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This paper aims to study the influence of the dimension change of bush-pin on the pressure, oil film thickness, temperature rise and traction coefficient in contact zone by using a thermal elastohydrodynamic lubrication (EHL) model for finite line contact. Concretely, the effects of the equivalent curvature radius of the bush and the pin, and the length of the bush are investigated.

In this paper, the contact between the bush and pin is simplified as finite line contact. The lubrication state is studied by numerical simulation using steady-state line contact thermal EHL. A constitutive equation Ree–Eyring fluid is used in the calculations.

It is found that by selecting an optimal equivalent radius of curvature and prolonging the bush length can improve the lubrication state effectively.

Under specific working conditions, there exists an optimal equivalent radius to maximize the minimum oil film thickness in the contact zone. The increase of generatrix length will weaken the stress concentration effect in the rounded corner area at both ends of the bush, which can improve the wear resistance of chain.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-10-2019-0448.

This study aims to investigate the influence of geometry of bush-pin pair from a perspective of optimal lubrication through a thermal elastohydrodynamic lubrication model for finite line contact.

A constitutive equation: Ree-Eyring fluid is used in the calculations. The real chain sizes, i.e. equivalent radius of curvature, bush length, length of the rounded corner area and rounded corner radius, are jointed investigated. Moreover, the effects of the length of the rounded corner area and the radius of rounded corner are investigated.

It is found that the current standard of the chain might not consider the importance of lubrication, and the lubrication state can be improved effectively by choosing an optimal radius of rounded corner and the length of the corner area.

By optimally selecting sizes, the occurrence of high pressure, high temperature rise and near zero film thickness at the ends of bush, especially under heavier load, can be effectively avoided.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-01-2020-0031/

The purpose of this paper is to study the influence of surface precision on the lubrication state of the roller chain under adequate and rare oil supply conditions, respectively.

The straightness error and roughness error of the pin generatrices were measured and the influence of surface precision on the lubrication behavior under steady state and reciprocating motion was studied through optical interference experiments.

The lubrication state is strongly influenced by the surface precision of the roller surface both under adequate oil supply and rare oil supply conditions.

In industrial applications, the machining errors of parts cannot be completely eliminated. Studying the influence of the surface precision on the lubrication behavior of pin–bush pairs can provide the experimental basis for the optimal design of the bush roller chains.

The purpose of this paper is to use elastohydrodynamic lubrication (EHL) theory to study the variation of the equivalent curvature radius “R” on the change of oil film thickness, pressure, temperature rise and friction coefficient in the contact zone between bush-pin in industrial chain drive.

In this paper, the contact between bush and pin is simplified as infinitely long line contact. The lubrication state is studied by numerical simulation using steady-state line contact thermal EHL. The two constitutive equations, namely, Newton fluid and Ree–Eyring fluid are used in the calculations.

It is found that with the increase of equivalent curvature radius, the thickness of oil film decreases and the temperature rise increases. Under the same condition, the friction coefficient of Newton fluid is higher than that of Ree–Eyring fluid. When the load increases, the oil film thickness decreases, the temperature rise increases and the friction coefficient decreases; and the film thickness increases with the increase of the entraining speed under the condition “R < 1,000 mm”.

The infinite line contact assumption is only an approximation. For example, the distances between the two inner plates are 5.72 mm, by considering the two parts assembled into the inner plates, the total length of the bush is less than 6 mm. The diameter of the pin and the bore diameter of the bush are 3.28 and 3.33 mm. However, the infinite line contact is also helpful in understanding the general variation of oil film characteristics and provides a reference for the future study of finite line contact of chain problems.

The change of the equivalent radius R on the variation of the oil film in the contact of the bush and the pin in industrial chain drive was investigated. The size effect influences the lubrication characteristic greatly in the bush-pin pair.