摘要
针对磁悬浮铣削电主轴在切削加工过程中因切屑不断进入、离开刀具容屑槽导致系统质量大小和分布不断变化,进而引起系统动力学特性的非线性变化问题,首先,依据金属连续切削原理求得单个切屑质量,并结合连续梁振动理论,应用有限单元法建立“磁悬浮轴承-电主轴-刀具-切屑”时变质量系统的动力学模型;然后,采用龙格库塔法对系统的运动微分方程进行求解,分析切屑从进入到离开容屑槽的整个过程,切屑质量变化对系统固有频率、振型的影响规律;进而探索由时变切屑质量所引起的旋转惯性载荷、陀螺力矩、切削力、磁悬浮轴承电磁力等激励下的系统振动响应规律;最后,利用MATLAB软件对系统进行仿真求解.结果表明:切屑质量从0增大到2.08×10^(-5)kg时,系统前三阶临界转速分别下降约2.3、0.7、0.3 r/min,可知时变切屑质量对系统固有特性影响较小;旋转惯性载荷对系统的动态响应有较大影响,尤其是对切削加工点,使切削点的径向振动响应和角向振动响应的幅值分别出现0~9.7×10^(-7)m和0~2.5×10^(-5)rad不等的增大,还使加工点处径向振动和角向振动平衡位置的偏移距离分别增加约5.1×10^(-7)m和9.3×10^(-6)rad.
As chips continuously enter and leave from the tool flute during the cutting process of the motorized spindle for magnetic suspension milling,the size and distribution of the system mass are constantly changing,leading to the nonlinear change of system dynamics characteristics.To address these issues,firstly,the mass of a single chip was calculated based on the principle of continuous metal cutting,and then combined with the theory of continuous beam vibration,the dynamics model of the“magnetic suspension bearing–motorized spindle–tool–chip”time-varying mass system was established by using the finite element method.Secondly,the Runge-Kutta method was used to solve the differential equation of motion of the system,and the influence of chip mass change on the natural frequency and mode shape of the system was analyzed during the entire process covering the chip’s entry into and leave from the tool flute.Then,the vibration response patterns of the system under the excitation of rotational inertial load,gyroscope torque,cutting force,and electromagnetic force of magnetic suspension bearings caused by time-varying chip mass were explored.Finally,the MATLAB software was used to simulate and solve the system.The results show that as the chip mass increases from 0 to 2.08×10^(-5) kg,the system’s first three critical speeds decrease by about 2.3,0.7,and 0.3 r/min,respectively,indicating that the time-varying chip mass has a small effect on the system’s inherent characteristics.The rotational inertia load has a significant impact on the system’s dynamic response,especially at the cutting point,causing the radial vibration response and angular vibration response amplitudes at the cutting point to increase by 0–9.7×10^(-7)m and 0–2.5×10^(-5) rad,respectively,and it makes the radial vibration and angular vibration equilibrium positions at the cutting point to increase by about 5.1×10^(-7)m and 9.3×10^(-6)rad,respectively.
作者
康辉民
席家乐
刘厚才
段良辉
KANG Huimin;XI Jiale;LIU Houcai;DUAN Lianghui(School of Mechanical Engineering,Hunan University of Science and Technology,Xiangtan 411201,China;Numerical Control Processing Branch of Jiangnan Industrial Group Co.,Ltd.,Xiangtan 411207,China)
出处
《西南交通大学学报》
北大核心
2025年第4期954-964,共11页
Journal of Southwest Jiaotong University
基金
国家自然科学基金项目(51875198)
湖南省教育厅重点项目(23A0360)。
关键词
磁悬浮电主轴
时变质量
旋转惯性特性
固有特性分析
振动响应
motorized spindle of magnetic suspension
time-varying mass
rotational inertial characteristic
inherent characteristic analysis
vibration response
