Electric Motor Yoke Flat Sections and Magnet Placement
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Solution Overview
Problem
Existing electric motors face limitations in miniaturization due to the thickness of permanent magnets, inefficiencies in winding processes, and increased manufacturing costs, as well as challenges in reducing size and weight while maintaining performance and preventing rotation imbalance.
Innovation Solution
The electric motor design features a cylindrical yoke with flat sections, rare earth element permanent magnets positioned away from these sections, a deformed armature core with tilted teeth, and a distributed winding method to optimize space usage and balance, allowing for reduced size and weight while maintaining performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If ring-shaped or tile-shaped permanent magnets are disposed at an inner circumferential surface of the cylindrical yoke, then the electric motor can achieve high magnetic force and miniaturization, but the size of the appearance is restricted by the processing thickness of the permanent magnet, limiting further miniaturization
Solution Approach 1:
The patent changes the shape of permanent magnets from ring-shaped or tile-shaped to flat plate-shaped, and changes the arrangement from inner circumferential surface to positions away from flat sections of the cylindrical section. This dimensional change allows the motor size to be reduced without being constrained by the thickness of the permanent magnets, as they are now arranged in a different spatial configuration that does not require thick processing.
2Stability of the object's composition
If the winding is wound between slots disposed at predetermined intervals using distributed winding method, then the coil can be arranged in slots, but the coil wound later is disposed further outside in radial direction, generating ineffective space and causing unstable position and state of the coil, resulting in rotation imbalance
Solution Approach 1:
The patent applies asymmetry by making the slot shapes different from each other. Specifically, slots adjacent to flat sections have different shapes compared to other slots. This asymmetric slot design allows for optimized winding arrangement that eliminates ineffective spaces and ensures stable coil positioning, preventing rotation imbalance while maximizing space utilization.
3Volume of moving object
If the shaft-side bottom surface of the slot is formed substantially along the outer circumferential side line of the armature core, then the shaft-side end section of the coil can come in contact with the slot surface, preventing useless space and generation of instability, but this configuration may increase manufacturing complexity
Solution Approach 1:
The patent applies local quality by making slot shapes different depending on their position. Slots adjacent to flat sections have specific configurations optimized for coil contact and space utilization, while other slots have different configurations. This localized optimization ensures maximum space utilization and stable coil positioning without requiring all slots to have complex identical shapes, thus managing manufacturing complexity.
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 miniaturization of the electric motor, reduces manufacturing time and costs, and prevents rotation imbalance by optimizing the placement of permanent magnets and winding configuration, resulting in improved space efficiency and performance.
Implementation Method 1
When the current is supplied to the winding, a magnetic field is formed, and the armature is rotated by a magnetic attractive force or repulsive force generated between the magnetic field and the permanent magnet
Implementation Method 2
the armature is rotated by a magnetic attractive force or repulsive force generated between the magnetic field and the permanent magnet
Data Source
AI summary
An electric motor includes a yoke having a cylindrical section, two pairs of permanent magnets disposed at an inner circumferential surface of the cylindrical section to oppose each other, and an armature rotatably supported further inside in a radial direction than the permanent magnets, wherein at least a pair of first flat sections opposing each other in the radial direction are formed at the cylindrical section, and the permanent magnets are disposed at positions distant from the first flat sections.