Outer rotor and compressor having the same
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Solution Overview
Problem
Existing reciprocating compressors with inner rotor motors have limited moment of inertia due to the size constraints of the stator, which can lead to noise and vibration issues.
Innovation Solution
The use of an outer rotor motor in a compressor, featuring a core with permanent magnets, a roof with notches to absorb deformation, and a bush for rotational support, helps to increase the moment of inertia and prevent cracks that could cause noise and vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If an inner rotor motor is used in a compressor, then the device complexity is reduced, but the moment of inertia of the rotor is limited by the size of the stator
Solution Approach 1:
The patent inverts the traditional inner rotor configuration to an outer rotor configuration. Instead of placing the rotor inside the stator, the rotor is positioned outside the stator, allowing the rotor to have a larger moment of inertia while maintaining a compact overall structure. This inversion resolves the contradiction by enabling higher moment of inertia without increasing device complexity.
2Stability of the object's composition
If the rotor size is increased to improve moment of inertia, then the moment of inertia increases, but the stator size must also increase which increases device complexity
Solution Approach 1:
By inverting the motor configuration to outer rotor type, the patent allows the rotor to be enlarged for higher moment of inertia while the stator remains compact. The stator serves only as a magnetic field generator and does not need to increase in size proportionally with the rotor, thus resolving the contradiction between moment of inertia and device complexity.
3Ease of manufacture
If a resin roof is used to cover the core, then manufacturing ease is improved, but thermal expansion differences can cause cracks
Solution Approach 1:
The patent applies local quality by creating notches at specific locations on the resin roof where thermal stress concentrates. These notches are strategically positioned to absorb expansion forces and prevent crack propagation, allowing the resin roof to maintain its manufacturing advantages while improving reliability through localized structural modifications.
Solution Approach 2:
The notches in the resin roof serve as beforehand cushioning elements that absorb thermal expansion stress before it can cause cracks. By pre-introducing these controlled discontinuities, the patent prevents unexpected crack formation during thermal cycling, thereby improving reliability while maintaining the ease of resin manufacturing.
4Reliability
If notches are added to the roof to prevent cracks, then reliability is improved, but the roof structure becomes more complex
Solution Approach 1:
The notches are applied locally at critical stress concentration points on the resin roof rather than throughout the entire structure. This localized approach improves crack resistance while minimizing the increase in overall structural complexity, as the notches are simple geometric features integrated into the existing roof design.
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 outer rotor design enhances the compressor's performance by preventing cracks and maintaining balance, thereby reducing noise and vibration, and ensuring efficient operation.
Implementation Method 1
a resin outer rotor including a core formed in a hollow cylindrical shape, a plurality of permanent magnets disposed on an inner circumferential surface of the core, a roof disposed to cover one end of the core... the core and the bush is made of a metal material, and the roof is made of a resin material
Implementation Method 2
a plurality of permanent magnets disposed on an inner circumferential surface of the core
Implementation Method 3
The outer rotor motor may include a stator and an outer rotor disposed outside the stator
Implementation Method 4
because the inner rotor motor has a rotor disposed inside a stator, the moment of inertia of the rotor may be limited by the size of the stator. To increase the moment of inertia of the rotor, an outer rotor motor may be used
Data Source
AI summary
An outer rotor for a compressor is provided. The outer rotor includes a core formed in a hollow cylindrical shape, a plurality of permanent magnets disposed on an inner circumferential surface of the core, a roof disposed to cover one end of the core and including a bush hole formed at a center of the roof, and a bush disposed in the bush hole of the roof, wherein the core and the bush are made of a metal material, and the roof is made of a resin material, and wherein the roof includes at least one inner notch formed on an inner circumferential surface of the bush hole and at least one outer notch formed on an outer circumferential surface of the roof.