Spoke-Magnet Rotor Structure for Compact High-Torque Electric Tools
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Solution Overview
Problem
Existing electric tools with motors face challenges in reducing the diameter of the rotor while maintaining torque and preventing deformation due to increased centrifugal forces and moment of force requirements.
Innovation Solution
The electric tool incorporates a rotor with a circular cylindrical rotor core and a large number of permanent magnets arranged as spokes around the center, reducing the rotor's diameter by narrowing the interval between magnets, and includes high magnetic resistance portions and voids to enhance torque and mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the rotor diameter is reduced, then the motor size is compacted, but the torque and mechanical strength decrease
Solution Approach 1:
The rotor is segmented into multiple permanent magnets arranged in a specific pattern around the rotor core, with each magnet contributing to the overall torque generation. This segmentation allows the rotor to maintain high torque output despite reduced diameter by optimizing the distribution and arrangement of magnetic elements.
Solution Approach 2:
The patent applies local quality by creating high magnetic resistance portions at specific locations (between adjacent permanent magnets) and voids at other specific locations (radially outward from the rotor core). This localized modification of magnetic properties optimizes the magnetic flux distribution, enhancing torque generation in the compact rotor structure.
2Volume of moving object
If the rotor diameter is reduced, then the motor size is compacted, but the risk of deformation increases due to centrifugal forces
Solution Approach 1:
The patent introduces high magnetic resistance portions and voids at strategically selected locations within the rotor structure. The high magnetic resistance portions are positioned between adjacent permanent magnets to control flux leakage, while voids are created radially outward to reduce mass and centrifugal forces. This localized structural modification maintains mechanical strength while enabling compact dimensions.
Solution Approach 2:
The rotor employs a composite structure combining permanent magnets, magnetic resistance portions (made of magnetic material), and voids within the rotor core. This composite design optimizes both mechanical strength and magnetic performance, allowing the rotor to withstand centrifugal forces while maintaining compact size.
3Volume of moving object
If permanent magnets are arranged closely to reduce diameter, then the rotor is compacted, but magnetic flux leakage increases
Solution Approach 1:
The patent addresses magnetic flux leakage by introducing high magnetic resistance portions at specific locations between adjacent permanent magnets. These localized high resistance regions act as magnetic barriers, controlling and directing the magnetic flux paths to prevent leakage, thereby maintaining efficient magnetic coupling despite the compact arrangement of magnets.
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 diameter while maintaining torque and mechanical strength, reducing the risk of deformation and increasing the motor's efficiency.
Implementation Method 1
a rotor (5) including: a rotor core (6) having a circular cylindrical shape; a plurality of permanent magnets (7); and an output shaft (51) held inside the rotor core (6). The plurality of permanent magnets (7) are arranged as spokes around a center (C1) of the rotor core (6)
Implementation Method 2
a motor (1) including a stator core (20) and a rotor (5). The rotor (5) rotates with respect to the stator core (20)
Implementation Method 3
the rotor (5) includes six or more permanent magnets (7) as the plurality of permanent magnets (7)
Data Source
AI summary
An electric tool includes a motor. The motor includes a stator core and a rotor. The rotor rotates with respect to the stator core. The rotor includes: a rotor core having a circular cylindrical shape; a plurality of permanent magnets; and an output shaft. The output shaft is held inside the rotor core. The plurality of permanent magnets are arranged as spokes around a center of the rotor core.