The Research Of Planetary Roller Screw Stiffness Based On Direct Method

In recent years, with the requirement of equipment manufacturing industry on the machining efficiency and the precision in linear displacement increasing, the requirements for mechanical properties of machine tool transmission system increases.The planetary roller screw arises at the historic moment. Compared with traditional linear motion unit ball screw, it has the advantages of high load, high speed, high precision, smooth movement and high transmission efficiency. Therefore, it has wide application prospect.The establishment of planetary roller screw stiffness model and validation of the model has been studied in this paper. First of all, the model of the ideal of the planetary roller screw was established based on the TRIZ theory, verifid the importance of planetary roller screw stiffness relative to its mechanical properties; then from its structure, the optimization method of compound shape on the planetary roller screw gear modification coefficient has been put forward; on the basis of that, the planetary roller screw parameter design software was developed with VB, which provides convenience for the establish of stiffness model and 3d model; Then the rigidity of the roller screw has been calculated from three aspects of component stiffness, contact stiffness and body stiffness, then components overall stiffness has been solved on the basis of direct stiffness method. Followed by that, the planetary roller screw ‘external forces – stiffness’ curve was drawn.In order to verify the correctness of the optimization method of compound shape on gear modification coefficient, the ADAMS virtual prototype has been analyzed; Then the component modal analysis and influencing factors of modal analysis has been carried on with ANSYS, then, methods to increase component stiffness and limit speed has been put forward; Followed by that, the contact analysis on simplified component model has been carried on with ANSYS, validate the correctness of stiffness model. Then the planetary roller screw error source and error value of each part has been analyzed, which has a great important significance on improving the transmission accuracy. Based on the stiffness model, planetary roller screw performance analysis software was developed with MATLAB, which facilitate the development and application of products.