Study Of Differential Magnet-moving Type Magnetoelectric Velocity Sensor For Automatic Balancing Machine

Balancing is the key problem must be solved during small and medium rotors'producing and manufacturing process. With the development of automatic balancing technology, automatic balancing machine is the necessary equipment to produce high quality rotors. Magnetoelectric velocity sensor which is the key part in automatic balancing machine is used to measure rotors' vibration. Automatic balancing machine is the device that will work in a long period, so the sensor's stability and reliability are required.Because of traditional coil-moving type magnetoelectric velocity sensor's inherent defect, the lines in the sensor are easily broken, causing device failure. Aiming at the disadvantages of the coil-moving type velocity sensor, a kind of enhanced differential magnet-moving type velocity sensor is studied. The thesis's main points are as follows:The structure design of differential magnet-moving type velocity sensorThe sensor's structure is designed; the advantages of the new sensor are discussed. Spring and permanent magnet are introduced; the spring's structure and the permanent magnet's material and properties are described.Analysis using Finite Element Method(FEM) softwareBecause analytical solution is hard to calculate, FEM software ANSYS is used to analyze the sensor. After introducing ANSYS,2-D spring model and 2-D permanent magnet model are built, the results of spring's stiffness and coil magnet flux are given.Result of sensor structure parameters'changesDifferent output characteristics results with sensor structure parameters'changes are studied. Methods for optimize sensor's structure are presented.Experimental verificationThe experiment compared with the standard velocity sensor is performed, as well as the unbalance test in a real machine.The results prove that the new type sensor has good output characteristics, can help to enhance automatic balancing machine's quality.