Composite material brake pad for rail vehicle and forming method thereof

Abstract

The present invention relates to the technical field of rail transit vehicles, and specifically provides a composite brake pad for rail vehicles and a molding method thereof, wherein the brake pad comprises a wearing layer, a brake pad backing plate, and a composite material T-shaped reinforcement nail; the molding method of the brake pad backing plate comprises the following steps: S1, preparing a 3K carbon cloth / barium phenolic prepreg; S2, preparing a composite material T-shaped reinforcement nail and pre-installing it on a molding die; S3, laying the 3K carbon cloth / barium phenolic prepreg on the molding die to form a wearing layer; S4, preparing a high-silica cloth / barium phenolic prepreg; S5, laying the high-silica cloth / barium phenolic prepreg on top of the wearing layer to form a brake pad backing plate; S6, implanting the T-shaped reinforcement nail into the brake pad; S7, vacuum-sealing and co-curing the wearing layer, brake pad backing plate, and composite material T-shaped reinforcement nail; S8, curing and molding. The present invention can reduce the wear of the brake pad, enhance the stability of the brake pad, and improve the performance and service life of the brake pad.

Description

Technical Field

[0001] The present invention relates to the technical field of rail transit vehicles, and in particular to a composite brake pad for rail vehicles and a molding method thereof. Background Art

[0002] With the rapid development of rail transit and the increasing crisscrossing of high-speed rail networks, vehicle operational safety is receiving increasing attention. Brake pads, as key components of rail vehicles such as passenger cars, are primarily used for emergency braking. When the vehicle is in motion, the brake pads remain relatively stationary. When braking is required, a braking torque is generated by the braking system and transmitted to the brake pads to achieve the braking function. The performance of brake pads directly determines the reliability and operational safety of rail vehicles. The following prior art patents relate to brake pads for rail vehicles or methods for forming them:

[0003] 1. The patent number is "201910219339.3", and the patent name is "Rail Transit Vehicle Brake Pad and Preparation Method Thereof". The brake pad includes a steel back, a friction block and a connecting plate. By adding a grid-shaped connecting plate inside the friction block, the friction material of the friction block is filled between the grids of the connecting plate. This can solve the problem of the friction block falling off during braking due to the low bonding strength of the part of the friction block that is larger than the steel back area.

[0004] 2. The patent number is "202010654201.9", and the patent name is "A brake pad and its manufacturing method". The friction body includes a base component, a lubricating component and a friction component. The steel back is provided with a groove that matches the shape of the friction body. It can solve the problems of edge loss, corner loss, block loss, metal inlay, abnormal wear, etc. of the brake pad during the braking process of heavy-loaded locomotives.

[0005] 3. The invention patent with the patent number "201710136827.9" and the patent name "A powder metallurgy brake pad for EMU" includes a steel back plate, a dovetail block and multiple brake pad friction bodies. The steel back plate and the dovetail block are an integrated molding structure. The brake pad can increase the rigidity and reliability of the steel back, simplify the processing and riveting processes, reduce the production cost of the brake pad, and improve the reliability and life of the brake pad.

[0006] However, the above existing brake pads and manufacturing methods have the following shortcomings:

[0007] 1. As the braking speed increases, the brake pads made of cast iron or steel will cause the pad temperature to rise, the friction coefficient to decrease, and the wear to increase, which will lead to a short service life of the brake pads and unstable friction performance.

[0008] 2. Powder metallurgy brake pads use powder metallurgy technology to make friction blocks, which are fixed to the back plate by riveting or welding. This manufacturing process has very high requirements on the connection method between the friction block and the back plate, and it is easy to cause problems such as brake pad falling off.

[0009] 3. In the one-piece molded brake pad, the manufacturing process of the integrated brake pad cannot effectively solve the gas emission problem during the matrix curing process, which easily leads to cracking and internal defects of the friction material products and cannot guarantee the friction performance of the brake pad.

[0010] To sum up, how to design a rail vehicle brake pad and its forming method that can enhance the friction coefficient stability of the brake pad, reduce the wear of the brake pad, avoid internal gaps and block falling problems, and have excellent structural stability and reliability is a problem that needs to be solved urgently. Summary of the Invention

[0011] To solve the above-mentioned problems, the present invention provides a composite brake pad for rail vehicles and a molding method thereof. By designing and molding composite T-shaped reinforcement nails, a composite wear layer, and a composite brake pad back plate, the friction coefficient stability and thermal stability of the brake pad can be effectively enhanced, the wear of the brake pad can be reduced, the interlayer bonding force of the brake pad can be enhanced, the generation of internal gaps or microcracks can be avoided, peeling can be prevented, and the performance and service life of the brake pad can be improved.

[0012] To achieve the above-mentioned object, the present invention proposes the following technical solution: a method for forming a composite brake pad for a rail vehicle, comprising the following steps:

[0013] S1. Prepare 3K carbon cloth / barium phenolic prepreg;

[0014] S2. Manufacturing composite material T-shaped reinforcement nails and pre-installing the composite material T-shaped reinforcement nails on a forming mold for the brake pad;

[0015] S3. Lay 3K carbon cloth / barium phenolic prepreg on the forming mold to form a wear layer. During the laying process, keep the pre-installed composite T-shaped reinforcement nails fully inserted into the wear layer;

[0016] S4, making high silica cloth / barium phenolic prepreg;

[0017] S5. Laying a high-silica cloth / barium phenolic prepreg with prefabricated holes on top of the wear layer to form a brake pad backing plate;

[0018] S6. Implanting a composite material T-shaped reinforcement nail into the interior of the brake pad through the prefabricated hole of the high-silica cloth / barium phenolic prepreg, such that the composite material T-shaped reinforcement nail penetrates the wearing layer and is inserted into the brake pad backing plate to connect the brake pad backing plate to the wearing layer;

[0019] S7, vacuum-packing the wearing layer, the brake pad back plate, and the composite material T-shaped reinforcement nails as a whole, and co-curing after packaging;

[0020] S8. The brake pad is solidified and formed, and the outer surface of the brake pad is processed.

[0021] Preferably, in step S2, the composite material T-shaped reinforcement nails are pre-installed on the brake pad forming mold in a pyramid array, and the T-shaped nail heads of the composite material T-shaped reinforcement nails are kept perpendicular to the friction direction of the brake pad.

[0022] Preferably, blanking sample one and blanking sample two are designed respectively according to the design requirements of the wear layer and the brake pad back plate, and blanking sample one and blanking sample two are used as samples to produce 3K carbon cloth / barium phenolic prepreg and high silica cloth / barium phenolic prepreg respectively through a CNC cutting machine.

[0023] Preferably, the T-shaped reinforcement nail is made of carbon / carbon composite material according to the design requirements of the composite material T-shaped reinforcement nail.

[0024] Preferably, the length L1 of the T-shaped nail head in the composite material T-shaped reinforced nail is 12mm-14mm, the width L2 of the T-shaped nail head is 11mm-13mm, and the thickness L3 of the T-shaped nail head is 2mm-4mm; the length L4 of the vertical nail rod in the composite material T-shaped reinforced nail is 11mm-13mm, and the diameter R of the vertical nail rod is 2mm-4mm.

[0025] Preferably, the thickness of the wear layer in step S3 is 18 mm to 20 mm.

[0026] Preferably, in step S5, the thickness of the gate shoe back plate is 11.5 mm to 14 mm.

[0027] Preferably, the curing temperature in step S7 is 70° C.-170° C., the curing time is 3 h-50 h, and the curing pressure is 3 MPa-6 MPa.

[0028] A composite brake pad for rail vehicles is prepared by the above-mentioned molding method, comprising a wearing layer, a brake pad back plate and a composite material T-shaped reinforcement nail, wherein the brake pad back plate is located above the wearing layer; the brake pad back plate and the wearing layer respectively include corresponding prefabricated holes and receiving holes for implanting the composite material T-shaped reinforcement nails.

[0029] Preferably, the prefabricated hole is a circular hole, the receiving hole is a rectangular hole, and the aperture of the prefabricated hole is not larger than the width of the receiving hole; the composite material T-shaped reinforcement nail includes a T-shaped nail head and a vertical nail rod connected to the T-shaped nail head, the T-shaped nail head is a rectangular hole set corresponding to the receiving hole and can be inserted into the receiving hole, the T-shaped nail rod is a cylindrical rod set corresponding to the prefabricated hole and can penetrate the wear layer and be inserted into the brake pad back plate to connect the brake pad back plate with the wear layer; the T-shaped nail head is set perpendicular to the friction direction of the brake pad.

[0030] The beneficial effects of the present invention are:

[0031] 1. The composite T-shaped reinforcement nails in the present invention are made of carbon / carbon composite material and pre-installed in a pyramid-shaped array, which can reduce the damage of the composite T-shaped reinforcement nails to the fibers and improve the thermal stability of the brake pad during the wear process, thereby enhancing the shear strength of the brake pad wearing layer.

[0032] 2. The T-shaped structure of the composite material T-shaped reinforcement nail in the present invention is arranged perpendicular to the friction direction of the brake pad, and the composite material T-shaped reinforcement nail is embedded into the interior of the brake pad by pre-embedding and connects the brake pad back plate to the wear layer; it can effectively inhibit the occurrence of interlayer delamination and greatly improve the wear resistance of the brake pad surface.

[0033] 3. The present invention performs a co-curing operation on the wear layer of the brake pad, the brake pad backing plate and the composite material T-shaped reinforcement nails, which can avoid the generation of internal gaps in the structure and avoid the micro-cracks or cracks in the product due to different thermal expansion coefficients caused by repeated heating in the traditional staged curing method, thereby improving the structural stability and reliability of the product.

[0034] 4. The brake pads of the present invention are made of composite materials and have the advantages of stable friction coefficient, small wear, good thermal stability, low noise and low density. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic structural diagram of a brake pad provided by an embodiment of the present invention.

[0036] Figure 2 yes Figure 1 Cross-sectional view in the AA direction.

[0037] Figure 3 3K carbon cloth / barium phenolic prepreg is provided in an embodiment of the present invention to form a lower sample plate for forming a wear layer.

[0038] Figure 4 1 is a schematic structural diagram of a lower sample plate 2 for making a high-silica cloth / barium phenolic prepreg to form a brake pad back plate, provided in an embodiment of the present invention.

[0039] Figure 5 It is a schematic diagram of the structure of a carbon / carbon composite material T-shaped reinforcement nail provided by an embodiment of the present invention.

[0040] Figure 6 It is a schematic top view of a brake pad forming method provided by an embodiment of the present invention.

[0041] Figure 7 It is a front view schematic diagram of the brake pad forming method provided by an embodiment of the present invention.

[0042] Figure numerals: 1, wearing layer; 2, gate pad back plate; 3, T-shaped reinforcement nail; 3a, T-shaped nail head; 3b, vertical nail rod; 4, left gate pad blanking template 2; 5, right gate pad blanking template 2; 6, left gate pad blanking template 1; 7, right gate pad blanking template 1; 8, forming mold bottom plate; 9, prefabricated hole; 10, heat dissipation groove; 11, receiving hole. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solutions and advantages of the present invention more clear, the following Figure 1-7 It should be understood that the specific embodiments described herein are only used to illustrate the present invention and do not constitute a limitation of the present invention.

[0044] A method for forming a composite brake pad for a rail vehicle comprises the following steps:

[0045] S1. Design a blanking sample according to the design requirements of the wear layer 1 and use the blanking sample 1 as a sample to produce 3K carbon cloth / barium phenolic prepreg through a CNC cutting machine; Figure 3 As shown, the wear layer 1 includes a left gate pad blanking template 6 and a right gate pad blanking template 7, and the left gate pad blanking template 6 and the right gate pad blanking template 7 include rectangular receiving holes 11 symmetrically arranged in a pyramid array.

[0046] S2, making composite material T-shaped reinforcement nails 3 and pre-installing the composite material T-shaped reinforcement nails 3 on the forming mold of the brake pad; making T-shaped reinforcement nails 3 using carbon / carbon composite materials according to the design requirements of the composite material T-shaped reinforcement nails 3; pre-installing the composite material T-shaped reinforcement nails 3 in a pyramid array as shown in FIG. Figure 6 On the molding die bottom plate 8 of the brake pad shown in FIG, the pyramidal array is as follows Figure 6 As shown in the S in the middle;

[0047] like Figure 5As shown, the composite material T-shaped reinforcement nail 3 includes a T-shaped nail head 3a and a vertical nail rod 3b connected to the T-shaped nail rod. The T-shaped nail head 3a is a rectangular hole arranged corresponding to the accommodating hole 11 and can be inserted into the accommodating hole 11, keeping the T-shaped nail head 3a of the composite material T-shaped reinforcement nail 3 perpendicular to the friction direction of the brake pad to improve the interlayer bonding force of the brake pad.

[0048] S3, such as Figure 6 and Figure 7 As shown, 3K carbon cloth / barium phenolic prepreg is laid on the forming mold to form a wear layer 1. During the laying process, the pre-installed composite material T-shaped reinforcement nails 3 are kept completely inserted into the wear layer 1; the thickness of the wear layer 1 is 18mm-20mm, preferably 19mm.

[0049] S4. Design a second blanking sample according to the design requirements of the brake pad back plate 2 and use the second blanking sample as a sample to make high silica cloth / barium phenolic prepreg through a CNC cutting machine; Figure 3 As shown, the gate pad back plate 2 includes a left gate pad blanking template 2 4 and a right gate pad blanking template 2 5 , and the left gate pad blanking template 2 4 and the right gate pad blanking template 2 5 include circular prefabricated holes 9 symmetrically arranged in a pyramid array.

[0050] S5. Lay the high-silica cloth / barium phenolic prepreg with prefabricated holes 9 on the wear layer 1 to form a brake pad back plate 2; wherein the laying thickness of the brake pad back plate 2 is 11.5 mm-14 mm, preferably 12.9 mm.

[0051] S6, the T-shaped nail rod is a cylindrical rod arranged corresponding to the prefabricated hole 9. The composite material T-shaped reinforcement nail 3 is implanted into the interior of the brake pad through the prefabricated hole 9 of the high-silica cloth / barium phenolic prepreg, so that the composite material T-shaped reinforcement nail 3 penetrates the wearing layer 1 and is inserted into the brake pad back plate 2 to connect the brake pad back plate 2 to the wearing layer 1;

[0052] Among them, such as Figure 5 As shown, the length L1 of the T-shaped nail head 3a in the composite material T-shaped reinforcement nail 3 is 12mm-14mm, preferably 13mm; the width L2 of the T-shaped nail head 3a is 11mm-13mm, preferably 12mm; the thickness L3 of the T-shaped nail head 3a is 2mm-4mm, preferably 3mm; the length L4 of the vertical nail rod 3b in the composite material T-shaped reinforcement nail 3 is 11mm-13mm, preferably 12mm; the diameter R of the vertical nail rod 3b is 2mm-4mm, preferably 3mm.

[0053] S7. The wearing layer 1, the brake pad back plate 2 and the composite material T-shaped reinforcement nail 3 are vacuum-packaged as a whole, and then co-cured after packaging; wherein the curing temperature is 70°C-170°C, the curing time is 3h-50h, and the curing pressure is 3Mpa-6Mpa.

[0054] S8. After the brake pad is solidified and formed, the outer surface of the brake pad is processed. The finished brake pad is obtained, such as Figure 1 As shown, in the later processing, a heat dissipation groove 10 is provided on the brake pad to dissipate heat.

[0055] A composite brake pad for rail vehicles is prepared by the above molding method, such as Figure 6 and Figure 7 As shown, it includes a wearing layer 1, a brake pad back plate 2 and a composite material T-shaped reinforcement nail 3, and the brake pad back plate 2 is located above the wearing layer 1; the brake pad back plate 2 and the wearing layer 1 respectively include corresponding prefabricated holes 9 and receiving holes 11 for implanting the composite material T-shaped reinforcement nail 3; wherein the prefabricated hole 9 is a circular hole, and the receiving hole 11 is a rectangular hole, and the aperture of the prefabricated hole 9 is not greater than the width of the receiving hole 11; as shown Figure 5 As shown, the composite material T-shaped reinforcement nail 3 includes a T-shaped nail head 3a and a vertical nail rod 3b connected to the T-shaped nail head 3a. The T-shaped nail head 3a is a rectangular hole arranged corresponding to the accommodating hole 11 and can be inserted into the accommodating hole 11. The T-shaped nail rod is a cylindrical rod arranged corresponding to the prefabricated hole 9 and can penetrate the wear layer 1 and be inserted into the brake pad back plate 2 to connect the brake pad back plate 2 with the wear layer 1; the T-shaped nail head 3a is arranged perpendicular to the friction direction of the brake pad; the wearing layer 1 and the brake pad back plate 2 are firmly connected through the composite material T-shaped reinforcement nail 3, the accommodating hole 11 and the prefabricated hole 9.

[0056] Although the embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art may make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

[0057] The above specific embodiments of the present invention do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the scope of protection of the claims of the present invention.

Claims

1. A method for forming a composite brake pad for a rail vehicle, characterized in that: The steps include: S1. Prepare 3K carbon cloth / barium phenolic prepreg; S2, making a composite material T-shaped reinforcement nail (3) and pre-installing the composite material T-shaped reinforcement nail (3) on a forming mold of a brake pad; S3, laying 3K carbon cloth / barium phenolic prepreg on the forming mold to form a wear layer (1), and during the laying process, keeping the pre-installed composite material T-shaped reinforcement nails (3) completely inserted into the wear layer (1); S4, making high silica cloth / barium phenolic prepreg; S5, laying a high-silica cloth / barium phenolic prepreg with prefabricated holes (9) on top of the wear layer (1) to form a brake pad back plate (2); S6. Implanting the composite material T-shaped reinforcement nail (3) into the interior of the brake pad through the prefabricated hole (9) of the high-silica cloth / barium phenolic prepreg, so that the composite material T-shaped reinforcement nail (3) penetrates the wearing layer (1) and is inserted into the brake pad back plate (2) to connect the brake pad back plate (2) and the wearing layer (1); S7, vacuum-packing the wear layer (1), the brake pad back plate (2), and the composite material T-shaped reinforcement nail (3) as a whole, and co-curing after the packaging is completed; S8. The brake pad is solidified and formed, and the outer surface of the brake pad is processed.

2. The molding method of composite brake pad for rail vehicles according to claim 1, characterized in that: In step S2, the composite material T-shaped reinforcement nails (3) are pre-installed on the brake pad forming die in a pyramid array manner, and the T-shaped nail heads (3a) of the composite material T-shaped reinforcement nails (3) are kept perpendicular to the friction direction of the brake pad.

3. The molding method of composite brake pad for rail vehicles according to claim 2, characterized in that: According to the design requirements of the wear layer (1) and the brake pad back plate (2), a blanking sample 1 and a blanking sample 2 are designed respectively, and the blanking sample 1 and the blanking sample 2 are used as samples to respectively produce 3K carbon cloth / barium phenolic prepreg and high silica cloth / barium phenolic prepreg by a CNC cutting machine.

4. The method for forming a composite brake pad for rail vehicles according to claim 3, characterized in that: According to the design requirements of the composite material T-shaped reinforcement nail (3), the T-shaped reinforcement nail (3) is made of a carbon / carbon composite material.

5. The molding method of composite brake pad for rail vehicles according to claim 4, characterized in that: The length L1 of the T-shaped nail head (3a) in the composite material T-shaped reinforcement nail (3) is 12 mm to 14 mm, the width L2 of the T-shaped nail head (3a) is 11 mm to 13 mm, and the thickness L3 of the T-shaped nail head (3a) is 2 mm to 4 mm; the length L4 of the vertical nail rod (3b) in the composite material T-shaped reinforcement nail (3) is 11 mm to 13 mm, and the diameter R of the vertical nail rod (3b) is 2 mm to 4 mm.

6. The method for forming a composite brake pad for rail vehicles according to any one of claims 1 to 5, characterized in that: The thickness of the wear layer (1) in step S3 is 18 mm to 20 mm.

7. The method for forming a composite brake pad for rail vehicles according to claim 6, characterized in that: The thickness of the gate plate back plate (2) in step S5 is 11.5 mm to 14 mm.

8. The method for forming a composite brake pad for rail vehicles according to claim 7, characterized in that: The curing temperature in step S7 is 70° C.-170° C., the curing time is 3 h-50 h, and the curing pressure is 3 MPa-6 MPa.

9. A composite brake pad for rail vehicles, characterized in that: Prepared by the molding method according to any one of claims 1 to 8, comprising a wearing layer (1), a brake pad back plate (2) and a composite material T-shaped reinforcing nail (3), wherein the brake pad back plate (2) is located above the wearing layer (1); the brake pad back plate (2) and the wearing layer (1) respectively include corresponding prefabricated holes (9) and receiving holes (11) for implanting the composite material T-shaped reinforcing nail (3).

10. The composite brake pad for railway vehicles according to claim 9, characterized in that: The prefabricated hole (9) is a circular hole, and the receiving hole (11) is a rectangular hole. The diameter of the prefabricated hole (9) is not greater than the width of the receiving hole (11). The composite material T-shaped reinforcement nail (3) comprises a T-shaped nail head (3a) and a vertical nail rod (3b) connected to the T-shaped nail head (3a). The T-shaped nail head (3a) is a rectangular hole corresponding to the receiving hole (11) and can be inserted into the receiving hole (11). The vertical nail rod is a columnar rod corresponding to the prefabricated hole (9) and can penetrate the wear layer (1) and be inserted into the brake pad back plate (2) to connect the brake pad back plate (2) and the wear layer (1). The T-shaped nail head (3a) is arranged perpendicular to the friction direction of the brake pad.

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