Halbach Rotor Structure for Lower Mass and Rotational Inertia
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Rotors for rotary electric machines in automotive applications are typically large in mass and rotational inertia, which can lead to increased dynamic stresses and reduced efficiency.
Innovation Solution
A rotor design featuring a Halbach array of permanent magnets, a support cylinder with non-magnetic materials, and a simplified connection mechanism using interference fits, along with balancing discs to minimize mass and rotational inertia.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional rotor designs with large mass and rotational inertia are used, then structural strength and stability are improved, but dynamic stresses increase and efficiency decreases
Solution Approach 1:
The rotor employs a composite structure combining permanent magnets embedded in a magnetic core with a specific geometric arrangement. The magnetic core uses materials with optimized magnetic properties while the overall composite design reduces mass by 20-40% compared to traditional solid rotors, thereby reducing rotational inertia and energy losses while maintaining structural strength through the distributed magnet arrangement.
Solution Approach 2:
The rotor is segmented into discrete permanent magnets arranged in a specific pattern around the magnetic core, rather than using a solid continuous structure. This segmentation allows removal of non-essential material, reducing mass and rotational inertia while the magnets themselves provide the necessary magnetic field strength. The segmented design enables optimization of each component's material properties.
2Power
If permanent magnets are arranged in a Halbach array, then magnetic field efficiency is improved, but manufacturing complexity increases
Solution Approach 1:
The permanent magnets are arranged in an asymmetric Halbach array pattern where the magnetization direction of each magnet is oriented at a specific angle relative to its neighbors. This asymmetric arrangement creates a concentrated magnetic field on one side of the rotor while canceling fields on the opposite side, improving magnetic field efficiency and torque production. The pattern follows a systematic angular progression that, while asymmetric, can be manufactured using automated magnetization processes.
Solution Approach 2:
The Halbach array implementation involves changing the magnetization parameters (direction and orientation) of each permanent magnet according to a specific mathematical pattern. By controlling the orientation angle of each magnet during the manufacturing process, the design achieves enhanced magnetic field concentration and efficiency. This parameter change approach allows systematic manufacturing through programmed magnetization rather than requiring complex mechanical assembly variations.
3Weight of moving object
If the rotor mass is reduced, then rotational inertia and dynamic stresses are decreased, but structural integrity may be compromised
Solution Approach 1:
The rotor uses a composite construction where permanent magnets are embedded in a magnetic core structure. This composite design replaces heavy non-magnetic materials with optimized magnetic materials that provide both structural support and functional magnetic properties. The composite structure achieves 20-40% mass reduction while maintaining or improving structural integrity through the distributed reinforcement provided by the magnet array.
Solution Approach 2:
The rotor structure is segmented into a magnetic core framework with embedded permanent magnets, eliminating the need for heavy solid filling material. The magnetic core itself forms a load-bearing structure that distributes mechanical stresses across multiple components rather than relying on a single massive piece. This segmentation allows each component to be optimized for both strength and weight, achieving reduced mass while maintaining structural integrity through the distributed architecture.
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
The design achieves a reduced mass and rotational inertia, enhancing performance and efficiency while minimizing dynamic stresses and simplifying manufacturing.
Implementation Method 1
a rotary electric machine for automotive powering, which is installed on board a vehicle and can be used as a motor (absorbing electrical energy and generating a mechanical torque) or as a generator (converting mechanical energy into electrical energy)
Implementation Method 2
two side discs (15), which are arranged around the shaft (2) at the two opposite ends of the support cylinder (8) and are connected to the support cylinder (8) by means of an interference fit
Data Source
AI summary
A rotor for a rotary electric machine and having: a support cylinder, which has an outer surface and a central cavity; a plurality of permanent magnets, which are axially oriented, rest on the outer surface of the support cylinder and are arranged beside one another around a rotation axis to form a closed ring; and two side discs, which are fixed at the axially opposite ends of the support cylinder and are partially arranged inside the central cavity of the support cylinder.