Design And Research Of Motorcycle Engine Crank-connecting Rod Mechanism Balancing Machine

Unbalance means the non-uniform distribution of the mass of a rotor about its axis of rotation. The process of redistributing the mass (weight) more uniformly is balancing. No rotor 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-connecting Rod Mechanism is always integrated with its accessory components such as crank shaft , connecting rod and piston when it is under working conditions. So, with the reciprocal mass of this combinational equipment, the dynamic unbalance of the Crank-connecting Rod Mechanism 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 single-cylinder engine Crank-connecting Rod Mechanism 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, damages, 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 shaft, especially in the area of the Crank-connecting Rod Mechanism.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 single-cylinder engine Crank-connecting Rod Mechanism. 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 ofthe 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 and mathematic model of the unbalance mass checking device of the motorcycle engine crank set, which is supported by the new method. The model machine has been designed out Now, it is being made.Thirdly, a conclusion has been settled down in this dissertation: The rate of dynamic balance of the motorcycle single-cylinder engine Crank-connecting Rod Mechanism equal to the quotient of rotating unbalance gram-centimeters divided by reciprocal mass unbalance gram-centimeters. That means:When When Fourthly, this dissertation has made an exhaustive research on the data measurement ascertaining and an simple analysis on the data sampling and data processing. Furthermore, the request and conformation of the unbalance mass checking software, which is applied into this balancing prototype machine, has been brought forward in thisdissertation.Finally, according to the balancing process of the motorcycle engine crank set-JL100 model made by JIALING industry, this dissertation has put forward methods which modified the dynamic balance of the Crank-connecting Rod Mechanism.