机床主轴轴承摩擦生热特性分析

为研究圆柱滚子轴承摩擦生热特性,构建了一种考虑了主轴-轴承装配过盈量、离心力以及配合表面粗糙度的拟静力学分析模型.应用局部法计算得到轴承各部件间的摩擦生热量,通过实例分析了不同工况条件以及润滑参数对摩擦生热的影响.结果表明,轴承转速及外载荷对摩擦生热量有较大影响,转速越高,摩擦生热量增长越明显;润滑油动力黏度或油气比例...     

基于局部热源法的滚子轴承温度场分布的研究

针对圆柱滚子轴承的结构和特点,分析了圆柱滚子轴承的生热机理,基于局部热源法建立了滚子轴承各部分的功率损耗计算模型;在ANSYS软件中采用APDL语言建立了滚子轴承温度场分析的有限元模型,确定了有限元模型的对流边界条件,分析了不同工况下滚子轴承生热特性和温度场分布规律。结果表明:中低速时总体法和局部热源法计算得到的摩擦功耗结果吻合较好,高转速时总体法计算得到的结果明显低于局部热源法计算得到的结果;内圈转速、径向载荷和润滑油的粘度对轴承的生热量和温升均有显著影响。     

径向载荷作用下高速交叉滚子轴承的载荷分布

对径向载荷作用下的高速交叉滚子轴承进行了受力分析,建立了考虑离心力的滚子载荷方程,用Matlab分析了转速、径向外载荷、游隙对交叉滚子轴承载荷分布的影响,为高速交叉滚子轴承的结构优化设计中参数的确定提供了依据。     

高速圆柱滚子轴承非线性刚度分析

在航空发动机高速圆柱滚子轴承拟静力学分析基础上，建立基于轴承径向游隙的高速圆柱滚子轴承非线性刚度计算模型，分析了轴承内、外圈转速对高速圆柱滚子轴承工作径向游隙影响的关系，并对高速圆柱滚子轴承非线性刚度特性进行了研究，最后就某型号航空发动机主轴高速圆柱滚子轴承进行了实例计算与分析，得出在满足主机支承刚度条件下的合理高速圆柱滚子轴承工作径向游隙使用范围。     

陀螺电机轴连轴承生热分析

基于摩擦学理论,对轴连轴承组件生热进行了研究.针对轴连轴承组件的具体工况及结构特点,分析了轴连轴承组件的发热机理,建立了轴承组件内各部分功率损失计算模型,在此基础上得出了轴承总的生热和轴承各单元间的局部生热.以某型陀螺电机轴连轴承为例分析了不同工作转速和工作载荷对轴承总生热和各单元局部生热的影响.结果表明,轴承转速、轴...     

加速工况下高速圆柱滚子轴承打滑分析

针对高速轻载圆柱滚子轴承打滑问题,在考虑轴承涡动、径向游隙变化和内圈加速工况基础上,建立了高速轻载圆柱滚子轴承运动学和动力学模型,研究了有无涡动、不同径向载荷、内圈加速度和径向游隙等因素对圆柱滚子轴承打滑特性的影响。研究结果表明:在轴承加速过程中,保持架转速、打滑率和油膜厚度均随时间呈上升趋势,但当涡动存在时会使保持架转速、打滑率和油膜厚度在上升过程中出现抖动;增大径向载荷和径向游隙有利于减小保持架的打滑率。     

圆柱滚子轴承的动载荷分布

通过虚滚子的假设,采用静不定方法研究了圆柱滚子轴承在径向载荷作用下的动载荷分布,得出圆柱滚子轴承各滚子的动载荷随轴承的转动周期性变化,及径向载荷的大小、游隙、转速和滚子个数等与圆柱滚子轴承动载荷分布的关系。     

滚子偏斜工况下的圆柱滚子轴承弹流润滑分析

以存在滚子偏斜工况的圆柱滚子轴承为研究对象,基于轴承拟静力学模型与有限长线接触弹流润滑模型建立圆柱滚子轴承弹流润滑理论计算模型,并基于力学特性分析工况参数对圆柱滚子轴承滚子与滚道接触区域润滑性能的影响,结果表明：力矩载荷作用后,油膜压力与油膜厚度呈非对称分布;力矩载荷越大,油膜压力和油膜厚度的偏斜程度越明显,易导致轴承润滑性能恶化;径向载荷和内圈转速越大,油膜压力偏斜程度越小。     

高速角接触球轴承油气润滑温升特性研究

油气润滑系统广泛应用于高速滚动轴承,油气润滑条件下轴承温升特性与温度场分布是影响轴承极限转速与动态工作稳定性的重要因素.基于高速滚动轴承摩擦学与两相流理论,以角接触球轴承为研究对象,建立了油气润滑条件下轴承与流体域之间的流固耦合模型.利用流体仿真软件Fluent对油气润滑条件下高速角接触球轴承与流体之间的传热方式及温度场分布进行了数值模拟分析,得到了轴承与轴承腔体的温度场分布.并进一步研究了供油量、润滑油粘度、轴承转速和载荷对轴承温升的影响,得到了油气润滑参数等与轴承温度场热平衡之间的关系.结果 表明:轴承转速与径向载荷是影响高速滚动轴承生热量与温升的主要因素,轴承内部温度场分布不均匀,对于特定工况存在最佳供油量与润滑油黏度使轴承温升最小.     

弹流润滑状态下机床主轴轴承刚度特性分析

圆柱滚子轴承的刚度特性会对机床动态性能产生较大影响.在双列圆柱滚子轴承力学分析的基础上,综合赫兹接触与润滑油膜对轴承刚度的影响,分析了不同工况以及润滑参数下的轴承刚度变化特性.分析结果表明,弹流润滑产生的润滑油膜会使轴承综合刚度下降;随着外载荷的增大,赫兹刚度与油膜刚度均有所提升,轴承综合刚度提高;提升轴承预紧量有利于...     

Rolling Element Skew in Tapered Roller Bearings

This paper reports on the roller skew in tapered roller bearings monitored by contact potential difference probes. The effect of the load, rotational speed, and viscosity of lubricant on roller skew angle, along with the variation of bearing torque with the running conditions, were measured on a LM501300 bearing. Two greases (SHC15 and SHC460) were used to lubricate the bearing. The skew angles were found to vary from 0.15° to 0.6°. The results indicate that the skew angle depends on the friction force at the roller-rib interface. An empirical equation is derived which relates the skew angle to the bearing operational parameters.     

The Prediction of Contact Pressure–Induced Film Thickness Decay in Starved Lubricated Rolling Bearings

Under starved conditions the thickness and distribution of the lubricant film in an elastohydrodynamically lubricated (EHL) contact is directly related to the distribution of lubricant on the track in the inlet to the contact. In starved lubricated rolling bearings this lubricant distribution is determined by many effects. The authors have developed a model to predict the oil lost from the track induced by EHL pressure with no replenishment. A complete bearing is modeled with multiple rolling element EHL contacts and with the applied load to the rolling elements varying along the circumference of the bearing. Results of the oil layer thickness on the track are presented for a ball bearing and a spherical roller bearing for different bearing loads and rotational speeds. The predicted layer thickness decay rate for a ball bearing is significantly larger than for a spherical roller bearing and the predicted effect of the bearing load on the decay rate is small compared to the effect of the rotational speed. The predicted decay periods due to the contact pressure effect are small compared to the observed (grease) life of bearings. The results show that a bearing cannot sustain an adequate layer of oil on the running track unless significant replenishment takes place.     

Variable-viscosity effects in externally pressurized spherical oil bearings

Externally pressurized spherical bearings were analysed considering the rotational inertia of the lubricant and the variation of the lubricant viscosity along the flow. The equations of motion expressed in spherical coordinates were suitably reduced to describe the lubricant flow through the bearing clearance. A numerical solution of the resulting equations, in which the variation of viscosity with temperature was considered, was obtained using the finite-difference technique. The effects of bearing geometry, bearing speed, inlet oil temperature, bearing load, lubricant flow rate and frictional torque on pressure and temperature distributions under adiabatic flow conditions were investigated. Satisfactory agreement between experiment and the adiabatic solution was found for a high speed factor. The theory is applicable to both fitted and clearance-type spherical bearings.     

角接触球轴承的温度场分析

研究轴承的发热、传热过程,可为轴承动态油膜的热失稳研究提供理论支持。建立滚动轴承油气或油雾润滑下的热节点传热模型,利用热网络法建立温度场计算模型,并考虑轴承转速、载荷、离心力和自旋对温升的影响,计算出各节点的温度。结果表明,角接触球轴承的热生成与轴承转速、载荷、离心力和自旋有关,转速越高,载荷越大,则轴承的温升越高;随着转速增大,离心力和自旋对温升的影响增大,尤其高速情况下,离心力和自旋对轴承温升的影响不可忽略。     

基于热-应力耦合的高速圆柱滚子轴承凸度值分析

考虑到圆柱滚子轴承在运转过程中温升对轴承性能的影响,基于滚动轴承动力学理论、摩擦学原理和热分析理论,利用ANSYS建立了圆柱滚子轴承热-应力耦合有限元分析模型,分析了对数修形滚子的凸度值对轴承温升和接触应力的影响以及径向载荷和转速对最优凸度值的影响。结果表明:滚子最高温度随凸度值增大而增大,最大接触应力随凸度值的增大先减小后增大;考虑耦合时轴承零件的接触应力大于未考虑耦合时的接触应力;考虑耦合时滚子最优凸度值随径向载荷和转速的增大而增大,未考虑耦合时滚子最优凸度值随径向载荷增大而增大,但不随转速增大而变化。     

Effect of lubricant viscosity grade on mechanical vibration of roller bearings

This work aims to characterize vibration behavior of roller bearings as a function of lubricant viscosity. Experimental tests were performed in NU205 roller bearings, lubricated with mineral oil of three different viscosity grades (ISO 10, 32 and 68). The mechanical vibration was determined through the processing and analysis of bearing radial vibration data, obtained from each of the lubrication conditions, during 2 h of test run for temperature stabilization and under several bearing shaft speeds. The applied radial load was 10% of the bearing nominal load. Through root mean square (RMS) analysis of the vibration signals, it was possible to identify specific frequency bands modulated by the change in lubricant viscosity, which was related to change in oil film thickness.     

圆柱滚子轴承弹流接触副刚度及阻尼系数研究

针对圆柱滚子轴承中滚子-滚道弹流接触副,建立有限长线接触非稳态弹流润滑模型,利用追赶法、快速傅里叶变换和Newmark技术数值求解接触副在自由振动下的衰减曲线。以刚体接近距离的变化作为判断接触副振动的标准,结合弹流润滑模型和有阻尼系统的自由振动模型,给出预测滚子-滚道弹流接触副动力学参数的方法,考察初始扰动量、润滑剂黏压系数、滚子长度和载荷对刚度和阻尼系数的影响。结果表明：小扰动下,初始扰动量大小对刚度和阻尼系数的影响可忽略不计;弹流润滑下的刚度小于干接触下的Hertz接触刚度;增加润滑剂黏压系数、滚子长径比和载荷,均可增大弹流接触副的刚度系数;阻尼系数随润滑剂黏压系数的增加而减小,随滚子长径比的增加而增加,随一定范围内载荷的增加而减小。     

An experimental investigation of wear and fatigue life reduction of boundary lubricated spherical roller thrust bearings

Wear and fatigue life reduction in boundary lubricated spherical roller thrust bearings has been investigated. Previously presented results from measurements show that there is a significant change in the washer profile due to wear. This change in surface profile greatly affects the fatigue-life of the bearings. A fractional factor experiment series was used to study how the contacting surfaces of the bearing were affected by the rotational speed, load, hardness of the contacting surfaces and type of oil. The results show that the fatigue life and amount of wear on the washer surfaces were affected by the type of lubricant and rotational speed. A change of the load or a change of the hardness of the contacting surfaces did not influence the wear or the fatigue life of the contacting surfaces.     

基于Fluent的轴承腔温度场仿真分析

油气润滑中,轴承转速和空气流量对轴承的工作温度有着重要影响。根据基本润滑原理,推导并计算了深沟球轴承在不同转速和空气流量下的发热量,运用Fluent软件对深沟球轴承的温度场和流场进行仿真计算。根据仿真结果分析,得到了不同转速情况下轴承腔的最高工作温度,并分析了轴承腔空气入口速度和润滑油粘度对轴承内部对流换热系数的影响。     

A study on the sound of roller bearings operating under radial load

The purpose of the paper is to numerically investigate the sound characteristics of roller bearings operating under radial load. For the sake of simplifying the analysis, it was assumed that the roller bearings are infinitely long, a noise source due to pressure fluctuation of oil film is taken as a line noise source, and acoustic energy losses in the bearing are neglected. To obtain sound characteristics of the bearing, the rolling contact load and the sound pressure level distributions were calculated for various operating conditions, and the results were compared with each other. How much the bearing noise can be affected by the design parameters, such as radial clearance of the bearing, viscosity of lubricant, and the number of rollers was also investigated. The results and discussions of the present paper could aid in the design of low-noise roller bearings and to solve the noise problems related to such bearings.