The built-in sensor bearing to measure shaft behavior of compressor for air-conditioning

공조용 압축기 축 거동 측정용 베어링 내장형 센서

We developed a built-in sensor bearing to measure the rotor motion of a rolling piston type compressor for the air conditioner. Because of needs for the high efficiency and long life span of compressor, and the usage of alternative refrigerants, the operating condition of the compressor becomes more severe. The accurate measurement of the rotor motion of the compressor can contribute greatly to the design and analysis of the hydrodynamic bearing. However, it is difficult to measure accurately the shaft behavior of small compressor because of the small space for the sensor mount, high temperature and pressure of compressor, oil mixed with refrigerant, and electromagnetic noise of the motor. To overcome these difficulties, we develop the cylindrical capacitive sensor that is built in the hydrodynamic bearing and calibrate the built-in sensor bearing indirectly through measuring the oil relative permittivity. We measured the rotor motion as well as suction and discharge pressures in various conditions. The several experimental results show that the developed built-in sensor bearing can measure the rotor motion not only in steady state but also in transient state.