支架(永磁组合)是磁电系电表的关键件之一,图1所示,它是由极靴磁钢用ZL107铝硅合金压铸制成的。图1支架简图零件要求两个螺纹孔与组合的极靴外径同轴度允差不大于RO.06;而极靴与磁钢组合的直径公差值为0.20毫米。这样从工艺分析可知,如果在压铸加工中靠模具将螺纹底孔制出,是无法保证螺纹底孔与极靴间的同轴 Bracket (permanent magnet combination) is one of the key parts of the magnetoelectric meter, shown in Figure 1, which is made of ZL107 aluminum-silicon alloy die-cast magnet of the pole shoe. Figure 1 bracket schematic parts require two threaded holes combined with the pole piece outer diameter coaxial tolerance less than RO.06; and pole shoe and magnet combination of diameter tolerance value of 0.20 mm. This process from the analysis shows that, if the die-casting process by the bottom hole will be made of thread, it is impossible to ensure that the bottom hole and the pole thread between the coaxial