Research On Measuring Dynamic Balancing Of Motorcycle Crank Module

Motorcycle crank module is a special rigid rotor. It consists of crankshaft and rod. It belongs to unbalanced rotor. Motorcycle has single clinker motor. It works in unbalanced situation. For its specific characteristic, it's very important to make research on measuring dynamic balancing of motorcycle crank module. A new type of equipment for measuring dynamic balancing of motorcycle crank module is proposed along with a description of its measuring principle and construction.The dynamics characteristics of motorcycle crank module are analysed firstly. The resource of vibration concludes revolving inertial force and reciprocal inertial force. An inertial force ellipse can descript the vectorial sum of the two inertial forces. The characteristic parameters of the inertial force ellipse are unbalance rate (η) and obliquity of the ellipse principal axis (φ). So these two parameters also can descript the dynamics characteristics of motorcycle crank module.When the unbalanced crank module rotates, its supporting system is vibrated by unbalanced centrifugal forces. Vibration sensors that are attached to the vibration table detect the vibration signal. By signal processing, amount of unbalance can be observed. So the design of vibration table is a key to the whole measuring system. A new type of vibration table is designed by analyzing soft bearing system and hard bearing system. The system has the features of high rigidity and high measuring precision.A calibration method for the measuring system is given. Four-step calibration method is created based on the concept of influence coefficient, which is used to calibrate the soft bearing-balancing machine.A virtual instrument is explored based on LabVIEW. It improves the flexibility and expansibility of the measuring system.At last in this paper, the measuring results are given. The result shows that this measuring system has the advantage of high precision, high efficiency and low cost.