Design And Implemention Of Automatic Balancing Machine For Small-sized Motor Rotors

Small-sized rotor is an indispensable rotary component for all kinds of motors。Constrained by manufacturing technology level, the quality distribution of the rotor is not always ideal symmetrical, causing an unbalance when rotating. An unbalanced and centrifugal force of rotor would lead to mechanical vibration, accelerating wearing and tearing of the bearing and causing noise pollution, which as a result may reduce the running performance of a motor. In engineering practice, rotor dynamic balancing is one effective method of correcting unbalance. Currently, the production of small and medium-sized motors accounts for 90% of domestic total output, leaving a promising market for rotor dynamic balancing. Nowadays, a majority of small and medium enterprises find themselves stuck in a situation where dynamic balancing and correction are processed separately. Considering this, a four-channel automatic balancing machine is designed with integration of testing and correction function, to improve the accuracy and efficiency of the motor rotor dynamic balancing, and create more economic benefits. Hence, this article is of great practical significance.Analyze the mechanical nature of rotor unbalance with reference to contemporary balancing theory of rigid rotor and the application of balancing technology, and then design a dynamic balancing plan accordingly based on influence-coefficient method. Select a correction strategy that dispensing rotor to add weight, according to the characteristics of small rotor; The accurate extraction of vibration signals determines the precision of calculating unbalance value, using FFT spectrum analysis as the extraction method of vibration signal amplitude and phase.Automatic balancing machine is divided into dynamic balancing measurement system and the main control system on PC. Balancing measuring system consists of four measuring boards with STM32 processor, collecting vibration signal,calculating amount of correction, driving dispensing correction; PC master coordinates measuring procedure with manipulator, achieving full automation of manufacturing processes. This article describes a detailed design and implementation of dynamic balancing measuring system and software and hardware of PC master control system.Finally, test communication stability of MODBUS protocol in prototype balancing machine by means of an overall operation trial, and compare the results from before and after correction to test the correction accuracy. The results indicate that automatic balancing system completes the whole process stably and smoothly and that the machine efficiency meets the expected goal.