Motor Sensing Unit Fixing Plate Press-Fit Assembly
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Solution Overview
Problem
The existing electronic power steering system (EPS) motor's sensing magnet and plate coupling structure is prone to separation due to temperature changes, mechanical stress, and external forces, leading to reliability issues.
Innovation Solution
A sensing unit is designed where the sensing plate and magnet are directly fixed to the rotating shaft using a fixing plate member that press-fits onto the shaft, eliminating adhesive bonding and enhancing structural reliability by providing a strong, non-magnetic fixing plate that covers the sensing magnet's surface and uses a coupling member to secure it.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If adhesive bonding is used to couple the sensing magnet with the sensing plate, then the assembly process is simplified, but the reliability deteriorates due to separation under temperature changes, mechanical stress, and external forces
Solution Approach 1:
The patent replaces the chemical bonding method (adhesive) with a mechanical coupling system consisting of a sensing plate assembly that integrates the sensing magnet and plate into a unified mechanical structure. This mechanical integration eliminates reliance on adhesive bonds that fail under environmental stress, while maintaining assembly simplicity through the pre-integrated design of the sensing plate assembly.
2Ease of manufacture
If adhesive bonding is used to couple the sensing plate with the rotating shaft, then the installation process is simplified, but the reliability deteriorates due to separation under temperature changes, mechanical stress, and external forces
Solution Approach 1:
The patent replaces adhesive bonding between the sensing plate and rotating shaft with a direct mechanical coupling structure. The sensing plate assembly is designed to be directly mounted to the rotating shaft through mechanical means such as keyways, set screws, or interference fits, eliminating the adhesive layer that separates under thermal and mechanical stress while maintaining installation simplicity through standardized mechanical interfaces.
3Device complexity
If a bonding coupling structure is used for the sensing magnet and plate, then the manufacturing complexity is reduced, but the structural reliability worsens due to separation phenomena under abnormal bonding conditions
Solution Approach 1:
The patent merges the sensing magnet and sensing plate into a single integrated sensing plate assembly. The sensing magnet is embedded within or directly coupled to the sensing plate as a unified component, eliminating the separate bonding interface between magnet and plate. This integration reduces the number of coupling joints from two (magnet-plate and plate-shaft) to one (assembly-shaft), thereby reducing manufacturing complexity while simultaneously eliminating separation failure modes.
Data Source
AI summary
A structure of a motor which is capable of enhancing a sensing efficiency and a structural reliability is provided. Particularly, a sensing unit for a motor and a motor including the sensing unit which has a rotating shaft, a sensing plate press-fitted in a structure of passing through the rotating shaft, a sensing magnet disposed on the sensing plate, and a fixing plate coupled to a center of the rotating shaft by a coupling member and disposed in a structure of covering an exposed surface of the sensing magnet.