Hermetic Compressor Stator Spot Joining for Vibration Control
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Solution Overview
Problem
Hermetic compressors with concentrated winding motors experience increased vibration and noise due to magnetic flux concentration, leading to unbalanced radial forces and stress on the motor stator, which is exacerbated by high internal pressures in CO2 refrigerant systems, making traditional fixing methods like shrink or press fitting ineffective.
Innovation Solution
A hermetic compressor design featuring an annular motor stator with spot joining portions that secure the motor stator to a cylindrical casing with a controlled clearance, preventing vibration and noise transmission by limiting the joining area to less than 10% of the perimeter and using spot welding to maintain stability under high pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the motor stator is fixed to the casing by shrink fitting or press fitting, then the motor stator is securely fixed, but stress acts on the yoke of the motor and iron loss increases
Solution Approach 1:
The fixing method is segmented from continuous contact (shrink/press fitting) to discrete spot joining portions. The motor stator is fixed at specific localized spots rather than along the entire circumferential surface, reducing stress distribution while maintaining fixing stability.
Solution Approach 2:
The fixing structure transitions from uniform continuous fixing to non-uniform local fixing. Spot joining portions are strategically positioned at specific locations where fixing is most effective, allowing other areas to remain clear and stress-free, thereby reducing overall iron loss in the yoke.
2Stability of the object's composition
If the motor stator is fixed by shrink fitting or press fitting, then the motor stator is secured, but in CO2 refrigerant systems with high internal pressure, it is difficult to fix the motor stator inside the casing
Solution Approach 1:
The fixing approach is divided into discrete spot joining portions rather than requiring continuous circumferential fixing. This segmentation allows the motor stator to be fixed effectively even under high internal pressure from CO2 refrigerant, as the spot joining method is less sensitive to pressure-induced expansion compared to shrink or press fitting.
Solution Approach 2:
The fixing method changes from pressure-dependent continuous fixing (shrink/press fitting) to localized spot joining. This parameter change in the fixing mechanism makes it suitable for high-pressure CO2 systems where the casing expansion would prevent effective continuous fixing.
3Stability of the object's composition
If the motor stator is fixed with continuous contact to the casing, then the motor stator is securely mounted, but vibration and noise of the casing increase
Solution Approach 1:
The mounting structure is segmented into discrete spot joining portions rather than continuous contact. This segmentation creates clearances between the motor stator and casing at non-fixing areas, preventing vibration transmission paths while maintaining secure mounting at the spot joining locations.
Solution Approach 2:
The harmful continuous contact between motor stator and casing is extracted/removed, replacing it with discrete spot joining portions. This extraction eliminates the vibration transmission pathway while preserving the essential mounting function through the spot joining portions.
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 compressor casing vibration and noise, reduces iron loss, and simplifies the manufacturing process by allowing secure motor stator fixation without the need for conventional fixing methods, while maintaining operational stability and reducing manufacturing costs.
Implementation Method 1
The plural spot joining portions fix the motor stator to the cylindrical portion by spot joining in a state where a clearance is secured between the motor stator and the cylindrical portion
Data Source
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AI summary
To provide a hermetic compressor that can suppress vibration of a casing. A hermetic compressor (1) is disposed with an annular motor stator (8), a motor rotor (9), a casing (2) and plural spot joining portions (7). The motor rotor (9) is disposed such that it may freely rotate in a space inside the motor stator (8). The casing (2) includes a cylindrical portion (10). The cylindrical portion (10) houses the motor stator (8) and the motor rotor (9). The plural spot joining portions (7) fix the motor stator (8) to the cylindrical portion (10) by spot joining in a state where a clearance is secured between the motor stator (8) and the cylindrical portion (10).