Electromechanical frame brake

Abstract

The present invention relates generally to an electromechanical frame brake (10). The electromechanical frame brake (10) comprises a floating frame (18) composed of several parts and a brake piston (62) that is axially displaceable by means of a spindle drive (64), is mounted on a spindle (52) of the spindle drive (64), and is guided in a piston housing (24). The floating frame (18) has the piston housing (24), lateral struts (26), and an outer cross member (22) connected to the piston housing (24) via the struts (26). The cross member (22) carries an outer brake lining (40). The floating frame (18) is mounted in a brake carrier (20) of the frame brake (10) via axial linear guides (30) and is axially displaceable with respect to the brake carrier (20).The brake carrier (20) has a receptacle (86) with a cylindrical guide surface (88) for the piston receptacle housing (24) which is axially displaceable therein.

Description

[0001] The present invention relates to an electromechanical frame brake.

[0002] Electromechanical brakes with a floating frame have been known for some time.

[0003] The floating frame can be designed as a floating caliper, for example. However, floating caliper brakes have limited torsional rigidity due to the geometry of the caliper shape. Shear forces caused by the frictional forces that occur when the brake pads contact a brake disc rotor, which cause the brake components to twist relative to the brake carrier, are therefore only insufficiently compensated. As a result, the brake pads exhibit uneven wear. This leads to a varying ratio of shear forces to normal forces (along the axial direction) over the service life of the brake pads and the brake disc rotor.Due to the inconsistency of this force ratio, the guarantee of constant ventilation clearances (distances between the brake pads and the brake disc rotor, also called brake delivery path) over the service life of the brake pads and the brake disc rotor is prevented or at least adversely affected.

[0004] As an alternative to floating-caliper brakes, electromechanical brakes can also be designed as frame brakes. Frame brakes incorporate axially designed linear guides that can at least partially absorb and compensate for shear forces. This ensures that the force ratios of the shear forces to the normal forces over the service life of the brake pads and the brake disc rotor are maintained at a level that is less variable than with floating-caliper brakes. However, the axial linear guides are typically not positioned at the center of mass along the axial extent of the frame brake. This leads to tilting forces along the axial extent of the frame brake. Although these forces may be smaller than the comparable shear forces in floating-caliper brakes, they still cause distortion of frame brake components relative to a brake carrier.In other words, frame brakes have limited housing stiffness along their axial length, partly due to the generally higher weight caused by the linear guides. This, in turn, can cause uneven wear of the brake pads and thus inconsistent brake application paths over the service life of the brake pads and the brake disc rotor. Of course, the housing stiffness along the axial length of the frame brake can be increased by appropriately dimensioning the relevant components. However, this results in an increase in the required installation space and the weight of the frame brake, which ultimately leads to increased fuel or energy consumption of a vehicle with such a frame brake.

[0005] There is therefore a need to eliminate or at least mitigate the disadvantages of the state of the art. In particular, there is a need to provide an electromechanical brake that ensures a constant braking travel throughout the service life of the relevant components while simultaneously reducing weight and installation space compared to existing approaches.

[0006] The problem is solved by the subject matter of the independent patent claims. Advantageous embodiments are specified in the dependent patent claims and the following description, each of which, individually or in (sub)combination, may represent aspects of the disclosure. Some aspects are explained with regard to different variants. However, the features are reciprocally transferable.

[0007] According to one aspect, an electromechanical frame brake is provided. The electromechanical frame brake comprises a floating frame composed of several parts and a brake piston that is axially displaceable by means of a spindle drive, is seated on a spindle of the spindle drive, and is guided in a piston receiving housing. The floating frame has the piston receiving housing, lateral struts, and an external cross member connected to the piston receiving housing via the struts. The cross member carries an external brake pad. The floating frame is mounted in a floating manner relative to a brake carrier of the frame brake via axial linear guides and is axially displaceable relative to the brake carrier. The brake carrier has a receptacle with a guide surface for the piston receiving housing, which is received axially displaceably therein.

[0008] This provides a frame brake which, in addition to the lateral struts and axial linear guides, comprises a further guide based on the brake carrier holder, which has a guide surface for the piston receiving housing slidably received therein. This ensures an additional axial guide mechanism, by means of which the shear forces occurring when the frame brake is activated can be compensated in an improved manner compared to existing approaches. In addition, the brake carrier holder for the piston receiving housing slidably received therein can be arranged, in particular, closer to the center of mass along the axial longitudinal extent of the frame brake. As a result, the tipping forces caused by the weight distribution of the frame brake along the axial longitudinal extent can be reduced compared to existing approaches.This results in a frame brake with improved housing stiffness, both with regard to the shear forces that occur and with regard to the weight distribution along the axial length. This ensures that the force ratio of the shear forces that occur compared to the normal forces that occur when the frame brake is activated remains essentially constant over the service life of the brake pads and the brake disc rotor. As a result, the constancy of the actual brake application distance (i.e., the distance between the brake pads and the brake disc rotor) is improved over the service life of the brake pads and the brake disc rotor compared to existing approaches. In other words, uneven wear of the brake pads can be reduced.Thus, the actual brake application distance exhibits reduced deviations from the desired brake application distance, even over the service life of the brake pads and the brake disc rotor, compared to existing frame brakes. These advantages are achieved without requiring excessive material use or a (significant) increase in installation space. Therefore, a solution is created that does not cause any increase in the underlying fuel or energy consumption for a vehicle with such an electromechanical frame brake.

[0009] Preferably, the brake carrier represents a component to be locked on the vehicle side, by means of which the electromechanical frame brake can be mounted on a holder, for example a vehicle support structure.

[0010] The guide surface is preferably cylindrical. This ensures a symmetrical design with respect to its radial extension, allowing transverse forces perpendicular to the longitudinal direction of the frame brake to be absorbed particularly efficiently.

[0011] In some embodiments, the guide surface is designed to be at least partially concentric with a piston skirt surface of the brake piston. This can prevent the occurrence of eccentric forces upon activation of the brake piston. In other words, the axiality of the forces occurring is improved. The occurrence of shear forces relative to the longitudinal extension or tilting forces along the axial longitudinal extension of the frame brake is reduced or even prevented.

[0012] Optionally, the axial linear guides on the brake carrier are plain bearings. This ensures movement along the axial direction of the frame brake with low friction forces.

[0013] Preferably, the plain bearings are spaced equally radially from a center point of the cylindrical guide surface. This ensures a uniform distribution of forces between the plain bearings measured at the center point of the cylindrical guide surface. In other words, while two spaced-apart guide mechanisms are provided by the plain bearings and the cylindrical guide surface, they act as a quasi-unified guide mechanism. The arrangement is selected so that the relative arrangement itself does not cause any eccentric forces. As a result, the housing rigidity of the frame brake is further improved.

[0014] In some embodiments, the floating frame surrounds the brake carrier in a top view of the frame brake. Since the brake carrier ensures coupling to a vehicle structure, it represents the force application point with respect to the weight of the frame brake to be absorbed. The geometry specified here ensures that the floating frame, which represents the axial support structure, surrounds the brake carrier as the force application point. This can further improve the housing rigidity.

[0015] Optionally, the struts can be integrated into the cross member as a single piece. This reduces the number of required components as well as the number of material transitions and coupling points. This measure also leads to an improvement (increase) in the housing's rigidity.

[0016] Preferably, the piston housing is bolted to the struts at the front. This creates a detachable connection mechanism between the piston housing and the cross member, simplifying assembly or maintenance work, for example.

[0017] Optionally, the brake carrier has a radially outward-opening window through which an inside brake pad can be mounted and removed without dismantling the floating frame.

[0018] Alternatively or cumulatively, a radially outwardly open window is provided between the brake carrier and the cross member, through which the outer brake pad can be mounted and removed without dismantling the floating frame.

[0019] The radially outward-opening windows simplify maintenance work, especially for replacing brake pads, as this eliminates the need to disassemble the floating frame. In addition, the airflow cross-section for ventilating the brake pads can be increased through the windows, improving brake pad cooling.

[0020] Optionally, the piston housing has a base against which the spindle rests when the frame brake is applied. This absorbs the reaction forces that occur when the brake is applied due to the application forces. Starting from the base of the piston housing, the absorbed reaction forces can then be further transmitted, particularly to the cross member, to bring the outer brake pad into contact with the brake disc rotor.

[0021] In some embodiments, the piston receiving housing has a plurality of cylindrical, axially extending side walls by means of which axial guides for the spindle and / or the brake piston can be ensured.

[0022] The side walls and the base define a free internal volume enclosed by the piston housing, which defines the interior of the piston housing. The brake piston is at least partially accommodated in the interior of the piston housing.

[0023] Preferably, an axial spindle bearing with a bearing contact surface is arranged between the bottom of the piston housing and the spindle. The axial spindle bearing provides the possibility of simultaneously supporting the spindle and also allowing rotation of the spindle relative to the bottom of the piston housing. Furthermore, the spindle bearing can compensate for the occurrence of eccentric forces.

[0024] In some embodiments, the spindle transitions to its drive-side end via a circumferential shoulder into a drive shaft extension with a reduced cross-section. The shoulder has a convex section forming a ring on a spherical surface. The axial spindle bearing has a complementary contact section with the bearing contact surface to allow a tilting movement of the spindle relative to the piston receiving housing. The contact section of the axial spindle bearing is in particular complementary to the convex section of the spindle shoulder forming a ring on a spherical surface. The complementarity of the contact section of the axial spindle bearing and the section of the spindle shoulder forming the spherical surface ensures a centering mechanism by means of which even off-center force components of the reaction force are compensated.

[0025] In other words, the radial extension of the spindle varies along the axial direction, such that the spindle has a comparatively small radial extension at the end opposite the brake pad and a comparatively large radial extension at the end closest to the brake pad. Since the transition section of the spindle is located between these sections and represents a taper of the spindle with respect to the radial extension, the outer surface of the transition section can advantageously have the circumferential shoulder. This forms the convex section, forming a ring on a spherical surface, which is in contact with the axial spindle bearing.

[0026] The axial spindle bearing and the section of the spindle forming the spherical surface can preferably have rotational symmetry. This allows the axial spindle bearing and the section of the spindle to be designed identically on all sides with respect to the spindle's rotational axis.

[0027] Particularly preferably, the bearing contact surface of the axial spindle bearing is spherically shaped.

[0028] A spherical bearing contact surface is understood to mean, in particular, a bearing surface that has a spherical contour.

[0029] The spherical bearing contact surface is advantageously concave.

[0030] The curvature of the spherical bearing contact surface then creates a restoring force in the direction of the spindle's rotational axis. The spherical contour ensures that the restoring force increases with increasing distance between the force application point and the spindle's rotational axis. This means that with a suitable choice of force application point, larger restoring forces are generated, forcing the spindle into an orientation along the rotational axis.

[0031] Optionally, the spherical bearing contact surface of the axial spindle bearing has a first radius of curvature, and the complementary contact surface of the transition section has a second radius of curvature. Advantageously, the first and second radius of curvature are different. This results in line contact (circular line) between the complementary contact surface and the bearing contact surface, particularly when no force is applied. When the clamping force is generated and the reaction forces occur as a result, surface contact develops between the contact surfaces as the force increases due to elastic flattening of the surfaces. Thus, an osculation exists between the contact surfaces. This ensures that the centering effect becomes stronger with increasing force.

[0032] In particular, the axial spindle bearing can be an axial roller bearing. The axial spindle bearing ensures the spindle's ability to rotate relative to the piston housing without increasing frictional torque.

[0033] The axial spindle bearing can have a planar contact surface on a bearing ring, particularly on the side opposite the spherical bearing contact surface, with which it axially supports itself against the adjacent rolling elements. Thus, the axial spindle bearing, with its spherical bearing contact surface and the opposite, planar contact surface, ensures the most uniform contact possible between the rolling elements and the bearing ring, because the rotational degrees of freedom perpendicular to the spindle's rotational axis are not lost, thus compensating for micro- and macroscopic angular misalignments or off-center forces.

[0034] In a particularly preferred embodiment, the axial spindle bearing is supported on the bottom of the piston housing. The piston housing is oriented such that the open end is arranged in the direction of the brake disc rotor and the inside brake pad, i.e. on the brake pad side, and such that the bottom of the piston housing is arranged opposite to this in the axial direction. This means that the generated clamping forces act in the axial direction along the open end of the piston housing, while the subsequently occurring reaction forces act towards the bottom. Because the axial spindle bearing is supported on the bottom of the piston housing, the axial spindle bearing is thus arranged between the bottom and the spindle along the direction of action of the reaction forces. This enables the axial spindle bearing to absorb the reaction forces particularly well.

[0035] Particularly preferably, the base of the piston housing has a raised plateau that extends axially from the base toward the brake disc rotor. This allows the axial spindle bearing to be positioned further inside the brake piston. This shortens the axial length of the piston housing of the frame brake and reduces the required axial space.

[0036] Preferably, a bearing disk is arranged axially between the base of the piston receiving housing and the rolling elements of the axial spindle bearing. This bearing disk is pressed into the piston receiving housing by frictional engagement and / or positive engagement to prevent rotation. Due to its geometry, the piston receiving housing is a more complex component than the bearing disk. The bearing disk can protect the base of the piston receiving housing from damage caused by the axial spindle bearing (if it were in direct contact with the base), which could generally be caused by a worn axial spindle bearing and under the influence of reaction forces. If necessary, only the bearing disk or the entire axial spindle bearing needs to be replaced, but not necessarily the piston receiving housing.

[0037] In particular, the bearing disc can have two opposing planar contact surfaces, one of which is in contact with the base of the piston housing and one of which is in contact with the rolling elements. This results in the additional advantage that the manufacturing effort required to ensure the quality of the contact surface of the base of the piston housing can be reduced.

[0038] The rolling elements of the axial spindle bearing then roll on the one hand on the planar contact surface of the bearing ring at the brake pad-side end of the axial spindle bearing and on the other hand on a planar contact surface of the bearing disc, which also forms a bearing ring.

[0039] A bearing, such as a ball or plain bearing, is provided between the drive shaft extension with its reduced cross-section of the spindle and the piston housing. Axial displacement of the spindle relative to the piston housing is prevented by a fastening element, such as a snap ring. The snap ring can be arranged, for example, in a radial groove of the piston housing, extending from the bottom of the piston housing opposite the brake disc rotor. The snap ring can also be multi-layered.

[0040] The brake piston is preferably designed as a spindle nut with a spindle thread formed on its inner side. The spindle drive is configured to ensure linear displacement of the brake piston relative to the spindle. By means of the play drive, the brake piston acting as a spindle nut can be moved in the axial direction. The brake piston can thus apply an application force to at least one brake pad (the inside brake pad) of the brake, so that a frictional connection with the brake disc rotor can be generated. This means that the spindle can be rotated about the axis of rotation and that this rotation causes a translational movement of the brake piston along the axial direction in order to provide application forces for at least one brake pad (the inside brake pad). As a result of the application forces generated, oppositely oriented reaction forces arise which generally have off-center force components.These force components can generally cause shear forces, which are, however, absorbed and compensated by the several guide mechanisms, i.e. the lateral struts, the axial linear guides and the mount with the cylindrical guide surface.

[0041] The electromechanical frame brake described here features a rotary lock between the piston housing and the brake piston, which is accommodated within it for linear displacement. The rotary lock allows linear displacement of the brake piston but prevents rotation of the brake piston relative to the piston housing.

[0042] The rotary lock preferably comprises an elongated hole with which a rotation-locking element engages.

[0043] An anti-rotation device is optionally provided between the piston housing and the brake carrier of the frame brake. For example, a positive fit can be provided between the piston housing and the brake carrier, preventing rotation of the piston housing relative to the brake carrier.

[0044] The positive locking device provided to prevent rotation of the piston housing can have a tongue and groove connection, a tangential pin connection or an elongated hole with which an anti-rotation element engages.

[0045] An optional axially expanding seal is provided radially between the brake piston and the brake carrier. This protects, in particular, the internal guide surfaces of the brake carrier and the piston housing for the brake piston from contamination (e.g., brake debris). This extends the service life of the spindle and the support for the axially displaceable piston housing.

[0046] Preferably, a circumferential bellows seal is arranged radially outward between the brake carrier and the piston housing. The bellows seal prevents external contaminants from entering the housing for the axially displaceable piston housing. This extends the service life of the housing's guide mechanism.

[0047] In some embodiments, the brake carrier has a return element. Preferably, the receptacle of the brake carrier has such a return element. The return element is configured to return the piston receiving housing to an initial position when the frame brake is not subjected to force, in particular along the axial longitudinal extent of the frame brake. When the application force is exerted, the piston receiving housing is displaced along the axial direction by the resulting reaction forces, specifically in the direction opposite to the brake disc rotor. In other words, the distance between the piston receiving housing and the brake disc rotor increases. As a result, the outer brake pad comes into contact with the brake disc rotor. When the application of the application force is discontinued, no further reaction forces occur.In this case, the return element ensures that the piston housing, and thus also the cross member coupled to the piston housing and the outer brake pad, are returned to their initial position (the non-force-loaded position), i.e., toward the brake disc rotor. This ensures that the outer brake pad is free from contact with the brake disc rotor.

[0048] Preferably, the brake carrier mount has a groove in which the return element is arranged. This groove allows installation space to be saved along the axial extent of the frame brake. Furthermore, this arrangement also allows the return element to function as an additional sealing element, thus preventing the ingress of contaminants.

[0049] Optionally, the return element has an annular body. The return element is arranged radially outwardly of a housing surface of the piston housing. This ensures circular symmetry with respect to the return force exerted by the return element. The axiality of the frame brake is also increased.

[0050] The return element preferably comprises an elastic material, in particular an elastomer. The return element can then adapt particularly well to the installation space located between the brake carrier and the piston receiving housing. In addition, the durability of the return element is increased. The return element preferably deforms when force is applied to the frame brake, i.e. when the frame brake is actuated, and in doing so stores deformation energy. The return element is operatively connected to the brake carrier and the piston receiving housing in such a way that when the brake is released, i.e. when the force is removed from the frame brake, the stored deformation energy is released and the piston receiving housing and thus also the cross member coupled to the piston receiving housing and the outer brake pad are moved back into their starting position, as already described.

[0051] Alternatively, the return element can also be designed as a metal spring, in particular as a circumferential metal spring.

[0052] In some embodiments, the bellows seal can be omitted. In this case, the return element can additionally ensure the sealing functionality of the bellows seal. This advantageously results in the frame brake having fewer components. Furthermore, manufacturing is less complex.

[0053] Optionally, the brake piston has a front wall on the brake pad side, which presses against an inner brake pad of the frame brake when the brake is applied. The front wall can have a circular-shaped end face. This shifts the point of application of the application force acting on the brake pad radially outward, allowing for a more even application of the brake pad across the entire surface. Thus, the force applied to the brake pad is improved.

[0054] The spindle drive preferably has a recirculating ball screw. In a recirculating ball screw, balls transfer the force between the spindle and the brake piston, which acts as the spindle nut. The rolling motion of the balls reduces friction and wear. A recirculating ball screw is non-self-locking. This means that, due to inherent elasticity, the brake piston automatically returns to the retracted position even when it is no longer actively driven into the extended position by a motor, such as an electric motor.

[0055] Preferably, rotation of the spindle is ensured by means of an electric motor and a reduction gear of the frame brake, which meshes with the drive shaft extension of the spindle.

[0056] Optionally, the piston housing, in which the spindle is mounted, features a positive, sliding connection with the gearbox used to drive the spindle. This ensures centering of the drive gearbox relative to the piston housing.

[0057] Preferably, the positive connection between the piston receiving housing and the gear of the drive has a shaft-hub connection with a multi-spline toothing or a tongue-and-groove connection.

[0058] The electromechanical frame brake can in particular be designed to serve as a vehicle brake with brake pads and a brake disc rotor.

[0059] According to a further aspect, a vehicle with an electromechanical frame brake as described above is also provided.

[0060] Optionally, the vehicle may include, in particular, a motor vehicle, i.e., a road vehicle. Alternatively, the vehicle may also include other vehicle types, such as two-wheelers, motorcycles, or similar.

[0061] In general, a vehicle is understood here as a device configured for transporting objects, cargo, or people between different destinations. Examples of vehicles include land-based vehicles such as motor vehicles, electric vehicles, hybrid vehicles, or similar. Preferably, vehicles in this context can be considered road-based vehicles, such as cars, trucks, buses, or the like.

[0062] All features explained with regard to the various aspects can be combined individually or in (sub-)combination with other aspects.

[0063] The disclosure as well as further advantageous embodiments and developments thereof are described and explained in more detail below with reference to the examples shown in the drawings. They show: - Fig. 1 a simplified schematic isometric representation of the electromechanical frame brake according to an embodiment of the invention, - Fig. 2 a simplified schematic front view of the electromechanical frame brake according to the invention, - Fig. 3 a simplified schematic plan view of the electromechanical frame brake according to the invention, - Fig. 4 a simplified schematic bottom view of the electromechanical frame brake according to the invention, - Fig. 5 to Fig. 8 simplified schematic sectional views along the section lines AA, BB, CC and DD of the electromechanical frame brake according to the invention as in Fig. 2 indexed, - Fig. 9 a further simplified schematic representation of the electromechanical frame brake according to the invention to illustrate a change of the brake pads.

[0064] The following detailed description, taken in conjunction with the accompanying drawings, in which like numerals refer to like elements, is intended to describe various embodiments of the disclosed subject matter and is not intended to be the only embodiments. Each embodiment described in this disclosure is merely exemplary or illustrative and should not be construed as preferred or advantageous over other embodiments.

[0065] All features disclosed below with respect to the embodiments and / or the accompanying figures may be combined alone or in any sub-combination with features of the aspects of the present disclosure, including features of preferred embodiments, provided that the resulting combination of features is meaningful to a person skilled in the art.

[0066] Fig. 1 shows a simplified schematic isometric representation of the electromechanical frame brake 10 according to an embodiment of the invention.

[0067] The electromechanical frame brake 10 comprises a brake actuator unit 14 and a drive unit 16 along the axial extension direction 12. The brake actuator unit 14 comprises a support structure designed as a floating frame 18, which is displaceable along the axial extension direction 12.

[0068] The electromechanical frame brake 10 has a brake carrier 20 by means of which the frame brake 10 can be mounted on a support, for example a vehicle support structure.

[0069] Axially outward relative to the brake carrier 20, the floating frame 18 has a cross member 22 to which an outside brake pad of the frame brake 10 is at least indirectly coupled.

[0070] In addition, the floating frame 18 has a piston receiving housing 24 for a brake piston guided therein. The piston receiving housing 24 is arranged opposite the cross member 22, starting from the brake carrier 20.

[0071] The cross member 22 is coupled to the piston housing 24 via radially outer lateral struts 26, into which corresponding locking screws 28 engage.

[0072] The lateral struts 26 are formed integrally with the cross member 22. The integral design of the lateral struts 26 with the cross member 22 eliminates the need for assembly mechanisms and material transitions. This increases the housing rigidity of the frame brake 10, and in particular of the floating frame 18.

[0073] The lateral struts 26 extend along the axial extension direction 12, starting from the cross member 22 and extending beyond the brake carrier 20. This leads to an additional increase in the housing rigidity of the floating frame 18 of the frame brake 10.

[0074] By increasing the housing stiffness, the shear forces occurring when the frame brake 10 is activated can be compensated and dissipated better than before.

[0075] The cross member 22 is additionally coupled to the brake carrier 20 by means of axial linear guides 30, which have plain bearings 31, into which corresponding locking screws 32 engage. The axial linear guides 30 extend along the axial extension direction 12.

[0076] The axial linear guides 30 ensure axial displaceability of the floating frame 18 relative to the brake carrier 20. Since the piston receiving housing 24 is rigidly coupled to the cross member 22 of the floating frame 18, the piston receiving housing 24 is also displaceable relative to the brake carrier 20 by the axial linear guides 30.

[0077] Fig. 2 shows a simplified schematic front view of the electromechanical frame brake 10 according to the invention.

[0078] It can be seen here that the axial linear guides 30 have equal radial distances 36 with respect to the rotational axis 34 of the brake actuator unit 14 of the frame brake 10 (which, ideally, corresponds to compensated shear and tilting forces, also to the rotational axis of the underlying brake disc rotor). In other words, the axial linear guides 30 are arranged symmetrically with respect to the rotational axis 34 of the frame brake 10. This prevents the axial linear guides 30 from causing eccentric forces.

[0079] The brake carrier 20 comprises corresponding coupling structures 37 by means of which the frame brake 10 can be mounted, for example on a vehicle supporting structure.

[0080] In this view, the section lines AA, BB, CC and DD of the sectional views are also shown according to the Fig. 5 to 8 indicated.

[0081] Fig. 3 shows a simplified schematic plan view of the electromechanical frame brake 10 according to the invention and Fig. 4 shows a simplified schematic bottom view of the electromechanical frame brake 10 according to the invention.

[0082] In the area of ​​the brake carrier 20, a receiving space 38 for the brake disc rotor is provided.

[0083] An outer brake pad 40 is mounted on the cross member 22. An inner brake pad 42 is arranged along the axial extension direction 12 in the opposite direction, starting from the receiving space 38, so that the brake disc rotor can come into contact with the outer brake pad 40 and the inner brake pad 42 from opposite directions during operation. The brake disc rotor is thus enclosed by the two brake pads 40, 42 along the axial extension direction 12.

[0084] While the inside brake pad 42 is generally actively movable in the direction of the brake disc rotor by the brake piston of the brake actuator unit 14, contact between the outside brake pad 40 and the brake disc rotor is ensured by the displaceability of the floating frame 18 as such.

[0085] It can also be seen that the brake carrier 20 forms a radially outwardly open window 44 for the inside brake pad 42.

[0086] In addition, a further radially outwardly open window 46 is formed between the brake carrier 20 and the cross member 22 for the outside brake pad 40.

[0087] The outer brake pad 40 and the inner brake pad 42 can be removed from or inserted into the frame brake 10 through the windows 44, 46, for example for assembly purposes or when replacing during maintenance work. In this context, Fig. 9 shows a further simplified schematic representation of the electromechanical frame brake 10 according to the invention, illustrating a replacement of the brake pads 40, 42, which can be passed through the windows 44, 46. This enables a replacement of the brake pads 40, 42, which advantageously does not require disassembly of other parts of the frame brake 10.

[0088] In the representations of the Fig. 3 and Fig. 4 it can also be seen that the axial linear guides 30 have axially flexible guide seals 48, by means of which the linear guides 30 can be protected from contamination.

[0089] In addition, the frame brake 10 includes a circumferential bellows seal 50 in the area of ​​the piston housing 24, which extends between the brake carrier 20 and the piston housing 24. Since the brake carrier 20 provides guidance for the piston housing 24, as explained in detail below, this guidance can be protected from contamination by the bellows seal 50.

[0090] Fig. 5 to Fig. 8 show simplified schematic sectional views along the section lines AA, BB, CC and DD of the electromechanical frame brake 10 according to the invention, as in Fig. 2 indexed.

[0091] The rotation axis 34 of the brake actuator unit 14 of the frame brake 10 corresponds, in the ideal case of compensated shear and tilting forces, also to the rotation axis of the underlying brake disc rotor and the center axis of the overall housing of the frame brake 10 (essentially defined by the brake carrier 20).

[0092] During operation, the inside brake pad 42 is actively subjected to a clamping force Fz in the direction of the brake disc rotor by the brake actuator unit 14.

[0093] The axially displaceable floating frame 18 ensures that the brake pad 40 on the outside in the axial direction is also subjected to the application force Fz. The application force Fz is distributed essentially equally between the inside brake pad 42 and the outside brake pad 40. Thus, as a result of the provided contact pressure, a frictional engagement with the brake disc rotor arranged in the receiving space 38, which is used to decelerate or immobilize a vehicle, can be ensured for both brake pads 40, 42.

[0094] The frame brake 10 further includes an electromechanical actuation unit serving as a drive unit 16, which is used to generate the application force Fz together with the brake actuator unit 14. Relative to the brake actuator unit 14, the drive unit 16 is arranged opposite to the brake disc rotor along the axial extension direction 12. The drive unit 16 comprises at least one electric motor, a reduction gear, and a parking brake mechanism.

[0095] The components of the drive unit 16 are coupled to the piston housing 24. Their weight is thus absorbed by the brake carrier 20. The housing components of the frame brake 10 are generally designed as a skeletal frame made of metal or fiber-reinforced plastic. The drive unit 16 forms a self-contained, separately mountable subassembly.

[0096] The brake actuator unit 14 comprises a spindle 52 with a drive shaft extension 54, a brake pad-side shaft portion 56, and a transition portion having a shoulder 58. The shoulder 58 is arranged along the rotational axis 34 of the spindle 52 between the drive shaft extension 54 and the shaft portion 56. The diameter of the drive shaft extension 54 of the brake actuator unit 14 is smaller along the radial direction than the diameter of the shaft portion 56 along this direction. Accordingly, the spindle 52 tapers in terms of its diameter in the region of the transition portion.

[0097] The brake actuator unit 14 further comprises a spindle nut 60, which in this case is designed as a brake piston 62. The spindle drive 64 of the brake actuator unit 14 is designed as a self-locking ball screw. This means that the spindle drive 64 comprises a spindle thread 66 in which balls 68 are arranged and roll. The spindle 52 and the spindle nut 60 have corresponding raceway parts that together form the spindle thread 66. The balls 68 can enable a translational movement of the spindle nut 60 along the rotation axis 34 relative to the spindle 52 along the ball raceways 70 of the spindle thread 66. For this purpose, the ball raceways 70 are formed at least partially in the shaft section 56 of the spindle 52 and the spindle nut 60.

[0098] The diameter of the ball raceways 70 corresponds to the diameter of the balls 68, taking into account manufacturing tolerances and required gap dimensions.

[0099] The rotation of the spindle 52 is ensured by the electric motor of the drive unit 16, which engages the drive shaft extension 54 of the spindle 52 via the reduction gear. The pitches of the spindle drive 64, in particular of the ball races 70, then result in the rotation of the spindle 52 causing a translational movement of the spindle nut 60. The spindle nut 60, designed as a brake piston 62, transmits this movement to the brake pads 40, 42. The generated clamping force Fz is proportional to the torque exerted on the drive shaft extension 54 by the drive unit 16.

[0100] The inside brake pad 42 is actively acted upon by the clamping force Fz generated in this way, starting from the brake piston 62.

[0101] The brake actuator unit 14 further includes the piston housing 24, which has a radially inner inner side 72 and a bottom 74. The open end of the piston housing 24 is arranged along the rotation axis 34 on the brake pad side. This means that the bottom 74 is arranged at the end of the piston housing 24 opposite the brake disc rotor. The bottom 74 has a through hole 76 for the drive shaft extension 54 of the spindle 52, which is held therein by means of a radial bearing 78 (sliding bearing).

[0102] The axial displacement of the spindle 52 relative to the piston housing 24 is prevented by a fastening means, for example a snap ring 80. The snap ring 80 is arranged on the side of the base 74 of the piston housing 24 facing away from the shaft portion 56 of the spindle 52.

[0103] The piston housing 24 is coupled to the drive unit 16 by means of a positive connection 82 such that the reduction gear is centered relative to the piston housing 24. The positive connection 82 can, for example, comprise a shaft-hub connection with a splined toothing or a tongue-and-groove connection.

[0104] The radially inner inner side 72 and the base 74 define an interior space 84 of the piston receiving housing 24, in which at least the spindle 52 and the spindle nut 60 or the brake piston 62 are at least partially arranged. Due to the linear displaceability of the brake piston 62, designed as a spindle nut 60, this component can also be arranged at least partially outside the interior space 84.

[0105] The piston receiving housing 24 enables the brake actuator unit 14 to be designed as a separate subassembly.

[0106] The brake carrier 20 comprises a receptacle 86 with a cylindrical guide surface 88. The cylindrical guide surface 88 of the brake carrier 20 is configured to correspond to a radially outer housing surface 90 of the piston receiving housing 24. The cylindrical guide surface 88 of the brake carrier 20 is also configured concentrically with a piston surface 91 of the brake piston 62, which is configured as a spindle nut 60. The centers of the cylindrical guide surface 88 and the piston surface 91 of the brake piston 62 coincide with the rotation axis 34 in the ideal case of compensated transverse forces.

[0107] The cylindrical guide surface 88 of the brake carrier 20 is delimited by a base portion 92 of the brake carrier 20. The cylindrical guide surface 88 and the base portion 92 define the receptacle 86, in which the piston receiving housing 24 is mounted for axial displacement. The bellows seal 50 extends circumferentially between the brake carrier 20 and the piston receiving housing 24 and delimits the receptacle 86 along the axial extension direction 12 in the direction opposite to the base portion 92 of the brake carrier 20.

[0108] An anti-rotation device 94 is formed between the brake carrier 20 and the piston receiving housing 24, by means of which rotation of the piston receiving housing 24 relative to the brake carrier 20 is prevented.

[0109] In addition, a rotary lock 96 is formed between the piston receiving housing 24 and the spindle nut 60, by means of which rotation of the spindle nut 60 relative to the piston receiving housing 24 is prevented.

[0110] The piston housing 24, with the spindle drive 64 accommodated therein, the spindle nut 60 designed as a brake piston 62, and the spindle 52, is thus mounted radially and axially as a subassembly in the receptacle 86 of the brake carrier 20, ensuring axial displacement. Relative rotation is only permitted for the spindle 52 and the balls 68 of the spindle drive 64, and otherwise prevented for the other components.

[0111] As a result of the generated application force Fz, a reaction force Fr opposite to the application force Fz occurs along the rotation axis 34. Due to the elastic expansion of the components of the frame brake 10, an angular offset can generally occur between the rotation axis of the brake disc rotor and the cylinder axis of the frame brake 10, so that the reaction force Fr has off-center force components. These off-center force components can lead to instability of the components of the brake actuator unit 14 along the radial direction, particularly if the core diameter of the spindle drive 64 is smaller than the outer diameter of a bearing intended to absorb the reaction force Fr.

[0112] Therefore, the brake actuator unit 14 in this case comprises a rotationally symmetrical axial spindle bearing 98 designed as an axial bearing with a bearing ring 100 having a spherical bearing contact surface 102 arranged on the brake pad side. The axial spindle bearing 98 is in contact with the shoulder 58 of the spindle 52, which has a convex section 104 forming a ring on a spherical surface. The spherical bearing contact surface 102 is concave and complementary to the section 104.

[0113] The bearing ring 100 further has a planar contact surface 106 which is arranged along the rotation axis 34 opposite to the spherical bearing contact surface 102.

[0114] Furthermore, the brake actuator unit 14 has rolling elements 108 which are in contact with the planar contact surface 106.

[0115] The piston receiving housing 24 comprises a high plateau 110 extending axially from the bottom 74 in the direction of the brake disc rotor.

[0116] Between the axial spindle bearing 98 and the bottom 74 of the piston housing 24, a bearing disk 112 is additionally arranged, which has opposing planar contact surfaces along the rotation axis 34 and is pressed into the piston housing 24 in a rotationally secure manner by frictional and / or positive engagement. One of the contact surfaces of the bearing disk 112 is in contact with the raised plateau 110 of the piston housing 24. The rolling elements 108 roll on the other of the two contact surfaces of the bearing disk 112. The raised plateau 110 shortens the axially required length of the piston housing 24, thereby saving installation space along the axial extension direction 12.

[0117] Thus, the occurring reaction force Fr is transmitted from the shaft section 56 of the spindle 52 via the shoulder 58 to the spherical bearing contact surface 102 of the axial spindle bearing 98, and from there is absorbed by the bottom 74 of the piston receiving housing 24 via the rolling elements 108 and the bearing disk 112.

[0118] The reaction force Fr is transmitted to the cross member 22 via the lateral struts 26, so that the outside brake pad 40 can be moved in the direction of the brake carrier 20 in order to ensure contact of the outside brake pad 40 with the brake disc rotor.

[0119] The displaceability of the cross member 22 relative to the brake carrier 20 is ensured by the axial linear guides 30. Since these guides are spaced 36 from the center point 114 of the cylindrical guide surface 88, which coincides with the rotation axis 34, these guide mechanisms act jointly (quasi-uniformly). Thus, shear forces occurring when the frame brake 10 is activated can be compensated for better than before, since previous frame brakes do not have the additional guide mechanism of the mount 86.

[0120] Since the mount is provided by the brake carrier 20 itself, it is also located close to the center of mass of the frame brake 10. The guide mechanisms are advantageously arranged on both sides of the center of mass of the frame brake. The guide mechanism, which is provided by the axial linear guides 30, is arranged axially on the outside relative to the brake carrier. In contrast, the guide mechanism of the mount 86 of the brake carrier is arranged axially on the inside. This allows for better compensation of tilting forces that can occur due to the mass distribution of the components of the frame brake 10 along the axial extension direction 12. As a result, the housing rigidity of the frame brake 10 is increased. This ensures the previously explained advantages with regard to service life, maintaining the desired brake application distance, and reducing the fuel consumption of a vehicle with the frame brake 10.

[0121] In order to protect the spindle drive 64 in particular, an axially expanding seal 116 extends between the spindle nut 60 and the brake carrier 20.

[0122] Fig. 5 shows two embodiments 118A and 118B of the receptacle 86 of the brake carrier 20 at the bottom left and bottom right. The position of the embodiments 118A, 118B is shown in the main image of the Fig. 5 indexed.

[0123] In general, the receptacle 86 of the brake carrier 20 has the cylindrical guide surface 88, in which the housing surface 90 of the piston receiving housing 24 is axially displaceably mounted. In embodiment 118A, it can be seen that a gap 120 is formed between the guide surface 88 and the housing surface 90. The brake carrier 20 comprises a groove 122 located radially outward relative to the housing surface 90 of the piston receiving housing, in which a return element 124 is arranged.

[0124] In this case, the return element 124 is made of an elastically deformable elastomer and shaped as an annular body. However, it is also conceivable that the return element 124 is designed as a metal spring. In this case, the return element 124 thus encloses the housing surface 90 of the piston housing 24.

[0125] With the help of the return element 124, the axially displaceable piston receiving housing 24 can be moved back to an initial position when no force is applied, i.e., along the axial direction toward the brake disc rotor. Since the outer brake pad 40 is indirectly coupled to the piston receiving housing 24 via the cross member 22, the outer brake pad 40 is then moved away from the brake disc rotor—beyond the rotor—so that the distance between the outer brake pad 40 and the brake disc rotor increases. Consequently, the return element 124 can ensure a defined initial position of the outer brake pad 40, which is released by the return element 124.

[0126] In addition, the return element 124 also ensures centering of the piston receiving housing 24.

[0127] In embodiment 118B, the bellows seal 50 is omitted. In this case, the return element 124 also ensures a sealing function, which in embodiment 118A is ensured by the bellows seal 50. This means that the return element 124 can, in particular, protect the receptacle 86 from contamination with respect to the guidance of the housing surface 90 of the piston receiving housing 24 within the guide surface 88 of the brake carrier 20. In addition, the spindle drive 64 is then also protected from contamination.

[0128] In both embodiments 118A and 118B, the cutting edge of the groove 122, which is further away from the brake disc rotor (when producing the groove, two cutting edges are created by piercing a turning tool or turning tool), can each be provided with a chamfer 130, with which the rollback effect, ie the storage and release of the deformation energy of the elastic ring body, especially when using an elastomer, and thus the return of the piston receiving housing is supported.

Claims

[1] Electromechanical frame brake (10) with a floating frame (18) composed of several parts, a brake piston (62) which is axially displaceable by means of a spindle drive (64) and is seated on a spindle (52) of the spindle drive (64) and guided in a piston receiving housing (24), wherein the floating frame (18) has the piston receiving housing (24), lateral struts (26) and an external cross member (22) which is connected to the piston receiving housing (24) via the struts (26) and which carries an external brake pad (40), wherein the floating frame (18) is mounted in a floating manner relative to a brake carrier (20) of the frame brake (10) via axial linear guides (30) and is axially displaceable relative to the brake carrier (20), and the brake carrier (20) has a receptacle (86) with a guide surface (88) for the piston receiving housing (24) which is received axially displaceably therein. [2] Electromechanical frame brake (10) according to claim 1, characterized bythat the guide surface (88) is formed at least in regions concentrically to a piston jacket surface (91) of the brake piston (62) and / or that the guide surface is formed cylindrically. [3] Electromechanical frame brake (10) according to claim 1 or 2, characterized by that the axial linear guides (30) are plain bearings (31) on the brake carrier (20). [4] Electromechanical frame brake (10) according to claim 3, characterized by that the plain bearings (31) have equal radial distances from a center point of the guide surface (88). [5] Electromechanical frame brake (10) according to one of the preceding claims, characterized by that in a plan view of the frame brake (10) the floating frame (18) surrounds the brake carrier (20). [6] Electromechanical frame brake (10) according to one of the preceding claims, characterized by that the struts (26) merge integrally into the cross member (22). [7] Electromechanical frame brake (10) according to claim 6, characterized by that the piston housing (24) is screwed to the struts on the front side. [8] Electromechanical frame brake (10) according to one of the preceding claims, characterized by that the brake carrier (20) has a radially outwardly open window (44) through which an inside brake pad (42) can be mounted and removed without dismantling the floating frame (18), and / or between the brake carrier (20) and the cross member (22) there is a radially outwardly open window (46) through which the outside brake pad (40) can be mounted and removed without dismantling the floating frame (18). [9] Electromechanical frame brake (10) according to one of the preceding claims, characterized by that the piston receiving housing (24) has a base (74) on which the spindle (52) is supported when the frame brake (10) is actuated. [10] Electromechanical frame brake (10) according to claim 9, characterized by that an axial spindle bearing (98) with a bearing contact surface (102) is arranged between the bottom (74) of the piston receiving housing (24) and the spindle (52). [11] Electromechanical frame brake (10) according to claim 10, characterized by that the spindle (52) merges at its drive-side end via a circumferential shoulder (58) into a drive shaft extension (54) with a reduced cross-section, wherein the shoulder (58) has a convex section (104) forming a ring on a spherical surface and the axial spindle bearing (98) has a complementary contact section with the bearing contact surface (102) in order to allow a tilting movement of the spindle (52) relative to the piston receiving housing (24). [12] Electromechanical frame brake (10) according to one of the preceding claims, characterized bythat the brake piston (62) is shaped as a spindle nut (60) in that a spindle thread (66) is formed on its inner side (72). [13] Electromechanical frame brake (10) according to one of the preceding claims, characterized by that an axially expanding seal (116) is provided radially between the brake piston (62) and the brake carrier (20). [14] Electromechanical frame brake (10) according to one of the preceding claims, characterized by that a circumferential bellows seal (50) is arranged radially outwardly between the brake carrier (20) and the piston receiving housing (24). [15] Electromechanical frame brake (10) according to one of the preceding claims, characterized by that the brake carrier (20), in particular the receptacle (86) of the brake carrier (20), has a return element (124) which is designed to return the piston receiving housing (24) to an initial position in a non-force-loaded state of the frame brake. [16] Electromechanical frame brake (10) according to claim 15, characterized by that the receptacle (86) of the brake carrier (20) has a groove (122) in which the return element (124) is arranged. [17] Electromechanical frame brake (10) according to claim 15 or 16, characterized by that the return element (124) has an annular body, wherein the return element is arranged radially outwardly of a housing surface (90) of the piston receiving housing (24). [18] Electromechanical frame brake (10) according to one of claims 15 to 17, characterized by that the return element (124) comprises an elastic material, in particular an elastomer.

Images