Brake disc for a braking device for a motor vehicle

Abstract

The invention relates to a brake disc (1) for a braking device for a motor vehicle, the brake disc comprising: a base disc (2) formed from a base disc material (3); and a coating (5) arranged on the base disc (2), the coating comprising at least one hard material which is different from the base disc material (3), wherein the brake disc (1) has at least one aperture (4), in particular a plurality of apertures (4), extending through the base disc (2) and the coating (5).

Description

[0001] Brake disc for a brake device for a motor vehicle

[0002] THINGS

[0003] The invention relates to a brake disc for a braking device for a motor vehicle, comprising a base disc formed from a base disc material and a coating arranged on the base disc, comprising at least one hard material different from the base disc material.

[0004] Brake discs for motor vehicle braking systems, comprising a base disc made of a base disc material, for example, a cast material, which is coated with a hard material, are generally known from the prior art. Such a coating with a hard material particularly reduces abrasion and wear of the brake disc and can therefore also contribute to increasing the service life of the brake disc.

[0005] While the advantages described above are achieved by coating the base disc with the hard material, they are accompanied by a significantly increased surface hardness compared to the base disc itself, i.e., compared to an uncoated brake disc. This results in localized changes to characteristic material properties such as thermal conductivity and heat capacity. Consequently, this increased hardness typically leads to a greater susceptibility to cracking or incipient cracking. This can negatively impact the coating's lifespan and, therefore, the overall lifespan of the brake disc, especially if the surface is damaged.

[0006] Therefore, brake discs of this type, which consist of a coated base disc made of a hard material, are designed without perforations, as this prevents the creation of additional points on the brake disc that could promote cracking or notching of the braking surface. Without such perforations, the brake disc and / or brake system are less able to clean the interface between the pad and the brake disc, resulting in less optimal braking performance in dirty or wet conditions.

[0007] The invention is based on the objective of providing an improved brake disc in comparison.

[0008] The problem is solved by a brake disc according to claim 1. The dependent claims relate to possible embodiments.

[0009] As described, the invention relates to a brake disc for a braking device for a motor vehicle. A braking device can be understood to be, in particular, the braking system of the motor vehicle. The brake disc comprises a base disc made of a base disc material. For example, a cast material can be used as the base disc material. The base disc of the brake disc is coated with a coating, or the coating is arranged on the base disc. The coating comprises at least one hard material that is different from the base disc material. The coating therefore forms the friction layer, or the friction surface or braking surface, which, for example, comes into contact with a brake pad of the braking device during a braking process. The friction surface or braking surface can therefore be reinforced by the coating with the hard material.

[0010] The invention is based on the finding that the brake disc has at least one opening, in particular a plurality of openings, extending through the base disc and coating. The term "opening" includes, for example, recesses that extend through a surface of the base disc to a cooling channel of the brake disc arranged between the two base discs. The term "opening" also includes indentations or depressions in the surface, such as dimples, dents, grooves, countersunk holes, and the like. The invention thus proposes that the base disc can be provided, for example, with the plurality of openings that act as perforations during the operation of the brake disc. Therefore, the term "opening" can also be understood as or replaced by the term "perforation bore" or "perforation" within the scope of this description.The brake disc assembly can, in particular, comprise two base discs connected to each other in the area of ​​a cooling channel located axially between them. The base discs can each have various perforations, especially at different locations. It is therefore proposed that the base disc provided with the perforations be coated with the coating, i.e., that the hard material be applied to or arranged on the base disc. The arrangement of the coating can include a direct application to the base disc material or an indirect application whereby at least one layer is arranged between the coating and the base disc. The coating can, in principle, comprise any identical and / or dissimilar layers.The described perforations offer not only improved cleaning of the interface between the pad and the brake disc and improved braking performance in dirty or wet conditions, but also a cooling effect and an improved sporty appearance.

[0011] Therefore, it is particularly important to avoid introducing perforations into the coating, especially subsequently, which could lead to cracking or induce "weak points" in the coating. Instead, the perforations are formed directly in the base plate, and the resulting geometry of the base plate is maintained by applying the coating. This means that the perforations are created in the coating itself during the coating process. As already described, the coating can include materials other than the hard material. In particular, the coating can comprise several different layer areas, which are applied to the base plate, for example, sequentially or in different process steps.

[0012] Advantageously, this provides a brake disc that has at least one perforation, and in particular a multitude of perforations, to positively influence or increase the braking performance of the brake disc or the braking system in general, even in the presence of dirt or moisture. Likewise, the at least one perforation allows for cleaning of the interface between the brake disc and the brake pad. Furthermore, the coating containing the hard material reinforces the braking surface and increases its hardness, thus achieving the benefits of reduced abrasion and wear, as well as increased service life.

[0013] In one embodiment of the brake disc, the base disc can be designed as a blank comprising at least one opening, onto which the coating is applied using a hybrid process. As already described, the coating is applied to the base disc material. The hybrid process therefore generally describes a manufacturing process using two different manufacturing technologies. For example, an intermediate layer and a friction layer can be produced using different manufacturing technologies. A first manufacturing technology (e.g., LMD - laser metal deposition) can be used to create the intermediate layer, and a second manufacturing technology (e.g., CGS - cold gas spray) can be used to create the friction layer. The base disc can be produced as a blank or as a finished part, i.e., as a complete part in one or more stages.to be provided for a further process step in which the coating is applied to the base disc.

[0014] The individual process steps for manufacturing the base disc and applying the coating therefore differ. For the purposes of this description, the base disc is generally understood to be the part of the brake disc on which the coating is applied. The coating is understood to be that part of the brake disc which includes at least the hard layer or the hard material. The brake disc therefore comprises the base disc and the coating.

[0015] In the hybrid process, the coating is applied to the base disc in such a way that at least one perforation, i.e., in particular the multitude of perforations provided in the base disc, remains unobstructed. Even after the coating is applied, the perforations in the base disc are therefore accessible or extend through the base disc and are not covered by the coating. The perforation thus extends either completely or incompletely through the braking surface, i.e., through the coating and through the base disc, or only incompletely through the base brake disc, i.e., through only one of the two base discs.

[0016] As described, any material can be used for the manufacture of the base disc, i.e., as the base disc material. In one embodiment of the brake disc, the base disc can be designed as a gray cast iron body, meaning that the base disc can be manufactured in a casting process.

[0017] In a previous embodiment, it was already described that the coating can comprise different layers, for example, at least one layer comprising the hard material. According to a further embodiment of the brake disc, the brake disc can have an intermediate layer, in particular made of a steel material, arranged between at least one hard layer of the coating containing the hard material and the base disc. This means that the coating contains the hard material in the at least one hard layer. The at least one intermediate layer is first applied to the provided base disc, and then the at least one hard layer of the coating containing the hard material is applied to the at least one intermediate layer.In principle, the intermediate layer can be understood as a component of the previously described coating, which also includes at least one hard material layer, or the intermediate layer can be understood as a separate layer. In both cases, the hard material layer and the intermediate layer can be applied separately. In any case, the coating includes the hard material layer or multiple hard material layers that form the friction surface of the brake disc, i.e., the layer that comes into contact with the brake pad.

[0018] As described, the intermediate layer can generally be arranged between the base material of the base disc and the hard material of the coating's hard layer. In particular, the intermediate layer can be applied directly to the base disc material. In one embodiment, the hard layer, which comprises the hard material, can be applied to the intermediate layer, particularly directly to the intermediate layer. In other words, the resulting layer sequence in the brake disc consists of the material of at least one intermediate layer being applied directly to the base disc material, and the hard material of at least one hard layer being applied directly to the intermediate layer.

[0019] This document proposes a multi-layer or two-layer system for coating the base disc, in which the intermediate layer is strategically positioned between the base disc material and the hard material to enable a defined application of the hard material layer. The applied intermediate layer, in particular, compensates for stress states between the hard material within the hard material layer and the base disc material. For this purpose, the hard material layer is applied to the intermediate layer, primarily by cold forming, with the intermediate layer providing a suitable substrate for the adhesion of the hard material. Stress states between the hard material and the base disc material are thus removed or eliminated from the brake disc by the intermediate layer. The intermediate layer therefore serves as a compensating layer between the hard material layer and the base disc.

[0020] In one embodiment of the brake disc, the intermediate layer can be applied to the base disc using laser metal deposition (LMD). In principle, in addition to laser metal deposition, other methods for applying the intermediate layer are also possible. The deposited material of the intermediate layer, for example, a steel alloy, can thus be deposited onto the base disc material and therefore form the surface onto which the hard material of the hard coating can be applied.

[0021] In one embodiment of the brake disc, the hard material layer of the coating can be applied by cold gas spraying (CGS) or by laser cladding. Cold gas spraying of the hard material for application to the intermediate layer has proven particularly advantageous.

[0022] In addition to the brake disc, the invention relates to a braking device for a motor vehicle, which includes a brake disc as previously described. The invention further relates to a motor vehicle, which includes such a braking device and / or a brake disc as previously described. The invention also relates to a method for manufacturing a brake disc for a braking device for a motor vehicle, comprising a base disc made of a base disc material and a coating arranged on the base disc, comprising at least one hard material different from the base disc material, wherein the coating is applied to the base disc, which has at least one opening, in particular a plurality of openings, wherein the opening extends through the base disc and the coating.

[0023] The described method can be used in particular to manufacture a previously described brake disc in all its details and with all its features.

[0024] All advantages, details, designs and / or features described in relation to the brake disc are fully transferable to the braking device, the motor vehicle and the process.

[0025] The invention is explained with reference to exemplary embodiments and the figures. The figures are schematic representations and show:

[0026] Fig. 1 shows a schematic representation of a brake disc according to an exemplary embodiment in axial view; and

[0027] Fig. 2 shows a schematic representation of a section of a brake disc according to an exemplary embodiment in sectional view.

[0028] Fig. 1 schematically shows a brake disc 1 for a motor vehicle's braking system in an axial view relative to an axis of rotation, which, for example, extends centrally into the plane of the drawing. The brake disc 1 has a base disc 2 made of a base disc material 3 (see Fig. 2). The brake disc 1 can also be understood as a friction ring. The brake disc 1 shown is, purely by way of example, designed as an internally cooled brake disc 1. This means that a cooling channel extends axially between the base discs 2. The following description can also be applied to brake discs 1 or friction rings that are not internally cooled. The base disc material 3 is, for example, a cast material, or the base disc 2 is manufactured using a gray cast iron process. The brake disc 1 has a plurality of openings 4 that penetrate the brake disc 1 axially.The openings extend axially through the base plates 2 and their base plate material 3. The number, size, arrangement in groups, and distribution of the openings 4 are merely exemplary and can be implemented in any other way. In particular, the arrangement of the openings 4 can be individually defined for each base plate 2, meaning that their positioning can differ from one another. The positions of the openings 4 can therefore differ within the base plates 2.

[0029] By way of example, Fig. 2 shows a section through the brake disc 1, whereby, for the sake of simplicity, a central segment of the brake disc 1 is hidden in the axial direction, so that only the surface areas of the brake disc 1 on both sides are shown. It can be seen that a coating 5 is applied to the base disc material 3 of the base discs 2. The coating 5 comprises at least one hard material layer 6 or any number of hard material layers 6, which comprise a hard material.

[0030] In principle, any suitable material, especially one that is sufficiently hard, can be used as a hard material. Specifically, the term "hard material" can be used. For example, the following materials can be used as hard materials: ceramics, nitrides, in particular boron nitride, titanium nitride, silicon nitride, titanium aluminum nitride, or (metal) carbides, in particular silicon carbide, boron carbide, tungsten carbide, vanadium carbide, titanium carbide, tantalum carbide, or oxides, in particular aluminum oxide, zirconium dioxide, which may optionally be formed as a metal-matrix composite or embedded in a (metal) matrix, or formed as aggregates in a metallic matrix.

[0031] An intermediate layer 7, which can be made of a steel material, is arranged between the hard layer 6 of the coating 5 of each base disc 2 or the base disc material 3. For the manufacture of the brake disc 1, the base disc 2(s) and the connecting structure between them, which in particular forms the cooling channel, are provided from the base disc material 3, wherein the base disc 2 has the openings 4, or each of the base discs 2 has openings 4. For example, the base disc 2(s) and the connecting structure can be made of gray cast iron having the openings 4. The two base discs 2 and the connecting structure can be considered and manufactured as a common friction ring.The intermediate layer 7 of the coating 5 is then applied to the base discs 2. For example, the intermediate layer 7 is applied to the base disc material 3 of the base discs 2 by means of laser cladding.

[0032] Subsequently, the hard layer 6 of the coating 5 is applied to the intermediate layer 7, specifically by means of cold gas spraying. This causes the coating 5, in particular the hard layer 6 and the intermediate layer 7, to assume the surface shape of the base disc 2, so that they also have perforations 4. Specifically, it is therefore not necessary to perforate a subsequently applied hard layer 6 or to introduce perforations into the hard layer 6. Furthermore, the intermediate layer 7 ensures particularly good adhesion of the hard layer 6 and compensates for stresses between the base disc 2 and the hard layer 6. The intermediate layer 7 thus prevents the hard layer 6 from cracking, even during operation of the brake disc 1, i.e., under temperature and force.the openings 4 do not form predetermined breaking points for cracks in the hard material layer 6.

[0033] The advantages, details, and features described with respect to the illustrated embodiments, and in particular with respect to the figures, can be combined, interchanged, and transferred to one another as desired. The method described herein can be used to manufacture the brake disc 1 as described. The description is further transferable to a brake device comprising a brake disc 1 or to a motor vehicle comprising at least one such brake device and / or at least one brake disc 1. [List of reference symbols]

[0034] 1 brake disc

[0035] 2 Base plate 3 Base plate material

[0036] 4 Breakthrough

[0037] 5 coating

[0038] 6 Hard layer

[0039] 7 Intermediate shift

Claims

REQUIREMENTS 1. Brake disc (1) for a brake device for a motor vehicle, comprising a base disc (2) formed from a base disc material (3) and a coating (5) arranged on the base disc (2), comprising at least one hard material different from the base disc material (3), characterized in that the brake disc (1) has at least one opening (4), in particular a plurality of openings (4) extending through the base disc (2) and the coating (5).

2. Brake disc (1) according to claim 1 , characterized in that the base disc (2) is designed as a blank comprising at least one opening (4) onto which the coating (5) is applied in a hybrid process.

3. Brake disc (1) according to claim 1 or 2, characterized in that the base disc (2) is designed as a grey cast iron body.

4. Brake disc (1) according to one of the preceding claims, characterized in that the brake disc (1) has an intermediate layer (7), in particular made of a steel material, arranged between at least one hard material layer (6) of the coating (5) comprising the hard material and the base disc (2).

5. Brake disc (1) according to claim 4, characterized in that the hard material layer (6) of the coating (5) comprising the hard material is applied to the intermediate layer (7).

6. Brake disc (1) according to claim 4 or 5, characterized in that the intermediate layer (7) is applied to the base disc (2) by means of laser cladding.

7. Brake disc (1) according to one of the preceding claims, characterized in that the hard material layer (6) of the coating (5) is applied by means of cold gas spraying or by means of laser cladding.

8. Braking device for a motor vehicle, comprising a brake disc (1) according to any one of the preceding claims.

9. Motor vehicle, comprising a braking device according to the preceding claim. Claim and / or a brake disc (1) according to any one of claims 1 to 7.

10. Method for manufacturing a brake disc (1) for a brake device for a motor vehicle, comprising a base disc (2) formed from a base disc material (3) and a coating (5) arranged on the base disc (2), comprising at least one hard material different from the base disc material (3), characterized in that the coating (5) is applied to the base disc (2), which has at least one opening (4), in particular a plurality of openings (4), wherein the opening (4) extends through the base disc (2) and the coating (5).

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