Gear shaft means supporting the rotating parts and therewith to transmit rotary motion, torque or moment of mechanical parts. Generally round rod-like metal, can have different diameters of the respective segments. Rotary movement of the machine parts is mounted on the shaft. Depending on the shape of the axes, the crankshaft axis and direct-axis can be divided into two categories. The carrier case axis, can be divided into: ① shaft, both subjected to bending moments during operation and to withstand the torque, is the most common mechanical axis, such as various gear unit shaft. ② mandrel for supporting the rotating parts only bending moments without transmitting torque, some rotation of the spindle, shaft or the like such as a railway vehicle, and some are not rotating mandrel, such as the support pulley shaft. ③ shaft, mainly used to transmit torque without bending moments, such as a crane moving mechanism long axis, automotive drive shaft and the like. In the design, the use of the gear shaft is generally nothing less than about several situations: 1, typically the pinion gear shaft (fewer gear teeth) 2, the gear shafts are generally in a high-speed (i.e., low torque level) 3, the gear As the speed of the shaft rarely slip gear, running gear are generally fixed, first, because in a high-speed, its speed is the speed of discomfort were slipping. 4, the gear shaft and gear shaft is synthesized as a whole, however, in the design, or to try to shorten the length of the shaft, the first is not conducive to long on hobbing process, and second, the support shaft is too long cause the axis to be bold increased mechanical strength (such as rigidity, deflection, bending, etc.) gear shaft processing (with 45 steel, for example): a, Nibblers two, three roughing, quenching (to improve the toughness and the shaft of the gear shaft stiffness) four, fine cars gear blanks to size five, if the shaft keyway, can be processed keyway, six, seven hobbing, tooth surface IF quenching (pinion with high-frequency quenching), quenched hardness HRC48-58 ( specific needs based on the hardness conditions, load and other factors may be) eight, nine final inspection grinding teeth, finished