Disc brake with an internally ventilated, perforated brake disc

Abstract

In a disc brake (2) with a brake disc (1) having a virtual main disc plane (11), a disc hub (3), and two friction rings (5, 6) mounted on the disc hub (3) so as to be non-rotatable about an axis of rotation (4), arranged at an axial distance (8) from each other forming a cooling gap (7), and provided with holes (9, 10), the holes (9, 10) through the friction rings (5, 6) each extend at an angle (19) between 20° and 70° to the main disc plane (11). Viewed from the cooling gap (7), either all holes (9, 10) through both friction rings (5, 6) extend away from the axis of rotation (4) or all holes (9, 10) through both friction rings (5, 6) extend towards the axis of rotation (4).

Description

TECHNICAL FIELD OF THE INVENTION

[0001] The invention relates to a disc brake with a brake disc having the features of the preamble of independent patent claim 1. The brake disc of the disc brake is therefore a so-called internally ventilated or double brake disc with two friction rings arranged at an axial distance from one another, forming a cooling gap. STATE OF THE ART

[0002] Disc brakes with the features of the preamble of independent patent claim 1 are known in many embodiments. They are commercially available as internally ventilated or double-perforated brake discs. In the cooling gap between the two friction rings, webs extending radially to the axis of rotation or in a vane-like configuration are arranged. These webs connect the friction rings and, like a rotary or centrifugal pump, pump air away from the cooling axis through the cooling gap.

[0003] In various commercially available internally ventilated or double brake discs, the axial distance between the friction rings is not constant, but varies in the direction away from the axis of rotation.

[0004] A brake disc with cooling holes is known from DE 196 41 419 A1. The brake disc consists of a circular ring with a profiled inner edge and a number of through holes in the disc. The axes of the holes form an angle of between 25° and 65° with the plane of the disc. The axes of the holes are essentially aligned tangentially to a virtual circle around a rotational axis of the brake disc. To avoid the effect of significant transport of material from brake pads, the holes can be aligned essentially radially to the rotational axis instead of tangentially to the virtual circle. The advantage of the known brake disc is that, compared to a conventional brake disc, a larger cooling surface is achieved with the same number and dimensions of the holes.Another important advantage is said to arise from the airflow that forms through the holes, which has the dual effect of improving heat dissipation through convection and cleaning the holes. At the same time, noise from the disc is reduced by removing powder, whether from the brake pads or from the environment, which causes the typical squeaking and squeaking noises. Another advantage of the special design of the disc is said to be the acute entry angle at which the holes pass through the brake pads, which improves the removal of wear material from the brake pads. This should result in improved braking performance and a faster dissipation of the vehicle's kinetic energy, with the same pressure from the brake pads on the disc.The known brake disc is proposed as an alternative solution to a double disc in which radial cooling channels between two thin, parallel, connected discs, in which the air tends to flow outwards due to centrifugal force when the disc rotates, are connected to the side surfaces of the discs via axial holes that are perpendicular to the planes of the discs in order to enlarge the surface of the disc with the same diameter so that the heat can be better dissipated by radiation or convection.

[0005] US 2001 / 0032759 A1 discloses a brake disc with a disc chamber and a friction ring protruding therefrom, which is provided with holes whose axes are inclined relative to a main disc plane and whose cross-section, running transversely to the respective axis, decreases or increases from one side of the friction ring to the other. The holes can be aligned essentially tangentially to a virtual circle around a rotational axis or radially to the rotational axis of the brake disc. If the holes are aligned essentially radially, their free cross-section increases away from the rotational axis. The inclination of the holes relative to the main disc plane is intended to increase the flow through the holes when the brake disc rotates.

[0006] DE 10 2019 133 772 A1 discloses a vehicle particulate matter collection device in which particulate matter is separated from a moving component. A fluidic separation device generates a directed fluid flow. The fluid flow is directed toward the moving component to separate particulate matter from the moving component. The fluid flow separates a boundary layer containing particulate matter from the moving component. This vehicle particulate matter collection device can be used for collecting particulate matter in the area of ​​a brake.

[0007] DE 10 2020 105 240 A1 discloses a device with a vortex generator for collecting brake dust from a disc brake comprising a brake disc rotating around a rotational axis in a main direction of rotation, a brake caliper, and brake pads supported on the brake caliper and engaging annular braking surfaces of the brake disc during braking. The device comprises a hood adjoining the brake caliper in the main direction of rotation and covering the braking surfaces over an angle of at least 60° around the rotational axis. Together with the brake disc, the hood defines air flow channels for air moved by the rotating brake disc, adjoining the braking gaps between the brake pads and the braking surfaces. Dust separation devices are arranged within the hood.The air flow channels extend in a partially annular shape along the braking surface, and in each of the air flow channels, a vortex generator is arranged at a distance from the respective braking gap, opposite the braking surface adjacent to the air flow channel. The vortex generator acts on the air flowing through the respective air flow channel and swirls it. The swirled air strikes the adjacent braking surface of the brake disc and carries away brake dust that is located on the braking surface, i.e. directly on the braking surface or in a boundary layer of the flowing air close to the braking surface. A relatively large proportion of the brake dust generated by a brake disc remains on the braking surfaces over large circumferential areas adjacent to the braking gaps and can therefore escape from devices for collecting brake dust and yet still reach the environment.This applies even if the free outlet cross-sections are only as small as those required to prevent contact between the respective device and the rotating brake disc. OBJECT OF THE INVENTION

[0008] The invention is based on the object of providing a disc brake with a brake disc from which large portions of the brake dust can be transferred into a brake dust collection device with particularly little effort. SOLUTION

[0009] The object of the invention is achieved by a disc brake having the features of independent claim 1. The dependent claims relate to preferred embodiments of the disc brake according to the invention. DESCRIPTION OF THE INVENTION

[0010] In a disc brake according to the invention with a brake disc that has a virtual main disc plane, a disc hub, and two friction rings that are mounted on the disc hub in a rotationally fixed manner about a rotation axis, arranged at an axial distance from one another to form a cooling gap, and provided with holes, the holes through the friction rings each run at an angle of between 20° and 70° to the main disc plane. All holes through both friction rings run either away from or toward the rotation axis, viewed from the cooling gap.

[0011] In any case, as the brake disc rotates about its axis of rotation, the way the holes run through the friction rings exerts centrifugal forces on the air in the holes. These forces either force the air in the holes out of the cooling gap through the friction rings and through their friction surfaces, or they draw the air away from the friction surfaces through the friction rings and into the cooling gap. In both designs, the air, as it passes through the friction surfaces, carries with it any brake dust present there, including in the form of parts of the flow boundary layers adjacent to the friction surfaces, so that the brake dust can be fed to a brake dust collection device on the disc brake with the air flowing through the holes in the friction rings.

[0012] The fact that the main disc plane of the brake disc is referred to as virtual here is intended to express that the brake disc does not need to have a flat surface or the like that coincides even partially with this main disc plane. The virtual main disc plane can be defined by the centers of pairs of points on the friction surfaces of the two friction rings, each of which lies on a straight line parallel to the axis of rotation. More generally, the main disc plane is the plane that runs centrally between the friction rings and to which the axis of rotation is a surface normal.

[0013] The fact that all of the holes through both friction rings - viewed from the cooling gap - run either away from the axis of rotation or towards the axis of rotation means the following: Due to its angle of between 20° and 70° to the main disc plane, each of the holes has a directional component parallel to the main disc plane. Depending on the design of the disc brake, this directional component parallel to the main disc plane runs largely away from the axis of rotation or towards the axis of rotation and thus has a directional sub-component aligned radially to the axis of rotation. The directional component running parallel to the main disc plane can also have a directional sub-component running tangentially to a virtual circle around the axis of rotation. This means that the holes through the friction rings run towards or away from the axis of rotation.run away from the axis of rotation, not that they run directly away from the axis of rotation or towards the axis of rotation, but only that the distance to the axis of rotation increases or decreases over their course. As a rule, however, the radial directional component is at least as large as the tangential directional component of the directional component parallel to the main axis of the disk. Preferably, the resulting angle between the directional component parallel to the main plane of the disk and a radial to the axis of rotation is much smaller than 45° and lies in a range from 0° to 30° or 15° or 5°. In particular, the holes can each run in a plane spanned by the axis of rotation and a normal to the axis of rotation. Here and elsewhere, any information on the course of the holes refers to their axes.

[0014] The holes can be positioned at an angle of between 30° and 60° or between 40° and 50°, i.e., approximately 45°, to the main disc plane. The diameter of the holes is typically between 0.25 and 1 times the thickness of the friction rings in the direction of the rotation axis. Often, the diameter of the holes is approximately 0.5 times the thickness of the friction rings.

[0015] The axial distance between the friction rings, i.e. the width of the cooling gap, can either decrease or increase with their radial distance from the axis of rotation at an average rate of between 2% and 20%. The width of the cooling gap preferably decreases when - viewed from the cooling gap - all holes through both friction rings run away from the axis of rotation. In this case, the width of the cooling gap can decrease so drastically that a free cross-section of the cooling gap becomes smaller away from the axis of rotation - despite the linear increase in circumference with radius. If - viewed from the cooling gap - all holes through both friction rings run towards the axis of rotation, the width of the cooling gap preferably increases with increasing distance from the axis of rotation.

[0016] The fact that the axial distance between the friction rings decreases with their radial distance from the rotation axis at a rate of ×% means that the axial distance between the friction rings differs by x mm at two points that differ in their radial distance from the rotation axis by 100 mm. The difference in the axial distance is therefore x% of the difference in the radial distance from the rotation axis. If a distance between the friction rings starts at 15 mm at their inner diameter of 16 cm and ends at 7 mm at their outer diameter of 32 cm, it decreases by 8 mm, or 10%, over an 8 cm difference in the radial distance from the rotation axis.

[0017] The change in the axial distance between the friction rings and their radial distance from the rotational axis does not have to be linear, but can take any desired course. The axial distance can also initially decrease and then increase again to form a kind of Venturi nozzle between the friction rings. This allows the air flowing radially outward through the cooling gap to suck air in through the holes in the friction rings, like a jet pump.

[0018] The axial distance between the friction rings, which varies with the radial distance from the axis of rotation, i.e. the width of the cooling gap, which varies in this direction, supports the desired flow of air through the holes in the two friction rings.

[0019] The friction rings of the brake disc are typically connected by webs extending away from the rotational axis. These webs can be straight or blade-shaped. In either case, they ensure that air is pumped through the cooling gap, similar to a rotary or centrifugal pump.

[0020] A brake dust collection device of a disc brake that does not rotate with the brake disc around its axis of rotation may have aerosol collection chambers adjacent to the friction surfaces of the friction rings for collecting an aerosol of brake dust in the air. These aerosol collection chambers may be connected to the brake calipers of the disc brake in the direction of rotation of the friction rings around the axis of rotation.

[0021] It is particularly preferred if cross-sections of the aerosol collection chambers running along the axis of rotation are designed in such a way that the air escaping from the holes in the friction rings creates vortex flows in the aerosol collection chambers around vortex axes running circumferentially around the axis of rotation. These vortex flows can absorb further brake dust from the friction surfaces of the friction rings and thus remove it from the friction rings.

[0022] In this embodiment of the disc brake, in which the holes through the friction rings run away from the axis of rotation as viewed from the cooling gap, a blocking element that does not rotate with the brake disc around the axis of rotation can partially block the cooling gap on the outer circumference of the friction rings. Preferably, the blocking element blocks the cooling gap over such a region of the outer circumference of the friction rings that a resulting back pressure of the air in the cooling gap drives the air in pulses through the holes in the friction rings where the friction rings are free from the brake pads, i.e. in the direction of rotation of the brake disc behind the respective brake caliper. Alternatively or additionally, air can be actively blown into the cooling gap on the inner circumference of the friction rings in such a way that the air is blown out in pulses through the holes in the friction rings at precisely this point.

[0023] On the other hand, in the embodiment of the disc brake according to the invention, in which the holes through the friction rings - viewed from the cooling gap - run towards the axis of rotation, an aerosol collecting chamber for an aerosol of brake dust in air can be arranged on the outer circumference of the friction rings, wherein the cooling gap opens into this aerosol collecting chamber.

[0024] In this embodiment of the disc brake, in which the holes through the friction rings run towards the axis of rotation as viewed from the cooling gap, a blocking element that does not rotate with the brake disc around the axis of rotation can partially block the cooling gap on the inner circumference of the friction rings. Preferably, the blocking element blocks the cooling gap over such a region of the outer circumference of the friction rings that a resulting negative pressure of the air in the cooling gap sucks the air in pulses through the holes in the friction rings where the friction rings are free from the brake pads, i.e. in the direction of rotation of the brake disc behind the respective brake caliper. Alternatively or additionally, air can be actively blown into the cooling gap on the inner circumference of the friction rings in such a way that the air is sucked in pulses through the holes in the friction rings at precisely this point.

[0025] In any case, each aerosol collection chamber may have walls lined with brake dust filter material and / or air outlets covered with brake dust filter material.

[0026] Downstream of the brake dust filter material of the brake dust collection device, a suction device can be provided which actively sucks the air through the brake dust filter material out of the respective aerosol collection chamber and thus separates it from the brake dust remaining in the brake dust filter material.

[0027] Advantageous further developments of the invention emerge from the patent claims, the description and the drawings.

[0028] The advantages of features and combinations of several features mentioned in the description are merely exemplary and can be effective alternatively or cumulatively, without the advantages necessarily having to be achieved by embodiments according to the invention.

[0029] With regard to the disclosure content – ​​not the scope of protection – of the original application documents and the patent, the following applies: Further features can be found in the drawings – in particular the illustrated geometries and the relative dimensions of several components to one another, as well as their relative arrangement and operative connection. The combination of features of different embodiments of the invention or features of different patent claims is also possible, deviating from the chosen references of the patent claims, and is hereby encouraged. This also applies to features that are illustrated in separate drawings or mentioned in their description. These features can also be combined with features of different patent claims.Likewise, features listed in the patent claims may be omitted for further embodiments of the invention, but this does not apply to the independent patent claims of the granted patent.

[0030] The number of features mentioned in the patent claims and the description is to be understood as meaning that exactly this number or a greater number than the stated number is present, without the need for the explicit use of the adverb "at least." Thus, for example, if reference is made to a brake dust collection device, this is to be understood as meaning that exactly one brake dust collection device, two brake dust collection devices, or more brake dust collection devices are present. The features mentioned in the patent claims may be supplemented by further features or may be the only features present in the subject matter of the respective patent claim.

[0031] The reference signs contained in the patent claims do not represent a limitation of the scope of the subject-matter protected by the patent claims. They serve solely to make the patent claims easier to understand. BRIEF DESCRIPTION OF THE CHARACTERS

[0032] In the following, the invention is further explained and described with reference to preferred embodiments shown in the figures. Fig. 1 shows a section through a brake disc of a disc brake according to the invention, taken along its axis of rotation. Fig. 2 is an axial plan view of the brake disc according to Fig. 1, in which a section line II represents the longitudinal section according to Fig. 1. Fig. 3 shows the brake disc according to the Fig. 1 and Fig. 2 in one Fig. 1 corresponding longitudinal section together with a brake dust collection device of the disc brake according to the invention; and Fig. 4 shows another embodiment of the brake disc of another embodiment of the disc brake according to the invention together with a brake dust collecting device of this disc brake in a Fig. 1 and Fig. 3 corresponding longitudinal section. FIGURE DESCRIPTION

[0033] The Fig. 1 and Fig. The brake disc 1 shown in Figure 2 is part of a disc brake 2, which may include further components not shown here, such as a brake calliper and brake pads movably supported thereon. The brake disc is also shown in Figures Fig. 1 and Fig. 2 not shown in full. Shown are a brake disc 1, a disc chamber 3 with a central opening 18, and two friction rings 5 ​​and 6 mounted on the disc chamber so as to rotate about a rotational axis 4 of the brake disc. The friction ring 5 is formed integrally with the disc chamber 3 here, but could also be manufactured separately and then connected to the disc chamber 3. For example, the disc chamber 3 can be made of aluminum, while both friction rings 5 ​​and 6 are made of steel, for example so-called gray cast iron, or a ceramic material. The two friction rings are arranged at an axial distance 8 from one another, forming a cooling gap 7. The axial distance 8 decreases here away from the rotational axis 4, so that the width of the cooling gap 7 decreases away from the rotational axis 4. Not shown is that the distance 8 between the friction rings 5 ​​and 6 is bridged by webs running radially to the rotational axis 4.These webs define the distance 8 and connect the friction rings 5 ​​and 6 to form a rigid unit. In addition, the webs (not shown) cause air located in the cooling gap 7 between the friction rings 5 ​​and 6 to be accelerated away from the axis of rotation 4 by centrifugal forces when the brake disc 1 rotates about its axis of rotation 4, according to the principle of a centrifugal or centrifugal pump. Such acceleration of the air away from the axis of rotation 4 when the brake disc 1 rotates also occurs in holes 9 and 10 that run through the friction rings 5 ​​and 6 because these holes 9 and 10 each run at an angle 19 of approximately 45° to a main disc plane 11 of the brake disc 1, specifically here in such a way that - viewed from the cooling gap 7 - they all run away from the axis of rotation 4. Specifically, all holes 9 and 10 run with their respective axes in planes which - like the drawing plane of . Fig. 1 - from the rotational axis 4 and a normal to the rotational axis 4. When the brake disc 1 rotates about the rotational axis 4, the air is conveyed by the resulting centrifugal forces in the direction of arrows 12 and 13 through the holes 9 and 10 and thus exits through friction surfaces 14 and 15 of the friction rings 5 ​​and 6. The air exiting from the holes 9 and 10 takes along the brake dust located on the friction surfaces 12 and transfers it into a Fig. 1 and Fig. 2 brake dust collection device of the disc brake 2 (not shown). The air entrains, in particular, parts of the flow boundary layers that form on the friction surfaces 14 and 15 of the rotating brake disc 1 and that are heavily laden with brake dust. Reducing the distance 8 and thus the width of the cooling gap 7 away from the rotation axis 4 supports the flow of air through the holes 9 and 10 in the direction of arrows 12 and 13. Additionally, the cooling gap 7 can be blocked on the outer circumference of the friction rings 5 ​​and 6, either by elements that rotate with the brake disc 1 or by elements that do not rotate with the brake disc 1.

[0034] Of the holes 9 in the friction ring 5, Fig. 2 only those are shown which are arranged along the section line II. However, the holes 9 are actually the same as the holes 10 in the Fig. 2 not visible friction ring 6 is arranged distributed over the entire circumference of the friction rings 5 ​​and 6 around the axis of rotation 4. Fig. 2 shows in addition to Fig. 1 mounting holes 16 and an additional axial hole 17 in the disc pot 3, which are arranged distributed around its central opening 18.

[0035] Fig. 3 shows in addition to the longitudinal section according to Fig. 1 a brake dust collection device 20 of the disc brake 2. The brake dust collection device 20 forms aerosol collection chambers 21 and 22 adjacent to the friction surfaces 14 and 15 of the friction rings 5 ​​and 6. These aerosol collection chambers 21 and 22 are intended for aerosols of brake dust in air, which are formed by the air escaping from the holes 9 and 10 in the friction rings 5 ​​and 6 in the direction of arrows 12 and 13. The aerosol collection chambers 21 and 22 can be connected in the direction of rotation of the brake disc 1 about its rotation axis 4 to a brake caliper (not shown here) with brake pads of the disc brake 2 engaging the friction surfaces 14 and 15. In the aerosol collection chambers 21 and 22, the air escaping in the direction of arrows 12 and 13 forms vortex flows 23 and 24, which remove further brake dust from the friction surfaces 14 and 15. The vortex flows 23 and 24 extend around vortex axes 25 and 26, which extend circumferentially around the rotation axis 4.The aerosol collection chambers 21 and 22 are delimited to the outside by a housing 27 of the brake dust collection device 20. The walls 28 and 29 of the housing 27 delimiting the aerosol collection chambers 21 and 22 are lined with brake dust filter material 30. The brake dust filter material 30 spans air outlets 31 and 32 provided in the walls 28 and 29. The vortex flows 23 and 24 in the aerosol collection chambers 21 and 22 transfer the brake dust from the friction surfaces 14 and 15 into the brake dust filter material 30. With a blocking element 33 which, like the housing 27, does not rotate around the axis of rotation 4 together with the brake disc 1, the cooling gap 7 on the outer circumference of the friction rings 5 ​​and 6 is blocked in certain areas, i.e. over such an area of ​​the outer circumference, in order to temporarily generate a dynamic pressure which conveys the air entering the cooling gap 7 from the radial inside, following the brake calliper, in pulses through the holes 9 and 10 in the friction rings 5 ​​and 6.To achieve this, the blocking element 33 may need to be positioned in front of the brake caliper or in the area of ​​the brake caliper in the direction of rotation of the brake disc 2, so that the resulting air blasts occur at the desired location. Additionally, air can be blown radially into the cooling gap 7 to intensify the resulting air blasts.

[0036] Fig. 4 shows an embodiment of the disc brake 2, in which the holes 9 and 10 are formed by the friction rings 5 ​​and 6 with respect to the Fig. 1 and Fig. 3 have an inverse inclination to the friction surfaces 14 and 15 and the rotational axis 4. Viewed from the cooling gap 7, the holes 9 and 10 here therefore do not run away from the rotational axis 4, but towards the rotational axis 4. As a consequence, the air in the holes is conveyed along the arrows 12 and 13 into the cooling gap 7 and thereby takes brake dust accumulating on the friction surfaces 14 and 15 through the holes 9 and 10 into the cooling gap 7. From there, the aerosol of brake dust in air passes into an aerosol collecting chamber 34 in the housing 27 of the brake dust collecting device 20, which aerosol collecting chamber 34 is connected to the cooling gap 7 in the outer circumference of the friction rings 5 ​​and 6. This aerosol collecting chamber 34 is also lined with brake dust filter material 30 and its wall 35 is provided with air outlets 36 which are spanned by the filter material 30. While in the embodiment according to the Fig. 1 to 3, the flow boundary layer loaded with brake dust is blown out at the friction surfaces 14 and 15 of the rotating brake disc 1 through the holes 9 and 10 into the brake dust collecting device 20, the flow boundary layer loaded with brake dust is blown out according to Fig. 4 through the holes 9 and 10 into the cooling gap 7 and passes through this into the brake dust collecting device 20. This effect is promoted by the fact that the cooling gap 7 in the embodiment according to Fig.4 is expanded away from the axis of rotation 4, ie the distance 8 between the friction rings 5 ​​and 6 and the axis of rotation 4 becomes larger. Here, the cooling gap on the inner circumference of the friction rings 5 ​​and 6 can be blocked in some areas with a blocking element which, like the housing 27, does not rotate around the axis of rotation 4 together with the brake disc 1, ie in such a way that a temporary negative pressure is created in the cooling gap 7 following the brake calliper, which sucks the air in bursts through the holes 9 and 10 into the cooling gap 7. LIST OF REFERENCE SYMBOLS 1 brake disc 2 disc brakes 3 disc pot 4 axis of rotation 5 Friction ring 6 friction ring 7 Cooling gap 8 Distance 9 holes 10 holes 11 Main disc level 12 Arrow 13 Arrow 14 Friction surface 15 Friction surface 16 mounting holes 17 Another hole 18 central opening 19 angles 20 Brake dust collection device 21 Aerosol collection chamber 22 Aerosol collection chamber 23 Vortex flow 24 Vortex flow 25 Vortex axis 26 Vortex axis 27 housings 28 Wall 29 Wall 30 brake dust filter material 31 Air outlet 32 Air outlet 33 Blocking element 34 Aerosol collection chamber 35 Wall 36 Air outlet QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 196 41 419 A1

[0004] US 2001 / 0032759 A1

[0005] DE 10 2019 133 772 A1

[0006] DE 10 2020 105 240 A1

[0007]

Claims

[1] Disc brake (2) with a brake disc (1) which - a virtual main disk plane (11), - a disc pot (3) and - two - on the disc pot (3) mounted so as to be non-rotatable about a rotation axis (4), - arranged at an axial distance (8) from one another to form a cooling gap (7) and - has friction rings (5, 6) provided with holes (9, 10), characterized by , - that the holes (9, 10) through the friction rings (5, 6) each run at an angle (19) of between 20° and 70° to the main disc plane (11), - wherein - viewed from the cooling gap (7) - either all holes (9, 10) run through both friction rings (5, 6) away from the axis of rotation (4) - or all holes (9, 10) run through both friction rings (5, 6) towards the axis of rotation (4). [2] Disc brake (2) according to claim 1, characterized by , - that the holes (9, 10) each extend in a plane spanned by the axis of rotation (4) and a normal to the axis of rotation (4) and / or - that the holes (9, 10) each run at an angle (19) between 30° and 60° or between 40° and 50° to the main plane (11) of the disc. [3] Disc brake (2) according to one of the preceding claims, characterized by that the axial distance (8) of the friction rings (5, 6) with their radial distance (8) to the axis of rotation (4) either decreases or increases at an average rate between 2% and 20%. [4] Disc brake (2) according to one of the preceding claims, characterized by that the friction rings (5, 6) are connected to one another by webs extending away from the axis of rotation (4). [5] Disc brake (2) according to one of the preceding claims, characterized by that the cooling gap (7) is partially blocked on the outer circumference and / or on the inner circumference of the friction rings (5, 6). [6] Disc brake (2) according to one of the preceding claims, characterized by that a brake dust collecting device (20) of the disc brake (2) which does not rotate with the brake disc (1) about the axis of rotation (4) has aerosol collecting chambers (21, 22) for an aerosol of brake dust in air, adjacent to friction surfaces (14, 15) of the friction rings (5, 6). [7] Disc brake (2) according to claim 6, characterized by that cross-sections of the aerosol collecting chambers (21, 22) running along the axis of rotation (4) are designed in such a way that air emerging from the holes (9, 10) in the friction rings (5, 6) causes vortex flows (23, 24) around vortex axes (25, 26) running in the circumferential direction around the axis of rotation (4) in the aerosol collecting chambers (21, 22). [8] Disc brake (2) according to claim 6 or 7, characterized bythat a blocking element (33) of the brake dust collecting device (20) which does not rotate with the brake disc (1) around the axis of rotation (4) blocks the cooling gap (7) on the outer circumference of the friction rings (5, 6) in some areas. [9] Disc brake (2) according to one of claims 1 to 6, characterized by that a brake dust collecting device (20) of the disc brake (2) which does not rotate with the brake disc (1) about the axis of rotation (4) has an aerosol collecting chamber (34) for an aerosol of brake dust in air, which aerosol is connected to the cooling gap (7) on the outer circumference of the friction rings (5, 6). [10] Disc brake (2) according to one of claims 7 to 9, characterized by that each aerosol collecting chamber (21, 22, 34) has walls (28, 29, 35) lined with brake dust filter material (30) and / or air outlets (31, 32, 36) spanned with brake dust filter material (30).

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