冲击机具凿入过程的能量传递

Energy transmission in penetration process of percussive machines

冲击机具凿入过程的能量传递是冲击凿入系统的核心问题。针对大多数冲击凿入系统采用单圆柱活塞的情况,得出了单圆柱活塞凿入系统的能量传递效率表达式,阐明了冲击凿入的二重能量转化过程及在活塞和工具中的残留能量,并分析了系统参数对其的影响。研究表明:在二重能量转化过程中,系统凿入效率η为入射波有效转化效率ηi和凿入转化效率ηR之积;在系统常数q=0,1<θ<2.5情况下,具有最佳效率区间(η>75%);残留能量在q≥0时较低,在q<0时,随q值的减少急速增大;残留能量的增大将影响凿入系统的正常工作和疲劳寿命。以冲击能量传递试验系统上的试验作为计算实例,计算和测试结果基本一致。

The energy transmission in percussive machines’ penetration process is a key problem of percussive systems. Here,for general percussive penetration systems with a single cylinder piston,the expression of energy transfer efficiency for a percussive system with a single cylinder piston was derived. Furthermore,the dual energy conversion process and residual energy in piston and tools were presented with the wave theory. Influences of system parameters on energy transmission were analyzed. The study showed that in the dual energy conversion process,the system penetration efficiency η is a product of the incident wave effective conversion efficiency and the penetration conversion efficiency;there is an optimal region for η（ η 〉 75%） when the system constant q = 0 and 1 〈 θ 〈 2. 5; the residual energy is lower when q≥0,but it increases rapidly with decrease in q when q 〈 0; increase in the residual energy affects normal operation and fatigue life of a percussive system. Taking tests on a percussive energy transmission test system as examples,the results of calculation agree well with those of tests.