Insulating bearing inner ring machining method in field of new energy automobiles

Abstract

The invention discloses a machining method for an insulating bearing inner ring in the field of new energy automobiles. The machining method comprises the following steps that S1, a steel raw material is subjected to spheroidizing annealing heat treatment, turning treatment and martensite quenching and tempering treatment, and a to-be-machined inner ring is obtained; s2, a stamping die is prepared; s3, the aluminum alloy plate is subjected to stamping machining through a stamping die to obtain a circular ring piece, and the circular ring piece is subjected to stamping machining through the stamping die to obtain a neck bush; s4, sleeving the neck bush and the inner ring to be processed to obtain an inner ring to be insulated; s5, the inner ring to be insulated is subjected to anodic oxidation treatment, and an inner ring to be ground is obtained; s6, grinding the inner ring to be ground to obtain a finished inner ring; and S7, carrying out breakdown voltage test on the inner ring of the finished product. The problem that in the prior art, an insulation bearing inner ring machining method which can produce insulation bearing inner rings meeting the insulation requirement that the direct-current breakdown voltage is larger than 800 V and is high in production efficiency and low in production cost is lacked is solved.

Description

Technical Field

[0001] This invention relates to the field of bearing component manufacturing technology, specifically a method for machining the inner ring of an insulated bearing in the field of new energy vehicles. Background Technology

[0002] With the rapid development of the global new energy vehicle industry, the performance requirements of drive motors, as the core power components of new energy vehicles, are continuously increasing, especially in terms of voltage levels. To meet the demands for higher range and power output, drive motor voltages have been gradually upgraded from the traditional 400V system to the 800V high-voltage system. However, the increase in voltage level directly leads to severe electro-corrosion problems for motor bearings: the shaft voltage generated during motor operation will form current through the bearings, causing damage such as electro-erosion pits and peeling on the bearing raceways and rolling element surfaces, significantly shortening the bearing's service life, and even causing motor failure, seriously affecting the operational safety and reliability of new energy vehicles. Therefore, effective insulation treatment of motor bearings has become a key technical requirement for the research and development and mass production of 800V high-voltage drive motors.

[0003] Currently, the industry's solutions for bearing insulation mainly fall into three categories: First, using ceramic balls to replace traditional steel rolling elements, utilizing the insulating properties of ceramic materials to achieve overall bearing insulation. However, ceramic balls are expensive and require stringent processing precision, which significantly increases the manufacturing cost of bearings. They also suffer from poor compatibility with steel bearing rings and insufficient impact resistance, making it difficult to meet the low-cost, high-reliability mass production requirements of new energy vehicles. Secondly, preparing an alumina insulating coating on the bearing ring surface to block the shaft current path requires complex processes such as high-temperature sintering and plasma spraying, resulting in long production cycles, low efficiency, and the coating being prone to cracking and peeling, leading to unstable insulation performance and difficulty in ensuring consistent insulation effects during mass production. Furthermore, the equipment investment and process control costs during coating preparation are also high. Thirdly, while coating the bearing surface with an insulating plastic layer using a plastic coating process is relatively low-cost, the plastic layer has poor temperature resistance and wear resistance, making it prone to aging and damage under the high temperature and vibration conditions of motor operation, resulting in a short insulation life. Moreover, it is difficult to ensure a tight fit between the plastic layer and the bearing ring surface during the plastic coating process, easily forming bubbles or gaps, which cannot meet the insulation strength requirements (especially DC breakdown voltage) under an 800V high-voltage system. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a method for machining the inner ring of an insulated bearing in the field of new energy vehicles. This method aims to solve the problem of the lack of an insulated bearing inner ring that can produce insulated bearing inner rings with high production efficiency and low production cost, while meeting the insulation requirements of DC breakdown voltage greater than 800V.

[0005] To achieve the above objectives, this invention provides a method for machining the inner ring of an insulated bearing in the field of new energy vehicles, comprising the following steps: S1. The steel raw material is subjected to spheroidizing annealing heat treatment, machining treatment and martensitic quenching and tempering treatment to obtain the inner ring to be machined; S2. Prepare the first stamping die, the second stamping die, and the third stamping die; S3. The aluminum alloy sheet is stamped through the first stamping die to obtain a ring piece, the ring piece is stamped through the second stamping die to obtain the inner bushing to be processed, and the inner bushing to be processed is stamped through the third stamping die to obtain the inner bushing with a flange. S4. Combine the inner bushing from step S2 with the inner ring to be processed to form the inner ring to be insulated, and then perform stamping processing through the third stamping die. S5. The inner ring to be insulated, which has been stamped, is masked with masking glue on the raceway and the flange, and then anodized to obtain the inner ring to be ground. S6. Grind the raceway, inner diameter and end face of the inner ring to be ground after anodizing to obtain the finished inner ring. S7. Perform DC breakdown voltage test and AC breakdown voltage test on the inner ring of the finished product.

[0006] The present invention further includes: steps S2 and S3, which further include an upper stamping plate and a lower bearing plate for linkage with external stamping equipment. The first stamping die includes a first upper die and a first lower die. The first upper die includes an annular outer protruding ring and an annular inner protruding ring. Both the outer and inner protruding rings are disposed on the upper stamping plate. The outer protruding ring is located outside the inner protruding ring and is coaxially arranged with the inner protruding ring. The inner peripheral wall of the outer protruding ring and the outer peripheral wall of the inner protruding ring are clearance-fitted and form a first stamping groove. The first lower die includes an outer concave annular groove and an inner concave annular groove circumferentially opened on the lower bearing plate. The outer protruding ring and the outer concave annular groove are correspondingly arranged, and the inner protruding ring and the inner concave annular groove are correspondingly arranged. The annular piece is manufactured by stamping process through the cooperation of the outer protruding ring and the outer concave annular groove and the inner protruding ring and the inner concave annular groove.

[0007] The present invention further comprises: the second stamping die in steps S2 and S3 includes an outwardly protruding truncated cone and an outwardly protruding circular edge circumferentially disposed at the bottom of the outer peripheral wall of the outwardly protruding truncated cone. The outwardly protruding truncated cone is disposed on the upper stamping plate, and a first concave circular hole is formed on the lower bearing plate. A first concave annular groove is circumferentially formed on the inner peripheral wall of the opening of the first concave annular hole. A first stepped surface is formed by combining the inner peripheral wall of the first concave annular groove and the inner peripheral wall of the first concave circular hole. The first stepped surface is correspondingly disposed to the outwardly protruding ring, and the first concave circular hole is correspondingly disposed to the outwardly protruding truncated cone. The inner bushing to be processed is manufactured by a pre-stamping process through the cooperation of the first stepped surface and the outwardly protruding circular edge and the cooperation of the first concave circular hole and the outwardly protruding truncated cone.

[0008] The present invention further comprises: the second stamping die in steps S2 and S3 includes an outwardly protruding cylinder and an outwardly protruding ring edge circumferentially disposed at the bottom of the outer peripheral wall of the outwardly protruding cylinder; the outwardly protruding cylinder has a machining hole axially passing through it; the outwardly protruding cylinder is disposed on the upper stamping plate; the lower bearing plate has a second concave circular hole; a second concave annular groove is circumferentially formed on the inner peripheral wall of the opening of the second concave circular hole; a second stepped surface is formed by combining the inner peripheral wall of the second concave annular groove and the inner peripheral wall of the second concave circular hole; the inner bushing with the retaining edge is manufactured by the final stamping process through the cooperation of the first stepped surface and the outwardly protruding ring edge and the cooperation of the first concave circular hole and the outwardly protruding cylinder.

[0009] The present invention further includes the following step: In step S4, the inner ring to be insulated is processed by stamping through the cooperation of the second stepped surface and the outer protruding round edge, and the cooperation of the second concave round hole and the outer protruding conical truncated cone.

[0010] The present invention further includes the following steps in the anodizing process of step S5: S5.1. Immerse the inner ring to be insulated in a brightening cleaning agent at room temperature for 4 minutes, and then wash it with water. S5.2. Based on step S5.1, immerse the inner ring to be insulated in an alkaline etchant at 50 degrees Celsius for 5 minutes and then wash it with water. S5.3. Based on step S5.2, immerse the inner ring to be insulated at room temperature until it reaches 30%. After 3 minutes, rinse with water. S5.4. Based on step S5.3, heat the inner ring to be insulated at 20 degrees Celsius. and The mixed solution was subjected to oxidation treatment for 40 minutes at a current density of [missing value]. Then, it undergoes a water washing process; S5.5 Based on step S5.4, the inner ring to be insulated is sealed in a sealant at 28 degrees Celsius, and then washed with water. S5.6. Based on step S5.4, the inner ring after sealing is dried.

[0011] The advantages of adopting the above technical solution are as follows: This invention lays the foundation for the performance of the inner ring by sequentially subjecting the steel raw material to spheroidizing annealing heat treatment, machining, and martensitic quenching and tempering; using multiple sets of structurally compatible stamping dies, aluminum alloy plates are precisely stamped to efficiently prepare inner bushings with different structures, ensuring the forming accuracy and processing efficiency of the inner bushings; and the inner bushings are stamped after being fitted with the inner ring to be processed, enhancing the tightness of their fit; during the anodizing process, multiple steps of cleaning, oxidation, and sealing processes improve the uniformity and density of the insulation layer on the surface of the inner ring, effectively enhancing the insulation performance; subsequent grinding and breakdown voltage testing further ensure the dimensional accuracy and insulation reliability of the finished inner ring. The overall process balances production efficiency and processing quality, and can stably produce insulated bearing inner rings that meet the requirements of high-voltage drive motors for new energy vehicles. Through the above processing method, while meeting the insulation performance requirements, the production process is reduced, production efficiency is improved, and the problem of balancing insulation performance, production efficiency, and cost in existing technologies is solved. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the processing of the insulating inner ring in this invention; Figure 2 This is a three-dimensional view of the upper stamping plate in this invention; Figure 3 This is a three-dimensional view of the lower bearing plate in this invention; Figure 4 This is a line graph showing the DC breakdown voltage test results in this invention; Figure 5 This is a line graph showing the AC breakdown voltage test results in this invention. Detailed Implementation Specific Implementation Example 1: This invention provides a method for machining the inner ring of an insulated bearing in the field of new energy vehicles, comprising the following steps: S1. The material selected is high-quality steel GCr15 material according to GB / T 18254 standard. The steel raw material is subjected to spheroidizing annealing heat treatment, turning treatment and martensitic quenching and tempering treatment to obtain the inner ring to be processed. The inner diameter of the inner ring to be processed is 25mm and the effective wall thickness is 10mm. S2. Prepare the first stamping die, the second stamping die, and the third stamping die; S3. Select aluminum alloy conforming to GB / T 3190 standard, with a plate thickness of 0.5mm. The aluminum alloy plate is stamped through the first stamping die to obtain a ring piece. The ring piece is stamped through the second stamping die to obtain the inner bushing to be processed. The inner bushing to be processed is stamped through the third stamping die to obtain the inner bushing with a flange. S4. Combine the inner bushing from step S2 with the inner ring to be processed to form the inner ring to be insulated, and then perform stamping processing through the third stamping die. S5. The inner ring to be insulated, which has been stamped, is masked with masking glue on the raceway and the flange, and then anodized to obtain the inner ring to be ground. S6. Grind the raceway, inner diameter and end face of the inner ring to be ground after anodizing to obtain the finished inner ring. S7. Perform DC breakdown voltage test and AC breakdown voltage test on the inner ring of the finished product.

[0014] The present invention further includes, in steps S2 and S3, an upper stamping plate and a lower bearing plate for linkage with external stamping equipment. The first stamping die includes a first upper die and a first lower die. The first upper die includes an annular outer protruding ring and an annular inner protruding ring. Both the outer and inner protruding rings are disposed on the upper stamping plate. The outer protruding ring is located outside the inner protruding ring and is coaxially arranged with the inner protruding ring. The inner peripheral wall of the outer protruding ring and the outer peripheral wall of the inner protruding ring are clearance-fitted and form a first stamping groove. The first lower die includes an outer concave annular groove and an inner concave annular groove circumferentially opened on the lower bearing plate. The outer protruding ring and the outer concave annular groove are correspondingly arranged, and the inner protruding ring and the inner concave annular groove are correspondingly arranged. The annular piece is manufactured by stamping and cutting process through the cooperation of the outer protruding ring and the outer concave annular groove and the inner protruding ring and the inner concave annular groove.

[0015] Further, in the present invention: the second stamping die in steps S2 and S3 includes an outwardly protruding truncated cone and an outwardly protruding circular edge circumferentially disposed at the bottom of the outer peripheral wall of the outwardly protruding truncated cone. The outwardly protruding truncated cone is disposed on the upper stamping plate, and a first concave circular hole is formed on the lower bearing plate. A first concave annular groove is circumferentially formed on the inner peripheral wall of the opening of the first concave circular hole. A first stepped surface is formed by combining the inner peripheral wall of the first concave annular groove and the inner peripheral wall of the first concave circular hole. The first stepped surface is correspondingly disposed with the outwardly protruding ring, and the first concave circular hole is correspondingly disposed with the outwardly protruding truncated cone. The inner bushing to be processed is manufactured by a pre-stamping process through the cooperation of the first stepped surface and the outwardly protruding circular edge and the cooperation of the first concave circular hole and the outwardly protruding truncated cone.

[0016] Further, in the present invention: the second stamping die in steps S2 and S3 includes an outwardly protruding cylinder and an outwardly protruding ring edge circumferentially disposed at the bottom of the outer peripheral wall of the outwardly protruding cylinder. The outwardly protruding cylinder has a machining hole axially passing through it. The outwardly protruding cylinder is disposed on the upper stamping plate. The lower bearing plate has a second concave circular hole. A second concave annular groove is circumferentially formed on the inner peripheral wall of the opening of the second concave circular hole. A second stepped surface is formed by combining the inner peripheral wall of the second concave annular groove and the inner peripheral wall of the second concave circular hole. The second concave circular hole is correspondingly disposed with the outwardly protruding cylinder. The inner bushing with the retaining edge is manufactured by the final stamping process through the cooperation of the first stepped surface and the outwardly protruding ring edge and the cooperation of the first concave circular hole and the outwardly protruding cylinder.

[0017] Further, in step S4, the inner ring to be insulated is processed by a stamping process through the cooperation of the second stepped surface and the outer protruding round edge, and the cooperation of the second concave round hole and the outer protruding conical truncated cone.

[0018] The present invention further includes the following steps in the anodizing process of step S5: S5.1. Immerse the inner ring to be insulated in 50mL / L CLA-112 brightening cleaner at room temperature for 4 minutes, and then rinse with water. S5.2. Based on step S5.1, immerse the inner ring to be insulated in an alkaline etchant (50g / L NaOH, 20g / L CLA-201) at 50 degrees Celsius for 5 minutes, and then wash it with water. S5.3. Based on step S5.2, immerse the inner ring to be insulated at room temperature until it reaches 30%. After 3 minutes, rinse with water. S5.4. Based on step S5.3, heat the inner ring to be insulated at 20 degrees Celsius. (180g / L) and The oxidation process was carried out in a mixed solution of (3 g / L) for 40 min at a current density of [missing value]. Then, it undergoes a water washing process; S5.5 Based on step S5.4, the inner ring to be insulated is sealed at 28 degrees Celsius in 5 g / L CLA-701 sealant (pH value 6, rate 1.0 μm / min), and then washed with water. S5.6. Based on step S5.4, the inner ring after sealing is dried.

[0019] Final testing showed that, using the above processing methods, the DC breakdown voltage reached 1300V and the AC breakdown voltage reached 900V, meeting the requirements for use in new energy vehicles.

[0020] The markings in the attached drawings of the above instruction manual are as follows: upper stamping plate 1, outer protruding ring 11, inner protruding ring 111, outer protruding truncated cone 12, outer protruding circular edge 121, outer protruding cylinder 13, outer protruding ring edge 131, machining hole 132, lower bearing plate 2, outer concave ring groove 21, inner concave ring groove 211, first inner concave circular hole 22, first inner concave ring groove 221, first stepped surface 222, second inner concave circular hole 23, second inner concave ring groove 231, second stepped surface 232.

[0021] The foregoing has shown and described the basic principles and main features of the present invention, as well as its advantages. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the present invention. Various changes and modifications can be made to the present invention without departing from its spirit and scope. All such changes and modifications fall within the scope of the present invention as claimed, which is defined by the appended claims and their equivalents.

Claims

1. A method for machining the inner ring of an insulated bearing in the field of new energy vehicles, characterized in that: Includes the following steps: S1. The steel raw material is subjected to spheroidizing annealing heat treatment, machining treatment and martensitic quenching and tempering treatment to obtain the inner ring to be machined; S2. Prepare the first stamping die, the second stamping die, and the third stamping die; S3. The aluminum alloy sheet is stamped through the first stamping die to obtain a ring piece, the ring piece is stamped through the second stamping die to obtain the inner bushing to be processed, and the inner bushing to be processed is stamped through the third stamping die to obtain the inner bushing with a flange. S4. Combine the inner bushing from step S2 with the inner ring to be processed to form the inner ring to be insulated, and then perform stamping processing through the third stamping die. S5. The inner ring to be insulated, which has been stamped, is masked with masking glue on the raceway and the flange, and then anodized to obtain the inner ring to be ground. S6. Grind the raceway, inner diameter and end face of the inner ring to be ground after anodizing to obtain the finished inner ring. S7. Perform DC breakdown voltage test and AC breakdown voltage test on the inner ring of the finished product.

2. The method for machining the inner ring of an insulated bearing in the field of new energy vehicles according to claim 1, characterized in that: Steps S2 and S3 further include an upper stamping plate and a lower bearing plate for linkage with external stamping equipment. The first stamping die includes a first upper die and a first lower die. The first upper die includes an annular outer protruding ring and an annular inner protruding ring. Both the outer and inner protruding rings are disposed on the upper stamping plate. The outer protruding ring is located outside the inner protruding ring and is coaxially arranged with the inner protruding ring. The inner peripheral wall of the outer protruding ring and the outer peripheral wall of the inner protruding ring are clearance-fitted and form a first stamping groove. The first lower die includes an outer concave annular groove and an inner concave annular groove circumferentially opened on the lower bearing plate. The outer protruding ring and the outer concave annular groove are correspondingly arranged, and the inner protruding ring and the inner concave annular groove are correspondingly arranged. The annular piece is manufactured by stamping process through the cooperation of the outer protruding ring and the outer concave annular groove and the inner protruding ring and the inner concave annular groove.

3. The method for machining the inner ring of an insulated bearing in the field of new energy vehicles according to claim 2, characterized in that: The second stamping die in steps S2 and S3 includes an outwardly protruding truncated cone and an outwardly protruding circular edge circumferentially disposed at the bottom of the outer peripheral wall of the outwardly protruding truncated cone. The outwardly protruding truncated cone is disposed on the upper stamping plate, and a first concave circular hole is formed on the lower bearing plate. A first concave annular groove is circumferentially formed on the inner peripheral wall of the opening of the first concave annular hole. A first stepped surface is formed by combining the inner peripheral wall of the first concave annular groove and the inner peripheral wall of the first concave circular hole. The first stepped surface is correspondingly disposed to the outwardly protruding ring, and the first concave circular hole is correspondingly disposed to the outwardly protruding truncated cone. The inner bushing to be processed is manufactured by pre-stamping process through the cooperation of the first stepped surface and the outwardly protruding circular edge and the cooperation of the first concave circular hole and the outwardly protruding truncated cone.

4. The method for machining the inner ring of an insulated bearing in the field of new energy vehicles according to claim 3, characterized in that: The second stamping die in steps S2 and S3 includes an outwardly protruding cylinder and an outwardly protruding ring edge circumferentially disposed at the bottom of the outer peripheral wall of the outwardly protruding cylinder. The outwardly protruding cylinder has a machining hole axially through it. The outwardly protruding cylinder is disposed on the upper stamping plate. The lower bearing plate has a second concave circular hole. A second concave annular groove is circumferentially formed on the inner peripheral wall of the opening of the second concave circular hole. A second stepped surface is formed by combining the inner peripheral wall of the second concave annular groove and the inner peripheral wall of the second concave circular hole. The second concave circular hole is correspondingly disposed to the outwardly protruding cylinder. The inner bushing with the retaining edge is manufactured by the final stamping process through the cooperation of the first stepped surface and the outwardly protruding ring edge and the cooperation of the first concave circular hole and the outwardly protruding cylinder.

5. A method for machining the inner ring of an insulated bearing in the field of new energy vehicles according to claim 4, characterized in that: In step S4, the inner ring to be insulated is processed by stamping through the fit between the second stepped surface and the outer protruding round edge, and the fit between the second concave round hole and the outer protruding conical truncated cone.

6. A method for machining the inner ring of an insulated bearing in the field of new energy vehicles according to claim 1, characterized in that: The anodizing process in step S5 includes the following steps: S5.

1. Immerse the inner ring to be insulated in a brightening cleaning agent at room temperature for 4 minutes, and then wash it with water. S5.

2. Based on step S5.1, immerse the inner ring to be insulated in an alkaline etchant at 50 degrees Celsius for 5 minutes and then wash it with water. S5.

3. Based on step S5.2, immerse the inner ring to be insulated at room temperature until it reaches 30%. After 3 minutes, rinse with water. S5.

4. Based on step S5.3, heat the inner ring to be insulated at 20 degrees Celsius. and The mixed solution was subjected to oxidation treatment for 40 minutes at a current density of [missing value]. Then, it undergoes a water washing process; S5.5 Based on step S5.4, the inner ring to be insulated is sealed in a sealant at 28 degrees Celsius, and then washed with water. S5.

6. Based on step S5.4, the inner ring after sealing is dried.

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