Analysis of a thrust bearing with a viscoelastic lubricant

The characteristics of a thrust bearing with a viscoelastic lubricant have been analysed. The elasticity of the lubricant, the volume rate of flow of lubricant and the ratio of the inner and outer radii of the bearing are characterized by the parameters α, β and σ. The effects of these parameters on the pressure distribution and the load-bearing capacity have been studied.     

Step slider bearing with viscoelastic lubricant

The performance of an idealized step slider bearing with a viscoelastic lubricant is investigated theoretically. The elasticity of the lubricant is characterized by a dimensionless number α. The effects of the elasticity of the lubricant on the pressure, load-bearing capacity, frictional resistance, coefficient of friction and maximum film thickness were studied in detail and are presented in several graphs and tables.     

Inertia effects in a conical porous bearing with a viscoelastic lubricant

The effects of the inertia and porosity of the bearing material were investigated for conical and squeeze film bearings with a viscoelastic lubricant by the method of averaged inertia. The inertia forces reduce the loadbearing capacity. The porosity of the material decreases the pressure and the load capacity. The effect of the elasticity of the lubricant is to increase the pressure and the load-bearing capacity at any point. The effects of the characteristics of the bearing on the pressure and the load-bearing capacity are presented graphically.     

Normal vibration of a plain bearing working under boundary lubrication conditions

During sliding in a plain-bearing system under boundary lubrication conditions, the impact of the existing microasperities causes the system to vibrate. The resulting spectrum depends, among other things, on the type of material and the micro- and macrogeometries of the sliding surfaces. Running-in of plain bearings can be monitored by studying the changes in the respective spectra of vibrations     

Dynamic stability experiments of compliant foil thrust bearing with viscoelastic support

In order to reduce the complexity of machine construction and improve the mechanical efficiency, high speed rotation machineries usually implement self-acting gas bearings to substitute the traditional oil-lubricated bearings. This paper presents test results of a gas thrust bearing with viscoelastic support which is designed for high speed turbo-machinery. The gas bearing, which belongs to compliant foil bearings, consists of a top thin metal foil and a bottom thin rubber foil. Static and stability experiments are conducted on a high speed gas turbine test rig. The static results indicate that the structural stiffness of test bearing generally increases with the increase in axial load and the decrease in thickness of bottom foil. In the rotation tests, rotor runs stably with small vibration amplitude, which is dominant in waterfall plot during whole speed up procedure. It shows that test bearing has preferable stability characteristics for high speed gas turbines.     

Design of an offset hydrostatic thrust bearing under dynamic loading conditions

An offset hydrostatic thrust bearing is analysed to determine the effect of vibration of the rotating plate on the performance characteristics. The flow developed is asymmetric because the surface rotation axis is offset from the bearing axis. The governing Reynolds equation is solved using semianalytical methods. The average load capacity, frictional force and lubricant flow rate are strong functions of the bearing offset L, bearing number λ, film thickness profile H, film thickness variation ? and the ratio between the frequency of vibration of the rotating plate and the angular speed of rotation.     

Performance analysis of a fully textured hybrid circular thrust pad bearing system operating with non-Newtonian lubricant

The present paper deals with the theoretical investigation of the influence of dimple geometry on fully textured hybrid thrust pad bearing and operating with non-Newtonian lubricant. The modified Reynolds equation which governs the flow of non-Newtonian lubricant in the clearance space has been solved using Finite Element Method. The simulated results indicate that the values of load carrying capacity, frictional power loss, maximum pressure and fluid film stiffness coefficient are significantly affected by the behavior of lubricant. The results presented in the study are expected to aid in determining the optimum value of dimple diameter and depth for the optimum bearing performance.     

袋式阶梯瓦气体止推轴承的分析计算

利用有限元法求解可压缩流体雷诺方程，计算了袋式阶梯瓦气体止推轴承的工作性能，分析了不同结构参数对轴承承载能力的影响，通过计算实例说明，该种轴承具有与螺旋槽气体止推轴承接近的较高承载能力，值得推广应用。     

Study of thermal boundary conditions for a plain journal bearing

Three-dimensional energy and heat conduction equations for fluid and bush temperatures and a one-dimensional equation for journal temperature have been solved. Two alternative boundary conditions at the inlet have been examined. Heat transfer from bush to oil in supply groove is considered. A more appropriate boundary condition is identified.     

Thrust bearing using a magnetic fluid lubricant under magnetic fields

This paper describes a thrust bearing using a magnetic fluid lubricant under a magnetic field. The critical pressures of the bearing versus the magnitude of the magnetic flux densities have been investigated experimentally. It is shown that the critical pressures of the proposed bearing are larger than those of the normal lubricated bearing under high speeds.     

Lubrication of hydroelectric turbine thrust bearings with a diester-based synthetic lubricant

A diester-based lubricant was found to reduce friction substantially in the thrust bearings of a hydroelectric turbine, compared with a conventional petroleum oil. Bearing temperatures were immediately reduced by 10–11 °C and bearing failures were eliminated. Revenue savings estimated at $10,000,000 per year have been made due to an increase in power production, and the elimination of repair work and downtime costs.¹     

推力圆柱滚子轴承预紧力的测量和计算

数控立车工作台底部推力圆柱滚子轴承的预紧力是通过压缩碟簧获得的,但结构空间狭小,无法直接测量。通过测量齿轮匀速转动时圆周某点处的切向拉力来间接测量轴承预紧力,并通过调整垫调整碟簧压力获得要求的预紧力。     

Model of wear in a plain bearing under boundary lubrication

Wear in a plain bearing under boundary lubrication is described by three groups of related dimensionless numbers obtained from dimensional analysis. Experimental results verify the proposed model to a high degree of correlation     

The effect of lubricant inertia in externally pressurized bearings using a viscoelastic lubricant

The inertia effects in an externally pressurized bearing with a viscoelastic lubricant were considered using the methods of averaged inertia and of iteration. The inertia forces reduce the load-bearing capacity at a given flow rate. The effect of the elasticity of the liquid is to increase the pressure and the load-bearing capacity at any point. The effects of the elastic number S, the volume flow rate Q, the ratio σ of the inner radius of the bearing to the outer radius of the bearing and $\text{H =}\text{h}\text{a}$ on the pressure and the loadbearing capacity are presented graphically. The results obtained by the two methods are in good agreement.     

Hydrodynamics of a radial bearing with electrically conducting gas lubricant

The proposed method permits self-similar hydrodynamic calculation of a radial bearing with electrically conducting gas lubricant. The method takes account of the magnetic field.     

Comparison of an optimum‐profile hydrodynamic thrust bearing with a typical tilting‐pad thrust bearing

The oil gap profile in a hydrodynamic thrust bearing exerts a great influence on the bearing properties, and hence the optimisation of the oil gap profile is one method for improving the bearing properties. In the present work, the properties of two hydrodynamic thrust bearings have been experimentally compared under realistic load/ speed conditions. One was a typical tilting‐pad bearing and the other was an unconventional bearing with an elastic thrust plate. The latter was designed using oil gap profile optimisation and design parameter selection. Owing to the design method used, the oil gap profile was close to optimum for the assumed load/speed conditions. The results show a substantial increase in the minimum oil film thickness and lower temperature in the bearing with the elastic thrust plate. This improvement of properties is thought to be because of the optimised oil gap profile in the bearing.     

Metallic sliding friction under boundary lubricated conditions: Investigation of the influence of lubricant at the start of sliding

Experiments are described in which a hard half-wedge, representing a scaled up model asperity, was indented into the horizontal surface of a relatively soft specimen with the specimen then moved in a direction parallel to its surface and normal to the wedge edge. Forces measured at the wedge-specimen interface are used to investigate the state of lubrication at the interface at all stages of the experiment, i.e. from initial indentation to final steady-state wave formation. The results are used to offer possible explanations for the nature of boundary lubrication and of stick-slip motion.     

Calculation of friction for indenter with fractal roughness that slides against a viscoelastic foundation: Improved model

Additional results on calculating the deformation force of friction for a rough indenter sliding on a viscoelastic foundation are presented. The results consider the influence of the roughness on the normal contact load. As in earlier studies, the deformation properties of a foundation are described by the Kelvin model and the roughness of an indenter is represented by the Cantor–Borodich fractal, which consists of a set of rectangular asperities.     

Design of annular recess hydrostatic thrust bearing under dynamic loading

Design charts are presented of a dynamically loaded thrust bearing with as annular recess. The effect of non-parallelism between the bearing and the runner surfaces is also considered, since this is a common problem in hydrostatic thrust bearings. Based on pre-assigned dynamic excitations the pressure equation is solved numerically by finite difference methods to render the bearing performance characteristics namely: load capacity; bearing stiffness; damping coefficient; and lubricant flow rate. Results concluded that the bearing performance chareacteristics are dependent on the bearing radii ratios, the squeeze number, the bearing number and the tilt parameter.     

Studying microprofile of surface of steel disc that operates in various friction units in a pair with MK-5 metal-ceramic frictional material

Results of studying the roughness of the working surface of a steel disk that operates in a pair with a copper-based metal-ceramic frictional layer under film lubrication are presented. The dependence of the root-mean-square roughness on the duration of operation in the steady wear mode is obtained. The microstructure of the 65G steel is identified at various values of the hardness and the dependence of the ultimate strength on the hardness is obtained. Recommendations on selecting rough surfaces and mechanical characteristics of the 65G steel for operation in a pair with the MK-5 metal-ceramic material are given.