滑阀节流式液体静压丝杠螺母的承载性能分析

发布时间：2018-05-18 07:23

本文选题：静压丝杠螺母 + 滑阀节流器　；参考：《山东大学》2017年硕士论文

【摘要】：丝杠螺母是数控机床等关键装备的基础功能部件,所以对于其结构设计与性能分析一直都是众多学者研究的重点。但是,之前主流研究都是集中在滚珠丝杠螺母,近年来,数控机床高速重载化、高精度化、高可靠性等特点成为新的发展趋势,与此同时,液体静压丝杠以其非接触传动、高承载力、高抗振性和高精度等优点引起了很多学者的重视。同样作为将伺服电机的旋转转换为直线运动传动部件,液体静压丝杠螺母克服了滚珠丝杠刚度不足、低速时有显著滑动、重复精度差的缺点,又不像直线电机具有控制系统复杂、自锁能力差的缺点。但是,静压丝杠螺母传动也不是十全十美之选。静压丝杠螺母也有其缺点:为了蓄油保压,静压油腔是开在螺母内螺纹面上,这使得加工制造难度极高,加工精度难以保证;同时在丝杠螺母螺纹加工过程中,不可避免的存在着螺距误差、牙型角误差、齿宽误差等加工误差,这些加工误差的存在,都会影响到液体静压丝杠螺母的承载能力、刚度、阻尼等性能。本文综合考虑到重载静压丝杠的承载能力及刚度等静态性能的要求,设计了配套的可变节流器中的滑阀节流器,并讨论分析了重要螺母参数以及螺距误差对于静压丝杠螺母静态承载性能的影响。首先,设计符合要求的丝杠螺母结构参数以及滑阀节流器的参数,数据分析相比于固定节流器中的毛细管节流器的优势所在,探究不同油腔占比,牙型半角,螺距以及油膜间隙这几个重要螺母参数对于承载性能的影响。其次,分析研究了螺母螺距误差对于静压静态承载特性的影响。分类讨论了螺距误差类型,建立了螺距误差下螺旋面间配合间隙即油膜厚度的模型。根据静压承载原理建立了供油压力、节流器节流压力、静压油腔压力和油腔封油面节流压力的平衡方程及流量连续方程,并由此研究静压承载性能。最后,研究螺母螺距误差所引起的动压效应对于承载特性的影响。建立了封油面上描述压力分布的雷诺方程,采用有限差分法,超松弛迭代法离散求解雷诺方程,联立静压油腔压力方程和流量连续性方程,结合螺距误差下油膜厚度模型,求解静压油腔压力和封油面上的动压分布,并比较对承载能力的影响。本文对于重要螺母参数对于承载性能的影响,以及螺母螺距误差对承载性能的影响,做出了具有参考意义的总结分析,希望对于液体静压丝杠螺母传动件的推广使用有一定的借鉴意义。
[Abstract]:The screw nut is the basic functional part of the key equipment such as numerical control machine tools, so the structural design and performance analysis of the screw nut has been the focus of many scholars. In recent years, the characteristics of high speed and heavy load, high precision and high reliability of CNC machine tools have become a new trend of development. At the same time, hydrostatic screw with its non-contact drive, Many scholars pay attention to the advantages of high bearing capacity, high vibration resistance and high precision. In the same way, the hydrostatic screw nut overcomes the shortcomings of insufficient stiffness of ball screw, significant sliding at low speed and poor repetition accuracy. Unlike linear motor, it has the disadvantages of complex control system and poor self-locking capability. However, the hydrostatic screw nut drive is not a perfect choice. The hydrostatic screw nut also has its disadvantages: in order to store oil and keep pressure, the hydrostatic oil chamber is opened on the inner thread surface of the nut, which makes the machining and manufacturing extremely difficult and the machining precision difficult to guarantee; at the same time, in the process of processing the screw nut thread, There are inevitable machining errors such as pitch error tooth angle error tooth width error and so on. The existence of these errors will affect the bearing capacity stiffness damping and other properties of the hydrostatic screw nut. In this paper, the sliding valve throttle in variable throttle is designed considering the requirements of static performance such as bearing capacity and stiffness of heavy load static screw. The influence of important nut parameters and pitch error on static bearing performance of static screw nut is discussed and analyzed. First of all, the structure parameters of the screw nut and the parameters of the slide valve throttle are designed to meet the requirements. The data analysis is compared with the advantages of the capillary throttle in the fixed throttle. The influence of several important nut parameters such as pitch and oil film clearance on bearing performance. Secondly, the influence of nut pitch error on static bearing characteristics of static pressure is analyzed. The type of pitch error is discussed, and the model of oil film thickness between helical surfaces under pitch error is established. According to the principle of static pressure loading, the equilibrium equations and flow continuity equations of oil supply pressure, throttle throttling pressure, static pressure oil chamber pressure and throttling pressure on oil seal surface are established, and the static pressure bearing capacity is studied. Finally, the effect of the dynamic pressure effect caused by the nut pitch error on the bearing characteristics is studied. The Reynolds equation describing the pressure distribution on the sealing surface is established. The Reynolds equation is discretized by the finite difference method and the overrelaxation iterative method, the pressure equation of the vertical hydrostatic oil chamber and the flow continuity equation are discretely solved, and the oil film thickness model under the screw pitch error is combined. The hydrostatic chamber pressure and the dynamic pressure distribution on the sealing surface are solved, and the influence on the bearing capacity is compared. In this paper, the influence of important nut parameters on bearing performance and the effect of nut pitch error on bearing performance are summarized and analyzed. It is hoped that it can be used as a reference for the application of hydrostatic screw nut drive.
【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】：TH132

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