Hermetic Compressor Rotor with Downward Extending Core
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Solution Overview
Problem
Prior art hermetically sealed compressors face challenges in maintaining stable operation of the crankshaft with increasing motor size and power, as increasing the main bearing height compromises lubrication performance and reducing the inner diameter portion height decreases clamping force, making secure operation difficult.
Innovation Solution
The rotor features a downwardly extending tapered portion with a press-fitted inner diameter portion for the crankshaft and an inner tubular portion for lubricant pickup, allowing for a longer main bearing without increasing overall height and eliminating the need for a separate lubricant pick-up tube, enhancing fixation and lubrication performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the height of the main bearing is increased to safeguard stable operation of the crankshaft, then the reliability is improved, but the overall height of the compressor must be increased which impedes lubrication performance and increases transportation costs
Solution Approach 1:
The rotor core extends downwardly beyond the stator core in the vertical dimension, allowing the main bearing to be positioned lower and achieve greater height without increasing the overall compressor height. This dimensional reconfiguration enables the bearing to maintain improved crankshaft stability while keeping the compressor footprint unchanged.
Solution Approach 2:
The rotor core is nested within the stator core assembly, with the rotor extending downwardly to provide bearing support. This nesting arrangement allows the bearing to be housed within the motor assembly space rather than requiring additional external space, thus improving reliability without increasing overall dimensions.
2Reliability
If the height of the inner diameter portion is reduced to accommodate longer main bearing, then the manufacturing cost is reduced, but the clamping force between the inner diameter portion and crankshaft decreases
Solution Approach 1:
The rotor core is divided into distinct portions: an outer diameter portion that interfaces with the stator and an inner diameter portion that interfaces with the crankshaft. This segmentation allows the outer diameter portion to provide structural support and the inner diameter portion to provide clamping force, enabling both functions to be optimized independently.
Solution Approach 2:
The inner diameter portion is designed with specific dimensional characteristics optimized for clamping the crankshaft, while the outer diameter portion is designed for stator integration. This local optimization ensures that each portion performs its specific function effectively, maintaining clamping force while accommodating the longer bearing requirement.
3Adaptability or versatility
If the overall height of the compressor is increased to accommodate larger electric motors with varying sizes, then the adaptability is improved, but the utilizable volume of the refrigeration appliance decreases
Solution Approach 1:
The motor assembly with the extended rotor core serves multiple functions: it houses the electric motor, provides crankshaft support through the extended bearing, and maintains a compact overall height. This multi-functional design allows the same basic compressor architecture to accommodate motors of varying sizes without requiring changes to the overall compressor dimensions, thereby preserving refrigeration appliance volume.
Data Source
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AI summary
The present invention relates to a rotor (1) for use in an electric motor (2) of a hermetically sealed compressor (3). The rotor (1) comprises a core (8) which has a through hole (9) for receiving the crankshaft (6) of the compressor (3). The motor (2) comprises a stator (10) which has a core (11) with a height H1. The rotor core (8) comprises an outer diameter portion (14) which has a height H1 and an inner diameter portion (15) which has a height H2 for receiving the crankshaft (6) by press-fitting.