Investigation of Spline-Induced Excitation Forces in Electric Drive Units via Flexible Multibody Dynamic Simulation Hyundai Mobis

Format:

Book

Conference/Event

Author/Creator:

Kim, Dong-Jun, author.

Hwang, Seung Gyu, author.

Kim, Donghee, author.

Kim, Seon Hyeong, author.

Lee, SangHan, author.

Grant, George, author.

Halse, Christopher, author.

Conference Name:

14th International Styrian Noise, Vibration & Harshness Congress: The European Automotive Noise Conference (2026-06-17 : Graz, Austria)

Language:

English

Subjects (All):

Electric drives.

Splines.

Vehicle dynamics.

Local Subjects:

Electric drives.

Splines.

Vehicle dynamics.

Physical Description:

1 online resource

Place of Publication:

Warrendale, PA SAE International 2026

Summary:

This study investigates the NVH characteristics of the spline coupling that connects the motor and reducer shafts in an electric drive unit, using flexible multibody dynamics simulations. Focusing on the source stage of the NVH analysis process, the excitation force magnitude and spline trajectory are examined under various spline design conditions. The study compares spline fit types (side fit vs. major fit), clearance vs. interference conditions, and variations in tooth number and module size. This study analyzes the overall behavior of spline excitation forces under various design conditions, complementing prior research focused mainly on specific causes or manufacturing improvements. Side fit splines exhibit lower first-order excitation forces compared to major fit splines, but significantly higher excitation forces at higher orders. This leads to increased spline trajectory amplitude and amplified whirling of the input shaft. Since the input gear is directly coupled to the input shaft, this whirling behavior increases the gear center-distance variation, which in turn amplifies the cumulative pitch error. In particular, clearance fit conditions result in greater higher-order excitation forces and gear eccentricity than interference fits. Major fit splines, on the other hand, show more stable trajectories and lower higher-order excitation forces, minimizing their impact on the overall system. The analysis of tooth number variation reveals that increasing the number of teeth reduces first-order excitation forces while increasing higher-order components, indicating that force distribution within the spline can be tuned. Tooth number adjustment does not affect the rest of the system, suggesting it is a practical strategy for achieving desired NVH characteristics. In conclusion, spline design parameters such as fit type and tooth number significantly influence the magnitude and directional behavior of excitation force, leading to system-level phenomena

Notes:

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