Single-phase outer-rotor motor and stator thereof
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Solution Overview
Problem
Single-phase outer-rotor motors face challenges with high cogging torque and noise due to the limited size of the stator and wide slot openings, which affect rotor stability and operation smoothness.
Innovation Solution
A stator core design with radially extending teeth, where tooth tips have cutting grooves that allow for outward tilting during winding and inward deformation to narrow slot openings, reducing cogging torque and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the stator size is limited due to the outer-rotor configuration, then the motor structure is compact and the load can be directly embedded in the rotor, but the slot opening width becomes large which increases cogging torque and affects rotor stability
Solution Approach 1:
The tooth tips are preliminarily tilted outwardly before winding assembly to enlarge the slot opening width, facilitating easier winding installation. After winding is completed, the tooth tips are deformed inwardly to narrow the slot opening and reduce cogging torque, thus resolving the contradiction between compact stator size and rotor stability
Solution Approach 2:
The tooth tip structure is designed to be dynamically adjustable: in the preliminary stage (before winding), the tooth tips are tilted outward to create larger slot openings for easier winding access; in the final stage (after winding), the tooth tips are deformed inward to narrow the slot openings and reduce cogging torque, allowing the structure to adapt to different operational requirements
2Ease of manufacture
If the slot opening width is enlarged to facilitate winding assembly, then the winding installation becomes easier, but the cogging torque increases and produces noises
Solution Approach 1:
The tooth tips are preliminarily tilted outwardly before winding assembly to enlarge the slot opening width, facilitating easier winding installation. After winding is completed, the tooth tips are deformed inwardly to narrow the slot opening and reduce cogging torque, thus resolving the contradiction between compact stator size and rotor stability
Solution Approach 2:
The slot opening width undergoes periodic change: first enlarged (outward tilting) to facilitate winding assembly, then narrowed (inward deformation) to reduce cogging torque and noise. This two-stage periodic action allows the structure to optimize for manufacturing ease first, then for operational performance
Data Source
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AI summary
A single-phase outer-rotor motor and a stator thereof are provided. The stator includes a stator core having a yoke and a number of teeth. Each tooth includes a tooth body and a toot tip. A winding slot is formed between each two adjacent tooth bodies. A slot opening is formed between each two adjacent tooth tips. The tooth tip protrudes beyond the tooth body. Inner surfaces of at least part of the tooth tips facing the stator are formed with cutting grooves such that a portion of the tooth tip outside the cutting groove is capable of being tilted outwardly to enlarge the slot opening and deformed inwardly to narrow the slot opening.