螺纹配合偏差对引信内腔封口螺纹连接强度的影响

摘要

In view of fuze inner connection sealing strength design,according to the calculation formula of thread stress,The external thread has four level grade of tolerance and six level grade of tolerance and internal thread get six level grade of tolerance.Tolerance zone is e、f、g、h,.made tolerance zone become a only variable through control variate method to calculate the influence of thread fit deviation.The solution showed that:in difference position of the tolerance zone,Relation increment of the shear stress of thread is larger than the rela-tion increment of bending stress.The value of relation increment of the shear stress become larger and the value of relation increment for the bending stress getting smaller with the increase of diameter of the screw thread;With a decrease of basic deviation,the value of relation increment is getting smaller.When the basic deviation is esh,the value of relation increment about the shear stress and bending stress become zero;when the grade of tol-erance is four level,the increment of stress of shear and bend is smaller than the grade of tolerance is six.The stress of shear and bend have a great reduce when thread fit relation from 6H/6f to 6H/6g.Recommended the fit relation 6H/6g.%针对引信内腔封口螺纹公差带位置的变化和牙型半角误差对螺纹所受应力影响的问题,根据螺纹应力计算公式,以外螺纹常选用6级和4级公差等级、内螺纹常选用6级公差等级、公差带位置为e、f、g、h的配合为例,通过控制变量法,取公差带为唯一变量计算得出螺纹配合偏差对引信内腔封口螺纹连接强度的影响.结果表明,不同公差带位置情况下,螺纹剪切应力相对增量大于弯曲应力相对增量;随着螺纹直径的增大,剪切应力相对增量逐渐增大,弯曲应力相对增量逐渐减小;随着基本偏差的减小,剪切应力和弯曲应力相对增量逐渐减少.当基本偏差为 esh时,剪切应力和弯曲应力增量为0;4级公差时外螺纹剪切应力与弯曲应力增量小于6级公差外螺纹应力增量.配合从6H/6f变为6H/6g时,螺纹剪切应力和弯曲应力相对增量均有大幅度降低.推荐使用配合6H/6g.