Disc brakes for a commercial vehicle

Abstract

A disc brake, comprising a brake caliper (1) in which two brake pads (2) are arranged which can be pressed against a brake disc in operation, one of which, on the action side, can be actuated by means of a clamping device (3) via at least one axially adjustable adjusting spindle (4) carrying a pressure piece (5), and the adjusting spindle (4) is guided through an opening in a cover (7) that closes a receiving chamber of the brake caliper (1), forming an annular gap, wherein a sealing arrangement (12) is provided in the area of ​​the opening to seal the receiving chamber, which bears against the pressure piece (5) on one side and is held on the other side on the inside of an axially oriented collar (8) that circumferentially delimits the opening, wherein the sealing arrangement (12) has a bellows (10) and a concentrically arranged secondary seal (11), and the secondary seal (11) and the bellows (10) are formed in one piece, is designed such thatthat the secondary seal (11), which has a central opening and is more dimensionally stable than the bellows, has a circumferential shell which is attached to the inside of the collar (8) by friction or material interlock, wherein the bottom of the secondary seal (11), which is angled towards the shell, bears against the adjusting spindle (4) with its edge, which is formed as a bead (15) and defines the central opening, and the bellows (10) is connected to the pressure piece (5) by form-fitting, material interlock, or friction interlock with its end, which is formed as a thickening and is radially opposite to the shell.

Description

[0001] The invention relates to a disc brake for a commercial vehicle according to the preamble of claim 1.

[0002] To prevent moisture and dirt from penetrating the receiving chamber of a disc brake caliper during driving, which can lead to corrosion of functionally relevant components located in the receiving chamber, including in particular a clamping device, the receiving chamber on the side which, in the case of a sliding caliper disc brake, is associated with the clamping-side brake pad, is largely closed by a sealing cover.

[0003] To actuate the brake, at least one adjusting spindle is provided which is rotatably mounted in a bridge, on which a pneumatically or electromechanically actuated brake lever engages in such a way that a pressure piece arranged on the adjusting spindle is pressed against the associated brake pad.

[0004] The adjusting spindle carrying the pressure piece is guided through an opening in the cover, which is limited by a collar axially aligned towards the brake lining. The diameter of the opening is larger than the outer diameter of the adjusting spindle, resulting in a circumferential annular gap.

[0005] A bellows is provided to close the annular gap, which rests on the adjusting spindle or pressure piece on one side and is held in the area of ​​the opening, especially on the inner surface of the collar, on the other.

[0006] A secondary seal, which covers the bellows on the side facing the receiving chamber, forms a redundant sealing element that protects the receiving chamber from coarse dirt in the event of a possible failure of the bellows.

[0007] During braking, the adjusting spindle is moved towards the brake disc. As the brake pads wear, the adjusting spindle is extended further to ensure a constant clearance. This movement is compensated for by the bellows to guarantee the airtightness of the receiving chamber.

[0008] The bellows seals at two points: firstly, at the transition to the pressure piece, and secondly, at the transition to the closure cap. The bellows is attached to the pressure piece by crimped grooves, while it is attached to the collar of the closure cap by friction.

[0009] However, this requires adherence to very tight tolerances as well as a corresponding quality of the lid surface.

[0010] It is known from the prior art to design the secondary seal and the bellows as separate parts, with the secondary seal covering the bellows on the side facing the brake pad. The secondary seal is pressed onto a collar of a bridge that receives the adjusting spindle to prevent radial rotation. However, this type of seal is disadvantageous in terms of both manufacturing and assembly, and is particularly costly.

[0011] DE 10 2018 101 288 A1 therefore proposes forming the secondary seal and the bellows as a single piece; however, this assembly is designed in such a way that it can only be realized with considerable manufacturing effort. Furthermore, the secondary seal rests with its inner surface against the outer surface of the collar of the closure cover, with the molded bellows adjoining this surface and being held in place by the pressure piece.

[0012] In order to achieve sufficient sealing of the annular gap, the secondary seal has a sealing bead that fills this annular gap, with this sealing bead being arranged in the edge area of ​​the central opening of the secondary seal, which in turn rests against the adjusting spindle.

[0013] A comparable sealing arrangement, in which the secondary seal and the bellows are made of an elastic material, is disclosed in WO 2019 / 137 768 A1. However, this makes the assembly of the sealing arrangement considerably more difficult.

[0014] The invention is based on the objective of further developing a disc brake of the generic type in such a way that it is easier and more cost-effective to manufacture and assemble.

[0015] This problem is solved by a disc brake having the features of claim 1.

[0016] The secondary seal, which is pot-shaped, has a central opening, and is more dimensionally stable than the bellows, and has a circumferential mantle that is attached to the inside of the collar that limits the opening of the closure lid by friction or material interlock.

[0017] The base, angled towards the casing and extending radially towards the adjusting spindle, rests against the adjusting spindle with its bead-shaped edge that defines the central opening. The bellows, which, as is known from the prior art, is made of plastic in one piece with the secondary seal, is connected to the pressure piece by a form-fit, material-fit, or friction-fit connection at its end, which is formed as a thickening and is radially opposite the casing of the secondary seal.

[0018] This design offers a number of advantages. For example, it is worth noting that the sealing assembly, as a single-piece unit, is extremely easy to manufacture, which in turn minimizes costs.

[0019] Likewise, the assembly of the sealing arrangement is also significantly simplified, whereby, as mentioned, the secondary seal is more dimensionally stable than the bellows and forms a receiving space for the bellows.

[0020] The sealing assembly is attached at only two points: firstly, the bellows to the pressure piece, and secondly, the secondary seal to the collar of the end cap, which extends either axially outwards, i.e., away from the caliper's receiving chamber, or axially inwards towards the receiving chamber. The respective contact areas of the secondary seal and the bellows are reinforced, preferably with a metal or plastic ring, the latter made of a relatively hard plastic.

[0021] Various configurations of the bellows' end section are conceivable for attaching it to the pressure piece. The connection to the pressure piece can be form-fit, material-fit, or friction-fit, with material-fit achieved through bonding. This ensures both axial and radial securing of the bellows, as well as the secondary seal.

[0022] This is held against rotation at the collar, but allows radial and axial movement of the adjusting spindle, with the bead-shaped edge limiting the central opening lying close to the adjusting spindle.

[0023] As mentioned, the secondary seal is more dimensionally stable than the bellows, and the production of this sealing arrangement using the known 2-component injection molding process is a suitable option.

[0024] Further advantageous embodiments of the invention are characterized in the dependent claims.

[0025] Exemplary embodiments of the invention are described below with reference to the accompanying drawings.

[0026] They show: Fig. 1. A disc brake according to the state of the art in a sectional top view Fig. Figures 2-7 each show an embodiment of the invention as part of the disc brake according to the invention in an enlarged section.

[0027] In the Fig. Figure 1 shows a schematic representation of a disc brake according to the prior art, with a brake caliper 1 designed as a sliding caliper that covers a brake disc (not shown), in which two brake pads (also not shown) are arranged in a brake carrier 2, which can be pressed against the brake disc when in operation, i.e., when braking.

[0028] First, the clamping-side brake pad is pressed against the brake disc by means of a clamping device 3, while subsequently, due to the reaction forces, the reaction-side brake pad is pressed against the brake disc by taking along the changing brake caliper 1.

[0029] In the example, the clamping device 3 has two axially adjustable adjusting spindles 4 arranged parallel and spaced apart from each other, which are guided through an opening 9 of a closing cover 7 which closes a receiving chamber of the brake caliper 1, forming an annular gap.

[0030] A sealing arrangement 12 is provided to seal the receiving space in the area of ​​the respective opening 7, which consists of a bellows 10 and a secondary seal 11, each of which is designed and attached separately from each other.

[0031] The secondary seal 11 is held on one side by the sealing cap 7 and rests against the adjusting spindle 4 on the other. The bellows 10 is also held on one side by the sealing cap 7, while on the other side it rests against a pressure piece 5, which is attached to the end of the adjusting spindle 4 facing the brake lining.

[0032] The adjusting spindle 4 is connected to an adjusting device 6, by means of which it is possible to compensate for a wear-related clearance.

[0033] The formed annular gap is closed on its outer side facing away from the receiving space by the bellows 10, which circumferentially limits the opening 7 and is held sealingly on a collar that extends axially in the direction of the clamping-side brake pad and is formed on the closure cover 7.

[0034] The secondary seal 11 protects the receiving chamber from ingress of dirt if the bellows 10 is damaged and its protective function is no longer guaranteed.

[0035] In the Fig. In 2-7, the sealing arrangement 12 according to the invention can be seen in an enlarged section on one side, which, as mentioned, consists of the bellows 10 and the secondary seal 11, the latter being of a cup-like design.

[0036] With its edge region facing away from the adjusting spindle 4, the secondary seal 11 is frictionally or materially attached to the inside of the collar 8, in any case preventing rotation relative to the collar 8. For this purpose, a dimensionally stable, preferably metal, and in this example Z-shaped reinforcing ring 13 is embedded in the edge region. The applied contact pressure holds the secondary seal 11 frictionally against the collar 8. The bellows 10 connects to the secondary seal 11 in this area.

[0037] An edge angled towards the axially extending outer surface of the secondary seal 11, and defining a central opening of the secondary seal 11, is formed as a bead 15, which lies close to the adjusting spindle 4 in such a way that free rotation and axial movement are possible.

[0038] According to the invention, the bellows 10 is connected to the pressure piece 5 by means of a form-fit, form-fit, material-fit or friction-fit connection at its end which is radially opposite to the shell of the secondary seal 11.

[0039] In the Fig. In the embodiment shown in 2, this end is reinforced by an embedded support ring 14 with a J-shaped cross-section, which allows for a frictional connection with the pressure piece 5, but is also suitable for producing an adhesive connection.

[0040] During the Fig. In the embodiment shown in Figure 3, the end of the bellows 10 that rests against the pressure piece 5 is designed as an O-ring 16, which rests against the pressure piece 5 and is secured in the axial direction by a support ring 17 opposite the pressure piece 5, which is connected to the pressure piece 5 by friction or material bonding, with the O-ring 16 resting against the support ring 17.

[0041] The Fig. Figure 4 shows a variant of the attachment of the bellows 10 to the pressure piece 5, in which a collar 18 is formed on the adjusting spindle 4 for axial support of the O-ring 16, which also serves as a bearing for the O-ring 16, thus providing axial securing of the O-ring 16.

[0042] In the Fig. In the example shown in Figure 5, the bellows 10 is connected to the pressure piece 5 by an embedded spring or wire ring 19 to create a frictional connection, while the Fig. 6 the connection area of ​​the bellows 10 with the pressure piece 5 represents an end formed in cross-section as a polygon 20, here cuboid, which is glued to the pressure piece 5.

[0043] Finally, in the Fig.Figure 7 shows another variant in which the connection of the bellows 10 is made by a tongue and groove connection, wherein the pressure piece 5 has a circumferential groove 22 in which the bead-like thickening 21 of the bellows 10 is inserted, thus also ensuring axial securing of the bellows 10. Reference symbol list 1 brake caliper 2 brake carriers 3 Clamping device 4 adjusting spindles 5 printing pieces 6 Adjustment device 7 sealing caps 8 collars 9 Opening 10 bellows 11 Secondary seal 12 Sealing arrangement 13 Reinforcing ring 14 Support ring 15 bulge 16 O-ring 17 Support ring 18 cuffs 19 Spring or wire ring 20 polygon 21 lumpy thickening 22 Nut QUOTES INCLUDED IN THE DESCRIPTION

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

[0000] DE 10 2018 101 288 A1

[0011] WO 2019 / 137

[0013]

Claims

[1] Disc brake, comprising a brake caliper (1) in which two brake pads (2) which can be pressed against a brake disc in operation are arranged, one of which, on the action side, can be actuated by means of a clamping device (3) via at least one axially adjustable adjusting spindle (4) carrying a pressure piece (5), and the adjusting spindle (4) is guided through an opening in a cover (7) which closes a receiving chamber of the brake caliper (1), forming an annular gap, wherein a sealing arrangement (12) is provided for sealing the receiving chamber in the area of ​​the opening, which bears on one side against the pressure piece (5) and on the other side is held on the inside of an axially oriented collar (8) which circumferentially delimits the opening, wherein the sealing arrangement (12) has a bellows (10) and a concentrically arranged secondary seal (11), and the secondary seal (11) and the bellows (10) are formed in one piece, characterized by, that the secondary seal (11), which has a central opening and is more dimensionally stable than the bellows, has a circumferential shell which is attached to the inside of the collar (8) by friction or material interlock, wherein the bottom of the secondary seal (11), which is angled to the shell, rests against the adjusting spindle (4) with its edge, which is formed as a bead (15) and defines the central opening, and the bellows (10) is connected to the pressure piece (5) by form interlock, material interlock or friction interlock with its end, which is formed as a thickening and is radially opposite to the shell. [2] Disc brake according to claim 1, characterized by , that the secondary seal (11) is cup-shaped. [3] Disc brake according to claim 1 or 2, characterized by, that the thickening of the bellows (10) which rests against the pressure piece (5) has a support ring (14) with which the thickening can be pressed against the pressure piece (5), and / or the end area of ​​the secondary seal (11) which rests frictionally against the collar (8) has a dimensionally stable reinforcing ring (13). [4] Disc brake according to claim 1 or 2, characterized by , that the thickening of the bellows (10) adjacent to the pressure piece (5) is designed as an O-ring (16). [5] Disc brake according to one of the preceding claims, characterized by , that a support ring (17) is attached to the pressure piece (5), against which the thickening rests for axial securing of the bellows (10). [6] Disc brake according to one of the preceding claims, characterized by , that the adjusting spindle (4) has a circumferential collar (18) at its end area facing the pressure piece (5), against which the thickening rests. [7] Disc brake according to one of the preceding claims, characterized by , that a spring or wire ring is embedded in the adjacent end area for the friction-fit retention of the bellows (10) on the pressure piece (5). [8] Disc brake according to one of the preceding claims, characterized by , that the thickening of the bellows (10) adjacent to the pressure piece (5) is formed in cross-section as a polygon (20) which is bonded to the pressure piece (5). [9] Disc brake according to one of the preceding claims, characterized by , that the bellows (10) is connected to the pressure piece (5) by a tongue and groove connection. [10] Disc brake according to one of the preceding claims, characterized by , that the pressure piece (5) has a circumferential groove (22) into which a bead-like thickening (21) of the bellows (10) is inserted. [11] Disc brake according to one of the preceding claims, characterized by, that the sealing arrangement (12) is manufactured using the 2-component injection molding process.

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