Brake disk for a motor vehicle, motor vehicle, and method for operating a brake disk for a motor vehicle
The brake disc design with a gray cast iron base and hard material-coated friction layer, incorporating axial recesses and precise manufacturing methods, addresses the challenge of wear and appearance, achieving low wear and extended service life.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- BAYERISCHE MOTOREN WERKE AG
- Filing Date
- 2025-11-19
- Publication Date
- 2026-06-11
Smart Images
Figure DE2025101079_11062026_PF_FP_ABST
Abstract
Description
[0001] 24-2164
[0002] 1
[0003] Brake disc for a motor vehicle, motor vehicle and method for manufacturing a brake disc for a motor vehicle
[0004] The invention relates to a brake disc for a motor vehicle, a motor vehicle and a method for manufacturing a brake disc for a motor vehicle.
[0005] From DE 10 2006 060293 A1, a brake disc ring is known which has perforated bores perpendicular to the plane of friction surfaces. The perforated bores are cylindrical in shape. The brake disc ring is made of a fiber-reinforced ceramic material.
[0006] From DE 10 2012 106 304 A1, a brake disc with a friction surface is known that has areas with recesses. The recesses can vary in the circumferential direction. A through-hole is recessed in the friction surface of the brake disc, which opens into a cooling channel inside the brake disc. The brake disc is made of a ceramic composite material.
[0007] The object of the present invention is to provide a solution which enables the provision of a brake disc with a particularly long service life with at least one recess.
[0008] This problem is solved according to the invention by the subject matter of the independent claims. Further possible embodiments of the invention are disclosed in the dependent claims, the description, and the figures. Features, advantages, and 24-2164
[0009] Two possible embodiments set out in the description for one of the subject matter of the independent claims are to be regarded, at least analogously, as features, advantages and possible embodiments of the respective subject matter of the other independent claims as well as any possible combination of the subject matter of the independent claims, possibly in conjunction with one or more of the dependent claims.
[0010] The invention relates to a brake disc for a motor vehicle, in particular a car, and especially a passenger car. The brake disc can be part of a braking system of the motor vehicle. The braking system is a technical device of the motor vehicle designed to decelerate the motor vehicle and thus reduce its speed, in particular until the motor vehicle comes to a standstill. In addition to the brake disc, the braking system can include at least one brake pad, which is to be applied to a friction area of the brake disc for braking the motor vehicle. The friction area is thus designed to be brought into contact with the brake pad when the brake disc is used as intended in the motor vehicle for deceleration.To brake the motor vehicle, at least one brake pad is pressed against the friction area of the brake disc, whereby the motor vehicle is braked as a result of friction between the at least one brake pad and the brake disc.
[0011] The brake disc is designed to comprise a base body made of gray cast iron, which is coated with a layered system. In other words, the base body can be made of a gray cast iron alloy, specifically one of the alloys GG15 to GG35. Gray cast iron has a high melting point and particularly good heat storage and damping properties. Furthermore, gray cast iron is particularly easy to cast and machine. The layered system with which the base body is coated includes at least one friction layer, which in turn includes at least one hard material. The friction layer seals the brake disc on the outside and, when the brake disc is used as intended for braking the vehicle, can be brought into contact with at least one brake pad. 24-2164
[0012] 3
[0013] Hard materials are materials characterized by exceptionally high hardness. In particular, the hard material is an intermetallic phase, such as a metal carbide, or individual particles, as in a ceramic. Because at least one hard material is incorporated into the friction layer, the friction layer exhibits particularly low wear and, consequently, a particularly long service life. The brake disc is designed to have at least one recess located in the friction area. This recess can be, in particular, a perforation extending from one end face of the brake disc to the other, or a depression, especially in the form of a blind hole. The perforation extends completely through the brake disc in the axial direction.The recess or blind hole does not extend completely through the brake disc and instead terminates with its base within the disc. Due to the at least one hard material in the friction layer, the brake disc thus exhibits a particularly long service life, while simultaneously featuring at least one recess that extends completely through the disc in the axial direction. This at least one recess can therefore create a particularly sporty and dynamic appearance for the brake disc, while at the same time resulting in exceptionally low wear. The axial direction runs parallel to a longitudinal axis of the brake disc, which is preferably circular in shape.The brake disc is, in particular, a rotationally symmetric body whose axis of symmetry is simultaneously its central axis.
[0014] In a further possible embodiment of the invention, the friction layer comprises a carbide and / or corundum as a hard material. Carbides are binary chemical compounds consisting of an element and carbon. In particular, the carbide is a metallic carbide, such as tungsten carbide, titanium carbide, iron carbide, silicon carbide, or nickel carbide. These metal carbides exhibit particularly high hardness, which makes the friction layer especially robust and resistant to wear. Corundum is a relatively common mineral from the mineral class of oxides and hydroxides and exhibits very high hardness.
[0015] 4. Aluminum oxide is the oxygen compound of the chemical element aluminum and is also known as electrocorundum in technical fields.
[0016] In a further possible embodiment of the invention, the at least one recess is provided for in the base body prior to coating. This can be particularly well recognized by the distribution of the coating on the base body in relation to the recess. If the coating material of a coating of the layer system can thus be found at least partially within the recess, then it can be assumed that the at least one recess was provided in the base body before the base body was coated with the layer system. Providing the at least one recess in the base body enables particularly simple processing, since the base body is not reinforced with hard materials before coating with the layer system.As a result, there is particularly little tool wear when creating at least one recess, which in turn allows for particularly long service lives of tools used for manufacturing the brake disc.
[0017] In an alternative embodiment of the invention, the at least one recess is formed in the base body after it has been coated with at least one layer of the coating system, and in particular after it has been coated with the entire coating system. This means that the base body is first coated with at least one layer of the coating system, and then the at least one recess is formed in the coated base body. While this requires drilling through the hard-reinforced friction layer with a tool, it allows for particularly precise geometries of the at least one recess. Furthermore, residues of coating material within the recess can be effectively avoided.Subsequently introducing at least one recess into the coated base body enables precisely defined edges and radius transitions of the brake disc walls that define the recess. 24-2164.
[0018] 5
[0019] In a further possible embodiment of the invention, the layer system additionally comprises at least one intermediate layer arranged between the friction layer and the base body. This intermediate layer can serve as an adhesion promoter layer to ensure that the friction layer is held particularly securely to the base body and that differing mechanical properties, such as coefficients of thermal expansion, heat capacity, etc., between a material of the base body and a material of the friction layer can be particularly well compensated. It is possible that the at least one hard material is embedded only in the friction layer and not in the intermediate layer. By means of the intermediate layer, the risk of the friction layer detaching from the base body during operation can be kept particularly low.
[0020] In a further possible embodiment of the invention, a wall of the brake disc, which circumferentially delimits the recess, transitions into the respective end faces of the brake disc in the opening region with a chamfer and / or a rounded edge. The rounded edge is a rounded area with a predetermined radius or radius profile. The opening region is an end region of the recess where the recess opens into the surrounding area of the brake disc and thus transitions. It is provided that the chamfer and / or the rounded edge are present on the brake disc in the end region, and thus in the opening region, whereby the recess is circumferentially delimited by the chamfer or the rounded edge in the opening region. In other words, the cross-section of the recess widens in the opening region due to the chamfer or the rounded edge applied to the brake disc.By providing the chamfer or rounding, sharp edges on the end faces of the brake disc in the area of the recess opening can be effectively avoided. This significantly reduces the risk of critical stress on the brake disc in the area of the disc walls bordering the recess. Furthermore, the chamfer or rounding at the recess opening facilitates easy insertion of the recess into the brake disc due to the widening of the recess towards the respective end faces. 24-2164.
[0021] 6
[0022] The invention further relates to a motor vehicle with a brake disc as already described in connection with the brake disc according to the invention. It can be provided that a brake disc is provided for at least two wheels of the motor vehicle, in particular for each wheel of the motor vehicle. Furthermore, the motor vehicle can have at least one, in particular at least two, brake pads for each brake disc, wherein these two brake pads can be applied to opposite sides of the brake disc in the axial direction for braking. The use of the described brake disc with its particularly long service life in the motor vehicle means that the respective brake discs in the motor vehicle only need to be replaced very rarely.
[0023] The invention further relates to a method for manufacturing a brake disc for a motor vehicle. In the method, a base body comprising gray cast iron is coated with a layer system that includes at least one friction layer. This friction layer comprises at least one hard material. The method further provides that at least one recess—extending completely through the brake disc, particularly in the axial direction—is formed in the brake disc and is located in a friction area of the brake disc. This friction area is intended to be brought into contact with a brake pad for braking the motor vehicle when the brake disc is used as intended. The at least one recess can be formed, in particular, by drilling into the brake disc.In particular, it is provided that a brake disc is manufactured within the framework of the method, as already described in connection with the brake disc according to the invention. The at least one layer of the coating system can be applied in particular by laser cladding, which can also be referred to as laser metal deposition, laser coating, which can also be referred to as laser cladding, plasma coating, arc welding, cold gas spraying or high-speed flame spraying.
[0024] This process allows the production of a brake disc which, due to the inclusion of at least one hard material in the friction layer, exhibits particularly low wear and consequently a particularly long service life. 24-2164
[0025] 7
[0026] Furthermore, the brake disc has at least one recess, which gives the brake disc a particularly sporty appearance.
[0027] In a further possible embodiment of the invention, the at least one recess is provided for in the uncoated base body, and the base body is then coated with the coating system. For example, the at least one recess can be provided by drilling into the base body, and then the at least one layer of the coating system can be applied to the base body with the at least one recess. This makes it particularly easy to create the at least one recess in the brake disc, and wear on the tools used for creating the at least one perforation is particularly low, since the tool for creating the recess does not have to work through the friction layer comprising the at least one hard material.
[0028] In an alternative embodiment of the invention, the base body is coated with at least one layer of the coating system, and subsequently, the at least one recess is formed in the coated base body. In particular, it is provided that all layers of the coating system are applied to the base body, and subsequently, the at least one recess is formed in the coated base body. Because the base body is first provided with the at least one coating, and then the recess is formed in the coated base body, the recess formed in the coated base body exhibits particularly few deviations from predetermined dimensions for the recess.If the recess were first created in the base body and then at least one layer were applied to the base body, coating material of the applied layer could accumulate or be deposited in the recess, causing irregular edges and boundaries of the recess.
[0029] Further features of the invention may become apparent from the claims, the figures, and the description of the figures. The features and combinations of features mentioned above in the description, as well as the features and combinations of features shown below in the description of the figures and / or in the figures alone, are not only found in 24-2164.
[0030] 8 of the respective combinations specified, but can also be used in other combinations or on their own without leaving the scope of the invention.
[0031] The drawing shows in:
[0032] Fig. 1 shows a schematic sectional view of a brake disc base body with a recess, which is coated with a coating; and
[0033] Fig. 2 shows a schematic sectional view of the coated base body into which a perforation hole is inserted.
[0034] In the figures, identical and functionally equivalent elements are provided with the same reference symbols.
[0035] Figures 1 and 2 each show a brake disc 10 for a motor vehicle during a respective manufacturing step. The respective brake disc 10 is shown in partial view in each figure. The manufacturing step shown in Figure 1 produces the brake disc 10 in a first embodiment, while the manufacturing step shown in Figure 2 produces the brake disc 10 in a second embodiment that differs from the first. In both cases, a brake disc 10 is produced which comprises a base body 12 made of gray cast iron and a coating system 14 applied to the base body 12.
[0036] The layer system 14 applied to the base body 12 comprises at least one friction layer, in particular both a friction layer and an intermediate layer arranged between the base body 12 and the friction layer. The friction layer comprises at least one hard material. In the present design, the friction layer comprises a carbide and / or a corundum as the hard material. In a friction area 16, which, when the brake disc 10 is used as intended, is designed to be contacted by a brake pad of the vehicle for braking purposes, the brake disc 10 has at least one recess 18 in each of the embodiments. This recess 18 extends completely through the brake disc 10 in the axial direction A. In particular, the brake disc 10 has several recesses 18 in the friction area 16, which are 24-2164
[0037] 9 have a lateral distance from each other in a lateral direction perpendicular to the axial direction A. In the manufacture of the brake disc 10, it can be provided that the at least one recess 18 is introduced into the base body 12 before the base body 12 is coated, and subsequently the base body 12 is coated with the coating system 14, as can be seen in Fig. 1. In the process step shown in Fig. 1, it is provided that the base body 12 provided with the recess 18 is coated with the coating system 14 by laser cladding. In laser cladding, both a laser beam 22 and a powder jet 24 are directed onto a surface of the base body 12 to be coated by means of a nozzle 20. In laser cladding, the base body 12 is heated in a defocused manner by means of the laser beam 22 and thereby locally melted.The powder jet 24 comprises a gas stream, particularly of an inert gas, in which powder particles of the coating material are transported. At the heated area of the surface of the base body 12, the material powder melts and bonds with the base body 12.
[0038] In the brake disc 10 shown in Fig. 2, the base body 12 is first coated with the layer system 14, and then at least one recess 18 is formed in the brake disc 10. As shown in Fig. 2, the recess 18 can be formed in the coated base body 12 using a drilling tool 26. The at least one recess 18 can thus be formed in the base body 12 either before or after the hard material coating of the base body 12. Forming the recess 18 into the base body 12 before coating it makes it particularly easy to form the recess 18, since the base body 12 is not yet reinforced with hard material.As a result, tool wear for creating the at least one recess 18 can be kept particularly low, and a particularly long tool life can be achieved for the tool used to create the recess 18 in the base body 12. However, it is possible that coating residues may remain in the recess 18 due to the subsequent coating of the base body 12 provided with the recess 18. Furthermore, precisely defined edges and radii of the recess 18 may not be achieved. By creating the recess 18 in the base body 12 after it has been coated with the coating system 14 – regardless of whether the recess 18 is created before or after a grinding process, as described in 24-2164.
[0039] 10
[0040] Within the frame from which the friction layer of the coating system 14 is ground, a particularly precise hole geometry of the recess 18 can be achieved. Furthermore, particularly smooth transitions at chamfers and radii can be achieved. This allows irregularities in critically stressed areas of the recess 18, especially with respect to the radial direction, to be kept to a minimum. Subsequently creating the recess 18 in the base body 12 coated with the coating system 14 can lead to reduced tool life, since the drill bit 26 has to drill through the friction layer encompassing the hard material.
[0041] It is possible that in the respective opening areas 28, in which the recess 18 opens into the environment at its respective ends opposite each other in the axial direction A, particularly in the area of the respective end faces of the brake disc 10, the brake disc 10 has a chamfer and / or a radius in order to avoid sharp edges at the respective openings of the recess 18.
[0042] By coating the base body 12 with a hard material layer, in this case a friction layer comprising at least one hard material, abrasion and wear of the brake disc 10 can be kept particularly low, and a particularly long service life of the brake disc 10 can be achieved. To manufacture the brake disc 10, a one-, two-, or three-layer coating system 14 is applied to the disc-shaped base body 12, which is made in particular of a gray cast iron alloy of the GG15 to GG35 system. The coating system 14 applied to the base body 12 is characterized by extreme hardness and can therefore be prone to cracking, which can negatively affect the service life of the coating system 14. Therefore, brake discs coated with hard materials are usually manufactured without recesses 18 to prevent the introduction of notch-like cracks into the brake disc 10.
[0043] The described methods, in which the recess 18 is introduced into the brake disc 10 before or after coating the base body 12 with the coating system 14, make it possible to provide a brake disc 10 comprising a hard coating on a gray cast iron base body 12 with at least one recess 18. 4-2164
[0044] 11
[0045] Reference symbol list
[0046] 10 Brake disc 12 Base body
[0047] 14-shift system
[0048] 16 Friction area
[0049] 18 Exclusion
[0050] 20 Nozzle 22 Laser beam
[0051] 24 Powder jet
[0052] 26 Drilling tools
[0053] 28 Mouth area
[0054] A axial direction
Claims
24-2164 12 Patent claims 1. Brake disc (10) for a motor vehicle, comprising a base body (12) comprising a gray cast iron body, which is coated with a layer system (14) comprising at least one friction layer comprising at least one hard material, wherein the brake disc (10) has at least one recess (18) which is arranged in a friction area (16) of the brake disc (10), wherein the friction area (16) is intended to be brought into contact with a brake pad when the brake disc (10) is used as intended in the motor vehicle for braking the motor vehicle.
2. Brake disc (10) according to claim 1, characterized in that the friction layer comprises a carbide and / or a corundum as a hard material.
3. Brake disc (10) according to claim 1 or 2, characterized in that the at least one recess (18) has been introduced into the base body (12) prior to coating the base body (12).
4. Brake disc (10) according to claim 1 or 2, characterized in that the at least one recess (18) has been introduced into the base body (12) after coating the base body (12) with at least one layer of the coating system (14), in particular after coating the base body (12) with the entire coating system (14).
5. Brake disc (10) according to one of the preceding claims, characterized in that the layer system (14) additionally comprises at least one intermediate layer arranged between the friction layer and the base body (12).
6. Brake disc (10) according to one of the preceding claims, characterized in that 24-2164 13 a wall of the brake disc (10) circumferentially limiting the recess (18) transitions into a mouth area (28) of the recess (18) with a chamfer and / or a rounding into the respective end faces of the brake disc (10).
7. Motor vehicle with a brake disc (10) according to one of the preceding claims.
8. Method for manufacturing a brake disc (10) for a motor vehicle, in which a base body (12) comprising grey cast iron is coated with a layer system (14) comprising at least one friction layer comprising at least one hard material, and in which at least one recess (18) is provided in the brake disc (10), which is arranged in a friction area (16) of the brake disc (10), wherein the friction area (16) is provided to be brought into contact with a brake pad when the brake disc (10) is used as intended in the motor vehicle for braking the motor vehicle.
9. Method according to claim 8, characterized in that the at least one recess (18) is provided in the uncoated base body (12) and the base body (12) is then coated with the layer system (14).
10. Method according to claim 8, characterized in that the base body (12) is coated with at least one layer of the layer system (14) and subsequently the at least one recess (18) is introduced into the coated base body (12).