Patent ID: 8461828

Claim:
A wheel speed detecting device comprising: a multi-pole magnet ring operatively mounted on a bearing fitted into a hub of a wheel; a sensor operatively mounted relative to a swing arm or a front fork via a sensor supporting member at a portion facing the multi-pole magnet ring; said wheel speed detecting device detecting the multi-pole magnet ring, which rotates together with the wheel, by using the sensor, and thereby detecting a rotation speed of the wheel from the detection information obtained by the sensor; an annular recess groove provided in an outer circumference of an end portion of the hub on a side closer to the sensor; and a cup-shaped flange portion extending from the sensor supporting member, the cup-shaped flange portion covering the annular recess groove while maintaining a predetermined gap between the cup-shaped flange portion and the outer circumference of the end portion of the hub, wherein the cup-shaped flange portion includes a disk portion extending radially outwardly from the sensor supporting member and a cylinder portion extending parallel to the outer circumference of the hub, said cylinder portion extending from an outer circumference of the disk portion.