Brake hub with three metal structures and manufacturing method thereof

Abstract

The present invention belongs to the technical field of automobile brakes, and specifically, relates to a brake hub with a three-metal structure and a manufacturing process thereof, wherein the brake hub comprises a three-layer structure of an inner layer, a middle layer and an outer layer, wherein the inner layer is a wear-resistant alloy cast iron layer, the middle layer is a spun forged steel layer, and the outer layer is an aluminum alloy heat dissipation layer. The wheel hub end face of the brake hub is provided with heat dissipation holes along the circumferential direction, and the inner ring of the spun forged steel layer is processed with a thread groove for increasing the bonding force between the spun forged steel layer and the wear-resistant alloy cast iron layer. The manufacturing process of the brake hub comprises the following steps: 1) utilizing a spun forged steel layer to manufacture a spun forged steel layer, 2) utilizing a centrifugal casting process to cast a wear-resistant alloy cast iron layer on the inner side of the spun forged steel layer, and 3) utilizing a plasma spraying process to spray an aluminum alloy heat dissipation layer on the outer side of the spun forged steel layer. The process of the present invention is simple and has high reliability. The prepared brake hub with a three-metal structure not only retains the advantages of a bimetallic brake hub, but also solves the problems of cracking and high-temperature failure of the bimetallic brake hub.

Description

Technical Field

[0001] The invention belongs to the technical field of automobile brakes, and in particular relates to a brake hub with a three-metal structure and a manufacturing method thereof. Background Art

[0002] Automobile brakes are mainly divided into two categories. One is disc brake, the core component of which is the brake disc. It is characterized by fast response and is mainly used in high-speed passenger cars (sedans). The other is hub brake, the core component of which is the brake hub. It is characterized by large braking force and is mainly used in trucks or buses. The brake hub is an important safety part of large trucks, and whether it can brake quickly and effectively is crucial to the safety of the truck.

[0003] Existing brake hubs are mostly cast iron parts. Cast iron parts have a large friction coefficient and wear resistance, but low tensile strength, high brittleness, and a risk of cracking during use. In recent years, bimetallic composite brake hubs have appeared. The outer wall steel shell is made of forged steel material by spinning, while the inner annular friction surface is directly cast with cast iron material with good friction performance to form a whole. The friction and strength functions of the brake hub are separated and performed by two different metal materials respectively. The design is more flexible and can better play the advantages of different materials. The braking force is stronger, the service life is longer, and the weight or inertia is smaller. However, these bimetallic brake hubs have cracking caused by inconsistent thermal expansion coefficients of the bimetals and high-temperature failure caused by long-distance braking. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a brake hub with a three-metal structure, which includes an inner layer, a middle layer and an outer layer. The inner layer is a wear-resistant alloy cast iron layer, the middle layer is a spun forged steel layer, and the outer layer is an aluminum alloy heat dissipation layer. The hub end face of the brake hub is provided with heat dissipation holes along the circumferential direction, and the inner ring of the spun forged steel layer is processed with a threaded groove for increasing the bonding force between the spun forged steel layer and the wear-resistant alloy cast iron layer.

[0005] Preferably, the wear-resistant alloy cast iron layer is centrifugally cast on the inner side of the spinning forged steel layer, which has strong bonding force and is beneficial to improving the strength of the device; the aluminum alloy heat dissipation layer is sprayed on the outer side of the spinning forged steel layer, which is convenient for construction and has good heat dissipation.

[0006] As another aspect of the present invention, the present invention provides a method for manufacturing a brake hub with a tri-metal structure, characterized in that it comprises the following steps:

[0007] 1) Manufacturing the spun forged steel layer: using the spinning process to spin-form the forged steel thin-walled plate into a spun forged steel layer blank, using a lathe to process the end face and inner hole of the spun forged steel layer blank, and processing the thread groove on the inner side of the spun forged steel layer blank, and using a drilling machine to process the heat dissipation holes and threaded holes on the end face of the spun forged steel layer blank to obtain the spun forged steel layer.

[0008] 2) Casting a wear-resistant alloy cast iron layer: A centrifugal casting process is used to cast a wear-resistant alloy cast iron layer on the inner side of the spinning forged steel layer. The alloy composition of the wear-resistant alloy cast iron layer is: C: 3.0-3.55wt%, Si: 1.80-3.10wt%, Mn: 0.40-1.10wt%, P: 0.30-0.80wt%, S: <0.12wt%, Cu: <1.50wt%, Cr: 0.31-0.65wt%, and the rest is Fe.

[0009] 3) Spraying aluminum alloy heat dissipation layer: Aluminum alloy powder with a particle size of 140-270 mesh is sprayed on the outer side of the spin-forged steel layer by a plasma spraying process to obtain an aluminum alloy heat dissipation layer.

[0010] Preferably, in the centrifugal casting process, the various alloy components of the wear-resistant alloy cast iron layer are added to the smelting furnace in proportion, and the alloy solution is obtained after the smelting temperature and chemical composition are qualified. The processed spun forged steel layer is placed in the centrifugal casting outer mold, and the inner hole of the spun forged steel layer is heated by natural gas, and the temperature is controlled to 450-650°C. After adding 0.15-0.5wt% of silicon calcium barium inoculant to the alloy solution, centrifugal casting is carried out. When the temperature of the alloy solution drops below the eutectic temperature, mist water is sprayed into the inner hole to cool it down, so as to first reduce the temperature of the wear-resistant alloy cast iron layer in the inner hole. When the temperature reaches 600-800°C, the centrifugal casting outer mold is sprayed with water for cooling. When the temperature of the workpiece is lower than 600°C, it is removed from the mold for natural cooling.

[0011] Preferably, in the plasma spraying process, the outer circle of the spinning forged steel layer is firstly subjected to shot peening, the particle size of the brown corundum sand used for shot peening is 16-24 mesh, and the pressure of the compressed air is 4kg / cm 2 , the sand blasting angle is 50-90°, the sand blasting distance is 60-130mm, and the outer circle of the spinning forged steel layer is preheated after shot peening at a temperature of 60-100°C, and then plasma spraying is performed. The spraying current is 500-520A, the voltage is 70-72V, the spray distance is 100-120mm, and the argon flow rate is 37-38L / min.

[0012] The present invention also includes other devices, components and manufacturing steps that can enable the normal use of the three-metal structure brake hub and its manufacturing method, all of which are conventional technical means in the field; in addition, the devices, components and manufacturing steps not limited in the present invention all adopt conventional technical means in the field.

[0013] The working principle of the present invention is that the inner wear-resistant alloy cast iron layer mainly provides the friction coefficient and improves the wear resistance, the middle layer of the spinning forged steel layer plays the role of improving the overall strength of the brake hub, and the outer aluminum alloy heat dissipation layer mainly plays the role of reducing the temperature of the brake hub. The heat dissipation holes can enhance the heat dissipation effect of the brake hub, and the thread grooves can increase the bonding force between the spinning forged steel layer and the wear-resistant alloy cast iron layer, thereby improving the strength of the device and preventing cracking. In the manufacturing process of the device, centrifugal casting is the core process, and the Cr in the wear-resistant alloy cast iron layer is controlled at 0.31-0.65wt%, which is used to increase the supercooling degree of the material, refine the grains, and improve the wear resistance. The inner hole of the spinning forged steel layer is heated by natural gas, and the temperature is controlled to 450-650℃, which is mainly to ensure that the spinning forged steel layer shrinks simultaneously when the subsequent wear-resistant alloy cast iron layer cools and shrinks, so that the steel shell and the centrifugal casting layer are tightly combined. 0.15-0.5wt% of silicon calcium barium inoculant is added to the alloy solution, mainly to control the organization of the centrifugal casting layer and take into account the tensile strength of the product.

[0014] The beneficial effects of the present invention are that the process is simple and the reliability is high. The prepared brake hub with a tri-metal structure retains the advantages of a bimetallic brake hub and solves the problems of cracking and high-temperature failure of the bimetallic brake hub. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0016] Figure 1 Schematic diagram of the three-dimensional structure of the present invention in the embodiment.

[0017] Figure 2 yes Figure 1 Schematic diagram of the back structure.

[0018] Figure 3 yes Figure 2 AA section structure schematic diagram.

[0019] Figure 4 yes Figure 3 A partial enlarged schematic diagram of the G-section structure. DETAILED DESCRIPTION

[0020] The present invention is described clearly below in conjunction with the drawings and specific embodiments in the embodiments of the present invention. The description herein is only used to explain the present invention, but is not intended to limit the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work, any modifications, equivalent substitutions, improvements, etc., should be included in the protection scope of the present invention.

[0021] Example 1

[0022] like Figures 1 to 4As shown, the present invention provides a brake hub with a three-metal structure, the brake hub includes a three-layer structure of an inner layer, an intermediate layer and an outer layer, wherein the inner layer is a wear-resistant alloy cast iron layer 1, the intermediate layer is a spun forged steel layer 2, and the outer layer is an aluminum alloy heat dissipation layer 3. The hub end face of the brake hub is provided with heat dissipation holes 4 along the circumferential direction, and the inner ring of the spun forged steel layer 2 is processed with a thread groove 5 for increasing the bonding force between the spun forged steel layer 2 and the wear-resistant alloy cast iron layer 1. The wear-resistant alloy cast iron layer 1 is centrifugally cast on the inner side of the spun forged steel layer 2, and has a strong bonding force, which is beneficial to improving the strength of the device; the aluminum alloy heat dissipation layer 3 is sprayed on the outer side of the spun forged steel layer 2, which is convenient for construction and has good heat dissipation.

[0023] The working principle of the present invention is that the inner wear-resistant alloy cast iron layer 1 mainly provides the friction coefficient and improves the wear resistance, the middle layer of the spun forged steel layer 2 improves the overall strength of the brake hub, and the outer aluminum alloy heat dissipation layer 3 mainly reduces the temperature of the brake hub.

[0024] Example 2

[0025] like Figures 1 to 4 As shown, the present invention provides a method for manufacturing a brake hub with a three-metal structure based on Example 1, comprising the following steps:

[0026] 1) Manufacturing the spun forged steel layer 2: using a spinning process to spin-form a forged steel thin-walled plate into a spun forged steel layer blank, using a lathe to process the end face and inner hole of the spun forged steel layer blank, and processing a thread groove 5 on the inner side of the spun forged steel layer blank, and using a drilling machine to process heat dissipation holes 4 and threaded holes on the end face of the spun forged steel layer blank to obtain the spun forged steel layer 2.

[0027] 2) Casting the wear-resistant alloy cast iron layer 1: The wear-resistant alloy cast iron layer 1 is cast on the inner side of the spinning forged steel layer 2 by a centrifugal casting process, and the alloy composition of the wear-resistant alloy cast iron layer 1 is: C: 3.0wt%, Si: 1.80wt%, Mn: 0.40wt%, P: 0.30wt%, S: 0.10wt%, Cu: 1.10wt%, Cr: 0.31wt%, and the rest is Fe.

[0028] 3) Spraying the aluminum alloy heat dissipation layer 3: Aluminum alloy powder with a particle size of 140 mesh is sprayed on the outer side of the spin-forged steel layer 2 by a plasma spraying process to obtain the aluminum alloy heat dissipation layer 3.

[0029] In the centrifugal casting process, the various alloy components of the wear-resistant alloy cast iron layer 1 are added to the smelting furnace in proportion, and the alloy solution is obtained after the smelting temperature and chemical composition are qualified. The processed spinning forged steel layer 2 is placed in the centrifugal casting outer mold, and the inner hole of the spinning forged steel layer 2 is heated with natural gas, and the temperature is controlled to 450°C. After adding 0.5wt% of silicon calcium barium inoculant to the alloy solution, centrifugal casting is carried out. When the temperature of the alloy solution drops below the eutectic temperature, mist water is sprayed into the inner hole to cool it down, so as to first reduce the temperature of the wear-resistant alloy cast iron layer 1 in the inner hole. When the temperature reaches 600°C, the centrifugal casting outer mold is sprayed with water for cooling. When the temperature of the workpiece is lower than 600°C, it is removed from the mold for natural cooling. In the plasma spraying process, the outer circle of the spinning forged steel layer 2 is first shot peened. The particle size of the brown corundum sand used for shot peening is 16 mesh, and the pressure of the compressed air is 4kg / cm 2 , the sand blasting angle is 50°, the sand blasting distance is 60mm, and the outer circle of the spinning forged steel layer 2 is preheated to 60°C after shot peening, and then plasma spraying is carried out, the spraying current is 500A, the voltage is 70V, the spray distance is 100mm, and the argon gas flow rate is 37L / min.

[0030] Example 3

[0031] like Figures 1 to 4 As shown, the present invention provides a method for manufacturing a brake hub with a three-metal structure based on Example 1, comprising the following steps:

[0032] 1) Manufacturing the spun forged steel layer 2: using a spinning process to spin-form a forged steel thin-walled plate into a spun forged steel layer blank, using a lathe to process the end face and inner hole of the spun forged steel layer blank, and processing a thread groove 5 on the inner side of the spun forged steel layer blank, and using a drilling machine to process heat dissipation holes 4 and threaded holes on the end face of the spun forged steel layer blank to obtain the spun forged steel layer 2.

[0033] 2) Casting the wear-resistant alloy cast iron layer 1: The wear-resistant alloy cast iron layer 1 is cast on the inner side of the spinning forged steel layer 2 by a centrifugal casting process, and the alloy composition of the wear-resistant alloy cast iron layer 1 is: C: 3.30wt%, Si: 2.20wt%, Mn: 0.80wt%, P: 0.50wt%, S: 0.11wt%, Cu: 1.25wt%, Cr: 0.50wt%, and the rest is Fe.

[0034] 3) Spraying the aluminum alloy heat dissipation layer 3: Aluminum alloy powder with a particle size of 190 mesh is sprayed on the outer side of the spin-forged steel layer 2 by a plasma spraying process to obtain the aluminum alloy heat dissipation layer 3.

[0035] In the centrifugal casting process, the various alloy components of the wear-resistant alloy cast iron layer 1 are added to the smelting furnace in proportion, and the alloy solution is obtained after the smelting temperature and chemical composition are qualified. The processed spinning forged steel layer 2 is placed in the centrifugal casting outer mold, and the inner hole of the spinning forged steel layer 2 is heated with natural gas, and the temperature is controlled to 550°C. After adding 0.35wt% of silicon calcium barium inoculant to the alloy solution, centrifugal casting is carried out. When the temperature of the alloy solution drops below the eutectic temperature, mist water is sprayed into the inner hole to cool it down, so as to first reduce the temperature of the wear-resistant alloy cast iron layer 1 in the inner hole. When the temperature reaches 700°C, the centrifugal casting outer mold is sprayed with water for cooling. When the temperature of the workpiece is lower than 600°C, it is removed from the mold for natural cooling. In the plasma spraying process, the outer circle of the spinning forged steel layer 2 is first shot peened. The particle size of the brown corundum sand used for shot peening is 20 mesh, and the pressure of the compressed air is 4kg / cm 2 , the sand blasting angle is 70°, the sand blasting distance is 90mm, and the outer circle of the spinning forged steel layer 2 is preheated to 80°C after shot peening, and then plasma spraying is carried out, the spraying current is 510A, the voltage is 71V, the spray distance is 110mm, and the argon gas flow rate is 37.5L / min.

[0036] Example 4

[0037] like Figures 1 to 4 As shown, the present invention provides a method for manufacturing a brake hub with a three-metal structure based on Example 1, comprising the following steps:

[0038] 1) Manufacturing the spun forged steel layer 2: using a spinning process to spin-form a forged steel thin-walled plate into a spun forged steel layer blank, using a lathe to process the end face and inner hole of the spun forged steel layer blank, and processing a thread groove 5 on the inner side of the spun forged steel layer blank, and using a drilling machine to process heat dissipation holes 4 and threaded holes on the end face of the spun forged steel layer blank to obtain the spun forged steel layer 2.

[0039] 2) Casting the wear-resistant alloy cast iron layer 1: The wear-resistant alloy cast iron layer 1 is cast on the inner side of the spinning forged steel layer 2 by a centrifugal casting process, and the alloy composition of the wear-resistant alloy cast iron layer 1 is: C: 3.55wt%, Si: 3.10wt%, Mn: 1.10wt%, P: 0.80wt%, S: 0.11wt%, Cu: 1.40wt%, Cr: 0.65wt%, and the rest is Fe.

[0040] 3) Spraying the aluminum alloy heat dissipation layer 3: Aluminum alloy powder with a particle size of 270 mesh is sprayed on the outer side of the spin-forged steel layer 2 by a plasma spraying process to obtain the aluminum alloy heat dissipation layer 3.

[0041] In the centrifugal casting process, the various alloy components of the wear-resistant alloy cast iron layer 1 are added to the smelting furnace in proportion, and the alloy solution is obtained after the smelting temperature and chemical composition are qualified. The processed spinning forged steel layer 2 is placed in the centrifugal casting outer mold, and the inner hole of the spinning forged steel layer 2 is heated with natural gas, and the temperature is controlled to 650°C. After adding 0.5wt% of silicon calcium barium inoculant to the alloy solution, centrifugal casting is carried out. When the temperature of the alloy solution drops below the eutectic temperature, mist water is sprayed into the inner hole to cool it down, so as to first reduce the temperature of the wear-resistant alloy cast iron layer 1 in the inner hole. When the temperature reaches 800°C, the centrifugal casting outer mold is sprayed with water for cooling. When the temperature of the workpiece is lower than 600°C, it is removed from the mold for natural cooling. In the plasma spraying process, the outer circle of the spinning forged steel layer 2 is first shot peened. The particle size of the brown corundum sand used for shot peening is 24 mesh, and the pressure of the compressed air is 4kg / cm 2 , the sand blasting angle is 90°, the sand blasting distance is 130mm, and the outer circle of the spinning forged steel layer 2 is preheated to 100°C after shot peening, and then plasma spraying is carried out. The spraying current is 520A, the voltage is 72V, the spray distance is 120mm, and the argon flow rate is 38L / min.

[0042] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A method for manufacturing a brake hub with a tri-metal structure, characterized in that: The brake hub comprises a three-layer structure of an inner layer, an intermediate layer and an outer layer, wherein the inner layer is a wear-resistant alloy cast iron layer, the intermediate layer is a spun forged steel layer, and the outer layer is an aluminum alloy heat dissipation layer. The hub end face of the brake hub is provided with heat dissipation holes along the circumferential direction. The inner ring of the spun forged steel layer is processed with a thread groove for increasing the bonding force between the spun forged steel layer and the wear-resistant alloy cast iron layer. The wear-resistant alloy cast iron layer is centrifugally cast on the inner side of the spun forged steel layer. The alloy composition of the wear-resistant alloy cast iron layer is: C: 3.0-3.55wt%, Si: 1.80-3.10wt%, Mn: 0.40-1.10wt%, P: 0.30-0.80wt%, S: <0.12wt%, Cu: <1.50wt%, Cr: 0.31-0.65wt%, and the rest is Fe; the aluminum alloy heat dissipation layer is sprayed on the outer side of the spun forged steel layer; and the manufacturing method comprises the following steps: 1) Manufacturing the spinning forged steel layer: using the spinning process to spin-form the forged steel thin-walled plate into a spinning forged steel layer blank, using a lathe to process the end face and inner hole of the spinning forged steel layer blank, and processing the thread groove on the inner side of the spinning forged steel layer blank, and using a drilling machine to process the heat dissipation holes and threaded holes on the end face of the spinning forged steel layer blank to obtain the spinning forged steel layer; 2) Casting the wear-resistant alloy cast iron layer: using a centrifugal casting process to cast the wear-resistant alloy cast iron layer on the inner side of the spinning forged steel layer; in the centrifugal casting process, the various alloy components of the wear-resistant alloy cast iron layer are added to the smelting furnace in proportion, and the alloy solution is obtained after the smelting temperature and chemical composition are qualified, and the processed spinning forged steel layer is placed in the centrifugal casting outer mold, and the inner hole of the spinning forged steel layer is heated by natural gas, and the temperature is controlled to 450-650°C, and 0.15-0.5wt% of silicon calcium barium inoculant is added to the alloy solution and then centrifugal casting is performed. When the temperature of the alloy solution drops below the eutectic temperature, mist water is sprayed into the inner hole to cool it down, so as to first reduce the temperature of the wear-resistant alloy cast iron layer in the inner hole, and when the temperature reaches 600-800°C, the centrifugal casting outer mold is sprayed with water for cooling, and when the temperature of the workpiece is lower than 600°C, it is removed from the mold for natural cooling; 3) Spraying aluminum alloy heat dissipation layer: Aluminum alloy powder with a particle size of 140-270 mesh is sprayed on the outer side of the spin-forged steel layer by a plasma spraying process to obtain an aluminum alloy heat dissipation layer.

2. The method for manufacturing a brake hub with a tri-metal structure according to claim 1, characterized in that: In the plasma spraying process, the outer circle of the spinning forged steel layer is firstly shot peened. The particle size of the brown corundum sand used for shot peening is 16-24 mesh, and the pressure of the compressed air is 4kg / cm 2 , the sand blasting angle is 50-90°, the sand blasting distance is 60-130mm, and the outer circle of the spinning forged steel layer is preheated after shot peening at a temperature of 60-100°C, and then plasma spraying is performed. The spraying current is 500-520A, the voltage is 70-72V, the spray distance is 100-120mm, and the argon flow rate is 37-38L / min.

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