Patent ID: 8651775

Claim:
A vibration-reduction mechanism for a gear cutting machine that performs gear cutting on a gear blank with a rotary tool attached to a main shaft made to move reciprocally by a crank mechanism, by imparting to the main shaft a twisting motion corresponding to a helical angle to be formed in the gear blank, the vibration-reduction mechanism comprising: a first balancer shaft and a second balancer shaft which are arranged in parallel to a crank shaft of the crank mechanism, and which rotate synchronously with the crank shaft at a same speed as a speed of the crank shaft, the first balancer shaft rotating in an opposite direction to a rotational direction of the crank shaft and the second balancer shaft rotating in a same direction as the rotational direction of the crank shaft; main balancer weights detachably attached onto the crank shaft so as to reduce vibrations in an axial direction of the main shaft; and sub balancer weights detachably attached onto the first and the second balancer shafts so as to reduce vibrations caused by translational unbalance between the main balancer weights in directions that are orthogonal to the axial direction of the main shaft, wherein the main balancer weights and the sub balancer weights are selected on the basis of a stroke width of the main shaft and on the basis of the helical angle to be formed in the gear blank.