Rotor Magnet Holder Layout for Lighter High-Torque Electric Machines
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Solution Overview
Problem
Conventional rotating electric machines, particularly outer and inner rotor types, face challenges in reducing the weight of the rotor while maintaining efficient torque density, as magnetic materials used in yokes have higher specific gravity than non-magnetic materials, leading to room for improvement in weight reduction.
Innovation Solution
The design incorporates a rotor with a disk-shaped end plate and an annular magnet unit where the magnet holder is made of a non-magnetic material, featuring a polar anisotropic magnet structure and a slotless stator configuration to enhance magnetic flux and torque density, and a flat conductor structure for the stator winding to reduce eddy currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If magnetic materials are used in the rotor yoke to maintain efficient torque density, then torque characteristics are improved, but the rotor weight increases due to higher specific gravity
Solution Approach 1:
The patent removes the traditional magnetic yoke structure from the rotor and replaces it with a non-magnetic material holder. The magnets are directly mounted on the non-magnetic holder, extracting the magnetic circuit function from the mechanical support structure. This separation eliminates the need for heavy magnetic materials in the rotor while maintaining the magnetic field generation capability through direct magnet mounting.
Solution Approach 2:
The patent changes the material parameter of the rotor holder from magnetic material to non-magnetic material, fundamentally altering the magnetic circuit path. This parameter change allows the magnetic flux to be conducted through the air gap and stator rather than through a magnetic yoke, thereby reducing rotor weight while maintaining torque density through optimized magnet arrangement and direct mounting.
2Strength
If a conventional rotor structure with magnetic yoke is used, then structural strength is maintained, but the device complexity and weight increase
Solution Approach 1:
The patent extracts the magnetic yoke component from the rotor structure, separating the mechanical support function from the magnetic circuit function. The non-magnetic holder solely provides mechanical support, while the magnetic circuit is formed through the air gap between magnets and stator, simplifying the overall rotor structure.
Solution Approach 2:
The non-magnetic holder serves multiple functions: it provides mechanical support for the magnets, maintains the radial positioning of magnets relative to the stator, and allows for simplified rotor assembly. This multi-functional design reduces the number of separate components needed while maintaining structural integrity.
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 configuration effectively reduces the rotor's weight while improving torque characteristics and magnetic flux distribution, leading to increased torque density and efficiency in the rotating electric machine.
Implementation Method 1
a magnet fixed to a peripheral surface on a stator side in the radial direction in the magnet holder and having an alternating polarity in a circumferential direction
Implementation Method 2
The magnet unit includes a cylindrical magnet holder... and a magnet fixed to a peripheral surface on a stator side in the radial direction
Implementation Method 3
The magnet holder is made of a non-magnetic material
Implementation Method 4
In the magnet, an orientation of an axis of easy magnetization on a q-axis is deviated from an orientation parallel to the q-axis
Data Source
AI summary
The rotating electric machine includes a stator having a stator winding and a rotor facing the stator in a radial direction. The rotor includes a carrier having a disk-shaped end plate section fixed to a rotating shaft and arranged coaxially with the rotating shaft, and an annular magnet unit arranged coaxially with the rotating shaft. The magnet has a cylindrical magnet holder whose one end in an axial direction is fixed to the end plate section, and a magnet fixed to a peripheral surface on a stator side in the radial direction in the magnet holder and having an alternating polarity in a circumferential direction. The magnet holder is made of a non-magnetic material. In the magnet, an orientation of an axis of easy magnetization on a q-axis is deviated from an orientation parallel to the q-axis.