菱形定位销的改进

Study on the location of conical floating edge cutting pin

以弯臂杆支座精镗Ф16 mm孔的工序为例,该工序除了要保证孔径精度,还要保证孔与A、B基准的位置精度。提出一种可以替代传统菱形销的新型定位销,该销是通过圆锥销进行削边处理在销底部增加了弹簧机构,利用弹簧的弹力进行浮动定位,保证这种圆锥浮动削边销与孔零间隙接触,进而消除了销孔配合间隙提高了夹具定位精度。如果圆锥浮动削边销在弹簧的弹力作用下能够顺利推进工件孔中,必须保证工件和销在这个过程中不能出现自锁现象。通过对工件进行受力分析及计算选出合理的锥度消除自锁现象。这种圆锥浮动削边销对定位孔的精度没有任何要求,但是在定位时的定位精度却比传统的圆柱削边销的定位精度要高,可以替代圆柱削边销在夹具中的作用。

Taking the process of precise boring of Ф16 mm holes on rocker arm support as an example,this process not only ensures the accuracy of holes,but also the accuracy of holes and reference dimensions A and B.A new type of positioning pin is proposed,which can replace the traditional diamond pin. The pin is edged by conical pin,and a spring mechanism is added at the bottom of the pin. The elastic force of spring is used for floating positioning to ensure the floating tapered edge pin. Contact with the zero clearance of the hole,thereby eliminating the pinhole clearance and improving the fixture positioning accuracy. If the conical floating edge-cutting pin can propel smoothly into the workpiece hole under the elastic force of the spring,it is necessary to ensure that the workpiece and the pin can not appear self-locking phenomenon in this process. Through the force analysis and calculation of the workpiece,a reasonable taper is selected to eliminate the self-locking phenomenon. The conical floating edge-cutting pin has no requirement for the accuracy of positioning hole,but its positioning accuracy is higher than that of the traditional cylindrical edge-cutting pin,which can replace the role of cylindrical edge-cutting pin in fixture.