A CYLINDRICAL STRAIGHT GEAR TRANSMISSION WITH EXTERNAL MESHING

摘要

The cylindrical straight gear transmission with external meshing finds application in transmission boxes, reducers, gear hydro machines, compressors, and others. By it may be transferred continuous rotational motion from one gear to another in case of small number of teeth. The transmission contains a driving (1) and a driven (2) gear with parallel axes of rotation and small number of straight teeth with nonsymmetrical profiles. The teeth have a concave (4) and a convex (3) side and are profiled by three different curves. The first one (MN), outlining the concave side (4), is an equidistant curve of an elongated epicycloid. By the second (KL), which is an evolvent curve, is profiled the convex side (3), while by the third (LM) is shaped the top of the tooth (5) as a circular arc. The concave tooth profile (4) of one of the gears is a wrapper of the relative positions, which occupy the top round profile (5) of the other gear during their turn, and the evolvent profiles (3) of the driving and driven gear are with increased length what provides for their uninterrupted meshing with a ratio of face overlapping larger than one.