Speed-reducing device for transmitting a rotary motion through a toothed member with precession motion

摘要

A speed-reducing device for transmitting a rotatory motion includes means for generating on a toothed member (B, E, M) a rotatory motion of the axis of the toothed member (B, E, M) around a second axis, the toothed member (B, E, M) being engaged with at least another toothed member (C) through radially arranged front teeth, different in number between the two said members, which form a bevel gear, the toothed member (B, E, M) in contact with the driving means being provided with support and restraint means which allow the inclination of its axis. In its simplest embodiment, the rotatory motion comes from a driving shaft (A) provided with an end cam (T) in contact with two toothed members (B, C), the toothed member (B) in contact with the inclined face of the cam (T) being provided with a hemispherical support (S) and a flexible coupling (Z). The use of a second cam parallel to the first and of a disk with double toothing mounted between the two cams on a swivel-bearing and simultaneously engaging the two toothed members allows to obtain a further reduction stage, through which very high reduction ratios can be achieved with a very small device and even between coaxial or aligned shafts.