Mechanical Joints Micro-mechanism Elementary Exploration And Application

Mechanical joints are natural structure in all Mechanical System. The dynamical characteristic of rigidity and damping will behave when loaded, which will affect greatly on the whole system. The elasticity and the damping in mechanical joints are often stronger than that in itself. So mechanical joints have an important effect on the dynamic characteristic of the whole machine tools. Therefore, there are great influences on studying the dynamic characteristic of the machine joints. It is a precondition to accurately predict characteristic and improve the functions of mechanical structures. The research of mechanical joints is divided into two parts, the macro part and the micro part. For the macro part, springs and dampers model are introduced to express mechanical joints and the vibration system model is built. For the other part, characteristic of the mechanical joints are analyzed through experiments which are based on theories of the mechanism in physics and damping attributions of the mechanical joints. Generally speaking, in order to recognize characteristic of mechanical joints, the research in micro fields usually comes first.This thesis is a part of basic applied researching projects of Yunnan Province, which is named "The theory and applied research of dynamic characteristic of the mechanical joints". Based on the research status at home and abroad, this paper studies the dynamic characteristic of the typical plane mechanical joints. Equivalent parameters of the mechanical joints are identified through the combination of finite element analysis and experimental modal analysis. By studying the dynamic characteristic of interactive mechanical joints which have different surface roughness, contact area and vertical pressure, the effect of surface roughness, different contact areas and vertical pressure on equivalent parameters is analyzed. Through the analysis, we know that elasticity and damping of the mechanical joints are enhancing along with increasing of the vertical pressure and contact surface area, declining along with increasing of the surface roughness.This thesis, aiming at the fractal feature which exists in mechanical surface and using the fractal theory, two mutually contacts surfaces are transformed into numerous random contractual micro convex bodies. Theoretical contact model of numerous irregular array micro convex bodies is established according to the classics contact theories from the analysis of a pair of micro convex body contact. From the micro aspect, the elasticity and the damping causes and changing rules are preliminary explored, and the micro contact deformation theory is put forward through the analysis of empirical datum and the simulated data. The damping production reasons are exploratory manner analyzed from the energy loss angle in the foundation of the predecessor studied.In the actual working environment, the whole structure will be greatly influenced by mechanical joints. In order to show the effects of the mechanical joints in engineering applications, in this thesis, ANSYS software is used to analyze the distinction between the rigid body and joints, and the distinction between the natural frequencies and modal is showed. The foundation of converting theoretical study of mechanical joints to the practical application has been laid.