【摘要】 潜孔柱齿钻头在工作中遇到较多的问题是钻头体断裂和合金柱齿脱落,造成使用寿命不长。本文在对钻头中冲击渡所作分析的基础上,探讨了钻头体断裂和合金柱齿脱落的原因。当钻头的长度大于活塞时,钻头中将出现反射波不与主冲击波重迭的部位,可能出现拉应力,在较大拉应力的区域内,容易产生疲劳和断裂破坏。在凿岩过程中,由于岩石的破碎情况不同,将产生不同的反射波,使合金柱质点的运动速度与邻近的钻头中质点速度不一致,当合金柱速度较大时就可能有脱出的趋势。根据以上分析,推导出钻头体中冲击应力和脱出力的计算公式,从而为设计钻头体几何形状和选择合金柱过盈配合尺寸提供了理论判据。更多还原

【Abstract】 The cracking of the bit body and the loosening of bit button often constitute a major problem of DTH bit which certainly shortens the service life of the bit. This article based on the analysis of the shock wave inside the bit is intended to find out the causes of the above mentioned problems. When the length of thl bit is longer than that of the piston, the tension stress will appear in such area, where the reflection wave and the main shock wave inside the bit do not overlap one another. Hence, inside this area the metal fatigue and cracking of the bit could occur.During the process of drilling, the various types of reflection wave will be resulted from different kind of breakage of rocks. It causes different particle velocity between the particles of bit button and the bit body. If the particle velocity of the bit button is faster than that of the bit body, a tendency of loosening bit button could occur. According to this analysis, we have derived a formula for calculating the shock stress of bit body and the loosening force of the button. This formula provides us with a theoretical criterion for designing the geometric configuration of the bit body and selecting surplus volume for fitness of bit button.更多还原