For the vibration and noise issues generated by the Rack-parallel Electric Power Steering (R-EPS) system under bumpy road conditions, this study analyzes the overall vibration transfer characteristics of the structure from the perspective of vibration transfer functions, identifying the primary frequency band of the abnormal noise. Meanwhile, modal analysis is employed to determine the correlation between the system's characteristic frequencies and its natural frequencies and mode shapes, confirming that the transfer function from the inner ball joint of the tie rod to the ball screw structure exhibits significant characteristic frequencies within the noise frequency band. To improve noise performance, based on the concept of transfer path optimization, rubber bushings were added to the mounting holes between the steering gear and the subframe to alter the stiffness and damping of the structural vibration transfer path. The effectiveness of this measure in optimizing the vibration transfer path was validated through CAE analysis and testing.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |