Damping Coupler Spline Segmentation for Rattle Noise Reduction
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Solution Overview
Problem
The existing electronic steering apparatuses experience rattle noise due to gaps between serrations of the worm shaft and damping coupler, which are designed for assembly convenience but result in noise generation during torque load transmission.
Innovation Solution
A damping coupler is designed with a first and second spline, each having serrations that engage with the worm shaft serrations, and a molding surrounding these splines to minimize gaps, utilizing phase adjustments and protrusions to ensure close contact and reduce noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If gaps are formed between the serrations of the worm shaft and the damping coupler for assembly convenience, then assembly ease is improved, but rattle noise increases during torque load transmission
Solution Approach 1:
The damping coupler is divided into a first spline and a second spline that are coupled together. Each spline has serrations that engage with the worm shaft serrations. This segmentation allows the coupler to maintain assembly convenience while reducing gaps through the combined engagement of multiple splines.
Solution Approach 2:
The first and second splines are coupled together to form a unified damping coupler structure. This merging combines the engagement surfaces of both splines with the worm shaft, effectively reducing gaps and minimizing rattle noise while maintaining assembly feasibility.
2Device complexity
If a single damping coupler structure is used to simplify the design, then device complexity is reduced, but assembly precision and noise reduction capability are compromised
Solution Approach 1:
The damping coupler is segmented into first and second splines with distinct functions. The first spline engages with one set of worm shaft serrations while the second spline engages with another set, allowing for improved precision in serration engagement without excessive overall complexity.
Solution Approach 2:
Different regions of the damping coupler (first and second splines) have specialized structures optimized for their specific engagement functions. This local quality approach allows each spline to be precisely engineered for its specific serration engagement requirements.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively minimizes rattle noise by ensuring close engagement of serrations and using a rubber molding to attenuate vibrations, enhancing the operational silence and stability of the electronic steering apparatus.
Implementation Method 1
a damping coupler coupling the worm shaft with the motor shaft
Implementation Method 2
using a rubber molding to attenuate vibrations
Data Source
AI summary
Disclosed herein is a damping coupler of an electronic steering apparatus. The damping coupler includes a first spline having a first shaft hole such that a worm shaft is inserted therein, with a first serration being formed in the first shaft hole to engage with a serration of the worm shaft; a second spline coupled to a side of the first spline, and having a second shaft hole such that the worm shaft is inserted therein, with a second serration being formed in the second shaft hole to engage with a serration of the worm shaft; and a molding surrounding outsides of the first and second splines, and coupled to a motor shaft.