DIFFERENTIAL ROTATION AUTOMATIC SPEED-CHANGING GEAR

PURPOSE:To arbitrarily select an operating speed so that a differential rotation can be effected in quick response to a change in load, by a method wherein a speed-increasing gear is combined with a sun gear system for two planetary gear mechanisms while a speed-reducing gear is combined with a ring gear system for the mechanisms. CONSTITUTION:When a driving shaft 1 is rotated a driving pinion gear 5 tends to rotate both a driving ring gear 3 and a driving sun gear 4 in the same direction. In this case, when the load force exerted on a driven shaft 18 is large, a speed-increasing run gear system receives a large resistance, therefore it is little rotated and assists a differential rotation, so that a large torque is generated on the driven shaft 18 mainly by a rotation speed-changing action of a speed-reducing ring gear system. As rotation proceeds, the rotation of the speed- increasing sun gear system becomes active concurrently with a reduction in the load, the rotating speed of the driving shaft 1 gradually approach that of the driven shaft 18, and a further overspeed rotation is effected to result in an overdrive rotation.