Spoke-Type PM Rotor Bridge Holes for Flux Leakage Reduction
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Solution Overview
Problem
Spoke type permanent magnet motors experience significant magnetic flux leakage, leading to increased manufacturing costs and reduced miniaturization due to the need for more permanent magnets to maintain power output.
Innovation Solution
The motor design incorporates a sleeve with axial holes, rotor cores, bridges with holes to block magnetic flux paths, and a molding unit to connect the sleeve and rotor cores, reducing magnetic flux leakage by creating internal spaces and blocking unnecessary flux paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the spoke type permanent magnet motor uses a support to arrange permanent magnets radially, then high torque and high power are generated, but magnetic flux leaks through the support toward the motor shaft
Solution Approach 1:
The patent extracts and removes the harmful magnetic flux path by introducing holes through the bridges that connect the rotor core to the support. These holes block the leakage flux from traveling through the support to the motor shaft, effectively taking out the harmful flux path while preserving the useful magnetic circuit for torque generation.
Solution Approach 2:
The patent introduces a porous structure (holes) in the bridge components to control magnetic flux behavior. The holes create intentional voids that block the leakage flux path through the support, while the remaining solid material maintains the structural integrity and magnetic circuit functionality needed for high power output.
2Power
If more permanent magnets are used to compensate for magnetic flux leakage, then power output is maintained, but manufacturing cost increases
Solution Approach 1:
Instead of adding more permanent magnets to compensate for flux leakage, the patent removes the harmful flux path through holes in the bridges. This approach maintains power output by preserving the efficiency of existing magnet usage, thereby avoiding the increased manufacturing costs associated with additional magnets.
3Power
If more permanent magnets are used to compensate for magnetic flux leakage, then power output is maintained, but motor size increases
Solution Approach 1:
The patent eliminates the need for additional permanent magnets by removing the harmful flux leakage path through holes in the bridge structure. This maintains power output with the existing magnet count, enabling motor miniaturization rather than increasing motor size.
4Strength
If bridges connect the sleeve and rotor cores, then structural integrity is maintained, but magnetic flux leaks through the bridges
Solution Approach 1:
The patent introduces holes through the bridge components to block magnetic flux leakage while maintaining structural integrity. The holes create a porous configuration that interrupts the magnetic flux path through the support, yet the remaining solid material preserves the mechanical strength needed to hold the rotor cores and permanent magnets in place.
Solution Approach 2:
The patent applies local quality modification by selectively positioning holes in specific regions of the bridges where flux leakage occurs. This localized modification blocks harmful flux paths in critical areas while maintaining the overall structural integrity and magnetic circuit functionality of the rotor assembly.
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 minimizes magnetic flux leakage, reducing the number of permanent magnets required for the same power output, thereby lowering manufacturing costs and enabling more compact motor designs.
Implementation Method 1
a plurality of holes respectively corresponding to the plurality of bridges, wherein each hole of the plurality of holes extends through the corresponding bridge of the plurality of bridges so as to block a connection between a first end portion and a second end portion of the bridge
Data Source
AI summary
A motor comprising a stator; and a rotor surrounded in a circumferential direction of the rotor by the stator, wherein the rotor includes: a sleeve including an axial hole extending in a first direction, a plurality of rotor cores spaced apart from each other around the sleeve in the circumferential direction of the rotor, a plurality of permanent magnets respectively arranged, between each two adjacent rotor cores of the plurality of rotor cores, a plurality of bridges respectively corresponding to the plurality of rotor cores, a plurality of holes respectfully corresponding to the plurality of bridges, and a molding unit disposed between the sleeve and the plurality of rotor cores, wherein the molding unit connects the sleeve to the plurality of permanent magnets and the plurality of rotor cores