WO2023166142A1

WO2023166142A1 - Friction ring for a brake disc of a disc brake of a vehicle, and method for producing a friction ring for a brake disc of a disc brake of a vehicle

Info

Publication number: WO2023166142A1
Application number: PCT/EP2023/055365
Authority: WO
Inventors: Bernhard Träger; Torsten Langer; Oliver ALTMANN
Original assignee: Bergmann Automotive GmbH
Priority date: 2022-03-03
Filing date: 2023-03-02
Publication date: 2023-09-07
Also published as: DE102022105045A1

Abstract

The invention relates to a friction ring (1) for a brake disc of a disc brake (2), preferably of a vehicle (3), said friction ring (1) having: a first ring section (10) with an end-face first brake surface (10a), a second ring section (11) which is arranged at a distance to the first ring section (10) in an axial direction (A) and which comprises an end-face second brake surface (11a), and a ring connection section (12) which connects the first ring section (10) to the second ring section (11). The invention is characterized in that the friction ring (1) is designed as a single-piece rotocast part.

Description

FRICTION RING FOR A BRAKE DISC OF A VEHICLE DISC BRAKE AND METHOD OF MANUFACTURING A FRICTION RING FOR A BRAKE DISC OF A VEHICLE DISC BRAKE

The invention relates to a friction ring for a brake disk of a disk brake of a vehicle. Furthermore, the invention relates to a brake disc for a disc brake of a vehicle. Furthermore, the invention relates to a disc brake for a vehicle and a vehicle. Furthermore, the invention relates to the use of a friction ring for a brake disk of a disk brake of a vehicle. Finally, the invention relates to a method for producing a friction ring for a brake disk of a disk brake of a vehicle.

A vehicle is, for example, a motorcycle, a passenger vehicle, a truck or a trailer. A vehicle is in particular also a bicycle. Furthermore, a vehicle can, for example, also be a rail-bound vehicle, an airplane, a gondola or the like.

Disc brakes belong to the type of friction brakes. The disc brake has a brake disc. The brake disk includes a friction ring which is connected to a flange in a torque-proof manner. The friction ring is fastened to a hub, for example a wheel hub, which is designed for fastening a wheel or a rim, via the flange. Furthermore, the disc brake includes a opposite Friction ring fixed brake caliper, which partially encloses the brake disc, in particular the friction ring. The brake caliper is usually permanently connected to a chassis of the vehicle. A brake pad and brake linings are usually arranged within the brake caliper. If the disc brake is actuated, the brake linings are in contact with the brake disc or the friction ring of the brake disc, so that a vehicle is braked. If the disc brake is not actuated, the brake pads are not in contact with the disc brake or the friction ring.

Thus, by means of the disk brake for a vehicle, for example, a rotational movement of the wheel or the rim of the vehicle relative to the chassis of the vehicle can be delayed or even completely prevented (“emergency braking”). A disc brake serves to decelerate the vehicle. When braking, the vehicle's kinetic energy is converted into thermal energy, which must be dissipated to the environment for the disc brake to have an efficient braking effect. The suitability of the disc brake to dissipate the thermal energy on convection elements by means of thermal radiation to the environment essentially depends on the mass of the disc brake, the material properties and the component geometry.

It is known to produce friction rings and brake disks by casting methods such as sand casting methods in single casting in the vertical or horizontal method. These manufacturing processes are labor intensive and time consuming; for example, cores are to be produced using the core shooting process in order to achieve the desired geometry of the friction ring or brake disc. However, the core shooting process requires the use of substances that are harmful to health and the environment. In particular, friction rings or brake discs produced using the sand casting process must then be subjected to a complex cleaning and blasting process before they can be machined. Furthermore, friction rings or brake discs produced in this way generally have non-uniform mechanical properties and material properties in the radial direction. For example, the hardness and microstructure of friction rings manufactured using the sand casting process are uneven in the radial direction and cannot be specifically adjusted in order to ensure uniform wear over the service life of a disc brake. Furthermore, uneven material densities and inaccuracies in the core shooting process can lead to imbalances. In particular, this manufacturing process can lead to changes in the surface zone structure, structural deformities and chilling as a result of small casting allowances and excessively rapid cooling. Finally, normalization annealing is sometimes required to eliminate process-related stresses to dismantle This is particularly necessary with ventilated disc brakes in order to relieve structural weaknesses at the transitions between webs and friction cross sections. This is not only time-consuming, but also requires energy resources and also pollutes the environment.

It is therefore an object of the present invention, a friction ring for a brake disc of a vehicle disc brake, a brake disc for a vehicle disc brake, a vehicle, a use of a friction ring for a brake disc of a vehicle disc brake, a method for producing a friction ring for a To provide a brake disc for a disc brake of a vehicle and a method for producing a brake disc for a disc brake of a vehicle that eliminates or reduces one or more of the aforementioned disadvantages.

According to one aspect, the object of claim 1 is solved by a friction ring for a brake disk of a disk brake of a vehicle.

The friction ring according to the invention is designed to be connected torque-proof to a flange unit for operation in the disc brake. The friction ring and the flange unit connected to it together form the brake disc of the disc brake. In the operating state, the brake disk is usually fastened in a torque-proof manner to a hub, in particular a wheel hub, of a vehicle. In particular, the friction ring is designed to be in engagement with brake pads for braking a vehicle. When braking, there is frictional contact between the brake pads and the friction ring. In particular, the friction ring is therefore to be designed to be low-wear with regard to braking and to be designed in such a way that it efficiently dissipates the thermal energy induced during braking in a particularly advantageous manner for effective braking.

When the brake disc is in operation, it is partially surrounded by a fixed brake caliper. The brake caliper includes a brake pad and brake pads. If the brake pad is actuated, usually hydraulically actuated, the brake pads are pressed against the friction ring in an axial direction. As a result, the rotating brake disc is slowed down in relation to the fixed brake caliper.

As explained above, in the operating state the friction ring is fastened in a torque-proof manner to a hub, in particular a wheel hub, by means of a flange unit. Thus, the friction ring rotates with the hub about an axis of rotation when the disc brake is not actuated. Thus, in the operating state, the friction ring is preferably arranged essentially coaxially to the axis of rotation.

The friction ring has a first ring section and a second ring section. The first ring section has a first braking surface on the face side. The second ring section has a second braking surface on the face side. The first and second ring portions are spaced apart in an axial direction. In particular, the first and second braking surfaces are arranged spaced apart from one another in the axial direction. The first and second braking surfaces are oriented such that the first and second braking surfaces extend substantially orthogonal to the axial direction. The first and second braking surfaces are arranged such that they face away from each other. As a result, the brake pads of the disc brake can come into contact with the first and second braking surface in the operating state. Thus, it is understood that the friction ring extends in the axial direction between the first braking surface and the second braking surface.

The first and second ring sections are ring-shaped. It is to be understood in particular that the first and second ring sections, starting from the first and second braking surfaces, correspond to a partial extension of the friction ring in the axial direction. In particular, the ring-shaped first and second ring sections form a closed ring in the circumferential direction.

Furthermore, it is provided that the friction ring according to the invention has a ring connection section which connects the first ring section to the second ring section. In particular, it is to be understood that the ring connecting portion integrally forms the friction ring together with the first and second ring portions.

The first and second ring sections and the ring connecting section each extend in the axial direction with a section width. It may be preferred that the section widths of the first ring section and/or the second ring section and/or the ring connection section are the same. In particular, it can be preferred that the section width of the ring connection section differs from the section width of the first and second ring section, the section width of the first and second ring section preferably being the same. The first and/or second ring section preferably has a section width of at least 1 mm and at most 20 mm. Furthermore, it is preferable that the ring connection section has a section width of at least 0 mm and at most 15 mm. It is particularly preferred that the brake disk has a width of at least 2 mm and at most 50 mm.

The friction ring preferably has an annular disk inner peripheral surface and an annular disk outer peripheral surface. Preferably, the annular disk inner peripheral surface and/or the annular disk outer peripheral surface extends essentially orthogonally to the first and/or second braking surface. In particular, the friction ring extends in a radial direction, orthogonal to the axial direction, between the inner circumferential surface of the annular disk in the radial direction and the outer circumferential surface of the annular disk lying outside in the radial direction compared to the inner peripheral surface of the annular disk with a ring height. The annular disk inner peripheral surface has an inner diameter and the annular disk inner peripheral surface has an outer diameter that is larger than the inner diameter.

It can be preferred that the first and/or second ring section and/or the ring connecting section each have a ring disk inner peripheral surface whose inner diameters are identical. Furthermore, it can be preferred that the first and/or the second ring section and/or the ring connecting section each have a ring disk inner peripheral surface whose inner diameters are different. In particular, it can be preferred that the first and/or second ring section each have an inner peripheral surface of the annular disk with identical inner diameters and the ring connecting section has an inner peripheral surface of the annular disk with an inner diameter that differs from the inner diameter of the inner peripheral surface of the annular disk of the first and second ring sections. In particular, it is preferred that the inner diameter of the inner peripheral surface of the ring disk of the ring connecting section is larger than the inner diameter of the inner peripheral surface of the annular disk of the first and/or second ring section.

It can be preferred that the first and/or the second ring section and/or the ring connecting section each have a ring disk outer peripheral surface whose outside diameters are identical. Furthermore, it can be preferred that the first and/or second ring section and/or the ring connecting section each have a ring disk outer peripheral surface whose outer diameters are different. In particular, it can be preferred that the first and/or the second ring section each have a ring disk outer peripheral surface with an identical outer diameter and the ring connecting portion has an annular disk outer peripheral surface with an outer diameter which is different from the outer diameter of the annular disk outer peripheral surface of the first and second ring sections. In particular, it is preferred that the outside diameter of the annular disk outer peripheral surface of the ring connecting section is smaller than the outside diameter of the annular disk outer peripheral surface of the first and/or second ring section.

In particular, it is preferred that the outer diameter of the annular disk outer peripheral surface is larger than the inner diameter of the annular disk inner peripheral surface.

The friction ring according to the invention is designed as a one-piece centrifugally cast part. The friction ring designed as a one-piece centrifugally cast part is in particular a friction ring that is produced in a centrifugal casting process. To produce this centrifugally cast part, a molten centrifugally cast mass can be fed to a permanent mold in a preferred manner according to the method described below. In particular, it should be understood that the friction ring designed as a one-piece centrifugally cast part can be produced by cutting to length a tubular and/or cylindrical centrifugally cast blank produced using the centrifugally cast method. In particular, the friction ring designed as a one-piece centrifugally cast part is not to be understood as meaning a friction ring produced by welding the ring sections to the ring connecting section or a similar product.

The friction ring according to the invention has the advantage that, depending on the tempering of the mold and the speed in the radial direction of the friction ring, a desired microstructure and hardness profile can be set in a targeted manner. In particular, this has the advantage that the friction ring has a uniform material density in the radial direction and in the circumferential direction and therefore has no imbalances. In this respect, when using friction rings produced in this way before assembly on the vehicle, imbalances do not have to be removed in a time-consuming manner. In particular, the molds with which the friction ring is produced can be temperature-controlled in a targeted manner so that normalization annealing is no longer necessary. Furthermore, in the case of friction rings produced in this way, the time-consuming post-processing steps of cleaning and blasting are preferably eliminated.

Furthermore, a friction ring produced as a centrifugally cast part has the advantage that comparatively light slags, pores, inclusions, etc. during the liquid phase by the acting centrifugal forces, which push the heavier cast iron to the outer diameter, are transported inwards in the radial direction and are deposited on the inner diameter or in the inner machining allowance of a cast blank of the friction ring.

A friction ring produced by means of centrifugal casting is a low-stress and homogeneous cast ring with high material quality and the best possible strength as well as few casting defects. Due to the process, such a friction ring is therefore free of pores, inclusions or slag. In addition, the cooling process after centrifugal casting can be controlled in a targeted manner, so that a friction ring produced in this way is free from cooling stresses. Furthermore, hardness and structure can be adjusted by a controlled cooling process depending on customer requirements. Furthermore, a centrifugally cast friction ring already has a high balance quality, which is additionally increased by the subsequent mechanical processing. By specifically adjusting the hardness and structure, the best possible wear parallelism can be guaranteed over the entire service life of the disc brake.

For further advantages, design variants and design details of the friction ring according to the invention and its developments, reference is also made to the following description of the corresponding features and developments of the brake disc, the disc brake, the vehicle and the method for producing a friction ring.

According to a preferred development of the friction ring, it is provided that the first braking surface and the second braking surface are produced using the centrifugal casting method. In particular, according to a preferred development of the friction ring, it is provided that the first braking surface and the second braking surface are produced by turning and/or milling.

According to a further preferred development of the friction ring, it is provided that the ring connecting section extends between a connecting ring inner peripheral surface lying on the inside in a radial direction and an outer connecting ring peripheral surface lying on the outside in the radial direction, and has a plurality of through bores which extend from the connecting ring inner peripheral surface to the connecting ring outer peripheral surface. The through-holes serve in particular to cool the friction ring during braking. It can therefore be understood that the through-holes increase the surface area of the friction ring in order to better dissipate the heat induced during braking. Thus, the through bores have the particular effect that the required braking power of the friction rings is maintained during braking or that the disc brake with such a friction ring does not fail during braking.

The through bores can be made in the ring connecting section in a simple manner by machining, in particular by drilling. A friction ring produced in this way has the particular advantage that no sand cores have to be produced for its production, as is the case, for example, in the sand casting process in order to produce these desired through-holes. Furthermore, this procedure has the advantage that the friction ring according to the invention cools down evenly and the need for stress-relief annealing is therefore eliminated, but at least it is less pronounced. In particular, the reject rate is lower with friction rings produced in this way, since the stresses that occur in sand-cast friction rings in the area of the thin webs at the transition to the solid ring sections and, in the worst case, lead to cracking, do not occur in the friction rings according to the invention. In particular, the use of the friction rings according to the invention therefore also leads to safer disc brakes during operation and thus enables safer participation in traffic.

In particular, the friction ring in this preferred embodiment has the advantage that through-holes can be made in the friction rings exclusively depending on the function, without the cooling behavior or the stresses induced by the cooling of a friction ring produced with sand cores in the sand casting process having to be taken into account in the design of the friction ring. Through this preferred configuration of the friction ring, through-holes can thus be introduced into the friction ring independently of the preceding centrifugal casting step.

Furthermore, this has the effect that no expensive sand cores have to be produced, which have to be positioned in the sand mold in a complex process. Rather, the through-holes can be provided in the friction ring with a significantly higher accuracy than was previously the case with friction rings due to the friction ring in this preferred embodiment. Furthermore, according to a preferred embodiment of the friction ring, it is provided that the through bores extend essentially in the radial direction. Additionally or alternatively, according to this preferred development, it is provided that the through bores have a circular cross section. Furthermore, according to this preferred development, it is additionally or alternatively provided that the through bores are of cylindrical design. A friction ring designed in this way has the particular advantage that it can be produced easily, quickly and inexpensively using conventional tools, for example drills. In particular, it can also be preferred to design the through bores in such a way that they have a square cross section, for example. A square cross-section can be created, for example, by broaching.

Furthermore, according to a preferred development of the friction ring, it is provided that the through bores have a bore wall whose surface has an average roughness value Ra of at most 50 μm, 25 μm, 12.5 μm, 10 μm, 7.5 μm, 5 μm, 2 5 pm or 1 pm. A friction ring designed in this way has the advantage that the average surface roughness of the bore wall of the through bores is lower compared to the conventionally produced friction rings. This improves the flow behavior of the air located in the through bores for cooling the friction ring. A friction ring according to this preferred embodiment can therefore enable significantly improved heat dissipation, although the surface of the friction ring relevant for cooling can be smaller in this preferred embodiment compared to friction rings produced with sand cores in the sand casting process.

According to a further preferred development of the friction ring, it is provided that the adjacently arranged through-holes are arranged at a distance from one another in a circumferential direction, the distance between the adjacently arranged through-holes being constant or different. A friction ring with through bores arranged equidistantly spaced apart in the circumferential direction can be produced comparatively inexpensively. A friction ring with through bores arranged equidistantly spaced apart in the circumferential direction enables a targeted setting of a desired cooling profile of the friction ring.

According to a further preferred embodiment of the friction ring, it is provided that the through bores are arranged equidistantly spaced in the circumferential direction and/or the through bores are arranged in one row or in multiple rows. According to this preferred embodiment, the friction ring depending on the required Cooling performance cost-effectively have a row or rows of through holes. Particularly in the case of a friction ring with through bores arranged in multiple rows, the rows are arranged at a distance from one another in the axial direction. In particular, it can also be preferred that the through-holes of the respective rows are offset from one another in the circumferential direction. It can also be preferred that the through bores in the case of several rows are arranged offset relative to one another only in the axial direction, that is to say are arranged essentially parallel to one another.

Furthermore, according to a preferred development of the friction ring, it is provided that the through bores have a bore diameter and the distance between through bores arranged adjacent in the circumferential direction corresponds at least to the bore diameter. Additionally or alternatively, according to this preferred development, it is provided that the ring connecting section has a ring width in the axial direction that is larger than the bore diameter or smaller than the bore diameter or corresponds to the bore diameter. Depending on the size of the bore diameter in relation to the ring width or the section widths, the required cooling capacity can be specifically tailored to the application.

According to a further preferred development of the friction ring, it is provided that the ring connecting section between adjacently arranged through bores is in each case designed as a connecting web which connects the first and second ring sections to one another.

Furthermore, according to a preferred development of the friction ring, it is provided that several perforation bores extend between the first and second braking surface. Preferably, the perforation holes on the surface have average roughness values of at most 50 μm, 25 μm, 12.5 μm, 10 μm, 7.5 μm, 5 μm, 2.5 μm or 1 μm.

According to a further preferred embodiment of the friction ring, it is provided that the perforation bores extend between the first braking surface and the second braking surface, preferably essentially in the axial direction, and/or have a circular cross-section, and/or are cylindrical, and/or such are arranged such that they extend through the connecting webs of the ring connecting section, and/or are arranged in such a way that they pass through the through bores of the ring connecting section extend, and / or are arranged spaced apart in the circumferential direction at least at a distance that is greater than the bore diameter.

Furthermore, according to a preferred embodiment of the friction ring, it is provided that the friction ring consists of gray cast iron, in particular of a lamellar gray cast iron or nodular cast iron.

Furthermore, according to a preferred development of the friction ring, it is provided that the first ring section and/or the second ring section extends between an inner circumferential surface of the annular disk, which is on the inside in the radial direction, and an outer circumferential surface of the annular disk, which is on the outside in the radial direction amounts.

Additionally or alternatively, according to this preferred development of the friction ring, it is provided that the ring connecting section extends between the connecting ring inner peripheral surface and the connecting ring outer peripheral surface in the radial direction with a connecting ring height, the connecting ring height preferably being at least 5 mm and a maximum of 300 mm, with the connecting ring height preferably being smaller than that washer height.

Furthermore, according to a preferred embodiment of the friction ring, it is provided that a degree of hardness decreases in the radial direction or is constant, starting from an outer ring peripheral surface lying on the outside in the radial direction to an inner ring peripheral surface lying on the inside in relation to the ring outer peripheral surface in the radial direction. The degree of hardness is given, for example, in Brinell tungsten carbide hardness. This specification is also known as Brinell hardness. For example, the test method can be carried out with a tungsten carbide ball with a diameter of 5 mm and a test force of 7.355 kN with an exposure time of 10 s to 15 s. A friction ring designed in this way has the advantage that the friction ring enables a particularly strong and reliable braking effect, especially in the outer area, in which comparatively large braking torques can act during operation. In particular, this makes it possible to use the friction ring over a comparatively long service life. In addition to a comparatively above-average friction loss and heat transfer, the development of fine dust is minimized. Furthermore, according to a preferred development of the friction ring, it is provided that the friction ring has an annular inner peripheral area, which extends starting from the ring inner peripheral surface in the direction of the ring outer peripheral surface, and an annular outer peripheral area, which starting from the ring outer peripheral surface extends in the direction of the ring inner peripheral surface, and one has an annular central peripheral portion extending between the annular inner peripheral portion and the annular outer peripheral portion, wherein the degree of hardness in the annular central peripheral portion is lower than in the annular inner peripheral portion and/or the annular outer peripheral portion. This enables a special design of the friction ring, which can be individually matched to the friction partner in order to enable a reliable and long-lasting braking effect.

Furthermore, according to a preferred development of the friction ring, it is provided that the degree of hardness is between 100 hardness Brinell tungsten carbide and 250 hardness Brinell tungsten carbide, in particular between 150 hardness Brinell tungsten carbide and 225 hardness Brinell tungsten carbide. Preferably, the degree of hardness is in the range of

Ring inner peripheral surface in a range of 170 hardness Brinell tungsten carbide. Alternatively or additionally, it is preferred that the degree of hardness in the range of

Ring outer peripheral surface is in a range of 200 hardness Brinell tungsten carbide. A particularly durable and reliable braking effect of the friction rings was observed in this specified area.

Furthermore, according to a preferred embodiment of the friction ring, it is provided that the friction ring has a structure comprising pearlite, in particular lamellar pearlite, steadite and ferrite as structural components. The microstructure components perlite, in particular lamellar perlite, and/or steadite are preferably distributed essentially uniformly or homogeneously between the inner peripheral surface of the ring and the outer peripheral surface of the ring. A particularly advantageous and long-lasting braking effect can be achieved with a friction ring that has a structure with these components. In particular, it was observed that the tensile strength is many times higher than that of known friction rings. In some cases it has been observed that the tensile strength is at least 40% higher than with previously known friction rings. In addition to a comparatively above-average friction loss and heat transfer, the development of fine dust is minimized.

In particular, according to one embodiment of the friction ring, it is provided that the

Structural component perlite between 70% and 100%, in particular between 80% and 95% %, particularly preferably between 90% and 95%, and/or the steadite structural component is between 0% and 20%, in particular between 5% and 15%, particularly preferably between 5% and 10%, and/or the structural component Ferrite is between 0% and 30%, in particular between 0% and 5%, particularly preferably between 0% and 1%. A friction ring that has a structure with structural components in the range mentioned enables high, reliable and long-lasting braking performance.

Finally, according to a further preferred embodiment of the friction ring, it is provided that the structural component ferrite decreases in the radial direction starting from an outer ring peripheral surface lying on the outside in the radial direction to an inner ring peripheral surface lying on the inside in relation to the ring outer peripheral surface in the radial direction and/or the structural component ferrite is provided predominantly adjacent to the ring outer peripheral surface .

According to a further aspect, the object is achieved by a brake disc for a disc brake of a vehicle according to claim 19.

The brake disc has a flange unit, which is designed for attachment to a hub, in particular a wheel hub, and a previously described friction ring, which is connected torque-proof to the flange unit, the flange unit preferably consisting of a light metal, in particular aluminum, or this essentially includes.

For further advantages, design variants and design details of the brake disc according to the invention and the developments, reference is also made to the preceding description of the corresponding features and developments of the friction ring and to the following description of the corresponding features and developments of the disc brake and the vehicle and the method.

According to a further aspect, the object is achieved by a disc brake for a vehicle according to claim 20.

The disc brake has a previously described friction ring and/or a previously described brake disc. Furthermore, the disc brake has a brake caliper, which is arranged on the friction ring and/or the brake disc, with brake pads which are designed to delay a rotational movement of the friction ring and/or the brake disc relative to a chassis. For further advantages, design variants and design details of the disc brake according to the invention and the developments, reference is also made to the preceding description of the corresponding features and developments of the friction ring and the brake disc and to the following description of the corresponding features and developments of the vehicle and the method.

According to a further aspect, the object is achieved by a vehicle according to claim 21.

The vehicle has a friction ring as described above and/or a brake disc as described above and/or a disc brake as described above.

For further advantages, design variants and design details of the vehicle according to the invention and the developments, reference is also made to the previous description of the corresponding features and developments of the friction ring, the brake disc, the disc brake and to the following description of the corresponding features and developments of the method.

According to a further aspect, the object of claim 22 is achieved by using a previously described friction ring for a brake disk of a disk brake of a vehicle, the vehicle being in particular a passenger vehicle and/or a commercial vehicle and/or a two-wheeler.

For further advantages, design variants and design details of the use according to the invention, reference is also made to the preceding description of the corresponding features and developments of the friction ring, the brake disc, the disc brake and to the following description of the corresponding features and developments of the method.

According to a further aspect, the object of claim 23 is achieved by a method for producing a friction ring for a brake disk of a disk brake of a vehicle. In particular, the object of claim 23 is achieved by a method for producing a previously described friction ring for a brake disc of a disc brake of a vehicle. For this purpose, the friction ring has a first ring section with a first braking surface formed on the front side and a second ring section arranged at a distance from the first ring section in an axial direction with a second braking surface formed on the front side. Furthermore, the friction ring has a ring connection section which connects the first ring section to the second ring section. In particular, the present friction ring has features of the friction ring described above.

The procedure for solving the task comprises several steps:

The method includes providing a centrifugal casting machine with a chill mold for centrifugal casting, the chill mold being in particular cylindrical, preferably tubular. Furthermore, the method includes the step of applying a sizing to an inside of the chill mold. Furthermore, it is provided that the method involves feeding a molten centrifugal casting mass, which is in particular a molten gray cast iron, particularly preferably a molten lamellar gray cast iron, into the chill mold coated with the wash. This is followed by centrifugal casting of the supplied centrifugal mass. The centrifugally cast centrifugal mass is then cooled, so that it solidifies to form a tubular cast blank. The cooled tubular cast blank is then sandblasted and the brake disc is produced with the first ring section with the first braking surface arranged on the front side and the second ring section with the second braking surface arranged on the front side by mechanical processing, in particular by turning or milling.

It may be preferred to design the mold in such a way that the friction rings can be produced individually in the mold using the centrifugal casting process. In particular, it can be preferred that the chill mold is designed to produce a single friction ring or a plurality of friction rings individually in the centrifugal casting process. In the case of the isolated production of a friction ring, it should be understood in particular that friction rings produced in this way already have a basic shape of a friction ring intended for operation after centrifugal casting. In particular, with this type of isolated production of a friction ring, it is not necessary to cut individual friction ring blanks from the cast blank.

For further advantages, design variants and design details of the method according to the invention and the further developments, reference is also made to the previous one Referenced description of the corresponding features and developments of the friction ring, the brake disc, the disc brake and the vehicle.

According to a preferred development of the method, it is provided that the step of producing the brake disk includes sawing off a brake disk blank from the cooled cast blank.

Furthermore, it is preferably additionally or alternatively provided that the method comprises the following steps:

- Introducing through-holes, in particular in a radial direction, preferably in the ring connecting section, and/or

- Introducing a plurality of cooling channels, which extend between the first and second braking surface, in particular through connecting webs of the ring connecting section, and/or

- Introduction of a groove or grooves in the first and / or second braking surface.

According to a preferred development of the method, it is provided that the centrifugal casting step takes place at a speed in a range between 400 revolutions per minute and 1,500 revolutions per minute over a centrifugal time in a range between 1000 seconds and 3000 seconds. This allows the production of a friction ring that allows a comparatively high friction effect with a long service life of the friction ring.

Furthermore, according to a preferred development of the method, it is provided that the cooling step takes place over a cooling time in a range between 10 seconds and 180 seconds.

Furthermore, according to a preferred embodiment of the method, it is provided that the step of applying the sizing layer on the inside of the chill mold comprises: Application of the size layer at a speed in a range between 400 revolutions per minute and 1,800 revolutions per minute over a first application time in a range between 10 seconds and 50 seconds.

According to a further preferred development of the method, it is provided that the centrifugal casting mass to be supplied is heated in a furnace to a temperature in the range between 1350° C. and 1490° C. and/or in a pan to a temperature in the range between 1350° C. and 1490° C was heated.

The methods according to the invention and their possible developments have features or method steps that make them particularly suitable for being used for a friction ring according to the invention and/or a brake disc according to the invention and/or a disc brake according to the invention and/or a vehicle according to the invention as well as the respective developments.

For further advantages, design variants and design details of these further aspects and their possible developments, reference is also made to the previously given description of the corresponding features and developments of the friction ring, the brake disc, the disc brake and the vehicle.

Preferred embodiments of the invention are explained by way of example with reference to the accompanying figures. Show it:

Fig. 1: a schematic side view of an exemplary embodiment of a

Vehicle with a disc brake in a preferred embodiment;

Fig. 2: a schematic view of a preferred embodiment of a

Friction ring of the preferred embodiment of the disc brake provided in FIG. 1;

FIG. 3: a schematic top view of the preferred ones provided in FIG

Embodiment of the friction ring;

FIG. 4: a schematic side view of the preferred ones provided in FIG

Embodiment of the friction ring; FIG. 5 shows a schematic sectional view of the friction ring shown schematically in a side view in FIG. 4; and

Fig. 6: a schematic block diagram of a preferred embodiment of a

Method for producing a friction ring for a brake disc of a disc brake of a vehicle for producing a disc brake 2 shown above with a friction ring 1 shown above.

Figure 1 is a schematic side view of an exemplary embodiment of a truck 3 with a disc brake 2 in a preferred embodiment. The disk brake 2 has a brake disk with a friction ring, as is described in detail below by way of example with reference to FIGS. For the operation of the disc brake 2, the friction ring is connected torque-proof to a flange. Via the flange, the brake disc is in turn connected in a torque-proof manner to a wheel hub, to which a wheel or a rim of the vehicle 3 is fastened. In order to achieve a braking effect, the disc brake 2 comprises a brake caliper which, during operation of the disc brake, is arranged on the chassis of the vehicle 3 in a stationary manner in relation to the brake disc. The brake caliper is arranged in such a way that it partially encloses the brake disc 1 . In order to brake the vehicle 3, the brake caliper has a brake pad for actuating brake pads and the brake pads, which rest against the brake disc when the brakes are actuated, so that the vehicle is braked. If the disc brake is not actuated, the brake pads are not in contact with the disc brake or the friction ring. As a rule, the brake pads are then arranged at a distance from the brake disc. Thus, for example, a rotational movement of the wheel or the rim of the vehicle relative to a chassis of the vehicle can be delayed or even completely prevented by means of the disk brake for a vehicle.

FIG. 2 shows a schematic view of a preferred embodiment of a friction ring 1 made of gray cast iron of the preferred embodiment of the disc brake 2 provided in FIG. On the one hand, this is a first ring section 10 with a first braking surface 10a formed on the front side, and on the other hand a second ring section 11, which forms a second braking surface 11a on the front side. It can be seen that the first and second ring sections 10, 11 are aligned coaxially with one another and are arranged at a distance from one another in the axial direction. The first and second ring sections 10, 11 are aligned with one another in such a way that the first and second braking surface 10a, 11a extend orthogonally to the axial direction A and face away from each other, ie face outwards. Due to this arrangement and orientation, the first and second braking surface 10a, 11a can come into contact with the brake pads arranged in the brake caliper when the vehicle is braking during operation of the disc brake.

The first and second ring sections 10, 11 are connected to each other by a ring connecting section 12. FIG. According to the invention it is provided that the first and second ring section 10, 11 and the ring connecting section 12 are formed in one piece as a centrifugally cast part. This means in particular that the first and second ring section 10, 11 and the ring connecting section 12 in one

Centrifugal casting are made. In particular, this means that the individual sections 10, 11, 12 are not welded to one another or connected to one another in a positive or non-positive manner. However, it should be understood that the friction ring 1, which is designed as a one-piece centrifugally cast part, can be cut to length from a tubular cast blank produced by centrifugal casting and/or can be partially post-processed mechanically.

It can be seen that the friction ring 1 extends in the axial direction between the first and second braking surfaces 10a, 11a over a ring width. It is also clear that the first and second ring sections 10, 11 and the ring connecting section 12 each extend over a section width. In this preferred embodiment, it is provided that the section width of the first and second ring sections 10, 11 is smaller than the section width of the ring connecting section 12. Alternatively, of course, it can also be preferred that the section width of the first and second ring sections 10, 11 is larger than the Section width of the ring connection section 12.

It can also be seen that the friction ring extends in a radial direction R, orthogonal to the axial direction A, between an inner peripheral surface of the annular disk and an outer peripheral surface of the annular disk, with the outer peripheral surface of the annular disk being located on the outside in relation to the inner peripheral surface of the annular disk in radial direction R. In this respect, the inner peripheral surface of the annular disk has an inner diameter that is smaller than an outer diameter of the outer peripheral surface of the annular disk. FIG. 2 makes it clear that the individual sections 10, 11, 12 of the friction ring 1 can have annular disk inner peripheral surfaces with different inside diameters and annular disk outer peripheral surface with different outside diameters. In the one shown in Figure 2 In a preferred embodiment, it is provided that the inner diameter of the annular disk inner peripheral surfaces of the two ring sections 10, 11 and the outer diameter of the annular disk outer peripheral surfaces of the two ring sections 10, 11 are identical. It is also provided that the outside diameter of the ring disk outer peripheral surface of the ring connecting section 12 is smaller than the outside diameter of the first and second ring section 10, 11. The inside diameter of the ring disk inner peripheral surface of the ring connecting section 12 is larger than the inside diameter of the ring disk inner peripheral surfaces of the first and second ring section 10, 11. This results in an annular circumferential groove in the ring connecting section 12 both on the outside and on the inside. This is also illustrated by the schematic sectional view in Figure 5.

The annular connecting section 12 has a plurality of through bores 15 which extend in a cylindrical shape with a circular cross section between the annular disk inner peripheral surface and the annular disk outer peripheral surface for cooling purposes. In the present preferred exemplary embodiment, it is provided that the through bores 15 extend essentially in the radial direction R. The through holes are produced by machining the centrifugally cast part. In this case, average roughness values R _a of a maximum of 50 μm are preferably generated on the surface of the bore walls of the through bores 15, but smaller average roughness values are also possible, as was explained in relation to the general description. In the present case, the through bores were made in the friction ring 1 or in its ring connecting section 12 in such a way that they are arranged equidistantly from one another in the circumferential direction U. Due to the constant cross section in the radial direction, however, it is to be understood that the distance between the through bores 15 arranged adjacent in the circumferential direction decreases, starting from the outer peripheral surface of the annular disk in the direction of the inner peripheral surface of the annular disk. This is illustrated in a greatly simplified, schematic sectional view of the friction ring 1 shown in FIG. 2. In any case, it can be seen that this arrangement of the through bores of the ring connecting section 12 forms connecting webs 16 between adjacent through bores 15, which connect the first and second ring sections to one another. This becomes particularly clear in FIG.

Of course, the through-holes can also have a different shape and arrangement. For example, it may be preferred that the cross section of the through bores 15 between the ring disk outer peripheral surface and the Ring disc inner peripheral surface varies, in particular decreases or increases. In a preferred embodiment, it can also be preferred that the through-holes are formed in a curved manner between the outer peripheral surface of the annular disk and the inner peripheral surface of the annular disk. Curved through holes can be produced by milling, for example.

In the preferred embodiment of the friction ring 1 shown in FIG. 2, a single-row arrangement of the through bores 15 is provided. It can also be preferred to provide friction rings with through bores arranged in multiple rows. In this case, the friction rings can have a plurality of rows of through bores, which are arranged in the axial direction A and are offset in parallel. In addition or as an alternative, it can also be preferred that the multiple rows of through bores 15 are arranged offset in relation to one another in the circumferential direction U.

In the present preferred embodiment, it is preferable that the through holes 15 have a hole diameter D substantially equal to the section width of the ring connection section 12 . In an alternative preferred embodiment, it may be preferable for the bore diameter D to be smaller than the section width of the ring connection section 12. Alternatively, of course, it may also be preferable for the bore diameter D to be larger than the section width of the ring connection section 12.

The preferred embodiment of the friction ring 1 illustrated in FIG. 2 also has a plurality of perforation bores 17 which extend between the first and second braking surfaces 10a, 11a. In the present preferred development, it is provided that the perforation bores 17 extend essentially in the axial direction as cylindrical channels with a circular cross section. On the one hand, these serve to absorb dirt and, in a wet environment, interrupt a thin film of liquid that then forms on the braking surfaces. As a result, the necessary braking performance can be guaranteed despite dirt and moisture. It is to be understood that, in addition to or as an alternative to the perforation bores, grooves, for example milled spiral grooves or the like, can also be provided, which also have the function of interrupting a possible liquid film and absorbing dirt.

Figure 6 shows a schematic block diagram of a preferred embodiment of a method 1000 for producing the friction ring 1 described above for Brake disk of the disk brake 2 of the vehicle shown schematically in FIG.

To produce the friction ring 1, the method includes the following steps:

The method 1000 includes providing 1010 a centrifugal casting machine with a permanent mold for centrifugal casting, the permanent mold being in particular cylindrical, preferably tubular. Furthermore, the method 1000 includes the step of applying 1020 a coating to an inside of the chill mold. Provision is also made for the method 1000 to supply 1030 a melted centrifugal casting compound, which is in particular a melted gray cast iron, particularly preferably a melted lamellar gray cast iron, into the chill mold coated with the wash. This is followed by centrifugal casting 1040 of the supplied centrifugal mass. A cooling 1050 of the centrifugally cast centrifugal mass is then provided, so that it solidifies into a tubular cast blank. The cooled tubular cast blank is then blasted 1060 and the brake disc is produced 1070 with the first ring section with the first braking surface arranged on the front side and the second ring section with the second braking surface arranged on the front side by mechanical processing, in particular by turning or milling. Furthermore, it is possible to introduce 1080 through bores 15, in particular in a radial direction R, preferably in the ring connecting section 12, as well as to introduce 1090 several perforation bores 17, which are located between the first and second braking surface 10a, 11a, in particular through connecting webs 16 of the ring connecting section 12, extend, provided.

Reference character list

1 friction ring

2 disc brake

3 vehicle

10 first ring section

10a first braking surface

11 second ring section

11 a second braking surface

12 ring connection section

13 ring inner peripheral surface

14 ring outer peripheral surface

15 through holes

15a surface

16 connecting bridge

17 perforation holes

A axial direction

D bore diameter

R radial direction

U circumferential direction

Claims

Claims Friction ring (1) for a brake disc of a disc brake (2), preferably of a vehicle (3), the friction ring (1) having:

- a first ring section (10) with a first braking surface (10a) formed on the front side and a second ring section (11) arranged at a distance from the first ring section (10) in an axial direction (A) and having a second braking surface (11a) formed on the front side,

- a ring connecting portion (12) connecting the first ring portion (10) to the second ring portion (11), characterized in that

- The friction ring (1) is designed as a one-piece centrifugally cast part. Friction ring (1) according to the preceding claim 1, wherein the

Ring connecting section (12) extends between a connecting ring inner peripheral surface (13) lying on the inside in a radial direction (R) and a connecting ring outer peripheral surface (14) lying on the outside in the radial direction (R), and has a plurality of through holes (15) extending from the connecting ring inner peripheral surface (13) to the

Connecting ring outer peripheral surface (14) extend. Friction ring (1) according to the preceding claim 2, wherein the through bores (15)

- extend substantially in the radial direction (R), and/or

- have a circular cross-section, and/or

- Are cylindrical. Friction ring (1) according to one of the preceding claims 2-3, wherein the through bores (15) have a bore wall whose surface (15a) has an average roughness Ra of maximum 50 pm, 25 pm, 12.5 pm, 10 pm, 7.5 pm, 5 pm, 2.5 pm or 1 pm.

5. Friction ring (1) according to one of the preceding claims 1-4, wherein the adjacently arranged through bores (15) are arranged at a distance from one another in a circumferential direction (U), the distance between the adjacently arranged through bores (15) being constant or is different.

6. friction ring (1) according to any one of the preceding claims 1-5, wherein

- the through bores (15) are arranged equidistantly spaced in the circumferential direction (U), and/or

- The through-holes (15) are arranged in one or more rows.

7. Friction ring (1) according to any one of the preceding claims 1-6, wherein the through bores (15) have a bore diameter (D) and

- the distance between through bores (15) arranged adjacent in the circumferential direction (U) corresponds at least to the bore diameter (D), and/or

- the ring connecting section (12) has a ring width in the axial direction (A) which is larger than the bore diameter (D) or smaller than the bore diameter (D) or corresponds to the bore diameter (D).

8. Friction ring (1) according to one of the preceding claims 1-7, wherein the ring connecting section (12) between adjacently arranged through bores (15) is in each case designed as a connecting web (16) which connects the first and second ring sections (10, 11) to one another .

9. Friction ring (1) according to any one of the preceding claims 1-8, wherein a plurality of perforation bores (17) extend between the first and second braking surface (10a, 11a). 10. Friction ring (1) according to the preceding claim 9, wherein the perforation bores (17)

- extend between the first braking surface (10a) and the second braking surface (11a), preferably essentially in the axial direction, and/or

- have a circular cross-section, and/or

- Are cylindrical, and / or

- are arranged in such a way that they extend through the connecting webs (16) of the ring connecting section (12), and/or

- are arranged in such a way that they extend through the through bores (15) of the ring connecting section (12), and/or

- Are arranged spaced apart from one another in the circumferential direction (U) at least by a distance which is greater than the bore diameter (D).

11. Friction ring (1) according to one of the preceding claims 1-10, wherein the friction ring (1) consists of gray cast iron, in particular of a lamellar gray cast iron or nodular cast iron.

12. friction ring (1) according to any one of the preceding claims 1-11,

- wherein the first ring section (10) and/or the second ring section (11) extends between an inner circumferential surface of the annular disk lying on the inside in the radial direction and an outer circumferential surface of the annular disk lying on the outside in the radial direction with an annular disk height, wherein the annular disk height is preferably at least 10 mm and at most 300 mm, and /or

- The ring connecting portion (12) between the connecting ring inner peripheral surface (13) and the Connecting ring outer peripheral surface (14) extends in the radial direction (R) with a connecting ring height, the connecting ring height preferably being at least 5 mm and a maximum of 300 mm, the connecting ring height preferably being smaller than the annular disc height. Friction ring (1) according to one of the preceding claims 1 to 12, wherein a degree of hardness decreases in the radial direction (R) or is constant, starting from an outer ring peripheral surface lying on the outside in the radial direction to an inner ring peripheral surface lying on the inside in relation to the ring outer peripheral surface in the radial direction. Friction ring (1) according to any one of the preceding claims 1 to 13, wherein the friction ring has an annular inner peripheral area, which extends from the ring inner peripheral surface in the direction of the ring outer peripheral surface, and has an annular outer peripheral area which, starting from the ring outer peripheral surface, extends in the direction of the ring inner peripheral surface , and an annular central peripheral portion extending between the annular inner peripheral portion and the annular outer peripheral portion, wherein the degree of hardness in the annular central peripheral portion is lower than in the annular inner peripheral portion and/or the annular outer peripheral portion. Friction ring (1) according to one of the preceding claims 1 to 14, wherein the degree of hardness is between 100 hardness Brinell tungsten carbide and 250 hardness Brinell tungsten carbide, in particular between 150 hardness Brinell tungsten carbide and 225 hardness Brinell tungsten carbide. Friction ring (1) according to one of the preceding claims 1 to 15, having a structure comprising pearlite, in particular lamellar pearlite, steadite and ferrite as structural components. Friction ring (1) according to one of the preceding claims 1 to 16, wherein the structural component perlite is between 70% and 100%, in particular between 80% and 95%, particularly preferably between 90% and 95%, and/or the structural component steadite is between 0% and 20%, in particular between 5% and 15%, particularly preferably between 5% and 10%, and/or

- The ferrite component of the structure is between 0% and 30%, in particular between 0% and 5%, particularly preferably between 0% and 1%. Friction ring (1) according to one of the preceding claims 1 to 17, wherein the structural component ferrite decreases in the radial direction (R) starting from an outer ring peripheral surface lying on the outside in the radial direction to an inner ring peripheral surface lying in the radial direction in relation to the ring outer peripheral surface and/or the structural component ferrite is predominantly adjacent is provided to the ring outer peripheral surface. Brake disc for a disc brake (2) of a vehicle (3), having a flange unit which is designed for attachment to a hub, in particular a wheel hub, and a friction ring (1) according to one of the preceding claims, which is connected torque-proof to the flange unit , wherein preferably the flange unit consists of a light metal, in particular aluminum, or essentially comprises this. Disc brake (2) for a vehicle (3), having a friction ring (1) according to any one of the preceding claims 1-18 and/or a brake disc according to the preceding claim 19 and a brake caliper arranged on the friction ring (1) and/or the brake disc with brake pads which are designed to delay a rotary movement of the friction ring (1) and/or the brake disc relative to a chassis. Vehicle (3) having a friction ring (1) according to any one of the preceding claims 1-18 and/or a brake disc according to the preceding claim 19 and/or a disc brake (2) according to the preceding claim 20. Use of a friction ring (1) according to a of the preceding claims 1-18 for a brake disk of a disk brake (2) of a vehicle (3), the vehicle (3) being in particular a passenger vehicle and/or a commercial vehicle and/or a two-wheeler. Method (1000) for producing a friction ring (1), in particular a friction ring (1) according to one of the preceding claims 1-18, for a brake disc of a disc brake (2) of a vehicle (3), the friction ring (1) having:

- a first ring section (10) with a first braking surface (10a) formed on the front side and a second ring section (11) arranged at a distance from the first ring section (10) in an axial direction (A) with a second braking surface (11a) formed on the front side, and

- a ring connecting section (12) connecting the first ring section (10) to the second ring section (11), and the method characterized by the steps:

- providing a centrifugal casting machine with a chill mold for centrifugal casting, the chill mold being in particular cylindrical, preferably tubular,

- Applying a sizing to an inside of the permanent mold,

- Feeding a molten centrifugal casting mass, in particular as molten gray cast iron, particularly preferably as molten lamellar gray cast iron, into the chill mold coated with the sizing,

- centrifugal casting of the supplied centrifugal mass,

- Cooling of the centrifugally cast centrifugal mass so that it solidifies into a tubular cast blank,

shot blasting the cooled tubular casting blank, and

Production of the brake disk with the first ring section (10) with the first braking surface (10a) arranged on the front side and the second ring section (11) with the second braking surface arranged on the front side (1 1 a) by mechanical processing, in particular by turning or milling.

24. Method (1000) according to the preceding claim 23,

- wherein the step of producing the brake disc comprises sawing off a brake disc blank from the cooled cast blank, and/or the method further comprises the steps:

- Introducing through-holes (15), in particular in a radial direction (R), preferably in the ring connecting section (12), and/or

- Introducing a plurality of perforation bores (17) which extend between the first and second braking surface (11a), in particular through connecting webs (16) of the ring connecting section (12), and/or

25. The method according to any one of the preceding claims 23 or 24, wherein the step of centrifugal casting occurs at a speed in a range between 400 rpm and 1500 rpm for a spin time in a range between 1000 seconds and 3000 seconds.

26. The method according to any one of the preceding claims 23 to 25, wherein the step of cooling takes place over a cooling time in a range between 10 seconds and 180 seconds.

27. The method according to any one of the preceding claims 23 to 26, wherein the step of applying the size layer on the inside of the chill mold comprises: - Application of the size layer at a speed in a range between 400 revolutions per minute and 1,800 revolutions per minute over a first application time in a range between 10 seconds and 50 seconds. 28. The method according to any one of the preceding claims 23 to 27, wherein the centrifugal casting mass to be supplied is heated in a furnace to a temperature in a range between 1350 °C and 1490 °C and/or in a pan to a temperature in a range between 1350 °C and 1490 °C was heated.