Pulser plate mounting structure

A pulser plate mounting structure, comprising:

• a key groove formed in an end face of a rotating wall portion formed from a crank arm and a counterweight of a crankshaft for an internal combustion engine, and
• a key portion for engaging with the key groove, the key portion being formed on a pulser plate that is superimposed on the end face, wherein the pulser plate is secured to the rotating wall portion by a securing member, the pulser plate including a pair of holes bored in the pulser plate such that each of the pair of holes extends in a peripheral direction of the pulser plate,
• wherein the key portion is formed from an arched band-shaped portion projecting in an arched shape from the pulser plate on one end face side thereof and engaging with the key groove and sandwiched between the pair of holes, and a pair of connecting portions for providing integral connection between the pulser plate and opposite ends of the arched band-shaped portion, which engage with each other, are disposed so that longitudinal directions thereof are along a radius of the pulser plate, and
• wherein opposite side faces of the arched band-shaped portion extending in the radial direction of the pulser plate are fitted to opposite inner faces of the key groove, respectively, the opposite side faces of the arched band-shaped portion facing the holes bored in the pulser plate, and
• wherein there are a plurality of locations at which there are securing parts for securing the pulser plate to the rotating wall portion by the securing member, the locations being aligned in a peripheral direction of the pulser plate, and gaps in a peripheral direction between at least one location of the securing parts and other locations of the securing parts adjacent to opposite sides of the at least one location of the securing parts are made to be different from each other.