Bimetallic composite brake disc and method of manufacture

Abstract

The application belongs to the technical field of automobile parts, and provides a bimetallic composite brake disc and a manufacturing method, wherein the bimetallic composite brake disc comprises an annular disc body and a connecting flange, the connecting flange comprises a cylindrical main body, a connecting disc integrally connected with the cylindrical main body is arranged at a first end of the cylindrical main body, a gear ring integrally connected with the cylindrical main body is arranged at a second end of the cylindrical main body, an outwardly extending connecting part is arranged on an outer circumferential surface of the cylindrical main body close to the second end, and the connecting part is fixedly connected with an inner ring of the annular disc body. The bimetallic composite brake disc provided by the application designs the gear ring and the connecting flange as an integral steel part, thereby fundamentally eliminating the risk of gear ring falling caused by loosening and failure of the connecting part, and having the advantages of high safety, light weight, long service life and high reliability.

Description

Technical Field

[0001] This invention belongs to the field of automotive parts technology, and in particular relates to a bimetallic composite brake disc and its manufacturing method. Background Technology

[0002] Brake discs are the core component of a vehicle's disc braking system, primarily functioning to work with the brakes to achieve vehicle braking. Currently, commercial vehicle brake discs mainly include single-material gray cast iron brake discs and bimetallic composite brake discs. Among them, bimetallic composite brake discs, through material and structural innovations, outperform traditional gray cast iron brake discs in terms of heat dissipation, durability, lightweight design, and braking experience. However, further weight reduction, improved heat dissipation, and extended lifespan still face challenges.

[0003] In existing technologies, the gear ring of bimetallic composite brake discs often adopts a split structure. For example, Chinese patent CN219549447U discloses a steel composite brake disc with an ABS gear ring, where the ABS gear ring is a separate part connected to the connector by fasteners. This structure poses a safety hazard as the gear ring may loosen during use, and the additional connector also increases the overall weight.

[0004] While single-material gray cast iron brake discs can be integrally cast with the gear ring and disc body (as in Chinese patent CN211599353U), this integral structure suffers from significant defects due to the inherent properties of gray cast iron: 1. Brittle fracture, chipping, and spalling at the tooth root: Under alternating and impact loads, the stress concentration area at the tooth root is prone to brittle fractures such as chipping and spalling. 2. Poor fatigue resistance: Under long-term ABS / retardation / drive load cycles, fatigue cracks initiate extremely quickly, resulting in a lifespan far shorter than that of steel gear rings. 3. Large casting shrinkage and deformation, making it difficult to guarantee tooth precision: The brake disc body is large and has uneven wall thickness. Inconsistent shrinkage during casting cooling leads to elliptical, wobbly, and large end face runout in the gear ring area, making it difficult to consistently achieve the gear / gear ring precision level after machining (usually only low precision is possible). 4. Casting defects directly fall in the dangerous area of ​​the teeth: Common defects in gray cast iron casting include shrinkage cavities, porosity, gas holes, sand holes, slag inclusions, and cold shuts. These defects, once they appear at the tooth root, tooth surface, or transition fillet, become fatigue sources, directly leading to early failure. 5. Inability to locally optimize materials and performance: Brake discs require high thermal conductivity, high damping, and high wear resistance; while gear rings require high strength, high toughness, and high fatigue resistance. One-piece casting can only use the same grade of gray cast iron, resulting in compromises in performance, making it impossible to achieve optimal performance in both areas. 6. Impact of thermal fade: Braking generates a large amount of heat → the entire brake disc heats up → gray cast iron has lower high-temperature strength and more pronounced brittleness → the teeth are more prone to failure. In summary, when gray cast iron brake discs and gear rings are integrally cast, due to the material's high brittleness, uncontrollable casting defects, large thermal deformation, inability to strengthen or repair, difficulty in guaranteeing precision, and poor fatigue and impact performance, tooth root fracture, chipping, signal inaccuracy, and overall early failure are likely to occur. Furthermore, after-sales maintenance costs are high, making it only suitable for low-load, low-speed, non-safety-critical, and low-precision applications, and unsuitable for medium-heavy load, high-speed, ABS / electronic braking, and other mainstream scenarios. In addition, the integral casting flange of the gray cast iron brake disc connects to a single-sided friction surface, resulting in unreasonable stress distribution and affecting heat dissipation.

[0005] For bimetallic composite brake discs, the use of a separate gear ring design has become a common practice in the industry. This is mainly based on two reasons: First, structurally, the connecting flange or connector needs to be combined with the disc body through a flanged fusion plate, and the manufacturing process of the connecting flange or connector is flanging and stamping at room temperature, which is not conducive to the integration of the gear ring; Second, considering manufacturing and maintenance costs, separate standard gear rings are easier to purchase and can be replaced individually when damaged, reducing operating costs. To reduce weight, some bimetallic composite brake discs integrate the gear ring and disc body into one piece, such as the highly integrated lightweight brake disc disclosed in Chinese patent CN220488158U. However, it has the same drawback as the gear ring of the single-material gray cast iron brake disc analyzed earlier, namely, the brake disc needs high thermal conductivity, high damping, and high wear resistance; the gear ring needs high strength, high toughness, and high fatigue resistance. One-piece casting can only use the same grade of gray cast iron, resulting in a compromise in performance and an inability to achieve both.

[0006] In summary, existing bimetallic composite brake discs face a dilemma in their gear ring structure: split designs suffer from shortcomings in connection reliability and weight, while attempts at a one-piece design are limited by unbalanced material properties or manufacturing biases. Therefore, a novel bimetallic composite brake disc structure is urgently needed that can achieve further weight reduction while maintaining high safety, thus addressing the shortcomings of existing technologies. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a bimetallic composite brake disc and a manufacturing method thereof. The bimetallic composite brake disc has the advantages of high safety, light weight, long service life and high reliability.

[0008] This application provides a bimetallic composite brake disc, including an annular disc body and a connecting flange. The connecting flange includes a cylindrical body. A connecting disc is integrally connected to the cylindrical body at a first end, and a toothed ring is integrally connected to the cylindrical body at a second end. An outwardly extending connecting portion is provided on the outer circumferential surface of the cylindrical body near the second end, and the connecting portion is fixedly connected to the inner ring of the annular disc body.

[0009] As a further description of the above technical solution, the tooth width of the gear ring is greater than the wall thickness of the cylindrical body.

[0010] As a further description of the above technical solution, the connecting part includes a plurality of fusion plates evenly distributed on the outer circumferential surface of the cylindrical body, the annular disk includes two friction disks spaced apart and a reinforcing rib connected between the two friction disks, and a portion of the fusion plate is inserted between the two friction disks and is metallurgically joined to the side of the two friction disks facing each other.

[0011] As a further description of the above technical solution, the inner diameter of the gear ring is the same as the inner diameter of the cylindrical body, and the outer diameter of the root of the fusion plate is the same as the outer diameter of the gear ring.

[0012] As a further description of the above technical solution, the connecting flange is manufactured using spinning and machining processes.

[0013] As a further description of the above technical solution, the connecting flange is manufactured using a heated stamping forming process.

[0014] As a further description of the above technical solution, a casting-molded connecting claw is provided between the two friction discs, the connecting claw covers the outer wall of the fusion plate, and the reinforcing rib includes a plurality of circumferentially distributed outer ribs and a plurality of inner ribs.

[0015] The outer rib is set as an oblique arc rib and is located on the disk surface on the radially outer side of the connecting claw. Its cross-sectional width gradually increases from the outer end to the inner end, so that a diffuser air duct is formed between two adjacent outer ribs from the outside to the inside.

[0016] The inner rib is located on the disc surface between two adjacent connecting claws, and its cross-sectional width gradually increases from the inner end to the outer end, so that the inner rib and the adjacent connecting claws form a diffuser-type air duct from the inside to the outside.

[0017] As a further description of the above technical solution, the width of the inner end of the inner rib is d1, the width of the outer end is d2, the width of the inner end of the outer rib is d3, and the width of the outer end is d4, which satisfies: d1:d2:d3:d4=1:(1.7-1.8):(1.7-1.8):1.3.

[0018] As a further description of the above technical solution, among the two opposing friction discs, the inner disc surface is provided with an inclined angle that widens towards the center, and the outer disc surface is provided with an inclined angle that widens towards the outer edge.

[0019] As a further description of the above technical solution, the surfaces of the two friction discs on opposite sides are distributed with micro-diamond-shaped airflow guide ribs, and micro-air ducts are formed between adjacent micro-diamond-shaped airflow guide ribs, with the extension direction being consistent with the extension direction of the outer and inner ribs.

[0020] As a further description of the above technical solution, the surface of the air duct formed between the two friction discs is coated with a high-silicon aluminum alloy layer.

[0021] As a further description of the above technical solution, the transverse centerline of the air duct formed between the two friction discs is offset away from the transverse centerline of the annular disc in a direction away from the connecting disc.

[0022] As a further description of the above technical solution, the annular disk includes a high-strength structural layer in the middle and long-term wear-resistant layers covering its two end faces. The long-term wear-resistant layers are made of a nickel-based self-fluxing alloy as the matrix, wherein WC, TiC, and [other alloys are present in the matrix]. Mixed hard phase particles, and added and Rare earth oxides.

[0023] As a further description of the above technical solution, the long-lasting wear layer is formed on the high-strength structural layer by laser cladding process.

[0024] This application provides a method for manufacturing a bimetallic composite brake disc, including a method for manufacturing a connecting flange, the method for manufacturing the connecting flange comprising the following steps:

[0025] Step 1: Provide a circular disc blank, and use a spinning process to form the shape of a connecting disc to obtain a primary steel shell;

[0026] Step 2: Place the primary steel shell in the mold for spinning. Set a groove at the root of the mold to leave enough material for the gear ring. First, use a coarse spinning wheel to spin out the overall outline, and then use a fine spinning wheel to finish it, to obtain a shaped steel shell with a cylindrical body and a reserved gear ring material part. The radius of the coarse spinning wheel tip is larger than the radius of the arc of the shaped steel shell. The larger radius of the arc is to fill the groove and leave enough material.

[0027] Step 3: Punch the formed steel shell to form the connecting part;

[0028] Step 4: Machining tooth profiles on the reserved toothed ring material to form a toothed ring.

[0029] As a further description of the above technical solution, the material of the circular disc blank is 380CL or 420CL steel.

[0030] This application also provides a method for manufacturing a bimetallic composite brake disc, including a method for manufacturing a connecting flange, the method for manufacturing the connecting flange comprising the following steps:

[0031] Step 1: Provide the circular dough ring;

[0032] Step 2: Heat the outer ring region of the circular disc blank to above the recrystallization temperature;

[0033] Step 3: Stretch and stamp the heated blank to form a connecting flange blank;

[0034] Step 4: Machining a gear ring at the end of the blank.

[0035] This invention provides a bimetallic composite brake disc that integrates the gear ring and connecting flange into a single steel component, fundamentally eliminating the risk of gear ring detachment due to loose or failed connectors. This significantly improves the safety of the brake disc under complex conditions such as high speed and heavy load. Simultaneously, eliminating the fasteners for the gear ring directly reduces the weight of the brake disc, contributing to vehicle lightweighting. Furthermore, the connecting flange and the annular disc body can be made of different materials, successfully avoiding the inherent material and manufacturing defects of existing gray cast iron integrated gear rings. The connecting flange (including the gear ring) uses high-strength, high-toughness steel specifically designed to meet the stringent mechanical performance requirements of the gear ring; while the annular disc body can still be made of high thermal conductivity, high-damping cast iron (such as HT250), optimally maximizing braking and heat dissipation functions. Moreover, since the back of the gear ring is the cylindrical wall of the main body, it possesses sufficient rigidity and strength, preventing deformation during use and ensuring high reliability. Therefore, the bimetallic composite brake disc provided by this invention offers advantages such as high safety, light weight, long service life, and high reliability.

[0036] This invention provides a method for manufacturing a bimetallic composite brake disc. Through a step-by-step spinning process, the stress on the equipment is effectively reduced. Combined with mold grooves and variable-speed spinning, sufficient and dense material is reserved for the gear ring, improving material utilization and microstructure density. Simultaneously, the use of efficient processing methods such as gear hobbing improves production efficiency while ensuring quality.

[0037] The present invention provides another method for manufacturing a bimetallic composite brake disc, which significantly improves the plasticity and flowability of the material by locally heating the outer ring of the circular disc blank, creating favorable conditions for subsequent gear ring forming. At the same time, it can reduce the stress on the equipment and save energy consumption, while effectively enhancing the comprehensive mechanical properties of the connecting flange through grain refinement and continuous fiber streamline distribution. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 This is a three-dimensional structural diagram of a bimetallic composite brake disc provided in a specific embodiment of the present invention.

[0040] Figure 2 This is a top view of a bimetallic composite brake disc provided in a specific embodiment of the present invention.

[0041] Figure 3for Figure 2 One of the schematic diagrams of the AA cross-sectional structure.

[0042] Figure 4 This is a top view of a circular disc blank provided in a specific embodiment of the present invention.

[0043] Figure 5 This is a schematic diagram of the front cross-sectional structure of a circular disc blank provided in a specific embodiment of the present invention.

[0044] Figure 6 This is a schematic diagram of the main cross-sectional structure of the primary steel shell provided in a specific embodiment of the present invention.

[0045] Figure 7 This is a schematic diagram of the main cross-sectional structure of a molded steel shell provided in a specific embodiment of the present invention.

[0046] Figure 8 This is a schematic diagram of the mold spinning state provided in a specific embodiment of the present invention.

[0047] Figure 9 This is a schematic diagram of the structure of a connecting flange blank provided in a specific embodiment of the present invention.

[0048] Figure 10 This is a schematic diagram of the connecting flange provided in a specific embodiment of the present invention.

[0049] Figure 11 for Figure 3 Schematic diagram of the BB cross-section structure.

[0050] Figure 12 This is a schematic diagram of airflow between two friction discs, provided as a specific embodiment of the present invention.

[0051] Figure 13 This is a partial cross-sectional structural diagram provided for a specific embodiment of the present invention.

[0052] Figure 14 for Figure 2 The second schematic diagram of the AA cross-sectional structure.

[0053] Figure 15 for Figure 2 The third schematic diagram of the AA cross-sectional structure.

[0054] The following labels are shown in the attached diagram:

[0055] 1. Annular disc; 11. Friction disc; 12. Connecting claw; 13. Outer rib; 14. Inner rib; 15. Miniature diamond-shaped air guide rib; 16. Miniature air duct; 17. Lateral centerline of the air duct; 18. Lateral centerline of the annular disc; 101. High-strength structural layer; 102. Long-lasting wear layer; 2. Connecting flange; 21. Cylindrical body; 22. Connecting disc; 23. Gear ring; 24. Fusion plate; 31. Circular disc blank; 32. Primary steel shell; 33. Formed steel shell; 331. Reserved gear ring material section; 34. Connecting flange blank; 4. Mold; 41. Groove; 42. Coarse spinning wheel; 43. Fine spinning wheel. Detailed Implementation

[0056] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0057] Please refer to Figures 1 to 15 , Figure 1 This is a three-dimensional structural schematic diagram of a bimetallic composite brake disc provided in a specific embodiment of the present invention; Figure 2 This is a top view of a bimetallic composite brake disc provided in a specific embodiment of the present invention. Figure 3 for Figure 2 One of the schematic diagrams of the AA cross-sectional structure; Figure 4 This is a top view of a circular disc blank provided in a specific embodiment of the present invention; Figure 5 This is a schematic diagram of the front cross-sectional structure of a circular disc blank provided in a specific embodiment of the present invention; Figure 6 This is a schematic diagram of the main cross-sectional structure of a primary steel shell provided in a specific embodiment of the present invention. Figure 7 This is a schematic diagram of the main sectional view of a molded steel shell provided in a specific embodiment of the present invention; Figure 8 This is a schematic diagram of the die spinning state provided in a specific embodiment of the present invention; Figure 9 This is a schematic diagram of the structure of a connecting flange blank provided in a specific embodiment of the present invention; Figure 10 This is a schematic diagram of the structure of a connecting flange provided in a specific embodiment of the present invention; Figure 11 for Figure 4 Schematic diagram of the BB cross-sectional structure; Figure 12 This is a schematic diagram of airflow between two friction discs provided in a specific embodiment of the present invention; Figure 13 This is a partial cross-sectional structural schematic diagram provided for a specific embodiment of the present invention; Figure 14 for Figure 2 AA sectional view structural diagram 2; Figure 15 for Figure 2 The third schematic diagram of the AA cross-sectional structure.

[0058] like Figures 1-3 As shown, the bimetallic composite brake disc provided in this embodiment of the invention mainly includes an annular disc body 1 and a connecting flange 2. The connecting flange 2 has a cylindrical body 21, with an integrally formed connecting disc 22 (for connecting the wheel hub) at the first end of the cylindrical body 21, and an integrally formed toothed ring 23 (for ABS signal acquisition) at the second end. On the outer peripheral surface of the cylindrical body 21 near the second end, there is an outwardly extending connecting portion, which is used for fixed connection with the inner ring of the annular disc body 1.

[0059] The bimetallic composite brake disc provided in this embodiment of the invention integrates the gear ring 23 and the connecting flange 2 into a single steel component, eliminating the mechanical connection methods such as bolts and screws relied upon by the traditional separate gear ring 23. This design fundamentally eliminates the risk of the gear ring 23 detaching due to loosening or failure of the connecting parts, significantly improving the safety of the brake disc under complex conditions such as high speed and heavy load. Simultaneously, eliminating the fasteners for the gear ring 23 directly reduces the weight of the brake disc, contributing to vehicle lightweighting.

[0060] Furthermore, the connecting flange 2 and the annular disc 1 can be made of different materials, successfully avoiding the inherent material and process defects of the existing gray cast iron integrated gear ring 23. The connecting flange 2 (including the gear ring 23) is made of high-strength and high-toughness steel, specifically to meet the stringent mechanical performance requirements of the gear ring 23; while the annular disc 1 can still be made of high thermal conductivity and high damping cast iron (such as HT250), to optimally perform braking and heat dissipation functions. Moreover, since the back of the gear ring 23 is the cylindrical wall of the cylindrical body 21, it has sufficient rigidity and strength, so it will not deform during use, resulting in high reliability.

[0061] Therefore, the bimetallic composite brake disc provided in this embodiment of the invention has the advantages of high safety, light weight and long service life.

[0062] In some embodiments, such as Figure 3 As shown, the tooth width of the gear ring 23 is designed to be greater than the wall thickness of the cylindrical body 21 to ensure sufficient structural strength. Additionally, the cylindrical body 21 has a relatively thin wall thickness, which, while ensuring the structural strength of the connecting flange 2, also meets the lightweight design requirements of the brake disc.

[0063] In some embodiments, such as Figure 2 and Figure 3As shown, the connecting part includes multiple fusion plates 24 evenly distributed on the outer circumference of the cylindrical body 21. The annular disc 1 is composed of two spaced friction discs 11 and reinforcing ribs connecting them. A portion of the fusion plate 24 is inserted between the two friction discs 11 and is firmly bonded to the opposite side of the two friction discs 11 by metallurgy. The annular disc 1 uses spaced double friction discs 11 to improve heat dissipation. The connecting part is set as a petal-shaped structure including multiple fusion plates 24, and a portion of the fusion plate 24 is inserted between the two friction discs 11, which facilitates ventilation between the air duct between the two friction discs 11 and the center of the brake disc. The fusion plate 24 and the two friction discs 11 are metallurgically bonded to achieve a high-strength and high-reliability connection between the annular disc 1 and the connecting flange 2, while having minimal impact on the overall dimensional accuracy of the connecting flange 2. Metallurgical bonding means that the fusion plate 24 is cast integrally with the annular disc 1 as an insert during casting.

[0064] Based on the above embodiments, further, such as Figure 3 As shown, the inner diameter of the toothed ring 23 is the same as the inner diameter of the cylindrical body 21, and the outer diameter of the root of the fusion plate 24 is greater than or equal to the outer diameter of the toothed ring 23. That is, the wall thickness of the connecting part connected to the toothed ring 23 is greater than or equal to the width of the toothed ring 23, thereby providing better rigid support for the toothed ring 23 and making the toothed ring 23 less prone to deformation during use.

[0065] In some embodiments, the connecting flange 2 can be manufactured by a combination of spinning and machining processes. In this embodiment, the toothed connecting flange 2 no longer uses the cold stamping and flanging process, but can be directly formed using spinning technology. The body of the connecting flange 2 and the toothed ring 23 boss can be spun out at room temperature, which consumes less energy and produces a stronger connecting flange.

[0066] Specifically, such as Figures 4-10As shown, this application provides a method for manufacturing a bimetallic composite brake disc, including a method for manufacturing a connecting flange 2. The method for manufacturing the connecting flange 2 specifically includes the following steps: First, a circular disc blank 31 is provided. To reduce the stress on the equipment, the shape of the connecting disc 22 is initially formed by spinning to obtain a primary steel shell 32. Then, the primary steel shell 32 is placed in a mold for spinning. A groove 41 is set at the root of the mold 4 to leave enough material for the gear ring 23. The overall outline is first spun out using a coarse spinning wheel 42, and then finished using a fine spinning wheel 43 to obtain a formed steel shell 33 with a cylindrical main body 21 and a reserved gear ring material portion 331. The radius of the cutting tip of the coarse spinning wheel 42 is larger than the radius of the arc of the formed steel shell 33. When spinning to the bottom, some material enters the groove 41, but it may not fill the groove 41 completely. The larger radius of the arc leaves enough material to fill the groove 41. The precision spinning wheel 43 uses the same arc radius as the forming steel shell 33. When the precision spinning wheel 43 spins to the arc at the root of the forming steel shell 33, it uses slow spinning to reduce the speed, providing sufficient time for the material to flow into the groove 41. The slow spinning also helps to maintain pressure, making the pre-reserved toothed ring material in the groove 41 more compact. Next, as... Figure 9 As shown, the formed steel shell 33 is punched to form the connecting part (i.e., a petal-shaped structure including multiple fused plates 24). Finally, as... Figure 10 As shown, the tooth profile is machined on the reserved tooth ring material section 331 by methods such as gear hobbing, gear shaping, or milling. Among these methods, gear hobbing has a higher production efficiency.

[0067] Preferably, the material of the annular blank 31 can be 380CL or 420CL steel. 380CL and 420CL steel have good plasticity and moderate strength, which are very suitable for large deformation in spinning without cracking.

[0068] In addition, in some embodiments, the connecting flange 2 can also be manufactured using a hot stamping process. The connecting flange 2 of existing bimetallic composite brake discs is generally made of Q235 steel, with a yield strength ≥235MPa, tensile strength 375-500MPa, and elongation ≥26%. The manufacturing process involves flanging and stamping at room temperature to form the overall shape of the connecting flange 2. If a toothed ring 23 boss is provided on the connecting flange 2, integrating the toothed ring 23 and the flange into one unit, and flanging at room temperature, although Q235 has good plasticity, it is still impossible to guarantee a full boss or complete tooth profile. To ensure a full boss and complete tooth profile for the toothed ring 23 boss, the steel shell needs to be heated, and the stamping process should be performed while the steel shell is in an annealed state.

[0069] This application also provides another method for manufacturing a bimetallic composite brake disc, including a method for manufacturing a connecting flange 2, wherein the method for manufacturing the connecting flange 2 specifically includes the following steps: First, providing as follows Figure 4 and Figure 5The circular annular blank 31 is shown. Next, the outer region of the circular annular blank 31 is heated to above its recrystallization temperature. When steel is heated above its recrystallization temperature, atomic mobility increases, grain boundary slip is easier, the material becomes "softer," and its plasticity is significantly improved. This makes the metal easier to flow and deform during stamping, and less prone to cracking or fracture. Simultaneously, at high temperatures, the resistance to dislocation movement within the metal decreases, and the required external force is significantly reduced, allowing for the use of smaller tonnage equipment to complete large deformation processes, saving energy and reducing equipment costs. During stamping, the grains are refined; ultimately, a dense, uniform blank with excellent overall performance is obtained. The steel forms continuous fibrous flow lines in plastic flow, distributed along the steel shell contour, significantly improving its mechanical properties, especially impact resistance and fatigue strength. Then, with the connecting disc 22 end of the connecting flange 2 facing upwards, the heated circular annular blank 31 is stretched and stamped using a punch press to form the shape shown. Figure 9 The connecting flange blank 34 is shown. Finally, as... Figure 10 As shown, a toothed ring 23 is machined at the end of the connecting flange blank 34. That is, the manufactured connecting flange blank 34 is taken out, rotated 180°, so that the connecting plate 22 end of the connecting flange 2 faces downward, and the toothed ring 23 is pressed down from top to bottom.

[0070] When manufacturing the tooth profile of the gear ring 23, assuming it has 100 teeth, to reduce deformation and stamping resistance, the stamping is performed in two stages. In the first stamping, one tooth is stamped at a time, skipping one tooth. During stamping, space needs to be reserved for the material flow in the tooth grooves. The material flows from the tooth grooves to the tooth height, and the blank volume at the position of the ABS gear ring 23 needs to be accurately calculated. After casting the annular disc 1, during machining, the end face of the gear ring 23 needs to be machined to increase the runout of the end face of the gear ring 23 relative to the center line of the brake disc, ensuring the distance between the end face of the gear ring 23 and the surface of the connecting disc 22.

[0071] While brake discs offer significantly improved heat dissipation compared to brake drums, their performance remains less than ideal. The disc surface temperature remains high after braking, and the slow cooling rate negatively impacts braking performance. In particular, the large temperature difference between the outer and inner surfaces of the brake disc leads to greater thermal stress, resulting in earlier crack initiation and faster crack propagation. Changing the arrangement of the reinforcing ribs between the two disc surfaces can improve heat dissipation to some extent. For example, the ventilated brake disc and disc brake disclosed in Chinese Patent CN109578473B utilize linear reinforcing ribs to guide and direct cooling airflow. However, this does not allow the airflow within the duct to remain there for a sufficiently long time.

[0072] In view of this, in some embodiments, such as Figure 11As shown, a cast-formed connecting claw 12 is also provided between the two friction discs 11, which covers the outer wall of the fusion plate 24. The reinforcing ribs include multiple circumferentially distributed outer ribs 13 and multiple inner ribs 14. The outer ribs 13 are configured as oblique arc-shaped ribs (oblique meaning they have a certain inclination angle relative to the radial direction) and are located on the disc surface radially outside the connecting claw 12. Their cross-sectional width gradually increases from the outer end to the inner end, thus forming a diffuser-type airflow channel from the outside to the inside between two adjacent outer ribs 13. The inner ribs 14 are located on the disc surface between two adjacent connecting claws 12, and their cross-sectional width gradually increases from the inner end to the outer end, thus forming a diffuser-type airflow channel from the inside to the outside between the inner ribs 14 and the adjacent connecting claws 12.

[0073] During the rotation of this type of brake disc, airflow mainly occurs in two forms: 1. Under the action of centrifugal force, air flows from the center outwards. 2. Under the action of the oblique arc-shaped ribs, air flows from the outside towards the center. The oblique arc-shaped ribs, during rotation, act like fan blades, causing air to continuously flow from the outside of the blades towards the center of the brake disc.

[0074] In this embodiment, as Figure 12As shown, the airflow direction indicated by the arrow is formed inside the brake disc. To the right of the vertical center line of the brake disc, on the outer side of the brake disc, is a positive air pressure zone, where a large amount of air is transported into the air duct formed by the outer rib 13. At this time, the air pressure from the outside to the center is much greater than the centrifugal air pressure from the center to the outside, so overall, the airflow is from the outside to the center area. To the left of the vertical center line of the brake disc, i.e., behind the wheel, a negative air pressure zone is formed. Less air enters the center area from the air duct between the inner rib 14 and the adjacent connecting claw 12, while a large amount of air (air transported to the center area from the right side of the center line through the outer rib 13) gathers in the center area of ​​the brake disc, forming a large positive air pressure. The air in this area is transported to the outside by centrifugal force, and the centrifugal air pressure is much greater than the air pressure transported from the outside to the center area through the outer rib 13. Therefore, overall, the airflow is from the center area to the outside. This design effectively transfers the air pressure from the positive pressure zone in front of the wheel to the negative pressure zone behind the wheel via the brake disc, reducing the pressure difference between the front and rear of the wheel. This reduces pressure drag, wind resistance during driving, and overall vehicle drag, thus lowering fuel consumption. In this application, the specially shaped outer ribs 13 and inner ribs 14 create resistance when the air pressure from the positive pressure zone in front of the wheel enters the brake disc, causing the air to briefly linger or swirl within the air duct in the center of the disc, fully absorbing heat from the disc. Simultaneously, in the central area of ​​the brake disc, as airflow enters the disc's air duct under centrifugal force and then flows out to the negative pressure zone behind the wheel, the shape of the inner ribs 14 also provides resistance, causing the air to briefly linger or swirl within the air duct in the center of the disc, further absorbing heat from the disc. This results in a 35% increase in the temperature uniformity of the brake disc friction surface and a reduction in thermal warpage of more than 0.15 mm. Consequently, the outer and inner surfaces of the brake disc are kept at essentially the same temperature. (Existing brake disc structures typically have a lower temperature on the outer side of the annular disc body 1 and a higher temperature on the inner side of the disc body 1.) This effectively prevents the generation of large thermal stress due to the temperature difference between the inner and outer sides of the annular disc body 1. During braking, this reduces the generation and propagation of cracks, which helps to extend the service life of the brake disc.

[0075] More specifically, such as Figure 11 As shown, the width of the inner end of the inner rib 14 is d1, and the width of the outer end is d2; the width of the inner end of the outer rib 13 is d3, and the width of the outer end is d4. By changing the dimensions and width of the inner and outer ends of the ribs, the size of the air duct can be adjusted. When the ratio between them satisfies: d1:d2:d3:d4=1:(1.7-1.8):(1.7-1.8):1.3, the cross-sectional area ratio of the air duct can achieve a better heat dissipation effect.

[0076] In some embodiments, such as Figure 13As shown, on the opposing surfaces of the two friction discs 11, the inner disc surface has an inclined angle that widens towards the center, while the outer disc surface has an inclined angle that widens towards the edge. Both inclined angles can be set to 2°, thus making both the inner and outer sides of the brake disc body flared outwards, further increasing the air intake channel. Similarly, it further creates a small airflow obstruction in the middle, thereby further improving heat dissipation performance.

[0077] In some embodiments, such as Figure 11 As shown, on the surface of the opposite side of the two friction discs 11, there are also micro-diamond-shaped airflow guide ribs 15. The height of the micro-diamond-shaped airflow guide ribs 15 is 3mm. Micro-air channels 16 are formed between adjacent micro-diamond-shaped airflow guide ribs. The extension direction of the micro-air channels 16 is basically consistent with the extension direction of the outer ribs 13 and the inner ribs 14. The micro-diamond-shaped airflow guide ribs 15 can disturb the airflow in the air channel, break the low-speed boundary layer that is originally close to the inner wall of the disc, and allow the cooler airflow to directly contact the warmer inner wall of the disc, thereby enhancing local heat exchange and avoiding excessive temperature difference between the inner and outer rings of the friction disc 11 caused by excessively high local temperature of the brake disc. This avoids large temperature stress between the inner and outer rings of the friction disc 11, and thus avoids warping deformation or umbrella-shaped deformation of the brake disc.

[0078] The opposing surfaces of the two friction discs 11 are designed with miniature diamond-shaped airflow guide ribs 15, which increases the surface area of ​​the brake disc in contact with the air and improves the specific surface area of ​​the brake disc body. The surface area is increased by 40%-50%, which can effectively dissipate the heat inside the disc body. At the same time, the weight of the disc body is further reduced, which can further reduce weight.

[0079] In summary, the bimetallic composite brake disc provided in this embodiment employs a structure combining special ribs and micro-guide ribs, achieving low resistance, high heat dissipation, and lightweight design. Our verification shows that the brake disc weight is reduced by 5%-8%, and heat dissipation efficiency is improved by over 25%.

[0080] Preferably, in some embodiments, the entire surface of the air duct formed between the two friction discs 11 can be coated with a high silicon aluminum alloy layer with a coating thickness of 0.03-0.05mm, so that the surface of the air duct has a high heat dissipation coefficient and a large heat dissipation area, which can quickly transfer the heat of the friction discs 11 to the air duct and be carried away by the wind.

[0081] Currently, most brake discs on the market, whether gray cast iron or steel composite, are made of gray cast iron. During their lifespan, they experience severe wear, with approximately 2mm of wear on one side and about 4mm on the entire disc surface, generating a large amount of shavings and iron powder, causing serious environmental pollution. Furthermore, as described below, some discs show severe wear on the flanged side while the side away from the flange wears less. In other words, one side of the disc reaches the end-of-life standard, while the other side does not, but for safety reasons, the brake disc still needs to be replaced, resulting in significant waste. According to after-sales data, over 60% of brake discs fail first on the flanged side, while the side without the flange has not yet reached the failure standard. However, for safety reasons, the brake disc still needs to be replaced (even though it hasn't reached the failure standard, replacement is still necessary).

[0082] In view of this, in some embodiments, such as Figure 14 As shown, the transverse centerline 17 of the air duct formed between the two friction discs 11 is set to be offset away from the connecting disc 22 relative to the transverse centerline 18 of the annular disc body, with an eccentricity of 1-3 mm.

[0083] During braking, the braking torque, radial force, and lateral force applied by the brake pads are all transmitted to the wheel hub through the connecting flange 2. The friction disc 11 surface near the connecting flange 2 is the area of ​​torque input and stress concentration, so the friction disc 11 surface on this side wears faster and cracks appear earlier. The non-flange side is the free end, with slightly greater structural flexibility and more dispersed stress distribution. Under the same braking intensity, the material on the flange side bears higher cyclic stress and contact compressive stress, resulting in a naturally higher friction and wear rate. In this embodiment, the two friction discs 11 of the annular disc body 1 are set as an asymmetrical structure, which can effectively improve the rigidity of the friction disc 11 on the flange side, reduce excessive wear on the friction disc 11 surface on this side, and achieve simultaneous failure of both friction discs 11 surfaces, effectively extending the service life of the brake disc and reducing the waste of the friction disc 11 on the non-flange side.

[0084] Single-layer gray cast iron brake discs are typically made of HT200. For steel composite brake discs, the flanges and connecting discs (22) are generally made of Q235, Q355, or ZG230, while the disc body is made of HT200, primarily utilizing the wear-resistant properties of gray cast iron HT200. However, the wear-resistant layer of gray cast iron generates a large amount of wear debris during braking, polluting the environment and affecting human health.

[0085] In view of this, in some embodiments, such as Figure 15As shown, the annular disk 1 includes a high-strength structural layer 101 in the middle and long-term wear-resistant layers 102 covering its two end faces. The high-strength structural layer 101 is made of HT250 or ductile iron grades such as QT450 and QT500. The long-term wear-resistant layer 102 is made of a nickel-based self-fluxing alloy as the matrix, which is composite with WC, TiC and Mixed hard phase particles, with trace amounts added and Rare earth oxides.

[0086] The annular disc 1 is divided into a high-strength structural layer 101 and a long-lasting wear-resistant layer. With the support of the high-strength structural layer 101, the overall strength and rigidity of the high-strength structural layer 101 are high. As the basic load-bearing layer, the brake disc exhibits minimal umbrella-shaped deformation during braking, resulting in a long service life. This application adds a long-lasting wear-resistant layer 102 made of a special material: high hardness and good wear resistance, further extending the service life of the brake disc. It also reduces the amount of wear debris and dust generated during braking, minimizing environmental pollution and harm to human health.

[0087] Specifically, the composition of the nickel-based self-fluxing alloy is as follows:

[0088] Ni: Balance; Cr: 16–22%; B: 2.5–4.0%; Si: 3.0–5.0%; C: 0.4–0.8%; Mo: 2.0–4.0%; W: 1.5–3.0%. Ni's role: base material, ensuring toughness, wettability, and crack resistance; Cr's role: oxidation resistance, high-temperature corrosion resistance, and improved red hardness; B's role: self-fluidization, lowering melting point, and strengthening grain boundaries; Si's role: deoxidation, improving fluidity, and forming hard silicides; C's role: forming carbides, increasing hardness and wear resistance; Mo's role: solid solution strengthening, improving high-temperature strength, and resisting thermal fatigue; W's role: improving red hardness and enhancing high-temperature wear resistance.

[0089] In nickel-based alloy powder, composite hard phase particles are added externally (total added proportion: 18–30%), specifically as follows: +Rare earth oxides. Among them,

[0090] 1. WC (micron-level, 45–75 μm): 10–18%. Function: Main wear-resistant phase, improves dry friction and wear performance.

[0091] 2. TiC (nano / submicron): 3–6%. Functions: Refines grain size, disperses and strengthens, and improves high-temperature stability.

[0092] 3. : 2–4%. Function: To supplement high-temperature wear resistance and oxidation resistance, and to form eutectic reinforcement with the matrix.

[0093] 4. Small amounts of rare earth oxides ( (Composite): 0.3–1.0%. Function: Purifies grain boundaries, reduces porosity and cracks, and improves the bonding between the coating and the substrate.

[0094] The final composition of the nickel-based self-fluxing alloy after the addition of hard phases and rare earth oxides is as follows: Cr: 18–24%; B: 2.0–3.5%; Si: 2.5–4.5%; C: 0.5–1.0%; Mo: 2.0–3.5%; W: 1.2–2.5%; WC: 10–18%; TiC: 3–6%. 2–4%; : 0.3–1.0%; the remainder is Ni.

[0095] A comparative experiment was conducted on the material of the long-term wear layer 102 in this embodiment. The experimental substrate material was a commercial vehicle brake disc, ductile iron QT450-10. Specific experimental data are as follows:

[0096] This invention: Ni-based + WC + TiC + +Rare earth composite coating;

[0097] Comparative Test 1: Conventional commercial Ni60 alloy coating (no multi-component hard phase, no rare earth elements);

[0098] Comparative Experiment 2: Ni-based + single WC coating (without TiC, (rare earth elements)

[0099] Comparative Experiment 3: Ni-based + WC + TiC + (Rare earth-free composite coating);

[0100] Comparative Experiment 4: Ni-based + WC + TiC + +Yttrium oxide (single rare earth element, not composite rare earth element).

[0101] The specific experimental results are shown in the table below:

[0102] .

[0103] The hardness tests in the table above were conducted using an HV-1000 microhardness tester, according to GB / T1172-1999 "Conversion Values ​​of Hardness and Strength for Ferrous Metals" standard; the test load was 0.2 kgf. The load holding time was 15s; 10 test points were evenly selected on the cross-section of the coating for each sample (avoiding defect areas), and the average value was taken as the average microhardness of the coating after the test was completed, while the hardness fluctuation range was recorded.

[0104] The bonding strength test was conducted using a WDW-300 electronic universal testing machine, following the GB / T8642-2002 standard "Determination of Bond Strength of Thermal Spray Coatings", employing the tensile shear method. The coating sample and the substrate sample were fixed together using a special fixture, and an axial tensile load was applied until the coating separated from the substrate. The maximum load at fracture was recorded, along with the stress area of ​​the bonding sample, to calculate the bonding strength between the coating and the substrate. Five parallel samples were selected from each group, and the average value was taken as the average bonding strength of that group.

[0105] Dry friction and wear performance testing was conducted using a UMT-3 friction and wear testing machine, following the GB / T12444-2016 standard "Metallic Materials - Test Methods for Wear". The test conditions simulated the actual service conditions of a brake disc: load 300 N, linear velocity 1.5 m / s, dry friction environment, and test time 30 min. The wear pair was made of GCr15 bearing steel (hardness 62~65 HRC). After the test, a micrometer with an accuracy of 0.001 mm was used to measure the dimensional changes of the sample before and after wear, and the wear volume was calculated. Simultaneously, the change in the coefficient of friction during the test was recorded, and the average value was taken as the average coefficient of friction for the sample to analyze frictional stability.

[0106] Dry friction and wear tests were conducted under different high-temperature environments (25℃, 400℃, and 600℃). The test conditions were: load 300N, linear velocity 1.5m / s, and test time 10min. The average friction coefficient at different temperatures was recorded, and the frictional stability and thermal decay phenomenon of the coating under high-temperature conditions were analyzed. The degree of thermal decay was measured by the difference in friction coefficient between 600℃ and 25℃; the smaller the difference, the weaker the thermal decay.

[0107] Thermal fatigue performance testing was conducted using an 8000-type brake performance test bench, simulating the actual service conditions of the brake disc. The initial braking speed was 85 km / h, the braking termination speed was 50 km / h, the brake air pressure was 0.2 MPa, and the initial braking temperature was 50℃. During the bench test, the brake disc was deemed to have failed if any of the following phenomena were observed.

[0108] a) The specified or required number of cycles were completed without failure:

[0109] b) When a radial crack (regardless of its width or depth) runs radially and its length is 75% or more of the width of the rotor braking surface;

[0110] c) Radial cracks are visible on both sides of the friction surface on the outer or inner diameter of the rotor braking surface. This is also known as "through-crack".

[0111] d) Cracks originating from or between mounting holes;

[0112] e) Structural integrity failures do not allow the generation of braking torque in subsequent cycles.

[0113] f) The thickness of the friction material reaches the shutdown limit specified in 10.4.

[0114] Three parallel samples were selected for each group, and the average value was taken as the average failure cycle number for that group.

[0115] Defect detection of the coating was performed using a DM2500M metallographic microscope and an EVO18 scanning electron microscope (SEM) to observe the microstructure and defects of the coating. Porosity was calculated using image analysis. Three different fields of view (each field of view area 1 mm²) were selected on the coating cross-section, and the proportion of pore area to the total field of view area was measured. The average value was taken as the porosity of the coating. Cracks were observed under a microscope, and the presence, number, and distribution of macro-cracks and micro-cracks in the coating were recorded.

[0116] Based on the experimental data above, it can be seen that the bimetallic composite brake disc provided in this embodiment can effectively solve the problem of thermal fade and high-temperature friction caused by local high temperatures (400–600℃) during brake braking, thus delaying the initiation and propagation of cracks and increasing the number of thermal fatigue cycles. Meanwhile, ordinary gray cast iron discs generate iron powder and abrasive shavings during braking, which become trapped between the disc surface and the brake pads, acting as an abrasive and accelerating brake disc wear. Conventional coatings also suffer from problems such as easy cracking and poor adhesion. The long-lasting wear layer 102 in this embodiment has strong adhesion and does not crack.

[0117] Preferably, the long-lasting wear layer 102 is formed on the high-strength structural layer 101 by laser cladding. This long-lasting wear layer 102, formed on the high-strength structural layer 101 by laser cladding, possesses high-temperature wear resistance, thermal fatigue resistance, and low crack sensitivity. The specific process of laser cladding spraying is as follows:

[0118] ① The surface of the disc must be free of oil. If oil gets on it during hoisting, it must be cleaned with alcohol before applying the long-lasting wear-resistant layer. Preheat the disc to 150-200℃ before spraying. Oil contamination will prevent metallurgical bonding. Insufficient preheating will cause the coating to crack.

[0119] ② The material of the above-mentioned long-lasting wear layer 102 is made into powder.

[0120] ③ The focused laser beam irradiates the surface of the brake disc, causing the surface layer to slightly melt. Simultaneously, alloy powder is sprayed onto the surface of the disc. The sprayed alloy powder is heated by the laser and completely melts, forming a tiny, high-temperature molten pool on the brake disc surface. Within the molten pool, the alloy material and the surface metal of the brake disc rapidly convection and diffuse, resulting in a metallurgical bond.

[0121] ④ The nozzle moves radially, and the brake disc can rotate on the equipment at the same time. This completes the spraying of the entire disc surface.

[0122] ⑤ After spraying, the surface needs to be annealed at a low temperature. Heat to 180-220℃, hold for 2-3 hours, cool in the furnace to below 100℃, and then air cool. This removes the internal stress generated by rapid solidification and thermal cycling, preventing cracking and deformation. It does not aim for precipitation strengthening, but only stress release. The entire process is carried out at a low temperature, and slow cooling is required after holding the heat.

[0123] The coating thickness is 0.3-0.5mm; it is completed in one spraying. Production efficiency is high. Laser power is 2-4KW, and powder feeding rate is 25-40g / min.

[0124] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0125] The mechanism provided by this invention has been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the embodiments above are merely for the purpose of helping to understand the method and core ideas of this invention. It should be noted that those skilled in the art can make various improvements and modifications to this invention without departing from its principles, and these improvements and modifications also fall within the protection scope of the claims of this invention. Therefore, this invention is not limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A bimetallic composite brake disc, characterized in that, It includes an annular disc (1) and a connecting flange (2). The connecting flange (2) includes a cylindrical body (21). The first end of the cylindrical body (21) is provided with a connecting disc (22) integrally connected to the cylindrical body (21). The second end is provided with a toothed ring (23) integrally connected to the cylindrical body (21). The outer peripheral surface of the cylindrical body (21) near the second end is provided with an outwardly extending connecting part. The connecting part is fixedly connected to the inner ring of the annular disc (1).

2. The bimetallic composite brake disc according to claim 1, characterized in that, The tooth width of the toothed ring (23) is greater than the wall thickness of the cylindrical body (21).

3. The bimetallic composite brake disc according to claim 1, characterized in that, The connecting part includes a plurality of fusion plates (24) evenly distributed on the outer circumferential surface of the cylindrical body (21). The annular disc (1) includes two friction discs (11) spaced apart and a reinforcing rib connected between the two friction discs (11). A portion of the fusion plate (24) is inserted between the two friction discs (11) and is metallurgically joined to one side of the two friction discs (11) facing each other.

4. The bimetallic composite brake disc according to claim 3, characterized in that, The inner diameter of the toothed ring (23) is the same as the inner diameter of the cylindrical body (21), and the outer diameter of the root of the fusion plate (24) is the same as the outer diameter of the toothed ring (23).

5. The bimetallic composite brake disc according to any one of claims 1-4, characterized in that, The connecting flange (2) is made by spinning and machining processes.

6. The bimetallic composite brake disc according to any one of claims 1-4, characterized in that, The connecting flange (2) is made by a hot stamping process.

7. The bimetallic composite brake disc according to claim 3, characterized in that, A casting-molded connecting claw (12) is provided between the two friction discs (11). The connecting claw (12) covers the outer wall of the fusion plate (24). The reinforcing ribs include a plurality of circumferentially distributed outer ribs (13) and a plurality of inner ribs (14). The outer rib (13) is set as an oblique arc rib and is located on the disk surface on the radial outer side of the connecting claw (12). Its cross-sectional width gradually increases from the outer end to the inner end, so that a diffuser air duct is formed between two adjacent outer ribs (13) from the outside to the inside. The inner rib (14) is located on the disk surface between two adjacent connecting claws (12), and its cross-sectional width gradually increases from the inner end to the outer end, so that the inner rib (14) and the adjacent connecting claws (12) form a diffuser air duct from the inside to the outside.

8. The bimetallic composite brake disc according to claim 7, characterized in that, The width of the inner end of the inner rib (14) is d1 and the width of the outer end is d2. The width of the inner end of the outer rib (13) is d3 and the width of the outer end is d4, which satisfies: d1:d2:d3:d4=1:(1.7-1.8):(1.7-1.8):1.

3.

9. The bimetallic composite brake disc according to claim 7, characterized in that, Of the two friction discs (11) facing each other, the inner disc has an inclined angle that widens towards the center, and the outer disc has an inclined angle that widens towards the outer edge.

10. The bimetallic composite brake disc according to claim 7, characterized in that, The surfaces of the two friction discs (11) on opposite sides are provided with micro-diamond-shaped airflow guide ribs (15), and micro-air ducts (16) are formed between adjacent micro-diamond-shaped airflow guide ribs (15) with the extension direction being consistent with the extension direction of the outer ribs (13) and inner ribs (14).

11. The bimetallic composite brake disc according to claim 7, characterized in that, The surface of the air duct formed between the two friction discs (11) is coated with a high-silicon aluminum alloy layer.

12. The bimetallic composite brake disc according to claim 3, characterized in that, The transverse centerline (17) of the air duct formed between the two friction discs (11) is offset away from the transverse centerline (18) of the annular disc in a direction away from the connecting disc (22).

13. The bimetallic composite brake disc according to claim 1, characterized in that, The annular disk (1) includes a high-strength structural layer (101) in the middle and long-term wear-resistant layers (102) covering its two end faces. The long-term wear-resistant layers (102) are made of a nickel-based self-fluxing alloy as the matrix, which is compounded with WC, TiC and Mixed hard phase particles, and added and Rare earth oxides.

14. The bimetallic composite brake disc according to claim 13, characterized in that, The long-lasting wear layer (102) is formed on the high-strength structural layer (101) by laser cladding process.

15. A method for manufacturing a bimetallic composite brake disc, characterized in that, The method for manufacturing a connecting flange (2) includes the following steps: Step 1: Provide a circular disc blank (31), and form the shape of the connecting disc (22) by spinning process to obtain the primary steel shell (32). Step 2: Place the primary steel shell (32) in the mold (4) for spinning. Set a groove (41) at the root of the mold (4). First, use a coarse spinning wheel (42) to spin out the overall outline, and then use a fine spinning wheel (43) to finish it, so as to obtain a shaped steel shell (33) with a cylindrical body (21) and a reserved toothed ring material part (331). The radius of the blade tip of the coarse spinning wheel (42) is larger than the radius of the arc of the shaped steel shell (33). Step 3: Punch the formed steel shell (33) to form the connecting part; Step 4: Machining tooth profiles on the reserved toothed ring material (331) to form a toothed ring (23).

16. The method for manufacturing a bimetallic composite brake disc according to claim 15, characterized in that, The material of the circular disc blank (31) is 380CL or 420CL steel.

17. A method for manufacturing a bimetallic composite brake disc, characterized in that, The method for manufacturing a connecting flange (2) includes the following steps: Step 1: Provide the circular dough (31); Step 2: Heat the outer ring region of the circular disc blank (31) to above the recrystallization temperature; Step 3: Stretch and press the heated blank to form a connecting flange blank (34). Step 4: Machining a toothed ring (23) at the end of the blank.

Images