Advanced Distortion Analysis of Heat Treated Rings*

The basic approach to interpret distortion as a system property is accepted in science and industry. The determination of significant factors and interactions on distortion in the overall production process of selected components represents a central point to identify relevant distortion mechanisms. In this context, a component specific distortion description is a major step to answer distortion problems. In the field of ball bearing engineering, roundness deviation of raceways is an important characteristic. But this parameter is not useful for distortion engineering because no information concerning ring shape is given. But in literature, roundness deviation can be separated in its respective forms like oval and triangle shape with harmonic analysis. In addition, this analysis can be used to specify an amplitude and a direction in the different shapes to describe distortion. In this article, harmonic analysis is used for advanced distortion analysis of tapered roller bearing. An analysis in graphical form is introduced, which illustrates both the amount and the direction of distortion.

Design of logarithmic crowned roller for tapered roller bearings based on the elastohydrodynamic lubrication model

Purpose The purpose of this paper is to study the film-forming capacity of logarithmic crowned roller for tapered roller bearing (TRB) and to design a tapered roller profile based on an elastohydrodynamic lubrication model. Design/methodology/approach A coupled model, incorporating a quasi-static model of TRBs and an elastohydrodynamic lubrication model was developed to investigate the load distribution of TRB and to evaluate the lubrication state of tapered roller/raceway contact. Findings The model is verified with published literature results. Parametric analysis is conducted to investigate the effect of crown drop on azimuthal load distribution of the roller, film thickness and pressure distribution in the contact area. The result shows that crown drop has little influence on the azimuthal load distribution; also, the film thickness and the pressure distribution are asymmetric. When the tapered roller is designed and manufactured, the crown drop of the small end should be larger than that in the large end. Originality/value Precise roller profile design is conducive to improve the fatigue life of TRBs. Currently, most crown design methods neglect the influence of lubrication, which can lead to a non-suitable roller profile. Therefore, the present work is undertaken to optimize roller profiles based on lubrication theory.

Comparative study of a simulative bearing design with an experimentally determined data of a prototype bearing

In some specific applications, the need of an optimized rolling bearing, having a similar load carrying capacity as a tapered roller bearing but with much lower friction losses is still to be addressed. In this paper, a new model is developed using a multibody simulation software and its experimental validation is presented.After studying many different (in use and only patented) roller geometries and based on an existing and already validated model for tapered roller bearings, a new model has been created changing the basis of its geometry. When the rolling bearing is highly loaded, the new geometry will show lower friction losses than a conventional tapered roller bearing. In order to confirm this premise, as well as to validate the model, a prototype of the new optimized geometry has been manufactured and experimentally tested, together with a tapered roller bearing of same main dimensions. The tests have taken place in a frictional torque test rig, where it is possible to realistically reproduce the loads and misalignments occurring on a bearing.The results of these tests together with its comparisons with the results of the multibody simulation models are discussed here. It has been observed, that the new model not only can be validated, but also presents less friction losses than the ones obtained when using a tapered roller bearing under some operating points with highly loaded bearings.

Research on coupled vibrations of driveshaft–rear axle system based on nonlinear hybrid model

The transmission shaft–rear axle system is consisted of universal joint, hypoid gear pair, tapered roller bearing, and half shaft. In this article, as a combination of system dynamics and structure dynamics, a hybrid dynamic model of the bending–torsional–shaft vibration of the driveshaft main reducer was established to study its noise vibration harshness performance. Through dynamic frequency sweep analysis, it is found that the natural frequency of torsional vibration of the system is 53.96 Hz. Getting the natural frequency of the torsional vibration of the systems being 57 Hz by the bench tests and Adams simulations. The correctness of the nonlinear hybrid model of the driveshaft–rear axle system is proved. This research will be beneficial to the design, monitoring, and fault detection of the automobile transmission system.

Defect detection in freight railcar tapered-roller bearings using vibration techniques

Currently, there are two types of defect detection systems used to monitor the health of freight railcar bearings in service: wayside hot-box detection systems and trackside acoustic detection systems. These systems have proven to be inefficient in accurately determining bearing health, especially in the early stages of defect development. To that end, a prototype onboard bearing condition monitoring system has been developed and validated through extensive laboratory testing and a designated field test in 2015 at the Transportation Technology Center, Inc. in Pueblo, CO. The devised system can accurately and reliably characterize the health of bearings based on developed vibration thresholds and can identify defective tapered-roller bearing components with defect areas smaller than 12.9 cm2 while in service.

Study on Radial Stiffness of Contact Pair of Logarithmic Modified Tapered Roller Bearing

Based on Hertz elastic contact theory, elastohydrodynamic lubrication theory, the equivalent radial stiffness model of roller raceway contact pair of logarithmic modified tapered roller bearing is derived under the consideration of oil film stiffness. The calculation results show that the equivalent radial contact stiffness increases with the increase of contact load, increases linearly with the increase of effective contact length of roller, and changes little with the increase of modification f1. When the radial load is small, the oil film has a great influence on the equivalent radial stiffness, which decreases gradually with the increase of the radial load.