Experimental Research on the Vibration and Noise Behavior of Helical Gearing System

Going with interior noise reduction in a vehicle, gear noise that is of pure frequency has been becoming a great influence on the comfortable driving. For decreasing the gear noise, it is important to predict precisely the gear noise behavior at the design stage before manufacturing. Therefore, it is necessary to clarify the physical mechanism of each resonance noise peak by actual measurement in the wide condition range of rotation speed and transmitting torque. In this research, a new 85kw oil-cooled motoring apparatus (Max speed: 6000rpm/135Nm, Max torque 400Nm/2000rpm) is developed for measuring the 3-dimensional (transverse, axial, rotational, and tilting) vibration of rotating gear blank. Also, the 3-directional (X, Y, and Z) vibration of the bearing’s holder, and the radiated gear noise are measured at the same time. As the result, the relationship between exciting vibration of rotating gear blank and the responding vibration of the bearing’s holder is carried out. The different effect upon the radiated gear noise of various vibration resonance modes is also investigated. Especially, some new interesting vibration modes, such as the drive and driven gears vibrate individually or synchronously, are found. Lastly, the mechanism of several resonance peaks which frequently causing the gear noise problems from slow city driving to fast highway operation, is conjectured concisely.