Disc brake, use of the disc brake and method for applying the disc brake

Abstract

The invention relates to a disc brake (1) for a motor vehicle and / or bus, having an electric brake generator, comprising a brake disc (2) having an axis of rotation A and a set of brake pads (6) for applying the disc brake; wherein the disc brake (1) comprises a brake caliper (3) designed as a sliding caliper; wherein the disc brake (1) comprises an application device (8) for actuating the brake pads (6), which is arranged in a receiving space (7) of a brake caliper (3); wherein the disc brake (1) also comprises an actuating element for introducing force into the application device (8) with an actuating force, wherein the application device (8) comprises a brake lever (10), on which the actuating element acts with the actuating force and wherein the application device (8) acts on the brake pads (6) with an application force along an application axis Z, wherein the length of the brake lever (10) is selected such that the transmission ratio between actuating force and application force is between 1:15.60 and 1:16.45, preferably with a brake stroke of 2.5 to 4 mm.

Description

[0001] DESCRIPTION

[0002] Disc brake, use of the disc brake and method for applying the disc brake

[0003] The present invention relates to a disc brake for a motor vehicle and / or bus with an electric generator brake, as well as a use of the disc brake in a motor vehicle and / or bus with an electric generator brake and a method for applying the disc brake.

[0004] Disc brakes require design compromises at various points to achieve a specific application force. Due to the limited space available for the overall design of a disc brake in a vehicle, brake levers are designed to allow application by pivoting over a large angle and creating so-called progressive lines of force, even at high speeds.

[0005] Due to cooperative braking behavior, for example in electrically powered vehicles, lower forces can act on the disc brakes, so that these compromises can be eliminated in favor of an optimized and compact design.

[0006] The object of the present invention is therefore to adapt the design of the disc brake to the requirements of electrically powered motor vehicles or buses.

[0007] The invention solves this problem by the subject matter of claim 1.

[0008] A disc brake according to the invention is intended for use in a motor vehicle and / or bus with an electric generator brake. It comprises a brake disc with a rotational axis A and a set of brake pads for applying the brake disc. It also has a brake caliper designed as a sliding caliper. Furthermore, it has an application device for actuating the brake pads, which is arranged in a receiving space of a brake caliper. The disc brake also has an actuating element for introducing force into the application device with an actuating force. This can preferably be a brake cylinder, in particular a pneumatic brake cylinder.

[0009] The brake application device also has a brake lever, onto which the actuating element exerts the actuating force. The brake application device exerts an application force on the brake pads along an application axis.

[0010] According to the invention, the length of the brake lever is selected such that the transmission ratio between actuating force and clamping force is between 1:15.60 and 1:16.45. This transmission ratio is particularly preferred for a bridge stroke of 2.5 to 4 mm.

[0011] This transmission ratio is higher than that of conventional disc brakes of this type and has the advantage that individual components, particularly the actuating element and the brake cylinder, can be made smaller. The resulting space, particularly in the axial direction, can be used to increase the size of batteries or similar devices.

[0012] Advantageous embodiments of the disc brake are the subject of the subclaims.

[0013] Furthermore, the brake lever can have a spherical cap for accommodating an actuating piston of the actuating element and also a curved rolling surface along which the brake lever rolls against a rolling bearing in the receiving space of the brake caliper. The distance between the center of curvature of the spherical cap of the brake lever and the center of curvature of the rolling surface of the brake lever is between 78 and 82 mm. Such an enlarged brake lever allows for a reduction or complete elimination of the occurrence of progressive force lines during the force development during braking, which is particularly advantageous for ABS systems.

[0014] The application device has the aforementioned roller bearing for pivotally supporting the brake lever. The brake lever and / or the roller bearing has means for limiting the pivot angle, the means being arranged such that the pivot angle is limited to less than 90°, preferably less than 88°. Corresponding means can be found, for example, in EP 2 896 851 B1. This has the advantage that the height of the receiving space can be reduced. The resulting space can be used to improve stability by thickening the walls.

[0015] In a preferred variant, the brake caliper can have an installation opening with axially extending caliper struts on the edge. The caliper struts have a radial thickness of more than 13 mm, preferably 14-17 mm, particularly preferably 15.5 mm + / - 1 mm. These radial thicknesses enable better caliper stability and lower mechanical elasticity of the entire system.

[0016] The brake caliper can also have a caliper back, with no additional element protruding radially from the back that spans the installation opening in the axial direction. This can also save installation space or achieve miniaturization.

[0017] The disc brake can have a brake carrier with pad recesses, with the pad recesses featuring guide pockets on the edges to hold and guide the brake pads. This eliminates the need for a bracket at the installation opening, which also facilitates a compact design.

[0018] The guide pockets are advantageously formed by projections that protrude into the shaft lining at the edge of the shaft lining. Higher lateral forces pose a risk of deformation of these projections.

[0019] However, such high lateral forces are prevented from the outset by cooperative braking in electrically powered vehicles.

[0020] Further advantages arise from lowering the disc brake in relation to the brake disc axis by 8.5 mm, which makes it possible to provide the installation space through the lever and to increase the transmission ratio while simultaneously reducing the actuation travel of the cylinder.

[0021] An additional improvement is achieved by allowing the actuator flange to be located within the rim contour, thus reducing the axial space required for the disc brake with actuator. This frees up space on the axle in the vehicle that can be used by the drive or batteries. An additional reduction in the space required for the disc brake is achieved by positioning the application axis at a distance X parallel to the rotation axis, with the ratio of the distance X to the radial thickness of the seat stays being between 2.5 and 8.5 mm.

[0022] The invention also provides for the use of the disc brake according to the invention in a motor vehicle and / or bus with an electric generator brake which performs cooperative braking simultaneously with the disc brake.

[0023] Also according to the invention is a method for applying a disc brake according to the invention, wherein the brake lever is pivoted during the application process over the entire service life of the brake at a pivot angle of less than 90°, preferably less than 88°.

[0024] The invention is described in more detail below using exemplary embodiments with reference to the drawings, in which further advantageous variants and embodiments are also discussed. It should be emphasized that the exemplary embodiments discussed below are not intended to be exhaustive descriptions of the invention, but that variants and equivalents not shown are also feasible and fall within the scope of the claims. They show:

[0025] Fig.1 is a perspective view of a disc brake according to the invention;

[0026] Fig. 2 is a side view of the disc brake of Fig. 1;

[0027] Fig. 3 is a sectional view of the disc brake of Figs. 1 and 2;

[0028] Fig. 4 Detailed view of Fig. 3 and

[0029] Fig. 5 a perspective view of the brake carrier of the disc brake.

[0030] Fig. 6 is a further perspective view of the brake carrier of Fig. 5 with brake pads inserted; and Fig. 7 is a further perspective view of Figs. 5 and 6 from a different direction with brake pads inserted.

[0031] Fig. 8 Installation of the disc brake within the rim contour

[0032] The present invention relates to a disc brake for motor vehicles and buses that utilize electric generator brakes, in which an electric motor in generator mode generates electrical energy during braking. The disc brake according to the invention itself can be actuated in a conventional manner, e.g., as a pneumatic brake or another actuation method.

[0033] The aforementioned vehicles are thus braked cooperatively. The disc brake according to the invention is adapted for cooperative braking.

[0034] According to Fig. 1-4, the disc brake 1 has, in a manner known per se, a brake disc 2 with a rotation axis A, which is used as a reference axis for defining a radial direction.

[0035] The brake disc 2 is spanned by a brake caliper 3. This is typically made of cast iron and can be constructed as a single piece or from multiple bolted components. However, a single-piece design of the brake caliper 3 is preferred. The brake caliper is preferably designed as a sliding caliper and is attached to a vehicle-mounted brake carrier 4 so that it can be axially displaced parallel to the rotation axis A.

[0036] The brake carrier 4 has two pad shafts 5 for arranging two brake pads 6. The brake pads 6 rest on the brake disc 2 on both sides, frictionally engaging them during braking.

[0037] The brake caliper 3 has a receiving space 7 in which an application device 8 is positioned, with a brake lever 10 which can be actuated via a brake cylinder 9 and which is designed as an eccentric 11 at the end and rests on a bridge 12 in which adjusting spindles 22 are mounted, via which the associated brake pad 6 can be pressed against the brake disc 2. The longitudinal axis of the adjusting spindles 22 defines an application axis Z. An actuating piston 20 of the brake cylinder 9 lies in a calotte 19 of the brake lever 10. The brake caliper 3 is thereby displaced in such a way that the opposite, reaction-side brake pad 6 is pressed against the other side of the brake disc 2, with this reaction-side brake pad 6 resting against a caliper back 13 of the brake caliper 3.

[0038] For mounting the functional parts located in the receiving space 7, an assembly opening 14 is provided on the side facing the action-side brake pad 4, which is closed by a closure plate 15, wherein the two adjusting spindles mentioned pass through this closure plate 15.

[0039] In the exemplary embodiment, the eccentric 11 rests on the side opposite the bridge 12 against a caliper head 16 of the brake caliper 1, in areas that are formed as semicircular support surfaces 17 over an angular range of approximately 180°. To enable easy pivoting of the brake lever 6, roller bearings 18 are arranged between the support surfaces 17 and the eccentric 11. The design-related displaceability of this bridge 12 within the brake 1, particularly with respect to the brake carrier 4, is preferably 2.5-4 mm.

[0040] According to the present invention, due to cooperative braking at higher speeds, a reduced initial braking force can be applied. This allows the design of the disc brake to be modified in favor of smaller dimensions.

[0041] The present invention is based on the idea of ​​bringing the application point of the brake lever 10 for applying the brake pads 6 and thus the application axis Z closer to the rotation axis A. This allows the brake lever 10 to be made longer overall. The length L of the brake lever 10 can be between 78 and 82 mm relative to the center point 201 of the curvature of the calotte 19 and to the center point 202 of the curvature of the rolling surface 50 along which the brake lever 10 rolls on the rolling bearing 12. This is particularly highlighted in Fig. 4. The pivoting path 51 corresponding to the rolling surface 50 is highlighted and has been removed from the plane of the page. A brake lever of this length has not been known for brakes to date. The extended lever reduces the necessary actuating force. Accordingly, the length or dimensions of the brake cylinder 9 and / or another actuating element of the disc brake can be significantly reduced.This creates additional space in the axial direction within a vehicle for the arrangement of electric batteries or the like.

[0042] At the same time, the ratio of the actuating force applied by the brake cylinder 9 to the clamping force exerted on the brake pads changes to a range between 1:15.60 and 1:16.45. This ratio allows for a reduction in the pivot angle and thus also in the space required for the pivoting movement of the brake lever 10. If the distance between the brake lever and the brake pads is known, the optimal length of the brake lever can be calculated using trigonometric calculations from the aforementioned ratio.

[0043] The pivoting movement of the brake lever is divided into the so-called idle stroke, the operating stroke and the stroke reserve.

[0044] The idle stroke refers to the stroke required to bridge the brake pad clearance. Very little force is required to overcome this. This is followed by the actuation stroke for applying the brake and a stroke reserve, which is maintained due to wear and to maintain the required application force. The stroke reserve is measured by the elasticity of the application device 8, i.e., how much the application device 8 elastically yields upon actuation. Due to the repositioning of the application point of the brake lever and thus of the application axis Z, the elasticity of the application device 8 decreases.

[0045] By reducing the elasticity of the application device, the stroke reserve that must be maintained can be reduced, which reduces the angular coverage of the brake lever 10 to a pivot angle of the brake lever 10 of less than 90°, preferably less than 88°. In other words, the pivot lever only needs to be pivoted to a lesser extent than in the known prior art. This smaller pivoting changes further reduces the space required for the space that must be maintained. This space saving allows further redesign of the brake caliper. The brake caliper has, in a manner typical for this type of caliper, a lower opening for receiving and engaging over the brake disc 2. In addition, the brake caliper has an installation opening 23 on its brake caliper back for mounting the brake pads 6 in the brake carrier 4.

[0046] On both sides of the installation opening 23, caliper struts 24 are arranged, extending perpendicular to the plate plane of the brake disc 2. The radial thickness of these caliper struts 24 is preferably more than 13 mm, preferably 14-17 mm, in particular 15.5 mm + / - 1 mm. Such thick caliper struts are previously unknown and are made possible by the additional space gained by repositioning the brake application axis Z and the components required for application in the direction of the rotation axis.

[0047] Furthermore, due to the improved trigonometry of the arrangement and redesign of the brake lever 10 and the associated modified transmission ratio and increased mechanical rigidity of the brake application device 8, so-called progressive force lines can be reduced during power transmission, which has advantages, among other things, when this disc brake is used in a vehicle with ABS braking systems. Overall, the force applied by the brake cylinder 9 to the brake lever 10 of the disc brake according to the invention is more uniform.

[0048] It should be mentioned merely as an additional point that due to the increased mechanical rigidity of the brake application device 8, the thickness of the brake pads and / or the brake disc, as well as the brake disc diameter, can also be reduced. Furthermore, as already discussed above, the installation dimension of the brake is reduced.

[0049] In the radial direction, no further element, in particular no pad retaining bracket, protrudes radially from the caliper back at the level of the installation opening 24. In this variant, the brake pads are secured by the brake anchor plate 4, as explained in Fig. 5.

[0050] Fig. 5 shows a brake carrier 4 for use in the disc brake of Fig. 1-3 with corresponding pad shafts 26, 27. The pad shafts 26, 27 are each delimited laterally in the direction of rotation U and against the direction of rotation U by edge support surfaces 28a, 28b, 28c on brake carrier horns 29. The pad shafts 26, 27 have guide pockets 21 below the support surfaces 28a, in which the brake pads lie via edge projections, possibly with the aid of retaining springs. The guide pockets 21 are formed by a projection 30 projecting into the shaft, which in turn has an end support surface 28b. The outer contour of the brake pads essentially corresponds to the outer contour of the pad shaft.

[0051] A peripheral flank 28c is arranged between the support surfaces 28a and 28b. The peripheral flank 28b of the projection 30 is rectangular in shape, with the special feature that the axial extension of the flank 28b relative to the rotational axis A is greater than the radial extension of the support surface. Typically, one would attempt to achieve the most even force distribution possible over a large area with high applied forces.

[0052] However, this is not necessary in the present case, as cooperative braking results in a lower proportion of force acting on the support surfaces, particularly during braking at high speeds, and thus deformation tendencies occur to a lesser extent. On the other hand, this form of mounting advantageously saves space for the overall height of the brake and simultaneously allows for a comparatively delicate design of the brake carrier 4 with reduced space requirements and weight.

[0053] Figs. 6 and 7 show the brake carrier 4 with inserted brake pads 6, with ears 30 of the brake pad 6 resting in the molded pockets 21, so that the brake pad 6 is guided in the molded pockets. Advantageously, the brake pad carrier is supported by the brake pad horns at several points in the insertion direction of the pad shaft.

[0054] In the specific variant shown in Figs. 6 and 7, it is clearly visible that the brake carrier provides both peripheral support surfaces 28a and 28c and support surfaces 32a, 32b at an angle of 80-100°, preferably perpendicular, to these support surfaces 28a and 28c at the base of the respective pad carrier flange 29 or at the base of the projection 30. This double support allows for better force distribution when lateral forces are applied. Fig. 8 shows the installation of the disc brake within the rim contour.

[0055] REFERENCE SYMBOL

[0056] 1 disc brake

[0057] 2 brake discs

[0058] 3 brake caliper

[0059] 4 brake carriers

[0060] 5 lining shafts

[0061] 6 brake pads

[0062] 7 Recording room

[0063] 8 Clamping device

[0064] 9 brake cylinders

[0065] 10 brake levers

[0066] 11 eccentric

[0067] 12 Bridge

[0068] 13 saddle back

[0069] 14 Mounting opening

[0070] 15 locking plate

[0071] 16 Saddle head

[0072] 17 support surfaces

[0073] 18 rolling bearings

[0074] 19 Calotte

[0075] 20 actuating pistons

[0076] 21 guide pockets

[0077] 22 adjusting spindles

[0078] 23 Installation opening

[0079] 24 seat stays

[0080] 26 lining shaft

[0081] 27 Covering shaft

[0082] 28a-c Support surfaces

[0083] 29 brake carrier horns

[0084] 30 projection 50 rolling surface

[0085] 51 swivel track

[0086] 201 , 202 midpoints

[0087] A rotation size

[0088] U Direction of rotation

[0089] Z clamping axis

Claims

PATENT CLAIMS 1 . Disc brake (1 ) for a motor vehicle and / or bus with an electric A generator brake comprising a brake disc (2) with a rotational axis A and a set of brake pads (6) for applying the brake disc; wherein the disc brake (1) has a brake caliper (3) designed as a sliding caliper; wherein the disc brake (1) has an application device (8) for actuating the brake pads (6), which is arranged in a receiving space (7) of a brake caliper (3);wherein the disc brake (1) additionally has an actuating element for introducing force into the application device (8) with an actuating force, wherein the application device (8) has a brake lever (10) on which the actuating element acts with the actuating force and wherein the application device (8) acts on the brake pads (6) with an application force along an application axis Z, characterized in that the length of the brake lever (10) is selected such that the transmission ratio between the actuating force and the application force is between 1:15.60 - 1:16.45, preferably with a bridge stroke of 2.5 - 4 mm.; 2. Disc brake (1) according to claim 1, characterized in that the brake lever (10) has a calotte (19) for receiving an actuating piston (20) of the actuating element and in that the brake lever (10) has a curved rolling surface (50) along which the brake lever (10) rolls on a rolling bearing (18) in the receiving space (7) of the brake calliper (3) and in that the distance between the center point (202) of the curvature of the calotte (19) of the brake lever (10) and the center point (201) of the curvature of the rolling surface (50) of the brake lever (10) is between 78-82 mm.

3. Disc brake (1) according to claim 1 or 2, characterized in that the application device (8) has a rolling bearing (18) for pivoting Bearing of the brake lever (10), wherein the brake lever (10) and / or the rolling bearing (18) has means for limiting the pivoting angle, wherein the means are arranged such that the pivoting angle is limited to less than 90°, preferably less than 88°.

4. Disc brake (1) according to one of the preceding claims, characterized in that the brake calliper (3) has an installation opening (23) which has calliper struts (24) with axial extension on the edge, wherein the calliper struts (24) have a radial thickness of more than 13 mm, preferably 14-17 mm, particularly preferably 15.5 mm + / - 1 mm.

5. Disc brake (1) according to one of the preceding claims, characterized in that the brake calliper (3) has a calliper back (13), wherein no further element spanning the installation opening (23) in the axial direction protrudes radially from the calliper back (13).

6. Disc brake (1) according to one of the preceding claims, characterized in that the disc brake (1) has a brake carrier (4) with pad shafts (26, 27), wherein the pad shafts (26, 27) have guide pockets (21) on the edge side for holding and guiding brake pads.

7. Disc brake (1) according to one of the preceding claims, characterized in that the guide pockets (21) are formed by projections (30) which project into the lining shaft (26) at the edge opposite a lining shaft wall.

8. Disc brake (1) according to one of the preceding claims, characterized in that the application axis Z is arranged at a distance X parallel to the axis of rotation, wherein the distance X is between 2.5 - 8.5 mm.

9. Use of the disc brake (1 ) according to one of the preceding Claims in a motor vehicle and / or bus with an electric Generator brake, which carries out a cooperative braking simultaneously with the disc brake (1). Drive for applying a disc brake (1) according to one of the preceding claims, characterized in that a Pivoting of the brake lever (10) during the application process over the entire service life of the brake at a pivoting angle of less than 90°, preferably less than 88°.

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