Motor Unit Cover Ribs Suppress Vibration Noise
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Solution Overview
Problem
Conventional motor units with annular members face noise issues due to vibration transmission from the casing to the annular member via the end plate, leading to potential noise generation.
Innovation Solution
The motor unit design includes a rotor, stator, bearing, housing, and an annular member with a cover that has ribs extending outward from the accommodation portion, which are fixed to the housing, effectively reducing vibration transmission to the annular member by providing a separate accommodation space and electrical connection for the ring brush, thus minimizing noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the annular member is accommodated in the end plate, then the structure is compact, but vibration is transmitted from the casing to the annular member via the end plate causing noise
Solution Approach 1:
The end plate is divided into a vibration-resistant portion and a vibration-prone portion, with the annular member accommodated in the vibration-resistant portion. This segmentation isolates the annular member from vibration transmission paths, reducing noise while maintaining compact structure.
Solution Approach 2:
A rib structure is introduced as an intermediary element between the casing and the annular member accommodation area. The rib extends from the vibration-resistant portion toward the vibration-prone portion, acting as a vibration barrier that blocks vibration transmission to the annular member.
2Object-affected harmful factors
If the annular member is provided independently from the bearing, then vibration transmission is reduced, but the device complexity increases
Solution Approach 1:
The vibration-resistant portion of the end plate is integrated with the bearing support structure, forming a unified component that simultaneously provides bearing support and vibration resistance. The annular member is accommodated in this integrated structure, reducing overall complexity while maintaining vibration isolation benefits.
Data Source
AI summary
A motor unit includes a bearing rotatably holding a shaft, and a housing accommodating a rotor, a stator, and the bearing. The housing has an opening, a cover closing the opening and fixed to the housing, and an annular member that has an annular shape when viewed from the axial direction and is provided independently from the bearing. The cover includes an accommodation portion accommodating the annular member, one or more ribs disposed radially outward of the accommodation portion when viewed from the axial direction, and one or more fixing points fixed to the housing. The one or more ribs extend outward from the accommodation portion. When viewed from the axial direction, for at least one of the ribs, the fixing point is formed on an extension line extending outward from the rib in a direction in which the rib extends.