大重型轧辊磨床砂轮主轴速度提升关键技术研究

发布时间：2018-11-02 16:39

【摘要】：大重型轧辊磨床是广泛应用于冶金、造纸、造船等行业用于大型轧辊等零件加工的关键设备。其磨削精度及磨削效率主要受其砂轮主轴转速及旋转精度影响,而砂轮主轴支撑系统的核心部件前端液体动静压径向轴承是决定其转速及旋转精度的关键。论文以贵阳险峰机床厂新研制的MK84250大重型轧辊磨床砂轮主轴支撑系统的核心部件—主轴前轴承为研究对象。主要针对其承载能力、温升等影响工作性能的关键因素进行计算和校核,获得了适合于此种特殊结构轴承的简便计算方法,并通过实验验证了计算方法的正确性;在此基础上设计了适应于MK84250砂轮主轴结构的新结构轴承,并通过计算和实验验证了结构的可行性和合理性。1、研究了MK84250在用液体动静压轴承求解过程。对轧辊磨床结构,在用液体动静压轴承典型三油腔结构进行了介绍;对轴承受力情况及轴承工作过程进行了分析,明确了轴承的受载情况并对其所受载荷进行了计算。2、研究分析了该轴承动压油膜的的求解域的确定方法,求解域的起点坐标取决于偏位角的确定。在用准二维方法求解油膜压力时,提出了一种新的简易的计算偏位角的方法。对液体动静压轴承的求解流程进行了设计和分析,并对求解过程及关键点进行了详细介绍。根据计算流程,推导雷诺方程的量纲一化公式,通过数值计算利用MATLAB工具获得了油膜的无量纲和有量纲的油膜分布情况,拟合获得了承载量系数—偏心率(S_0-ε)方程及曲线,在此基础上对45m/s和60m/s极限速度情况下轴承的承载能力及温升进行了计算和校核。同时对轴承流量、温度及刚度进行了实验检测,对检测数据的分析证明了计算过程和方法的正确性和可行性。3、论文研究分析结果表明MK84250磨床当砂轮磨削速度达60m/s时将导致主轴头部轴承温升过高而不能正常工作,这就需要对头部主轴轴承相关组件进行一系列的改进设计,才有可能解决温升过高的问题。通过分析和计算,按照改造成本最小化原则,提出了改进设计的依据和方向,对静压油腔、轴承宽度进行了改进性设计,以提高油流量,改善散热条件。设计了宽径比B/D=0.7双列窄轴承,并对静压油腔油垫的承载能力进行了校核。并对涉及到的相关零件结构进行了适应性变动,如偏心套、环形油槽等,对原静压腔毛细管节流器进行了分析计算。4、利用论文提出的方法对新结构轴承的承载能力及温升进行了计算分析,研究和计算结果表明该新结构轴承承载能力高于砂轮在45m/s速度下的原MK84250主轴轴承。新轴承在砂轮60m/s条件下其内部有效温度完全满足温度要求,且经过初步计算分析,当砂轮速度提高到70m/s时仍能正常工作。同时对新结构轴承的温升、泄油量以及刚度进行了检测试验,其数据与理论计算的数据相近,验证了新结构轴承设计的可用性。
[Abstract]:Large and heavy roller grinder is widely used in metallurgy, papermaking, shipbuilding and other industries for the processing of large rolls and other parts of the key equipment. The grinding accuracy and grinding efficiency are mainly affected by the rotational speed and rotation accuracy of the grinding wheel spindle, and the key to determine the rotational speed and rotation accuracy is the front end liquid static and static radial bearing, which is the core component of the grinding wheel spindle support system. The research object of this paper is the spindle front bearing, which is the core component of the spindle support system of MK84250 large and heavy roller grinder, which is newly developed by Guiyang Huanfeng Machine tool Factory. Based on the calculation and checking of the key factors such as bearing capacity, temperature rise and so on, a simple calculation method suitable for this special structure bearing is obtained, and the correctness of the calculation method is verified by experiments. On this basis, a new structure bearing suitable for the spindle structure of MK84250 grinding wheel is designed, and the feasibility and rationality of the structure are verified by calculation and experiment. 1. The solution process of MK84250 with liquid hydrostatic bearing is studied. The structure of roller grinder and the typical three-oil cavity structure of hydrostatic and hydrostatic bearing are introduced. The bearing stress and bearing working process are analyzed, and the bearing load is determined and the load is calculated. 2. The method of determining the solution region of the bearing dynamic pressure oil film is studied and analyzed. The starting coordinates of the solution domain depend on the determination of the offset angle. In this paper, a new and simple method for calculating the offset angle is presented when the oil film pressure is solved by using the quasi two dimensional method. The design and analysis of the solution flow of the liquid hydrostatic bearing are carried out, and the solving process and key points are introduced in detail. According to the calculation flow, the dimensionality formula of Reynolds equation is deduced, and the dimensionless and dimensionless oil film distribution is obtained by numerical calculation using MATLAB tool. The equation and curve of bearing capacity coefficient eccentricity (S _ 0- 蔚) are obtained by fitting. On this basis, the bearing capacity and temperature rise of bearing under the condition of 45m/s and 60m/s limit velocity are calculated and checked. At the same time, the flow rate, temperature and stiffness of the bearing are tested experimentally. The analysis of the test data proves the correctness and feasibility of the calculation process and method. The research and analysis results show that when the grinding speed of MK84250 grinder is up to 60m/s, the temperature rise of spindle head bearing will be too high and it can not work normally, which requires a series of improvement design for head spindle bearing related components. It is possible to solve the problem of excessive temperature rise. Through analysis and calculation, according to the principle of minimization of revamping cost, the basis and direction of improved design are put forward, and the improved design of hydrostatic oil chamber and bearing width is carried out in order to increase oil flow rate and improve heat dissipation condition. Double row narrow bearing with wide diameter ratio (B/D=0.7) was designed, and the bearing capacity of hydrostatic oil gasket was checked. The structure of the related parts is changed adaptively, such as eccentricity sleeve, annular oil tank and so on. The capillary throttle of the original hydrostatic cavity is analyzed and calculated. The bearing capacity and temperature rise of the new structure bearing are calculated and analyzed by using the method proposed in this paper. The results show that the bearing capacity of the new structure bearing is higher than that of the original MK84250 spindle bearing of the grinding wheel at 45m/s speed. The internal effective temperature of the new bearing fully meets the temperature requirement under the condition of grinding wheel 60m/s, and after preliminary calculation and analysis, when the wheel speed is increased to 70m/s, it can still work normally. At the same time, the temperature rise, oil discharge and stiffness of the new structure bearing are tested, and the data are close to the theoretical calculation data, which verifies the usability of the new structure bearing design.
【学位授予单位】：贵州大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TG595.4

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