Polygonal Motor Frame with Asymmetric Core Insertion
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Solution Overview
Problem
Existing motor frame structures face challenges in achieving a perfect circular shape for the inner stator surface, leading to uneven magnetic energy distribution and increased cogging torque due to manufacturing factors such as variation in armature core dimensions and assembly precision.
Innovation Solution
A motor frame structure with a polygonal outer periphery and circular inner periphery, where the armature core is inserted at a specific angle to disperse uneven stress, defined by the number of angles based on the frame's thickness peaks and the number of slots, to reduce cogging torque by optimizing the insertion angle and core configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional circular frame structure is used, then the inner stator surface can be made circular, but manufacturing variations cause uneven stress distribution and increased cogging torque
Solution Approach 1:
The patent applies asymmetry by changing the frame's outer periphery from a conventional circular shape to a polygonal shape with a specific number of sides. This asymmetric geometric modification transforms how stress is distributed throughout the structure, converting the harmful uneven stress concentration that occurs in circular frames into a more uniform stress pattern that reduces cogging torque while maintaining manufacturing feasibility
2Ease of manufacture
If the armature core is inserted at reference positions, then assembly is simplified, but cogging torque increases due to symmetric pole-slot alignment
Solution Approach 1:
The patent employs asymmetry by defining specific insertion angle ranges that deviate from the conventional symmetric reference positions. The polygonal frame geometry combined with controlled angular deviation creates an asymmetric magnetic energy distribution that suppresses cogging torque while maintaining practical assembly through defined angular tolerances
Solution Approach 2:
The patent applies parameter changes by modifying the insertion angle of the armature core relative to the frame. Instead of using fixed reference positions, the invention specifies angular ranges (e.g., 0° to 15° or 30° to 45° depending on pole and slot counts) that optimize the magnetic energy distribution and reduce cogging torque while remaining manufacturable
3Stability of the object's composition
If the number of frame angles is increased, then stress distribution improves, but device complexity increases
Solution Approach 1:
The patent applies parameter changes by establishing specific relationships between the number of frame angles and the pole/slot configuration. The number of sides in the polygonal frame is determined by formulas involving the pole count P and slot count S (e.g., number of sides = P/2 or S/3), creating an optimized balance between stress distribution and manufacturing complexity for each motor design
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
This approach allows for a more ideal perfect circular shape of the inner stator surface, stabilizing cogging torque and reducing manufacturing-related cogging torque factors by dispersing uneven stress and optimizing the armature core's insertion angle.
Implementation Method 1
inserting the armature core into the frame at a specific angle in order to disperse uneven stress received from the frame
Implementation Method 2
obtaining a more ideal perfect circular shape for an inner peripheral surface of the armature core, thereby reducing a 'manufacturing factor' being one of factors of occurrence of cogging torque
Data Source
AI summary
In a frame structure of a motor, when the number of angles of a frame is 4M (M is a natural number, and M≥1), and the number of slots of an armature core is 6N (N is a natural number, and N≥1), the armature core is inserted into the frame in such a manner as to form a variation θ within a predetermined range in a circumferential direction between a reference line that is orthogonal to two opposing sides of the frame and passes through a rotation axis of the frame, and a straight line linking magnetic poles symmetric about a point with respect to the rotation axis.