Bimetal brake drum with pre-embedded steel mesh
By embedding the steel mesh structure in the bimetal brake drum, the problems of poor resistance to deformation and interface defects of the bimetal brake drum are solved, and higher resistance to deformation and heat dissipation are achieved, while reducing costs and thickness and extending service life.
Patent Information
- Application Number
- CN202422062670.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-23
- Publication Date
- 2025-05-13
- Estimated Expiration
- 2034-08-23
AI Technical Summary
The existing bimetallic brake drum has poor resistance to deformation, interface defects affect the heat dissipation effect and have stress problems, resulting in damage to the brake drum structure and high cost.
The bimetal braking drum structure of the embedded steel mesh is adopted. The steel mesh replaces the steel shell. The cast iron friction layer is cast into the steel mesh mesh hole. The steel mesh and the steel excessive part are connected by welding to form an annular structure to improve the overall strength and deformation resistance.
It effectively overcomes the interface problem of the bimetallic brake drum, improves the deformation resistance and heat dissipation effect of the brake drum, reduces the material cost and brake drum thickness, and extends the service life.
Smart Images
Figure CN222863944U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to a bimetallic brake drum for an automobile, in particular to a bimetallic composite brake drum with a pre-embedded steel mesh. Background Art
[0002] In the prior art, trucks generally use drum brake systems. The original automobile brake drums were cast with gray cast iron. Since gray cast iron is a friction material with better performance, gray cast iron brake drums once occupied the main market of automobile brake drums. However, gray cast iron brake drums have obvious defects, such as loose molecular arrangement during casting, low strength of gray cast iron itself, good rigidity but poor toughness, and easy to burn, tear, and damage. In order to maintain the shape stability and structure of the gray cast iron brake drum, the brake drum needs to be made very thick, resulting in a large weight. Heavy weight, low strength, and poor metallographic structure are defects that cannot be overcome by the casting process of the gray cast iron brake drum itself.
[0003] Later, people developed a bimetallic brake drum, which basically achieved the purpose of lightweight and reduced the weight and thickness of the brake drum. It uses a steel outer shell layer to ensure mechanical strength, and uses gray cast iron as the friction layer for friction braking in the inner layer to achieve the above purpose. Since the mechanical strength of steel is much higher than that of cast iron, the overall drum thickness can be reduced, thereby reducing the weight. The inner and outer layers of the bimetallic brake drum have also undergone a transition from mechanical bonding to metallurgical casting bonding. The current bimetallic brake drum generally adopts the form of casting bonding, which consists of a brake drum outer shell layer and a friction layer. The friction layer is cast and bonded to the inside of the outer shell. The outer shell is a steel shell, which can reduce the thickness, reduce the weight and increase the strength. The flange end of the outer shell is provided with bolt holes and a center hole. Since the inner cast iron layer is cast inside the outer shell, and the outer shell is formed by spinning of the steel plate, the molecular structure is arranged more closely, and the overall thickness and weight of the brake drum are greatly reduced. At the same time, the mechanical strength of the overall brake drum can be improved, and the occurrence of thermal cracking and tearing can be effectively avoided.
[0004] However, as the weight and thickness of the bimetallic brake drum decrease and the performance improves, the cost of the above-mentioned brake drum also increases, and some other properties are also sacrificed. For example, although the cast iron brake drum uses a large amount of materials, the material price is low, there are fewer processing steps, and the material cost and processing cost are relatively low. The bimetallic brake drum has high material cost and high processing cost. Since the friction layer is centrifugally cast into the outer shell layer, a bimetallic metallurgical bonding interface will be formed during casting. Due to the existence of the interface, the heat dissipation effect of the brake drum will be affected. There are also serious stress problems at the bonding interface, such as unstable and unbalanced stress, which can easily cause the structure of the brake drum itself to be damaged due to stress. In addition, because the outer shell layer is made of steel, although the strength is improved, the deformation resistance is poor. When the brake drum is working, when the temperature rises, it is easy to cause the shape of the brake drum to change, affecting the braking effect.
[0005] In view of the above reasons, the designers have designed a bimetallic brake drum with a new structure, which overcomes the defects of the existing bimetallic brake drum and the defects of the cast iron brake drum, and can balance various performances well. Utility Model Content
[0006] The utility model aims to provide a bimetallic brake drum with a pre-embedded steel mesh, which can effectively solve the defect of poor anti-deformation ability of the bimetallic brake drum, overcome the interface defects of the bimetallic brake drum, and reduce the manufacturing cost of the bimetallic brake drum.
[0007] The utility model of the bimetal brake drum with embedded steel mesh comprises a steel material part and a cast iron friction part. The steel material part comprises an embedded steel mesh outside the drum tube part, a steel flange part and a steel transition part, wherein the steel transition part is connected between the embedded steel mesh and the steel flange part; the cast iron friction part is cast and combined with the drum tube part, and part of the cast iron material of the cast iron friction part is cast into the mesh of the embedded steel mesh outside the drum tube part.
[0008] In the bimetallic brake drum with embedded steel mesh described above, the steel flange part and the steel transition part are annular structures, which are made by integrally stamping steel plate materials, and the embedded steel mesh on the outer side of the drum tube part is a cylindrical steel mesh, which is made by stamping steel plates or weaving steel wire materials.
[0009] In the bimetallic brake drum with embedded steel mesh described above, the connection structure between the embedded steel mesh on the outer side of the brake drum tube and the steel transition part is a welded connection structure or an integral stamping structure.
[0010] In the bimetallic brake drum with embedded steel mesh described above, the embedded steel mesh on the outer side of the drum tube is annularly welded to the steel transition portion, and the casting area of the cast iron friction portion covers the welded connection ring between the embedded steel mesh and the transition portion.
[0011] In the bimetallic brake drum with embedded steel mesh described above, the mesh of the embedded steel mesh on the outer side of the drum tube is square or diamond-shaped, the mesh size is between 10*10 mm and 30*30 mm, the cross section of the steel mesh wire is square, the size is not less than 5*5 mm. The cross section of the steel mesh wire can also be circular, and the diameter of the wire size is not less than 5 mm.
[0012] In the bimetallic brake drum with embedded steel mesh described above, the mesh size of the embedded steel mesh on the outer side of the drum tube gradually decreases from the proximal end of the flange to the distal end of the flange. Alternatively, the mesh wire size of the embedded steel mesh on the outer side of the drum tube gradually increases from the proximal end of the flange to the distal end of the flange.
[0013] The bimetallic brake drum of the utility model replaces the steel shell with a steel mesh, and the steel mesh can be fully covered by casting or centrifugal casting of gray cast iron. Then the cast iron part can enter the mesh, which can improve the strength and maintain the anti-deformation ability of cast iron, and overcome the influence of the casting interface of the bimetallic brake drum, which is specifically manifested as follows:
[0014] 1. The bimetallic brake drum of the utility model replaces the cylindrical steel shell with a steel mesh. In fact, the cast steel reinforcement ribs are embedded on the outside of the cast iron brake drum, thus avoiding the defect of easy tearing of pure cast iron materials and achieving the effect of a steel shell brake drum. However, compared with the steel cylindrical shell brake drum, the utility model structure can reduce the steel consumption by more than one third, effectively reducing the material cost.
[0015] 2. Since the steel mesh is set as the embedded reinforcement rib to increase the strength of the overall brake drum, the thickness of the cast iron can be greatly reduced. The cast iron is cast into the mesh. Compared with the steel cylindrical shell bimetallic brake drum, the cast iron of the embedded steel mesh part can still be used as a friction layer, thereby increasing the thickness of the friction layer and extending the service life of the brake drum.
[0016] 3. The pre-buried steel mesh wire is quickly heated up in the high temperature wrapping of cast iron during casting, reaching the surface molten state, which is conducive to achieving metallurgical bonding and improving the reliability of bonding. This is also something that cannot be achieved by the annular casting contact of the steel cylindrical shell.
[0017] 4. The interface area between the steel mesh wire and the cast iron casting is small. The gray cast iron penetrates all the way to the outer surface of the brake drum at the mesh holes. The material consistency is good and no interface is formed here. The heat dissipation effect will not be affected by the existence of the interface.
[0018] 5. It is helpful to eliminate interface stress and avoid damage to the brake drum itself caused by interface stress.
[0019] 6. The embedded steel mesh brake drum of the utility model structure has a large proportion of cast iron and the mesh holes penetrate the inside and outside of the brake drum, thus effectively overcoming the problem of thermal deformation caused by the outer shell of the steel material.
[0020] 7. The embedded steel mesh is used as a reinforcing rib in the utility model product, which can reduce the thickness of the brake drum. The thickness of the thickest part of the brake drum of the utility model can be reduced to less than 20 mm, and the weight can be greatly reduced. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1 It is a schematic diagram of the cross-sectional structure of the bimetallic brake drum of the utility model;
[0022] Figure 2 It is a schematic diagram of the cross-sectional structure of the steel material portion of the bimetallic brake drum of the utility model;
[0023] Figure 3 It is a schematic diagram of the cross-sectional structure of the centrifugal casting mold of the utility model. DETAILED DESCRIPTION
[0024] The bimetallic brake drum and the manufacturing method thereof of the present invention are described in detail below in conjunction with the accompanying drawings and specific embodiments. The specific drawings and embodiments are only used for illustration and are not used to limit the scope of protection.
[0025] Embodiment 1: The structure of the bimetallic brake drum of this embodiment is as follows Figure 1 , Figure 2 shown.
[0026] The bimetallic brake drum of this embodiment is composed of two parts, namely, a steel material part and a gray cast iron friction part 5. The steel material part is composed of three parts, namely, a steel plate flange part 1, a steel plate transition part 2 and a pre-embedded steel mesh drum part 4. The steel plate flange part 1 and the steel plate transition part 2 are integrally stamped from steel plate materials, and the pre-embedded steel mesh drum part 4 is made of a steel mesh stamped from steel plate materials. The pre-embedded steel mesh drum part 4 is fixedly connected to the steel plate transition part 2 by a circular weld seam 3.
[0027] The gray cast iron friction part 5 is a friction layer cast at the embedded steel mesh drum part 4 of the steel material part. Due to the presence of the embedded steel mesh drum part 4, the gray cast iron can be cast into the mesh 41 of the steel mesh at the embedded steel mesh drum part 4, and at the same time, the gray cast iron friction part 5 wraps the mesh wire 42 of the steel mesh from at least three sides.
[0028] In the structure of the above embodiment, the pre-buried steel mesh drum tube 4 is located at the outermost side of the brake drum, and is used as a steel reinforcement rib of the gray cast iron friction part 5 to improve the tensile strength, and can avoid the pure gray cast iron brake drum from being damaged by heat and tearing. The gray cast iron in the brake drum occupies most of the brake drum space, so its deformation resistance is almost the same as that of the gray cast iron, and the defect of easy deformation of the brake drum due to the use of steel materials will not be caused. The molten interface between the steel mesh and the gray cast iron of the brake drum is located on the side close to the brake drum shell, so the thickness of the gray cast iron can be appropriately increased, the friction consumption time can be extended, and the service life can be extended. The thickness of the brake drum can be appropriately reduced. For example, the thickest part of the steel shell bimetallic brake drum often reaches 30-40 mm, and the brake drum using this structure can be reduced to less than 20 mm.
[0029] Specifically, the mesh of the embedded steel mesh can be square or diamond-shaped, and the mesh size should be controlled to be above 10*10 mm, and below 30*30 mm for better results. Too large meshes will lead to insufficient improvement in tensile strength, and too small meshes will lead to poor anti-deformation ability. This size setting is only a principle setting, which is suitable for brake drums of common specifications, but the mesh size can be specifically set according to different specifications and different needs, and cannot be generalized.
[0030] The wire of the embedded steel mesh generally needs to be set with a certain cross-sectional area requirement. For example, for the steel mesh of steel plate stamping, the cross-section of the wire is generally square or diamond, preferably not less than 5*5 mm. If the steel mesh is made of woven steel wire, the cross-section can be circular, and the diameter of the circular cross-section is preferably not less than 5 mm. However, this size generally does not need to be strictly limited, because the wire size is to ensure that the tensile properties of the steel are still maintained after casting cast iron, and it is necessary not to melt all of it during casting, so the size cannot be too small, but it can be specifically set according to different specifications and different uses.
[0031] The mesh sizes of the steel mesh may also be different. In view of the existence of the steel plate transition portion 2 and the steel plate flange portion 1 at the flange end, the strength is sufficient, so the mesh size can be set to different sizes according to the distance from the flange end. For example, the mesh size at the proximal end of the flange can be larger, and the mesh size at the distal end of the flange can be relatively small, or it can be in a gradual size change state.
[0032] Similarly, the size of the steel mesh wire can also be a state where the wire size at the far end of the flange is larger and the wire size at the near end of the flange is smaller.
[0033] The product of the above fact is made like this:
[0034] First, the steel material part should be made according to the specifications of the brake drum. The steel material part includes the steel plate flange part 1, the steel plate transition part 2 and the embedded steel mesh drum part 4. The steel flange part 1 and the steel plate transition part 2 are formed by integral stamping. The steel plate is cut into a circular ring structure, that is, it is cut into a circular plate, and then the center hole of the flange part is cut in the center. Then the stamping machine is used to stamp out the structure of the flange part 1 and the transition part 2 from the circular ring.
[0035] Next, the embedded steel mesh drum tube part 4 is made. The embedded steel mesh drum tube part 4 of this embodiment is made of 5 mm thick steel plate, which is formed into a rectangular sheet steel mesh by stamping and cutting. The steel mesh mesh 41 is a square mesh with a mesh size of 30*30 mm. The embedded steel mesh wire 42 obtained by stamping is a square cross-section, and the wire 42 size is 5*5 mm. After the sheet steel mesh is formed, the sheet steel mesh is rolled and welded into a circular steel mesh cylinder. Then, according to the shape of the outer edge of the brake drum, the steel mesh cylinder is stamped to form a structure corresponding to the shape of the outer edge of the brake drum. Then, the cylindrical steel mesh is annularly welded to the end of the transition part 2 to form a complete brake drum steel material part. The welding point of the annular welding should be within the casting area of the gray cast iron casting, and the welding point should be covered with the gray cast iron casting to ensure that the welding is firm.
[0036] Making a casting mold: In this embodiment, the brake drum can be cast in cast iron by centrifugal casting. Centrifugal casting requires making a special mold, such as Figure 3 As shown, the mold is made in the form of iron film coated sand inside a cylindrical metal outer mold 6. The mold coated sand mold 7 has a shape corresponding to the outer edge of the brake drum. After the iron film coated sand mold is made, the integral steel material part is fixed in the mold, close to the inner side of the iron film coated sand mold 7. The metal outer mold 6 and the coated sand mold 7 are both provided with an upper mold and a lower mold structure that are butt-jointed at the bottom of a mountain, so that the mold is easy to assemble and disassemble when casting a brake drum with a wavy outer edge.
[0037] After the centrifugal casting mold and the steel material part are fixed, the cylindrical metal outer mold 6 is locked and set on the centrifugal casting machine, and the mold 6 drives the steel material part to rotate horizontally. During the horizontal rotation process, the electromagnetic coil can be extended to heat the steel mesh part. After maintaining a certain heating temperature, the cast iron material is cast.
[0038] After the casting is completed, the mold is removed from the centrifuge and demolded after cooling to obtain the brake drum casting blank, which can then be made into a finished brake drum after fine processing.
[0039] During casting, the centrifugal speed can be controlled at 570-890 per minute. It can be calculated according to the empirical formula without strict restrictions. The heating temperature of the steel mesh can be 500-800 degrees Celsius. Because it is a steel mesh, it is easier to melt during casting, so the temperature can be lower. The casting temperature of gray cast iron can be controlled at a general temperature, such as 1430-1570 degrees Celsius, which can be verified by experiments.
[0040] If the above centrifugal casting method is used, continuous production on an assembly line can be achieved, thereby improving production efficiency.
[0041] The product of the above embodiment needs to be fine-machined after casting.
Claims
1. A bimetallic brake drum with a pre-embedded steel mesh, comprising a steel material portion and a cast iron friction portion, characterized in that: The steel material part includes an embedded steel mesh on the outside of the drum part, a steel flange part and a steel transition part, and the steel transition part is connected between the embedded steel mesh and the steel flange part; the cast iron friction part is cast combined with the drum part, and part of the cast iron material of the cast iron friction part is cast into the mesh of the embedded steel mesh on the outside of the drum part.
2. The bimetallic brake drum with embedded steel mesh according to claim 1, characterized in that: The steel flange part and the steel transition part are annular structures, which are made by integrally stamping steel plate materials. The pre-buried steel mesh on the outer side of the drum part is a cylindrical steel mesh, which is made by stamping steel plates or weaving steel wire materials.
3. The bimetallic brake drum with embedded steel mesh according to claim 2, characterized in that: The connection structure between the embedded steel mesh on the outer side of the brake drum tube and the steel transition portion is a welding connection structure or an integral stamping structure.
4. The bimetallic brake drum with embedded steel mesh according to claim 3 is characterized in that: The pre-buried steel mesh on the outer side of the drum portion is annularly welded to the steel transition portion, and the casting area of the cast iron friction portion covers the welded connection ring between the pre-buried steel mesh and the transition portion.
5. The bimetallic brake drum with embedded steel mesh according to any one of claims 1 to 4, characterized in that: The mesh holes of the embedded steel mesh outside the drum part are square or diamond-shaped, and the mesh size is between 10*10 mm and 30*30 mm. The cross-section of the steel mesh wire is square, and the size is not less than 5*5 mm.
6. The bimetallic brake drum with embedded steel mesh according to claim 5, characterized in that: The mesh size of the pre-buried steel mesh on the outer side of the drum portion gradually decreases from the proximal end of the flange to the distal end of the flange.
7. The bimetallic brake drum with embedded steel mesh according to claim 5, characterized in that: The wire size of the steel mesh pre-buried on the outer side of the drum portion gradually increases from the proximal end of the flange to the distal end of the flange.
8. The bimetallic brake drum with embedded steel mesh according to any one of claims 1 to 4, characterized in that: The mesh holes of the embedded steel mesh outside the drum part are square or diamond-shaped, the mesh hole size is between 10*10 mm and 30*30 mm, the cross-section of the steel mesh wire is circular, and the diameter of the wire size is not less than 5 mm.
9. The bimetallic brake drum with embedded steel mesh according to claim 8, characterized in that: The mesh size of the pre-buried steel mesh on the outer side of the drum portion gradually decreases from the proximal end of the flange to the distal end of the flange.
10. The bimetallic brake drum with embedded steel mesh according to claim 8, characterized in that: The wire size of the steel mesh pre-buried on the outer side of the drum portion gradually increases from the proximal end of the flange to the distal end of the flange.