电触点感应钎焊及控制

本文求解了适用于电触点感应钎焊的电磁场及热场耦合方程,获得了二维电触点感应钎焊的理论解,并建立了电触点感应钎焊的有限元模型,二者对比分析,验证了有限元方法分析电触点感应钎焊的可行性。数值结果表明：焊接区域的温度在靠近电触点边界的位置最高,越靠近电触点中心位置的温度越低。线圈增加铁氧体后,电触点中心位置与电触点边界位置的焊膏熔化情况更为接近,一定程度上改善了焊接面温度的不均匀分布。另外,线圈改进前后,焊接时间均随着焊接电流的增大而减少。相同焊接电流参数下,使用了缠绕有铁氧体的感应线圈只需花费更少的时间就可达到所需温升,这大大提高了电触点组件的焊接效率。因此,我们可通过在感应线圈中间增加铁氧体来改善感应钎焊温度不均匀分布,以及缩短焊接时间,从而提高电触头感应钎焊的焊接质量和焊接效率,这对电触点材料的焊接有一定的指导意义。

Analysis and Control on Induction Brazing of Electrical Contacts

Analytical solution is proposed for induction brazing of electrical contacts by solving coupled equations of electromagnetic field and thermal field. And a finite element model is presented in the paper to simulate induction brazing of electrical contact. The numerical results agree well with the analytical results. Therefore the feasibility of simulation analysis of induction brazing using finite element method is fully validated. Numerical results show that, the temperature near the boundary of electrical contacts is the highest in the brazing region. The closer to the center of brazing region, the lower the temperature. In addition, when induction coil wound with ferrite, the state of melting the solder near the center of electrical contact becomes more similar to the state near the boundary of electrical contact, accordingly nonuniform distribution of the temperature at brazing interface is improved to a certain extent. Further more, whether the induction coil optimized or not, the brazing time all decreases with the increase of brazing current. And under the same brazing current, it costs less time to obtain the required temperature rise when using the coil wound with ferrite. This indicates that the use of ferrite to optimize induction coil will improve nonuniform temperature distribution of induction brazing, which will also saving brazing time, thus improving brazing efficiency and brazing quality.This has certain instructive significance to the brazing of electrical contact material