基于摩擦影响的圆柱滚子轴承温度场分析

以圆柱滚子轴承为研究对象,采用ANSYS Workbench软件对其进行静力学分析得到滚动体在不同位置与内滚道的接触应力;采用ADAMS软件对其进行动力学分析得到滚动体在不同位置与内滚道的摩擦力与正压力,进而通过Workbench分析得到滚子与内滚道的接触应力。根据静力学分析和动力学分析得到的接触应力分别求得轴承内部的摩擦热量,分析轴承的温度场。结果表明:轴承最高温出现在径向方向最下端的滚子与内滚道接触的位置;摩擦热流量与对流换热系数是影响轴承温度的2个主要因素;基于动力学得到的轴承温度场分布更加符合实际情况。     

满滚子圆柱滚子轴承

满滚子圆柱滚子轴承有单列、双列和多列(3至8列)几种结构型式。满滚子轴承的(D-d)/B值较低,能承受较重的径向载荷(例如钢铁企业联铸机、拉矫机的拉辊支承轴承译者注)。当然与有保持架的圆柱滚子轴承相比,其所能适用的转速要低。满滚子轴承的运动学条件不如有保持架的轴承,满滚子轴承中滚子与滚道以及滚子与滚子之间的摩擦和滑动阻力都很大,这就增加了轴承的磨损,因此满滚子轴承在应用上受到了一定限制。为减少轴承失效的危险和提高其可靠性,SKF公司设计并制造了滚子表面经过特殊处理的满滚子轴承,其轴承代号后缀为“B”。特殊处理后可改…     

高速轻载圆柱滚子轴承分析

采用拟动力学模型,考虑轴承中的各种接触力和摩擦力相互作用,滚子的自转、公转速度随其装置变化而变化,建立起一组动力学微分方程,并利用非线笥方程组求解方法求解,模拟出了轴承在运转中其滚动体的自转、公转速度,滚子的倾斜、歪斜及打滑等状态参数,其结果与国外的结果相吻合。     

圆柱滚子轧机轴承的改进

三列圆柱滚子轧机轴承在生产上存在端面易烧伤、轴承易碎裂的问题。为此提出用双列圆锥滚子轴承或带平挡圈的双列圆柱滚子轴承 ,替代原三列圆柱滚子轴承 ,但都不能满足实际应用 ,最后采用改进型带平挡圈的双列圆柱滚子轴承取得了满意效果。附图 1幅     

现代圆柱滚子轴承设计

经改善钢材质量、采用塑料保持架、改进挡边结构及凸度滚子的应用 ,可使圆柱滚子轴承的寿命和性能大幅度提高。介绍了建立目标函数、确定约束条件、对滚子的直径、长度及数量和最大额定动载荷等参数的优化设计 ,着重对滚子的凸度设计和保持架的选用作了说明。附图 3幅 ,表 1个。     

多列圆柱空心滚子轴承

一、背景 1897年米勒(Miller)获得一项滚子轴承专利,其中滚子由螺旋缠绕的金属片制成。从那以后90年间曾发表过许多有关的专利。它们大致可分三类: (1)利用空心滚子的弹性,吸收作用于轴承上的冲击载荷。 (2)利用空心滚子减少滚子重量,因而减少高速轴承中滚子的离心力,改善轴承寿命;利用空心滚子变形装配产生的预加负荷使滚子紧压在轴承内外滚道上,阻止高速轴承中滚子轻载工作时打滑以及用它来驱动轴承保持器。 (3)美国威拉尔·波文首先发现了预加载荷、无保持器、满装的圆柱空心滚子轴承具有高回转精度、高刚度及高速运转性能。其滚子的空…     

高速动车组轴箱轴承温度场分析

研究了圆锥滚子轴承的热分析理论,并在此基础上分别采用有限元仿真法和热网络法对圆锥滚子轴承的稳态温度场进行了分析,从宏观和微观两方面确定了轴承在工作过程中的温度场分布情况,得出轴承工作过程中温度最高点出现在轴承最下端的滚子与内圈接触处。     

圆柱滚子轴承滚子凸度量的有限元分析

用有限元方法对某汽车用圆柱滚子轴承的修形滚子的凸度量进行研究，分析凸度量对接触应力和等效应力的影响，并确定了最佳凸度量。     

A Noise Analysis of Cylindrical Roller Bearings Operating Under Zero External Load

The purpose of this article is to numerically investigate one source of acoustic noise in roller bearings, that which results from the motion of the rollers in the bearing under zero external load. For the sake of simplification, it was assumed that the cylindrical roller bearings are infinitely long. Furthermore, the effects of the following on the noise of the bearing were also examined: the radial clearance of the bearing, the viscosity of the lubricant, and the number of rollers. The results of the study show that the fundamental frequency of the noise components of the cylindrical roller bearing corresponds to the multiplication of the number of rollers and the whirling frequency of the roller center. The acoustical frequency spectra of the cylindrical roller bearing are pure tone spectra, containing the fundamental frequency of the roller bearing and its superharmonics. The factors that decrease the sound pressure level of a cylindrical roller bearing include low lubricant viscosity, high radial clearance, and a reduced number of rollers. The results and discussions of the present article could aid in the design of low-noise cylindrical roller bearings.     

预负荷空心圆柱滚子轴承刚度分析

根据预负荷空心圆柱滚子轴承变形协调条件,建立了轴承内圈的平衡方程,运用卡氏定理确定了滚子的负荷和变形间的关系式,据此导出了预负荷空心圆柱滚子轴承的刚度计算公式,依据此公式对某型号轴承刚度进行分析研究,结果表明:预负荷空心圆柱滚子轴承的刚度与外载荷无关,且随着空心度的增大而减小,随着滚子个数的增加而增大。     

Optimized Logarithmic Roller Crowning Design of Cylindrical Roller Bearings and Its Experimental Demonstration

A logarithmic profile is essentially an optimal geometry for rolling machine elements such as bearing rollers and raceways. Under most conditions of loading, it yields lower stresses to give longer endurance. Lundberg first suggested the basic profile, and some researchers followed him by modifying it to satisfy engineering requirements. In this article, the authors propose a mathematical optimization method for logarithmic profiles in roller bearing applications. Moreover, rolling contact fatigue life tests are carried out to make a comparison among logarithmically crowned, standard partially crowned, and modified partially crowned rollers. Results show that the logarithmically crowned rollers are beyond the modified partially crowned rollers in fatigue life, especially in poor lubrication conditions, although the logarithmic rollers require less workload to process the crowning.     

On the Dynamics of Lubricated Cylindrical Roller Bearings,Part II: Linear and Nonlinear Vibration Analysis

This article is the second part of two companion papers. In the first article, curve-fitted relations of stiffness and damping coefficients of a single roller-to-race contact of lubricated roller bearings were developed. In the present work, these relations are applied to a rotor–bearing system. Two cases are studied to investigate the influence of lubricated cylindrical roller bearings on the vibration characteristics of the rotor system. In the first case, lubricated contacts are simulated as a linear spring–damper model. The overall stiffness and damping matrices are calculated by using the dynamic coefficients of individual load sharing rollers. These matrices are used in the finite element analysis of flexible rotor. In the second case, the nonlinear structural vibration of a lubricated cylindrical roller bearing is studied. Equations of motion of bearing elements are derived using the Lagrange equation. A nonlinear load–deflection contact model developed through the derived curve-fitted relations of dynamic coefficients is used in the equations of motion. Equations of motion are solved by a fourth-order Runge-Kutta integration method. The response of bearing elements under free vibration and due to rotating unbalance is studied for damped and undamped cases. Furthermore, results obtained using elastohydrodynamic finite and infinite contact theories are compared.     

On the Dynamics of Lubricated Cylindrical Roller Bearings,Part I: Evaluation of Stiffness and Damping Characteristics

The stiffness and damping coefficients of a single roller-to-race contact of lubricated cylindrical roller bearings are numerically evaluated using a linearized perturbation method for both elastohydrodynamic lubrication (EHL) finite and infinite contact theories. A steady-state pressure equation is solved by a multilevel method and the elastic deformation is evaluated with the multilevel multi-integration method. Dynamic pressures are obtained by solving a set of perturbed pressure equations and are used to calculate the stiffness and damping coefficients. The influence of various nondimensional parameters (load parameter, speed parameter, material parameter, edge radius, and geometrical parameter) on the stiffness and damping are studied. The results show that a finite line contact gives higher values of stiffness and damping coefficients compared to an infinite contact, particularly at higher load and lower speed values. Based on the numerically evaluated data, curve-fitted relations for the stiffness and damping coefficients of a single roller-to-race contact are developed that can be used in the dynamic analysis of rotor–bearing systems.     

A Fatigue Life Comparison of Two-Row Tapered Roller Bearings and Spherical Roller Bearings

Tests were run to compare the fatigue life of two-row tapered roller bearings to that of spherical roller bearings. Both bearing types had an outer diameter of 110 mm with the spherical roller bearing having a 22 percent larger dynamic radial load rating than the tapered roller bearings. All tests were run at 165 percent of the respective two-row dynamic radial load ratings. The results show that both the indirect mounting (double cup or outer ring) and the direct mounting (double cone or inner ring) tapered roller bearings gave significantly better fatigue lives than the spherical roller bearings. These results appear to contradict the present ISO 281 standard which assigns a 1.15 b_m rating factor to spherical roller bearings compared to a b_m rating factor of 1.10 for that of tapered roller bearings.     

Theoretical Analysis of High-Speed Cylindrical Roller Bearing with Flexible Rings Mounted in a Squeeze Film Damper

For high-precision mechanical systems such as gas-turbine engines that operate under extreme conditions, it is particularly important to accurately predict the behavior of the mainshaft rolling bearings. This prediction includes, among others, the load distribution, stiffness, and power dissipation. Although the shaft speeds tends to increase, rings and shaft are becoming thinner due to size and weight constraints. Thus, the bearing behavior is now dependent on the housing and ring stiffness. Furthermore, the use of a squeeze film damper (SFD) is widespread in gas-turbine engines to significantly reduce the vibratory levels. In this case, a single thin ring provides the interface between the bearing rolling elements and the fluid film. Due to the flexibility of this ring, an elastic coupling occurs modifying the behavior of the bearing-SFD system. A global flexible bearing-SFD assembly model is proposed in this paper. Large deformations can occur, resulting in a contact between the ring common to the bearing and the SFD and its housing. To reproduce this interference, an effective mechanical stop model is also proposed. The behavior of an industrial bearing-SFD assembly is then investigated for different operating conditions. The presented results show that this coupling has a first-order influence on the behavior of the bearing-SFD system. It is also shown that such elastic coupling introduces a dissymmetry of the load distribution with respect to the applied load direction. Moreover, in certain cases, the position of the bearing in its housing can reach eccentricities larger than the radial clearance of the SFD.     

运行过程中转速变化时可倾瓦推力轴承油膜温度瞬态变化规律的实验研究

本文实验研究了可倾瓦推力轴承在运行过程中的不同载荷下、不同升速时间下从起始转速８００ｒ／ｍｉｎ升到截止转速５０００ｒ／ｍｉｎ时油腊温度和油膜厚度变化值的瞬态变化规律。实验时,在瓦块进油、出油边及油腊与瓦块接触面上布置了若干根铜－康铜热电偶和电涡流传感器。实验表明大运行过程中。转速升高时,不同的升速时间对油膜温度、进油边温度、出油边温度以及油腊厚度变化的影响基本相同;不同载荷对油膜温度、进油边温度以     

Thermally-Induced Failures in Railroad Tapered Roller Bearings

An Association of American Railroads (AAR) class F (6 1/2 × 12) tapered-roller bearing assembly is modeled, using finite elements, to examine thermally-induced failures observed in the laboratory when the bearing is operating at relatively high speeds. It is hypothesized that this failure is caused by an unstable thermal expansion/internal bearing load feedback process. Sequentially-coupled, transient thermal and static structural models are used to obtain the thermal-mechanical transient time response as a function of speed, seal type, and lubricant starvation at the rib contact. The model assumes no external loads and zero initial preload (zero end-play). Therefore, the loads developed in the bearing are thermally-induced and self-equilibrated. Two train speeds, viz. 80 and 100 mph, are considered. Simulation results indicate that at axle rotational speeds equivalent to a train speed of 100 mph, a combination of grease starvation and heat flux from the contact seals cause high rib temperature and subsequent unstable load growth which will lead to failure. At rotational speeds equivalent to train speeds of 80 mph or for bearing assemblies that utilize special design seals, the rib temperature is relatively low and no operational instabilities were observed for the model used.     

含有结合面问题的温度场计算

从温度场计算和结合面导热理论入手,提出了结合面在温度场计算中的处理手法,编制了相应的有限元计算程序,并进行了有关计算。对用有限元法较精确地计算含有结合面的温度场问题具有较好的参考作用