Brake disk

[0002] (1) Field of the Invention

[0003] The invention relates to a brake disk for disk brakes, in particular of land vehicles, with a friction ring received by a support section formed by, for example, a portion of a wheel hub, wherein the support section has an out-of-round outer formation on which the friction ring is seated torsion-tight with a centric opening of complementary out-of-round inner formation.

[0004] (2) State of Prior Art

[0005] Such a brake disk is known from EP-B-0 642 632. Therein is proposed a wheel hub and such a brake disk configuration for a vehicle wheel, which comprises a hub section borne rotatably on an axle end by a bearing device, a brake disk support connected with the hub section, a brake disk rotatably fastened on the brake disk support and a disk-form support, which is fastened on the hub by a screw-type connection and to which a wheel rim can be screwed. The brake disk support is developed radially outside of the screw-type connection unitarily with the disk-form support, wherein the brake disk support does not have a circular outer formation on which a brake disk with an opening having a congruent inner formation is rotatably fastened. Thereby a wheel hub and brake disk configuration is to be provided in which a common screw-type or welding connection for the brake disk and the brake disk support can be avoided. The known configuration is in particular disadvantageous since high fabrication expenditures, high accuracy of fit in the region of the non-circular formations and an additional securement of the brake disk on the brake disk support against axial displacement must be provided.

[0006] It is the task of the present invention to propose a brake disk of the above described type in which, with simple means, a nonuniform heat distribution in the friction ring, and thus a distortion of the friction ring, so-called “canopying-out” of the friction ring, at the temperatures occurring during braking and heat transfer onto the wheel bearing are avoided. With the invention, in particular, on the other hand, undesirable wear of the friction ring and stress fractures in the friction ring are to be avoided and, on the other hand, the shortening of the service life of the lubrication oil, present in the wheel bearing and/or bearing parts of synthetic material, are to be counteracted.

[0007] This task is essentially solved according to the invention in the case of a brake disk of the above described type by the friction ring, and preferable also the support section, comprising cast metal with the friction ring being cast onto the prefabricated support section.

[0008] It was found that the cast connection according to the invention between the friction ring and the support section, in particular if the latter also comprises cast metal, is ruptured upon first heating of the brake disk, and thus during the first braking process, such that the friction ring is separated from the support section. In this way a brake disk which, relative to the prior art is simple in structure and mounting, and in which, due to the separation gap generated between the friction disk and the support section, excessive stress, and thus stress fractures, in the friction ring, even at high braking power, for example in the field of trucks, are avoided. Moreover, due to the separation gap formed, heat flow from the friction ring to the support section, and thus the wheel bearing, is prevented.

[0009] With different constructions the support section can be formed, for example, by a pot-like hub section of the brake disk itself, a bearing hub on which a wheel flange can be fastened, or by a unitary wheel flange hub, wherein the last variant is especially cost-effective. In case the friction ring is changed, the wheel hub (possibly with the bearing) can also be exchanged, such that a new manufacturer's warranty can be issued for the entire assembly. If the support section is formed by a unitary wheel flange hub, a separate wheel flange screw-type connection is omitted, with corresponding weight saving.

[0010] When using a brake disk with a separate pot-like hub section, the hub section can comprise, for example, a high-strength metal material and the friction ring a specific high-temperature disk material.

[0011] The out-of-round formation of the support section is formed according to a special inventive concept by ribs or protuberances, preferably force-framing, protuberances. The number of ribs or protuberances can be varied according to the technical requirements. Here, as well as in the case with a general out-of-round shape, no special fabrication precision is required since, due to the casting of the friction ring onto the out-of-round shape, for example in the form of ribs or protuberances, irregularities are per force compensated. Force-framing protuberances have the advantage that they extend on all sides into the opening margin of the friction ring, such that not only the reliable transmission of torques but also a securement against axial displacement of the friction ring on the support section is ensured.

[0012] In further development of the inventive concept, the support section in the region of the out-of-round formation can be equipped with holes or slits for air circulation. If the friction ring is structured such that it is solid, the holes or slits can be omitted.

[0013] Further goals, characteristics, advantages and application feasibilities of the present invention are evident in the following description of embodiment examples in conjunction with the drawing. All described and/or graphically represented characteristics, by themselves or in any combination form the subject matter of the invention, independently of their recapitulation in individual claims or their reference back.

[0014] In the drawings

[0015] FIGS. 1aand 1b, in radial section and in a partially sectioned view, show a brake disk comprising the invention according to a first embodiment with a pot-like bearing section,

[0016] FIGS. 2aand 2b, also in radial section and in partially sectioned view, show a brake disk comprising the invention according to a different embodiment, wherein the brake disk is received on a bearing hub, and

[0017] FIG. 3 is a representation similar to that of FIG. 2aof a further embodiment of the invention, wherein the brake disk is received on a unitary wheel flange hub.

[0018] FIG. 4 is a view similar to that of FIG. 1a, but showing a solid friction ring in accordance with a second embodiment.

[0019] An internally ventilated brake disk 1 according to FIGS. 1aand 1b, which is intended for disk brakes of, in particular, of land vehicles, has a pot-like hub section 6, which, on the one hand, is adapted for a screw-type connection with a (not shown) wheel hub and, on the other hand, is adapted for connection with a friction ring 4 having an opening 5. Alternatively, as shown in FIG. 4, a solid friction ring 4′ may be used in place of the ventilated friction ring 4.

[0020] For the purpose of connection with the wheel hub, the pot-like hub section 6, at its end facing away from the friction ring 4, comprises a radial inner flange 12 with holes 13 distributed over its periphery for receiving axially parallel connection bolts. On a support section 3 facing the friction ring 4 the hub section 6 has force-framing protuberances 10. The friction ring 4 is cast on the region of the support section 3 of the prefabricated pot-like hub section 6. The hub section 6 of the brake disk 1, as well as the friction ring 4, can comprise cast metal. The support section 3 is further provided with holes 11 or slits 11′, which improve the air circulation in the internally ventilated friction ring 4. In the event a solid friction ring 4 is used, the holes 11 or slits 11′ can be omitted.

[0021] In the embodiment of FIGS. 2aand 2bthe brake disk 1 is a mere planar friction ring 4, which is cast onto the support section 3 of a bearing hub 7. Toward the outside the wheel flange 14 of wheel hub 2 can adjoin the bearing hub 7 via bolts 15.

[0022] In the embodiment depicted in FIG. 3 the support section 3, onto which the friction ring 4 is cast such that it partially flows around the force-framing protuberances 10, is a unitary wheel flange hub 9, which serves for direct mounting of the vehicle wheel.

[0023] The cast connection according to the invention between the friction ring 4 or 4′ and the support section 3 is ruptured upon first heating of the brake disk 1, and thus during the first braking process, the friction ring 4 or 4′ is separated from the support section 3. Specifically, the friction ring 4 or 4′ comprises cast metal cast onto the support section 3 to form a cast connection between the friction ring 4 or 4′ and the support section 3, with the cast connection between the friction ring 4 or 4′ and the support section 3 being such that upon an initial heating of the brake disk 1 the cast connection becomes ruptured and the friction ring 4 or 4′ becomes separated from the support section 3.