Patent ID: 8376866

Claim:
An unbalance correction device of a propeller shaft, comprising: a propeller shaft comprising a plurality of annular dampers each comprising elastic members mounted along an axial direction between a metallic outer shaft and a metallic inner shaft; and a balance weight comprising a primary weight plate part and an auxiliary weight plate part that are formed in an arc shape along a width direction and comprising a substantially quadrilateral planar shape that are formed continuously and integrally along a longitudinal direction, and a protruding piece is protrusively formed on a concave arced surface on a rear surface side of the primary weight plate part and from each corner part at four locations, wherein the primary weight plate part is disposed in a non-mounted area of the plurality of annular dampers at an axial direction end of the outer shaft with a longitudinal direction of the balance weight coinciding with an axial direction of the outer shaft, and the balance weight is configured such that only the protruding piece comes in contact with and is welded to an outer peripheral side face of the outer shaft, and wherein a curvature radius of a rear surface side of the primary weight plate part is greater than a radius of the outer shaft, and a center of the curvature radius of the rear surface side of the primary weight plate part coincides with a center of a radius of the outer shaft in a state where the balance weight is disposed on the outer peripheral side face of the outer shaft.