Research Of Piezoelectric Film Force Sensor Of Ball Cold Heading Machine

In the field of mechanical transmission, the bearing is a kind of an integral part, and has agreat impact on its operating characteristics of the application host. As a rolling element in thebearing, balls are under pressure. A large number of experiments show that the processingquality and bearing performance are closely linked. Cold heading is a common method of theball forming. It make cylindrical blank to spherical balls by using cold heading machine.However, forming defects are produced in the cold heading process. If it is not promptlydiscovered and resolved, forming poor quality and a lot of defective will be produced. In orderto solve this problem, domestic scholars from cold heading process improvement andoptimization of cold heading machine structure of point of view, do a lot of theoretical andexperimental studies which greatly improves the quality of balls forming. But many researchesdo not solve the problem of forming defects from the source. Compared with foreign researchresults, the study of quality monitoring system is still relatively small, which resulted in a lowball cold heading equipment mechatronics and hindered the development of the steel ballmanufacturing. Therefore, this issue with piezoelectric film sensors used to monitor the ballforming quality as the research object. Four aspects will be analyzed that structural design,mathematical modeling, numerical simulation and experimental studies. A theoretical basisabout the development of forming quality monitoring system will be provided.This work is supported by a grant from the National Natural Science Foundation of China(Grant No.51205165) and Youth Star program of Jinan (Grant No.20120125). Conversionbetween mechanical energy and electric energy is achieved by piezoelectric film force sensorthat based on the piezoelectric effect mechanism. Ball forming process will be reflected by coldheading force. The extraction method of the bottom die load signal is chose. Cold heading forceis transformed into an electrical signal by piezoelectric force sensor. Ball cold heading processonline monitoring is realized by observing variation of the electrical signal.First, research status is introduced about PVDF piezoelectric film and piezoelectric forcesensors. The domestic cold heading about the method of improving the quality is pointed out.Inadequate research is indicated. An online monitoring method on ball forming quality isproposed by using load signal analysis. Second, a new upper and lower support structure of piezoelectric force sensor is designedby using PVDF piezoelectric film as force sensitive element. Without affecting the cold headingmachine assembly and the measurement requirements of conditions, the blank of the force isanalyzed in the die under cold heading forming process. The installation position of the sensoris determined. Piezoelectric equation is deduced to meet cold heading process. Cold headingforce is calculated. The shape parameter of PVDF piezoelectric film is obtained. The variouscomponents strength of sensor is analyzed.Third, the mechanical properties of the sensor are analyzed. A mathematical model is built.The sensor natural frequency derivation formula is deduced by stress analysis. Based on therelevant parameters of the sensor design, the theoretical natural frequency of the sensor isobtained. The structural parameter for the impact of the natural frequency law is analyzed byusing MATLAB.Fourth, a mapping relationship between the applied load and the output load is obtained byusing ANSYS. Comparison of sensor natural frequency of the simulation curve and thetheoretical curve, the factors affecting the natural frequency is verified. For the stressdistribution of the various components of the sensor, the structure parameters for influence ofthe output load is simulated. The sensor structure to improve and parameter optimization iscompletedFifth, static and dynamic calibration of the sensor platform is built. Static and dynamiccalibration method is determined. Static and dynamic index is obtained by sensor calibrationdevice.