Input gear case and bicycle that has it variable speed system of shifting

The utility model relates to an input gear case mainly includes input gear box and gear shift subassembly, and the gear shift subassembly includes the axis, is equipped with the planet carrier on the axis, planet wheel subassembly with shift gears the piece, shift gears piece and axis pass through spline sliding fit, are equipped with the ratchet structure between sun gear in the planet wheel subassembly and the axis, the both ends of planet carrier are equipped with axis the initiative taper gear and drive lid respectively, through-hole meshing that shift gears a right-hand member and drive were covered is provided with on the right box and controls piece along the shift subassembly of axial towards left side motion of shifting gears this input gear case can be very convenient the switching of realization between two grades, the utility model discloses still relate to and contain this input gear case, output gear case, transmission shaft, bicycle that lower chain stay subassembly and flower-drum the are formed variable speed system of shifting gears, it is little that this system has the fault rate, and the good reliability has characteristics such as non-maintaining, long service life, and assembly efficiency is high, and labour cost is low, high transmission efficiency, the stationarity is good, transmission advantage such as reliable