Abstract:
A wheel bearing with an integrated constant velocity joint. The joint has a sheet-metal outer ring. Drive torque is transmitted from the outer ring of the constant velocity joint to the inner ring flange of a surrounding bearing by a tooth system. The tooth system is formed in the inner ring flange in such a way that it supports a wavelike outer contour of the outer ring of the constant velocity joint over a defined circumferential length section of the outer ring. The outer ring of the joint has tracks that mesh with the tooth system. The ends of the tracks are bent inward away from the tooth system.

Description:
FIELD OF THE INVENTION 
     The invention relates to a wheel bearing and a constant velocity joint, wherein the outer ring of the constant velocity joint is connected to the inner ring flange of the wheel bearing via a positive-locking connection to transmit torque from the constant velocity joint to the wheel bearing via this positive-locking connection. 
     BACKGROUND OF THE INVENTION 
     Integration of parts and an associated demand for lightweight construction are long known requirements in automobile construction. This also applies to the wheel bearing arrangement and to the attempt to integrate as many functions as possible into the wheel bearing arrangement from its surroundings. 
     Intensive effort has been made in integrating a constant velocity joint into a wheel bearing. A construction unit comprising a constant velocity joint and a wheel bearing is shown in DE 23 29 554 A1. The constant velocity joint is of a solid type of construction and is connected directly to the inner ring flange via a splined shaft profile. There are problems with this design. The solid construction of the outer ring of the constant velocity joint, in combination with the additional splined shaft profile, has a very large diameter. As a result, the wheel bearing lying on the outside has to be of large design. A further problem is that the tooth system extends over the entire axial length of the constant velocity joint. This prevents the outer ring of the constant velocity joint from yielding elastically in the face of the deformations which occur, due to the production tolerances in the tracks of the balls of the constant velocity joint. These constraining forces lead to additional undesirable heating in the constant velocity joint and to increased wear. 
     A constant velocity joint having opposed curved tracks is shown in DE 19831012 A1. This constant velocity joint has a flange for transmitting the torque. Since this constant velocity joint is designed as a sheet-metal part in a lightweight type of construction, it also requires a second small flange in order to achieve sufficient rigidity. This constant velocity joint with opposed tracks is therefore arranged next to the wheel bearing when it is fitted in place. 
     OBJECT OF THE INVENTION 
     The object of the invention is to provide a novel connection between the wheel bearing and the constant velocity joint, which connection meets the requirements for lightweight construction, is simple to produce and avoids constraining forces in the constant velocity joint. 
     DESCRIPTION OF THE INVENTION 
     A constant velocity joint is located inside the inner ring flange of the wheel bearing around the joint. According to the invention, there is a tooth system inside the inner ring flange of the outer surrounding wheel bearing, to which the torque is transmitted. The teeth of the tooth system extend axially across the inner ring flange, and have circumferentially leading and trailing tooth flanks. The tooth system is designed to mesh with the generally complementary contours of the sheet-metal outer ring of the constant velocity joint in defined sections so that those elements rotate together. These contours of the outer ring of the joint are obtained during the sheet-metal working. The tooth system does not come in contact in the end region of the track running radially inward. 
     There are surprising advantages of this tooth system located in the inner ring flange. 
     The outer contour of the outer ring of the constant velocity joint, which contour is obtained during the sheet-metal working for producing the tracks for the torque transmitting balls in the outer ring of the joint, is utilized for the transmission of the torque from the constant velocity joint to the wheel bearing. This provides a construction which is light weight and which has a small diameter because the additional tooth system shown in the prior art is dispensed with. Further production operations on the outer contour of the outer ring of the constant velocity joint are therefore unnecessary. 
     The flanges shown in the constant velocity joint in DE 198 31 012 A1 located on the outer ring of the constant velocity joint can be dispensed with. The task of the larger flange is to transmit the torque, and the task of the second flange is to increase the rigidity of the outer ring of the constant velocity joint. This necessary rigidity of the outer ring of the constant velocity joint is now replaced by the tooth system in the inner ring flange. In this case, the tooth system in the inner ring flange supports the outer ring of the constant velocity joint only at the flanks, i.e., the circumferentially leading and trailing surfaces, of the tracks of the outer ring of the joint. That end of each track which runs radially inward is exposed. There is the requisite elasticity of the outer ring of the constant velocity joint in order to keep all the torque transmitting ball bearings uniformly in the tracks in a pivoted constant velocity joint. The elasticity in this case is required in order to compensate for production tolerances in the constant velocity joint. 
     Due to the tooth system meshing in sections only between the wheel bearing and the constant velocity joint, heat transfer between these components is reduced. This has a positive effect on the service life, particularly of the wheel bearing. 
     The tooth system in the inner ring flange is simple to produce. This tooth system can be produced during cold or hot working for producing the inner ring flange. Broaching or milling processes are also suitable for producing this tooth system. Due to the design of the tooth system (e.g. straight or curved) in the inner ring flange, the position of the torque-transmitting area between the outer ring of the constant velocity joint and the tooth system of the inner ring joint can be freely selected. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows a sectional view of a wheel bearing with a constant velocity joint having tracks running in the same direction, 
     FIG. 2 shows a sectional view of an inner ring flange of a wheel bearing with a constant velocity joint having opposed tracks, 
     FIG. 3 shows a wheel flange with a tooth system and a constant velocity joint in a cross-sectional plan view on  3 — 3  in FIG. 2, 
     FIG. 4 shows an enlarged detail FIG. 3 showing of a tooth system between the inner ring flange and the outer ring of the constant velocity joint. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     FIG. 1 shows a wheel bearing unit with a constant velocity joint  10 . The wheel bearing unit shown has an outer ring flange  1 , two rows of rolling bodies  2  inside the outer ring flange, and two inner rings  3   a  and  3   b  inward of the rolling bodies, one inner ring for each row of rolling bodies. The inner rings are held together by the inner ring flange  4  inward of the inner rings. Wheel bearing variants in which one or both inner ring raceways of inner rings  3   a  and  3   b  are integrated directly in the inner ring flange are not shown, since the arrangement of the raceways either in individual inner rings or directly on the inner ring flange does not affect the invention. In the other Figures hereof, only the inner ring flange  4  of the wheel bearing is shown, since the latter inner ring flange contains the features of the invention. 
     There is a constant velocity joint  10  comprising an inner part  17 , a cage  16  outward of the part  17 , a row of torque transmitting bearing balls  15  and an outer ring  11 . The ring  11  is arranged inside the inner ring flange  4 . The outer ring  11  is designed as a sheet-metal part. It is provided with axially directed tracks  12  running in the same direction, and tracks in FIG. 1 are all inclined inward in one direction at region  12   a.    
     A tooth system  5  on the inside of the inner ring flange projects between the shaped portions of the tracks  12  of the outer ring  11  of the constant velocity joint  10 . The teeth of the tooth system are also axially extending. There is a bearing area  6  between the tooth flanks and the tooth system where the leading and trailing flanks of the tooth system and the flanks engage for torque transmission. An elastically movable region  12   a  of the track  12  to the lateral side of the row of balls  15  is not touched by the tooth system  5  as the region  12   a  turns inward radially. 
     The balls  15  of the constant velocity joint  10  move along the tracks in the outer ring of the joint and into the region  12   a  during cornering and/or during spring deflection of the wheel into this region. 
     FIG. 2 shows an inner ring flange  4  with a constant velocity joint having tracks  12  curved alternately in opposite directions. The tooth system  5  of the inner ring flange  4  bears on the outer contour of the outer ring  11  of the constant velocity joint  10  in the region  6  (wavelike, hatched). Because the individual track end regions  12   a ,  12   b  are curved alternately in opposite axial directions, the bearing region  6  is axially offset between two tracks lying side by side. Therefore the elastic region  12   a  or  12   b  of each track  12 , on which region the tooth system  5  of the inner ring flange does not bear, is likewise axially offset between two tracks. The inner part  17 , the cage  16  and the balls  15  of the constant velocity joint  10  are shown. 
     The inner ring flange  4  of the bearing, the outer ring  11  of the joint  10 , the inner part  17 , the balls  15  and the cage  16  of the constant velocity joint with opposed tracks are shown in FIG.  3  and FIG. 4 (in the enlarged detail). The sectional plane of the plan view is indicated at  3 — 3  in FIG.  2 . The interaction of the tooth system  5  of the inner ring flange  4  with the outer contour of the outer ring  11  of the constant velocity joint  10  is shown in these sectional views. The bearing region  6  of the tooth system on the generated surface of the track  12  is shown. In this case, the contour of the tooth system in the inner ring flange is adapted to the generated surface of the track  12 . The non-bearing regions  7  and  8  of the tooth system  5  are likewise shown. The task of these two non-bearing regions is not to load or deform the outer ring  11  of the constant velocity joint in regions which are not required for a positive-locking transmission of the torque. The flanks of the tracks  12  that are touched by the fit of the tooth system  5  totals less than 70% of the total length of the track in the circumferential direction. The opposed track  12  having the elastic region  12   b  is shown at a distance opposite the tooth system  5 . The cross-sectional plan view of FIG. 3, therefore, shows tracks which bear on the tooth system and tracks having an elastic region  12   b  which is located at a distance opposite the tooth system and these tracks alternate. 
     Although the present invention has been described in relation to particular embodiments thereof, many other variations and modifications and other uses will become apparent to those skilled in the art. It is preferred, therefore, that the present invention be limited not by the specific disclosure herein, but only by the appended claims.