Abstract: It is prevented that magnetic foreign matter adheres the magnet encoder 3a to deteriorate the reliability of rotation speed detection with the sensor 4a. The encoder 3a is provided on the outside of the combined seal ring 19 with reference to the bearing interior space 24, and the sensor 4a faces the encoder 3a. The knuckle 21 is placed close to the housing 33 of the drive shaft member 28 of the constant velocity joint 27 to form a labyrinth seal 20. The width of the clearance of this labyrinth seal 20 is up to 40% of the pitch of adjacent S-poles and N-poles that are arranged on the detected surface of the encoder 3a. With this construction, larger foreign matter is prevented from attaching to the detected surface of the encoder 3a to solve the above subject.

Abstract: A sensor for detecting a speed of rotation is an active sensor, a sensing portion 35 of the sensor directly faces the magnetic encoder 10 without interposition between it and the encoder 10, and a harness 34 (or connector) of the sensor 30 for detecting the speed of rotation is taken out of a gap between a knuckle N and a constant velocity universal joint 9.

Abstract: Attachment holes are formed in a plurality of locations in the circumferential direction of the attachment flange of a wheel bearing unit. The amount “h” of projection from an attachment surface in the axial direction of the opening edge peripheral portion of the respective attachment holes is limited under the condition that studs are press-fitted and fixed into the respective attachment holes.

Abstract: The rotor of a braking apparatus is fitted onto a cylindrical positioning portion 19a, and in this condition, fixed to the hub 8a using bolts which are threaded into the screw holes 11a in the rotating flange 10a, and tightened. As the hub 8a rotates, the runout in the radial direction of the outer peripheral surface 20a of the cylindrical positioning portion 19a is controlled up to 15 ?m, to suppress the runout of the vehicle wheel. With this construction, running performance such as riding comfort and diving stability is improved.

Abstract: Attachment holes are formed in a plurality of locations in the circumferential direction of the attachment flange of a wheel bearing unit. The amount “h” of projection, from an attachment surface in the axial direction of the opening edge peripheral portion of the respective attachment holes is limited to no larger than 10 ?m under the condition that studs are press-fitted and fixed into the respective attachment holes. By this configuration, it is possible to inhibit the runout of the rotor fixed to the attachment surface of the attachment flange and thereby inhibit the judder generated during braking operation.

Abstract: In a wheel supporting rolling bearing unit, both end openings of a space in which balls 14, 14 are provided are sealed with seal rings 16c, 16d each having two to three seal lips. A rolling resistance that changes based on a preload is regulated in a range of 0.15 to 0.45 N·m, and a total running resistance of both seal rings 16c, 16d based on a friction between the seal lips and counter surfaces is regulated in a range of 0.06 to 0.4 N·m.

Abstract: Respective constituent members of a wheel bearing unit 5 are assembled and also a cover 74 is fixed to an inner end portion of an outer ring 6. The wheel bearing unit 5 is fitted to a turning machine 38 in a state that a space in which an encoder 72 is provided is sealed tightly from an outside by fitting a stop plug 96 into an insertion hole 84 provided in the cover 74. A top end portion of a rotating shaft 40 of a turning machine 38 is engaged with an engaged concave portion 102 provided to a hub 8a. A turning process is applied to an outer side surface of a rotary flange 13 while turning the hub 8a around the outer ring 6 by the rotating shaft 40, and thus the outer side surface is processed in predetermined shape and dimension.

Abstract: A sensor for detecting a speed of rotation is an active sensor, a sensing portion 35 of the sensor directly faces the magnetic encoder 10 without interposition between it and the encoder 10, and a harness 34 (or connector) of the sensor 30 for detecting the speed of rotation is taken out of a gap between a knuckle N and a constant velocity universal joint 9.

Abstract: In a wheel supporting rolling bearing unit, an inner end opening out of both end openings of a space in which balls 14, 14 are provided is sealed with a cap 17a. An outer end opening is sealed with a seal ring 16c having three seal lips. A rolling resistance that changes based on a preload is regulated in a range of 0.15 to 0.45 N·m, and a running resistance of the seal ring 16c based on a friction between the seal ring and a counter surface is regulated in a range of 0.03 to 0.2 N·m.

Abstract: The outer race 2 is fixed to the support hole 29 in the knuckle 1, and the constant velocity joint 6 is connected to the hub 3. The first seal ring 9 is fitted into the outer race 2 to cover the opening on the end of the bearing space 26. The seal ring 28 is fitted into the support hole 29 to cover the opening on the end of the detection space 27. The encoder 7 is fitted onto the inner race 4, and the outer peripheral edge of the encoder 7 faces the inner peripheral surface on the outer race 2 in an adjacent arrangement relationship to form a labyrinth clearance 36, so that grease within the bearing space 26 is prevented from leaking toward the detection space 27, whereby the rotation resistance is small to improve parts of the automobile in acceleration and fuel consumption.

Abstract: Rotation torque of the hub rotating together with the road wheel is reduced to improve the driving performance of the vehicle such as acceleration performance, fuel consumption. The opening at both ends of the space where balls 14, 14 are provided is covered by seal rings 16c, 16d each having two or three seal lips. The whole rotation torque of the both seal rings 16c, 16d based on the friction between the seal lips and the mating surface is reglated between 0.06 N·m and 0.4 N·m.

Abstract: A cylindrical liner 29 made from steel is inserted into a knuckle 3b made from a light alloy, when casting the knuckle. Then, an outer ring 6b constituting a wheel bearing unit is internally secured to the inner diameter side of the liner 29. The finishing-process of double row outer ring raceways 11a and 11b formed on the inner peripheral surface of the outer ring 6b may be performed prior to internally securing the outer ring 6b to the liner 29. Since it is not necessary to set a knuckle 3b, which is large and complex in shape, into processing equipment to perform finishing-process of the respective outer ring raceways 11a and 11b, it realizes a structure enabling a reduction in the total weight and the number of assembling steps, of the knuckle and the wheel bearing unit, thereby reducing the total manufacturing cost.

Abstract: An inner diameter-side cylindrical member 37 of a supporting ring 36 is externally fitted on a shoulder 35 of an inner ring 3 constituting a hub. An encoder 29a is supported on the outer peripheral surface of an outer diameter-side cylindrical portion 38 constituting the supporting ring 36. Further, to a metal core 30a internally fitted to an outer ring 1 is supported and fixed a rotation-detecting sensor 21b, and also a proximal end portion of a seal member 44 is connected and fixed thereto. An edge of at least one of seal lips 45a, 45b, 45c of the seal member 44 is brought to be in sliding contact with the supporting ring 36 around the entire circumference. Since the rotation-detecting sensor 21b and the seal member 44 are supported by the core metal 30a, a rolling bearing unit can be downsized.

Abstract: In a wheel supporting rolling bearing unit, an inner end opening out of both end openings of a space in which balls 14, 14 are provided is sealed with a cap 17a. An outer end opening is sealed with a seal ring 16c having three seal lips. A rolling resistance that changes based on a preload is regulated in a range of 0.15 to 0.45 N·m, and a running resistance of the seal ring 16c based on a friction between the seal ring and a counter surface is regulated in a range of 0.03 to 0.2 N·m.

Abstract: In a wheel supporting rolling bearing unit, both end openings of a space in which balls 14, 14 are provided are sealed with seal rings 16c, 16d each having two to three seal lips. A rolling resistance that changes based on a preload is regulated in a range of 0.15 to 0.45 N·m, and a total running resistance of both seal rings 16c, 16d based on a friction between the seal lips and counter surfaces is regulated in a range of 0.06 to 0.4 N·m.

Abstract: An inner diameter-side cylindrical member 37 of a supporting ring 36 is externally fitted on a shoulder 35 of an inner ring 3 constituting a hub. An encoder 29a is supported on the outer peripheral surface of an outer diameter-side cylindrical portion 38 constituting the supporting ring 36. Further, to a metal core 30a internally fitted to an outer ring 1 is supported and fixed a rotation-detecting sensor 21b, and also a proximal end portion of a seal member 44 is connected and fixed thereto. An edge of at least one of seal lips 45a, 45b, 45c of the seal member 44 is brought to be in sliding contact with the supporting ring 36 around the entire circumference. Since the rotation-detecting sensor 21b and the seal member 44 are supported by the core metal 30a, a rolling bearing unit can be downsized.

Abstract: Respective constituent members of a wheel bearing unit 5 are assembled and also a cover 74 is fixed to an inner end portion of an outer ring 6. The wheel bearing unit 5 is fitted to a turning machine 38 in a state that a space in which an encoder 72 is provided is sealed tightly from an outside by fitting a stop plug 96 into an insertion hole 84 provided in the cover 74. A top end portion of a rotating shaft 40 of a turning machine 38 is engaged with an engaged concave portion 102 provided to a hub 8a. A turning process is applied to an outer side surface of a rotary flange 13 while turning the hub 8a around the outer ring 6 by the rotating shaft 40, and thus the outer side surface is processed in predetermined shape and dimension.

Abstract: The wheel rim of a vehicle wheel is fitted onto a cylindrical positioning portion 19a, and in this condition, fixed to the hub 8a using bolts which are threaded into the screw holes 11a in the rotating flange 10a, and tightened. As the hub 8a rotates, the runout in the radial direction of the outer peripheral surface 20a of the cylindrical positioning portion 19a is controlled up to 15 ?m, to suppress the runout of the vehicle wheel. With this construction, running performance such as riding comfort and diving stability is improved.

Abstract: The rotor of a braking apparatus is fitted onto a cylindrical positioning portion 19a, and in this condition, fixed to the hub 8a using bolts which are threaded into the screw holes 11a in the rotating flange 10a, and tightened. As the hub 8a rotates, the runout in the radial direction of the outer peripheral surface 20a of the cylindrical positioning portion 19a is controlled up to 15 ?m, to suppress the runout of the vehicle wheel. With this construction, running performance such as riding comfort and diving stability is improved.

Abstract: A concave groove 38 is formed all the way around the circumference on a part of an installation surface 14 having its center at the central axis of a hub 8, such that it is concave inward from the installation surface. Also, installation holes 15 for press fitting studs 9 thereto are opened on a substantially middle section in the width direction of a bottom section of the concave groove 38. When W is taken to be the width of the concave groove in the radial direction and d is taken to be the inner diameter of the installation holes, then W=d+(5 to 25 mm). By this configuration, it is possible to inhibit the deformation of the installation surface 14 by the press insertion of the studs 9, so the above problems can be solved. Thereby, judder is prevented from occurring during braking by inhibiting runout of the rotor 2 fixed to the installation surface 14 of the installation flange 13.