轴承跑外圈一般是因为配合的精度不够以及外圈定位方式设计不合理造成的。一般来说，螺杆机头的设计已经大同小异，结构上已不存在设计问题，出现跑外圈主要是个别机头零件加工超差造成。当然出现这种现象维修是非常困难的，因为一但跑外圈必然会导致轴承孔磨损加大，从而其配合更无法达到设计要求。大家可以通过不同的结构来想想具体的解决办法。
Generally speaking, the bearing running outer ring is caused by the insufficient matching accuracy and the unreasonable design of the outer ring positioning mode. Generally speaking, the design of the screw head has been the same, and there is no design problem in the structure. The outer ring running is mainly caused by the processing over tolerance of individual head parts. Of course, this phenomenon is very difficult to maintain, because once running the outer ring will inevitably lead to the increase of bearing hole wear, so its matching can not meet the design requirements. You can think about specific solutions through different structures.