Worm Drive Principle And Research For New Type Involute Spiroid Gearing Pairs

Cone worm drive is applied in a wide range, especially in the conditions of the compact structures, which require high transmitted power, high ability to bear impact strength, smooth operation and adjustable backlash over the middle transmission ratio or above. Compared with the other forms of gear drive ,Cone worm drive has a more compact structure,a larger number of contact teeth; a better Lubrication Conditions due to contact characteristics which is conducive to the formation of hydrodynamic oil film; a more smooth working status which is conducive to axial positioning and lateral gap control; a small sliding velocity between conjugate plane; And steel can be used to manufacture turbine on behalf of copper, realizing steel worm-steel turbine drive with good results; also it can achieve large transmission ratio, single-stage transmission ratio can reach up to i₂₁= 10-4000, and the efficiency is not too low, and many other advantages.Today the most important form of cone worm drive is Archimedes spiral cone worm, and the tooth face of Archimedes worm, Archimedean screw helicoid, is not a developable surface, that is, the surface along the normal straight generatrix is a distorted direction.The existing design and manufacturing of Cone worm drive is built on the engineering approximation, although the advanced means of calculating can be adopted, the designing and manufacturing remains complex. Thus resulting in the difficulties in tooth surface manufacturing, Grinding Wheel Dressing is needed for high precision grinding, which is not convenient than involute worm.As the worm is the key of worm-worm gear pair, the worm gear surface cut by worm gear hob and worm gear shaving cutter according to the law of dual method is not a developable surface, difficult to grinding ,regardless of what form the basic worm is.The fundamental reason for processing difficulties is that there is not a tooth profile which meets the requirements of transmission and is easy to manufacture. Most of the existing production of cone worm-worm gear pair is complex because of its special tooth profile, which is manufactured in the complex specialized machine. The equipment is expensive, and it is difficult to achieve the precision in theory of the worm-worm gear, the Finish Machining of tooth surface processing is also difficult, thus limiting its drive to further improve performance.Compared with other tooth meshing, the involute profile has the following advantages:(1)Involute gear profile meshing provided facilities for the use of generating method for cutting tooth;(2)Involute profile meshing can be shifted to implement the amendment,it will help enhance the strength of the tooth, together with the center distance, there must have made the show into a cutting angle can be achieved Cutting tool regrinding tool beyond the right gear, just to change the coefficient. Blade-shaped blade at the same time simple and re-grinding and re-grinding after a simple blade shape can change for a reasonable configuration tool tooth is very key issue.In this paper, a new type of conical worm gear drive was proposed.The main research contents of this paper are as following:(1)A new involute worm drive cone pair, and its engagement principle is based on the linear space with the interlace contact axis spiral gear drive, their basic characteristics are the basic characteristics of both sides of the cone worm tooth surface is made up of various columns on the base Direct bus to a different helix angle of the base circle spiral movement generating two different lead of the involute helical surface, and on both sides of cone worm gear tooth is involute by the end cut-off spiral-shaped along a different angle so spiral movement generated involute helicoid, which is equivalent to the inner cylinder gear and the outer mesh surface mesh face, worm gear meshing with the worm drive for the straight-line access to the instantaneous contact;(2)The tooth contact line speed, the force of the new involute profile of the worm drive was analyzed to prove that the tooth surface contact line and the relative sliding velocity is almost at right angles to the direction, so that it is conducive to create a good lubrication conditions, and stress analysis provide the theoretical basis for the follow-up calculation of strength of the Worm and checking stiffness;(3)Based on the analysis of driving form, the structure of the composition and working principle of the new type of cone worm gear-cone worm pair, the principle of determining the geometric parameters of the new cone worm drive was described, the steps was established for calculating and designing the geometric parameters of cone worm and tooth surface of cone worm gear, installation geometric parameters and structure geometric parameters, calculation formula is derived. And the accuracy, feasibility and practicality of the designing calculations was argued by examples of calculating. To put design and calculation methods and steps for such a worm drive into practice and to lay the foundation for further research manufacturing and application; (4)Kinematics simulation was carried out using the three-dimensional simulation software of the built three-dimensional model, the result data shows that the cone worm gear and the cone worm can maintain a constant speed ratio, the contact area is in a good steady state, the designed cone worm can meet the original purpose of the design. And processing method of the new type involute profile cone worm drive was talked preliminary, a available method was proposed.Today cone worm drive has been more and more applied to farm machinery,lifting machinery, machine tools and a variety of military equipment and other machinery,but by contrast to today's practical cone worm,cone worm gear drive we can see that a cone worm-cone worm gear drive constituted using cylindrical involute spiral surface, meet with the shaft's vertical cross-mating , and also the design, calculation is simple. If this new type of involute profile cone worm drive is designed to create the realization of the exhibition into the new car gear machine tools, we can provide high productivity, high-quality, low-cost means of processing for cone worm, cone worm gear drive, and promote and expand its applied areas strongly.