Eccentric Portion Offset in Two-Cylinder Hermetic Compressor
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Solution Overview
Problem
Two-cylinder hermetic compressors face increased maximum stress on eccentric portions due to reduced outer diameter and height, leading to increased sliding frictional wear and loss.
Innovation Solution
The center positions of the eccentric portions are offset from the piston centers, with the eccentric portion centers located closer to the bearings and the distance between them greater than between the piston centers, reducing maximum stress and sliding frictional wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the outer diameter and height of the eccentric portions are decreased to reduce sliding loss, then the sliding loss is reduced, but the maximum stress on the eccentric portions increases
Solution Approach 1:
The patent applies local quality by offsetting the center position of the eccentric portion from the center position of the piston, creating an asymmetric configuration. Specifically, the eccentric portion center is positioned closer to the bearing than the piston center, which distributes the stress more favorably during operation. This local positional adjustment reduces the maximum stress concentration on the eccentric portion while preserving the reduced dimensions that lower sliding loss.
2Loss of energy
If the height of the eccentric portions is decreased to reduce sliding loss, then the sliding loss is reduced, but the sliding area of the eccentric portions decreases
Solution Approach 1:
The patent changes the positional parameter of the eccentric portion relative to the piston, specifically offsetting the eccentric portion center from the piston center by a predetermined distance toward the bearing. This parameter change allows the eccentric portion to maintain a smaller height (reducing sliding loss) while the offset position compensates for the reduced sliding area by optimizing the load distribution and contact characteristics during operation.
Data Source
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AI summary
A main bearing is disposed on one surface of a first cylinder, an intermediate plate is disposed on another surface of the first cylinder, the intermediate plate is disposed on one surface of a second cylinder, and an auxiliary bearing is disposed on another surface of the second cylinder. A shaft is constituted by a main shaft portion, a first eccentric portion, a second eccentric portion, and an auxiliary shaft portion. A first eccentric portion center position (H1/2) which is the center position of the first eccentric portion in height (H1) is located at a position closer to the main bearing than a first piston center position (P1/2) which is the center position of a first piston in height (P1). A second eccentric portion center position (H2/2) which is the center position of the second eccentric portion in height (H2) is located at a position closer to the auxiliary bearing than a second piston center position (P2/2) which is the center position of a second piston in height (P2).