1956 年 22 巻 115 号 p. 178-181
A rotating shaft which is driven through an universal joint such as the propeller shaft of an automobile sometimes shows bad vibrations at lower speeds than its ordinary critical speed. This report deals with the resonance phenomenon due to the angular velocity variation caused by the universal joint. This angular velocity variation occurs two times during one revolution of the shaft and theoretically gives an exciting force with the frequency three times as high as the rotating speed. Thus, when the shaft is driven at one third of the ordinary critical speed, the frequency of the exciting force caused by the angular velocity variation coincides with the ordinary critica1 speed and the natural frequency of the shaft, causing resonance vibration. This phenomenon is also confirmed by model tests.