Rotary Compressor Middle Plate Sizing for Shaft Deflection Control
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Solution Overview
Problem
Rotary compressors face challenges in reducing the diameter of the drive shaft to enhance compression efficiency while maintaining reliability, as a thin middle plate can deflect and deform under fluid pressure, leading to reduced reliability.
Innovation Solution
The rotary compressor design includes a compression mechanism with a middle plate thickness between 1/30 and 1/10 of the cylinder chamber diameter, eccentric pistons with a ratio of eccentric distance to radius of 0.25 or less, and specific suction pipe configurations to reduce deflection and enhance reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the middle plate is made thinner to reduce the distance between heads and improve drive shaft reliability, then the drive shaft deflection is reduced, but the middle plate strength is reduced causing it to deflect and deform under fluid pressure
Solution Approach 1:
The patent applies parameter changes by optimizing the thickness-to-diameter ratio of the middle plate to a specific range (1/30 to 1/10). This quantitative parameter adjustment allows the middle plate to be thin enough to reduce drive shaft deflection while maintaining sufficient strength to resist fluid pressure, thereby resolving the contradiction between drive shaft reliability and middle plate strength.
2Productivity
If the drive shaft diameter is reduced to increase compression efficiency, then the compression efficiency is improved, but the drive shaft becomes more prone to deflection reducing reliability
Solution Approach 1:
The patent resolves this contradiction by changing the parameter of drive shaft diameter to an optimal range that balances compression efficiency and reliability. The reduced diameter improves compression efficiency by decreasing friction losses, while the specific dimensional parameters ensure the drive shaft maintains sufficient rigidity to prevent excessive deflection during operation.
3Length of moving object
If the middle plate thickness is reduced to shorten the distance between heads, then the drive shaft deflection is reduced, but the middle plate may come into contact with rollers or other components
Solution Approach 1:
The patent applies parameter changes by defining a specific thickness range for the middle plate (1/30 to 1/10 of the cylinder chamber diameter). This optimized parameter ensures the middle plate is thin enough to reduce overall compressor height and drive shaft deflection, while maintaining adequate thickness to preserve necessary clearance between the middle plate and rotating components like rollers, preventing contact and ensuring reliable operation.
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 improves the reliability and efficiency of the rotary compressor by minimizing deflection and friction losses, allowing for higher rotational speeds and improved energy efficiency.
Implementation Method 1
a first piston (50) configured to rotate eccentrically along with rotation of the drive shaft (25) and thereby compress a fluid sucked into the first cylinder chamber (37)
Data Source
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AI summary
In a rotary compressor (10), a first cylinder chamber (37) defined by a front head (31) and a middle plate (38) is formed inside a first cylinder (35), and a second cylinder chamber (42) defined by the middle plate and a rear head (43) is formed inside a second cylinder (40). A first piston (50) and a second piston (60) are housed in the first cylinder chamber and the second cylinder chamber, respectively. The diameters Ds of both the first cylinder chamber and the second cylinder chamber and the thickness Tm of the middle plate satisfy a relational expression expressed as 1/30 ≤ Tm/Ds ≤ 1/10.