Thermal Characteristics Analysis And Reliability Research Of Spindle System

With the development of machinery and equipment,the product processing begins to develop in the direction of high speed,high efficiency and high precision.The machining precision of the machine tool has been unable to keep up with the development of products for the manufacturing sector.The research found that the thermal deformation of machine tool is the main factors which cause machining error.The thermal deformation of Machine tool spindle system and the feed system is the main cause of thermal error.In this paper,the temperature distribution of the spindle system and the thermal deformation are studied,and the thermal characteristics of the spindle system are analyzed.Bearing is the key component of the spindle system.The friction heat of spindle bearing significantly affects the spindle unit on the speed and dynamics,which restricts the improvement of machining accuracy and efficiency.It is the chief source of heat.So the research of spindle bearing system is particularly necessary.The mechanics theory of rolling bearing experienced the development of statics,pseudo dynamics and dynamics.In connection with the geometry structure characteristics of angular contact ball bearing,the contact mechanics model is established which uses the static and quasi dynamic method.The deformation characteristics and the mechanical properties of rolling bearing under axial and radial load bearing are analyzed,including internal and external contact angle,contact load,contact stiffness,contact ellipse parameters,main parameter of the bearing friction.An example of calculation is given.At the same time the influence of the preload and the speed of the speed on the characteristic parameters of the bearing is analyzed.A machine as an example,as the group match bearings download charge distribution is considered,the frictional heat generated at different speeds and different preload each bearing is calculated.Spindle system thermal-structural analysis of the finite element model is established.And the calculated bearing friction heat as the heat is loaded to the model.Spindle system of temperature distribution and thermal displacement distribution are analyzed.The influence of different speed and different pre compactness on the results is presented,and some measures of reducing the temperature and heat displacement of the main shaft are proposed.Finally due to the machining process,parts of the property will inevitably appear different.According to the reliability theory in this paper,the components of the spindle thermal expansion rate and heat transfer rate as variables,the reliability model of spindle system is established.The reasonable reliability calculation method is selected for the reliability analysis of the spindle rotating accuracy.