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Proposing a new type of water-lubricated thrust bearing meets the load-bearing requirements of high-power shaft-less rim driven thrusters.

The designs were tested by establishing a bearing thermal-fluid-magnetic comprehensive simulation model and developing bearing fluid film force and magnetic simulation. Lubrication performance tests were carried out on the bearing test rig.

The Halbach array of magnet blocks is able to reach the maximum magnetic force. The material of sheath can help increase the magnetism. The magnetism is able to reduce wear during low-speed and the start-stop phase, while the eddy current loss at high speeds will lead to a decrease in magnetic force. The experiment found that the bearing was more stable at low speeds and would not demagnetize due to the temperature rise, but it is necessary to pay attention to the running stability at high speeds to prevent rubbing and impact.

An innovative combination of hydrodynamic pressure and permanent magnetic repulsion was observed to form a magnetic-liquid double suspension bearing with large bearing capacity.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-08-2020-0295

Owing to the development of the smaller-sized rotational machinery, the demand for the high-speed and low-resistance gas bearing increases rapidly. The research of micro gas bearing in the condition of rarefied gas state is still not satisfied. Therefore, the purpose of this paper is to present a numerical investigation of the effect of misalignment and rarefaction effect on the comprehensive performance of micro-electrical-mechanical system (MEMS) gas bearing.

The Fukui and Kaneko model is expanded to 2D solution domain to describe the flow field parameters. The finite element method is used to discretize the equation. Newton–Raphson method is used to solve the nonlinear equations for the static performance of gas bearing, and partial deviation method is adopted for the solution of dynamic equations.

The static and dynamic characteristics of MEMS gas bearing are calculated, and the comparison is made to study the influence of rarefaction effect and misalignment. The results show that the rarefaction effect will decrease bearing load capacity compared with traditional solution of Reynolds equation, and the misalignment will reduce the stability of bearing. The influence of misalignment on gas film thickness is also analyzed in this paper.

The investigation of this paper emerges the change regularity of comprehensive performance of MEMS gas bearing considering rarefaction effect and misalignment, which provides a reference for the actual manufacturing of MEMS gas bearing and for the safety operation of micro dynamic machinery.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-01-2020-0023/

This work aims to demonstrate the vibration suppression of the rotor system with localized defects on bearing using an integral squeeze film damper (ISFD).

Experiments were carried out to study the vibration characteristics of the rotor system with ISFD mounted on fault deep groove ball bearings. Three fault bearings including bearing with outer race defect, inner race defect and ball defect have been used in this paper. The results were compared by use of vibration acceleration level, continuous wavelet transform and envelope spectrum.

It was found that ISFD shows excellent damping and vibration attenuation characteristics of the rotor system with defective bearing. The fault bearing rotor system with external ISFD considerably reduces the vibration energy and amplitude compared with the system without ISFD.

There is a dearth of experimental research pertaining to vibration characteristics of rotor system support by defective bearings with ISFD. Besides, the test provides evidence for the application of ISFD in vibration control of the rotor system with incipient defects on bearing.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-04-2020-0144/

High power and speed are new demands for rotating machinery which needs the journal bearings with high dynamic characteristics. The critical speed of the rotor-bearing system is one of the most significant parameters to evaluate the dynamic characteristics. This paper aims to investigate the theoretical and experimental analysis of a rotor system supported by large diameter elliptical bearings.

To obtain the theoretical and experimental support for rotor-bearing system design, dynamic characteristics theoretical analysis based on the finite difference method is given and an experiment focuses on critical speed identification is carried out.

The theoretical calculation results indicate that the critical speed is near to 800 rpm and there is no large vibration amplitude round working speed (1,500 rpm). Using the test bench in the factory unit, vibration data including three experimental processes are obtained. According to the vibration data, the critical speed is identified which also indicates that it is stable when working at 1,500 rpm.

The design method for the rotor system supported by large diameter elliptical bearing can be obtained by the theoretical and experimental results shown in this paper.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-04-2020-0122/

The purpose of this paper is to introduce a high-speed rolling bearing test rig supported by sliding bearing and its first experimental results.

Through analyzing the disadvantages of using rolling bearing as supporting bearing, the bottlenecks that need to be resolved urgently in the development of rolling bearing experimental technology, and the advantages of the sliding bearing, this study used the sliding bearing as the supporting bearing for the high-speed rolling bearing test rig for the purpose of prolonging the service life, increasing the load capacity and promoting the operating stability.

The experimental results show that the high-speed rolling bearing test rig supported by sliding bearing could stably rotate at 70,800 rpm without installing the test bearing; the temperature of the sliding bearing is increasing with the rotating speed and the maximum is less than 95°C. Moreover, the new test rig, installing an angular contact ball bearing as test bearing, could also stably rotate at 54,000 rpm with 2 kN axial load and 1 kN radial load; the temperature of the sliding bearing is increasing with the rotating speed and the maximum temperature is less than 97°C.

Rolling test rig has been established.

This paper proposes a high-speed rolling bearing test rig supported by sliding bearing, which greatly prolongs the service life, increases the load capacity and promotes the operating stability, moreover, reduces the risk of supporting bearing failure before the test bearing. This paper can also provide a new idea and reference for the design of similar bearing test rig.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-03-2020-0085/

The tribological behavior, i.e. friction coefficient and wear rate, and vibration characteristics of the water-lubricated bearing was investigated. The water-lubricated bearing is made of three different materials, i.e. polyether-ether-ketone (PEEK), polyimide (PI) and nitrile-butadiene rubber (NBR).

The tribological behavior was investigated experimentally on a specially designed test rig. Three vibration sensors were used to record the vibration of the bearing.

The results indicated that the variation of friction coefficient with rotation speed agrees well with the trend of Stribeck curve. The tested friction coefficient of rubber bearing is higher than that of the other two bearings whether it is in the state of mixed-lubrication or hydrodynamic lubrication, and which causing a larger wear rate in rubber bearing. The PEEK bearing exhibits the best tribological properties due to it has smaller friction coefficient and wear rate. However, it can be found that the rubber bearing gives the minimum vibration acceleration, which means that the rubber bearing has the most potential to improve the stability of water-lubricated bearing rotor system.

In this study, a group of experiment studies conducted on a specially designed test rig. The comprehensive performance, including friction coefficient, vibration acceleration and wear rate, of water-lubricated bearing with three different materials, i.e. PEEK, PI and NBR, was compared systematically. The experiment research may offer a reference for the selection of material in water-lubricated bearing in specific operating conditions.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-10-2019-0447/

This study aims to uncover the influencing mechanism of the tilt angles of the cage pocket walls of the high-speed cylindrical roller bearing on the bearing skidding.

A novel cylindrical roller bearing with the beveled cage pockets was proposed. Using the Hertz contact theory and the elastohydrodynamic and hydrodynamic lubrication formulas, the contact models of the bearing were built. Using the multibody kinematics and the Newton–Euler dynamics theory, a dynamics model of the bearing was established. Using the Runge–Kutta integration method, the dynamics simulations and analysis of the bearing were performed.

The simulation results show that the effects of the tilt angles of the front and rear walls of the pocket on the bearing skidding are remarkable. Under a 5° tilt angle of the front wall of the pocket and a 10° tilt angle of the rear wall, the bearing skidding can be effectively decreased in the rotational speed range of 10,000-70,000 r/min.

In this paper, a novel cylindrical roller bearing with the beveled cage pockets was proposed; a dynamics model of the bearing was established; the influence mechanism of the tilt angles of the front and rear walls of the pocket on the bearing skidding was investigated, which can provide fundamental theory basis for optimizing the pocket.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-01-2020-0035/

This paper aims to prevent oil starvation and improve the service life of the rolling bearings.

A thrust ball bearing with magnetic circuit structure is proposed for ferrofluid lubrication. With the aid of magnetic field, ferrofluid can be maintained in the contact area of rolling bodies to delay lubricant loss. Experiments are performed to ensure the validity of the designed bearing.

Compared with conventional lubricant, service life of the ferrofluid lubricated bearing can be prolonged under magnetic field. In addition, with a proper magnetic field distribution, lubricant starvation may be limited under the conditions of present experiments.

This work provides a method to control the starved lubrication of rolling bearings with restricted lubricant supply.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-04-2020-0132/

The purpose of this paper is to analyze the force and basic rating life of angular contact ball bearings of RV reducer under the actual operating condition.

Force analysis of angular contact ball bearing under the actual operating condition, calculate the axial, radial load and internal load distribution, calculate the basic rating life of angular contact ball bearing under variable load conditions.

The external load has a great influence on the radial load of angular contact ball bearing, further affecting the basic rating life of angular contact ball bearing, which is a great influence on the overall life of RV reducer under the condition of high frequency and heavy load.

This paper provides important ideas for the design and manufacture of RV reducer in theory and experiment technology.

The purpose of this paper was to study the hydrodynamic lubrication of rough bilayer porous bearing to reveal the effect of percolation.

The seepage lubrication model of the circular bilayer porous bearing was established in polar coordinates. The digital filtering technique and Darcy’s law were used to simulate the rough surface and the percolation characteristic of the oil bearing, respectively. The influence of the structural parameters on the lubrication performance was analyzed.

Compared with the ordinary monolayer oil bearing with high porosity, the bilayer bearing can reduce the whole porosity, prevent oil infiltrating into the porous medium and have better lubrication performance. The lubrication performance of bilayer oil bearing is better than that of the single-layer oil bearing which has a higher porosity. With increasing root-mean-square roughness or decreasing surface porosity, the lubrication performance of the bilayer bearing improves. The lower the porosity of the surface layer, the better the lubrication performance.

This research provides a theoretical basis for clarifying the lubrication mechanism and influence the mechanism of the bilayer oil bearing.