Sealed Compressor Bearing Structure to Prevent Shaft Wear
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Solution Overview
Problem
Conventional sealed compressors experience wear due to solid contact between the bearing and main shaft when the stator is fixed, leading to reduced durability.
Innovation Solution
Incorporating a non-sliding portion between the main shaft and bearing, which is formed by narrowing the outer diameter of the main shaft, prevents solid contact and deformation-related wear by providing a buffer zone during stator fixation, enhancing durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the stator is fixed to the bearing by press-fitting, then the stator can be securely mounted, but the inner peripheral surface of the bearing is deformed and solid contact occurs between the bearing and main shaft causing wear
Solution Approach 1:
The sliding portion of the main shaft is segmented into multiple regions along the axial direction, with non-sliding portions positioned at both ends and a sliding portion in the middle. This segmentation allows the bearing's inner peripheral surface to deform during stator fixation without causing solid contact, as the non-sliding portions are located where deformation occurs, while the sliding portion remains in the non-deformed middle region.
Solution Approach 2:
Different regions of the main shaft are given different functional properties: the non-sliding portions at both ends are designed to be non-contact regions where bearing deformation occurs during stator fixation, while the central sliding portion maintains contact for proper lubrication and load bearing. This local differentiation of functional properties resolves the contradiction between secure stator mounting and bearing durability.
2Volume of moving object
If the sealed compressor is miniaturized using an outer-rotor-type motor, then the height and size are reduced, but the bearing becomes susceptible to deformation during stator fixation
Solution Approach 1:
The main shaft's sliding portion is divided into multiple axial regions with non-sliding portions at both ends and a sliding portion in the center. This segmentation strategy allows the bearing to deform during stator fixation without compromising the sliding interface, enabling miniaturization while maintaining structural integrity.
Solution Approach 2:
The non-sliding portions are pre-positioned at both ends of the main shaft before stator fixation. This preliminary arrangement ensures that when the stator is fixed by press-fitting and the bearing deforms, the deformation occurs at the non-sliding portions rather than at the sliding interface, thus preventing wear and maintaining structural integrity in the miniaturized compressor.
Data Source
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AI summary
In a sealed compressor, electrically-operated element (104) and compressive element (106) driven by electrically-operated element (104) are housed in the inside of sealed container (102). Compressive element (106) includes shaft (126) formed of main shaft (136) and eccentric shaft (134), and cylinder block (128) having: bearing (144) which pivotally supports main shaft (136) of shaft (126); and cylinder (142). Further, the compressive element (106) includes piston (130) which is movable in the cylinder (142) in a reciprocating manner, and connecting portion (132) which connects eccentric shaft (134) and piston (130) to each other. Electrically-operated element (104) is formed of an outer-rotor-type motor which includes stator (150), and rotor (152) which is disposed coaxially with stator (150) so as to surround an outer periphery of stator (150). Further, non-sliding portion (146) is provided between main shaft (136) and bearing (144), and stator (150) is fixed to outer peripheral portion (162) of bearing (144) which corresponds to non-sliding portion (146).