A kind of automobile transmission shaft system fatigue resistance manufacturing method based on surface texture technology

Abstract

This invention discloses a fatigue-resistant manufacturing method for automotive driveshafts based on surface texture technology, belonging to the field of automotive parts manufacturing technology. First, the driveshaft workpiece, after machining and final heat treatment, undergoes surface cleaning and finishing to control the surface roughness Ra ≤ 0.8 μm. Combining finite element stress simulation and actual working condition load spectrum, high-fatigue target machining areas such as the shoulder transition fillet area and the spline tooth meshing area are identified and delineated. Pulsed lasers are used to process micro-textured units with adapted morphology and arrangement to the stress direction and failure mode of different areas. Then, abrasive flow polishing is used to passivate the textured edges, controlling the edge fillet radius ≥ 5 μm. An ultrasonic rolling pre-strengthening process can be added, and the final product is obtained after performance testing. This invention improves the fatigue life of the driveshaft system through zoned texture design, edge passivation treatment, and process synergy.

Description

Technical Field

[0001] This invention relates to the field of automotive parts manufacturing technology, and in particular to a fatigue-resistant manufacturing method for automotive drive shaft systems based on surface texture technology. Background Technology

[0002] The automotive driveshaft system is the core load-bearing component for power transmission in a vehicle. It is subjected to alternating torsion, bending, and contact loads over a long period of time. Fatigue fracture and pitting and spalling on the tooth surface are its main failure modes, which directly determine the driving safety and service life of the entire vehicle.

[0003] Surface texturing, as a novel surface modification technique, can actively control surface stress distribution and tribological properties by preparing regular morphologies at the micro- and nano-scale on the material surface, and has been applied in fields such as bearings and cutting tools. However, the engineering application of existing surface texturing schemes in automotive drive shaft systems still has significant drawbacks: First, most adopt texture designs with uniform parameters across the entire region, without considering the load characteristics and failure modes of different areas of the drive shaft system for zonal matching, resulting in limited performance improvement and potentially introducing stress concentration effects in some areas; Second, after laser texturing, molten burrs and microcracks are easily generated at the texture edges, which become new sources of fatigue initiation, negating the strengthening effect of the texturing itself; Third, existing schemes do not form a synergistic mechanism with traditional strengthening processes, making it difficult to fully leverage the strengthening advantages of multiple mechanisms superimposed. Summary of the Invention

[0004] The purpose of this invention is to provide a fatigue-resistant manufacturing method for automotive drive shaft systems based on surface texture technology. By using zoned texture design, edge passivation treatment, and process synergy, the fatigue life of the drive shaft system can be improved.

[0005] To achieve the above objectives, the present invention provides a fatigue-resistant manufacturing method for automotive drive shaft systems based on surface texture technology, comprising the following steps: S1. Workpiece pretreatment: The automotive transmission shaft workpiece that has undergone machining and final heat treatment is cleaned and finished to remove surface oil, oxide layer and machining burrs, and the surface roughness Ra of the workpiece is controlled to be ≤0.8μm. S2. High-risk area identification and delineation: By combining finite element stress simulation with the actual working condition load spectrum of the transmission shaft system, identify and delineate at least one target processing area on the workpiece surface that is prone to fatigue failure. S3, Zone-adaptive laser surface texture processing: Using pulsed laser processing equipment, micro-texture units with corresponding morphological parameters and arrangement are processed according to the stress direction and failure mode of different target processing areas. S4. Texture edge passivation treatment: The surface of the workpiece after texture processing is polished by abrasive flow polishing process to eliminate burrs and microcracks at the edges of microtexture units and control the radius of the texture edge rounded corners to be ≥5μm. S5. Performance Testing and Finished Product Output: Sampling tests are conducted on the surface morphology, residual stress, and fatigue life of the workpiece. After passing the tests, the fatigue-resistant transmission shaft system is obtained.

[0006] Preferably, in S1, the surface cleaning and finishing process sequentially employs alkaline solvent ultrasonic cleaning, deionized water rinsing, hot air drying, and ultra-fine abrasive belt polishing.

[0007] Preferably, the final heat treatment is carburizing and quenching, and the surface hardness of the workpiece after treatment is HRC≥58.

[0008] Preferably, in S2, the input conditions for finite element stress simulation include the rated torque, peak torque, speed fluctuation, and radial runout of the transmission shaft system.

[0009] Preferably, the target machining area includes any one or more combinations of the shoulder transition fillet area, spline tooth surface meshing area, and universal joint raceway contact area.

[0010] Preferably, in S3, the pulsed laser processing equipment uses a nanosecond pulsed fiber laser, and inert gas is used to purge and protect the processing area during the processing.

[0011] Preferably, the microtexture unit includes a microgroove texture arranged perpendicular to the principal stress direction in the region dominated by bending fatigue and a micro-dimple texture arranged in a lattice pattern in the region dominated by contact fatigue. The cross-section of the microgroove texture is arc-shaped, and the cross-section of the micro-dimple texture is hemispherical.

[0012] Preferably, in S4, the abrasive flow polishing uses silicon carbide abrasive particles.

[0013] Preferably, in S5, the surface residual stress is detected by X-ray diffraction, and the fatigue life is detected by torsional fatigue testing machine.

[0014] A fatigue-resistant manufacturing method for automotive drive shafts based on surface texture technology includes a surface pre-strengthening process between S2 and S3: ultrasonic rolling is used to perform surface rolling treatment on the target processing area of ​​the workpiece to introduce residual compressive stress on the surface layer.

[0015] Therefore, this invention employs the aforementioned fatigue-resistant manufacturing method for automotive transmission shafts based on surface texture technology. It identifies high-risk fatigue areas based on stress simulation and actual load spectrum, and matches differentiated texture morphology and arrangement directions to different failure modes such as bending fatigue and contact fatigue. This ensures that the stress dispersion and crack blocking effects of the texture precisely match the failure propagation path. Furthermore, it eliminates microcracks and burrs at the texture edges through abrasive flow passivation, transforming sharp edges into rounded corners to prevent the introduction of new fatigue sources during texture processing, thus guaranteeing the stability and reliability of the texture strengthening effect.

[0016] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0017] Figure 1 This is a flowchart (I) of the fatigue-resistant manufacturing method for automotive drive shaft systems based on surface texture technology in this invention. Figure 2 This is a flowchart (II) of the fatigue-resistant manufacturing method for automotive drive shaft systems based on surface texture technology in this invention. Detailed Implementation

[0018] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0019] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0020] Example 1 In this embodiment, the workpiece undergoes carburizing and quenching treatment as a whole, and the surface hardness is HRC≥58.

[0021] like Figure 1 As shown, a fatigue-resistant manufacturing method for automotive drive shaft systems based on surface texture technology includes the following steps: S1. Pre-treatment of workpiece: First, place the workpiece in an alkaline cleaning solution and ultrasonically clean it for 10 minutes to remove the cutting fluid and rust-preventive oil stains on the surface; then rinse it with deionized water and dry it with hot air at 80℃; finally, use a 1200-mesh ultrafine abrasive belt to perform fine polishing on the surface to be processed, and control the surface roughness Ra≤0.8μm.

[0022] S2. High-risk area identification and delineation: Establish a three-dimensional finite element model of the half-shaft, input the working condition parameters of rated torque, peak torque, and maximum radial runout, and perform stress simulation calculations under alternating loads. Based on the simulation results, delineate the continuous region where the equivalent stress amplitude is higher than 80% of the material fatigue limit as the target machining area, specifically including two shoulder transition fillet areas and the spline tooth meshing area.

[0023] S3. Zonal Adaptive Laser Surface Texture Processing: A nanosecond pulsed fiber laser is used for processing, with argon gas purging during the process to prevent surface oxidation. For the shoulder transition fillet area, where bending fatigue is predominant and principal stress is distributed axially, a continuously arranged circumferential microgroove texture is processed. The groove direction is perpendicular to the axial principal stress to prevent fatigue crack propagation axially. Laser parameters are set as follows: pulse width 100ns, repetition frequency 50kHz, scanning speed 200mm / s, laser power 25W; microgroove structure dimensions are: groove width 60μm, groove depth 15μm, and adjacent groove spacing 200μm. For the spline tooth meshing area, where contact fatigue and sliding wear are predominant, a micro-dimple texture with an equilateral triangular lattice arrangement is processed. The dimples are staggered along the sliding direction of the tooth surface, serving both oil storage and friction reduction purposes, as well as inhibiting crack initiation. The laser parameters were set as follows: pulse width 80ns, repetition frequency 80kHz, scanning speed 300mm / s, and laser power 20W; the micro-dimple structure dimensions were: diameter 40μm, depth 10μm, and center-to-center spacing of 100μm.

[0024] S4. Texture Edge Passivation Treatment: The entire half-shaft was polished using an abrasive flow polishing process with W7 silicon carbide abrasive, a polishing pressure of 1 MPa, and a polishing time of 8 minutes. After polishing, the radius of the texture edge fillet was sampled and tested, with an average value of 8 μm. There were no obvious burrs or microcracks on the edges.

[0025] S5. Performance Testing and Finished Product Output: X-ray diffraction was used to detect the residual stress on the surface of the target area. Three samples were selected for torsional fatigue testing, with a load of 1.2 times the rated torque. The average number of fatigue cycles was 1.2 × 10⁻⁶. 7 The finished product is obtained after meeting the design requirements and passing the inspection.

[0026] Example 2 like Figure 2As shown, the manufacturing method provided in this embodiment is basically the same as that in Embodiment 1, except that a surface pre-strengthening process is added before laser texturing.

[0027] Specifically, after completing the S2 high-risk area delineation, ultrasonic rolling equipment was used to roll all target processing areas. The rolling force was set to 800N, and the rolling head feed speed was 1mm / r. After rolling, the residual compressive stress on the surface was sampled and tested. Subsequently, laser texturing processing (S3) was performed, with the remaining process parameters being completely consistent with those in Example 1.

[0028] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A fatigue-resistant manufacturing method for automotive drive shaft systems based on surface texture technology, characterized in that, Includes the following steps: S1. Workpiece pretreatment: The automotive transmission shaft workpiece that has undergone machining and final heat treatment is cleaned and finished to remove surface oil, oxide layer and machining burrs, and the surface roughness Ra of the workpiece is controlled to be ≤0.8μm. S2. High-risk area identification and delineation: By combining finite element stress simulation with the actual working condition load spectrum of the transmission shaft system, identify and delineate at least one target processing area on the workpiece surface that is prone to fatigue failure. S3, Zone-adaptive laser surface texture processing: Using pulsed laser processing equipment, micro-texture units with corresponding morphological parameters and arrangement are processed according to the stress direction and failure mode of different target processing areas. S4. Texture edge passivation treatment: The surface of the workpiece after texture processing is polished by abrasive flow polishing process to eliminate burrs and microcracks at the edges of microtexture units and control the radius of the texture edge rounded corners to be ≥5μm. S5. Performance Testing and Finished Product Output: Sampling tests are conducted on the surface morphology, residual stress, and fatigue life of the workpiece. After passing the tests, the fatigue-resistant transmission shaft system is obtained.

2. The fatigue-resistant manufacturing method for automotive drive shafts based on surface texture technology according to claim 1, characterized in that: In step S1, the surface cleaning and finishing process sequentially employs alkaline solvent ultrasonic cleaning, deionized water rinsing, hot air drying, and ultra-fine abrasive belt polishing.

3. The fatigue-resistant manufacturing method for automotive drive shaft systems based on surface texture technology according to claim 2, characterized in that: The final heat treatment is carburizing and quenching, and the surface hardness of the workpiece after treatment is HRC≥58.

4. The fatigue-resistant manufacturing method for automotive drive shaft systems based on surface texture technology according to claim 1, characterized in that: In S2, the input conditions for the finite element stress simulation include the rated torque, peak torque, speed fluctuation, and radial runout of the transmission shaft system.

5. A fatigue-resistant manufacturing method for automotive drive shaft systems based on surface texture technology according to claim 4, characterized in that: The target machining area includes any one or more combinations of the shoulder transition fillet area, spline tooth surface meshing area, and universal joint raceway contact area.

6. The fatigue-resistant manufacturing method for automotive drive shaft systems based on surface texture technology according to claim 1, characterized in that: In step S3, the pulsed laser processing equipment uses a nanosecond pulsed fiber laser, and inert gas is used to purge and protect the processing area during the processing.

7. A fatigue-resistant manufacturing method for automotive drive shaft systems based on surface texture technology according to claim 6, characterized in that: The microtexture unit includes a microgroove texture arranged perpendicular to the principal stress direction in the region dominated by bending fatigue, and a micro-dimple texture arranged in a lattice pattern in the region dominated by contact fatigue. The cross-section of the microgroove texture is arc-shaped, and the cross-section of the micro-dimple texture is hemispherical.

8. The fatigue-resistant manufacturing method for automotive drive shaft systems based on surface texture technology according to claim 1, characterized in that: In step S4, the abrasive flow polishing uses silicon carbide abrasive particles.

9. A fatigue-resistant manufacturing method for automotive drive shaft systems based on surface texture technology according to claim 1, characterized in that: In step S5, the residual stress on the surface is detected by X-ray diffraction, and the fatigue life is detected by torsional fatigue testing machine.

10. A fatigue-resistant manufacturing method for automotive drive shaft systems based on surface texture technology according to claim 1, characterized in that: Between S2 and S3, there is also a surface pre-strengthening process: the target processing area of ​​the workpiece is subjected to surface rolling treatment using ultrasonic rolling process, and residual compressive stress is introduced into the surface layer.

Images