Patent ID: 8419288
Filing Date: 2013-04-16
Classification: B60B,F16C,F16J,G01P

Abstract:
1. A hub unit bearing comprising: an outer ring having a primary inner circumferential raceway on a side thereof which faces an outermost side of a vehicle and a secondary inner circumferential raceway on a side thereof which faces a center side of the vehicle; an inner ring including: rolling elements interposed between the primary inner circumferential raceway and the primary outer circumferential raceway on a side facing the outermost side of the vehicle; rolling elements interposed between the secondary inner circumferential raceway and the secondary outer circumferential raceway on a side facing the center side of the vehicle; an outermost side facing seal provided on the side of the outer ring which faces the outermost side of the vehicle for sealing a space defined between the inner ring and the outer ring and a center side seal provided on the side of the outer ring which faces the center side of the vehicle for sealing the space defined between the outer ring and the inner ring; and a rotational speed detector made up of an encoder mounted on the side of the inner ring which faces the center side of the vehicle and a sensor held in a sensor case mounted on the outer ring, wherein the center side seal comprises a primary seal and a secondary seal which are disposed spaced apart from each other in an axial direction from the rolling elements on the side facing the center side of the vehicle towards the center side of the vehicle and has a primary sealed space portion between the rolling elements on the side facing the center side of the vehicle and the primary seal, and a secondary sealed space portion between the primary seal and the secondary seal, and the rotational speed detector is disposed in the secondary sealed space portion, wherein the secondary seal including at least one seal lip, and the at least one seal lip is brought into sliding contact with an inner circumferential surface of the sensor case mounted on the outer ring so as to form a seal portion, wherein the secondary seal is separated from the primary seal and the rotational speed detector, and wherein the secondary seal is fitted on to a stepped portion that has a reduced diameter and is formed on an outer circumferential surface of the inner ring element.