Abstract: A hub unit bearing H1 includes a rotational speed detector 9 which is made up of an encoder 6 and a sensor 8. A seal 5b on a side facing a center side of a vehicle includes a primary seal 5bp and a secondary seal 5bq which are disposed in that order in an axial direction from rolling elements 32 on a side facing the center side of the vehicle towards the center side of the vehicle so as to define a primary sealed space portion I between the vehicle's center side facing rolling elements 32 and the primary seal 5bp and a secondary sealed space portion II between the primary seal 5bp and the secondary seal 5bq, with the rotational speed detector 9 disposed within the secondary sealed space portion II.

Abstract: A hub unit bearing H1 includes a rotational speed detector 9 which is made up of an encoder 6 and a sensor 8. A seal 5b on a side facing a center side of a vehicle includes a primary seal 5bp and a secondary seal 5bq which are disposed in that order in an axial direction from rolling elements 32 on a side facing the center side of the vehicle towards the center side of the vehicle so as to define a primary sealed space portion I between the vehicle's center side facing rolling elements 32 and the primary seal 5bp and a secondary sealed space portion II between the primary seal 5bp and the secondary seal 5bq, with the rotational speed detector 9 disposed within the secondary sealed space portion II.

Abstract: After a hub supporting member is mounted on an end portion of a spindle, correction work is applied to a ring-shaped supporting surface which is an end face of the hub supporting member, whereby perpendicularity of the supporting surface relative to a rotational center axis of the spindle is improved. Thereafter, while the hub main body is made to rotate together with the spindle in such a state that the mounting surface abuts with the supporting surface, grinding finishing work is applied to a cylindrical surface portion (a portion on which inner rings are fitted) of the hub main body. As a result, the perpendicularity of the mounting surface relative to the geometric center axis of the cylindrical surface portion is improved.

Abstract: After a hub supporting member is mounted on an end portion of a spindle, correction work is applied to a ring-shaped supporting surface which is an end face of the hub supporting member, whereby perpendicularity of the supporting surface relative to a rotational center axis of the spindle is improved. Thereafter, while the hub main body is made to rotate together with the spindle in such a state that the mounting surface abuts with the supporting surface, grinding finishing work is applied to a cylindrical surface portion (a portion on which inner rings are fitted) of the hub main body. As a result, the perpendicularity of the mounting surface relative to the geometric center axis of the cylindrical surface portion is improved.