Brake piston of a disc brake, application device and disc brake

Abstract

Brake piston (20) of a disc brake of a commercial vehicle, comprising - an adjusting spindle (30) and - a pressure piece (40), - wherein the adjusting spindle (30) has a threaded tube (31) with an external thread (32) and a spindle base (35) with a central pin receptacle (34) and an annular end face (33) surrounding the pin receptacle (34), - wherein the pressure piece (40) has a pressure surface (41) facing an action-side brake pad (4) and a central pin (42) projecting into the pin receptacle (34) of the spindle base (35), characterized in that - a support web (43) concentrically surrounding the pin (42) is formed on the pressure piece (40), wherein the annular end face (33) of the spindle base (35) surrounding the pin receptacle (34) rests on a base (44) of the pressure piece (40) between the pin (42) and the support web (43), - where the diameter (d F) of the spindle base (35) is at least 60% of the outer diameter (d) of the pressure surface (41) of the pressure piece (40).

Description

[0001] The present invention relates to a brake piston of a disc brake of a commercial vehicle according to the preamble of claim 1 as well as an application device according to the preamble of claim 6 and a disc brake.

[0002] A generic disc brake with an application device is known, for example, from DE 10 2015 110 231 B4.

[0003] During braking, the force in a disc brake is typically transferred to the brake pad via a threaded tube and a pressure piece attached to the end of the threaded tube. The thread of this threaded tube is typically screwed into a bridge of the disc brake. By unscrewing the threaded tube from the bridge, wear on the brake pads and brake disc is compensated. The pressure piece is typically mounted on the threaded tube in such a way that it does not rotate with the threaded tube.

[0004] The coupling of the pressure piece to the adjusting spindle is usually done via a pin that projects into a corresponding receptacle. The pin can be formed on the spindle base, as shown in Fig. 1 of DE 10 2015 110 231 B4. Alternatively, the pin can also be formed on the pressure piece, as shown in Fig. 2 of the same publication.

[0005] In order to avoid diagonal wear, especially in disc brakes that have only a single brake piston, it is known, for example from DE 10 2019 109 817 A1, that the pressure surface of the pressure piece or the abutment surface on the brake pad is modified in such a way that they are offset on the outlet side, which has proven successful in practice.

[0006] However, this requires machining of both the pressure surface of the pressure stamp and the corresponding pressure surface of the action-side brake pad.

[0007] From DE 10 2019 126 584 A1 it is known to provide an edge on an annular edge of the pressure piece, which edge engages over a threadless area of ​​a threaded tube of the adjusting spindle for axially securing the pressure piece to the adjusting spindle.

[0008] The object of the present invention is to provide a brake piston, an application device and a disc brake with which diagonal wear can be reliably avoided or at least largely reduced in an even simpler manner.

[0009] This object is achieved by a brake piston having the features of claim 1, by an application device having the features of claim 6 and by a disc brake having the features of claim 9.

[0010] The brake piston according to the invention of a disc brake of a commercial vehicle has an adjusting spindle and a pressure piece, wherein the adjusting spindle has a threaded tube with an external thread and a spindle base with a central pin receptacle and an annular end face surrounding the pin receptacle.

[0011] The pressure piece has a pressure surface facing an action-side brake pad and a central pin protruding into the pin receptacle of the spindle base.

[0012] A support web is formed on the pressure piece which concentrically surrounds the pin, whereby the annular end face of the spindle base which surrounds the pin receptacle rests on a base of the pressure piece between the pin and the support web.

[0013] The diameter of the spindle base is at least 60% of the outer diameter of the pressure surface of the pressure piece.

[0014] With such a brake piston, a further improvement in the support of the pressure piece compared to the adjusting spindle is achieved.

[0015] The risk of tilting of the pressure piece relative to the adjusting spindle, which can lead to diagonal wear of the brake pads, is further reduced with the brake piston according to the invention in particular by the fact that the pressure surface between the pressure piece and the adjusting spindle is shifted further in the direction of the pressure surface of the pressure piece interacting with the brake pad.

[0016] The ratio of the diameter of the spindle base relative to the outer pressure surface of the pressure piece ensures a further reduced risk of the pressure piece tipping relative to the adjusting spindle.

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

[0018] According to a further advantageous embodiment of the brake piston according to the invention, the radial width of the ring of the adjusting spindle forming the annular end face is at least 40% of a diameter of the spindle base spanned by the annular end face (33).

[0019] This creates a large effective surface between the pressure piece and the adjusting spindle.

[0020] According to a further advantageous embodiment, a height of the pin viewed in the direction of the longitudinal axis of the adjusting spindle, viewed from the bottom of the pressure piece, is at least 60% of the total height of the pressure piece.

[0021] This ratio achieves, on the one hand, improved guidance of the pressure piece in the threaded tube and, on the other hand, a pressure point shift of the pressure point between the adjusting spindle and the pressure piece in the direction of the pressure surface of the pressure piece.

[0022] According to a further preferred embodiment, the diameter of the spindle base is larger than a diameter of the threaded tube of the adjusting spindle.

[0023] This feature also improves the support of the pressure piece on the threaded pipe due to the wider support provided by the spindle base with a larger diameter relative to the pressure piece compared to the state of the art.

[0024] To decouple the pressure piece from the rotary movement of the adjusting spindle, a sliding sleeve is arranged between an inner surface of the spindle base journal holder and an outer surface of the journal.

[0025] The application device arranged according to the invention in a brake calliper of a disc brake for a commercial vehicle has a brake lever, a bridge on which the brake lever is supported and at least one brake piston.

[0026] At the end of the bridge facing away from the brake lever, at least one adjusting spindle of at least one brake piston is mounted so as to be adjustable in the direction of the longitudinal axis of the adjusting spindle.

[0027] A threaded tube of the at least one adjusting spindle has an external thread corresponding to an internal thread of the bridge.

[0028] The brake piston is designed as described above.

[0029] In an advantageous further development of the application device, it has exactly one brake piston arranged centrally on the bridge.

[0030] According to a further preferred embodiment, a bellows is attached to an outer surface of the support web of the pressure piece.

[0031] The formation of the support web on the pressure piece creates a particularly suitable mounting surface for such a bellows, which provides sealing protection for the threaded pipe.

[0032] In addition, the fastening of the bellows to this support web enables an extremely flat design (viewed in the direction of the longitudinal axis of the adjusting spindle), since the fixing of the bellows to the pressure piece takes place in the same plane as the fixing of the adjusting spindle to the pressure piece.

[0033] The disc brake according to the invention for a commercial vehicle comprises a brake disc, a brake carrier, a brake calliper displaceably guided on the brake carrier and brake pads arranged on both sides of the brake disc, which are displaceably arranged in respective pad shafts of the brake carrier parallel to a brake disc rotation axis, as well as an application device with which the brake pads can be pressed against the brake disc.

[0034] The clamping device is designed as described above.

[0035] A preferred embodiment of the invention is explained in more detail below with reference to the accompanying drawings.

[0036] They show: Fig. 1 a disc brake provided with an application device according to the prior art in a partially sectioned plan view Fig. 2 a sectional view through a brake piston known from the prior art with pins formed on the pressure piece and Fig. 3 one of the Fig. 2 corresponding sectional view through a variant of a brake piston according to the invention with bellows arranged thereon.

[0037] 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 brake piston, adjusting spindle, pressure piece, pin, application device, brake anchor plate, 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.

[0038] In Fig. 1 shows a disc brake known in principle from the prior art with an application device 5, a brake disc, a brake carrier 2 and a brake calliper 1 displaceably guided on the brake carrier 2.

[0039] The brake caliper 1 is held on the stationary brake carrier 2 so as to be axially displaceable relative to the brake disc 3 relative to a rotational axis of the brake disc 3. The brake application device 5 is positioned in the brake caliper 1 and has a pivotable, pneumatically or electromechanically actuated brake lever 6, which is supported on a bridge 7.

[0040] How to continue in Fig. As shown in Figure 1, two adjusting spindles 8 of respective brake pistons are rotatably mounted in the bridge 7. The adjusting spindles 8 of these brake pistons each have an external thread that engages a threaded hole in the bridge 7.

[0041] In addition to the adjusting spindle 8, each of the two brake pistons has a pressure piece 9 which is arranged at a respective end of the adjusting spindle 8 facing away from the brake lever 6.

[0042] In the event of braking, the pressure piece 9 is pressed against an action-side brake pad 4 by means of the application device 5, which leads to the brake pad 4 being pressed against the brake disc 3.

[0043] As the braking process continues, the reaction-side brake pad is also pressed against the opposite side of the brake disc 3 by moving the brake calliper 1.

[0044] As in Fig. 1, the brake piston consisting of adjusting spindle 8 and pressure piece 9 is designed here in such a way that the pressure piece 9 serves as a pin holder for receiving a pin formed on the adjusting spindle 8.

[0045] Fig. 2 shows an alternative variant of such a brake piston known from the prior art, in which a pin 12 is formed on the pressure piece 9, which is received in a corresponding pin receptacle in the spindle base 11 of the adjusting spindle 8.

[0046] Fig. Figure 3 shows a preferred embodiment of a brake piston 20 according to the invention. This brake piston 20 of a disc brake of a commercial vehicle also has an adjusting spindle 30 and a pressure piece 40. The adjusting spindle 30 also consists of a threaded tube 31 with an external thread 32 and a spindle base 35 with a central pin receptacle 34 and an annular end face 33 surrounding the pin receptacle 34.

[0047] The pressure piece 40 has a pressure surface 41 facing the action-side brake pad 4 (in the installed state) and a central pin 42 projecting into the pin receptacle 34 of the spindle base 35.

[0048] How Fig. 3, a support web 43 concentrically surrounding the pin 42 is formed on the pressure piece 40.

[0049] The annular end face 33 of the adjusting spindle 30 surrounding the pin receptacle 34 rests on a base 44 of the pressure piece 40 between the pin 42 and the support web 43.

[0050] As with the Fig. 3, a radial width b of the ring of the adjusting spindle 30 forming the annular end face 33 is at least 40% of the diameter d spanned by the annular end face 33 F of the spindle base 35.

[0051] This creates a significantly larger contact surface between the adjusting spindle 30 and the pressure piece 40 compared to the prior art.

[0052] Again Fig. 3, the diameter d F of the spindle base 35 at least 60% of the diameter d of the pressure surface 41 of the pressure piece 40.

[0053] This design of the spindle base 35 and the pressure surface 41 of the pressure piece 40 ensures that outer regions of the annular end face 33 of the adjusting spindle 30, viewed in the radial direction, come into contact with the pressure piece 40 very close to an outer edge 45 of the pressure surface 41 of the pressure piece 40, which significantly reduces the risk of the pressure piece 40 tilting relative to the adjusting spindle 30 compared to the brake pistons known from the prior art.

[0054] To further reduce the risk of tilting of the pressure piece 40 relative to the adjusting spindle 30, as shown in Fig. 3 is also shown, a height hz of the pin 42 viewed in the direction of the longitudinal axis A of the adjusting spindle 30, viewed from the bottom 44 of the pressure piece 40, into which the annular end face 33 of the adjusting spindle 30 rests, is at least 60% of the total height h D of the pressure piece 40.

[0055] By extending the pin 42, a significant improvement in the guidance of the pressure piece 40 in the pin receptacle 34 of the adjusting spindle 30 is achieved.

[0056] For a more extensive support of the pressure piece 40 on the adjusting spindle 30, the spindle base 35 is designed such that its diameter d F is larger than the diameter d G of the threaded tube 31 of the adjusting spindle 30.

[0057] In order to enable a simple decoupling of the rotary movement of the adjusting spindle 30 from the pressure piece 40, Fig. 3, a sliding sleeve 50 is arranged between an inner surface of the journal receptacle 34 of the spindle base 35 and an outer surface of the journal 42.

[0058] The sliding sleeve 50 can be caulked in a notch 46 on the outer surface of the pin 42 in order to achieve an axial fixation of the sliding sleeve 50 on the pressure piece 40.

[0059] A clamping device according to the invention can in principle be like the one in Fig. 1 shown application device, whereby here the brake piston 20 is used instead of the adjusting spindle 8 and the pressure piece 9.

[0060] In a preferred embodiment of such an application device, it has exactly one brake piston 20 arranged centrally on the bridge 7, so that instead of the Fig. 1 shown application device with two brake pistons, only one central brake piston 20 presses the action-side brake pad against the brake disc 3 in the event of braking.

[0061] How to continue in Fig. 3, a bellows 60 is attached to an outer surface of the support web 43 of the pressure piece 40.

[0062] The Fig. The bellows 60 shown in Figure 3 has a first end ring 61 and a second, smaller-diameter end ring 62. The smaller-diameter end ring 62 is secured here to the outer surface of the support web 43 of the pressure piece 40.

[0063] The bellows 60 further comprises a plurality of folds, each of which, in the relaxed position, has two flanks 64, 66 extending in opposite directions to one another, forming a bend 63, 65, 67. A first flank 64 adjoining the first end ring 61 and following a first bend 63 is dimensioned such that the adjoining bend 65 approximately terminates at the end face 68 of the second end ring 62 facing the contact surface 41 of the pressure piece 40.

[0064] As in Fig.3, viewed in the radial direction, the bellows 60, here the second end ring 62 of the bellows 60, the support web 43 of the pressure piece 40 and the spindle base 35 of the adjusting spindle 30 are arranged one behind the other in a common plane radially to the longitudinal axis A of the adjusting spindle 30.

[0065] This enables an extremely flat design (viewed in the direction of the longitudinal axis A of the adjusting spindle 30) of the pressure piece 40. List of reference symbols 1 brake caliper 2 brake carriers 3 brake disc 4 brake pad 5 Clamping device 6 brake levers 7 Bridge 8 adjusting spindle 9 Pressure piece 10 bellows 11 spindle base 12 cones 20 brake pistons 30 adjusting spindle 31 threaded pipe 32 external thread 33 Frontal surface 34 tenon holder 35 spindle base 36 outer edge 40 pressure piece 41 Pressure surface 42 cones 43 Support bridge 44 Floor 45 outer edge 46 Notch 50 sliding sleeve 60 bellows 61 first end ring 62 second end ring 63 turns 64 flank 65 bends 66 flank 67 bends 68 front side b Width of the frontal surface hz height of the tenon h D Height of the pressure piece d D Diameter of the contact surface of the pressure piece d F Diameter of the spindle base d G Diameter of the threaded pipe A Longitudinal axis

Claims

[1] Brake piston (20) of a disc brake of a commercial vehicle, comprising - an adjusting spindle (30) and - a pressure piece (40), - wherein the adjusting spindle (30) has a threaded tube (31) with an external thread (32) and a spindle base (35) with a central pin receptacle (34) and an annular end face (33) surrounding the pin receptacle (34), - wherein the pressure piece (40) has a pressure surface (41) facing an action-side brake pad (4) and a central pin (42) projecting into the pin receptacle (34) of the spindle base (35), characterized by , that - a support web (43) concentrically surrounding the pin (42) is formed on the pressure piece (40), wherein the annular end face (33) of the spindle base (35) surrounding the pin receptacle (34) rests on a base (44) of the pressure piece (40) between the pin (42) and the support web (43), - where the diameter (d F) of the spindle base (35) is at least 60% of the outer diameter (d) of the pressure surface (41) of the pressure piece (40). [2] Brake piston (20) according to claim 1, characterized by that a radial width (b) of the ring of the adjusting spindle (30) forming the annular end face (33) is at least 40% of the diameter (d F ) of the spindle base (35). [3] Brake piston (20) according to one of the preceding claims, characterized by that a height (hz) of the pin (42) viewed in the direction of the longitudinal axis (A) of the adjusting spindle (30), viewed from the bottom (44) of the pressure piece (40), is at least 60% of the total height (h D ) of the pressure piece (40). [4] Brake piston (20) according to one of the preceding claims, characterized by that the diameter (d F ) of the spindle base (35) is larger than a diameter (d G ) of the threaded tube (61). [5] Brake piston (20) according to one of the preceding claims, characterized by that a sliding sleeve (50) is arranged between an inner surface of the journal receptacle (34) of the spindle base (35) and an outer surface of the journal (42). [6] Application device (5) arranged in a brake calliper (1) of a disc brake for a commercial vehicle, comprising - a brake lever (6), - a bridge (7) on which the brake lever (6) is supported, - at least one brake piston (20), - wherein at least one adjusting spindle (30) of the at least one brake piston (20) is mounted on the end of the bridge (7) facing away from the brake lever (6) so as to be adjustable in the direction of the longitudinal axis of the adjusting spindle (30), - wherein a threaded tube (31) of the at least one adjusting spindle (30) has an external thread (32) corresponding to an internal thread of the bridge (7), characterized by , that - the brake piston (20) is designed according to one of the preceding claims. [7] Application device according to claim 6, characterized by that the application device (5) has exactly one brake piston (20) arranged centrally on the bridge (7). [8] Application device according to claim 6 or 7, characterized by that a bellows (60) is attached to an outer surface of the support web (43) of the pressure piece (40). [9] Disc brake for a commercial vehicle, comprising - a brake disc (3), - a brake carrier (2), - a brake calliper (1) which is slidably guided on the brake carrier (2), - brake pads (4) arranged on both sides of the brake disc (3), which are arranged in respective pad shafts of the brake carrier (2) so as to be displaceable parallel to a brake disc rotation axis, - an application device (5) with which the brake pads (4) can be pressed against the brake disc (3), characterized by , that - the application device (5) is designed according to one of the preceding claims 6 to 8.

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