Tapered Roller Bearings with Improved Efficiency and High Power Density for Automotive Transmissions

Gradu, Mircea

doi:10.4271/2000-01-1154

Cited by 11 publications

(4 citation statements)

References 1 publication

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“…From the comparison of experimental measurements and predictions from the methods for cylindrical roller bearing which takes the radial load, it is concluded that the Harris model predictions fit well as compared to other two models. Similar analysis and comparison is presented for angular contact ball bearings by Gradu (2000) where it is shown that the Harris model predictions capture the changes in load and speed better than the other two models. However, the prediction and experimental validation for oil drag loss within the screw compressor has not been much reported.…”

Section: Introductionmentioning

confidence: 56%

Experimental validation of the screw compressor oil drag model for various rotor profiles

Abdan

Patil

Stošić

et al. 2023

Proceedings of the Institution of Mechanical Engineers, Part E:

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Injecting oil inside the compressor chambers of the oil-flooded, twin-screw compressors has several advantages. Oil cools the compressing fluid upon mixing with it and hence the compression process is brought nearer to the ideal isothermal compression process. The oil also serves as a lubricant between the meshing rotors and other clearance gaps in the compressor. The thin film of oil formed in the clearance gaps prevents internal leakages too; enhancing the volumetric efficiency of the compressor. Among these desirable effects of injecting oil in screw compressors, there is an undesirable effect too. The interaction (friction) of oil films formed in various clearance gaps with the rotors leads to a drag power loss. Recent studies such as Abdan et al. have proposed more detailed and accurate methods to estimate the oil drag losses in screw compressors. These methods enable the modelling of the effect of even minor changes in rotor profile on the drag loss power. Predictions of this model were hence used to tweak the screw rotor profiles with an objective to reduce the oil drag losses. Such profiles were then retrofitted in the existing machines and tested. Comparing the differences in power consumption of these machines, the component of oil drag loss was deduced. The experimental results show close agreement with the oil drag loss prediction model. The reduction of oil drag losses through profile modifications led to an improvement in the specific power of oil-flooded screw compressor.

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Section: Introductionmentioning

confidence: 56%

Experimental validation of the screw compressor oil drag model for various rotor profiles

Abdan

Patil

Stošić

et al. 2023

Proceedings of the Institution of Mechanical Engineers, Part E:

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“…The friction coefficient of TRBs, which is dependent on the dimensionless film thickness parameter λ, was calculated. They employed experimental data (see Table 1) from Mircea Gradu (2000) [26], which exhibited a good agreement between measured and calculated torque. From 2003-2004, SKF bearing catalogue [15] presented a computational mode incorporating starvation and inlet shear heating effects for calculating rolling frictional moments.…”

Section: State Of the Artmentioning

confidence: 99%

Experimental Analysis of Rolling Torque and Thermal Inlet Shear Heating in Tapered Roller Bearings

et al. 2023

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The investigation in this article focuses on the rolling resistance torque and thermal inlet shear factor in tapered roller bearings (TRBs) through systematic experiments using a modular test setup. TRBs typically operate under Elastohydrodynamic Lubrication (EHL) conditions. At sufficiently high speeds, the majority of rolling friction is due to a significant shift of the pressure centre in the EHL contact. While at lower speeds, sliding friction in the roller-rib contact becomes dominant, which operates under mixed lubrication conditions. Limited literature exists on the impact of inlet shear heating on effective lubricant temperature (Tin_c) and rolling friction in TRBs. To fill this gap, experimental measurements of the total frictional torque under axial loading at different speeds and oil temperatures are performed. With existing models for different friction contributions described in the literature, the rolling resistance due to EHL has been determined for various operating conditions. The effects of dimension-less speed (U), material (G), and load (W) parameters have also been investigated. Under fully flooded conditions, it was observed that the influence of material (G) and load (W) parameters on rolling friction is minor, while the impact of velocity (U) is significant. In the context of rolling resistance, the heating due to shear of the lubricant in the inlet zone plays a significant role. For higher rotational velocities, the estimated rotational torque reduction resulting from inlet shear heating was found to be approximately 6–8%.

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“…Zhou and Hoeprich [27] measured the torque generated at different contacts in a TRB; however, they focused on the losses and not on the dynamics. Gradu [28] also analysed the TRB losses and compared them with equivalent ball bearing. Wrzochal et al [29] presented a new device for measuring the friction torque in rolling-element bearings of different types, where the main goal was to establish a reliable device for quality control measurement.…”

Section: Introductionmentioning

confidence: 99%

The Dynamics of Tapered-roller Bearings – A Bottom-up Validation Study

Razpotnik¹,

Bischof²,

Boltežar³

2023

sv-jme

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Rolling-element bearings are one of the most important elements when predicting the noise of rotating machinery. As a major connecting point between the rotating and non-rotating parts, their dynamic properties have to be accurately known. In this investigation we present a bottom-up approach to characterising the dynamics of the rolling-element bearing. A special test device was designed and built to assess the quality of the well-established analytical modelling approach of Lim and Singh. Two types of bearings were tested, i.e., the ball and tapered-roller types. The dynamic properties were observed by investigating the frequency-response functions. In addition, non-rotating as well as rotating test scenarios were checked. It was shown that the ball bearing model adequately predicts the system’s response, whereas the tapered-roller bearing model requires modifications. These results were further confirmed with a quasi-static load-displacement numerical evaluation, where a full finite-element model serves as the reference.

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Tapered Roller Bearings with Improved Efficiency and High Power Density for Automotive Transmissions

Cited by 11 publications

References 1 publication

Experimental validation of the screw compressor oil drag model for various rotor profiles

Experimental validation of the screw compressor oil drag model for various rotor profiles

Experimental Analysis of Rolling Torque and Thermal Inlet Shear Heating in Tapered Roller Bearings

The Dynamics of Tapered-roller Bearings – A Bottom-up Validation Study

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