Stepping Motor Casing With Integral Yoke Teeth
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Solution Overview
Problem
Conventional small stepping motors with an outer diameter of 8 mm or less face challenges in reducing production costs and maintaining torque characteristics due to the need for multiple yokes with uniform thickness, making it difficult to decrease the outer diameter and yoke tooth thickness simultaneously.
Innovation Solution
A casing design where yoke teeth are integrally formed on the inner surface with a varying thickness relative to the outer wall, allowing for increased yoke tooth thickness without increasing the outer wall thickness, thus enhancing torque performance and reducing component count.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the thickness of the outer wall of the casing is decreased to decrease the outer diameter of the stepping motor, then the outer diameter is reduced, but the thickness of the yoke teeth is also decreased, resulting in poor torque characteristics
Solution Approach 1:
The patent applies local quality by making the yoke teeth have a different thickness than the outer wall of the casing. Specifically, the yoke teeth are formed with a greater thickness than the outer wall, allowing the outer diameter to be reduced while maintaining sufficient yoke tooth thickness for adequate torque characteristics. This local differentiation of thickness resolves the contradiction between minimizing outer diameter and maintaining torque performance.
2Force
If four separate yokes with multiple yoke teeth are used, then the magnetic flux density is maintained, but the number of parts increases, leading to higher production costs and assembly complexity
Solution Approach 1:
The patent merges multiple separate yokes into a single integrated casing structure. The yoke teeth are directly formed on the inner surface of the casing as an integral structure, eliminating the need for separate yoke components. This merging reduces the number of parts and assembly steps while maintaining the magnetic flux density through proper design of the integrated yoke teeth configuration.
3Ease of manufacture
If the thickness of the outer wall is made equal to the thickness of the yoke teeth to simplify manufacturing, then the manufacturing process is simplified, but the outer diameter cannot be sufficiently decreased
Solution Approach 1:
The patent resolves this contradiction by applying local quality - the yoke teeth are formed with a different (greater) thickness than the outer wall of the casing. This allows the outer wall to be made thin to reduce outer diameter, while the yoke teeth maintain sufficient thickness for magnetic performance. The differential thickness is achieved through integral forming processes that can create varying wall thicknesses in different regions of the same component.
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 design enables higher torque performance in small stepping motors while reducing production costs and simplifying assembly, minimizing defects by allowing for a smaller outer diameter without compromising torque characteristics.
Implementation Method 1
The magnetic flux of the magnet 220 passes through the yoke teeth 120a of the first stator 100 alternately disposed, and the yoke teeth 120 of the second stator 100a alternately disposed.
Data Source
AI summary
Disclosed is a structure of a casing of a small stepping motor having an outer diameter of 8 mm or less, in which yoke teeth are integrally formed on the inner surface of the casing, and the thickness of the outer wall of the casing is different from the thickness of each of the yoke teeth. The casing of a small stepping motor includes yoke teeth integrally formed on an inner surface of the casing, in which a thickness of an outer wall of the casing is different from a thickness of the yoke tooth.