Rotary Compressor Torque Control via Dual Piston Volume Ratio
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Solution Overview
Problem
Conventional rotary compressors experience vibration due to variations in load torque during rotation, leading to potential damage and inefficiency.
Innovation Solution
A rotary compressor with a torque control mechanism that adjusts the output torque of the electric motor in response to load torque variations, maintaining a constant rotation speed and reducing vibration by setting the volume ratio of inner to outer cylinder chambers between 0.6 and 0.8.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the electric motor drives the piston to compress refrigerant in a conventional rotary compressor, then the compression function is achieved, but the load torque varies in one turn of rotation causing vibration
Solution Approach 1:
The patent applies periodic action by using two piston groups that operate in alternating cycles. Each piston group compresses refrigerant in half of the rotation cycle, while the other piston group compresses in the remaining half. This periodic alternation smooths the overall torque output, reducing vibration caused by single-cyclic torque variations while maintaining effective compression power.
2Object-affected harmful factors
If the load torque variation is reduced by design modifications, then vibration is suppressed, but the device complexity increases
Solution Approach 1:
The patent merges two compression cycles into a single integrated system where two piston groups share a common crankshaft and operate simultaneously. By combining the torque outputs of both piston groups through their synchronized operation, the system achieves vibration reduction without requiring separate drive mechanisms, thereby limiting the increase in device complexity.
Solution Approach 2:
The patent segments the compression function into two independent piston groups, each handling half of the compression cycle. This segmentation allows each piston group to operate with reduced individual torque variation, and when combined, they produce a smoother overall torque profile, effectively reducing vibration while maintaining a relatively simple unified structure.
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 solution effectively reduces vibration and maintains operational efficiency by minimizing load torque variations, enhancing energy savings and motor performance.
Implementation Method 1
an annular piston which is placed in the cylinder chamber to partition the cylinder chamber into an outer cylinder chamber and an inner cylinder chamber, and is configured to eccentrically rotate about the cylinder center
Implementation Method 2
The outer blade is inserted in the outer cylinder, is radially biased toward the inside of the annular piston, and has its tip in pressure contact with the outer peripheral surface of the annular piston
Implementation Method 3
a compressor which compresses refrigerant by utilizing a variation in the volume of a cylinder chamber caused by eccentric rotation of an annular piston
Data Source
Figure 1
Figure 2
Figure 3(A)~3(D)
AI summary
An annular cylinder chamber (C1, C2) of a cylinder (21) is partitioned into an outer cylinder chamber (C1) and an inner cylinder chamber (C2) with an annular piston (22). The cylinder (21) is caused to eccentrically rotate by driving an electric motor (30), thereby changing the volumes of the outer cylinder chamber (C1) and the inner cylinder chamber (C2). The volume ratio Vr of the inner cylinder chamber (C2) to the outer cylinder chamber (C1) is set at about 0.7. In this state, the output torque of the electric motor (30) is changed in accordance with a variation in the load torque in one turn of rotation.