Rotor Magnet Spacing Layout for Torque Ripple Reduction
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Solution Overview
Problem
Conventional rotary electric machines face challenges in efficiently reducing torque ripple due to complex structures and increased costs associated with using multiple coil types or special processing of the rotor and stator.
Innovation Solution
The rotary electric machine features a rotor with magnets arranged such that their separation distances along the circumferential direction alternate between poles, resulting in alternating 'large' and 'small' magnetisms, which overlap to suppress torque fluctuations and reduce ripple without the need for multiple coil types or special processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If multiple types of coils are used or special processing is applied to the rotor and stator to reduce torque ripple, then torque ripple reduction is achieved, but the structure becomes complicated and cost increases
Solution Approach 1:
The invention applies local quality by varying the separation distances between magnets in specific poles while keeping other poles unchanged. Specifically, first poles have a first separation distance between adjacent magnets, while second poles have a second separation distance that differs from the first. This localized variation in magnet spacing creates differential magnetic field distributions that reduce torque ripple without requiring complex overall structural changes or multiple coil types.
2Object-generated harmful factors
If multiple types of coils are used or special processing is applied to the rotor and stator to reduce torque ripple, then torque ripple reduction is achieved, but manufacturing cost increases
Solution Approach 1:
The invention reduces manufacturing cost by implementing local quality changes only where necessary - specifically in the magnet arrangement of certain poles. The rotor uses two types of poles (first and second poles) with different magnet separation distances, but this differentiation is localized rather than requiring complete redesign of all components. This approach avoids the need for multiple coil types and extensive special processing, thereby controlling manufacturing costs while achieving torque ripple reduction.
3Ease of manufacture
If uniform separation distances are used between magnets in all poles, then manufacturing is simplified, but torque ripple cannot be efficiently reduced
Solution Approach 1:
The invention applies asymmetry by deliberately creating non-uniform magnet separation distances in specific poles. While first poles maintain a first separation distance between adjacent magnets, second poles are designed with a second separation distance that is intentionally different. This asymmetric arrangement in alternating poles creates a magnetic field distribution pattern that reduces torque ripple, demonstrating that controlled asymmetry can improve performance without completely sacrificing manufacturing simplicity.
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 torque ripple while maintaining a simple structure, avoiding cost increases and enhancing operational stability by overlapping 'large' and 'small' maximum torques at adjacent magnetic poles, thus minimizing torque fluctuations during rotation.
Implementation Method 1
a rotor (e.g., an after-mentioned rotor 3) of a rotary electric machine (e.g., an after-mentioned rotary electric machine 1 or 10) which is rotatably disposed in a stator (e.g., an after-mentioned stator 2), the rotor including two or more magnets (e.g., after-mentioned magnets 41 or 42) arranged per pole
Implementation Method 2
magnetisms of magnets of magnetic poles adjacent to each other in the circumferential direction of the rotor are alternately provided to be 'large', 'small'
Data Source
AI summary
Provided are a rotor of a rotary electric machine, and a rotary electric machine, in which torque ripple can be efficiently reduced with a simple configuration. In the rotor of the rotary electric machine which is rotatably disposed in a stator, and the rotary electric machine including the stator, and the rotor rotatably disposed in the stator, two or more magnets are arranged per pole, and arranged such that separation distances, between the two or more magnets per pole along a circumferential direction of the rotor, alternately vary every pole along the circumferential direction of the rotor.