Wheel hub assembly

A wheel hub assembly includes an internally ventilated brake disc. The brake disc is mounted on a flange-like extension of the inner bearing ring of the assembly. Slots are formed in the flange-like extension and the brake disc acts as a cover over the slots forming cooling channels extending radially outwardly in the wheel hub assembly to the cooling apertures in the radially outer part of the brake disc. A heat insulated cover disc can be positioned between the brake disc and the slots in the flange-like extension.

SUMMARY OF THE INVENTION 
The present invention is directed to a wheel hub assembly with an 
integrated rotary constant velocity joint and a flanged-on brake disc. The 
assembly includes a wheel carrier with an outer bearing ring connected to 
the wheel carrier and an inner bearing ring provided with cooling 
channels. 
A known wheel bearing in which the annular part of the wheel hub is 
provided with apertures for achieving a ventilation effect is disclosed in 
German Offenlegungsschrift No. 30 25 757. 
In the arrangement set forth in the prior art, the openings for providing 
the ventilation or cooling effect are provided in a separate operation. As 
a result, the component containing the openings has greater length and the 
air flow cross-sections are relatively small so that a reduced ventilating 
or cooling action results. 
Therefore, it is the primary object of the present invention to provide a 
wheel hub assembly which can be ventilated to improve the cooling action 
with a shorter length for the component forming the cooling channels. The 
invention is characterized by the fact that the operation of forming the 
channels does not result in any additional costs and it is possible to 
provide coolant channels or passages which have a relatively large 
cross-section for the cooling air flow. 
Accordingly, the invention has the following characteristic features: 
(a) a flange-like extension is formed on the inner bearing ring and is 
arranged to mount an internally ventilated brake disc, and the flange-like 
extension has uniformly circumferentially spaced, radially extending 
through-slots; 
(b) the through-slots are located in the outside surface of the flange-like 
extension and the slots are covered along their length and at the 
circumference of the extension by the internally ventilated brake disc; 
and 
(c) the inner bearing ring has a central bore located inwardly of the 
flange-like extension and the bore is arranged to receive a cover plate 
containing beads corresponding to the slots with the beads extending 
radially inwardly into the cover plate. 
An important feature of the wheel hub assembly embodying the present 
invention is that the slots in the flange-like extension are formed in the 
operation of forging the inner bearing ring and the cooling channels are 
completed by mounting the brake disc on the wheel hub assembly. 
In another embodiment of the invention, a preferably heat-treated insulated 
cover disc can be positioned between the flange-like extension on the 
inner bearing ring and the internally ventilated brake disc. 
The advantage of this feature is that the heat transmitted from the brake 
disc to the wheel hub, which is low because the two parts are in contact 
with one another only over the surfaces between the slots, is further 
reduced. 
The various features of novelty which characterize the invention are 
pointed out with particularity in the claims anexed to and forming a part 
of this disclosure. For a better understanding of the invention, its 
operating advantages and specific objects attained by its use, reference 
should be had to the accompanying drawings and descriptive matter in which 
there are illustrated and described preferred embodiments of the 
invention.

DETAILED DESCRIPTION OF THE INVENTION 
In FIG. 1 a portion of the wheel hub assembly is shown in axial section and 
includes a wheel carrier 14 on which an outer bearing ring 13 of a wheel 
bearing 12 is secured. Inwardly of the outer bearing ring is an inner 
bearing ring 1 which has a radially outwardly extending flange-like 
extension 2 containing radially extending slots 7 having side surfaces 3. 
An internally ventilated brake disc 6 is secured either directly to the 
flange-like extension 2 by a screw connection or via a heat insulated 
cover disc 15. Accordingly, the combination of the slots 7 in the 
flange-like extension 2 and the cover provided by the radially inner 
portion of the brake disc 6 or the combination of the brake disc and the 
cover disc 15 define the cooling channels 7a for producing a ventilating 
effect in the wheel hub assembly. 
For the transmission of torque, the inner bearing ring 1 is connected to a 
rotary constant velocity joint 10. The joint 10 has an inner part and an 
outer part with the inner bearing ring 1 connected to the outer part. The 
inner part of the joint 10 is connected to a drive shaft 11 so that it 
rotates with the drive shaft. 
The inner bearing ring 1 has a central bore located radially inwardly of 
the flange-like extension 2 with a cover plate member 4 located in the 
central bore. The position of the cover plate member 4 within the bore can 
be seen in FIG. 2 with radially inwardly directed beads 5 formed in the 
cover plate member 4. As illustrated in FIG. 1, the cooling air flow 
enters the wheel hub assembly passing over the cover plate member 4 and 
entering the recesses formed by the beads 5. From these recesses, the air 
flow 8 passes through the cooling channels 7a defined between the 
flange-like extension 2 and the radially inner part of the brake disc 6, 
then passes over the outer bearing ring 13 and enters the apertures 9 in 
the radially outer part of the brake disc 6 and continues flowing 
outwardly over the internally ventilated brake disc. In addition, a part 
of the air flow passes between the brake disc 6 and the wheel carrier 14. 
In FIG. 2 the arrangement of the beads 5 in the cover cap or cover plate 
member 4 can be noted along with the arrangement of the flange-like 
extension 2 projecting radially outwardly from the inner bearing ring 1. 
While specific embodiments of the invention have been shown and described 
in detail to illustrate the application of the inventive principles, it 
will be understood that the invention may be embodied otherwise without 
departing from such principles.