抄録
We have been investigating small and high-strengthened single threaded worm gear. Previous our studies have shown that reducing thickness of worm tooth on addendum face enlarges elastic deformation of worm wheel. This proposed profile has advantages on improving contact ratio, gear efficiency, strength against impact force and fluctuation in torque. Though we have modified the profile of worm, we have not reported on a profile of worm wheel. In this paper, we propose the MUB theory that new profile of worm wheel improve contact ratio without increasing tip diameter of worm wheel. At first, we focused on meshing under base circle of worm wheel, and investigated geometrical shape on dedendum face manufactured by hob cutter. As a result, we derived formula of new profile of worm wheel for meshing under base circle. In addition, the MUB theory was verified by the experiment that used an actual worm wheel with MUB profile. It was shown that we obtained a new finding by the process of this research.
