Jian Sun, Xin Fang, Jinmei Yao, Zhe Zhang, Renyun Guan and Guangxiang Zhang
The study aims to the distribution rule of lubricating oil film of full ceramic ball bearing and improve its performance and life.
Abstract
Purpose
The study aims to the distribution rule of lubricating oil film of full ceramic ball bearing and improve its performance and life.
Design/methodology/approach
The paper established an analysis model based on the fluid–solid conjugate heat transfer theory for full ceramic ball bearings. The distribution of flow, temperature and pressure field of bearings under variable working conditions is analyzed. Meanwhile, the mathematical model of elastohydrodynamic lubrication (EHL) of full ceramic ball bearings is established. The numerical analysis is used to study the influence of variable working conditions on the lubricant film thickness and pressure distribution of bearings. The temperature rise test of full ceramic ball bearing under oil lubrication was carried out to verify the correctness of simulation results.
Findings
As the speed increased, the oil volume fraction in full ceramic ball bearing decreased and the surface pressure of rolling element increased. The temperature rise of full ceramic ball bearings increases with increasing speed and load. The lubricant film thickness of full ceramic ball bearing is positively correlated with speed and negatively correlated with load. The pressure of lubricating film is positively correlated with speed and load. The test shows that the higher inner ring speed and radial load, the higher the steady-state temperature rise of full ceramic ball bearing. The test results are in high agreement with simulation results.
Originality/value
Based on the fluid–solid conjugate heat transfer theory and combined with Reynolds equation, lubricating oil film thickness formula, viscosity temperature and viscosity pressure formula. The thermal analysis model and EHL mathematical model of ceramic ball bearings are established. The flow field, temperature field and pressure field distribution of the full ceramic ball bearing are determined. And the thickness and pressure distribution of lubricating oil film in the contact area of full ceramic ball bearing were determined.
Peer review
The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-05-2023-0126/
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Jian Sun, Junran Huang, Zhonghao Tian, Jinmei Yao, Yang Zhang and Lu Wang
This paper aims to understand the vibration characteristics of full ceramic ball bearings under grease lubrication, reduce the vibration of the bearings and improve their service…
Abstract
Purpose
This paper aims to understand the vibration characteristics of full ceramic ball bearings under grease lubrication, reduce the vibration of the bearings and improve their service life.
Design/methodology/approach
The Hertz contact stiffness formula for full ceramic ball bearings is constructed; the equivalent comprehensive stiffness calculation model and vibration model of full ceramic ball bearings are established. The dynamic characteristic test of full ceramic ball bearing under grease lubrication was carried out by using the bearing life testing machine, and its vibration was measured, and its vibration acceleration root-mean-square was obtained by software calculation and compared with the simulation results.
Findings
At the rotational speed of 12,000 r/min, the root-mean-square value of vibration acceleration is maximum 10.82 m/s2, and the error is also maximum 7.49%. As the rotational speed increases, the oil film stiffness decreases. In the radial load of 600 N, the vibration acceleration root-mean-square is minimum 6.40 m/s2, but its error is maximum 6.56%. As the radial load increases, the vibration of the bearing decreases and then increases, so under certain conditions increasing the radial load can reduce the bearing vibration. With different types of grease, the best preload is also different; low-speed heavy load should be used when the viscosity of the grease is large, and high-speed light load should be used when the choice of smaller viscosity grease is made.
Originality/value
It provides a theoretical basis for the application of full ceramic ball bearings under grease lubrication, which is of great significance for reducing the vibration of bearings as well as enhancing the service life of bearings.
Peer review
The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-03-2024-0094/
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Jian Sun, Guangxiang Zhang, Zhongxian Xia, Zhigang Bao, Jinmei Yao, Xin Fang, Zhe Zhang and Renyun Guan
To understand the service performance of full ceramic ball bearings under extreme working conditions and improve their service life, dynamic characteristic tests of full ceramic…
Abstract
Purpose
To understand the service performance of full ceramic ball bearings under extreme working conditions and improve their service life, dynamic characteristic tests of full ceramic ball bearings under ultra-low temperature conditions were carried out by a low-temperature bearing life testing machine, and temperature rise and friction were measured under extreme low-temperature environment.
Design/methodology/approach
The heat-flow coupling model of bearing was established by CFD software, and the test results were further analyzed.
Findings
The results show that the temperature rise of the bearing is not obvious in the liquid nitrogen environment. With the increase of the chamber temperature, the lubrication state of the bearing changes, resulting in the temperature rise of the outer ring of the bearing. As the temperature of the test chamber increases, the friction force on the bearing increases first and then decreases under the action of multifactor coupling.
Research limitations/implications
The research results provide test data and theoretical basis for the application of all-ceramic ball bearings in aerospace and other fields and have important significance for improving the service life of high-end equipment under extreme working conditions.
Practical implications
The research results provide test data and theoretical basis for the application of full ceramic ball bearings in aerospace and other fields and have important significance for improving the service life of high-end equipment under extreme working conditions.
Social implications
The research results provide test data and theoretical basis for the application of full ceramic ball bearings in aerospace and other fields and have important significance for improving the service life of high-end equipment under extreme working conditions.
Originality/value
The research results provide test data and theoretical basis for the application of full ceramic ball bearings in aerospace and other fields and have important significance for improving the service life of high-end equipment under extreme working conditions.
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Joshua Prasad, Danielle M. Gardner, Frederick T. Leong, Jinmei Zhang and Christopher D. Nye
This work contributes to the literature on career adaptability by examining the criterion validity of the Cooperation dimension, supporting the inclusion of cooperation into the…
Abstract
Purpose
This work contributes to the literature on career adaptability by examining the criterion validity of the Cooperation dimension, supporting the inclusion of cooperation into the career adaptability construct and informing the nomological network of career adaptability (Nye et al., 2018; Savickas and Porfeli, 2012). The authors also evaluate the improvements in cross-cultural generalizability argued for by Nye et al. (2018) by conducting a criterion validity study of the CAAS including cooperation using a non-Western sample.
Design/methodology/approach
Survey responses from a Chinese adult working sample (N = 208, 53.4% male) were analyzed via relative weights analysis, facilitating the comparison of the Cooperation dimension to other career adaptability dimensions and general adaptability.
Findings
Results demonstrate the added value of the Cooperation dimension across several work outcomes (i.e. work engagement, career commitment, occupational well-being, occupational stress) and highlight Cooperation in predicting interpersonal outcomes (i.e. supervisor and coworker satisfaction).
Originality/value
The inclusion of Cooperation, a dimension originally conceptualized as a career adaptability factor but only recently subjected to additional psychometric evaluation, within the career adaptability paradigm should promote both predictive validity and cross-cultural generalizability.