Mechanism And Experimental Study On Planetary Roller Screw Roller Manufactured By The Cold Rolling Forming Process

The planetary roller screw is a kind of transmission part which converts the rotation motion into the linear motion.It has the advantages of high running speed,strong bearing capacity,good environmental adaptability and long service life.At present,the processing method of planetary roller screw roller is still partial to the traditional,so many problems are existed such as the low quality stability,high cost and low manufacturing efficiency,which limits the application and promotion of the mechanism in practice.The cold rolling forming process,as an advanced cutting-free processing method,has the advantages of high production efficiency,low material consumption,and good forming performance,which meets the green,efficient and precise process requirements of modern manufacturing.Therefore,this paper takes the cold rolling forming method of the roller as the object,and studies the geometric design method of the rolling wheel,the calculation of the force energy parameters,the material flow mechanism and the influencing factors of defects.It provides a theoretical basis for the selection or design of cold rolling forming equipment,the optimization of process regulations,and the design of rolling wheels.The main research contents of this article are as follows:(1)The geometric design method of roller for cold rolling forming is studied.the calculation method of roller theoretical tooth shape parameters under zero interference of planetary roller screw is derived based on space meshing principle,and the final modified tooth shape of roller is obtained by combining with error analysis,which is used as the design basis of roller teeth.According to the structural characteristics of the roller,the structural form of the roller is determined.The mathematical relationship between the installation phase of roller and the design phase of roller wheel is analyzed,and the fine adjustment method of initial installation phase of roller is proposed.(2)The theoretical model for calculating the contact area and maximum forming force in the rolling process is derived.the spatial problem is planarity,and the conjugate curve solution model under the compound motion of the rotation and feed of the rolling wheel is established.After the tooth height growth in the forming process is considered,the contact curve of the roller and the workpiece at different feed rates is calculated,and the contact area is obtained.The slip line field of the maximum plastic deformation surface(the plane passing through the axis of the workpiece and the roller)in different contact areas is established.The calculation method of unit pressure of contact surface is derived,and the calculation formula of the maximum forming force is given.(3)The research on the material flow mechanism and defect influencing factors in the rolling process is carried out.With the help of the finite element software DEFORM-3D,the material flow law during the workpiece rolling process is analyzed,and the root cause of the formation of the tooth crest groove defect is found.Combined with the concept of effective tooth height rate,the influence weight of roller speed,feed speed,friction coefficient and thread angle on the formation of tooth crest defect is explored by using the Point-tracking function,which is the control of roller crest defects in actual production and processing Provided reference basis and technical support.(4)The experiment of roller cold rolling pressure energy parameters is completed and compared with the theoretical analysis and Finite Element Analysis(FEA)results.The parameters,structure and machining range of the experimental platform are introduced.The cold rolling experiment is carried out to obtain the characteristics of the force and energy parameters of the four forming stages.The maximum forming force and moment under five sets of process parameters are obtained from three aspects: theoretical derivation,FEA and experimental measurement,which verified the correctness of theoretical calculation and FEA,and provide ideas for the selection of process parameters in actual production.