Rotor, motor, compressor, and air conditioner
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Solution Overview
Problem
The integration of a bridge in the magnet insertion hole of a permanent magnet-embedded rotor leads to demagnetization due to the concentration of magnetic flux, especially when combined with slits, which enhances the likelihood of demagnetization of the permanent magnet.
Innovation Solution
The rotor design includes a rotor core with slits on the outer side of the magnet insertion hole in a radial direction and a bridge connecting the inner and outer sides, where the shortest distance from the magnet insertion hole to the first slit is shorter than the distance from the reference point to the second slit closest to the bridge, thereby reducing the harmonic component of the induced voltage and suppressing magnetic flux concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a bridge is provided in the magnet insertion hole to enhance rotor core strength, then the rotor core strength is improved, but magnetic flux concentration occurs around the bridge causing demagnetization of the permanent magnet
Solution Approach 1:
The patent applies local quality by creating an asymmetric slit configuration where the first slit is positioned at a specific distance from the magnet insertion hole while the second slit is positioned at a different distance. This local structural variation modifies the magnetic flux distribution specifically in the critical region around the bridge, reducing flux concentration and preventing demagnetization without compromising the overall rotor core strength enhancement provided by the bridge structure.
2Object-generated harmful factors
If slits are formed on the outer side of the magnet insertion hole to reduce harmonic component of induced voltage, then the harmonic component is reduced, but magnetic flux concentration occurs between the magnet insertion hole and slits flowing into the permanent magnet through the bridge
Solution Approach 1:
The patent employs asymmetry by configuring the slits at different distances from the magnet insertion hole - the first slit at distance T1 and the second slit at distance R1 where R1 > T1. This asymmetric arrangement creates an optimized magnetic flux path that effectively reduces the harmonic component of induced voltage while simultaneously preventing flux concentration that would lead to demagnetization through the bridge structure.
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 harmonic component of the induced voltage and inhibits demagnetization of the permanent magnet, enhancing the rotor's strength and reliability by distributing magnetic flux more evenly.
Implementation Method 1
When the rotor rotates, a magnetic field of the permanent magnet induces a voltage in coils of a stator
Implementation Method 2
a magnetic field of the permanent magnet induces a voltage in coils of a stator
Implementation Method 3
magnetic flux generated by a magnetic field (demagnetizing field) from a stator may flow into the bridge
Data Source
AI summary
A rotor includes a rotor core having an outer circumference extending in a circumferential direction about an axis, and having a magnet insertion hole along the outer circumference, and a permanent magnet disposed in the magnet insertion hole. The rotor core has a plurality of slits formed on an outer side of the magnet insertion hole in a radial direction about the axis, and a bridge extending to connect an inner side and an outer side of the magnet insertion hole in the radial direction. The plurality of slits have a first slit closest to an end of the magnet insertion hole in the circumferential direction, and a second slit closest to the bridge. When T1 represents a shortest distance from the magnet insertion hole to the first slit and R1 represents a shortest distance from the reference point to the second slit, R1>T1 is satisfied.