高血圧患者における自己管理行動と精神心理的要因および社会的要因との関係

早大学位記番号:新6843早稲田大

The Mechanism Discuss of Periodic Sound in Rolling Piston Compressor under Low Operating Frequency in Air-conditioner System

With the popularization of the inverter-driven air-conditioner and the requirement of comfort and energy saving, the operating frequency of inverter-driven air-conditioner is lower and lower, even to 1Hz. But when the air-conditioner operates under the frequency of 10Hz, a periodic sound will appear in the air-conditioner outdoor unit, which should be researched and solved. According to the experiment test and theoretical analysis, it is found that the periodic sound is the excited resonance when the valve opens. The resonator is composed by the discharge port of top-flange and discharge cavity which is made up by cylinder, roller, top-flange and bottom-flange. In one cycle the characteristic of the periodic sound is that the sound will be only taken place when the valve opens and the frequency of the sound will be higher and higher with the crank angle increasing. According to the experimental testing about different type compressor and air-conditioner outdoor unit, it is found that this sound exists in every kinds of rolling piston compressor. Using proper muffler and increasing the thickness of the valve could both reduce this periodic sound

Research On Low Frequency Vibration Of Rotary Compressor

The abnormal noise of an outdoor domestic air-conditioner operating at low speed is experimentally analyzed. The structure-borne noise which passes through the mounting system is confirmed to be the main source of the abnormal noise due to the large low frequency vibration on compressor foot. Then the characteristic of low frequency vibration of rotary compressor including the dynamic model, exciting forces and dynamic response is researched. Based on this, mounting system including compressor foot and rubber grommet is optimized to solve this problem, more than 8dB reduced