Structural Optimization And Dynamic Performance Analysis Of High-speed And Heavy-duty Roller Linear Guides

Rolling linear guide is the key functional component of machining center,CNC lathe and other mechanical equipment.Its performance greatly affects the manufacturing level of the equipment With the continuous development of mechanical equipment to high-speed and large-scale,higher requirements are put forward for performances of the guide bearing mechanism,especially the anti vibration performance.The aims of this study were to improve the performance of high-speed and heavy-duty roller linear guides.The dynamic and static characteristics of high-speed and heavy-duty roller linear guide under various working conditions were studied.The formula of static stiffness,natural frequency,kinematic friction were established,and the experimental research on static stiffness,kinematic friction and vibration mode under high-speed and heavy-duty conditions were carried out.The main research contents are as follows:(1)In this paper,the relationship between stress and strain between roller and rail contact pair is investigated based on Hertz's theory of linear contact mechanics model,and a static stiffness calculation model of five degrees of freedom for slide block is established.On this basis,the influences of preload,rolling body structural parameters and lubrication conditions on static stiffness are focused on.The conclusion of theoretical research is verified by simulation test under actual working condition and stimulated experiment,combining with the use mode and bearing condition of roller linear guide pair.Finally,the parameters setting for high speed and heavy load conditions are obtained.The research shows that the influence of preload on the static stiffness is not obvious when the slide is in preload state;In comparison,the increase of the length of arc generatrix on the roller side is more effective to improve the static stiffness,so when the roller guide pair is designed,the increase of the length of the roller's arc generatrix can effectively improve the static stiffness and the vibration resistance of the guide when the shape meets the relevant standards.(2)According to the actual working condition of the roller linear guide pair,a dynamic simulation model based on the ANSYS Workbench is established to analyze the natural frequency,and the modal experimental research is carried out by using the dynamic analysis experimental platform The comparison between the experimental results and the simulation results shows that the natural frequency is greatly related to the structure and manufacturing level.In addition,the inherent characteristics of the slider can also be adjusted by pre-tightening to obtain the ideal dynamic performance index of the guide rail pair.(3)Based on Hertz and lubrication theory,the calculation model of traction driving force and friction force of rolling body(roller)of linear guide in circulation is established,the rule and influencing factors of contact force in high-speed cycle process of rollers are studied and analyzed.The influence of structure of raceway's entrance and exit on rolling force is mainly studied.A design and calculation method of guide surface of slider track is presented based on the principle of "equal work".Assuming that the deformation energy per unit time is the same when the roller enters the bearing area,the parameter equation of guide transition surface section based on the deformation of roller contact area is derived,and the stress situation when the roller passes through the transition surface is analyzed to ensure the smooth flow of the rolling body in the roller linear guide.In the aspect of the structure design of the return device,a design method of the return device structure is proposed to improve the smoothness of the rolling body movement and reduce the noise.Combined with the knowledge of dynamics and kinematics,a design method of the structure parameters to ensure the smooth movement of the rolling body and the low motion noise is obtained through calculation.(4)The performance of the optimized product is studied through the method of simulation experiment,and the influence of the track guiding surface on the friction,noise and vibration of the slider motion is mainly verified,and compared with the products with other guiding surfaces,the superiority of the structure of the guiding surface based on the principle of Equal Work is tested;At the same time,the friction and motion noise of the product with the optimized returner are tested and compared with the product performance with on optimized returner.The data of the continuous improvement of the theoretical research are provided and the actual effect after the optimization is verified.