Electric motor and compressor having the same
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Solution Overview
Problem
Existing electric motors with permanent magnets suffer from increased vibration and noise due to Magnetic Pull Force (MPF), decreased inertia, and reduced operation efficiency at low speed rotation, primarily because of symmetric slits formed around the d-axis, which limit magnetic flux distribution and increase pressure.
Innovation Solution
The electric motor design features an asymmetrical slot configuration where the core area of the front portion of the d-axis is smaller than the rear portion, with specific slot arrangements and flux barriers to manage MPF and enhance magnetic flux distribution, thereby reducing vibration and noise and improving inertia and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If symmetric slits are formed around the d-axis in the rotor core, then magnetic flux distribution is improved, but vibration and noise increase due to decreased rotor inertia
Solution Approach 1:
The patent applies asymmetry by forming slits only in the front portion of the d-axis (between 0 to 90 degrees) while leaving the rear portion (between 90 to 180 degrees) without slits. This asymmetric configuration maintains improved magnetic flux distribution in the critical front region while preserving rotor inertia by avoiding material removal in the rear region, thereby reducing vibration and noise during unidirectional rotation.
Solution Approach 2:
The patent applies local quality by selectively forming slits only in specific regions (front portion of d-axis) where they are most needed for magnetic flux management, while maintaining solid rotor structure in other regions (rear portion of d-axis) to preserve inertia. This localized approach optimizes the balance between magnetic performance and mechanical stability.
2Manufacturing precision
If slits are formed in both sides with respect to the d-axis, then magnetic flux distribution is enhanced, but operation efficiency decreases due to increased pressure during low speed rotation
Solution Approach 1:
The patent forms slits asymmetrically, placing them only in the front portion of the d-axis (0 to 90 degrees) and omitting them from the rear portion (90 to 180 degrees). This asymmetric design enhances magnetic flux distribution where needed while minimizing the total volume of material removed, thereby maintaining rotor inertia and reducing pressure buildup during low-speed rotation to preserve operation efficiency.
3Object-affected harmful factors
If symmetric slits are formed to reduce Magnetic Pull Force vibration, then vibration and noise are reduced, but rotor inertia decreases
Solution Approach 1:
The patent applies asymmetry by confining slits to the front portion of the d-axis (0 to 90 degrees) while leaving the rear portion (90 to 180 degrees) intact. This selective placement reduces Magnetic Pull Force vibration in the critical front region where slits are most effective, while preserving rotor inertia by maintaining solid structure in the rear region that contributes significantly to rotational mass.
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 design effectively suppresses vibration and noise, maintains rotor inertia, and enhances operation efficiency during low-speed rotation by asymmetrically managing Magnetic Pull Force and magnetic flux distribution.
Implementation Method 1
an electric motor is an apparatus that converts electric energy into mechanical energy... the AC motor is widely used because of its simple structure, small size, and light weight
Implementation Method 2
vibration and noise are problematically increased due to a Magnetic Pull Force (MPF) acting between the stator and a core disposed outside the permanent magnets of the rotor core
Data Source
AI summary
The present disclosure relates to an electric motor, and a compressor having the same. The electric motor includes a stator, and a rotor. The rotor includes a rotation shaft, a rotor core, and a plurality of permanent magnets. The rotor core includes permanent magnet insertion portions each formed therethrough in an axial direction so that the permanent magnet is inserted, and slots each formed through the rotor core in a manner that a core area of a front portion of a d-axis is smaller than a core area of a rear portion of the d-axis in a rotating direction of the rotor when an outer core part of the permanent magnet insertion portion is divided with respect to the d-axis. Accordingly, a decrease in inertia can be suppressed and an occurrence of vibration and noise due to Magnetic Pull Force (MPF) can be prevented.