Research on dynamic characteristics of oil-bearing joint surface in slide guides

Abstract

The application of oil-bearing joint that is widely used in various mechanical equipment can effectively improve the dynamic characteristics of integrated machineries. A fractal contact model of oil-bearing joint considering the effect of asperity interaction is proposed in this article. The equivalent stiffness and damping of oil-bearing joint are divided into a solid contact portion and a liquid contact portion. On the basis of elastic mechanics and fractal theory, the deformation of a single asperity of solid contact part is deduced. The stiffness and damping model considering the asperity interaction are obtained from the relationship between normal load and deformation. The stiffness and damping expression of the liquid contact part are also deduced based on the generalized Reynolds equation. It is concluded that the equivalent stiffness increases with the increase of the fractal dimension and the decrease of the fractal roughness parameter. At the same time, increasing the hydrodynamic viscosity can demonstrably improve the contact stiffness. Experiment shows that the proposed model is more in line with the actual load-stiffness relationship. The model considers the factor of asperity interaction and provides a theoretical basis for predicting the dynamic characteristics of oil-bearing joint.

Highlights

• An accurate theoretical model of the dynamic characteristics for the oil-bearing joint surface was established.

• Identification of the dynamic properties of the oil-bearing joint surface using frequency response functions.

• The factors influencing the stiffness of solid portion and liquid portion were studied, respectively.

Keywords:

• Dynamic characteristics
• mechanical joint
• frequency response function
• fractal theory

Additional information

Funding

This work was supported by the National Natural Science Foundation of China under grant 51975112, 51575365; Funds for Central Universities under grant N180305032; and Project of Promoting Talents in Liaoning Province under grant XLYC1807065, XLYC1807063.