Research On Supported PVDF Three-Dimensional Force Sensor For Cold Heading Of Steel Ball

As the "joint" of modern mechanical equipment,bearing plays an important role in the construction of the national economy.Bearing rolling element is the core part of bearing,and its manufacturing quality directly determines the running performance of bearing.As the most commonly used bearing rolling element,the improvement of its detection level can promote the rapid development of the bearing industry.As the first process of steel ball processing and production,cold heading is essential,which must be monitored by effective means.The signal characteristics of cold heading force can reflect the production status of the steel ball cold heading machine,but the current force measuring sensor has certain limitations,which can not fully meet the requirements of heavy load,high dynamic and three-dimensional force measurement in cold heading force measurement.Therefore,the research on supported PVDF three-dimensional force sensor for cold heading of steel ball is carried out.Firstly,the mathematical model of the movement law of the upper die on the steel ball cold heading machine is established.By using DEFORM simulation software to calculate and analyze the cold heading process of steel ball,the real-time load signal of the bottom die on the cold heading machine in the process of cold heading forming is obtained,and the internal change law of the bottom die load is found,which proves the feasibility of monitoring the quality of steel ball cold heading by extracting the bottom die load signal.Secondly,according to the characteristics of the load signal of the bottom die in the steel ball cold heading process,the characteristics of different piezoelectric materials are compared,and the appropriate force-sensitive elements are selected.Combined with PVDF piezoelectric film three-dimensional force measurement principle,force sensor layout analysis,sensor parallel load sharing principle and PVDF piezoelectric film area segmentation technology,using the method of theoretical analysis and ANSYS simulation analysis,the scheme design of supported PVDF three-dimensional force sensor for cold heading of steel ball is completed.Thirdly,based on the mechanism modeling method,the static and dynamic mathematical model of PVDF piezoelectric film three-dimensional force sensor is established,and the calculation formulas of force electric conversion efficiency,charge sensitivity and natural frequency of the sensor are obtained.The influence of the structural parameters of the sensor on its static and dynamic performance is analyzed by MATLAB software.The overall dimension of the sensor is determined.Finally,the static simulation analysis of the sensor is carried out by using ANSYS software,and the relationship curve between the input and output of the sensor under the three-dimensional force and the charge sensitivity are obtained;the natural frequency of the sensor is obtained after the modal analysis of the sensor.When any three-dimensional force is applied to the PVDF three-dimensional force sensor which meets the design requirements,it is found that the actual input load of the sensor is highly consistent with the output load from the decoupling calculation.