Rolling contact bearing with rotational speed measuring device

A rolling contact bearing having a rotational speed measuring device, the bearing comprising

• a bearing outer ring, a bearing inner ring inward of the bearing outer ring, and the rings being shaped as to have a gap between, the rings being rotatable relatively;
• bearing rolling elements rolling between the outer and inner rings;
• a seal toward an axial side of the bearing for sealing the gap between the rings;
• the speed measuring device comprising
• a first telemetry unit in the seal and comprising a pulse transmitter connected with one of the relatively rotatable rings and telemetry electronics including an electric coil;
• a rotation speed sensor connected with the other of the relatively rotatable rings, whereby the pulse transmitter and rotational speed sensor are relatively rotatable with respect to each other sensing the relative rotation of the bearing rings;
• a second telemetry unit axially outside the bearing and axially away from the first telemetry unit, the second telemetry unit also including means therein for cooperating with the coil of the first telemetry unit for the second telemetry unit to supply the first telemetry unit with energy and for the second telemetry unit to receive signals from the first telemetry unit.