三牙轮钻头牙轮齿孔表面装配应力测试分析

采用应力电测法对三牙轮钻头牙轮齿孔表面装配应力进行了实际测试 ,测试结果表明 :单齿压入时 ,齿孔变形将受到牙轮纵横向刚度差异的影响 ,在一定过盈量情况下 ,齿孔变形呈椭圆趋势 ;随着过盈量的增加 ,齿孔孔表的周向应力和径向应力将全部变成拉应力 ,这是导致齿孔产生裂纹的重要因素 ;邻孔压齿对测试孔装配应力有明显的影响 ,影响程度与齿孔距有关 ;齿孔计算模型以及牙轮设计和加工过程中 ,必须考虑牙轮纵横向刚度以及邻孔压齿的影响。

Test and analysis of assembly stress in the tooth holes of tri-cone bit

The assembly stress on the tooth hole surface of a tri-cone bit is tested by stress electric test method. The result of the test shows that, as a single tooth is pressed into a tooth hole, the deformation of the tooth hole is influenced by the longitudinal and lateral rigidity difference of the cone, and the deformation of the tooth hole tends to an ellipse under a certain magnitude of interference. With the increase of the magnitude of interference, the circumferential stress and radial stress on the surface of the tooth holes will change into tensile stress, and this is the key factor leading to cracks in the tooth holes. Pressing tooth in the adjacent hole inflences obviously the assembly stress in the test holes, and the influence degree is related to the distance between the two holes. Therefore the influence of the longitudinal and lateral rigidity of the cone and tooth pressing in the adjacent holes must be taken into account in the design and machining of the cone.