| 摘要 |
PURPOSE: To prevent the stop of a vehicle by providing selector means whereby the appropriate one of a forward drive transmission means and a reverse drive transmission means is automatically coupled between a drive shaft and first and second driven shafts according to the direction of rotation of the drive shaft. CONSTITUTION: An annular auxiliary gear 32 moves axially between an advanced position in which the teeth 36, 40 of an intermediate annular gear 38 are engaged and a retreated position in which lateral teeth 46, 50 are engaged, and selects either of the positions. By moving axially for engagement with one set of teeth, the annular auxiliary gear 32 automatically leaves the other set of teeth; i.e., helical teeth 30, 34 and the annular auxiliary gear 32 constitute selector means. Further, since drive is transmitted via the teeth of helical gears, axial thrust is generated between the meshing parts of the teeth, and when drive is transmitted to the gear 32 with the direction and angle of inclination of the spline 30 being in one specific direction, then the gear 32 moves axially and is selected to drivingly engage with the appropriate one of the intermediate annular gears 38, 48.
|
