圆形与椭圆线圈在平板电磁成型中的应用比较

通过对椭圆形线电流产生的磁感应强度的推导,得出椭圆线圈所产生的磁感应强度的分布规律,并进一步得出圆线圈所产生的磁感应强度的分布规律,以及工件所受的磁场力的分布规律.进行了两组实验:采用小孔模具,用圆形与椭圆形线圈进行成型,比较了两个工件的变形深度;采用盒形模具,用圆形与椭圆形线圈进行成型,比较了两个工件在中心部位的变形以及长度方向的变形充分程度.结合磁感应强度的分布规律对实验结果进行分析,得出了两种线圈的适用情况:对于长形工件,采用椭圆线圈要优于圆形线圈;对中心部位变形要求较高的工件,应尽可能采用圆形线圈.

Application Comparison of the Circular and Elliptic Working Coil Used in Sheet Metal Electromagnetic Forming

In the sheet metal electromagnetic forming, the shape and dimension of the working coil directly affect the force applying on the sheet metal and have a key function for the deforming result. Here, the distribution of the magnetic induction intensity of the elliptic working coil is achieved through the deduction of the magnetic induction intensity generated by elliptic line current, and further the distribution of the magnetic induction intensity of the circular working coil and the distribution of the electromagnetic force that applies on the sheet metal are also achieved. Two groups of experiments are performed. The first, the sheet metals are deformed by using the hole mould, and the circular and elliptic working coil are respectively used. The deforming depths of the two parts are compared. The second, the sheet metals are deformed by using the rectangular mould, and the circular and elliptic working coil are respectively used. The deforming of the center position and the deforming sufficiency along the length of the two parts are compared. By the analysis of the experiment results after considering the distribution law of the magnetic induction intensity, the authors can get the suitable condition about when the two kinds of working coil are used: for a long workpiece, the elliptic working coil is better than the circular working coil; for the piece which has much demand for deforming in the center position, the circular working coil is better.