Rotary compressor, Rotor-Journal Bearing System, Three-dimensional Solid Element, Finite Element Method, Modal Analysis
In the rotary compressor, the rolling piston and the contacted rotor-journal bearing system are basically moving components. Because of the inertia forces and the periodically changing gas force acting on the rolling piston and the rotor, the journal bearing suffers very large loads. It always leads to serious vibration of the rotor-journal bearing system, and the wear of the rotor. Thus, the vibration must be reduced. In this paper, research works of vibration characteristics of the rotor-journal bearing system were carried out to provide evident of optimizing its structure to reduce the vibration. The average values of the natural frequencies and the vibration mode of the rotor-journal bearing system was obtained based on three-dimensional numerical simulations with finite element method using APDL routine. The power spectral density map of the exciting forces on rolling piston was obtained by the Fourier transformation. It could be used to judge whether resonance vibration would happen during working process of the compressor. The analysis results showed that the lateral vibration mode and the torsion vibration mode were the main vibration modes of the rotor-journal bearing system, and the first four orders of the exciting frequencies played a major role on the vibration of the system.