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液压锤工作环境非常恶劣,其中活塞是受力状况最为复杂、最容易失效的零件之一。研究了液压锤活塞在工作状态下的受力状况,建立了活塞加速行程的力学模型,获得了活塞撞击钎杆前的初始运动条件;应用有限元技术对活塞撞击钎杆的过程进行了刚柔体运动、非线性接触碰撞仿真,获得了活塞的应力云图及其关键点在撞击过程的应力变化曲线。分析表明,活塞撞击钎杆的持续时间非常短暂,冲击应力非常大,导致端部存在局部应力超出材料屈服极限。为了避免活塞因端面不均衡塑性变形而导致端部边缘破损、端面与轴线垂直度破坏等情况发生,需要对活塞端部结构进行改进。该分析结果已应用于某型液压锤设计,为提高活塞的使用寿命提供了技术指导。
Hammer working environment is very bad, in which the piston is the most complex state of the force, one of the most vulnerable parts. The mechanical model of hydraulic hammer piston under working condition was studied, the mechanical model of piston acceleration stroke was established, and the initial motion condition of the piston before impacting on the drill rod was obtained. The finite element method Body motion and nonlinear contact collision simulation, the stress cloud curve of the piston and the stress curve of the key point during the impact process are obtained. The analysis shows that the duration of the piston striking the rod is very short and the impact stress is very large, resulting in the local stress at the ends exceeding the yield limit of the material. In order to avoid the piston being damaged due to the unequal plastic deformation of the end face, the end edge is damaged, the perpendicularity of the end face and the axis is damaged and the like, and the end structure of the piston needs to be improved. The analysis results have been applied to a hydraulic hammer design, to improve the service life of the piston provides a technical guidance.