Study On Controllable Profile Modification Technology Of Worm Gearing

Worm gearing is a widely-used mechanical transmission form in many fields such as metallurgy, chemical, architecture, shipping and machine tool and so on. It is a typical space meshing transmission. The enveloping hourglass worm gearing is applied specially abroad owing to its advantages of high load capacity, good lubrication capability, high transmission efficiency and tooth surfaces grinded precisely. However, it is multi-line contact, which makes this kind of transmission be specially susceptible to misalignment and assemblage errors and load-dependent deformation. Aimed at the defect, the paper made a in-depth research on the meshing theory and modification theory of the enveloping hourglass worm gearing from the following aspects:â‘ Based on gear conjugate theory, the tooth surface equation of hourglass worm gearing with line flank is obtained. The contact line on the worm gearing is resolved. According to the results from running-in, the profile modification on the worm is got.â‘¡After applying numeric modeling method and meshing equation on the worm drive, the solid model of the worm and the wheel is modeled. Based on the relation between the worm and the wheel, an assembly model of the worm drive is acquired. The contact analysis of the worm drive under the rigid and elastical condition is finished. The contact zone on the wheel is analyzed under the different errors. These results give a guide-line to profile modification of the worm gearing.â‘¢The profile modification on worm surface is applied to reduce the influence of the errors to edge contact on the wheel. The helical modification on the worm is used to avoid the interference of entry and exit side on the worm, to reduce the transmission errors, to balance the load share among contact tooth pairs.â‘£The process plan of the worm drive is finished. The worm and the wheel is machines on the workshop. The variable centric distance, profile modification and helical modification on the worm is tested on the worm grinding-machine. The experiment of initial contact zone is completed. The experimental results shows that it is feasible to apply this profile modification in factory.