Abstract:
A brake disk includes a disk chamber and a one-piece component made up of a friction ring having connecting links, a supporting ring and extensions developed on the supporting ring. In order to prevent cracking caused by tensile stresses, which may occur during the temperature increase in response to braking, recesses are developed at the transition between the supporting ring and the disk chamber.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a brake disk, e.g., a ventilated brake disk having a friction ring and a supporting structure connected to the friction ring via connecting links, e.g., a disk chamber. 
     2. Description of Related Art 
     A ventilated brake disk is known from published German patent application document DE 43 32 951 A1, which has a friction ring and a supporting structure connected to the friction ring using connecting links. The connecting links are especially developed as pins, bolts or the like, and are positioned over the circumference of the supporting structure. The connecting links project into recesses in the circumferential wall of the friction ring. In the case of larger braking torques, there is a danger that, based on the free length of the connecting links, that is, based on the distance between supporting structure and friction ring, the connecting links, might bend and, in the extreme case, detach from their seat. 
     Furthermore, a brake disk is known from published German patent application document DE 10 2007 05 43 93 A1, in which the friction ring and the disk chamber are also produced of different materials, and connected using connecting links, especially pins. These known brake disks are characterized by the number of individual parts and the processing steps connected with this, and the great technical effort involved. Consequently, these brake disks are relatively costly to produce. In addition, the connecting locations of the different components each mean points of attack for corrosion and other damage. 
     BRIEF SUMMARY OF THE INVENTION 
     By contrast, the brake disk according to the present invention has the advantage that the number of components of the brake disk is reduced. In this connection, the various operations are also reduced. Supporting ring, connecting links and friction ring are able to be produced in one operation. During the casting process of the disk chamber, that is made of aluminum, the friction ring may be cast integrally with it. This reduces the costs of the various operations, and provides a possibility of producing a so-called “low-cost brake disk”. Because of the special positioning of the bevels of the studs of the supporting ring, in response to the shrinking of the disk chamber made of aluminum and cast integrally, a firm connection is created, so that a transfer of the torque is enabled that is free of play. Furthermore, the leakproofness of the contact locations is also ensured, since, on account of the bevels of the studs, no gap is created during the solidification process, into which corrosion-promoting media such as salt water could penetrate. In a further operation, recesses may simply be introduced in the transition range between the supporting ring and the disk chamber, so that no tensional cracks or tensional breaks are able to occur in response to the temperature increase due to braking. The temperature expansions created in the brake disks and the supporting ring may be balanced in a simple manner via the recesses. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a top view of a brake disk. 
         FIG. 2  shows a detailed representation of the transitional range between disk chamber and friction ring. 
         FIG. 3  shows the friction ring as an integral component with the supporting ring. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In  FIG. 1 ,  10  designates a brake disk made up of a disk chamber  11  and a friction ring  12 . A disk chamber  11  is fastened to a hub of a vehicle, in a manner not shown here, the screws for fastening it extending through boreholes  13  of disk chamber  11 . Friction ring  12  is made up of two friction ring halves  12   a  and  12   b , which are connected to each other by a plurality of crosspieces elements  17  that are distributed over the circumference and run particularly in the radial direction, so that a ventilated brake disk is created. Friction ring  12  is situated on disk chamber  11  with the aid of connecting elements  16  of a supporting ring  20  and extensions  21 ,  22 . One integral component is represented by connecting elements  16 , extensions  21 ,  22  and friction ring  12 . This component is able to be produced in one operation. It is possible to produce the two friction ring halves  12   a  and  12   b  using the crosspieces  17  in one operation. In another operation, supporting ring  20  is produced having connecting elements  16  and extensions  21 ,  22 , in this operation friction ring  12  being also integrally cast onto connecting elements  16 . The component thus produced is illustrated in  FIG. 3 . Supporting ring  20 , connecting elements  16  and extensions  21 ,  22  are made of cast iron, as is friction ring  12 . By contrast, disk chamber  11  is made of aluminum. During the casting of disk chamber  11 , friction ring  12  and its supporting ring  20 , i.e. the component as shown in  FIG. 3 , is integrally cast onto disk chamber  11 . In order to ensure the sealing of the mold for disk chamber  11 , the axial surfaces of the supporting ring  20 , that is, the end faces, are processed. In order to ensure the integral casting of supporting ring  20  and friction ring  12  onto disk chamber  11 , extensions  21 ,  22  are developed on supporting ring  20 . Extensions  21 ,  22  are developed at regular intervals at the inner circumference of supporting ring  20 . In each case two extensions  21  are present one after the other, and then one extension  22 . Extension  22  is developed approximately centrally between two successive extensions  21 . Extension  22  has walls  24  that run approximately perpendicularly. Extensions  21  have a slanting wall  25  on the sides facing each other. These walls  25  may represent an undercut, for example. Walls  26  of extensions  21  facing extensions  22  are developed to be perpendicular. They have approximately the shape of walls  24  of extensions  22 . Moreover, extensions  22  are situated about centrally between two connecting elements  16 . The two extensions  21  are also located between two connecting elements  16 , extensions  21  being located as close as possible to the area of the starting points of connecting elements  16 . Extensions  22  are used to transfer the braking torque from supporting ring  20  and from friction ring  12  to disk chamber  11 . It should be noted that the braking torque is transferred from friction ring  12  to supporting ring  20  with the aid of connecting elements  16 . Based on their slanting walls  25 , extensions  21  make it possible, after the integral casting of disk chamber  11  onto supporting ring  20 , during the cooling of the material, i.e. the aluminum, that shrinking of the aluminum of disk chamber  11  onto the cast iron of supporting ring  20  takes place. This prevents the radial relative motion of disk chamber  11  and supporting ring  20  with respect to each other. Consequently, a transfer of torque, that is free of play, is ensured from supporting ring  20  to disk chamber  11 . Slanting walls  25  of extensions  21 , in this context, are developed and aligned to the shrinking process in such a way that during the shrinking of the aluminum, during its solidification, no gaps are able to be created, into which corrosion-promoting media, such as salt water, are able to penetrate during the operation of the brake. Furthermore, as may be seen in  FIG. 2 , recesses  30  are developed between extensions  21 . These recesses  30  are developed in an additional operation, after the integral casting of disk chamber  11  onto supporting ring  20 , and after the complete cooling of the aluminum. These recesses  30  may be produced as bores, for example. These recesses  30  have the task of balancing thermally caused, different expansions between the material of disk chamber  11  and the material of supporting ring  20 . Heat is created in friction ring  12  during braking, which is also transferred to supporting ring  20  via connecting elements  16 . In the process, friction ring  12  expands somewhat. If supporting ring  20  could not expand because of recesses  30 , tensile stresses would occur which could lead to the cracking of supporting ring  20 .