摘要
在航空薄壁件的加工过程中,由于材料去除率大会导致工件质量变化剧烈(简称"负载变化"),使得丝杠传动系统的驱动负载变化较大,进而影响传动系统的动态性能。为获得机床传动系统的时变特性,首先对考虑负载变化和导轨滑块副摩擦特性的传动系统进行动力学物理模型等效,并采用集中参数法建立动力学模型。理论分析了传动方向等效阻尼系数随负载变化的变化规律和不同负载下传动系统的固有频率和加速度振动响应的变化规律。理论分析结果表明,机床传动系统的动态性能在工件材料大切除率加工过程中存在着时变动特性。传动系统的等效阻尼系数随着负载的减小而减小,固有频率和加速度振动响应幅值则随负载的减小而增加,并且都具有很强的非线性行为。最后通过模态测试实验验证了理论分析的正确性。
The workpiece mass varies greatly due to large material removal rate when machining aeronautical thin-walled members.The driving force of screw transmission system of a machine tool also changes greatly,this load variation can affect the transmission system dynamic charateristics.In order to obtain the time-varying dynamic behavior of the machine tool transmission system,a dynamic model of the transmission system was established using the lumped parameter method considering load variation and friction characteristics of the slide block.The equivalent damping coefficient in feed direction was theoretically analyzed with the load variation.And the evolution of natural frequencies and vibration responses of the transmission system was studied under different loads.The results showed that the time-varying dynamic characteristics of the transmission system of the machine tool exist during machining with a large material removal rate;the equivalent damping coefficient decreases with decrease in the load,but the natural frequencies and acceleration vibration amplitude increase with decrease in the load,these variations are strongly non-linear.Finally,modal tests were performed to validate the correctness of the theoretical analysis.
出处
《振动与冲击》
EI
CSCD
北大核心
2014年第9期173-178,共6页
Journal of Vibration and Shock
基金
国家重点基础研究发展规划资助项目(973计划-2009CB724407)
国家自然科学基金重点资助项目(51235009)
关键词
传动系统
动力学模型
负载变化
时变动特性
transmission system
dynamic model
load variation
time-varying dynamic characteristics
