Disc brake for a utility vehicle
Patent Information
- Application Number
- EP2023764275
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-09-14
- Filing Date
- 2023-08-29
- Publication Date
- 2025-07-23
AI Technical Summary
Sliding caliper disc brakes in commercial vehicles experience residual grinding moments after braking, leading to increased fuel consumption and premature wear of components due to the brake pads resting against the disc without pressure during ferry operations, which existing solutions do not adequately address.
A disc brake design featuring a sliding caliper with a restoring device using springs that exert axial and/or tangential torque on lining carrier plates, securing the brake pads with a pad retaining bracket and angled end regions for improved attachment and reduced oblique wear, enhancing the active return of brake linings after braking.
The design effectively reduces oblique wear of brake pads and improves the secure attachment of return springs, minimizing residual grinding moments and wear on brake components, thereby reducing fuel consumption and extending component lifespan.
Smart Images
Figure 1.1
Abstract
Description
[0001] Disc brake for a commercial vehicle
[0002] DESCRIPTION
[0003] The present invention relates to a disc brake for a commercial vehicle according to the preamble of claim 1.
[0004] In a sliding-caliper disc brake, a pneumatically or electric-motor-operated brake application device presses an action-side brake pad against a brake disc during braking. As the braking process continues, the brake caliper is displaced relative to the brake disc in the opposite direction to the application of the action-side brake pad, driving and pressing the opposing, reaction-side brake pad against the other side of the brake disc.
[0005] After the brake is released, the brake calliper of the well-known disc brake remains in this position in which the brake pads, or at least the reaction-side brake pad, rest against the brake disc without pressure but in a grinding manner.
[0006] The resulting residual friction torque of the brake pads during ferry operation has a detrimental effect, leading to increased fuel consumption and premature wear of the components involved, namely the brake disc and brake pads. While ferry operation also causes the brake pads to loosen, this is not always sufficient to effectively prevent the aforementioned residual friction torque.
[0007] Various solutions to address this problem are already known from the state of the art. One example is DE 10 2019 131 840 A1, in which the spring legs of a return device are held by their ends against opposing brake pads, thus reliably releasing the brake pads on both sides of a brake disc from the brake disc after the braking action has been completed.
[0008] The object of the present invention is to further develop a disc brake of the generic type in such a way that the return springs for actively returning the brake pads resting on the brake disc after a braking operation are further improved with regard to their securing to the brake pads and with regard to an expanded functionality.
[0009] This object is achieved by a disc brake having the features of claim 1.
[0010] The disc brake according to the invention for a commercial vehicle has a brake disc, a brake caliper designed as a sliding caliper that overlaps the brake disc, a stationary brake carrier to which the brake caliper is fastened, and brake pads each having a pad carrier plate and a friction lining fastened thereon, which brake pads are arranged on both sides of the brake disc in the brake caliper and can be pressed against opposite sides of the brake disc.
[0011] The brake calliper has a central opening above the brake disc, which is spanned by a pad retaining bracket, securing the brake pads in a pad slot of the brake carrier.
[0012] An action-side brake pad can be pressed against the brake disc by means of an application device via at least one brake piston and a reaction-side brake pad can be pressed against the brake disc via the brake calliper.
[0013] The disc brake further comprises a return device with at least one return spring acting on the pad carrier plates of the brake pads for actively returning the brake pads resting on the brake disc after a braking operation.
[0014] The end regions of this at least one return spring are designed in such a way that they act on the pad carrier plates of the brake pads by exerting a torque that is axial and / or tangential to the axis of rotation of the brake disc.
[0015] The design of this interface between the end regions of the return spring and the two brake lining plates in such a way that an axial and / or tangential tilting moment is exerted on the brake lining plates has the advantage of a more robust attachment of the return spring to the brake lining plates. Furthermore, such a tilting moment exerted on the brake lining causes a tilting moment on the brake lining, which contributes to a reduction in angular wear.
[0016] Advantageous embodiments of the invention are the subject of the subclaims.
[0017] According to an advantageous embodiment, the return device comprises two such return springs. The return springs are preferably arranged in an area close to the side edges of the lining carrier plates.
[0018] According to a further advantageous embodiment, the at least one return spring has a base section, two legs angled relative to the base section and end regions bent relative to the legs.
[0019] A first end region protrudes into a receptacle of the pad carrier plate of the action-side brake pad and a second end region of the return spring protrudes into a receptacle of the pad carrier plate of the reaction-side brake pad.
[0020] The longitudinal axes of the end areas are aligned at an acute angle to the longitudinal axes of the supports of the lining carrier plates.
[0021] The acute-angled alignment of the longitudinal axes of the end regions of the return spring relative to the longitudinal axes of the receptacles of the lining carrier plates enables a defined point of contact between the end regions of the return spring and the receptacles of the lining carrier plates, whereby the coefficient of friction between the adjacent components is advantageously increased compared to a parallel arrangement.
[0022] According to an advantageous further development, the receptacles in the lining carrier plates are open to a radially outer front edge of the lining carrier plates.
[0023] This makes it particularly easy to install the return springs in the holders of the lining carrier plates.
[0024] According to a further advantageous development, the receptacles in the lining carrier plates have a recess extending at an angle to the longitudinal axis of the receptacles, into which a cranking of the end regions of the return spring is understood.
[0025] This provides a further improvement in the retention of the return spring in the pads' support plates.
[0026] According to a further preferred embodiment, the longitudinal axes of the end regions of the return spring or the longitudinal axes of the receptacles of the lining carrier plates in which the end regions of a return spring are accommodated are aligned so as to run towards one another or away from one another when viewed in the direction of the axis of rotation of the brake disc.
[0027] Depending on the requirements, diagonal wear of the friction linings of the brake pads can be reduced by inclining the radially upper or lower edge of the brake pad away from the brake disc.
[0028] According to an alternative embodiment, the longitudinal axes of the end regions of the return spring or the longitudinal axes of the receptacles of the lining carrier plates in which the end regions of a return spring are accommodated are aligned parallel to one another when viewed in the direction of the axis of rotation of the brake disc.
[0029] According to a further preferred embodiment, an inner wall delimiting the receptacles in the lining carrier plates is provided with at least one groove.
[0030] The formation of such a groove in the mounts also enables an increased coefficient of friction between the components lying against each other.
[0031] According to a further preferred embodiment variant, a support contour protrudes from the outer surface of the end regions of the return spring, which support contour, in the mounted state of the return spring, rests on an edge of the lining carrier plate surrounding an inlet of the respective receptacle.
[0032] Such a support contour ensures a defined penetration depth of the end regions of the return spring. According to a further advantageous embodiment of the invention, the base section of the return spring, when mounted, rests against an underside of the pad retaining bracket facing the rotational axis of the brake disc.
[0033] The return springs are preferably made of a spring steel wire, in particular with a round cross-section.
[0034] Polygonal cross-sections of the return spring are also conceivable.
[0035] Preferred embodiments of the invention are explained in more detail below with reference to the accompanying drawings. They show:
[0036] Figure 1 is an isometric view of a variant of a disc brake according to the invention with ends of two return springs engaging the lining carrier plates of brake pads,
[0037] Figure 2 shows a representation of the disc brake corresponding to Figure 1 with the pad retaining bracket omitted,
[0038] Figure 3 is an isometric view of the two brake pads and the return springs arranged on them,
[0039] Figure 4 is a sectional view of the brake pads with end regions of one of the return springs projecting into the receptacles of the pad carrier plates, with the end regions of the return spring aligned away from each other when viewed in the direction of the axis of rotation of the brake disc,
[0040] Figure 5 is a sectional view through the disc brake in the same plane as Figure 4 with the end regions of the return spring aligned parallel to each other,
[0041] Figure 6 is a representation corresponding to Figure 4 with the end regions of the return spring converging towards one another, viewed in the direction of the axis of rotation of the brake disc. Figure 7 is a sectional view through the action-side brake pad to show a tangentially inclined end region of one of the return springs in a receptacle of the pad carrier plate.
[0042] Figure 8 is a representation analogous to Figure 7 with a vertically formed end region of the return spring and an oblique receptacle in the lining carrier plate in the tangential direction.
[0043] 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 disc brake, brake disc, brake pad, pad carrier plate, return spring, 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.
[0044] In Figure 1, reference numeral 1 denotes an embodiment of a disc brake 1 according to the invention for a commercial vehicle. The disc brake 1 comprises a brake disc 2 and a brake caliper 3 that engages the brake disc 2. The brake disc 2 rotates with a wheel (not shown here) of a vehicle while driving. Thus, a brake disc rotation axis D coincides with the wheel axis when installed.
[0045] The brake caliper 3 is connected to a brake carrier 4 so as to be axially displaceable in the direction of the brake disc rotation axis D. For this purpose, the brake caliper 1 is mounted on guide rails (not shown) that are connected to the brake carrier 4, which is fixedly mounted on the commercial vehicle. The brake disc rotates in a circumferential direction while driving.
[0046] The brake caliper 3 comprises an application section 32, a caliper back 33, and two tension struts 34. The application section 32 accommodates an application device (not shown) of the disc brake 1. The application section 32 runs with one side parallel to the plane of the brake disc 2 on one side of the brake disc 2. On the other side of the brake disc 2, the caliper back 33 is arranged - also running parallel to the brake disc 2. The caliper back 33 is connected to the application section 32 at one end each by a tension strut 34. The tension struts 34 run essentially at right angles to the application section 32 and to the caliper back 33. In this arrangement, the application section 32, the caliper back 33, and the tension struts 34 define a central opening 31 between them, which spans the brake disc 2.
[0047] The opening 31 has an imaginary longitudinal centerline, which lies in the plane of the brake disc 2 and connects the imaginary centers of the tension struts 34. Furthermore, the opening 31 has another imaginary transverse centerline, which connects an imaginary center of the clamping section 32 with an imaginary center of the caliper back 33. The longitudinal centerline and the transverse centerline intersect at an imaginary center point, which is referred to here as the virtual center of the central opening 34. The longitudinal centerline and the transverse centerline thus define an imaginary plane of the central opening 31, which lies radially to the brake disc 2.
[0048] Brake pads 5, 6 are inserted into the brake carrier 4, which can be pressed against the brake disc 2 on both sides during braking. Each brake pad 5, 6 has a pad carrier plate 51, 61 and a friction lining 52, 62 applied thereto on the side facing the brake disc 2, which is pressed against the brake disc 2 during braking.
[0049] The brake pads 5, 6 are accessible through the central opening 31 for replacement and maintenance. They can be inserted into and removed from their corresponding pad wells of the brake carrier 4 through the central – somewhat rectangular – opening 31. The pad wells are each bounded laterally by so-called brake carrier horns of the brake carrier 4.
[0050] During braking, a brake lever, which can be arranged in a dome of the brake calliper 3, acts on an application device which is arranged in the application section 32 of the brake calliper 3.
[0051] The action-side or application-side brake pad 5 initially contacts the brake disc 2. As the application process continues, the brake calliper 3 is displaced in the opposite direction by the reaction forces occurring, taking with it the reaction-side brake pad 6, until the latter also comes into frictional contact with the brake disc 2 and thus brakes the wheel with which the brake disc 2 rotates, and thus the commercial vehicle.
[0052] After the brake is released, the two opposing brake pads 5, 6 are released from the brake disc 2 by a return device to such an extent that the latter is no longer in contact with the brake pads 5, 6.
[0053] The return device has at least one return spring 8, which exerts its force acting counter to the application direction.
[0054] As shown in Figures 1 and 2, the return device of the disc brake 1 has two return springs 8. Both return springs 8 are preferably designed as identical parts.
[0055] As can be seen in particular in Figure 3, which shows the two brake pads 5, 6 with return springs 8 arranged on them, each of the return springs 8 has an approximately U-shaped base section 81, from the ends of which extend parallel to one another a leg 82a, 82b extends which is angled towards these.
[0056] Each of the legs 82a, 82b has a straight region and a curved region, so that the ends of the angled legs 82a, 82b are aligned approximately parallel to the axis of rotation D of the brake disc 2.
[0057] From these angled legs 82a, 82b there extends a bent end region 83a, 83b which extends into a receptacle 53, 63 in a radially outer end edge 56, 66 of the lining carrier plate 51, 61.
[0058] The cross section of the receptacles 53, 63 is slightly larger than the cross section of the end regions 83a, 83b of the return spring 8. Slightly larger here means a difference in diameter of preferably 10 - 50 percent.
[0059] The differently dimensioned diameters enable the longitudinal axes LE of the end regions 83a, 83b to be aligned at an acute angle to the longitudinal axes LA of the receptacles 53, 63 of the lining carrier plates 51, 61, as shown in Figures 4-8. In the embodiment shown in Figure 4, the longitudinal axes LE of the end regions 83a, 83b of the return springs 8 are aligned so as to diverge from one another, viewed in the direction of the rotational axis D of the brake disc 2. The receptacles 53, 63 in the lining carrier plates 51, 61 are aligned parallel to the contact surface 57, 67 of the respective lining carrier plate 51, 61.
[0060] Due to this acute-angled alignment of the end regions 83a, 83b relative to the receptacles 53, 63, in addition to their main task of pressing the two brake pads 5, 6 apart from the brake disc 2 after the braking operation, the return springs 8 exert a tilting moment M, by means of which the two brake pads 5, 6 are aligned with one another in such a way that an upper brake pad edge of the brake pads 5 that is radially removed from the axis of rotation D of the brake disc 2 is held slightly closer to the brake disc 2 than a lower brake pad edge of the brake pads 5, 6 that is radially closer to the axis of rotation D of the brake disc 2.
[0061] Furthermore, due to the alignment of the end regions 83a, 83b of the return springs 8 shown in Figure 4, the force F with which the return springs 8 press the two brake pads 5, 6 apart is introduced near a center of gravity of the brake pad, viewed in the radial direction.
[0062] By using two such return springs 8, which act in a tangential direction near the side edges 55, 65 of the pad carrier plates 51, 61, it also results that the force resulting from these two return springs 8 also acts near or even in the center of gravity of the brake pad, in this case viewed in a tangential direction.
[0063] Depending on the direction of the radial oblique wear of the brake pads 5, 6, which is partly due to the design, it is also conceivable, as shown by way of example in Figure 5, to align the longitudinal axes of the end regions 83a, 83b of the return spring 8, viewed in the direction of the axis of rotation D of the brake disc 2, parallel to one another.
[0064] This means that in the embodiment shown in Figure 5, the reaction-side brake pad causes the lower edge of the brake pad to tilt away from the brake disc 2 due to the force effect of the return springs 8, while the reaction-side brake pad 6 causes the upper edge of the brake pad to tilt away from the brake disc 2 due to the tilting moment applied by the return springs 8.
[0065] Figure 6 shows a further embodiment variant in which the longitudinal axes LE of the end regions 83a, 83b of the return springs 8 are aligned converging towards one another when viewed in the direction of the axis of rotation D of the brake disc 2, so that in this case the tilting moment M caused by the return springs 8 will tilt both the action-side brake pad 5 and the reaction-side brake pad 6 in such a way that the upper edge of the brake pad tilts away from the brake disc 2.
[0066] Furthermore, due to the contact of the end regions 83a, 83b with inner edge regions remote from the brake disc 2 at the entrance of the respective receptacle 53, 63, a stronger tilting moment is caused compared to the embodiment shown in Figure 4, due to the height of the point of application of the end region 83a, 83b of the return spring 8 at the entrance of the receptacle 53, 63 of the lining carrier plate 51, 61.
[0067] In the embodiment shown in Figure 7, the longitudinal axes L of the end regions 83a, 83b of the return springs 8 are aligned such that the acute-angled arrangement between the end regions 83a, 83b of the return springs 8 and the receptacles 53, 63 is angled in the tangential direction.
[0068] Figure 8 shows, by way of example, a kinematic reversal of the acute-angled alignment between the end regions 83a, 83b of the return spring 8 and the receptacles 53, 63 in the lining carrier plates 51, 61, in which the longitudinal axes LE of the end region 83a of the return spring 8 is aligned almost vertically, while the receptacle 53 is formed inclined in the direction of the side edge 55 in the lining carrier plate 51.
[0069] The same kinematic reversal is also conceivable for the embodiments shown in Figures 4-6, wherein the drilling of oblique holes in the lining carrier plate 51, 61 from the plane parallel to the pressure surface 57, 67 of the lining carrier plates 51, 61 is subject to narrower limits than the drilling of an oblique hole as shown in the embodiment of Figure 8. In all of the embodiments shown in the figures, the receptacles 53, 63 are made in the lining carrier plates 51, 61 in an edge region of the lining carrier plates 51, 61 which is close to the side edges 55, 65, viewed in the tangential direction.
[0070] The receptacles 53, 63 are preferably provided tangentially outside respective lugs 54 of the pad carrier plates 51, which serve to guide pad retaining springs 9, which in the embodiment of the disc brake 1 shown here are secured to the pad carrier plate 51, 61 of the respective brake pad 5, 6 by means of hoods 10 arranged centrally, viewed in the tangential direction.
[0071] To further secure the return springs 8 to the lining carrier plates 51, 61, it can be provided that the receptacles 53, 63 in the lining carrier plates 51, 61 have a recess extending at an angle to the longitudinal axis LA of the receptacles 53, 63, into which a crank protrudes at the end regions 83a, 83b of the return springs 8.
[0072] It is also conceivable that an inner wall delimiting the receptacles 53, 63 in the lining carrier plates 51, 61 has one or more grooves by means of which the frictional engagement between the end regions 83a, 83b of the return springs 8 in the receptacles 53, 63 of the lining carrier plates 51, 61 is further increased.
[0073] It is also conceivable that a support contour protrudes from the outer surface of the end regions 83a, 83b of the return springs 8, which support contour, in the mounted state of the return spring 8, rests on an edge of the lining carrier plate 51, 61 surrounding an inlet of the respective receptacle 53, 63.
[0074] The return springs 8 are preferably made of spring wire, in particular with a round cross-section. Return springs 8 with a different cross-section, for example, a polygonal cross-section, are also conceivable. This is made possible in a simple manner, in particular, by the cross-section of the end regions 83a, 83b of the return spring 8 being smaller than the cross-section of the receptacles 53, 63 in the lining carrier plates 51, 61. LIST OF REFERENCE SYMBOLS
[0075] 1 disc brake
[0076] 2 brake discs
[0077] 21 , 22 Friction surface
[0078] 3 brake caliper
[0079] 31 Opening
[0080] 32 clamping section
[0081] 33 saddle back
[0082] 4 brake carriers
[0083] 41 Covering shaft
[0084] 5 action-side brake pad
[0085] 51 Pad carrier plate
[0086] 52 friction lining
[0087] 53 recording
[0088] 54 Nose
[0089] 55 side edge
[0090] 56 top edge
[0091] 57 pressure surface
[0092] 6 reaction-side brake pad
[0093] 61 lining carrier plate
[0094] 62 friction lining
[0095] 63 recording
[0096] 64 Nose
[0097] 65 side edge
[0098] 66 top edge
[0099] 67 pressure surface
[0100] 7 Pad retaining brackets
[0101] 8 Return spring 81 Base section
[0102] 82a first leg
[0103] 82b second leg
[0104] 83a first end area
[0105] 83b second end area
[0106] 9 Pad retaining spring
[0107] 10 hood
[0108] D axis of rotation
[0109] LE Longitudinal axis of the end of the return spring
[0110] LA Longitudinal axis of the recess of the lining carrier plate
[0111] F Force
[0112] M Tilting moment
Claims
Claims Disc brake (1) for a commercial vehicle, comprising - a brake disc (2), - a brake calliper (3) designed as a sliding calliper, which overlaps the brake disc (2), - a stationary brake carrier (4) to which the brake calliper (3) is attached, - brake pads (5, 6) each having a pad carrier plate (51, 61) and a friction lining (52, 62) fastened thereon, which are arranged on both sides of the brake disc (2) in the brake calliper (3) and can be pressed against opposite sides of the brake disc (2), - wherein the brake calliper (3) has a central opening (31) above the brake disc (2), which, securing the brake pads (5, 6) in a pad shaft (41) of the brake carrier (4), is spanned by a pad retaining bracket (7), - wherein an action-side brake pad (5) can be pressed against the brake disc (2) by means of an application device via at least one brake piston and a reaction-side brake pad (6) can be pressed against the brake disc (2) via the brake calliper (3), - a return device with at least one return spring (8) acting on the lining carrier plates (51, 61) of the brake linings (5, 6) for the active return of the brake linings (5, 6) resting on the brake disc (2) after a braking operation, characterized in that - End regions (83a, 83b) of the at least one return spring (8) engage the lining carrier plates (51, 61) of the brake pads (5, 6) by exerting a torque axial and / or tangential to the rotational axis of the brake disc. Disc brake (1) according to claim 1, characterized in that the return device has two return springs (8).
3. Disc brake (1) according to claim 1 or 2, characterized in that the at least one return spring (8) has a base section (81), two legs (82a, 82b) angled relative to the base section (81) and end regions (83a, 83b) bent relative to the legs (82a, 82b), wherein a first end region (83a) projects into a receptacle (53) of the pad carrier plate (51) of the action-side brake pad (5) and a second end region (83b) projects into a receptacle (63) of the pad carrier plate (61) of the reaction-side brake pad (6), wherein longitudinal axes (LE) of the end regions (83a, 83b) are aligned at an acute angle to longitudinal axes (LA) of the receptacles (53, 63) of the pad carrier plates (51, 61).
4. Disc brake (1) according to claim 3, characterized in that the receptacles (53, 63) in the lining carrier plates (51, 61) are open to a radially outer end edge (56, 66) of the lining carrier plates (51, 61).
5. Disc brake (1) according to claim 3 or 4, characterized in that the receptacles (53, 63) in the lining carrier plates (51, 61) have a recess extending at an angle to the longitudinal axis (LA) of the receptacles (53, 63), into which a crank of the end regions (83a, 83b) of the return spring (8) projects.
6. Disc brake (1) according to one of claims 3 to 5, characterized in that the longitudinal axes (LE) of the end regions (83a, 83b) of the return spring (8) or the longitudinal axes (LA) of the receptacles (53, 63) of the lining carrier plates (51, 61), in which the end regions (83a, 83b) of a return spring (8) are received, are aligned so as to converge towards one another or to diverge from one another when viewed in the direction of the axis of rotation (D) of the brake disc (2).
7. Disc brake (1) according to one of claims 3 to 5, characterized in that the longitudinal axes of the end regions (83a, 83b) of the return spring (8) or the longitudinal axes of the receptacles (53, 63) of the lining carrier plates (51, 61), in which the end regions (83a, 83b) of a return spring (8) are received, are aligned parallel to one another when viewed in the direction of the axis of rotation (D) of the brake disc (2).
8. Disc brake (1) according to one of claims 3 to 7, characterized in that an inner wall delimiting the receptacles (53, 63) in the lining carrier plates (51, 61) is provided with at least one groove.
9. Disc brake (1) according to one of claims 3 to 8, characterized in that a support contour protrudes from the outer surface of the end regions (83a, 83b) of the return spring (8), which support contour, in the assembled state of the return spring (8), rests on an edge of the lining carrier plate (51, 61) surrounding an inlet of the respective receptacle (53, 63).
10. Disc brake (1) according to one of claims 3 to 9, characterized in that the base section (81) of the return spring (8) is supported in the mounted state on an underside of the pad retaining bracket facing the axis of rotation of the brake disc (2).
11. Disc brake (1) according to one of the preceding claims, characterized in that the respective return spring (8) is made of a spring steel wire, in particular with a round cross-section.