On the dynamics of a lubricated roller contact

Li, S.; Kolivand, A.

doi:10.1016/j.mechmachtheory.2020.103959

“…The present defect had half the hight and 25 times the longitudinal extension in the rolling direction compared to the smallest defect studied by Li and Kolivand. Since the smallest defect was barely noticeable in the reference [23] and the present line defect was 50 times smoother, it was judged as acceptable. The resulting vibrations in the twin-disc machine used in step 6 was monitored and found to be within the allowable range for experiment.…”

Section: Methodsmentioning

confidence: 91%

“…7 presents a longitudinal profile across the initial contact pile-up for a disc that had been subjected to an imprint force F = 10 kN. The presence of such line defect could, if too large, introduce vibrations during the subsequent RCF experiment, which in turn may affect RCF life as illustrated by Li and Kolivand [23] . The present defect had half the hight and 25 times the longitudinal extension in the rolling direction compared to the smallest defect studied by Li and Kolivand.…”

Section: Methodsmentioning

confidence: 99%

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An imprint method to produce surface asperities for EHL and RCF experiments

Everitt

¹

,

Alfredsson

²

,

Öberg

³

2021

MethodsX

0

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A method was developed for creating single well-defined surface asperities using an imprint technique. The proposed method enables: Creation of well-defined micrometre high asperities Creation of asperities which survived more than 35 million EHL contact cycles Damage tracing thanks to the possibility to control the damage initiation sites. The technique is based on rolling a hard disc with indents against a soft disc for creating single surface asperities. The contact pressure causes plastic deformation forcing material into the indents to create the asperities. The height of the asperities can be controlled by adjusting the applied force. After initial reshaping during the run-in process, the asperities were strong enough to survive more than 35 million elastohydrodynamic lubrication cycles, which should be of great interest for the researchers who investigate rolling contact fatigue experimentally. The method could also aid the research on the run-in process by enabling tracing the development of specific surface defects. Since the method can produce high and strong asperities it might also prove useful for investigations how asperities deform under sever contact conditions.

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“…In a study by Morales-Espejel et al [13], the contact sliding speed, pressure and specific film thickness influenced the final damage level of micro-pitting based on a stable lubrication condition. However, a remarkable study by Li et al [14] revealed the dynamic relationship between contact stress and lubrication conditions, suggesting a dynamic model for micro-pitting. The effects of microscale surface irregularities on micro-pitting were also discussed by Moorthy et al [15].…”

Section: Introductionmentioning

confidence: 99%

A Novel Tooth Tip Relief Method for Reducing Micro-Pitting of Spur Gears

Xu

¹

,

Liang

²

,

Zuo

³

et al. 2021

Preprint

1

0

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Micro-pitting is a common fatigue failure mode of spur gears. To reduce it, this paper proposes a novel tooth tip relief method. Gear meshing simulation is firstly performed considering the actual contact path, showing that there are four Hertz contact stress peaks in the transition areas of the tooth flank. Equations are then developed for the novel tooth tip relief method: one focuses on the smooth transition between the involute profile and the tip relief region, the other on the smooth transition between the tip relief region and the tooth tip. The results of curvature radius and Hertz contact stress show that the proposed novel method can effectively reduce the Hertz contact stress peaks, which indicates this tip relief method could benefit for reducing the micro-pitting. Finally, both wear simulations and bench tests are conducted, verifying the effectiveness of the proposed method for reducing the micro-pitting of spur gears.

show abstract

“…In a study by Morales-Espejel et al, 13 the contact sliding speed, pressure, and specific film thickness influenced the final damage level of micro-pitting based on a stable lubrication condition. However, a remarkable study by Li and Kolivand 14 revealed the dynamic relationship between contact stress and lubrication conditions, suggesting a dynamic model for micro-pitting. The effects of microscale surface irregularities on micro-pitting were also discussed by Moorthy and Shaw.…”

Section: Introductionmentioning

confidence: 99%

A novel tooth tip relief method for reducing micro-pitting of spur gears

Xu

¹

,

Liang

²

,

Zuo

³

et al. 2021

Advances in Mechanical Engineering

3

0

View full text Add to dashboard Cite

Micro-pitting is a common fatigue failure mode of spur gears. To reduce it, this paper proposes a novel tooth tip relief method. Gear meshing simulation is firstly performed considering the actual contact path, showing that there are four Hertz contact stress peaks in the transition areas of the tooth flank. Equations are then developed for the novel tooth tip relief method: one focuses on the smooth transition between the involute profile and the tip relief region, the other on the smooth transition between the tip relief region and the tooth tip. The results of curvature radius and Hertz contact stress show that the proposed novel method can effectively reduce the Hertz contact stress peaks, which indicates this tip relief method could benefit for reducing the micro-pitting. Finally, both wear simulations and bench tests are conducted, verifying the effectiveness of the proposed method for reducing the micro-pitting of spur gears.

show abstract

On the dynamics of a lubricated roller contact

Cited by 12 publications

References 33 publications

An imprint method to produce surface asperities for EHL and RCF experiments

An imprint method to produce surface asperities for EHL and RCF experiments

A Novel Tooth Tip Relief Method for Reducing Micro-Pitting of Spur Gears

A novel tooth tip relief method for reducing micro-pitting of spur gears

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