Research On Measuring & Data Processing Of Balancing Machine For Motorcycle Engine Crank-set

Unbalance means the non-uniform distribution of the mass of a rotor about its axis of rotation. Redistributing the mass (weight) more uniformly is necessary to restore balance. No rotor, or shaft can be manufactured with perfectly uniform weight distribution. Hence, all such components will display some degree of unbalance. Unbalance damages machinery by imposing cyclic forces on bearings and shafts that lead to fatigue failure. The purpose of "balancing"-of restoring uniformity of mass distribution insofar as possible-is not to eliminate all rotating system unbalance, but to bring it down to a tolerable level. To restore balance, that same number of gram-centimeters must be added to the assembly 180 degrees away. The balancing process, then, involves determining the number of gram-centimeters to be compensated for, and locating the proper angular position at which to add such compensation.As a rigid rotor with special configuration, the crank is always integrated with its accessory components such as shaft and piston when it is under working conditions. So, with the reciprocal mass of this combinational equipment, the dynamic unbalance of the crank has the special status in the field of the unbalance theory. This dissertation has presented a new method on the measuring and checking procedures of the dynamic unbalance of the motorcycle crank and made a deep research on its measuring device. What have been done is as follows:Firstly, the dissertation has thoroughly discussed the basic theory of rotor unbalance such as its varieties ,characters and rules of the movement which is under the excitation of the inertial force and inertial moment induced by the unbalance mass. It also has deeply expounded the dynamic mechanics of the specially formed components —crank, especially in the area of the crank integrated with shaft and piston. Secondly, based on the defects of the uptodate balancing machine which were employed in the motorcycle manufacture plants, this dissertation has presented a new method on the means of checking unbalance mass of the motorcycle engine crank set. It has adopted the hard-bearing balancing machine as the prototype,utilized tow group of resistance sensors placed in vertical direction with one another to pick up the information which stand for the inertial force of the motor engine crank set when it is running. Furthermore, on the theoretics of the balancing machine and associations with the practicalities of the motorcycle crank, it has reasoned out the test principles andmathematic model of the unbalance mass checking device of the motorcycle engine crank set, which is supported by the new method.Thirdly , a conclusion has been settled down in this dissertation: Because the shaft inertial force vector do not pass the center of the rotating center of the system, there is a moment generated by the shaft inertial force and the counterforce of the cylinder wall to counterbalance the pressure which is imposed by the piston, so, it is important to consider the tortile effect on the flexible supporting component of the balancing machine dedicated to motorcycle crank set, which is originated by the moment. Finally, this dissertation has made an exhaustive research on the data sampling and data processing. Based on the powerful APPWIZARD of the Microsoft Visual C++ 6.0 and the IPC5432 controls used as the application interface between the computer and the multifunctional data sampling board, this dissertation has developed the unbalance mass checking software which is applied into this balancing prototype machine.