Brake lining for a drum brake, and drum brake

Abstract

A brake lining (3, 130, 230) for a radially actuatable drum brake (1) of a utility vehicle has a lining support (32, 132, 232), at least one friction lining (31, 131, 231), said friction lining being provided on the lining support (32, 132, 232) and having a friction surface which is convex in the shape of a circular arc segment in the circumferential direction, and a pressure piece (7, 170, 270) which is secured to the lining support (32, 132, 232), said pressure piece (7, 170, 270) being positively and / or frictionally held in the radial direction with the aid of at least one holding element. The invention also relates to a drum brake.

Description

[0001] Brake lining for a drum brake and drum brake

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

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

[0004] According to current technology, in drum brakes for commercial vehicles, the applied actuating force is usually amplified by means of an S-cam in order to generate the necessary braking torques.

[0005] In the drum brakes of the type considered here, whose force transmission is designed such that a force introduced axially to the axis of rotation is amplified by its deflection so that the reaction force acts radially on the friction surface of the brake drum, the brake linings are pressed against by means of a wedge that can be moved in the direction of the axis of rotation.

[0006] The reaction force can be divided by actuating several pressure pieces.

[0007] Since the brake linings are distributed over the full 360° of the inner circumference of the brake drum in this type of drum brake, no position can be found where the brake linings can be secured in a lining recess of the drum brake using gravity. Because of the high temperature levels in the drum brake due to the shielding of the brake drum, a spring-loaded system with so-called lining return springs is difficult to implement, as the spring elements tend to overheat and burn out.

[0008] The object of the present invention is to implement the most rigid possible connection between the brake linings and the force-transmitting components for pressing the brake linings against the inner surface of the brake drum.

[0009] The problem is solved by a brake lining for a drum brake having the features of claim 1. The problem is further solved by a drum brake having the features of claim 18.

[0010] The brake lining according to the invention for a radially actuated drum brake of a commercial vehicle comprises a lining carrier, at least one friction lining arranged on the lining carrier with a friction surface shaped in a circular arc segment in a circumferential direction, and a pressure piece attached to the lining carrier. The pressure piece is held in the radial direction by means of at least one retaining element by means of a positive and / or frictional engagement.

[0011] By securing the pressure piece to the lining carrier in a radial direction using at least one retaining element in a form-fit and / or friction-fit manner, it is possible to design the force-transmitting components of the drum brake acting on the pressure piece in a more cost-effective and lighter manner, since these are primarily subjected to compressive stresses and transverse forces are avoided by the radial mounting.

[0012] Furthermore, the rigid connection prevents residual friction torque and / or NVH (noise, vibration, and harshness) problems. The connection is vibration-resistant to ensure that the friction lining does not come into contact with the brake drum when the drum brake is not engaged. Accordingly, the connection is preferably designed to withstand vibration loads of up to 30g.

[0013] Furthermore, the brake lining and drum brake according to the invention ensure the simplest possible brake lining replacement. This is advantageous because several brake lining replacements are usually necessary over the service life of a commercial vehicle drum brake.

[0014] Advantageous embodiments of the invention are the subject of the dependent claims.

[0015] According to an advantageous embodiment, the pressure piece is free of play in the radial direction and held with play in the circumferential direction.

[0016] This allows for the avoidance of lateral forces acting on the pressure piece.

[0017] According to a first preferred embodiment, a pin projects radially from a side of the friction lining facing away from the friction lining. The pressure piece has a recess on an end face facing the friction lining to receive the pin. The retaining element is designed as a slotted bushing encompassing the pin or as a snap ring encompassing the pin.

[0018] This allows for extremely simple mounting of the pressure piece on the pad carrier.

[0019] In an advantageous embodiment, a groove is formed on an outer circumference of the pin and / or an inner circumferential wall of a recess of the pressure piece that receives the pin, in which the bushing or snap ring is partially inserted.

[0020] The bushing or snap ring is preferably used to form an interference fit between the pin and the recess of the pressure piece.

[0021] Such a press fit enables an extremely vibration-resistant connection between the pressure piece and the pad carrier.

[0022] According to an alternative design variant, the pressure piece has a pressure piece neck extending in the radial direction and a pressure piece head whose end face rests against the lining carrier.

[0023] In an advantageous further development, a pressure piece receptacle is formed in a rear side of the lining carrier facing away from the friction lining, in particular in the form of a recess adapted to the circumference of the pressure piece head.

[0024] This allows for precise, and in particular centered, positioning of the pressure piece on the coating carrier.

[0025] According to a first preferred embodiment, at least one retaining element designed as a retaining bolt is held on the pad carrier to fix this pressure piece in such a way that it presses the pressure piece head against the pad carrier. The retaining bolt is preferably aligned parallel to the end face of the pressure piece head, in particular in the circumferential direction.

[0026] The at least one retaining bolt is preferably rotatably mounted on the pad carrier about its longitudinal axis and is provided with a flattened section. Such a flattened section enables particularly easy mounting of the pressure piece to the pad carrier by rotating the retaining bolt with the flattened section for mounting, so that the flattened section maximizes the gap for inserting the pressure piece.

[0027] After the pressure piece has been fitted, the retaining bolt with the flattened section is turned in the opposite direction, which causes the pressure piece head to be pressed against the back of the pad carrier.

[0028] It is particularly advantageous if the retaining bolt can be fixed in its clamping position, pressing the pressure piece head against the lining carrier.

[0029] According to a preferred embodiment, the retaining bolt can be fixed in its clamping position, which presses the pressure piece head against the pad carrier, by a threaded pin that can be screwed into a threaded bore of the pad carrier.

[0030] This ensures an extremely reliable, play-free connection between the pressure piece and the lining carrier in the radial direction. The radial direction corresponds to the pressure direction of the brake lining against the inner surface of the brake drum.

[0031] Simultaneously, this circumferential connection allows the brake lining to slide around the brake drum. For this purpose, the longitudinal axis of the retaining bolt(s) is aligned so that it runs along the circumference of the brake drum.

[0032] According to a further advantageous embodiment, in which a pin projects radially from a side of the lining carrier facing away from the friction lining and the pressure piece has a recess on an end face facing the lining carrier to receive the pin, the retaining element is designed as a turnbuckle that encompasses the pin and can be fixed in the recess of the pressure piece to form a bayonet-like connection.

[0033] This type of connection is also characterized by the fact that the mounting and dismounting of the lining carrier with the friction lining attached to it is particularly simple. In an advantageous further development of this embodiment, the turnbuckle can be fixed in an undercut of the pressure piece head in the direction of the longitudinal extension of the pin.

[0034] The pin preferably has a projection that can be engaged by the turnbuckle.

[0035] In a further preferred embodiment, the turnbuckle has a guiding edge inclined at an acute angle to the longitudinal axis of the pin for introducing the pin into an undercut in an inner wall of the turnbuckle.

[0036] This allows for very simple mounting of the pad carrier with the friction lining attached to it on the pressure piece.

[0037] For the equally simple disassembly of the lining carrier with the friction lining attached to it, a further advantageous development is the undercut of the turnbuckle designed as a locking edge inclined at an obtuse angle to the longitudinal axis of the pin.

[0038] According to a further embodiment, the turnbuckle has a pressure surface against which a clamping element, preferably in the form of a compression spring, is mounted in the pressure piece head, wherein the clamping element exerts a torque in the mounted state of the pin, which holds the turnbuckle in the back cut of the pressure piece and in engagement with the projection of the pin.

[0039] The radially actuated drum brake according to the invention for a commercial vehicle has a brake drum rotatably mounted about an axis of rotation and at least two brake linings mounted in a receiving space of the brake drum.

[0040] The drum brake further comprises an armature housing with a clamping device fixed to it in a rotationally fixed manner. This clamping device has a wedge ring that is slidable on a cylindrical sleeve of the armature housing parallel to the axis of rotation of the brake drum. This wedge ring allows the brake linings to be pressed radially against the inner surface of the brake drum, relative to the axis of rotation of the brake drum. The brake linings are designed as described above.

[0041] Preferred embodiments are explained in more detail below with reference to the accompanying drawings. Figure 1 shows a schematic isometric view of an embodiment of a drum brake according to the invention.

[0042] Fig. 2 is a sectional view of the drum brake shown in Fig. 1, without showing the brake drum.

[0043] Fig. 3 shows a sectional view of a first embodiment of a brake pad according to the invention with a retaining element designed as a slotted bushing between the pad carrier and the pressure piece.

[0044] Fig. 4 shows a close-up of the embodiment of the brake pad according to the invention shown in Figure 3 with an alternatively designed bushing.

[0045] Fig. 5 shows a representation corresponding to Figure 3 of a further variant with a retaining element designed as a snap ring between the lining carrier and the pressure piece,

[0046] Fig. 6 shows a schematic isometric view of an alternative embodiment of a brake pad according to the invention with a retaining element designed as a retaining bolt between the pad carrier and the pressure piece.

[0047] Fig. 7 shows an exploded view of the embodiment according to Figure 6,

[0048] Fig. 8 shows a top view of the reverse side of the brake pad shown in Figs. 6 and 7, facing away from the friction lining.

[0049] Fig. 9 shows a side view of the brake pad shown in Figs. 6 and 7,

[0050] Fig. 10 shows a sectional view of the brake pad shown in Figs. 6 and 7 in a section plane labelled X in Fig. 9.

[0051] Fig. 11 shows a schematic isometric view of a further alternative embodiment of a brake pad according to the invention with a retaining element designed as a turnbuckle between the pad carrier and the pressure piece; Fig. 12 shows an exploded view of the embodiment according to Figure 11.

[0052] Fig. 13 shows a side sectional view of the brake pad shown in Fig. 11,

[0053] Fig. 14 shows a sectional view through the brake pad shown in Fig. 11 in a section plane designated XIV in Fig. 13.

[0054] Fig. 15 shows a sectional view through the brake pad shown in Fig. 11 in a section plane designated XV in Fig. 13.

[0055] Fig. 16 shows a sectional view through the brake pad shown in Fig. 11 in a section plane designated XVI in Fig. 13.

[0056] Fig. 17 shows a sectional view through the brake pad shown in Fig. 11 in a section plane designated XVII in Fig. 13, and

[0057] Fig. 18 shows a schematic isometric view of a variant of the turnbuckle.

[0058] In the following figure descriptions, terms such as top, bottom, left, right, front, rear, etc., refer exclusively to the exemplary representation and position of the brake linings, drum brake, brake drum, pressure piece, retaining elements, and the like as chosen in the respective figures. These terms are not to be understood as restrictive; that is, these references may change due to different working positions, mirror-symmetrical design, or similar factors.

[0059] In Figure 1, reference numeral 1 denotes an embodiment of a drum brake according to the invention, in particular for use on a commercial vehicle.

[0060] The drum brake 1 has a brake drum 2 rotatably mounted about a rotational axis AR, which is connected in a rotationally fixed manner to a hub of a wheel axle (not shown here) via an anchor housing 5.

[0061] In a receiving space within the brake drum 2, as shown in Figure 2, several brake linings 3 are arranged according to a first embodiment, each with a lining carrier 32 and a friction lining 31 arranged thereon. The brake linings 3 are arranged with their friction linings 31 facing an inner surface of the brake drum 2.

[0062] As further shown in Figure 2, a clamping device 4 with a wedge ring 41 which is displaceable on a cylindrical sleeve 51 of the anchor housing 5 parallel to the axis of rotation AR of the brake drum 2 is arranged on the anchor housing 5, with which the brake linings 3 can be pressed against the inner surface of the brake drum 2, which is designed as a friction surface, radially to the axis of rotation AR of the brake drum 2 (direction r shown in Figure 1).

[0063] To transmit the movement of the wedge ring 41 to the brake linings 3, a respective pressure wedge 33 is arranged on a side of the lining carrier 32 facing away from the friction lining 31 as part of a respective brake lining 3.

[0064] A pressure piece 7 is arranged between the pressure wedge 33 and the pad carrier 32. The pressure piece 7, as well as the embodiments of pressure pieces 170, 270 shown in Figures 6 and 11, is held in the radial direction on the pad carrier 32, 132, 232 by means of at least one retaining element in a form-fit and / or friction-fit manner.

[0065] The pressure wedge 33 rests on a pressure surface of the wedge ring 41.

[0066] The wedge ring 41 is preferably displaceable via a service brake piston 62 of a brake cylinder arrangement 6 parallel to the axis of rotation AR of the brake drum 2 from a non-braking position to a braking position in a direction z, as shown in Figure 3.

[0067] Between the wedge ring 41 and the pressure wedge 33 of the brake pad 3, a slide 42 with several rolling elements 43 is arranged to reduce friction between the pressure surface of the wedge ring 41 and the pressure wedge 33 of the brake pad 3.

[0068] The brake cylinder assembly 6, as part of the clamping device 4, serves to carry out the radial pressing movement of the brake shoes 3 against the inner surface of the brake drum 2.

[0069] The brake cylinder assembly 6 has a housing 61 that is fixedly attached to the armature housing 5 in the receiving space of the brake drum 2. The service brake piston 62 is arranged to be displaceable relative to this housing 61 parallel to the axis of rotation AR of the brake drum 2.

[0070] Furthermore, the brake cylinder arrangement 6 has a parking brake piston 63 which is displaceable relative to the housing 61 parallel to the axis of rotation AR of the brake drum 2 and can be acted upon by the spring force of a spring element 66 preferably designed as a disc spring via an intermediate plate 65.

[0071] The brake cylinder assembly 6 also has several plungers 64 which serve to transmit a movement of the parking brake piston 63 to the service brake piston 62.

[0072] Furthermore, compressed air inlets are provided, which lead firstly into a service brake pressure chamber between the housing 61 and the service brake piston 62 and secondly into a parking brake pressure chamber 67 between the housing 61 and the parking brake piston 63.

[0073] The movement of the service brake piston 62 is always important for the actuation of the brake shoes 3; this movement is effected by supplying compressed air to the service brake pressure chamber in the event of an intended reduction in the speed of the commercial vehicle, a so-called service braking process.

[0074] In the event of the intended locking of the brake, which serves to prevent the commercial vehicle from unintentionally rolling away in a parked situation, compressed air present in the parking brake pressure chamber 67 during ferry operation is released from the parking brake pressure chamber 67, resulting in a displacement of the parking brake piston 63 towards the service brake piston 62. This displacement is caused by the force exerted by the spring element 66 on the rear side of the parking brake piston 63 facing away from the service brake piston 62.

[0075] The connection of the pressure piece 7 to the coating carrier 32 shown in Figure 2 is shown in Figure 3 as a close-up.

[0076] Alternative embodiments of a connection between a pressure piece 7, 170, 270 and a lining holder 32, 132, 232 are shown in Figures 6 and 11, respectively. In the first embodiment shown in Figures 3 to 5, a pin 34 projects radially from a side of the lining carrier 32 facing away from the friction lining 31.

[0077] The pressure piece 7 has a recess 71 on an end face facing the support carrier 32, which receives the pin 34.

[0078] The retaining element is designed here as a slotted bushing 8, 8' encompassing the pin 34 (Figures 3 and 4) or as a snap ring 8" encompassing the pin 34 (Figure 5).

[0079] As further shown in Figure 3, the slotted bushing 8 is provided here with a rim that engages in a groove 35 on the pin 34.

[0080] Alternatives to such a groove 35 are shown in Figures 4 and 5.

[0081] In the embodiment shown in Figure 4, the bushing is almost completely enclosed in a corresponding groove in a cylindrical surface of the pin 34.

[0082] In the embodiment shown in Figure 5, in which a retaining element designed as a snap ring 8" is provided, this is inserted into a correspondingly smaller groove in the outer surface of the pin 34.

[0083] In all of these embodiments, the bushing 8, 8' or the snap ring 8" serves to form an interference fit between the pin 34 and the recess 71 of the pressure piece 7, which meets the requirements of the environmental conditions.

[0084] There is preferably a constructive clearance between the pin 34 and the inner diameter of the bushings 8, 8' or the snap ring 8" which allows the brake pad 3 one degree of freedom in the circumferential direction U to come into contact with the support surface of the housing 5.

[0085] In a second embodiment shown in Figures 6 to 10, in which the pressure piece 170 has a pressure piece neck 171 extending in the radial direction and a pressure piece head 172, the end face of which rests on the lining carrier 132 and a pressure piece receptacle 135 is formed in a rear side of the lining carrier 132 facing away from the friction lining 131, at least one retaining element designed as a retaining bolt 180 is held on the lining carrier 132 in such a way that it presses the pressure piece head 172 against the lining carrier 132, as can be clearly seen in Figure 10.

[0086] The pressure piece receptacle 135 is designed in particular in the form of a recess adapted to the circumference of the pressure piece head 172.

[0087] In the embodiment shown in Figures 6 to 10, two such retaining bolts 180 are provided.

[0088] At least one of these retaining bolts 180 has a flattened section 181.

[0089] The pressure piece head 172 is preferably conically shaped here.

[0090] In the assembled state, the retaining bolts 180 are preferably located close to the circumferential edge of the pressure piece head 172 and are received in bolt receptacles 134 provided for this purpose in the lining carrier 132.

[0091] The retaining bolts 180 preferably extend in the circumferential direction and are rotatably held in the support carrier 132 about their longitudinal axis.

[0092] To mount the pressure piece 170 on the support carrier 132, the retaining bolt 180, which extends with the flattening 181, is rotated so that the flattening 181 maximizes a gap for inserting the pressure piece 170, here the pressure piece head 172.

[0093] After the pressure piece 170 is inserted into the pressure piece receptacle 135 of the lining carrier 132, the retaining bolt 180, which has a flattened surface 181, is rotated so that the cylindrical surface of the retaining bolt 180 rests against the conical outer surface of the pressure piece head 172 and thereby presses the pressure piece head 172 against the rear side of the lining carrier 132 facing away from the friction lining.

[0094] As further shown in Figures 6 to 10, the retaining bolt 180 can be fixed in its clamping position pressing the pressure piece head 172 against the lining carrier 132.

[0095] In the illustrated embodiment, a threaded pin 190 is provided which can be screwed into a threaded bore 133 of the pad carrier 132, the end face of which presses against the flattened surface 181 of the retaining bolt 180 in the assembled state and thus fixes the retaining bolt 180 in this position.

[0096] Another preferred embodiment of a brake pad 230 according to the invention is described below with reference to Figures 11 to 18.

[0097] In this embodiment, the pressure piece 270 is designed similarly to the variant described with reference to Figures 6 to 10, with a pressure piece neck 271 extending in a radial direction and a pressure piece head 272 adjoining it, the end face of which rests against the lining carrier 232.

[0098] In contrast to the previous embodiment, in this embodiment a pin 234 projects radially from a side of the lining carrier 232 facing away from the friction lining 231. The pressure piece 270 has a recess 277 on an end face facing the lining carrier 232, which serves to receive the pin 234.

[0099] In this embodiment, the retaining element is designed as a turnbuckle 280 which encompasses the pin 234 and can be fixed in the recess 277 of the pressure piece 270, enabling the formation of a bayonet-like connection between the pressure piece 270 and the lining carrier 232.

[0100] The turnbuckle 280 can be fixed in an undercut 275 of the pressure piece head 272 in the direction of a longitudinal extension of the pin 234, as shown in Figures 14 and 15. Figures 14 and 15 show sections made at different heights perpendicular to the radial through the brake lining 230.

[0101] Furthermore, a projection 236 is also provided on the pin 234, which can be engaged by the turnbuckle 280.

[0102] For this purpose, as shown in Figure 18, a guide edge 285 is provided in the turnbuckle 280 which is inclined at an acute angle to the longitudinal axis of the pin 234, along which the pin 234 slides when inserted into the turnbuckle 280 until it reaches an undercut 287 in an inner wall of the turnbuckle 280.

[0103] For easy assembly and reliable fixing of the support carrier 232 to the pressure piece 270, a pressure surface 284 is also provided on the turnbuckle 280, against which a clamping element 290, here in the form of a compression spring, is located in the pressure piece head 272.

[0104] The clamping element 290 exerts a torque L in the assembled state of the pin 234, which holds the turnbuckle 280 in the undercut 275 of the pressure piece 270 and in engagement with the projection 236 of the pin 234, as shown by way of example in Figure 15.

[0105] When mounting the turnbuckle 280 into the pressure piece head 272, the clamping element 290 is first pre-tensioned in order to be able to insert the turnbuckle 280 into the pressure piece 270.

[0106] When the clamping element 290 is subsequently released, the turnbuckle 280 is rotated into the undercut 275 of the pressure piece 270 and is thus axially secured to the axis of rotation of the pressure piece 270, which in the installed state of the brake lining 230 in the drum brake corresponds to the radial to the axis of rotation AR of the brake drum.

[0107] If the lining carrier 232 with the friction lining 231 arranged on it is now pressed into the pressure piece 270 with the pin 234 formed on the lining carrier 232, the projection 236 of the pin 234 slides along the guide edge 285 of the turnbuckle 280.

[0108] The turnbuckle 280 is pressed against the clamping element 290, which here is designed as a compression spring, and rotated in the process. If the projection 236 of the pin 234 now overcomes a front end of the guide edge 285, the clamping element 290 pushes the turnbuckle 280 back, so that the projection 236 of the pin 234 slides into the undercut 287 of the turnbuckle 280.

[0109] This undercut 287 of the turnbuckle 280 is preferably designed as a locking edge inclined at an obtuse angle to the longitudinal axis of the pin 234.

[0110] In operation of the drum brake, the brake lining 230 is located in a brake lining shaft of the housing 5, so that the brake lining 230 is rotationally secured in operation, so that the pin 234 cannot be pushed out of the turnbuckle 280 by its own force.

[0111] To remove the brake pad 230, a significantly higher force must be overcome compared to the assembly, in order to pull the projection 236 of the pin 234 over the undercut 287 which is inclined at an obtuse angle to the axis of rotation AR of the pressure piece 270.

[0112] A further advantage of designing this undercut 287, which is designed as a locking edge, as being inclined at an obtuse angle to the longitudinal axis of the pin 234, is that axial play between the lining carrier 232 and the pressure piece 270 is completely eliminated, since the clamping element 290 rotates the band lock 280 into the projection 236 of the pin 234 via the lever arm L (shown in Figure 15).

[0113] Reference symbol list

[0114] 1 drum brake

[0115] 2 brake drums

[0116] 3 brake pads

[0117] 31 friction lining

[0118] 32 deck supports

[0119] 33 Pressure wedge

[0120] 34 cones

[0121] 35 Nut

[0122] 4 Clamping device

[0123] 41 Wedge ring

[0124] 42 sleds

[0125] 43 rolling elements

[0126] 5 anchor housings

[0127] 51 pressure surface

[0128] 6 brake cylinder arrangement

[0129] 61 Brake cylinder housing

[0130] 62 service brake pistons

[0131] 63 Parking brake pistons

[0132] 64 pestles

[0133] 65 Intermediate plate

[0134] 66 Spring element

[0135] 67 Parking brake pressure chamber

[0136] 68 Seal

[0137] 69 Seal

[0138] 7 Printing piece

[0139] 71 Exclusion

[0140] 72 Inner perimeter wall

[0141] 8, 8' Bushing 8" Snap Ring

[0142] 130 brake pads

[0143] 131 Friction lining

[0144] 132 decking carriers

[0145] 133 Threaded hole

[0146] 134 bolt holder

[0147] 135 Pressure piece holder

[0148] 170 printed piece

[0149] 171 Pressure piece neck

[0150] 172 Pressure piece head

[0151] 173 Internal threads

[0152] 180 retaining bolts

[0153] 181 Flattening

[0154] 190 threaded pin

[0155] 191 Mother

[0156] 230 brake pad

[0157] 231 Friction lining

[0158] 232 decking carriers

[0159] 234 cones

[0160] 235 Pressure piece holder

[0161] 236 lead

[0162] 270 printing piece

[0163] 271 Pressure piece neck

[0164] 272 Pressure piece head

[0165] 273 Internal thread

[0166] 274 Clamping element holder

[0167] 275 undercut

[0168] 276 hits

[0169] 277 Exclusion

[0170] 280 Turnbuckle 281 Stop

[0171] 282 stops

[0172] 283 Counter surface

[0173] 284 Printing area 285 Guiding edge

[0174] 286 counter surface

[0175] 287 Undercut

[0176] 290 clamping element

[0177] AR Rotation Axis

[0178] U Circumferential direction of the brake drum r Direction z Direction

Claims

Claims 1. Brake lining (3, 130, 230) for a radially actuated drum brake (1 ) of a commercial vehicle, comprising - a coating carrier (32, 132, 232), - at least one friction lining (31 , 131 , 231 ) arranged on the lining carrier (32, 132, 232) with a friction surface shaped in a circular arc segment shape in a circumferential direction, - a pressure piece (7, 170, 270) attached to the pad carrier (32, 132, 232), characterized in that - the pressure piece (7, 170, 270) is held in a radial direction by means of at least one retaining element in a form-fit and / or friction-fit manner.

2. Brake pad (3, 130, 230) according to claim 1 , characterized in that the pressure piece (7, 170, 270) is held without play in the radial direction and with play in the circumferential direction.

3. Brake pad (3) according to claim 1 or 2, characterized in that a pin (34) projects radially from a side of the pad carrier (32) facing away from the friction lining (31) and the pressure piece (7) has a recess (71) on an end face facing the pad carrier (32) for receiving the pin (34), wherein the retaining element is designed as a slotted bushing (8, 8') encompassing the pin (34) or as a snap ring (8") encompassing the pin (34).

4. Brake pad (3) according to claim 3, characterized in that a groove (35) is formed on an outer circumference of the pin (34) and / or an inner circumferential wall (72) of a recess (71) of the pressure piece (7) receiving the pin (34), in which the bushing (8, 8') or the snap ring (8") is partially inserted.

5. Brake pad (3) according to claim 3 or 4, characterized in that the bushing (8, 8') or the snap ring (8") is provided to form an interference fit between the pin (34) and the recess (71) of the pressure piece (7).

6. Brake pad (130) according to claim 1 or 2, characterized in that the pressure piece (170, 270) has a radially extending has an extending pressure piece neck (171 , 271 ) and a pressure piece head (172, 272) whose end face rests against the lining carrier (132, 232).

7. Brake pad (130) according to claim 6, characterized in that a pressure piece receptacle (135, 235) is formed in a rear side of the pad carrier (132, 232) facing away from the friction lining (131, 231), in particular in the form of a recess adapted to a circumference of the pressure piece head (172, 272).

8. Brake pad (130) according to claim 6 or 7, characterized in that at least one retaining element designed as a retaining bolt (180) is held on the pad carrier (132) in such a way that it presses the pressure piece head (172) against the pad carrier (132).

9. Brake pad (130) according to claim 8, characterized in that at least one of the retaining bolts (180) has a flattening (181 ).

10. Brake pad (130) according to claim 9, characterized in that the retaining bolt (180) can be fixed in its clamping position pressing the pressure piece head (172) against the pad carrier (132).

11. Brake pad (130) according to claim 10, characterized in that the retaining bolt (180) can be fixed in its clamping position pressing the pressure piece head (172) against the pad carrier (132) by a threaded pin (190) which can be screwed into a threaded bore (133) of the pad carrier (132).

12. Brake pad (230) according to one of claims 1, 2, 6 or 7, characterized in that a pin (234) projects radially from a side of the pad carrier (232) facing away from the friction lining (231) and the pressure piece (270) has a recess (277) on an end face facing the pad carrier (232) for receiving the pin (234), wherein the retaining element is designed as a turnbuckle (280) encompassing the pin (234) and fixable in the recess (277) of the pressure piece (270) to form a bayonet-like connection.

13. Brake pad (230) according to claim 12, characterized in that the turnbuckle (280) can be fixed in an undercut (275) of the pressure piece head (272) in the direction of the longitudinal extension of the pin (234).

14. Brake pad (230) according to claim 12 or 13, characterized in that a projection (236) is provided on the pin (234) which can be engaged by the turnbuckle (280).

15. Brake pad (230) according to one of claims 12 to 14, characterized in that the turnbuckle (280) has a guide edge (285) inclined at an acute angle to the longitudinal axis of the pin (234) for introducing the pin (234) into an undercut (287) in an inner wall of the turnbuckle (280).

16. Brake pad (230) according to claim 15, characterized in that the undercut (287) is designed as a locking edge inclined at an obtuse angle to the longitudinal axis of the pin (234).

17. Brake pad (230) according to one of claims 12 to 16, characterized in that the turnbuckle (280) has a pressure surface (284) against which a clamping element (290) mounted in the pressure piece head (272), preferably a compression spring, bears, wherein the clamping element (290) exerts a torque (L) in the mounted state of the pin (234) which holds the turnbuckle (280) in the undercut (275) of the pressure piece (270) and in engagement with the projection (236) of the pin (234).

18. Radially actuated drum brake (1 ) for a commercial vehicle, comprising - a brake drum (2) rotatably mounted about an axis of rotation (AR), - at least two brake linings (3, 130, 230) mounted in a receiving space of the brake drum (2), - an armature housing (5) with a clamping device (4) arranged thereon in a rotationally fixed manner and with a wedge ring (41) which is displaceable on a cylindrical sleeve (51) of the armature housing (5) parallel to the axis of rotation (AR) of the brake drum (2), with which the brake linings (3, 130, 230) can be pressed against an inner surface of the brake drum (2) radially to the axis of rotation (AR) of the brake drum (2), characterized in that - the brake pads (3, 130, 230) are designed according to any one of the preceding claims 1 to 17.

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