BACKLASH ELIMINATOR

摘要

A backlash eliminator capable of eliminating backlash with low loss while suppressing friction and heating by reducing backlash eliminating force. The backlash eliminator comprises an input shaft (15) connected to a driving motor (20) and having a drive gear (52), a fixed countershaft (16) arranged parallel with an output shaft (14) to which a gear (W) to be machined is fixed and which has a driven gear (42) and having large counter gears (62, 72) meshed with the drive gear (52) and small counter gears (63, 73) meshed with the driven gear (42), and a movable countershaft (17). The backlash eliminator further comprises a selection control valve (31) for so axially pressing the movable countershaft (17) that an output-side backlash eliminating torque (Ts) between the driven gear (42) and the small counter gear (73) can act in the same direction as the direction in which the cutting load torque (Tw) is generated along the circumference of the gear (W) to be machined while the gear (W) is machined.