DYNAMIC BALANCING OF ROTORS USED IN INSTRUMENT MAKING,

Dynamic balancing consists of determining the magnitude and location of the imbalance and then eliminating or controlling it while a rotor is rotating. These two problems are solved separately at different stages. The first problem is solved by changing the rotary motion of the rotor into angular oscillatory motion about its axis where the maximum angular deviation is on the order of a few degrees. The angular location of the imbalance as well as its magnitude are determined by the same transducers. The schematic diagram of the proposed method is shown. The method can be briefly described as follows The imbalanced rotor rests on two supports I and II suspended on springs of given stiffness h sub 1 and h sub 2 directed along two coordinate axes. The rotor is set into oscillatory motion by one of three methods discussed in the paper. The problem now is to determine the amounts of metal which must be added or removed from the surface of the rotor, and their location, in order to balance it. The mechanical oscillations of the supports, caused by the imbalance, are measured by means of transducers e.g., piezoelectric transducers the angular displacements of the investigated rotor alpha sub 1 and alpha sub 2 are measured by means of ratiometers. The sensitivity of the method is determined on an example of a symmetrical rotor whose imbalance is due only to the displacement of its mass center from the axis of rotation, r. The paper shows two schematic diagrams of two versions of the method for the determination of a dynamic imbalance.