Spoke-Type Motor Rotor Core Segmentation for Flux Leakage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Spoke-type motors experience magnetic flux leakage and reduced torque density due to press-fit forces on the rotor's core, making it challenging to apply magnetic bridges effectively, especially in motors with ferrite permanent magnets and hollow rotors.
Innovation Solution
A rotor design featuring a first core part with a press-fit ring and multiple cores arranged circumferentially, supported by a third core that prevents deformation and minimizes magnetic flux leakage by separating its outer surface from the second cores, allowing for improved torque density and compatibility with ferrite permanent magnets and hollow rotors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a magnetic bridge is installed between the core and the shaft to reduce magnetic flux leakage, then magnetic flux leakage is reduced, but the device complexity increases and it becomes difficult to apply to spoke-type motors with ferrite permanent magnets and hollow rotors
Solution Approach 1:
The core is divided into multiple core parts (first core part, second core part, third core) arranged circumferentially around the shaft. This segmentation eliminates the need for a single large magnetic bridge while maintaining magnetic flux control, reducing device complexity and enabling application to spoke-type motors with ferrite permanent magnets and hollow rotors.
Solution Approach 2:
Magnetic bridges are selectively installed only at specific locations where core parts contact the shaft, rather than using a continuous magnetic bridge around the entire circumference. This local installation reduces the occupied area in the radial direction and simplifies the overall structure while still effectively controlling magnetic flux leakage.
2Strength
If the shaft is press-fitted into the core to provide mechanical support, then mechanical strength is improved, but the first core part becomes deformed and magnetic flux leakage increases
Solution Approach 1:
The core is segmented into multiple core parts that can be independently press-fitted onto the shaft. This segmentation distributes the press-fit force across multiple smaller contact areas, preventing deformation of individual core parts while maintaining mechanical strength. The segmented structure also creates multiple separate magnetic flux paths, reducing overall magnetic flux leakage.
Solution Approach 2:
Magnetic bridges serve as intermediary elements installed between the core parts and the shaft at contact points. These magnetic bridges mediate the press-fit connection, providing mechanical support while controlling magnetic flux leakage at the interface between the core and shaft, preventing both core deformation and magnetic flux leakage.
3Loss of energy
If an elongated magnetic bridge is used to reduce magnetic flux leakage, then magnetic flux leakage is reduced, but the area occupied in the radial direction increases making it difficult to apply to compact motor designs
Solution Approach 1:
The magnetic bridge is divided into multiple smaller magnetic bridges, each installed at specific contact points between core parts and the shaft. This segmentation reduces the total radial area occupied compared to a single elongated magnetic bridge, while still effectively controlling magnetic flux leakage through distributed contact points.
Solution Approach 2:
Magnetic bridges are installed only at local positions where core parts contact the shaft, rather than using a continuous elongated magnetic bridge. This local installation minimizes the radial area occupied by magnetic bridges while maintaining effective control over magnetic flux leakage at critical interfaces.
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 enhances torque density and prevents core deformation, enabling efficient magnetic flux transfer while maintaining a compact motor size, suitable for spoke-type motors with ferrite permanent magnets and hollow rotors.
Implementation Method 1
a first core part including a first press-fit ring into which the shaft is press-fitted
Implementation Method 2
a third core arranged inside the second cores, and installed to support the first press-fit ring
Implementation Method 3
The first connection rib may form a magnetic flux leakage path through which magnetic flux generated by the rotor is transferred toward the shaft
Implementation Method 4
The outer circumferential surface of the third core may be separated from inner ends of the second cores
Data Source
AI summary
A rotor of a motor apparatus may include: a shaft; a first core part including a first press-fit ring into which the shaft is press-fitted and a plurality of first cores arranged along the circumferential direction of the first press-fit ring so as to support magnets; a second core part including a plurality of second cores arranged along the circumferential direction of the shaft so as to face the first cores; and a third core arranged inside the second cores, and installed to support the first press-fit ring.