Motor Brush Movement Restricting Structure
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Solution Overview
Problem
Existing motor designs with brush holders made of resin or bent metal materials face limitations in suppressing brush looseness due to clearance issues and working accuracy constraints, leading to performance degradation and reduced motor life.
Innovation Solution
A motor with a brush and a movement restricting structure that includes a holder for radial movement and a circumferentially restricting part with a punching-formed passing port, which enhances dimensional accuracy and stiffness, reducing brush looseness and improving productivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a brush holder is made of resin or bent metal material, then the structure is simple and easy to manufacture, but the working accuracy is limited and relatively large clearance is caused between the brush and the brush holder, leading to brush looseness
Solution Approach 1:
The brush holder is divided into two separate parts: a holder body (made of resin or bent metal) and a circumferentially restricting part (made of rigid material with high dimensional accuracy). This segmentation allows each part to be optimized for its specific function - the holder body for ease of manufacture and the restricting part for precision, thereby resolving the contradiction between ease of manufacture and manufacturing precision.
Solution Approach 2:
The brush holder combines materials with different properties: the holder body uses easily manufacturable materials (resin or bent metal) while the circumferentially restricting part uses rigid materials with high dimensional accuracy. This composite approach allows the structure to benefit from both ease of manufacture and high manufacturing precision, eliminating brush looseness while maintaining manufacturing simplicity.
2Reliability
If a pressing piece with spring property is used to press the brush toward the side wall, then some looseness is suppressed, but there is a limit in suppressing the looseness due to the clearance between the brush and the brush holder
Solution Approach 1:
The brush holder is segmented into a holder body and a separate circumferentially restricting part. The restricting part is specifically designed with high dimensional accuracy to minimize clearance, directly addressing the limitation of spring-based pressing pieces that cannot fully compensate for manufacturing tolerances.
Solution Approach 2:
The invention changes the dimensional parameters of the circumferentially restricting part to achieve high precision fit with the brush. By controlling the clearance between the brush and the restricting part to be 0.01 to 0.05 mm, the system achieves superior reliability compared to spring-based solutions, while the restricting part itself is designed for ease of manufacture through punching or pressing processes.
Data Source
AI summary
A motor includes a brush configured to contact a commutator and a movement restricting structure configured to restrict a movement of the brush. The movement restricting structure has: a carbon holder for housing the brush while permitting a movement of the brush in the commutator radial direction; and a circumferentially restricting part for restricting a movement of the brush in the commutator circumferential direction. The circumferentially restricting part has a passing port formed by punching, through which the brush passes.