Rotor Pole Piece Recesses for Lower Cogging Torque
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional rotors exhibit high cogging torque, which affects their efficiency and performance.
Innovation Solution
The rotor design incorporates a plurality of magnets arranged in a circumferential direction with magnetic pole pieces that have recessed parts extending in the radial direction, reducing the contact area and minimizing magnetic flux interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional rotor design with magnets radially arranged around output shaft is used, then motor structure is simple, but cogging torque is high
Solution Approach 1:
The magnetic pole pieces are given different local qualities through the provision of recessed parts at specific locations. These recessed parts create localized variations in magnetic flux distribution, allowing different regions of the magnetic pole pieces to have different magnetic characteristics. This local quality differentiation reduces cogging torque by optimizing the magnetic flux path between adjacent magnets while maintaining the overall simple motor structure.
Solution Approach 2:
The invention introduces a new dimensional feature by adding recessed parts that extend in the radial direction on the lateral surfaces of magnetic pole pieces. This creates a three-dimensional magnetic flux distribution pattern rather than a simple two-dimensional arrangement, allowing magnetic flux to be controlled in multiple directions and reducing cogging torque without complicating the basic motor structure.
2Object-generated harmful factors
If magnetic pole pieces with recessed parts extending in radial direction are added, then cogging torque is reduced, but device complexity increases
Solution Approach 1:
The magnetic pole pieces are segmented by introducing recessed parts that divide the lateral surfaces into distinct regions. This segmentation allows independent optimization of different magnetic flux paths, reducing cogging torque by creating controlled magnetic flux barriers. The segmentation is achieved through simple geometric modifications rather than adding separate components, thus limiting the increase in device complexity.
Solution Approach 2:
The invention modifies the geometric parameters of magnetic pole pieces by adding recessed parts with specific dimensions and positions. By changing these physical parameters (depth, width, position of recesses), the magnetic flux distribution is optimized to reduce cogging torque. This parameter-based approach allows systematic control of cogging torque reduction while maintaining manufacturing feasibility and limiting structural 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 effectively reduces cogging torque by minimizing magnetic flux leakage and improving rotational stability, enhancing motor performance.
Implementation Method 1
magnetic pole pieces, in which, in the circumferential direction, the magnetic pole pieces are in contact with two adjacent magnets of the plurality of magnets, and lateral surfaces of the magnetic pole pieces extending in the circumferential direction are provided with recessed parts extending in a radial direction
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A rotor (6) includes a plurality of magnets (64) arranged in a circumferential direction (C) and a plurality of magnetic pole pieces (622). In the circumferential direction (C), the magnetic pole piece (622) is in contact with two adjacent magnets (64) of the plurality of magnets (64). A lateral surface of the magnetic pole piece (622) extending in the circumferential direction (C) includes a recessed part (622c) extending in a radial direction.