Drum brake

Abstract

The invention relates to a drum brake (1), in particular for a utility vehicle, having a brake drum (2) which is rotatably mounted about a rotational axis (D), multiple brake linings (3) which are mounted in a receiving area (22) of the brake drum (2) and each of which has a friction lining carrier (32) and a friction lining (31) provided thereon, a brake application device (4) which is rotationally fixed to an armature housing (5) and by means of which the brake linings (3) can be pressed against an inner lateral surface (21) of the brake drum (2), said inner lateral surface being designed as a friction surface, and a cover element (6) which covers an open end face of the brake drum (2) and is mounted in a contact-free manner with respect to the brake drum (2), wherein a collecting material (7) which collects brake dust is provided on or near an end-face edge (23) of the brake drum (2), and the collecting material (7) is positioned between the brake drum (2) and the cover element (6).

Description

[0001] drum brake

[0002] The present invention relates to a drum brake according to the preamble of claim 1.

[0003] Drum brakes of this type feature a cylindrical drum-shaped rotor with friction surfaces arranged on the inside of the rotor, also known as the brake drum. Braking force is generated by brake pads that are pressed against the inner friction surface of the brake drum.

[0004] Such friction brakes generate abrasion of brake pad material on the brake pad and on the inner friction surface of the brake drum, which, if not vacuumed away, escapes into the environment in the form of fine particles.

[0005] In order to avoid such particulate matter pollution caused by the abrasion of such friction material, it is desirable to develop technical solutions for friction brakes for commercial vehicles that are able to minimize brake dust, in particular the particulate matter content of brake dust, and ideally prevent its emission into the environment.

[0006] Drum brakes, unlike disc brakes, have the advantage that the brake shoes are located inside the brake drum, making them easy to encapsulate. This keeps most of the predominantly coarser wear debris inside the drum brake and can be removed and disposed of during service. This removal is usually done with standard vacuum cleaners.

[0007] Since, due to the rotational relative movement, gaps inevitably occur between components moving relative to one another in drum brakes, particles, especially fine particles, can continue to escape from the interior of the brake drum through these gaps.

[0008] A drum brake of this type is known, for example, from DE 10 2016 117 778 A1. In this drum brake, an open end of the brake drum is covered with a cover. This cover contains an opening into which a suction device equipped with a dust extraction unit is connected, which has proven itself effective in practice.

[0009] The object of the present invention is to provide a drum brake with which a further improvement can be achieved with regard to preventing the escape of brake dust.

[0010] This object is achieved by a drum brake having the features of claim 1.

[0011] The drum brake according to the invention, in particular for a commercial vehicle, has a brake drum mounted so as to be rotatable about a rotation axis and a plurality of brake pads mounted in a receiving space of the brake drum, each with a friction pad carrier and a friction pad arranged thereon.

[0012] An application device is arranged on an armature housing of the drum brake, with which the brake pads can be pressed against an inner surface of the brake drum designed as a friction surface.

[0013] The drum brake further comprises a cover element covering at least a partial surface of an open end face of the brake drum and mounted in the region of the open end face of the brake drum without contact, forming an air gap to the brake drum.

[0014] A brake dust collecting material is arranged on or near a front edge of the brake drum, the collecting material being arranged between the brake drum and the cover element.

[0015] With a drum brake designed in this way, an improvement in preventing the escape of brake dust is now achieved by arranging the collecting material on or near a front edge of the brake drum, since the brake dust is trapped in the collecting material and thus the escape of the brake dust into the environment is at least largely prevented.

[0016] The particle size of the particulate matter produced during braking, which should not be released for environmental and health reasons, ranges from 2.5 nm to 10 nm. Solid particles of this size can exhibit dipole interactions (van der Waals forces) at very close distances (< 100 nm) to adjacent surfaces. These adhesive forces are many times greater than the weight of the particles. The present invention utilizes this effect to collect brake dust within a drum brake.

[0017] Advantageous embodiments of the invention are the subject of the subclaims.

[0018] According to an advantageous embodiment, a recess is formed on or near a front edge of the brake drum, in which the brake dust collecting material is arranged.

[0019] The recess with the collecting material arranged therein is covered by the cover element.

[0020] Such a cover plate is, on the one hand, stable enough for the harsh environment, simple and cost-effective to manufacture and can be easily attached to the brake drum or the armature housing.

[0021] According to an advantageous embodiment, the cover element is designed as an annular cover plate.

[0022] According to a further preferred embodiment, the cover element has a cover area which extends radially to the axis of rotation from the front edge of the brake drum in the direction of the axis of rotation, as well as a collecting area which partially encompasses the collecting material.

[0023] This collection area also serves to direct the particle flow of brake dust, which collects in the collection material located there after entering the collection area of ​​the cover element.

[0024] Furthermore, the kinetic energy of the particles is also slowed down in the collection area.

[0025] According to a further preferred embodiment, the cover element has a radially inwardly curved region adjacent to the collecting region, which is shaped parallel to an outer contour of the brake drum. According to a preferred embodiment, the recess accommodating the collecting material is formed as a groove in the front edge of the brake drum.

[0026] Such a groove can be easily inserted into the front side of the brake drum.

[0027] According to a further embodiment, the recess is formed as a material cutout formed in a transition region between the front edge of the brake drum and an outer surface of the drum casing. The collecting material is accommodated in the material cutout, with the collecting material being accommodated in a space defined by the collecting region of the cover element and a contact surface of the brake drum.

[0028] The introduction of such a material recess can also be easily carried out in the brake drum.

[0029] According to a further preferred embodiment, the radially inwardly curved portion of the cover element extends into a groove-shaped recess in the material recess of the brake drum. The receiving portion and the holding portion are preferably designed as tongues extending radially to the rotational axis of the brake drum.

[0030] Preferably, an annular bead extends radially outward from the contact surface of the brake drum. This bead primarily serves to guide the air flow enriched with brake dust.

[0031] The cover element is preferably attached to the armature housing.

[0032] According to a further preferred embodiment, at least one suction connection is arranged on the cover element.

[0033] In principle, it is also conceivable to attach the cover element to the brake drum.

[0034] According to another preferred embodiment, the collecting material is fixed, in particular glued, to the cover element. According to another embodiment, the collecting material at least partially, in particular completely, covers a surface facing the front edge of the brake drum.

[0035] The object is also achieved by a drum brake in which, alternatively or in addition to the arrangement of the collecting material in the recess covered by the cover element, brake dust collecting material is arranged between adjacent brake pads on or near the front edge of the brake drum, viewed in the circumferential direction.

[0036] According to an advantageous embodiment, the collecting material is held in holders attached to the anchor housing. In an advantageous further development, these holders are designed as wire mesh.

[0037] In a preferred embodiment, the collecting material consists of one or more of the following materials: metal wool, wire mesh, porous metal foam, in particular foamed aluminum, fabric hose filled with a granulate.

[0038] In the metal wool version, this preferably has a wire thickness between 30 pm and 120 pm, with a specific weight between 800 g / m 2 and 1300 g / m 2 on.

[0039] Through an advantageous geometric design of the interface between the brake drum and the cover element, the air flow is transformed into a turbulent flow. This directs the particles into contact with the capture material. When bridging the critical distance to the metal wool, or to particles already attached to the metal wool, the enormous adhesive forces relative to the weight of the particles take effect, and the particles are deposited on the surface of the metal wool or form conglomerates with the already attached particles. Metal wool is a particularly advantageous material because its metal, particularly steel, threads themselves have a very small diameter, as described above. The material can therefore provide a very large surface area with a small volume thanks to its multi-layered structure.

[0040] Preferred embodiments are explained in more detail below with reference to the accompanying drawings. In the drawings: Fig. 1 shows a schematic isometric view of a variant of a drum brake according to the invention,

[0041] Fig. 2 is a sectional view through a preferred embodiment of the drum brake,

[0042] Fig. 3 is an isometric enlarged detail of a wall of a brake drum of the drum brake according to Figure 1 with a cover element and collecting material arranged thereon,

[0043] Figures

[0044] 4 to 6 further alternative design variants of such a cover element as well as designs of the wall of the brake drum,

[0045] Fig. 7 is a schematic isometric view of a further embodiment of a drum brake according to the invention with a hidden brake drum,

[0046] Fig. 8 is a side view of the drum brake shown in Fig. 7 to show the arrangement of brake pads and the collecting material arranged therebetween,

[0047] Fig. 9 is a sectional view through a region of the wall of the brake drum with a cover element and collecting material arranged thereon,

[0048] Fig. 10 is a sectional view of the drum brake through a cutting plane designated X in Fig. 9,

[0049] Fig. 11 is a side view of the drum brake to show a cutting plane for Fig. 12,

[0050] Fig. 12 is a sectional view through the section plane shown in Fig. 11 to show the collecting material arranged between brake pads,

[0051] Fig. 13 is a representation corresponding to Fig. 10 of a further embodiment of a drum brake according to the invention, Figs. 14 and 15 are views of the drum brake according to Fig. 13 corresponding to Figs. 9 and 10,

[0052] Fig. 16 is a further sectional view of the drum brake corresponding to Fig. 12. Fig. 13,

[0053] Fig. 17 is a schematic isometric view of the cover element with brackets accommodated therein and brackets for collecting material arranged between the brake pads,

[0054] Fig. 18 is an isometric view of a wire mesh holder for fixing the collecting material between the brake pads and

[0055] Fig. 19 is an isometric detail view of a ring-shaped wire mesh for use on the inside of the cover element.

[0056] In the following description of the figures, terms such as top, bottom, left, right, front, rear, etc., refer exclusively to the exemplary representation and position of the drum brake, brake drum, catch material, cover element, and the like chosen in the respective figures. These terms are not to be understood as limiting; i.e., these references may change due to different operating positions or the mirror-symmetrical design, etc.

[0057] In Figure 1, reference numeral 1 denotes an embodiment of a preferably pneumatically or electromechanically driven drum brake according to the invention, particularly for use in a commercial vehicle. The drum brake 1 has a brake drum 2 mounted for rotation about a rotation axis D, which is rotationally connected to a hub (not shown here), preferably of a commercial vehicle, via an armature housing 5.

[0058] In a space radially inside the outer wall of the brake drum 2, a plurality of brake pads 3 are mounted in a receiving space of the brake drum 2, each with a respective friction lining carrier 32 and a friction lining 31 arranged thereon. The brake pads 3 are arranged with their friction linings 31 facing an inner surface 21 of the brake drum 2, as shown by way of example in Figure 2.

[0059] As further shown in Figure 2, an application device 4 with a wedge ring 41 which can be moved on a cylinder sleeve 51 of the armature housing 5 parallel to the rotational axis D of the brake drum 2 is arranged on the armature housing 5, with which wedge ring the brake pads 3 can be pressed onto the inner surface 21 of the brake drum 2, which is designed as a friction surface, radially to the rotational axis D of the brake drum 2 (direction r shown in Figure 1).

[0060] To transmit the movement of the wedge ring 41 to the brake pads 3, a respective pressure wedge 34 is arranged as part of a respective brake pad 3 on a side of the friction pad carrier 32 facing away from the friction pad 31. The pressure wedge 34 is connected to the friction pad carrier 32 via a pressure piston 35.

[0061] The pressure wedge 34 rests on a pressure surface of the wedge ring 41, as can be seen in Figure 2.

[0062] The wedge ring 41 can be displaced, for example via a service brake piston 92, parallel to the rotation axis D of the brake drum 2 from a non-braking position into a braking position in a direction z, shown in Figure 1.

[0063] A slide 42 with a plurality of rolling elements 43 is arranged between the wedge ring 41 and the pressure wedge 34 of the brake pad 3 in order to reduce the friction between the pressure surface of the wedge ring 41 and the pressure wedge 34 of the brake pad 3.

[0064] In order to carry out the radial pressing movement of the brake shoes 3 against the inner surface 21 of the brake drum 2 in the preferred embodiment shown in Figure 2, the application device 4 has a brake cylinder arrangement 9 arranged in the receiving space 29 of the brake drum 2 on the armature housing 5 in a rotationally fixed manner.

[0065] The brake cylinder arrangement 9 has a housing 91 fixedly fastened to the armature housing 5 in the receiving space 29 of the brake drum 2.

[0066] The service brake piston 92 is arranged displaceably relative to this housing 91 parallel to the rotational axis D of the brake drum 2. Furthermore, the brake cylinder arrangement 9 has a parking brake piston 93, which is displaceable relative to the housing 91 parallel to the rotational axis D of the brake drum 2 and can be subjected to the spring force of a spring element 96 via an intermediate plate 95.

[0067] The spring element 96 is preferably designed as a disc spring, as shown by way of example in Figure 2.

[0068] The brake cylinder arrangement 9 further comprises a plurality of tappets 94 which serve to transmit a movement of the parking brake piston 93 to the service brake piston 92.

[0069] Furthermore, compressed air supplies are provided, which open firstly into a service brake pressure chamber between the housing 91 and the service brake piston 92 and secondly into a parking brake pressure chamber 97 between the housing 91 and the parking brake piston 93.

[0070] Important for the actuation of the brake shoes 3 is always the movement of the service brake piston 92, which in the event of an intentional throttling of the speed of the commercial vehicle, a so-called service braking operation, is brought about by the supply of compressed air into the service brake pressure chamber.

[0071] In the event of an intentional brake application, which serves to prevent the commercial vehicle from accidentally rolling away in a parking situation, compressed air present in the parking brake pressure chamber 97 during parking operation is released from the parking brake pressure chamber 97, resulting in a displacement of the parking brake piston 93 toward the service brake piston 92. The displacement is caused by the force exerted by the spring element 96 on a rear side of the parking brake piston 93 facing away from the service brake piston 92.

[0072] While in the embodiment shown in Figure 2, the application device 4 is designed such that the brake pads can be moved radially to the rotational axis D in the direction of the inner surface 21 of the brake drum 2, it is also conceivable to arrange the brake pads on one or more subassemblies that can be pivoted against the inner surface 21 of the brake drum 2 via a so-called S-cam, as is the case with so-called simplex drum brakes. In such simplex drum brakes, the application device is formed by the S-cam and the subassembly that can be moved by it.

[0073] As shown in Figure 2 and in Figures 3 to 6, at least a partial surface of an open end face of the brake drum 2 is covered with a cover element 6 mounted in the region of the open end face of the brake drum 2 without contact, forming an air gap 11.

[0074] A brake dust collecting material is arranged on or near a front edge of the brake drum, the collecting material being arranged between the brake drum and the cover element.

[0075] In the embodiment shown in Figure 2, the cover element 6 also covers a recess formed on or near a front edge 23 of the brake drum 2, in which the brake dust collecting material 7 is arranged.

[0076] The cover element 6 is preferably designed as an annular cover plate.

[0077] The air gap 11 is also preferably annular and extends, as shown by way of example in Figures 3 to 6, between the front edge of the brake drum 2 and the inner surface of the cover element 6 facing it.

[0078] In the embodiment shown in Figure 3, the cover plate has a cover region 61 extending over a portion of the front edge 23 of the brake drum 2 and a region radially within the inner surface 21 of the brake drum 2, which cover region extends radially to the axis of rotation D from the front edge 23 of the brake drum 2 in the direction of the axis of rotation D, as well as a collecting region 62 partially encompassing the collecting material 7.

[0079] This collecting area 62 extends into a recess formed as a groove 24 in the front edge 23 of the brake drum 2, in which the collecting material 7 is received.

[0080] The cover element 6 is, as further illustrated in Figures 1 and 2, preferably fastened to the armature housing 5 with screws. It is also conceivable to fix the cover element 6 to the brake drum 2, in particular in the region of an outer surface of the brake drum 2.

[0081] By covering the gap between the armature housing 5 and the inner surface 21 of the brake drum 2, in which the brake shoes are movably arranged, with the cover element 6, brake dust generated during a braking operation cannot escape from the interior of the brake drum 2 into the wheel house of a vehicle wheel, but is largely sucked out of the interior of the brake drum 2 directly via a suction device.

[0082] For this purpose, in the embodiment variant shown here, a suction connection 8 with a suction pipe 81 and a retaining lip 82 is provided on the cover element 6, onto which a connecting hose of the suction device (not shown) can be plugged.

[0083] A further part of the brake dust passes through a remaining gap between the cover area 61 of the cover element 6 and the front edge 23 of the brake drum 2, with an air flow guided through the underside of the cover element 6 facing the front edge 23 of the brake drum 2, into the collecting area 62 of the cover element 6.

[0084] The collecting material 7 arranged in the collecting area 62 allows the brake dust that has entered this area to be collected in the collecting material 7 and, in the event of servicing, the collecting material 7 filled with brake dust can be replaced.

[0085] The collecting material 7 can be shaped as a filter mat and preferably consists of metal wool, a wire mesh or a porous metal foam, in particular a foamed aluminum.

[0086] It is also conceivable to design the collecting material in the form of a fabric tube filled with granules.

[0087] The collecting material 7 is preferably held, preferably clamped, to the cover element 6 by the shape of the collecting region 62. The collecting regions 62 are preferably designed as a slightly bent extension of the cover region 61. It is also conceivable to additionally glue the collecting material 7 to the cover element 6.

[0088] In the embodiments shown in Figures 4 to 6, the recess on the brake drum 2 is designed as a material recess 25 introduced into a transition region between the front edge 23 and an outer surface 22 of the brake drum 2, in which the collecting material 7 is received.

[0089] The collecting material 7 is here accommodated in a space delimited by the collecting area 62 of the cover element 6 and a contact surface 26 of the brake drum 2.

[0090] The collecting area 62 is preferably pocket-shaped in cross-section, so that the collecting material 7 is received in this pocket, preferably fixed to the inner surface of the pocket. The air gap 11 preferably runs between the collecting material 7 and the contact surface 26 of the brake drum 2.

[0091] Furthermore, in the embodiments shown in Figures 4 to 6, the cover element 6 has a radially inwardly bent region 63 which adjoins the collecting region 62 and extends in the direction of a groove-shaped recess 27 in the region of the material recess 25 of the brake drum 2 and thus enables further turbulence of an air flow flowing through the collecting region 62 from the air gap 11.

[0092] As further shown in Figures 5 and 6, an annular bead 28 extends radially outwards from the contact surface 26 of the brake drum 2 in order to positively influence the air flow enriched with the brake dust.

[0093] In the embodiment shown in Figure 5, this bead 28 is formed close to the groove-shaped recess 27.

[0094] In the embodiment shown in Figure 6, this bead 28 extends radially outwards as an extension of the front edge 23 of the brake drum 2.

[0095] In all embodiments shown, the collecting material 7 is designed in such a way that it occupies as completely as possible the space between the inside of the collecting area 62 and the respective contact surface 26 in the area of ​​the groove 24 or the material recess 25 of the brake drum 2.

[0096] Overall, the cover element 6 with the collecting material 7 arranged thereon can be easily installed on the brake drum 2 and can be attached to the brake drum 2 quickly and easily.

[0097] The use of such a cover element 6 with collecting material 7 arranged thereon contributes in particular to reducing the environmental pollution caused by brake dust and to extending the service life of the drum brake.

[0098] In principle, it is also conceivable for the cover element to be arranged on a brake drum without a recess in the area of ​​the front edge 23 of the brake drum 2, in which the collecting material 7 is accommodated, for example, between the brake drum 2 and a flanged area or an area of ​​the cover element 6 which is bent towards the brake drum 2.

[0099] Figures 7 to 19 show further embodiments of drum brakes according to the invention.

[0100] As shown in Figures 7, 8, 12, 13, 16 and 17, in this embodiment, brake dust collecting material 7 is also arranged between adjacent brake pads 3, viewed in the circumferential direction of the brake drum.

[0101] The arrangement of the collecting material 7 between adjacent brake pads 3 represents a further significant improvement with regard to the collection of the fine brake dust generated during braking, since the brake dust particles are thrown away tangentially to the direction of rotation of the brake drum 2 when the friction material is pressed against the friction surface of the brake drum 2.

[0102] The brake dust particles are not released directly into the environment, but are first thrown into the space between the armature housing 5, brake drum 2 and cover element 6.

[0103] Depending on the available space between adjacent brake pads, correspondingly large areas are provided for the collecting material 7. The collecting material 7 arranged between adjacent brake pads 3 is preferably held on brackets 14, which in turn are attached to the armature housing 5.

[0104] As can be further seen in Figures 8 and 12, the holders 14 here consist of webs through which bolts extend parallel to the axis of rotation of the brake drum 2, which bolts are passed through the collecting material 7.

[0105] The radial thickness of the collecting material 7 arranged in the areas between the brake pads 3 is dimensioned such that it makes maximum use of the space between the brake pads 3, the armature housing 5 and the brake drum 2.

[0106] As further shown in Figures 9 and 10, in the embodiment variant shown here, the collecting material 7 arranged under the cover element 6 is not only used in the area of ​​the groove-shaped recess of the material recess 25 of the brake drum 2, but in the entire U-shaped cross section of the cover element 6, wherein the axial thickness of the collecting material 7 varies depending on the available space.

[0107] Thus, a greater axial thickness is reinforced, particularly in the areas not occupied by the brake pads 3, as shown in Fig. 10.

[0108] The collecting material 7 is arranged on the surface facing the front edge 23 of the brake drum 2, at least partially, and in the embodiment shown, completely covering the surface facing the front edge 23 of the brake drum 2.

[0109] In the embodiment shown in Figures 13 to 19, which essentially corresponds to the embodiment shown in Figures 7 to 12, the collecting material 7 is fixed by holders 12, 13, 14, which are at least partially designed as a wire mesh, as shown in Figures 17 to 19.

[0110] If the collecting material 7 is made of metal wool, it preferably has a wire thickness between 30 pm and 120 pm, with a specific weight between 800 g / m 2 and 1300 g / m 2 The use of steel wool as the collecting material 7 is particularly advantageous because, due to its very small diameter, the steel threads of this steel wool provide a very large surface area with a small volume. Furthermore, steel wool is very heat-resistant and, in terms of abrasion, virtually material-neutral, since the brake drum 2 itself is also made of an iron-containing material.

[0111] List of reference symbols

[0112] 1 drum brake

[0113] 2 brake drums

[0114] 21 Shell inner surface

[0115] 22 Outer shell surface

[0116] 23 Edge

[0117] 24 grooves

[0118] 25 Material recess

[0119] 26 contact surface

[0120] 27 recess

[0121] 28 bulge

[0122] 29 Recording room

[0123] 3 brake shoes

[0124] 31 Friction lining

[0125] 32 friction lining carriers

[0126] 33 Friction surface

[0127] 34 Pressure wedge

[0128] 35 printing stamps

[0129] 4 clamping device

[0130] 41 wedge ring

[0131] 42 sleds

[0132] 43 rolling elements

[0133] 5 armature housing

[0134] 51 Cylinder sleeve

[0135] 6 Cover element

[0136] 61 Coverage area

[0137] 62 Reception area

[0138] 63 Area

[0139] 7 Collection material 8 Suction connection

[0140] 81 Suction pipe

[0141] 82 retaining lip

[0142] 9 Brake cylinder arrangement

[0143] 91 housings

[0144] 92 service brake pistons

[0145] 93 parking brake piston

[0146] 94 tappets

[0147] 95 intermediate plate

[0148] 96 spring element

[0149] 97 Parking brake pressure chamber

[0150] 10 Brake dust collection device

[0151] 11 Air gap

[0152] 12 Bracket

[0153] 13 Bracket

[0154] 14 Bracket

[0155] D axis of rotation

[0156] R, z direction

Claims

Claims 1 . Drum brake (1 ), in particular for a commercial vehicle, comprising - a brake drum (2) mounted so as to be rotatable about an axis of rotation (D), - a plurality of brake pads (3) mounted in a receiving space (22) of the brake drum (2), each with a friction pad carrier (32) and a friction pad (31) arranged thereon, - an application device (4) arranged on an armature housing (5) in a rotationally fixed manner, with which the brake pads (3) can be pressed against an inner surface (21) of the brake drum (2) designed as a friction surface, - a cover element (6) covering at least a partial surface of an open end face of the brake drum (2) and mounted in the region of the open end face of the brake drum (2) without contact, forming an air gap (11) to the brake drum (2), characterized in that - a brake dust collecting material (7) is arranged on or near a front edge (23) of the brake drum (2), - wherein the collecting material (7) is arranged between the brake drum (2) and the cover element (6).

2. Drum brake (1) according to claim 1, characterized in that a recess is formed on the brake drum (2) at or near the front edge (23) of the brake drum (2), in which recess the brake dust collecting material (7) is arranged, wherein the recess with the collecting material (7) arranged therein is covered by the cover element (6).

3. Drum brake (1) according to claim 1 or 2, characterized in that the cover element (6) is designed as an annular cover plate.

4. Drum brake (1) according to one of the preceding claims, characterized in that the cover element (6) has a cover region (61) which extends radially to the axis of rotation (D) from the front edge (23) of the brake drum (2) in the direction of the axis of rotation (D), and a collecting region (62) which partially encompasses the collecting material (7).

5. Drum brake (1) according to claim 4, characterized in that the cover element (6) has a collecting area (62) adjoining radially inwardly bent region (63) which is shaped parallel to an outer contour of the brake drum (2).

6. Drum brake (1) according to one of claims 2 to 5, characterized in that the recess is designed as a groove (24) made in the front edge (23) of the brake drum (2), in which the collecting material (7) is received.

7. Drum brake (1) according to one of claims 2 to 5, characterized in that the recess is designed as a material recess (25) introduced into a transition region between the front edge (23) and an outer surface (22) of the brake drum (2), in which the collecting material (7) is received, wherein the collecting material (7) is received in a space delimited by the collecting region (62) of the cover element (6) and a contact surface (26) of the brake drum (2).

8. Drum brake (1) according to one of claims 5 to 7, characterized in that the radially inwardly bent region (63) of the cover element (6) projects into a groove-shaped recess (27) of the material recess (25) of the brake drum (2).

9. Drum brake (1) according to claim 7 or 8, characterized in that an annular bead (28) extends radially outwards from the contact surface (26) of the brake drum (2).

10. Drum brake (1) according to one of the preceding claims, characterized in that the cover element (6) is fastened to the armature housing (5).

11. Drum brake (1) according to one of the preceding claims, characterized in that at least one suction connection (8) is arranged on the cover element (6).

12. Drum brake (1) according to one of the preceding claims, characterized in that the cover element (6) is fastened to the brake drum (2).

13. Drum brake (1) according to one of the preceding claims, characterized in that the collecting material (7) is fixed, in particular glued, to the cover element (6).

14. Drum brake (1) according to one of the preceding claims, characterized in that the collecting material (7) at least partially, in particular completely, covers a surface facing the front edge (23) of the brake drum (2).

15. Drum brake (1) according to one of the preceding claims or according to the preamble of claim 1, characterized in that, viewed in the circumferential direction, brake dust collecting material (7) is arranged between adjacent brake pads (3).

16. Drum brake (1) according to one of the preceding claims, characterized in that the collecting material (7) is held in holders (12, 13, 14) fastened to the armature housing (5).

17. Drum brake (1) according to claim 16, characterized in that the holders (12, 13, 14) are at least partially designed as a wire mesh.

18. Drum brake (1) according to one of the preceding claims, characterized in that the collecting material (7) consists of one or more of the following materials: metal wool, wire mesh, porous metal foam, in particular foamed aluminum, fabric hose filled with a granulate.

19. Drum brake (1) according to claim 18, characterized in that the metal wool has a wire thickness between 30 pm and 120 pm, with a specific weight between 800 g / m 2 and 1300 g / m 2 has.

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