Characterization of Axial Geometric Variations and Dimensional Deviation Analysis of High-Speed Ball Bearings for New Energy Vehicles Using X-Ray Computed Tomography

As new energy vehicle drive motors develop toward higher rotational speeds and power levels, a more comprehensive characterization of the geometric condition of high-speed ball bearings is increasingly required, while conventional single-section measurements have difficulty capturing continuous axial geometric variations. To characterize continuous axial geometric variations in high-speed ball bearings for new energy vehicle drive motors and explore whether these variations exhibit trends consistent with vibration responses, four typical bearing models were investigated using X-ray computed tomography (XCT), reconstruction, and dimensional extraction. Equivalent inner and outer diameters were obtained from consecutive sections within the selected axial profile segment. The mean values of the equivalent inner and outer diameters were used to represent the dimensional level, while the standard deviation and range were used to quantify the axial fluctuations. The results showed that the equivalent inner and outer diameters of different bearing samples exhibited different degrees of axial variation within the selected axial profile segments. Meanwhile, the mean equivalent inner and outer diameters measured by XCT differed from the corresponding nominal dimensions. Further comparison showed that, within the current sample set, no stable correspondence was observed between the axial variation descriptors of the XCT-derived equivalent inner and outer diameters and the vibration test results. XCT can nondestructively acquire geometric information from consecutive axial sections and quantitatively characterize equivalent inner and outer diameter fluctuations, complementing single-section roundness measurement and providing theoretical guidance for surface-quality evaluation and manufacturing-process improvement.