Rotation detecting device and wheel support bearing assembly utilizing the same

Abstract

To provide a rotation detecting device with a function of transmitting a rotational speed detection signal wireless and enable the rotation detecting device to be assembled compact in size without requiring any anti-rusting treatment to a multi-pole magnet assembly and a magnetic ring assembly, the rotation detecting device includes an electric power generator () for generating an electric power by a relative rotation between a non-rotatable member () and a rotatable member (). The electric power generator () includes a multi-pole magnet assembly () and a magnetic ring assembly (). A wireless transmission device () for transmitting the rotational speed detection signal outputted by the electric power generator () is employed. A sealing member () is also employed for sealing a working space delimited between the non-rotatable member () and the rotatable member (), and the multi-pole magnet assembly () and the magnetic ring assembly () of the electric power generator () confront with each other at a location inwardly of the sealing member (). The sealing member () is mounted on the magnetic ring assembly () or the wireless transmission device () of an annular configuration.