新型单面薄膜节流阀的性能与应用研究

发布时间：2018-06-11 19:30

本文选题：压电陶瓷 + 薄膜节流器　；参考：《山东大学》2017年硕士论文

【摘要】：非圆曲面因具有改善润滑,均布载荷,减小集中应力,提高使用寿命等优点,被广泛应用于高品质零部件。然而,对非圆曲面的精密加工一直是现代制造技术中的关键难题,特别是对非圆内孔的精密加工更具有挑战性。本文设计了一种新型单面薄膜节流阀,用于静压主轴轴心轨迹的主动控制,为实现非圆内曲面的精密加工提供新的加工方法。开展了径向静压轴承的理论研究,推导了四油腔静压轴承的雷诺方程、流量连续方程等基础方程,并给出了其计算方法。对比了有周向回油槽四油腔静压轴承与无周向回油槽四油腔静压轴承的结构特点和压力分布。使用简化算法计算了有回油槽静压轴承的静态特性,并通过算例验证了其实用性。设计了一种压电陶瓷致动器驱动的新型单面薄膜节流阀,分析了其工作原理和结构优势,并建立了新型单面薄膜节流阀的理论模型。研究了其压力和流量特性,给出了薄膜刚度的计算公式,进行了薄膜的受力分析。将新型单面薄膜节流阀结构参数优化设计问题从复杂的多目标优化简化为单目标非线性优化问题,并使用matlab软件的优化工具箱中fmincon函数优化设计了新型单面薄膜节流阀的结构参数。介绍了两种静压主轴主动控制液压系统的设计方案,分别仿真了期望轴心轨迹与压电陶瓷致动器输出位移、推力之间的关系,并对两种系统设计方案进行了对比分析。推导了静压轴承的刚度和阻尼求解方法,分析了主轴偏心率、供油压力对静压轴承油膜刚度系数和油膜阻尼系数的影响。构建了新型单面薄膜节流阀独立控制的静压主轴系统的动力学模型,给出了系统传递函数,并仿真了系统的阶跃响应。搭建了新型单面薄膜节流阀的实验系统。实验得出了压电陶瓷致动器的静态特性和迟滞特性,使用基于LM算法的BP神经网络模型预测了压电陶瓷致动器的输出位移。实验得出了新型单面薄膜节流阀的动态响应特性和流量特性,并拟合出了节流阀的流量公式。
[Abstract]:Non-circular surface is widely used in high quality parts because of its advantages of improving lubrication, distributing load, reducing concentration stress and increasing service life. However, the precision machining of non-circular surfaces has always been a key problem in modern manufacturing technology, especially for the precise machining of non-circular inner holes. In this paper, a new type of single-sided thin-film throttle valve is designed, which is used for the active control of the axial trajectory of the hydrostatic spindle, and provides a new machining method for the precision machining of the non-circular inner surface. The theoretical study of the radial hydrostatic bearing is carried out. The Reynolds equation and flow continuity equation of the four oil cavity hydrostatic bearing are derived and the calculation method is given. The structure characteristics and pressure distribution of the hydrostatic bearing with circumferential return tank and four oil chamber with no circumferential oil return groove are compared. The static characteristics of hydrostatic bearing with return tank are calculated by simplified algorithm, and its practicability is verified by an example. A new type of single-sided thin film throttle driven by piezoelectric ceramic actuator is designed, its working principle and structural advantages are analyzed, and the theoretical model of the new single-sided thin-film throttle valve is established. The pressure and flow characteristics of the film are studied, the calculation formula of the film stiffness is given, and the stress analysis of the film is carried out. In this paper, the problem of structural parameter optimization for a new type of single-sided thin-film throttle valve is simplified from complex multi-objective optimization to single-objective nonlinear optimization problem. Using the fmincon function in the optimization toolbox of matlab software, the structural parameters of a new type of one-sided thin-film throttle valve are optimized. This paper introduces two design schemes of hydrostatic spindle active control hydraulic system, simulates the relationship between the expected axis trajectory and the output displacement and thrust of the piezoelectric actuator, and makes a comparative analysis of the two design schemes. The stiffness and damping methods of hydrostatic bearing are derived, and the effects of spindle eccentricity and oil supply pressure on the film stiffness and damping coefficient of hydrostatic bearing are analyzed. The dynamic model of a new type of hydrostatic spindle system controlled independently by a single side thin film throttle valve is constructed. The system transfer function is given and the step response of the system is simulated. A new experimental system of single-sided film throttle valve is set up. The static and hysteresis characteristics of piezoelectric actuator are obtained experimentally. The output displacement of piezoelectric actuator is predicted by BP neural network model based on LM algorithm. The dynamic response characteristics and flow characteristics of a new type of single-sided thin-film throttle valve are obtained experimentally, and the flow formula of the throttle valve is fitted.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TH137.522

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