As a new type of downhole power tool for gas drilling,the self-rotating air hammer breaks rocks by simultaneous impact and rotation.The piston of self-rotating air hammer broke several times during test.In this paper,the load of the piston impacting on the bit is analyzed by dynamic simulation,through analysis of the bro-ken piston of self-rotating air hammer.The piston strength is improved by optimizing its structure based on simu-lation results.The stress of optimized structure is in a downward trend throughout the entire impact stroke with the most significant decrease at 0.6 ms,the stress of improved structure is reduced by 43.9％compared to the previ-ous one.The improvement effect is significant.During the subsequent on-site tests of the self-rotating air hammer,there was no broken piston,which has verified the effectiveness of dynamic simulation and structural optimiza-tion.
维普
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