Rotor Core With Varying Magnetic Path Width
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Solution Overview
Problem
Existing rotors for rotary electric machines face challenges in reducing weight and inertia while maintaining torque and responsiveness, as the conventional design of permanent magnets and rotor cores does not effectively minimize weight and inertia.
Innovation Solution
The rotor design features a varying radial magnetic path width along the circumferential direction, achieved by alternating laminated core pieces with different magnetic path widths, which reduces weight and inertia by optimizing the distribution of magnetic flux and incorporating lightening holes and press-fit portions to minimize material usage and deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If lightening portions are formed in the rotor core to reduce weight and inertia, then weight and inertia are reduced, but the radial magnetic path width becomes non-uniform causing insufficient performance optimization
Solution Approach 1:
The patent applies local quality by making the magnetic path width vary intentionally in different circumferential regions. The outer circumferential portion has a first magnetic path width while the inner circumferential portion has a second magnetic path width that is different from the first. This localized variation optimizes both weight reduction and magnetic flux distribution, resolving the contradiction between uniformity and performance optimization.
2Speed
If the rotor core is made lighter to improve responsiveness, then inertia is reduced, but maintaining torque becomes more difficult
Solution Approach 1:
The patent changes the magnetic path width parameter in different circumferential regions to optimize both responsiveness and torque. By setting the outer circumferential portion with one magnetic path width and the inner circumferential portion with a different magnetic path width, the design achieves reduced inertia for better responsiveness while maintaining adequate torque through optimized magnetic flux distribution in each region.
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 the weight and inertia of the rotor, enhancing motor responsiveness and accuracy while preventing increases in cogging torque and deformation, thus improving the motor's performance and efficiency.
Implementation Method 1
a plurality of permanent magnets 4 which are each extended in an axial direction of the rotor core 2 and are fixed along an outer circumferential surface of the rotor core 2
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A rotor (1) for a rotary electric machine includes a rotor core (2) including a first core portion (20) having a plurality of core pieces (5, 6) joined together through caulking portions (2a) and a hollow first lightening portion (20a), and a second core portion (21) having a plurality of core pieces (7, 8) joined together through caulking portions (2a) and a press-fit portion (21 b). A radial magnetic path width of a ring-shaped outer circumferential portion formed by laminating the first core portion (20) and the second core portion (21) changes along a circumferential direction of the rotor core (2). Therefore, a weight and an inertia can be reduced.