Patent ID: 7034521

Claim:
A wheel speed detector for detecting a relative rotating speed between an outer ring and an inner ring by means of a magnetic sensor in association with an opposite magnetic ring, wherein one of the outer ring and the inner ring is rotatable while the other is stationary, the magnetic ring is fixed to the rotatable ring and the magnetic sensor is fixed to the stationary ring; and wherein a seal device comprises a stationary seal member fixed to the stationary ring and a rotatable seal member fixed to the rotatable ring, said rotatable seal member engaging with the stationary seal member, at least in a radial direction, perpendicular to a rotary axis of the rotatable ring and said seal device seals a gap between the inner ring and the outer ring, the magnetic sensor is fixed to a radial inner surface of the stationary seal member, a normal of said radial inner surface being perpendicular to said rotary axis, the magnetic ring is fixed to a radial inner surface of the rotatable seal member and surfaces of the magnetic ring other than that fixed to the radial inner surface of the rotatable seal member are covered with a seal lip, a normal of said radial inner surface being perpendicular to said rotary axis, and a normal of said magnetic ring and a normal of said magnetic sensor being parallel to each other and being perpendicular to said rotary axis.