Embedded Permanent Magnet Rotor with V-Shaped Holes
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Solution Overview
Problem
The existing embedded permanent magnet type rotating electric machines face challenges such as complex manufacturing processes due to multiple rotor steel materials with different shapes, restricted design flexibility, increased computation load for magnetic field and strength calculations, magnetic flux leakage, poor ventilation, uneven centrifugal stress, and difficulty in increasing torque due to residual stress and magnetic resistance.
Innovation Solution
The design features magnet embedding holes that communicate with the rotor outer periphery, eliminating the need for side bridges and allowing for the use of a single type of steel plate, reducing assembly residual stress, and incorporating q-axis projections and positioning projections to enhance torque and stability, while the outer peripheral edge has a curvature radius smaller than the distance to the outermost peripheral portion to reduce torque pulsations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If multiple types of rotor steel materials are used to reduce magnetic flux leakage, then magnetic flux leakage is reduced, but device complexity and manufacturing complexity increase
Solution Approach 1:
The patent uses a single type of rotor steel material for all rotor plates instead of alternating between different types. This homogeneous approach eliminates the need for complex material management while maintaining acceptable magnetic flux leakage levels through the simplified magnet embedding hole configuration that communicates with the rotor outer periphery.
Solution Approach 2:
The patent removes the side bridge structure that connected adjacent magnet embedding holes in conventional designs. By extracting this magnetic flux path, the patent reduces magnetic flux leakage without requiring alternating steel plate types, thereby simplifying the overall device structure.
2Object-generated harmful factors
If multiple types of rotor steel materials with different shapes are used, then magnetic flux leakage is reduced, but manufacturing precision and ease of manufacture deteriorate
Solution Approach 1:
The patent employs uniform rotor steel plates of a single type for the entire rotor assembly. This homogeneity allows all plates to be manufactured using the same punching die and process parameters, significantly improving manufacturing precision and ease of manufacture compared to alternating between different plate types.
Solution Approach 2:
The single type of rotor steel plate serves multiple functions: it provides structural support, contains the magnet embedding holes, and manages magnetic flux paths. This universal design eliminates the need for specialized different-shaped plates, simplifying the manufacturing process.
3Strength
If side bridges are added to connect inner and outer peripheral regions, then structural strength is improved, but magnetic flux leakage increases
Solution Approach 1:
The patent extracts or removes the side bridge structure from the rotor design. By eliminating this continuous magnetic flux path between adjacent magnet embedding holes, the patent reduces magnetic flux leakage while maintaining structural integrity through alternative design features.
Solution Approach 2:
The patent converts the potential harm of magnetic flux leakage by strategically positioning magnet embedding holes to communicate with the rotor outer periphery. This configuration allows magnetic flux to be controlled and directed beneficially while the absence of side bridges prevents unwanted flux paths.
4Device complexity
If magnet embedding holes are isolated from rotor outer periphery, then manufacturing complexity is reduced, but magnetic flux leakage increases
Solution Approach 1:
The patent extracts the side bridge structure that would normally connect magnet embedding holes, thereby reducing magnetic flux leakage paths. The magnet embedding holes communicate directly with the rotor outer periphery without intermediate connections, simplifying manufacturing while controlling magnetic flux.
5Object-generated harmful factors
If rotor steel plates are stacked with different shapes, then magnetic flux leakage is reduced, but assembly residual stress increases
Solution Approach 1:
The patent uses identical rotor steel plates throughout the rotor assembly, ensuring uniform dimensions and geometry. This homogeneity allows for consistent assembly processes and uniform stress distribution, eliminating the assembly residual stress problems associated with stacking different-shaped plates.
Solution Approach 2:
By removing the side bridge structure and allowing magnet embedding holes to communicate with the rotor outer periphery, the patent creates a more uniform stress distribution pattern during assembly, reducing concentrated residual stresses.
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 enhances rotor strength, reduces manufacturing costs, increases torque, improves ventilation for cooling, and allows for higher rotation speeds by dispersing stress regions, while simplifying the manufacturing process and reducing magnetic flux leakage.
Implementation Method 1
a rotor whose magnet embedding holes housing the permanent magnets communicate with a rotor outer periphery
Implementation Method 2
two permanent magnets disposed in a V shape so as to expand toward the outer side of a rotor form one pole
Implementation Method 3
dispersing stress regions, while simplifying the manufacturing process
Data Source
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AI summary
To provide an embedded permanent magnet type rotating electric machine which is superior in the strength of a rotor, can be manufactured at low cost, and can obtain a large torque. An embedded permanent magnet type motor, which has one pole configured of two permanent magnets 34a and 34b and has a plurality of poles of permanent magnets embedded in a rotor, includes a rotor 3 whose magnet embedding holes 35a and 35b communicate with a rotor outer periphery. The rotor 3 has between adjacent poles a q-axis projection 37 projecting in a direction away from a rotor rotation center. The magnet embedding holes 35a and 35b are disposed so as to form an inverted V shape. An outer peripheral edge portion 33 on the outer side of the permanent magnets 34a and 34b has a curvature radius smaller than the distance from a rotation center axis 4a to a rotor outermost peripheral portion. The outer peripheral edge portion 33 is provided with permanent magnet positioning projections 38a and 38b which restrain a movement of the permanent magnets 34a and 34b toward between adjacent poles.