STRUCTURE AND FUNCTION FINAL DRIVE 3. REDUCTION GEARING Function This final drive motor is equipped with a one-stage epicycloidal reduction gear that converts the high rotation speed and low torque of the hydraulic motor into low speed and high torque at the swing pinion. Operating principle The rotary movement of the output shaft of the motor is transmitted to the gear (s1) and hence to the bevel gears (b1) which are integrated with the planetary gear (1).
Since the gear (a1) is fixed with respect to the output shaft of the hydraulic motor, the planetary gear is obliged to turn, moving with it the output shaft (2) of the reduction gearing (connected to the planetary gear by means of grooved tooth- ing). The reduction ratio of the rotation speed is described by the formula: R= Zs1/(Zs1+Za1) Zs1= number of sun gear teeth Za1= number of ring gear teeth b 1 1 2 a 1 s 1 RKS01080 10-11 SK818-5 SK820-5 turbo