Permanent Magnet Motor Rotor Bridge Thickness Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional permanent-magnet motors used in applications like electric power steering systems generate operational sound and vibration when driven, causing discomfort, despite reduced torque ripple and cogging torque.
Innovation Solution
A permanent-magnet motor design featuring a stator core with alternating teeth and slots, a rotor core with through-holes and expansion portions, and embedded magnets, where the bridge portion between magnetic-field poles has a smaller thickness than the rest of the rotor core, and phase difference control is applied to the armature coils to reduce magnetic flux and torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If permanent magnets are embedded in the rotor core, then magnetic-field poles are formed, but operational sound and vibration are generated
Solution Approach 1:
The bridge portion acts as an intermediary structure between adjacent permanent magnets. By designing the bridge portion with small-thickness and large-thickness portions, it mediates the magnetic flux interaction between magnets, preventing direct flux leakage and reducing the operational sound and vibration generated by magnet interactions
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 suppresses sound and vibration generated during motor operation by optimizing magnetic flux distribution and torque characteristics, enhancing operational comfort.
Implementation Method 1
a plurality of permanent magnets that are embedded in the rotor core and form a plurality of magnetic-field poles in the rotor core
Implementation Method 2
an armature coil that includes a conductor inserted into the slot and mounted in the stator core
Data Source
Figure 1~2
Figure 3
Figure 4A~4B
AI summary
A permanent-magnet motor includes a through-hole expansion portion provided in a through-hole for inserting a permanent magnet into the rotor core of a permanent-magnet motor, and a bridge portion that surrounds adjacent through-hole expansion portions and forms part of the outer circumferential surface of the rotor core; the bridge portion has a small-thickness portion that is formed to be smaller than that of a portion, other than the bridge portion, of the rotor core.