Auxiliary Shaft Diameter Increase in Two-Cylinder Hermetic Compressor
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Solution Overview
Problem
In two-cylinder hermetic compressors, the stress exerted from compression chambers is dispersed, resulting in significant stress on the auxiliary shaft portion, leading to increased sliding frictional wear, which is not effectively addressed by existing designs.
Innovation Solution
The diameter of the auxiliary shaft portion is set larger than that of the main shaft portion, and the thrust load is received by the surface of an auxiliary bearing on the second cylinder, allowing for a larger receiving area and reduced sliding loss on the first eccentric portion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the diameter of the auxiliary shaft portion is set smaller than the diameter of the main shaft portion, then the device complexity is reduced, but the auxiliary shaft portion experiences large stress and increased sliding frictional wear in two-cylinder compressors
Solution Approach 1:
The shaft is designed with different diameters at different locations: the auxiliary shaft portion has a larger diameter than the main shaft portion to handle high stress and wear, while the main shaft portion maintains a smaller diameter. This local differentiation optimizes both reliability and complexity.
Solution Approach 2:
Instead of making the auxiliary shaft portion smaller as in conventional designs, the invention inverts the approach by making it larger to specifically address the high stress and wear problems in two-cylinder compressors.
2Device complexity
If the thrust load is received by the auxiliary shaft portion, then the structure is simpler, but the auxiliary shaft portion experiences high stress and increased wear
Solution Approach 1:
The thrust load reception function is extracted from the auxiliary shaft portion and transferred to the auxiliary bearing. This allows the auxiliary bearing to handle the thrust load while the auxiliary shaft portion can be optimized for its rotational support function with appropriate diameter.
Solution Approach 2:
The auxiliary bearing acts as an intermediary element between the shaft and the thrust load. It mediates the thrust load reception, protecting the shaft from direct thrust load exposure and reducing wear on the shaft surface.
3Strength
If the diameter of the first eccentric portion is set larger, then the sliding loss increases, but the structural strength is improved
Solution Approach 1:
The invention optimizes the diameter parameter of the first eccentric portion by setting it smaller than the second eccentric portion. This parameter change reduces the sliding loss while maintaining sufficient structural strength through proper design of the eccentric mechanism.
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 configuration reduces maximum stress on the auxiliary shaft portion, suppresses sliding frictional wear, and stabilizes the thrust load reception, demonstrating a significant reduction in stress values and wear rates.
Implementation Method 1
a thrust load of the shaft is received by the surface of an auxiliary bearing on the side of a second cylinder. According to the configuration in which the thrust load is received by the surface of the auxiliary bearing on the side of the second cylinder, an area of a receiving portion is easy to be designed to be large as compared to the configuration of receiving the thrust load on the auxiliary shaft portion, whereby the thrust load can be stably received.
Implementation Method 2
a diameter of the auxiliary shaft portion is set larger than a diameter of a main shaft portion. According to this configuration, maximum stress exerted on the auxiliary shaft portion is reduced, whereby an amount of sliding frictional wear on the auxiliary shaft portion can be suppressed.
Implementation Method 3
stress exerted from each of compression chambers is dispersed into the main shaft portion and the auxiliary shaft portion, so that large stress is also applied on the auxiliary shaft portion.
Data Source
AI summary
In the two-cylinder hermetic compressor, a first compression mechanism unit includes a first cylinder and a first piston, and a second compression mechanism unit includes a second cylinder and a second piston. A main bearing is disposed on one surface of the first cylinder, and an intermediate plate is disposed on another surface of the first cylinder. The intermediate plate is disposed on one surface of the second cylinder, and an auxiliary bearing is disposed on another surface of the second cylinder. A shaft is constituted by a main shaft portion which has a rotor attached thereto and is supported by the main bearing, a first eccentric portion having a first piston attached thereto, a second eccentric portion having a second piston attached thereto, and an auxiliary shaft portion supported by the auxiliary bearing. The diameter of the auxiliary shaft portion is set larger than the diameter of the main shaft portion.