product of the present invention after road testing (the first friction panel is facing upward).

[0020] Fig.11 This is a photo of a connector-free combined carbon-ceramic brake disc product of the present invention after road testing (the second friction panel is facing upward).

[0021] In the figure: 1, first friction panel; 2, second friction panel; 21, mounting hole; 3, cushion block; 31, bolt hole 4, concave-convex structure; 5, assembly gap. DETAILED DESCRIPTION

[0022] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0023] Example 1: Figure 1-3 As shown, a connector-free combined carbon-ceramic brake disc comprises a first friction panel 1 and a second friction panel 2, wherein the first friction panel 1 and the second friction panel 2 are connected via a plurality of annular array pads 3, and the first friction panel 1, the second friction panel 2 and the pads 3 are provided with a concave-convex structure 4 for mutual connection; a central hole for mounting a joint is provided in the middle of the second friction panel 2.

[0024] The concave-convex structure 4 includes bosses on the surfaces of the pad 3 facing the first friction panel 1 and the second friction panel 2, and grooves matching the bosses are provided on the first friction panel 1 and the second friction panel 2.

[0025] The second friction panel 2 is provided with a mounting hole 21 for connecting bolts; the cushion block 3 is provided with a bolt hole 31 corresponding to the mounting hole 21 close to the center of the circle.

[0026] The brake disc has a thickness of 18-48 mm and an outer diameter of 180-460 mm.

[0027] The pads 3 are evenly distributed along the circumferential direction of the brake disc, the number of the pads 3 is 3 to 24, and the thickness is 1 / 6 to 1 / 2 of the thickness of the brake disc.

[0028] Example 2: See Figure 1 , Figure 2 , Figure 4 As shown, it is the same as Example 1, except that: the concave-convex structure 4 includes grooves on the surfaces of the pad 3 opposite to the first friction panel 1 and the second friction panel 2, and the first friction panel 1 and the second friction panel 2 are provided with bosses that match the grooves.

[0029] Embodiment 3: Same as Embodiment 1, except that: the concave-convex structure 4 includes a boss provided on the surface opposite to the pad 3 and the first friction panel 1, a groove provided on the surface opposite to the pad 3 and the second friction panel 2, and the first friction panel 1 and the second friction panel 2 are respectively provided with a groove corresponding to the boss on the pad 3 and a boss corresponding to the groove on the pad 3.

[0030] Example 4: Figure 6-11 As shown, a method for preparing a connector-free combined carbon-ceramic brake disc comprises the following steps: S1: Use carbon / carbon material to prepare friction surface blanks and pad blanks, and the density of carbon / carbon material is 1.0~2.0g / cm 3 ; S2: machining the first friction panel 1, the second friction panel 2 and the pad 3; S3: With the assistance of the assembly tool, the pad 3 is embedded in the second friction panel 2, the pads 3 are placed in a diagonal order, and the pads 3 are fixed to the second friction panel 2 with 502 glue; S4: Remove the assembly tool, embed the first friction panel 1 into the pad 3, and fix it with 502 glue, then clamp the assembly with a C-shaped steel clamp, and after the glue is dry, remove the C-shaped steel clamp to obtain a carbon / carbon material brake disc preform; S5: The carbon / carbon material brake disc preform is subjected to a reactive melt infiltration process to densify it into a carbon ceramic material brake disc, and the density of the carbon ceramic material is 1.8~2.6g / cm 3 ; Liquid silicon is infiltrated into the assembly gap 5 of the concave-convex structure 4 to react and generate a ceramic bonding layer, thereby achieving the connection of the carbon-ceramic brake disc; Specifically: S501: placing a carbon / carbon material brake disc preform into a graphite crucible, adding silicon powder into the crucible, and then placing the crucible into a vacuum induction furnace; the silicon powder has a purity of 98-99.9% and a mesh size of 60-500; S502: Start the vacuum pump to evacuate the interior of the vacuum induction furnace. When the vacuum degree inside the furnace is ≤200Pa, start heating the furnace from room temperature to 1600±50℃ at a rate of 5~20℃ / min, and keep it at this temperature for 0.5-3h. After keeping it warm, lower the interior temperature of the furnace to room temperature, take out the graphite crucible, and obtain a combined carbon-ceramic brake disc.

[0031] S6: Perform size finishing on the carbon-ceramic brake disc to obtain a carbon-ceramic brake disc product.

[0032] The actual picture of the assembled carbon / carbon material brake disc preform is as follows Figure 6 The actual picture of the carbon ceramic brake disc after RMI is shown in Figure 7 , 8 As shown, the assembly gap is filled with ceramics generated by the RMI process reaction, so that the carbon-ceramic brake disc forms an integral body, thereby realizing a reliable connection of the combined carbon-ceramic brake disc without connectors.

[0033] Fig. 9 This is a photo of the jointless combined carbon ceramic brake disc product before road testing. Fig.10 , 11 These are photos of the connector-free combined carbon-ceramic brake disc product after road testing, indicating that the connector-free combined carbon-ceramic brake disc product has a reliable connection before and after the test, a complete structure, and meets the use requirements.

[0034] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A connector-free combined carbon-ceramic brake disc, characterized in that: The invention comprises a first friction panel (1) and a second friction panel (2), wherein the first friction panel (1) and the second friction panel (2) are connected via a plurality of pads (3) in an annular array, and the first friction panel (1), the second friction panel (2) and the pads (3) are provided with concave-convex structures (4) for mutual connection; and a central hole for mounting a joint is provided in the middle of the second friction panel (2).

2. The connector-free combined carbon-ceramic brake disc according to claim 1, characterized in that: The concave-convex structure (4) comprises bosses provided on the surfaces of the pad (3) opposite to the first friction panel (1) and the second friction panel (2), and grooves matching the bosses are provided on the first friction panel (1) and the second friction panel (2).

3. The connector-free combined carbon-ceramic brake disc according to claim 1, characterized in that: The concave-convex structure (4) comprises concave grooves on the surfaces of the pad (3) opposite to the first friction panel (1) and the second friction panel (2), and bosses matching the concave grooves are provided on the first friction panel (1) and the second friction panel (2).

4. The connector-free combined carbon-ceramic brake disc according to claim 1, characterized in that: The concave-convex structure (4) comprises a boss provided on the surface of the pad (3) opposite to the first friction panel (1), a groove provided on the surface of the pad (3) opposite to the second friction panel (2), and the first friction panel (1) and the second friction panel (2) are respectively provided with a groove corresponding to the boss on the pad (3) and a boss corresponding to the groove on the pad (3).

5. The connector-free combined carbon-ceramic brake disc according to claim 1, characterized in that: The second friction panel (2) is provided with a mounting hole (21) for connecting a bolt; and the cushion block (3) is provided with a bolt hole (31) corresponding to the mounting hole (21) in a direction close to the center of the circle.

6. The connector-free combined carbon-ceramic brake disc according to claim 1, characterized in that: The brake disc has a thickness of 18-48 mm and an outer diameter of 180-460 mm.

7. The connector-free combined carbon-ceramic brake disc according to any one of claims 1 to 6, characterized in that: The pads (3) are evenly distributed along the circumferential direction of the brake disc, the number of the pads (3) is 3 to 24, and the thickness is 1 / 6 to 1 / 2 of the thickness of the brake disc.

8. The method for preparing the connector-free combined carbon-ceramic brake disc according to claims 1 to 7, characterized in that: The following steps are involved: S1: preparing friction surface blank and pad blank by using carbon / carbon material; S2: Mechanically processing the first friction panel (1), the second friction panel (2) and the pad (3); S3: With the assistance of an assembly tool, the pad (3) is embedded in the second friction panel (2), the pads (3) are placed in a diagonal order, and the pads (3) are fixed to the second friction panel (2) with 502 glue; S4: removing the assembly tool, embedding the first friction panel (1) into the pad (3), and fixing it with 502 glue, and then clamping the assembly with a C-shaped steel clamp. After the glue is dry, remove the C-shaped steel clamp to obtain a carbon / carbon material brake disc preform; S5: treating the carbon / carbon material brake disc preform with a reaction melt infiltration process to densify it into a carbon-ceramic brake disc, and infiltrating the assembly gap (5) of the concave-convex structure (4) with liquid silicon to react and generate a ceramic bonding layer, thereby achieving the connection of the carbon-ceramic brake disc; S6: Perform size finishing on the carbon-ceramic brake disc to obtain a carbon-ceramic brake disc product.

9. The method for preparing the connector-free combined carbon-ceramic brake disc according to claim 8, characterized in that: In S1, the density of carbon / carbon material is 1.0~2.0g / cm 3 ; In S5, the density of carbon ceramic material is 1.8~2.6g / cm 3 .

10. The method for preparing a joint-free combined carbon-ceramic brake disc according to claim 8, characterized in that S5 include: S501: placing a carbon / carbon material brake disc preform into a graphite crucible, adding silicon powder into the crucible, and then placing the crucible into a vacuum induction furnace; the silicon powder has a purity of 98-99.9% and a mesh size of 60-500; S502: Start the vacuum pump to evacuate the interior of the vacuum induction furnace. When the vacuum degree inside the furnace is ≤200Pa, start heating the furnace from room temperature to 1600±50℃ at a rate of 5~20℃ / min, and keep it at this temperature for 0.5-3h. After keeping it warm, lower the interior temperature of the furnace to room temperature, take out the graphite crucible, and obtain a combined carbon-ceramic brake disc.

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