Friction ring for a brake drum of a drum brake of a vehicle, brake drum of a drum brake of a vehicle, vehicle, use of a friction ring for a brake drum of a drum brake of a vehicle, and method for producing a friction ring

Abstract

The invention relates to a friction ring (1) for a brake drum of a drum brake (2) of a vehicle (3), said friction ring (1) comprising: a ring outer circumferential surface (10) and a ring inner circumferential surface (11), between which the friction ring (1) extends in a radial direction (R) with a friction ring height (12), and a first and second end surface (13, 14), between which the friction ring (1) extends in an axial direction (A), orthogonal to the radial direction (R), with a friction ring width (15), wherein the ring outer circumferential surface (10) has a profiled surface with multiple elevations (20), wherein, starting from the ring outer circumferential surface (10), the elevations (20) extend along an elevation axis (E) from an elevation base (23) to an elevation head (24), characterised in that, neighbouring elevations (20) on the ring outer circumferential surface (10) are spaced apart from one another with a distance (22) of at least 0.1 mm and max. 1.5 mm in relation to the elevation heads (24) of the neighbouring elevations (20).

Description

[0001] Friction ring for a brake drum of a drum brake of a vehicle, brake drum of a drum brake of a vehicle, vehicle, use of a friction ring for a brake drum of a drum brake of a vehicle and method for producing a friction ring

[0002] The invention relates to a friction ring for a brake drum of a drum brake of a vehicle and to a brake drum for a drum brake of a vehicle. Furthermore, the invention relates to the use of a friction ring and / or a brake drum for a drum brake of a vehicle. Furthermore, the invention relates to a vehicle. Furthermore, the invention relates to a method for producing a friction ring for a brake drum of a drum brake of a vehicle.

[0003] A vehicle is, for example, a motorcycle, a passenger car, a truck, or even a trailer. A vehicle is also, in particular, a bicycle. Furthermore, a vehicle can also be, for example, a rail-bound vehicle, an aircraft, or the like. Drum brakes can also be used, for example, on cranes or the like.

[0004] Drum brakes belong to the class of friction brakes. The drum brake has a brake drum that is rotatably mounted relative to the chassis of a vehicle. A wheel, in particular the wheel rim, is usually attached to the brake drum. The drum brake also typically comprises a wheel brake cylinder, brake shoes, an adjusting device, and a return device, for example tension springs, which are connected to the chassis of the vehicle via a brake carrier plate. In particular, the brake shoes are generally arranged within the brake drum so that they engage with a braking surface of the brake drum during braking. It is known to construct brake drums in multiple pieces. In particular, it is known for brake drums to have a drum housing that is attached to the wheel or rim, which is connected to a friction ring that engages (frictionally contacts) with the brake shoes during braking.

[0005] Thus, a drum brake for a vehicle can be used to decelerate or completely stop the rotational movement of the vehicle's wheel relative to the vehicle's chassis ("full braking"). A drum brake serves to decelerate the vehicle. During braking, the vehicle's kinetic energy is converted into thermal energy, which must be dissipated to the environment for the drum brake to provide efficient braking. The ability of the brake drum to dissipate thermal energy to the environment via convection elements via thermal radiation depends primarily on the mass of the brake drum, the material properties, and the component geometry.

[0006] It is known to manufacture brake drums using casting processes such as sand casting, using individual castings in vertical or horizontal processes. These manufacturing processes are labor-intensive and time-consuming; for example, cores must be produced using the core shooting process to achieve the desired brake drum geometry. However, the core shooting process requires the use of substances that are harmful to health and the environment. Brake drums manufactured using the sand casting process, in particular, must subsequently undergo complex cleaning and blasting processes before they can be machined. Furthermore, brake drums manufactured in this way generally exhibit uneven mechanical and material properties in the radial direction.For example, the hardness and microstructure gradients of friction rings produced using sand casting are uneven in the radial direction and cannot be specifically adjusted to ensure even wear over the service life of a drum brake, for example. 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, microstructural deformities, and whitening due to insufficient casting allowances and excessively rapid cooling. Finally, normalization annealing is sometimes necessary to relieve process-related stresses. This is not only time-consuming, but also requires energy resources and pollutes the environment.

[0007] It is therefore an object of the present invention to provide a friction ring for a brake drum of a drum brake of a vehicle, a brake drum of a drum brake of a vehicle, a vehicle, a use of a friction ring and / or a brake drum for a drum brake of a vehicle, a method for producing a friction ring for a brake drum of a drum brake of a vehicle, which eliminate or reduce one or more of the aforementioned disadvantages.

[0008] According to one aspect, the object is achieved by a friction ring for a brake drum of a drum brake of a vehicle according to claim 1.

[0009] In the operating state of the drum brake, the friction ring according to the invention forms a unit with a drum housing as the brake drum. In this operating state, the friction ring is connected to the drum housing in such a way that an axial force and / or a braking torque can be transmitted between the friction ring and the drum housing. A friction ring is therefore preferably designed for a torque-resistant connection to the drum housing. Additionally or alternatively, the friction ring is further designed for a connection to the drum housing in order to transmit axial forces. In particular, the friction ring is designed to engage with brake shoes for braking a vehicle. During braking, a frictional connection is created between the brake shoes and the friction ring.In this respect, the friction ring must be designed to be particularly low-wear with regard to braking and to such an extent that it efficiently dissipates the thermal energy induced during braking in a particularly advantageous manner for effective braking.

[0010] The friction ring according to the invention for a brake drum of a vehicle's drum brake has an outer peripheral surface and an inner peripheral surface. The friction ring extends radially between the outer peripheral surface and the inner peripheral surface with a friction ring height. The friction ring height allows the stability of the brake drum and the thermal conductivity of the drum brake to be specifically adjusted.

[0011] The mounted friction ring is in operating condition via the outer peripheral surface of the ring in

[0012] Contact with the drum housing. It is therefore provided that the outer peripheral surface of the friction ring is designed for a connection to the drum housing. In particular, the outer peripheral surface of the ring is designed for a materially bonded and / or positively bonded and / or non-positively bonded connection to the drum housing. During braking, a braking torque is transmitted from the friction ring to the drum housing and thus to the wheel or rim attached to the drum housing via the outer peripheral surface of the ring. In this respect, the outer peripheral surface of the friction ring is to be designed for a torque-resistant connection to the drum housing. Furthermore, the outer peripheral surface of the friction ring is preferably designed for a transmission of an axial force from the friction ring to the drum housing.

[0013] Furthermore, it is provided that the ring's inner peripheral surface is designed as a braking surface which, in the operating state during vehicle braking, engages the brake shoes of the drum brake. In this respect, the ring's inner peripheral surface is designed to achieve a braking effect on the vehicle in interaction with the brake shoes of the drum brake. By appropriately machining the ring's inner peripheral surface, a particularly preferred coefficient of friction can be set which enables a braking effect without the time-consuming and complex "running-in" of the drum brake, so that the braking performance required for vehicle operation is available right from the start. In particular, the ring's inner peripheral surface is designed in such a way that it exhibits uniform wear behavior and dissipates the thermal energy induced by friction between the ring's inner peripheral surface and the brake shoes outwards towards the ring's outer peripheral surface.

[0014] The friction ring further has a first and a second end face. Between the first and second end faces, the friction ring extends in an axial direction, orthogonal to the radial direction, with a friction ring width. The ring width is designed depending on the required braking performance. If higher braking performance is desired, a larger ring width should be selected than for lower braking performance requirements.

[0015] It is provided that the ring outer peripheral surface has a profiled surface with a plurality of elevations. A plurality of elevations is in particular a large number of elevations. A plurality of elevations preferably comprises several thousand elevations. The elevations extend from the ring outer peripheral surface along an elevation axis from an elevation foot to a elevation head with an elevation height. Preferably, the elevation foot is that section of an elevation that is provided for the transmission of force and / or torque between the ring outer peripheral surface and the elevation. The elevation head forms in particular that section of an elevation that is provided for the transmission of force and / or torque between the drum housing of the friction ring and the elevation of the friction ring. It can be preferred for an intermediate section to extend between the elevation foot and the elevation head.Preferably, the raised foot extends over more than 0%, 5%, 10%, 20%, 30%, 40%, 50%, 60%, or 70% of the raised height and / or a maximum of 5%, 10%, 20%, 30%, 40%, 50%, 60%, or 70% of the raised height. Furthermore, it is preferred that the raised head extends over more than 0%, 5%, 10%, 20%, 30%, 40%, 50%, 60%, or 70% of the raised height and / or a maximum of 5%, 10%, 20%, 30%, 40%, 50%, 60%, or 70% of the raised height.

[0016] Preferably, the extension of a raised base and the extension of a raised head of a raised portion are configured such that they are designed for force and / or torque transmission and / or heat transfer of a similar magnitude. This ensures the most uniform possible force and / or torque transmission and / or heat transfer between the friction ring and the drum housing during operation.

[0017] It is preferred that the elevations have a random shape. In particular, it is provided that at least two, preferably several, and especially all, elevations have different shapes.

[0018] It is provided that the elevations of the outer peripheral surface of the ring engage with the drum housing in the operating state to connect the friction ring to the drum housing. It is preferred that the outer peripheral surface of the ring, in particular the elevations, of the friction ring be designed for a positive and / or material-locking and / or non-positive connection with the drum housing.

[0019] Furthermore, it is provided that elevations are arranged adjacently on the ring's outer circumferential surface. The elevations are arranged in relation to one another such that the elevation heads of the adjacent elevations are spaced apart from one another by a distance of at least 0.1 mm and a maximum of 1.5 mm. The arrangement of the elevations with this distance between the adjacent elevations enables the heat generated during braking to be efficiently dissipated from the friction ring to the drum housing in order to ensure constant braking performance during braking, and a torque-resistant connection can be established between the friction ring and the drum housing.

[0020] The minimum distance ensures in particular that material of the drum housing can penetrate between elevations for force and / or torque transmission and / or heat transfer. The maximum distance preferably ensures a sufficient number of connection points between the friction ring and the drum housing that are required for force and / or torque transmission and / or heat transfer. In a preferred embodiment, it can be provided that the elevation heads of the adjacent elevations are spaced from one another by a distance of at least 0.1 mm, in particular at least 0.5 mm, and a maximum of 1 mm, in particular a maximum of 0.7 mm. This embodiment enables particularly suitable force and / or torque transmission and / or heat transfer between the friction ring and the drum housing in the operating state.

[0021] The minimum and maximum distance between the protrusion heads of adjacently arranged protrusions preferably refers to the distance between the highest points of the protrusion heads of the adjacently arranged protrusions. Furthermore, it may be preferred that the minimum and maximum distance between the protrusion heads of adjacently arranged protrusions be the smallest distance between the outer surfaces of the protrusion heads of the adjacently arranged protrusions.

[0022] It should be understood that the spacing between one pair of adjacent protrusions may be different from that of a different pair of adjacent protrusions. For example, the spacing between one pair of adjacent protrusions may be 0.1 mm, while the spacing between the other pair may be 1.5 mm.

[0023] For further advantages, design variants, and design details of the friction ring according to the invention and its further developments, reference is also made to the following description of the corresponding features and developments of the brake drum, the vehicle, and the methods for producing a friction ring and for producing a brake drum. According to a preferred development, the friction ring is designed as a one-piece centrifugally cast part. In particular, a centrifugally cast part is produced using a permanent mold casting process.

[0024] This has the effect that, depending on the temperature control of the mold and the rotational speed in the radial direction of the friction ring, a desired microstructure and hardness profile can be precisely adjusted. In particular, this has the advantage that the friction ring has a uniform material density in the radial and circumferential directions and is therefore free of imbalances. Therefore, when using friction rings manufactured in this way, imbalances do not have to be eliminated before installation on the vehicle, which is a time-consuming process. In particular, the molds used to produce the friction ring can be precisely tempered, eliminating the need for normalization annealing. Furthermore, the complex post-processing steps of cleaning and blasting are eliminated with friction rings manufactured in this way.

[0025] Furthermore, a friction ring manufactured as a centrifugally cast part has the advantage that comparatively light slag, pores, inclusions, etc. are transported radially inwards during the liquid phase by the centrifugal forces that push the heavier cast iron towards the outer diameter and are deposited on the inner diameter or in the inner machining allowance of a cast blank of the friction ring.

[0026] A friction ring produced by 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. Furthermore, the cooling process after centrifugal casting can be precisely controlled, so that a friction ring produced in this way is free of cooling stresses. In particular, the cooling process is controlled during centrifuging. Preferably, the cast friction ring blank is not cooled in a controlled manner after removal from the mold. In particular, the cooling process after removal depends on the ambient temperature of the friction ring blank. Furthermore, a controlled cooling process allows hardness and microstructure to be adjusted depending on customer requirements. Furthermore, a centrifugally cast friction ring already has a high balance quality, which is further enhanced by the subsequent mechanical processing.By specifically adjusting the hardness and microstructure, the best possible wear parallelism can be ensured over the entire service life of the drum brake. In particular, the desired elevations on the outer peripheral surface of the friction ring can be created by using appropriate coatings. The coating is, in particular, a mixture of water and sand and / or silicate. The silicate is preferably an aluminum silicate. In particular, a coating comprising water and sand is particularly suitable for producing the desired elevations on the outer peripheral surface of the friction ring.

[0027] Furthermore, according to a preferred embodiment of the friction ring, it is provided that the elevations have a height of at least 0 mm and / or a maximum of 2 mm. It is preferred that the elevation height of the elevations is more than 0 mm and / or a maximum of 2 mm. With elevations with heights of more than 2 mm, the transfer of heat for heat dissipation may be improved, but the transfer of the braking torque may be only possible to a limited extent. In this respect, embodiments with heights of more than 2 mm are conceivable and also common, but less preferred. In particular, it is provided that the elevations have a height of more than 0 mm; preferably, the elevations have a height of at least 0.1 mm and in particular of at least 0.25 mm. It can also be preferred that the elevations have heights of at least 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm or 1 mm.The elevation height extends between the elevation base of an elevation and the elevation head of the elevation. The elevation head of an elevation is preferably a peak of an elevation with the maximum height, in particular starting from the elevation base. The elevation base of an elevation begins in particular at a local minimum of the ring outer peripheral surface between the adjacent elevations. The local minimum of the ring outer peripheral surface is defined in particular by the minimum distance between the ring outer peripheral surface and the ring inner peripheral surface between the adjacent elevations.

[0028] Elevations extending in the radial direction in this area can, on the one hand, be produced simply and cost-effectively by using appropriate coatings and, on the other hand, enable a particularly advantageous transmission of the braking torque from the friction ring to a drum housing of the brake drum. Furthermore, this preferred embodiment transfers the heat from the ring's outer peripheral surface to the drum housing arranged on the ring's outer peripheral surface in the operating state in a particularly advantageous manner. Furthermore, according to a preferred embodiment of the friction ring, the ring's outer peripheral surface has at least 10 elevations each 1 cm 2 and / or a maximum of 70 elevations per 1 cm 2 has.

[0029] Such a number of elevations in this area per 1 cm 2On the one hand, it can be manufactured easily and cost-effectively through the use of appropriate coatings, and on the other hand, it enables a particularly advantageous transmission of the braking torque from the friction ring to a drum housing of the brake drum. Furthermore, this preferred embodiment particularly advantageously transfers heat from the outer peripheral surface of the ring to the drum housing arranged on the outer peripheral surface of the ring during operation.

[0030] According to a further preferred development of the friction ring, the elevations on the outer circumferential surface of the ring are homogeneous.

[0031] According to a further preferred development of the friction ring, the elevations have a cross-sectional area. The cross-sectional area extends, in particular, orthogonally to the elevation axis.

[0032] It is preferably provided that the cross-sectional area varies along the elevation axis, starting from the elevation base in the direction of the elevation head, in particular decreases and / or increases. Additionally or alternatively, it is preferably provided that the elevations have a first section or a plurality of first sections in which the cross-sectional area decreases along the elevation axis in the direction of the elevation head. Furthermore, it is preferably provided additionally or alternatively that the elevations have a second section or a plurality of second sections in which the cross-sectional area increases along the elevation axis in the direction of the elevation head. Furthermore, it is particularly provided additionally or alternatively that the cross-sectional area is designed as a free-form surface.

[0033] Additionally or alternatively, the elevation has a foot width of at least 0.1 mm and / or a maximum of 3 mm at the base of the elevation. Furthermore, the elevations additionally or alternatively have a head width of at least 0 mm and / or a maximum of 3 mm at the head of the elevation. Furthermore, it is preferably provided that the foot width of an elevation is greater than the head width of the elevation or that the foot width of an elevation corresponds to the head width of the elevation. Elevations with such foot widths and / or head widths enable a particularly advantageous transmission of the braking torque from the friction ring to a drum housing of the brake drum. Furthermore, this preferred embodiment transfers the heat from the ring's outer peripheral surface to the drum housing arranged on the ring's outer peripheral surface in the operating state in a particularly advantageous manner.

[0034] Furthermore, according to a preferred development of the friction ring, it is provided that the elevations have a cross-sectional shape. In particular, it is provided that the cross-sectional shape varies along the elevation axis, starting from the elevation base in the direction of the elevation head, in particular decreases and / or increases. Additionally or alternatively, it is preferred that the cross-sectional shape is round, in particular concave and / or convex, and / or polygonal, in particular polygonal. Furthermore, it is additionally or alternatively preferably provided that the cross-sectional shape is irregular, in particular free-form. Furthermore, additionally or alternatively, one of the elevations or several of the elevations have one or more undercuts. These have the advantage that they can produce a positive connection in the radial direction.In particular, this allows for further improved connection to elements surrounding the friction ring, such as a drum housing, for transmitting torque. In particular, it is additionally or alternatively provided that one or more of the elevations do not have an undercut.

[0035] A free-form cross-sectional shape has, in particular, polygonal and / or convex and / or concave shape sections.

[0036] Furthermore, according to a preferred development of the friction ring, at least two elevations, preferably all elevations, are different from one another. In particular, at least two elevations are different from one another with respect to their shape and / or extent in the circumferential direction and / or extent in the axial direction and / or extent in the radial direction.

[0037] It should be understood that the elevations meet the requirements of at least one of the above-mentioned areas. In particular, it is preferred that on the ring's outer peripheral surface, the adjacent elevations are spaced from one another by a distance of at least 0.1 mm and a maximum of 1.5 mm with respect to the elevation heads of the adjacent elevations, with at least two of the elevations being designed differently from one another. This preferred embodiment thus enables the heat generated during braking to be efficiently dissipated from the friction ring to the drum housing in order to ensure constant braking performance during braking, and a torque-resistant connection between the friction ring and the drum housing can be produced cost-effectively.

[0038] Furthermore, in a preferred embodiment of the friction ring, it is provided that the elevations are distributed in a circumferential direction, in particular unevenly distributed.

[0039] In a further preferred development of the friction ring, the first and / or second end face and / or the ring inner circumferential surface have a flat surface, wherein a flat surface is in particular a mechanically machined surface, for example a surface machined by turning and / or milling.

[0040] According to a further preferred development, the friction ring consists of grey cast iron, in particular of a lamellar grey cast iron or spheroidal cast iron.

[0041] According to a further preferred development of the friction ring, it is provided that the ring inner circumferential surface has an inner ring diameter of at least 50 mm, preferably at least 150 mm, particularly preferably 180 mm, and / or a maximum of 1000 mm, preferably a maximum of 300 mm, particularly preferably a maximum of 240 mm. Additionally or alternatively, it is provided that the ring outer circumferential surface has an outer ring diameter of at least 55 mm, preferably of at least 160 mm, particularly preferably of at least 200 mm, and / or a maximum of 1200 mm, preferably a maximum of 400 mm, particularly preferably a maximum of 300 mm.

[0042] Furthermore, according to a further preferred embodiment of the friction ring, the friction ring width is at least 10 mm, preferably at least 30 mm, particularly preferably at least 50 mm, and / or a maximum of 200 mm, preferably a maximum of 100 mm, particularly preferably a maximum of 80 mm.

[0043] Furthermore, according to a preferred development of the friction ring, the friction ring height is at least 5 mm, preferably at least 10 mm, particularly preferably at least 15 mm, and / or a maximum of 100 mm, preferably a maximum of 50 mm, particularly preferably a maximum of 45 mm.

[0044] Friction rings with such a friction ring width and / or such a friction ring height enable a particularly advantageous transmission of the braking torque from the friction ring to a drum housing of the brake drum. Furthermore, this preferred embodiment particularly advantageously transfers heat from the ring's outer peripheral surface to the drum housing, which is arranged on the ring's outer peripheral surface in the operating state. This effect is achieved in particular by a positive-locking arrangement of the ring's outer peripheral surface on the drum housing.

[0045] Furthermore, according to a preferred embodiment of the friction ring, the degree of hardness decreases in the radial direction from the outer peripheral surface of the ring to the inner peripheral surface. The degree of hardness is specified, for example, in Brinell tungsten carbide hardness. This specification is also known as Brinell hardness. For example, the test method can be carried out using 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, particularly in external areas where comparatively high braking torques can occur during operation. In particular, this makes it possible to use the friction ring over a comparatively long service life. In addition to comparatively above-average friction performance and heat transfer, the development of fine dust is minimized.

[0046] Furthermore, according to a preferred development of the friction ring, the friction ring has an annular inner circumferential region which extends from the ring inner circumferential surface in the direction of the ring outer circumferential surface, and an annular outer circumferential region which extends from the ring outer circumferential surface in the direction of the ring inner circumferential surface, and an annular central circumferential region which extends between the annular inner circumferential region and the annular outer circumferential region, wherein the degree of hardness in the annular central circumferential region is lower than in the annular inner circumferential region and / or the annular outer circumferential region. 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, the hardness is between 100 Brinell hardness of tungsten carbide and 250 Brinell hardness of tungsten carbide, in particular between 150 Brinell hardness of tungsten carbide and 225 Brinell hardness of tungsten carbide. Preferably, the hardness is in the range of.

[0047] Ring inner peripheral surface in a range of 170 Brinell hardness tungsten carbide. Alternatively or additionally, it is preferred that the hardness level is in the range of

[0048] The outer peripheral surface of the ring is in the range of 200 Brinell hardness tungsten carbide. A particularly long-lasting and reliable braking effect of the friction rings has been observed in this specified range.

[0049] Furthermore, according to a preferred embodiment of the friction ring, the friction ring has a structure comprising pearlite, in particular lamellar pearlite, steadite, and ferrite as structural components. The structural components pearlite, in particular lamellar pearlite, and / or steadite are preferably distributed substantially evenly or homogeneously between the inner circumferential surface of the ring and the outer circumferential surface of the ring. A friction ring having a structure with these said components can achieve a particularly advantageous and long-lasting braking effect. In particular, it has been 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%, sometimes even 70% higher than that of previously known friction rings. In addition to comparatively above-average friction performance and heat transfer, the development of fine dust is minimized.

[0050] In particular, according to one embodiment of the friction ring, it is provided that the structural component pearlite lies between 70% and 100%, in particular between 80% and 95%, particularly preferably between 90% and 95%, and / or the structural component steadite lies between 0% and 20%, in particular between 5% and 15%, particularly preferably between 5% and 10%, and / or the structural component ferrite lies between 0% and 30%, in particular between 0% and 5%, particularly preferably between 0% and 1%. A friction ring which has a structure with structural components in the stated range enables high, reliable and long-lasting braking performance.

[0051] Furthermore, according to another preferred embodiment of the friction ring, the ferrite structural component decreases in the radial direction from the ring's outer peripheral surface to the ring's inner peripheral surface and / or the ferrite structural component is provided predominantly adjacent to the ring's outer peripheral surface. This is based on the inventors' finding that friction rings with a comparatively high, long-lasting friction effect can be achieved in this way.

[0052] In particular, a further preferred development of the friction ring provides that the edge formed by the ring's outer peripheral surface and the first end face is designed as a chamfer or rounded portion, and / or the edge formed by the ring's outer peripheral surface and the second end face is designed as a chamfer or rounded portion. This has the particular advantage that the notch effect of the friction ring, particularly in the assembled state as part of a brake drum for a drum brake, is minimized, and thus the service life of the brake drum or drum brake can be extended by this preferred design of the friction ring.

[0053] Finally, according to a preferred embodiment of the friction ring, the chamfer has an angle in a range between 0° and 45° and / or a width between 0.1 mm and 5 mm. Additionally or alternatively, the rounding can preferably have a radius between 0.5 mm and 5 mm.

[0054] According to a further aspect, the invention is achieved by a brake drum for a vehicle, which has a friction ring according to the aspect described above or according to the preferred embodiments thereof.

[0055] In particular, it is provided that the drum housing extends in a radial direction between an inner housing circumferential surface and an outer housing circumferential surface which, in the radial direction, lies outer compared to the housing inner circumferential surface. It is to be understood that the drum housing, as previously explained in relation to the friction ring, is connected to the friction ring, in particular for transmitting a braking torque and / or for transmitting axial forces. Preferably, the drum housing and the friction ring are connected to one another in a materially bonded and / or positively locking and / or non-positively locking manner. In particular, it is provided that the drum housing is cast around the friction ring. As a result, the friction ring is cast around the drum housing in such a way that the drum housing is connected to the outer circumferential surface of the friction ring at the housing inner circumferential surface. In particular, the drum housing encloses the elevations of the friction ring.In particular, the drum housing and the friction ring are irreversibly connected to one another. The drum housing preferably extends axially between a first and second housing end face. Furthermore, the drum housing has a flange portion which, on the side of the first housing end face, extends inward in a plate-like manner from the outer peripheral surface of the housing in the radial direction. The flange portion, in particular, has a connection for attaching a wheel or a rim. For example, the flange portion for attaching the wheel or the rim can have five through-holes with internal threads to which a wheel or a rim can be screwed in a torque-resistant manner.

[0056] Preferably, the connection between the drum housing and the friction ring is established by casting the drum housing around the friction ring. Furthermore, the drum housing is preferably made of a material with a melting temperature lower than the melting temperature of the material from which the friction ring is made.

[0057] For further advantages, design variants and design details of the brake drum according to the invention and their developments, reference is also made to the preceding description of the corresponding features and developments of the friction ring as well as to the following description of the corresponding features and developments of the vehicle and the methods.

[0058] According to a preferred development of the brake drum, the brake drum has a drum housing to which the friction ring is connected, in particular positively connected, wherein the connection between the friction ring and the drum housing is designed to be torque-resistant for transmitting torques and / or is designed to transmit axial forces.

[0059] Furthermore, according to a preferred development of the brake drum, the drum housing is made of a material that is different from the material of the friction ring, with the drum housing preferably being made of a light metal. This has particular advantages with regard to weight and, preferably, also with regard to thermal conductivity.

[0060] According to a further aspect, the invention is achieved by using a friction ring described above and / or a brake drum described above for a drum brake of a vehicle, wherein the vehicle is in particular a passenger car and / or a commercial vehicle and / or a two-wheeler.

[0061] For further advantages, design variants and design details of the use according to the invention of the friction ring and / or the brake drum for a drum brake of a vehicle, reference is also made to the preceding description of the corresponding features and developments of the friction ring, the brake drum and to the following description of the corresponding features and developments of the vehicle and the methods.

[0062] According to a further aspect, the invention is achieved by a vehicle having a friction ring and / or a brake drum as described above.

[0063] For further advantages, design variants and design details of the use of the vehicle according to the invention, reference is also made to the preceding description of the corresponding features and developments of the friction ring, the brake drum and to the following description of the corresponding features and developments of the methods.

[0064] According to a further aspect, the invention is achieved by a method for producing a friction ring, in particular a previously described friction ring, for a brake drum of a drum brake of a vehicle, wherein the friction ring has a ring outer peripheral surface and a ring inner peripheral surface, between which the friction ring extends in a radial direction with a friction ring height, and a first and second end face, between which the friction ring extends in an axial direction, orthogonal to the radial direction, with a friction ring width, wherein the ring outer peripheral surface has a profiled surface with a plurality of elevations, wherein the elevations extend from the ring outer peripheral surface along an elevation axis from an elevation base to an elevation head, and the method comprises the following steps:

[0065] Providing a centrifugal casting machine with a mold for centrifugal casting,

[0066] Applying at least one coating layer to an inner side of the mold, feeding a centrifugal casting mass, in particular as molten grey cast iron, particularly preferably as molten lamellar grey cast iron or spheroidal cast iron, into the mold coated with at least one coating layer,

[0067] Centrifugal casting of the supplied centrifugal mass, and

[0068] Cooling of the centrifugally cast mass to form a tubular casting blank.

[0069] It may be preferable to design the mold such that the friction rings can be individually produced in the mold using the centrifugal casting process. In particular, it may be preferable for the mold to be designed to individually produce a single friction ring or multiple friction rings using the centrifugal casting process. When producing a friction ring individually, it is particularly important to understand 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 individual production of a friction ring, cutting individual friction ring blanks from the cast blank is not necessary.

[0070] For further advantages, embodiment variants and embodiment details of the method according to the invention for producing a friction ring, in particular a previously described friction ring, for a brake drum of a drum brake of a vehicle, reference is also made to the preceding description of the corresponding features and developments of the friction ring, the brake drum and the vehicle.

[0071] According to a preferred development of the method, the method further comprises the following steps:

[0072] Blasting the cooled tubular casting blank, and / or

[0073] Mechanical machining, in particular turning, of a first and / or second end face and / or an inner circumferential surface of the cast blank and / or friction ring blank, wherein the mechanical machining comprises in particular sawing off a friction ring blank from the tubular cast blank.

[0074] The friction rings described above are particularly suitable for producing a brake drum, in particular a brake drum as described above, for a drum brake of a vehicle. A corresponding manufacturing method may, for example, comprise the following steps:

[0075] Providing a previously described friction ring and / or a previously described brake drum and / or a friction ring manufactured according to a previously described method,

[0076] Casting a drum housing around the friction ring, and / or

[0077] Remachining the inner peripheral surface of the cast friction ring.

[0078] According to a preferred development of the method, the centrifugal casting step is carried out at a speed in a range between 400 revolutions per minute and 1,500 revolutions per minute for a spinning time in a range between 80 seconds and 360 seconds. This enables the production of a friction ring with a comparatively high friction effect and a long service life.

[0079] Furthermore, according to a preferred development of the method, the cooling step is carried out over a cooling time in a range between 10 seconds and 180 seconds.

[0080] Furthermore, according to a preferred embodiment of the method, the step of applying at least one coating layer to an inner side of the mold comprises:

[0081] - applying a first coating 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, and / or

[0082] - Applying a second coating layer, different from the first coating layer, at a rotational speed in a range between 400 revolutions per minute and 1,800 revolutions per minute over a second application time in a range between 10 seconds and 50 seconds. According to a further preferred development of the method, 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 ladle to a temperature in a range between 1350°C and 1490°C.

[0083] For further advantages, embodiment variants and embodiment details of the method according to the invention for producing a friction ring, in particular a previously described friction ring, for a brake drum of a drum brake of a vehicle, reference is also made to the preceding description of the corresponding features and developments of the friction ring, the brake drum and the vehicle.

[0084] The method according to the invention for producing a friction ring and the possible further developments have features or method steps that make them particularly suitable for use with a friction ring according to the invention and / or a brake drum according to the invention and / or a vehicle according to the invention, as well as the respective further developments. For further advantages, embodiments, and design details of this further aspect and their possible further developments, reference is also made to the above description of the corresponding features and developments of the friction ring, the brake drum, and the vehicle.

[0085] Preferred embodiments of the invention are explained by way of example with reference to the accompanying figures. They show:

[0086] Fig. 1 : a schematic side view of an exemplary embodiment of a

[0087] Vehicle with a brake drum in a preferred embodiment;

[0088] Fig. 2: a schematic view of the preferred embodiment shown in Figure 1

[0089] Design of the brake drum;

[0090] Fig. 3a, b: a schematic side view and top view of the preferred embodiment of the friction ring provided in Figure 2;

[0091] Fig. 4a, b: a schematic detailed view in a side view and a top view of a preferred embodiment of an outer peripheral surface of the friction ring shown in Figure 2; Fig. 5a, b: a schematic detailed view in a side view and a top view of another preferred embodiment of an outer peripheral surface of the friction ring shown in Figure 2; and

[0092] Fig. 6: a schematic block diagram of a preferred embodiment of a

[0093] Method for producing a previously shown brake drum 2 with a previously shown friction ring 1.

[0094] Figure 1 shows a schematic side view of an exemplary embodiment of a truck 3 with a brake drum 2 of a drum brake in a preferred embodiment. The brake drum 2 is mounted for rotation relative to the chassis of the vehicle 3. The vehicle wheel is torque-fixed to the brake drum, so that during braking, the rotational movement of the wheel and the brake drum relative to the chassis of the vehicle 3 is decelerated.

[0095] Figure 2 shows a schematic, three-dimensional view of the brake drum 2 provided in Figure 1. The brake drum has a pot-shaped drum housing 4 within which a friction ring 1 is arranged.

[0096] The pot-shaped drum housing 4 is made of a light metal and has an annular section that extends in the radial direction R between an inner housing inner circumferential surface 41 and a comparatively outer housing outer circumferential surface 42. In the axial direction A, the drum housing 4 extends between a first and second housing end face 43, 44. Furthermore, the drum housing 4 has a flange section 45 that extends inward in the radial direction R on the side of the first housing end face 43 from the housing outer circumferential surface 42 in a plate-like manner. The flange section 45 has five through-holes with internal threads to which a wheel can be screwed in a torque-resistant manner. Of course, a flange section can also have, for example, four or ten through-holes.

[0097] The friction ring 1 is designed as a centrifugally cast part made of a lamellar grey cast iron or spheroidal cast iron and has a ring outer peripheral surface 10 and a ring inner peripheral surface

[0098] 11, between which the friction ring 1 is arranged in the radial direction R with a friction ring height

[0099] 12 extends. The friction ring height 12 is at least 5 mm and a maximum of 100 mm. The ring inner circumferential surface 11 preferably has an inner ring diameter 16 of at least 50 mm and a maximum of 1000 mm. The ring outer circumferential surface 10 preferably has an outer ring diameter 17 of at least 55 mm and a maximum of 1200 mm. Furthermore, the friction ring 1 has first and second end faces 13, 14, between which the friction ring 1 extends in the axial direction A, orthogonal to the radial direction R, with a friction ring width 15. The friction ring width 15 in the present case is at least 10 mm and a maximum of 200 mm. It should be understood that the geometric dimensions of the friction ring can vary depending on the area of ​​application, i.e. the required braking performance.

[0100] Figures 3a and 3b show a schematic side view and a schematic top view of the preferred embodiment of the friction ring provided in Figure 2.

[0101] The friction ring is arranged within the drum housing 4, so that the outer peripheral surface 10 of the friction ring 1 is connected in a torque-resistant manner to the inner peripheral surface 41 of the drum housing 4. For this purpose, the outer peripheral surface 10 of the ring has a profiled surface with a plurality of elevations 20, wherein the elevations 20 extend from the outer peripheral surface 10 of the ring along an elevation axis E from an elevation base 23 to an elevation head 24 with an elevation height 21. In the present case, the elevations 20 have an elevation height 21 of at least 0 mm and a maximum of 2 mm. Furthermore, it is provided that the elevations 20 arranged adjacently on the ring outer circumferential surface 10 are arranged at a distance 22 of at least 0.1 mm and a maximum of 1.5 mm from one another in relation to the elevation heads 24 of the adjacently arranged elevations 20.It is intended that the ring outer peripheral surface 10 has at least ten elevations of 1 cm each. 2 and a maximum of seventy elevations of 1 cm each 2 has.

[0102] This results, on the one hand, in a particularly torque-resistant connection of the friction ring 1 to the drum housing 4 and, on the other hand, in excellent heat conduction from the ring inner circumferential surface 11, against which the brake shoes of the drum brake bear for braking the vehicle 3, to the housing outer circumferential surface 42 of the drum housing 4.

[0103] Figures 4a and 4b as well as Figures 5a and 5b show a schematic detailed view in a side view and a top view of two preferred embodiments of the ring outer circumferential surface 10 of the friction ring 1 schematically illustrated in Figures 3a and 3b. In both preferred embodiments, it is provided that the elevations have a cross-sectional area that decreases along the elevation axis E, starting from the elevation base 23 in the direction of the elevation head 24. It is provided that the elevations on the elevation base 23 have a base width 25 of at least 0.1 mm and a maximum of 3 mm; on the elevation head 24, it is provided that the elevations have a head width 26 of at least 0 mm and a maximum of 3 mm, wherein in this case the base width 25 of an elevation is greater than its head width 26.

[0104] It should be understood that the cross-sectional shape of the elevations preferably varies along the elevation axis E, starting from the elevation base 23 in the direction of the elevation head. In particular, it may be preferred for the elevations to have concave and convex shapes, particularly preferably a round cross-sectional area, as is schematically shown in Figures 5a and 5b. Furthermore, it may be preferred for the cross-sectional area to be polygonal, as shown in Figures 4a and 4b. In particular, it is preferred for the elevations to have an undercut. Regardless of the embodiment, it can be seen that the elevations are distributed in the circumferential direction as well as in the axial direction, with an uneven distribution of the elevations being preferred. Preferably, all elevations are designed differently from one another.

[0105] In contrast to the ring's outer peripheral surface 10, the first and second end faces 13, 14, as well as the ring's inner peripheral surface 11, have a flat surface that has been machined by turning and / or milling. Therefore, the first and second end faces 13, 14, as well as the ring's inner peripheral surface 11, have an average roughness value typical for mechanical machining.

[0106] Figure 6 shows a schematic block diagram of a preferred embodiment of a method 1000 for producing a previously described brake drum 2 with a previously described friction ring 1. The method 1000 initially provides 1010 a centrifugal casting machine with a permanent mold for centrifugal casting. This is followed by the application 1020 of at least one coating layer to an inner side of the permanent mold. This is followed by the feeding 1030 of a centrifugal casting mass, particularly preferably as molten lamellar gray cast iron or spheroidal cast iron, into the permanent mold coated with at least one coating layer. Depending on the at least one coating layer, the elevations on the outer peripheral surface of the friction ring 1 are formed. This is followed by centrifugal casting 1040 of the supplied centrifugal mass. The centrifugally cast centrifugal mass is then cooled 1050 to form a tubular cast blank.After the cast blank has cooled, it is provided in this preferred embodiment that the cooled cast blank is blasted 1060 and then the first and second end faces 13, 14 as well as the ring inner peripheral surface 11 are machined by mechanical machining 1070, namely by sawing and turning.

[0107] To produce the brake drum, a friction ring 1 produced according to this method is then provided 1080 and a drum housing 4 is cast 1090 around the provided friction ring 1. This creates the connection between the housing inner circumferential surface and the elevations of the ring outer circumferential surface in order to, among other things, transmit the braking torque and to transfer the thermal energy to the outside to the

[0108] drum housing. Subsequently, the inner peripheral surface 11 of the cast-in friction ring 1 is remachined 1100 in order to achieve optimal braking effect with the friction ring.

[0109] List of reference symbols

[0110] 1 friction ring

[0111] 2 brake drums

[0112] 3 vehicles

[0113] 4 drum housings

[0114] 10 Ring outer peripheral surface

[0115] 11 Ring inner peripheral surface

[0116] 12 Friction ring height

[0117] 13 first frontal surface

[0118] 14 second front face

[0119] 15 friction ring width

[0120] 16 ring inner diameter

[0121] 17 ring outer diameter

[0122] 20 surveys

[0123] 21 elevation

[0124] 22 distance

[0125] 23 elevation foot

[0126] 24 Survey head

[0127] 25 feet wide

[0128] 26 head width

[0129] 41 Housing inner peripheral surface

[0130] 42 Housing outer peripheral surface

[0131] 43 first housing face

[0132] 44 second housing face

[0133] 45 flange section

[0134] A axial direction

[0135] E elevation axis

[0136] R Radial direction

[0137] U circumferential direction

Claims

Claims 1. Friction ring (1) for a brake drum (2) of a drum brake of a vehicle (3), the friction ring (1) comprising: - an outer circumferential surface (10) of the ring and an inner circumferential surface (11) between which the friction ring (1) extends in a radial direction (R) with a friction ring height (12), and - a first and second end face (13, 14) between which the friction ring (1) extends in an axial direction (A), orthogonal to the radial direction (R), with a friction ring width (15), wherein - the outer circumferential surface (10) has a profiled surface with several elevations (20), wherein the elevations (20) extend from the outer circumferential surface (10) along an elevation axis (E) from a elevation base (23) to a elevation head (24) with an elevation height (21), characterized in that - on the outer circumferential surface (10) adjacently arranged elevations (20) are arranged with a distance (22) of at least 0.1 mm and at most 1.5 mm between them in relation to the elevation heads (24) of the adjacently arranged elevations (20).

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

3. Friction ring (1) according to one of the preceding claims 1 or 2, wherein the protrusions (20) have a protrusion height (21) of at least 0 mm and / or a maximum of 2 mm.

4. Friction ring (1) according to one of the preceding claims 1 to 3, wherein the outer circumferential surface (10) of the ring has at least 10 protrusions per 1 cm² 2 and / or a maximum of 70 elevations per 1 cm 2 exhibits.

5. Friction ring (1) according to any one of the preceding claims 1 to 4, wherein the protrusions on the outer circumferential surface (10) of the ring are homogeneous.

6. Friction ring (1) according to any one of the preceding claims 1 to 5, wherein the projections (20) have a cross-sectional area, wherein - the cross-sectional area along the elevation axis (E) starting from the elevation base (23) towards the elevation head (24) varies, in particular decreases and / or increases, and / or - the elevations (20) have a first section or several first sections in which the cross-sectional area decreases along the elevation axis (E) in the direction of the elevation head (24) and / or have a second section or several second sections in which the cross-sectional area increases along the elevation axis (E) in the direction of the elevation head (24), and / or - the cross-sectional area is designed as a freeform surface, and / or - the elevation at the elevation base (23) has a base width (25) of at least 0.1 mm and / or a maximum of 3 mm, and / or - the elevation on the elevation head (24) has a head width (26) of at least 0 mm and / or a maximum of 3 mm, wherein - preferably the foot width (25) of a protrusion is greater than the head width (26) of the protrusion or the foot width (25) of a protrusion is equal to the head width (26) of the protrusion.

7. Friction ring (1) according to any one of the preceding claims 1 to 6, wherein the projections (20) have a cross-sectional shape, where - the cross-sectional shape varies along the elevation axis (E) starting from the elevation base (23) towards the elevation head (24), and / or - the cross-sectional shape is round, in particular concave and / or convex, and / or polygonal, in particular polygonal, and / or - the cross-sectional shape is irregular, especially freeform, and / or - one or more of the elevations (20) have an undercut or multiple undercuts, and / or - one or more of the surveys (20) do not show any undercut.

8. Friction ring (1) according to any one of the preceding claims 1 to 7, wherein at least two protrusions, preferably all protrusions, are different from each other.

9. Friction ring (1) according to one of the preceding claims 1 to 8, wherein the protrusions (20) are arranged in a circumferential direction (U) distributed, in particular unevenly distributed.

10. Friction ring (1) according to any one of the preceding claims 1 to 9, wherein the first and / or second end face (13, 14) and / or the inner circumferential surface (11) have a flat surface, wherein a flat surface is in particular a mechanically machined surface, for example a surface machined by turning and / or milling.

11. Friction ring (1) according to any one of the preceding claims 1 to 10, wherein the friction ring (1) is made of grey cast iron, in particular of lamellar grey cast iron or spheroidal graphite cast iron.

12. Friction ring (1) according to any one of the preceding claims 1 to 11 , wherein - the inner circumferential surface (11) of the ring has an inner diameter (16) of at least 50 mm, preferably at least 150 mm, particularly preferably 180 mm, and / or a maximum of 1000 mm, preferably a maximum of 300 mm, particularly preferably a maximum of 240 mm, and / or - the outer circumferential surface of the ring (10) has an outer ring diameter (17) of at least 55 mm, preferably at least 160 mm, particularly preferably at least 200 mm, and / or a maximum of 1200 mm, preferably a maximum of 400 mm, particularly preferably a maximum of 300 mm.

13. Friction ring (1) according to any one of the preceding claims 1 to 12, wherein the friction ring width (15) is at least 10 mm, preferably at least 30 mm, particularly preferably at least 50 mm, and / or a maximum of 200 mm, preferably a maximum of 100 mm, particularly preferably a maximum of 80 mm.

14. Friction ring (1) according to any one of the preceding claims 1 to 13, wherein the friction ring height (12) is at least 5 mm, preferably at least 10 mm, particularly preferably at least 15 mm, and / or at most 100 mm, preferably at most 50 mm, particularly preferably at most 45 mm.

15. Friction ring (1) according to any one of the preceding claims 1 to 14, wherein the degree of hardness decreases from the outer circumferential surface (10) of the ring to the inner circumferential surface (1 1) in the radial direction (R).

16. Friction ring (1) according to any one of the preceding claims 1 to 15, wherein the friction ring has an annular inner circumferential region extending from the inner circumferential surface (11) towards the outer circumferential surface (10), and an annular outer circumferential region extending from the outer circumferential surface (10) towards the inner circumferential surface (11), and an annular central circumferential region extending between the annular inner circumferential region and the annular outer circumferential region, wherein the degree of hardness in the annular central circumferential region is lower than in the annular inner circumference area and / or the annular Outer circumferential area. Friction ring (1) according to any one of the preceding claims 1 to 16, wherein the hardness is between 100 Brinell hardness of tungsten carbide and 250 Brinell hardness of tungsten carbide, in particular between 150 Brinell hardness of tungsten carbide and 225 Brinell hardness of tungsten carbide. Friction ring (1) according to any one of the preceding claims 1 to 17, comprising a microstructure comprising pearlite, in particular lamellar pearlite, steadite and ferrite as microstructural constituents. Friction ring (1) according to any one of the preceding claims 1 to 18, wherein - the microstructural constituent pearlite is between 70% and 100%, in particular between 80% and 95%, especially preferably between 90% and 95%, and / or - the structural constituent steadite is between 0% and 20%, in particular between 5% and 15%, most preferably between 5% and 10%, and / or - the ferrite content of the microstructure is between 0% and 30%, in particular between 0% and 5%, and most preferably between 0% and 1%. Friction ring (1) according to any one of the preceding claims 1 to 19, wherein the ferrite content decreases in the radial direction (R) from the outer circumferential surface (10) of the ring to the inner circumferential surface (11) of the ring and / or the ferrite content is predominantly adjacent to the outer circumferential surface (10) of the ring. Friction ring (1) according to any one of the preceding claims 1 to 20, wherein - the edge formed by the outer circumferential surface of the ring and the first end face is designed as a chamfer or rounding, and / or the edge formed by the outer circumferential surface of the ring and the second end face is designed as a chamfer or rounding.

22. Friction ring (1) according to the preceding claim 21, wherein - the chamfer has an angle in a range between 0° and 45° and / or a width between 0.1 mm and 5 mm; and / or - the rounding has a radius between 0.5 mm and 5 mm.

23. Brake drum (2) for a drum brake of a vehicle (3), the brake drum (2) comprising a friction ring (1) according to one of the preceding claims 1 to 22.

24. Brake drum (2) according to the preceding claim 23, the brake drum (2) comprising a drum housing (4) with which the friction ring (1) is connected, in particular positively connected, wherein the connection between the friction ring (1) and the drum housing (4) is designed to be torque-resistant for transmitting torques and / or axial forces.

25. Brake drum (2) according to one of the preceding claims 23 or 24, wherein the drum housing (4) is made of a material different from the material of which the friction ring (1) is made, wherein preferably the drum housing (4) is made of a light metal.

26. Use of a friction ring (1) according to any one of the preceding claims 1 to 22 and / or a brake drum (2) according to any one of the preceding claims 23 to 25 for a drum brake of a vehicle (3), wherein the vehicle (3) is in particular a passenger car and / or a commercial vehicle and / or a two-wheeler.

27. Vehicle (3) comprising a friction ring (1) according to any one of the preceding claims 1 to 22 and / or a brake drum (2) according to any one of the preceding claims 23 to 25. Method for manufacturing a friction ring (1), in particular a friction ring (1) according to one of the preceding claims 1 to 22, for a brake drum (2) of a drum brake of a vehicle (3), comprising a friction ring: - an outer circumferential surface (10) of the ring and an inner circumferential surface (11) between which the friction ring (1) extends in a radial direction (R) with a friction ring height (12), and - a first and second end face (13, 14) between which the friction ring (1) extends in an axial direction (A), orthogonal to the radial direction (R), with a friction ring width (15), wherein - the outer circumferential surface (10) has a profiled surface with several elevations (20), wherein the elevations (20) extend from the outer circumferential surface (10) along an elevation axis (E) from an elevation base (23) to an elevation head (24), and the method characterized by the steps: - Providing a centrifugal casting machine with a die for centrifugal casting, - Applying at least one coating layer to an inner side of the mold, - Feeding a centrifugal casting compound, in particular as molten grey cast iron, especially preferably as molten lamellar grey cast iron or ductile iron, into the die mold coated with at least one coating layer, - Centrifugal casting of the supplied centrifugal material, and - Cooling of the centrifugally cast material into a tubular casting blank.

29. Method according to the preceding claim 28, comprising the steps: - Blasting of the cooled tubular cast blank, and / or - Mechanical processing, in particular turning, of a first and / or second end face (13, 14) and / or of an inner circumferential surface (11) of the cast blank and / or friction ring blank, wherein the mechanical processing in particular includes sawing a friction ring blank from the tubular cast blank.

30. Method according to one of the preceding claims 28 or 29, wherein the centrifugal casting step is carried out at a rotational speed in a range between 400 revolutions per minute and 1,500 revolutions per minute for a centrifugal time in a range between 80 seconds and 360 seconds.

31. Method according to any one of the preceding claims 28 to 30, wherein the cooling step is carried out over a cooling time in a range between 10 seconds and 180 seconds.

32. Method according to any one of the preceding claims 28 to 31, wherein the step comprises applying the at least one coating layer to the inside of the mold: - Application of a first coating layer at a rotational speed in the range of 400 revolutions per minute and 1,800 revolutions per minute for a first application time in the range of 10 seconds and 50 seconds, and / or - Application of a second coating layer different from the first coating layer at a rotational speed in a range between 400 revolutions per minute and 1,800 revolutions per minute over a second application time in a range between 10 seconds and 50 seconds.

33. Method according to any one of the preceding claims 28 to 32, wherein the centrifugal casting compound to be supplied is heated in a furnace to a temperature in a range between 1350 °C and 1490 °C and / or heated in a pan to a temperature in a range between 1350 °C and 1490 °C.

Images