AUTOMOBILE TRANSMISSION GEARED SHAFT AND THE MANUFACTURE METHOD

A manufacturing method of an automobile transmission geared shaft, which manufactures a solid and light geared shaft at a low cost by selecting proper materials, separately manufacturing a shaft and gears using the materials and coupling the shaft and the gears to each other in an efficient manner, thereby making a geared shaft, and the automobile transmission geared shaft manufactured by the method are provided. A manufacturing method of an automobile transmission geared shaft comprises: making a shaft(10) for composing a geared shaft(1) such that an external form of the shaft is completed by using a pipe made from an S45C material and reducing a portion of the pipe having a small diameter; machining various grooves(11) on an outer surface of the shaft, and performing an outer surface machining process and a surface treatment process required for assembling the shaft with the ring; forging an SNCM steel workpiece, manufacturing a product in the form of a ring using the forged SNCM steel workpiece, and connecting the ring to the shaft by cooling the shaft and heating the ring, thereby reducing the diameter of the shaft and expanding the inner diameter of the ring after allowing an inner diameter of the ring to have a positive tolerance such that the inner diameter of the ring is shorter than an outer diameter of the shaft; and completing gears(20,20') by machining gear teeth on an outer surface of the shaft and centering the machined shaft after connecting the ring and the shaft to each other by welding contact portions of the ring and the shaft.