数控机床主动力系统载荷能量损耗系数的计算获取方法

机床量大面广,能量消耗巨大并且能量效率低、能量效率规律复杂,因此机床能量效率的研究和应用正在全球迅速兴起。机床主动力系统载荷能量损耗,是机床最复杂的部分,一般占到机床切削能量的10%~20%,其具体多少决定于载荷损耗系数。针对机床主动力系统载荷损耗系数在线获取非常困难,以及现有获取方法存在切削仪器昂贵、测量过程复杂以及许多机床无法安装等不足,提出一种根据数控机床主动力系统载荷能量损耗数学模型而建立的载荷损耗系数计算获取方法。上述数学模型由三部分组成:基于主电动机的变频器额定功率、额定功率损耗和散热器额定功率等基础参数的变频器功率损耗近似计算模型;基于主电动机额定功率、基频、空载功率和基频下的效率等基础参数的主电动机功率损耗模型;基于机床机械传动系统中每种传动副的数量和载荷效率等基础参数的机械传动系统载荷损耗模型。实际计算时只需获取基础参数和测量机床主动力系统空载功率,便可计算出机床主动力系统的载荷能量损耗系数。基于上述计算方法,计算获取了数控加工中心PL700主动力系统的载荷能量损耗系数。实验结果证实了该方法的准确性和实用性。该方法可广泛用于数控机床的切削功率获取、数控机床能量效率评价和工件能量效率预测及优化等研究和应用中,具有多方面的应用前景。

Calculating Method for Additional Load Loss Coefficient of Spindle System of CNC Machine Tools

Machine tools are in enormous quantity and consume substantial amounts of energy, but the energy efficiency of machine tools with complicated laws is very low. Therefore, the researches and applications of machine tools’ energy efficiency are attracting more and more attentions on the international scene in recent years. The additional load losses, determined by additional load losses coefficient, are of great importance for investigating the energy efficiency of machine tools because those account for 10%-20% of the cutting power. To solve the difficult acquisition of additional load losses coefficient on the scene, based on the mathematical model of the additional load losses, proposes a method to calculate the additional load losses coefficient of spindle system of CNC machine tools. The mathematical model include three models: The approximate calculation model of inverter’s power loss which is based on the basic parameters of the rated power, rated power loss and cooler’s rated power of inverter; the power loss model of main motor which is based on the basic parameters of the rated power, fundamental frequency, the idle power loss and efficiency under the fundamental frequency of spindle motor; the mathematical model of the additional load losses of main transmission system which is based on the basic parameters of the number of transmission-countershaft’s type and the efficiency of each type of transmission-countershaft. To calculate the additional load losses coefficient on the scene, we just need obtain the basic parameters and measure the idle power of spindle system. According to the calculating method, the additional load losses coefficient of the spindle system of CNC machining center PL700 is calculated. The experiment results show the accuracy and practicability of the proposed method. This calculating method can be widely applied to obtain the cutting power and analyze the energy efficiency of CNC machine tools, predicting and optimizing the energy efficiency of work piece, and so on.