Mixed Lubrication and Surface Topography of Rolling Contacts

1974 ◽  
Vol 188 (1) ◽  
pp. 461-469 ◽  
Author(s):  
R. H. Leaver ◽  
R. S. Sayles ◽  
T. R. Thomas

Measurements of friction torque in a tapered roller bearing are made over a range of axial loads at low rotational speeds. Under these conditions considerable metallic contact between surface asperities occurs. Experimental and theoretical values of no-contact time are compared. The usually adopted ratio of calculated film thickness to gross surface r.m.s. value is shown to be a less meaningful measure of the quality of lubrication than one based on the r.m.s. after filtering out contributions due to asperities of wavelength greater than twice the Hertzian width. An analysis of the statistical properties of worn and unworn surfaces is made. Digital filtering of the power spectrum reveals differences that are not apparent in the unfiltered data. Asperities of long and very short wavelengths, compared with the Hertzian width, are shown to be little affected during running-in whilst those of intermediate size are removed.

1976 ◽  
Vol 98 (4) ◽  
pp. 564-572 ◽  
Author(s):  
J. Y. Liu

This paper presents an analytical study of the load distribution in a tapered roller bearing operating at a high speed and under combined loading. The friction forces at the rolling contacts and the cage forces are not considered. A numerical example showing, among other things, the effects of misalignment and speed on the bearing fatigue life and the sliding velocity at the flange contact is given.


1996 ◽  
Vol 118 (1) ◽  
pp. 257-263 ◽  
Author(s):  
H. Zantopulos

Equations and their derivations for finding the radial and axial stiffnesses of a single-row tapered roller bearing, assuming a rigid shaft and housing, are given for any case of combined radial and axial loads. This method is extended to include the two-row bearing under certain conditions. Also presented are tables to facilitate these calculations.


2004 ◽  
Author(s):  
Hiroki Matsuyama ◽  
Hirofumi Dodoro ◽  
Kiyoshi Ogino ◽  
Hiroyuki Ohshima ◽  
Kazutoshi Toda

Author(s):  
Constantine M. Tarawneh ◽  
Arturo A. Fuentes ◽  
Brent M. Wilson ◽  
Kevin D. Cole ◽  
Lariza Navarro

Catastrophic bearing failure is a major concern for the railroad industry because it can lead to costly train stoppages and even derailments. Excessive heat buildup within the bearing is one of the main factors that can warn of impending failure. A question is often raised regarding the transfer of heat from a wheel during braking and whether this can lead to false setouts. Therefore, this work was motivated by the need to understand and quantify the heat transfer paths to the tapered roller bearing within the railroad wheel assembly when wheel heating occurs. A series of experiments and finite element (FE) analyses were conducted in order to identify the different heat transfer mechanisms, with emphasis on radiation. The experimental setup consisted of a train axle with two wheels and bearings pressed onto their respective journals. One of the wheels was heated using an electric tape placed around the outside of the rim. A total of 32 thermocouples scattered throughout the heated wheel, the axle, and the bearing circumference measured the temperature distribution within the assembly. In order to quantify the heat radiated to the bearing, a second set of experiments was developed; these included, in addition to the axle and the wheel pair, a parabolic reflector that blocked body-to-body radiation to the bearing. The appropriate boundary conditions including ambient temperature, emissivity, and convection coefficient estimates were measured or calculated from the aforementioned experiments. The FE thermal analysis of the wheel assembly was performed using the ALGOR™ software. Experimental temperature data along the radius of the heated wheel, the bearing circumference, and at selected locations on the axle were compared to the results of the FE model to verify its accuracy. The results indicate that the effect of thermal radiation from a hot wheel on the cup temperature of the adjacent bearing is minimal when the wheel tread temperature is at 135°C (275°F), and does not exceed 17°C (31°F) when the wheel tread is at 315°C (600°F).


2019 ◽  
Vol 71 (1) ◽  
pp. 61-73 ◽  
Author(s):  
Ayush Jain ◽  
Abhishek Singh ◽  
Arendra Pal Singh

Purpose This paper aims to study the sliding wear and coefficient of friction (COF) using “ball on disc” tribometer. Discs of bearing steel were subjected to different tribological parameters such as heat treatment (through hardening and case hardening), sliding speed, sliding distance and micro-geometry of the functional ball and disc point contact. Results obtained from tribometer were correlated with the preload loss in tapered roller bearing. Preload loss is subjected to wear rate pattern with respect to the internal geometry and micro-geometry of functional surfaces of the tapered roller bearing, caused by internal resistance between roller large ends sliding against cone supporting face. This confirms the optimum geometry and physical/mechanical property of the tapered roller bearing, which makes the use of these bearings under the demanding application in the automotive industry such as differential gears and installation of pinions of differential gears in power transmissions or wheels. Design/methodology/approach The paper opted for an exploratory study using the design of experiments with full factorial method. The approach was to do ball on disc sliding wear test and correlate that sliding wear with preload loss in tapered roller bearing. Findings The paper provides the limit of preload loss in tapered roller bearing. Research limitations/implications Because of the chosen research approach, the research lacks the effect of environmental conditions such as temperature and relative humidity and lube film thickness effect on wear test. It also lacks the validation part with actual preload loss on tapered roller bearings. Above work is included in future scope of work. Practical implications This paper includes the recommendation for surface parameters which can increase the bearing life by reducing the preload loss in tapered roller bearing. Social implications This paper includes the recommendation for surface parameters for bearing manufacturing industries. Originality/value This paper provides the relation between sliding wear and preload loss in tapered roller bearing.


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