| 摘要 |
A speed change mechanism comprising essentially a nutator member carried and driven by a shaft having an oblique hub which mounts the member and effects the nutating movement thereof. On each of its two sides the nutator member has rotary members coaxial with the shaft, one such member delivering the output power to a second shaft aligned with the first whereas the other rotary member is normally held stationary. The rotary and nutator members have cooperable teeth or shoulders of special shape, those on the nutator member being preferably in the form of tapered rollers whereas the shoulders on the rotary members have the shape of tooth formations. The input shaft which drives the nutator member has a pair of weights so arranged as to oppose the tendency for the member to flex the shaft during rotation of the latter. Vibration of the mechanism is thereby reduced. The tapered rollers of the nutator member are spring biased axially in a manner to yieldably maintain them in engagement with the teeth of the two rotary members, thereby eliminating looseness or lost motion and obviating the necessity for maintaining ultra-critical tolerances. That one of the rotary members which is considered to be the "stationary" one, can have a turning movement imparted to it by a speed-controlled device, thereby to effect a change in the ratio of the mechanism, or it can be coupled to the stationary casing by a releasable clutch to enable it to have free wheeling. In the latter case, an additional rotary member is provided, concentric with the clutched member and also cooperable with the nutator member, said second rotary member being also connected by means of a clutch device to the stationary casing. By maintaining one or the other of the two clutched members stationary while the other is permitted free movement, a selection of either of two speed ratios can be had. |
