Braking system for a motor vehicle and motor vehicle

Abstract

The invention relates to a braking device (14) for a motor vehicle, comprising a friction disc (20) which is arranged axially between a first counter-rotating disc (42) and a second counter-rotating disc (16) of the braking device (14), wherein the friction disc (20) has internal teeth which engage in a counter-tooth (46) provided on a connecting element (90) which is rotationally fixed to an output shaft (24) and is designed as external teeth; an annular cup-shaped return spring (85) is arranged on an inner circumferential region of the connecting element (90), which partially surrounds the connecting element (90) and is connected to the connecting element (90) via an interference fit and is in operative contact with the friction disc (20); the connecting element (90) has a machined surface (FL) on which the return spring (85) bears in an interference fit;and an axial extent of the machined surface (FL) is greater than an overlap length over which the return spring (85) overlaps the connecting element (90).

Description

[0001] The invention relates to a braking device for a motor vehicle. The invention also relates to a motor vehicle with at least one such braking device.

[0002] DE 10 2019 118 503 A1 discloses a brake device for a wheel hub drive arrangement as known, comprising a housing section for arranging the brake device on the wheel hub drive arrangement.

[0003] The object of the present invention is to provide a braking device for a motor vehicle and a motor vehicle with such a braking device, in such a way that a particularly advantageous resetting of the braking device can be realized.

[0004] This problem is solved by a braking device with the features of claim 1 and by a motor vehicle with the features of claim 4. Advantageous embodiments with expedient further developments of the invention are specified in the remaining claims.

[0005] A first aspect of the invention relates to a braking device, also simply referred to as a brake or friction brake, for a motor vehicle, also simply referred to as a vehicle. This means that the motor vehicle, preferably designed as a motor vehicle, in particular as a passenger car, has the braking device in its fully manufactured state. In particular, the braking device is designed as a friction disc brake device, which is also simply referred to as a disc brake device or disc brake. As will be explained in more detail below, the braking device is a friction brake device, and thus a friction brake. For example, the motor vehicle, in its fully manufactured state, has at least one vehicle wheel, also simply referred to as a wheel, which is a ground contact element.The ground contact element allows the vehicle to be supported or supported downwards against the ground in its vertical direction. When the vehicle is driven along the ground while supported downwards in its vertical direction by the ground contact element, the ground contact element rolls along the ground, particularly directly. The vehicle wheel, for example, is rotatable about a wheel axis relative to a reference element of the vehicle, particularly the braking system, so that the vehicle wheel rotates about the wheel axis relative to the reference element, particularly when it rolls along the ground, particularly directly.For example, the braking device can be used to brake the vehicle wheel with respect to a rotation about the wheel axis and relative to the reference element, i.e., to slow it down and thus at least reduce its speed, thereby braking the vehicle as a whole. In particular, the braking device is or constitutes a service brake of the vehicle.

[0006] The braking device has a friction disc which is arranged axially between a first counter-running disc and a second counter-running disc of the braking device.

[0007] It is conceivable that the braking system includes a housing in which, for example, the friction disc and the counter-rotating disc can each be at least partially arranged. This housing is also simply referred to as the housing. Thus, the vehicle wheel can rotate around the wheel axis relative to the housing.

[0008] For example, the friction disc is rotatable about an axis of rotation relative to the counter-rotating discs and preferably also relative to the housing assembly. For example, the friction disc is torque-transmitting, and in particular rotationally fixed, coupled or coupling to the vehicle wheel, whereby, for example, when the vehicle wheel rotates about the wheel's axis of rotation and relative to the reference element, the friction disc can rotate with the vehicle wheel and thus about the axis of rotation relative to the counter-rotating discs and, in particular, relative to the housing assembly. By actuating the braking device, in particular hydraulically, the friction disc can, for example, be brought into, in particular, direct, mutual frictional contact with the counter-rotating discs, whereby the friction disc can be braked, i.e., slowed down and thus at least decelerated, during a rotation about the axis of rotation and relative to the counter-rotating discs.This means, for example, that because the friction disc is torque-transmitting, and in particular rotationally fixed, and can be coupled to the vehicle wheel, the vehicle wheel can be braked for rotation about the wheel axis and relative to the reference element, thus making the vehicle as a whole brakeable. By actuating the braking device, particularly hydraulically, braking can be effected, whereby the friction disc can be braked with respect to its rotation about the axis of rotation and relative to the counter-rotating discs and preferably relative to the housing assembly, thus making the vehicle wheel, for example, brakeable with respect to its rotation about the wheel axis and relative to the reference element and, in particular, relative to the housing assembly. This allows the vehicle as a whole to be braked.

[0009] For example, the friction disc has a first friction surface and a second friction surface. The first counter-rotating disc has, for example, a third friction surface, which is, for example, axially oriented towards the first friction surface. The second counter-rotating disc has, for example, a fourth friction surface, which is, for example, axially oriented towards the second friction surface. By actuating the braking device, particularly hydraulically, the first friction surface can be brought into, in particular, direct, frictional contact with the third friction surface, and the second friction surface can be brought into, in particular, direct, frictional contact with the fourth friction surface, so that when the friction disc rotates about the axis of rotation relative to the counter-rotating discs, friction is generated between the first friction surface and the third friction surface, and between the second friction surface and the fourth friction surface.This friction allows the friction disc, and therefore in particular the vehicle wheel, to be braked, i.e., slowed down.

[0010] For example, the respective counter-rotating disc is a brake disc element. For example, the friction disc is a brake disc element.

[0011] The friction disc has internal teeth that engage with mating teeth designed as external teeth. The mating teeth are provided on a connecting element that is rotationally fixed to an output shaft. In particular, the mating teeth are teeth on the connecting element. The connecting element is specifically designed separately from the friction disc. Because the internal teeth engage with the mating teeth (external teeth), the friction disc is, for example, permanently and rotationally fixed to the connecting element. The connecting element is, in particular, permanently and rotationally fixed to the output shaft, which is also simply referred to as the shaft. It is conceivable that the connecting element is designed separately from the output shaft and, in particular, permanently and rotationally fixed to the output shaft.For example, at least part of the output shaft is rotatable around the axis of rotation relative to the housing assembly, so that, for example, at least the part of the output shaft with the friction disc can rotate around the axis of rotation relative to the housing assembly and relative to the counter-rotating discs. Thus, by braking the friction disc, the output shaft can be braked, i.e., slowed down, as it rotates around the axis of rotation relative to the housing assembly.

[0012] The aforementioned part of the output shaft is, for example, a first shaft section of the output shaft. The output shaft has, for example, a joint, also referred to as a universal joint, by means of which a second shaft section of the output shaft is articulated to the first shaft section of the output shaft. The output shaft is, for example, torque-transmitting, and in particular rotationally fixed, and can be coupled to or is coupled to the vehicle wheel, such that the vehicle wheel can be driven by means of the output shaft and is thereby rotatable about the wheel's axis of rotation relative to the reference element and, in particular, relative to the housing assembly.Since the friction disc is coupled or can be coupled to the output shaft via the internal teeth, the external teeth and the connecting element in a torque-transmitting manner, in particular in a rotationally fixed manner, the output shaft can be braked with respect to a rotation of the output shaft about the axis of rotation and relative to the housing assembly by braking the friction disc as described above, whereby this braking of the output shaft, by virtue of the fact that the output shaft can be connected or is connected to the vehicle wheel in a torque-transmitting manner, in particular in a rotationally fixed manner, brakes the vehicle wheel with respect to a rotation about the wheel axis of rotation and relative to the reference element, thereby enabling the vehicle as a whole to be braked.

[0013] The connecting element is or forms, for example, a gear carrier supporting the mating teeth, which can be designed, for example, at least essentially in a ring shape and thus as a gear carrier ring.

[0014] The braking device, whose axial direction coincides with the axis of rotation, has a return spring, which is formed separately from the connecting element and is arranged on an inner circumferential region of the connecting element. The return spring is annular and thus designed as an annular cup spring. The return spring partially surrounds the connecting element. This means, in particular, that the annular cup spring surrounds at least an axially extending length of the connecting element in the circumferential direction around the axis of rotation of the braking device, at least partially, in particular at least predominantly and thus at least more than halfway, or even completely, i.e., over 360 degrees.The circumferential direction of the braking device, whose radial direction is perpendicular to the axial direction of the braking device, runs around the axis of rotation and in an imaginary plane that is perpendicular to the axial direction of the braking device and thus perpendicular to the axis of rotation. When the circumferential direction is mentioned before and after, it refers to the circumferential direction of the braking device unless otherwise specified. When the axial direction is mentioned before and after, it refers to the axial direction of the braking device unless otherwise specified. When the radial direction is mentioned before and after, it refers to the radial direction of the braking device unless otherwise specified. The term "radial" refers to the radial direction, and the term "axial" refers to the axial direction.

[0015] The return spring is connected to the connecting element via an interference fit. Furthermore, the return spring is in operative contact with the friction disc, particularly axially, and especially resiliently. This means that the return spring is supported at least indirectly, and in particular directly, by the friction disc, preferably in the axial direction. For example, by actuating the braking device, particularly hydraulically, the return spring is at least partially elastically deformable or deformed, thereby providing a force, particularly acting in the axial direction, which is also referred to as spring force or restoring force.For example, the friction disc can be displaced or moved, particularly axially, relative to the housing and relative to the counter-rotating discs by actuating the brake device, especially hydraulically, and thereby, for example, from a starting position to an actuated position. In the actuated position, the return spring is, for example, more elastically deformed than in the starting position, whereby the return spring provides the restoring force.By means of the restoring force, acting particularly in the axial direction, the friction disc can be reset and thus, for example, moved from the actuated position back to the initial position or in the direction of the initial position, particularly relative to the counter-rotating discs and especially relative to the housing assembly, thereby enabling a particularly space-saving and thus particularly advantageous reset of the friction disc and thus of the braking device. In particular, the spring force acts, especially axially, at least indirectly, and especially directly, from the restoring spring on the friction disc.

[0016] Furthermore, according to the invention, the connecting element has a machined surface which, for example, points radially outwards or, preferably, inwards. For example, the machined surface is cylindrical and thus formed in the form of a right circular cylinder, whose central axis, also referred to as the cylinder axis, with respect to which the circular cylinder is, for example, rotationally symmetrical, coincides, for example, with the axis of rotation, which is why the machined surface can be described as a coaxial circular cylinder surface. The return spring rests against the machined surface, forming an interference fit by means of which the return spring is connected to the connecting element, particularly directly, and especially in a radial direction from the outside inwards or from the inside outwards.

[0017] Furthermore, according to the invention, the axial extent of the machined surface is greater than the axial overlap length over which the return spring overlaps the connecting element and, in particular, bears directly against the machined surface. This means that the machined surface has a first sub-surface and a second sub-surface axially and directly adjoining the first sub-surface, each sub-surface having a respective axial length, and the sum of these axial lengths constitutes the axial extent of the machined surface.The return spring rests, in particular directly, against the first partial surface, so that the first partial surface is overlapped by the return spring in a radial direction outwards or inwards, whereby the return spring does not rest against the second partial surface, so that the second partial surface connects to the first partial surface and to the return spring in an axial direction, in particular directly.

[0018] In particular, the aforementioned length range of the connecting element is overlapped in the radial direction outwards by the return spring, that is, by a partial area of ​​the return spring encompassing the length range.

[0019] Because the return spring, designed as a ring cup spring, is connected to the connecting element by means of an interference fit and thus frictionally, this frictional connection between the return spring and the connecting element acts as an adjusting device for the return spring. For this purpose, it is specifically designed that the frictional connection, i.e., the interference fit, allows axial movement, particularly translational movement, of the return spring relative to the connecting element, so that a particularly advantageous adjustment is possible. Wear on the brake linings forming the friction surfaces, also referred to as brake pad wear, increases the respective axial clearance between the respective counter-rotating disc and the friction disc, in particular between the first and third friction surfaces and between the second and fourth friction surfaces.This allows the friction disc to be moved axially further towards the first counter-rotating disc when the braking device, also simply referred to as a brake, is actuated under high pressure, particularly hydraulically. The friction disc can thereby axially displace the return spring, causing the return spring to be moved axially relative to the connecting element. This axial displacement of the return spring relative to the connecting element is permitted by the press fit. In this way, wear on at least the first friction surface and / or the third friction surface, which is axially adjacent to the first friction surface, can be compensated for, thus ensuring advantageous actuation of the braking device even over a particularly long operating or service life.

[0020] For example, the respective friction surface is at least essentially ring-shaped.

[0021] In an advantageous embodiment of the invention, the braking device comprises the aforementioned housing assembly in which the friction disc and the counter-rotating discs are each at least partially arranged. The first counter-rotating disc is fixed to the housing assembly in a rotationally fixed and axially fixed manner and is therefore neither rotatable about the axis of rotation relative to the housing assembly nor axially displaceable relative to the housing assembly. The second counter-rotating disc is fixed to the housing assembly in a rotationally fixed manner and is therefore not rotatable about the axis of rotation relative to the housing assembly. Furthermore, the second counter-rotating disc is axially displaceable relative to the housing assembly, relative to the friction disc, and relative to the first counter-rotating disc.

[0022] Furthermore, it is preferably provided that the friction disc is axially displaceable relative to the housing assembly and relative to the counter-rotating discs. In particular, the friction disc is rotatable about the axis of rotation relative to the housing assembly and relative to the counter-rotating discs.

[0023] Another embodiment is characterized by the fact that the ring cup spring extends radially outside the external teeth and in an axial direction along a portion of the connecting element, where this portion of the connecting element is, for example, the aforementioned length range. This allows for a particularly advantageous return of the brake mechanism and a particularly advantageous wear compensation in a space-saving manner.

[0024] A second aspect of the invention relates to a motor vehicle, also referred to simply as a vehicle, and preferably designed as a motor car, in particular as a passenger car, which has at least one braking device according to the first aspect of the invention. Advantages and advantageous embodiments of the first aspect of the invention are to be regarded as advantages and advantageous embodiments of the second aspect of the invention and vice versa.

[0025] For example, the braking device is integrated into an axle drive unit, particularly an electric axle drive unit, with the braking device being integrated, for instance, into a housing of the axle drive unit. Furthermore, it is conceivable that the braking device is integrated into an axle component such as the axle drive unit, or that the braking device is integrated, for example, into a differential or into a chassis component such as an axle carrier.

[0026] Further advantages, features, and details of the invention will become apparent from the following description of a preferred embodiment and from the drawing. The features and combinations of features mentioned above in the description, as well as those mentioned below in the figure description and / or shown in the figures alone, can be used not only in the combinations specified, but also in other combinations or individually, without departing from the scope of the invention.

[0027] The drawing shows in: Fig. 1. A schematic sectional view of an electric axle drive device of a motor vehicle, wherein a friction disc brake device, also simply referred to as a brake device, is integrated into the electric axle drive device; Fig. 2. Partially a schematic longitudinal section view of the friction disc brake device; Fig. 3. Partially shown is another schematic longitudinal section view of the friction disc brake device; Fig. 4. Partially a schematic longitudinal section view of the axle drive unit; Fig. 5. Partially shown is another schematic longitudinal section view of the axle drive device; Fig. 6. Partially shown is another schematic longitudinal section view of the axle drive unit; and Fig. 7. Partially shown is another schematic longitudinal section view of the axle drive device;

[0028] In the figures, identical or functionally equivalent elements are provided with the same reference symbols.

[0029] Fig. Figure 1 shows a partial schematic longitudinal sectional view of an electric axle drive unit 10 of a motor vehicle, which is also simply referred to as the vehicle and can be driven, in particular purely electrically, by means of the electric axle drive unit 10. For example, the electric axle drive unit 10, also referred to as the electric drive module, has a vehicle axle of the motor vehicle. For example, the motor vehicle has exactly two vehicle axles, namely the aforementioned vehicle axle as the first vehicle axle and a second vehicle axle. The vehicle axles are arranged consecutively in the longitudinal direction of the motor vehicle and thus one behind the other. Each vehicle axle has exactly two vehicle wheels. The respective vehicle wheels of each vehicle axle are arranged on opposite sides of the motor vehicle in the transverse direction of the motor vehicle.The vehicle wheels of the motor vehicle are ground contact elements of the motor vehicle. Since, for example, the electric axle drive unit 10 comprises the first vehicle axle, the axle drive unit 10 also comprises the vehicle wheels of the first vehicle axle. For example, the vehicle wheels of the first vehicle axle can be driven electrically by means of the axle drive unit 10, and thus the motor vehicle can be driven electrically.

[0030] The axle drive unit 10 comprises a housing 12 and at least one electric machine (not visible in the figures), which is at least partially arranged in the housing 12. The electric machine has a stator and a rotor, which can be driven by means of the stator and is thus rotatable about a machine axis relative to the stator. The electric machine can provide drive torques via the rotor for, in particular, purely electric, driving of the vehicle wheels of the first vehicle axle. Furthermore, it is conceivable that at least or exactly one of the vehicle wheels of the first vehicle axle can be driven, in particular purely electric, by means of the electric machine and thus by means of the axle drive unit 10. When the vehicle wheels are mentioned below, unless otherwise specified, this refers to the vehicle wheels of the first vehicle axle.When the vehicle wheel is mentioned below, unless otherwise specified, this refers to the vehicle wheel that can be driven by means of the axle drive unit 10, that is, by means of the electric machine of the axle drive unit 10. Thus, the vehicle wheel can be driven by the rotor and is therefore rotatable about a wheel axis relative to the housing 12.

[0031] For example, the axle drive unit 10 has a gearbox, which can be at least partially arranged in the housing 12. The preceding and following descriptions of the vehicle wheel can readily be applied to the vehicle wheels of the first vehicle axle and vice versa. For example, the vehicle wheel can be driven by the rotor and thus by the electric machine via the gearbox. As will be explained in more detail below, a braking device 14 is integrated into the axle drive unit 10, by means of which braking can be effected, i.e., carried out. During or through braking, the vehicle wheel can be braked with respect to a rotation about the wheel axis and relative to the housing 12, i.e., its rotation can be stopped.In other words, when braking is carried out by means of the braking device 14, the vehicle wheel is thereby braked with respect to its rotation about the wheel axis and relative to the housing 12, i.e., slowed down, or at least decelerated. The braking device 14 is a friction disc brake device, as will be explained in more detail below. The braking device 14 has a first brake disc element 16 with a first friction surface 18. Furthermore, the braking device 14 has a second brake disc element 20 with a second friction surface 22. The axle drive device 10 has a shaft 24, for example, designed as a driveshaft, wherein at least a part of the shaft 24 is rotatable about an axis of rotation 26 relative to the housing 12 and also relative to the brake disc element 16, and thus relative to the direction 18.The brake disc element 20 of the brake assembly 14, whose axial direction coincides with the axis of rotation 26 and is illustrated by a double arrow 28, also has a third friction surface 30. The brake assembly 14, whose radial direction is perpendicular to the axial direction of the brake assembly 14 and thus perpendicular to the axis of rotation 26 and is illustrated by a double arrow 32, also has a piston 34, which is also referred to as the actuating piston. When the axial direction is mentioned before and below, this refers, unless otherwise specified, to the axial direction of the brake assembly 14.When the radial direction is mentioned before and below, unless otherwise specified, this refers to the radial direction of the braking device 14, whose circumferential direction is around the axial direction and thus around the axis of rotation 26, and lies in an imaginary plane perpendicular to the axial direction and thus perpendicular to the axis of rotation 26. The circumferential direction of the braking device 14 is illustrated by a double arrow 36. The term "axial" refers to the axial direction, and the term "radial" refers to the radial direction.

[0032] The aforementioned part of the shaft 26, which is rotatable about the axis of rotation 26 relative to the housing 12 and relative to the brake disc element 16, is designated 38 and is, for example, a first shaft section of the drive shaft. The drive shaft, which is, for example, a constant velocity joint, has a joint 40 through which the first shaft section (section 38) is articulated to a second shaft section of the drive shaft (not shown in the figures) and, in particular, is coupled for torque transmission.The brake disc element 20, and thus the friction surfaces 22 and 30, are connected, in particular permanently, to torque-transmitting and rotationally fixed, at least to the part of the shaft 24, so that at least the part 38 of the shaft 24 and the brake disc element 20, and thus the friction surfaces 22 and 30, are rotatable about the axis of rotation 26 relative to the housing 12 and also relative to the brake disc element 16 and thus relative to the friction surface 18. For example, the second shaft section is coupled, or can be coupled, to the vehicle wheel in a torque-transmitting and rotationally fixed manner. Thus, the second shaft section can rotate with the vehicle wheel about the wheel's axis of rotation relative to the housing 12.

[0033] At least part 38 of the shaft 24 and thus the brake disc element 20 are, especially when the vehicle wheel is rotated around the wheel axis relative to the housing 12, rotatable with the vehicle wheel and thus rotatable around the axis 26 relative to the housing 12 and also relative to the brake disc element 16.

[0034] The electric machine can drive the shaft 24 and the brake disc element 20 via its rotor, and in particular by means of the respective drive torque, thereby rotating at least part 38 of the shaft 24 and the brake disc element 20 about the axis of rotation 26 relative to the housing 12. As will be explained in more detail below, the braking device 14 can brake the shaft 24 and, via this, the vehicle wheel with respect to their respective rotations relative to the housing 12.

[0035] At the in Fig. In the embodiment shown in Figure 1, the brake device 14 has a third brake disc element 42 with a fourth friction surface 44. The brake disc elements 16 and 42, and thus the friction surfaces 18 and 44, are at least indirectly rotationally fixed to the housing 12 and are therefore not rotatable about the axis of rotation 26 relative to the housing 12. The brake disc element 16 is axially displaceable relative to the housing 12 and preferably also relative to the brake disc element 20 and, most preferably, also relative to the brake disc element 42. The brake disc element 20 is, for example, axially displaceable relative to the housing 12 and preferably also relative to the brake disc element 16 and, more preferably, relative to the brake disc element 42. For this purpose, a toothed connection 46 is provided, which is also referred to as a drive tooth.The brake disc element 20 is connected to the part 38 by means of the toothing 46 in a torque-transmitting manner, and in particular in a rotationally fixed manner, and is thus rotatable with the part 38 about the axis of rotation 26 relative to the housing 12. However, the toothing 46 allows axial displacements of the brake disc element 20 relative to the housing 12. For example, the piston 34 is also axially movable, and in particular displaceable, relative to the housing 12 and, for example, relative to the brake disc element 16, and preferably relative to the brake disc element 20 and relative to the brake disc element 42. The brake disc element 42 is rotationally fixed to the housing 12 and is therefore not rotatable about the axis of rotation 26 relative to the housing 12. Furthermore, it is preferably provided that the brake disc element 20 is axially fixed to the housing 12 and is therefore not axially movable relative to the housing 12.The brake disc element 16 is preferably connected to the housing 12 in a rotationally fixed manner and is therefore not rotatable about the axis of rotation 26 relative to the housing 12. For this purpose, for example, a second toothed section 48 is provided, which is referred to, for example, as a second drive tooth. Thus, for example, the brake disc element 16 is connected to the housing 12 in a rotationally fixed manner by means of the toothed section 48, whereby the toothed section 48, however, allows axial displacements and displacements relative to the housing 12, i.e., translational movements of the brake disc element 16.

[0036] In this case, the piston 34 is designed as an annular piston. The piston 34 can be actuated, particularly directly, with hydraulic fluid and thus hydraulically actuated. For this purpose, a hydraulic channel 50, through which the hydraulic fluid flows, runs within the housing 12. Furthermore, an actuation chamber 52, also referred to as the working chamber, is provided, which is partially and directly bounded by the housing 12 and partially and directly by the piston 34. The hydraulic channel 50 opens into the actuation chamber 52. This allows the hydraulic fluid flowing through the hydraulic channel 50 to be introduced into the actuation chamber 52, thereby enabling the piston 34 to be actuated, particularly directly, with the hydraulic fluid.By hydraulically actuating the piston 34, the piston 34 is axially movable, i.e., in an axial direction relative to the housing 12 and, for example, also relative to the brake disc elements 16, 20 and 42, i.e., displaceable.

[0037] The brake assembly 14 also includes a transmission element 54, which is separate from the piston 34 and separate from the brake disc elements 16, 20, and 42, and which is also referred to as an actuating element. By means of the hydraulic actuation of the piston 34 described above, the transmission element 54 can be actuated by means of the piston 34 and is thereby axially movable and relative to the housing 12, i.e., displaceable. This means that the transmission element 54 is axially movable, i.e., displaceable, relative to the housing 12 and, for example, also relative to the brake disc element 20 and, in particular, relative to the brake disc element 42.By actuating the transmission element 54, the first brake disc element 16 can be actuated by means of the transmission element 54 and thereby moved axially and relative to the housing 12 and preferably also relative to the brake disc element 20 and preferably relative to the brake disc element 42, i.e., displaced. For this purpose, the transmission element 54 is, for example, at least indirectly axially rigidly connected to the brake disc element 16, so that, for example, axially directed relative movements between the first brake disc element 16 and the transmission element 54 are prevented.It can be seen that by hydraulically actuating the piston 34, the transmission element 54 and, via the transmission element 54, the first brake disc element 16 can be actuated. This allows the friction surfaces 18 and 22, and in this case also the friction surfaces 30 and 44, to be brought into direct, mutual frictional contact, thus braking the part 38 and therefore the vehicle wheel relative to the housing 12. For example, the friction surface 18 is first moved axially towards the friction surface 22 and brought into direct frictional contact with it. Furthermore, the friction surface 30 is moved axially towards the friction surface 44 and brought into direct frictional contact with it.

[0038] It can be seen that the friction surfaces 18 and 22 are axially oriented towards each other, and the friction surfaces 30 and 44 are axially oriented towards each other.

[0039] A cooling structure 56 is arranged on the rear side R of the brake disc element 16, which faces axially away from the friction surface 18 and also from the friction surface 22. The transmission element 54, for example, is connected to the brake disc element 16 via this cooling structure, in particular such that axial relative movements between the transmission element 54 and the first brake disc element 16 are prevented. The cooling structure 56 has at least one or more cooling channels, which are also referred to as first cooling channels. A preferably liquid coolant can flow through each first cooling channel, thereby advantageously cooling the brake disc element 16 and, for example, also the transmission element 54.

[0040] At the in Fig. In the embodiment shown in Figure 1, a second cooling structure 58 is provided on a wide rear side R2 of the brake disc element 42, which faces axially away from both the friction surface 44 and the friction surface 30. The second cooling structure 58 has, for example, at least one or more second cooling channels. The respective second cooling channel can be permeated by the coolant, for example, thereby advantageously cooling the third brake disc element 42.

[0041] Shaft 24 is, for example, an output shaft of the axle drive unit 10. It is conceivable that the rotor and / or shaft 24 are arranged coaxially with the vehicle wheel, so that, for example, the machine axis of rotation and / or the axis of rotation 26 coincide with the wheel axis of rotation. In particular, the axle drive unit 10 can drive the vehicle wheel at its end face via shaft 24, which functions as a drive shaft.

[0042] The housing 12 comprises a first housing part 60 and a second housing part 62, wherein the housing part 62 is, for example, a first cover of the housing 12. The first cover is also referred to as a side cover. Considering only the housing part 60, the housing part 60 has a housing opening 64, which is at least partially closed by the housing part 62. The housing parts 60 and 62 are formed separately from one another and are connected to each other at least indirectly, and in particular directly, in such a way that relative movements between the housing parts 60 and 62 are prevented. In particular, the side cover is arranged on an end face, in particular an axial face, of the housing part 60. The shaft 24 is supported in the side cover, in this case by means of at least one bearing 66 designed as a rolling bearing, which in this case is a ball bearing.The shaft 24, designed as an output shaft, therefore runs centered on the side cover, in particular such that at least part 38 runs centered on the side cover. In particular, at least part 38 is rotatably mounted in and on the housing part 62 (side cover) by means of the bearing 66, that is, rotatably mounted about the axis of rotation 26 relative to the housing 12.

[0043] The brake disc element 20 has a pad carrier disc, also referred to simply as a carrier disc, which is, for example, a base body of the brake disc element 20. The carrier disc is centered on the toothing 46 and is thus axially displaceable relative to the shaft 24 and the housing 12, but torque-transmitting, and in particular rotationally fixed, to the part 38, in particular the shaft 24. The carrier disc is provided, for example, with a first brake pad and a second brake pad, wherein, for example, the first brake pad forms the friction surface 22 and the second brake pad the friction surface 30. It can be seen that the friction surfaces 22 and 30 are arranged on axially opposite sides of the carrier disc, with the friction surfaces 22 and 30 pointing away from each other axially.

[0044] It is conceivable that the friction surface 44 is an outer surface of the side cover (housing part 62). Thus, it would be conceivable that the brake disc element 42 is formed as a single unit with the side cover. In the case of the Fig. In the embodiment shown in Figure 1, however, the brake disc element 42 is designed separately from the side cover and connected to the side cover (housing part 62), in particular in such a way that relative movements between the side cover and the brake disc element 42 are prevented. Since, for example, the cooling structure 58 is provided here, the brake disc element 42 is a cooled, in particular liquid-cooled, brake disc.

[0045] For example, the respective cooling structure 56, 58 is formed by or designed as a respective cooling plate. Since the aforementioned, preferably liquid, coolant can flow through the respective cooling channel and thus through the respective cooling plate, the cooling plate is a cooled, in particular liquid-cooled, cooling plate. The coolant can advantageously absorb heat via the respective cooling structure 56, 58, which is generated during the aforementioned braking process, also referred to as braking, by the friction surfaces 18, 22, 30 and 44 rubbing against each other.

[0046] The brake disc element 16 is a friction disc that is connected to the housing 12, particularly to the side cover, in a torque-transmitting and, in particular, rotationally fixed manner, but is axially displaceable relative to the housing 12 and thus relative to the side cover. In particular, the brake disc element 16 is centered relative to the side cover by means of the toothing 48.

[0047] The side cover forms, that is, directly delimits, a receiving space 68, also referred to as an interior. For example, the receiving space 68 is annular. The brake disc elements 16 and 22, and preferably also the brake disc element 42, are arranged in the receiving space 68, which is formed, that is, delimited, by the side cover. The side cover at least partially closes the housing opening 64 and thus an interior space 70 of the housing 12, also referred to as a housing chamber, to the outside, i.e., towards an environment 72 of the axle drive unit 10. The interior space 70 is formed, that is, directly delimited, by the housing part 60, with, for example, the transmission and the electric motor each being at least partially arranged in the interior space 70.

[0048] The side cover is an intermediate cover arranged axially between housing part 60 and a third housing part 74 of the housing 12. Housing part 74 is separate from housing parts 60 and 62 and is connected to them at least indirectly. Housing part 74 is connected to the side cover at least indirectly, in particular such that relative movements between the side cover and housing part 74 are prevented. Specifically, housing parts 60, 62, and 74 are connected to each other in pairs such that relative movements between them are prevented when considered as a pair. Housing part 74 is also referred to as the end cover. Looking at the side cover alone, it has an opening 76 through which the receiving chamber 68 is open to the outside and thus to the surroundings 72.The end cap at least partially closes off the cover opening 76 and thus the receiving chamber 68 to the outside and therefore to the surroundings 72. It is evident that the piston 34 is at least partially located within the end cap. In this case, the piston 34 is at least partially radially arranged within the end cap. Furthermore, the piston 34 is arranged to overlap the end cap axially, at least partially. It is also evident that the hydraulic channel 50 runs within the end cap, and that the actuation chamber 52 is directly bounded partly by the piston 34 and partly by the end cap.

[0049] It is also evident that the end cap is arranged radially overlapping with the brake disc elements 20, 16 and 42, so that the brake disc elements 16, 20 and 42 are at least partially covered axially to the environment 72 by the end cap.

[0050] By hydraulically actuating the piston 34, the hydraulically actuated piston 34 presses axially against the transmission element 54 and thus, via this element, indirectly against the brake disc element 16. The transmission element 54 is frustoconical in shape to achieve advantageous force transmission. Preferably, the transmission element 54 is made of stainless steel or ceramic to prevent excessive heat transfer from the transmission element 54 to the piston 34. The aforementioned stainless steel and ceramic exhibit lower thermal conductivity compared to conventional steel or aluminum.

[0051] By bringing the friction surfaces 18 and 22 and the friction surfaces 30 and 44 into direct, friction-fit contact, a braking torque can be generated, thereby braking the shaft 24 and, via this, the vehicle wheel relative to the housing 12. This process generates braking heat.

[0052] To avoid excessively high temperatures of piston 34 and the hydraulic fluid, it is particularly well shown that Fig. 2 and Fig. As can be seen in Figure 3, the transmission element 54 has a first groove 78 and the piston 34 has a second groove 80. An intermediate element 82 is provided, formed separately from the transmission element 54 and the piston 34 and arranged in the grooves 78 and 80, by means of which the transmission element 54 and the piston 34 are connected. The intermediate element 82 is a thermally separating compensating element by means of which the piston 34 can be thermally decoupled from the transmission element 54 and thus from the friction surfaces 18, 22, 30 and 44, which is particularly advantageous. In the embodiment shown in the figures, the intermediate element 82 is formed from an elastomer and is designed as an O-ring, which makes the intermediate element 82 elastically deformable, in particular with rubber elasticity.For example, the inner diameter of the piston 34 at the location of the groove 80 is larger than the outer diameter of the transmission element 54 at that location by a radial offset that is the maximum possible due to tolerances. To prevent excessive vibrations between the piston 34 and the transmission element 54, the intermediate element 82 bridges a radial gap located at that point between the transmission element 54 and the piston 34. Furthermore, the intermediate element 82 allows the piston 34 and the transmission element 54 to be joined together in a pre-assembly step.

[0053] Out of Fig. 2 and Fig. Figure 3 clearly shows that the transmission element 54 has a projection 84 extending axially from a base region G of the transmission element 54 and away from the brake disc elements 16 and 20, in the outer circumferential surface M1 of which the first groove 78 is formed. The piston 34 has an inner circumferential surface M2 facing radially towards the outer circumferential surface M1, which surrounds the outer circumferential surface M1 and the first groove 78 in the circumferential direction. The second groove 80 is formed in the inner circumferential surface M2.

[0054] Furthermore, it is provided that a chamfer F of the inner circumferential surface M2, which expands axially towards the base area G, adjoins the second groove 80 at an end E of the piston 34 which is axially directed towards the base area G.

[0055] Fig. Figure 2 shows an unactuated state of piston 34. Fig. Figure 3 shows the piston 34 in an actuated state, which is hydraulically actuated in this state. This means that the Fig. Figure 3 shows the actuated state of piston 34 resulting from the previously described hydraulic actuation of piston 34. The piston 34 can be moved from the actuated state to the unactuated state, for example, by ending the hydraulic actuation of piston 34.

[0056] Out of Fig. 2 and Fig. Figure 3 shows that, by hydraulically actuating the piston 34, the piston 34 is axially displaceable and thus movable relative to the housing 12 and relative to the transmission element 54, and in the direction of the friction surfaces 18 and 22, under elastic deformation of the intermediate element 82. This allows an end face SF of the piston 34 to be displaceable and thus movable in direct contact with a corresponding support surface AF of the transmission element 54. This means that, in the actuated state of the piston 34, the end face SF rests directly against the corresponding end surface AF, enabling a particularly advantageous force transmission between the piston 34 and the transmission element 54. In the actuated state of the piston 34, the intermediate element 82 is elastically deformed to a greater extent than in the unactuated state of the piston 34.When the hydraulic actuation of the piston 34 is terminated, this allows at least partial elastic relaxation of the intermediate element 82, which is also referred to as an expansion effect. In other words, when the hydraulic actuation of the piston 34 is terminated to release the actuated state of the piston 34, the intermediate element 82, which was initially elastically deformed in the actuated state of the piston 34, can at least partially relax and thus spring back. This allows the piston 34, and therefore its end face SF, to be axially displaced and thus moved away from the transmission element 54 and the support surface AF. As a result, in the unactuated state of the piston 34, the end face SF is completely separated from the support surface AF.Preferably, it is provided that in the unactuated state of the piston 34 the piston 34 is completely spaced away from the transmission element 54 which is formed separately from the piston 34, thereby avoiding an undesirable, excessive transfer of heat from the transmission element 54 to the piston 34.

[0057] The piston 34 and the transmission element 54 are preferably made of a metallic material. Thus, when the brake device 14 is actuated, the piston 34 presses with its axial end face SF against the support surface AF and thus against the transmission element 54, creating direct metallic contact between the piston 34 and the transmission element 54. After the brake is released, i.e., after the hydraulic actuation of the piston 34 has ceased, the intermediate element 82, which is elastically deformed at least or exclusively axially when the piston 34 is actuated, ensures that the piston 34 and the transmission element 54 move axially away from each other and thus separate at least slightly, such that the end face SF and the support surface AF are pushed axially away from each other and thus, in particular, completely separated from each other.This prevents excessive heat transfer from the hot transmission element 54 to the piston 34.

[0058] The brake assembly 14 has a spring element 85. The spring element 85 is designed as a solid body and thus as a mechanical spring element, i.e., as a mechanical spring. In the embodiment shown in the figures, the spring element 85 is designed as an annular cup spring. By hydraulically actuating the piston 34, the spring element 85 is elastically deformable, so that in the actuated state of the piston 34, the spring element 85 provides a spring force. By means of the spring force of the spring element 85, the brake disc element 20 can be displaced axially relative to the housing 12 as a result of the cessation of the hydraulic actuation of the piston 34, in particular into its initial position, whereby, for example, the frictional contact between the friction surfaces 30 and 44 and, for example, also between the friction surfaces 18 and 22 can be broken or is broken.This releases the brake assembly 14, also referred to simply as the brake, in particular completely. In this case, the spring element 85 is attached to a toothed carrier ring. During braking, i.e., during the hydraulic actuation of the piston 34, an outer, in particular the outermost, area of ​​the spring element 85 is elastically deformed, thereby providing the spring force to return the brake disc element 20, in particular to its initial position. If, for example, the brake disc element 20 wears, the spring element 85, in addition to its elastic deformation on the toothed carrier ring, is displaced axially towards the electric motor, i.e., towards the interior 70. As a result, the brake disc element 20 is always only returned by the elastic distance. Even if the brake disc element 20 wears, the brake clearance remains at least essentially constant.

[0059] It is evident that the intermediate element 82, which functions or is designed as a decoupling element, enables the piston 34, designed as a ring brake piston, and the transmission element 54, designed here as a pressure plate, to be joined together to form an assembly unit in a simple and cost-effective manner. During the joining process of the transmission element 54 with the piston 34, the intermediate element 82 is radially compressed by means of the chamfer F of the piston 34 until the intermediate element 82 engages, or snaps into, the groove 80 of the piston 34, which is designed here as a detent groove. In the state of the intermediate element 82 being arranged in the groove 80, it is elastically deformed, particularly radially, and thus pre-stressed. For example, the groove 78 is designed as an O-ring groove.The intermediate element 82, which is partially arranged in the grooves 78 and 80, results in a quasi-positive locking connection between the transmission element 54 and the piston 34. Very high forces are required to separate the transmission element 54 and the piston 34.

[0060] By introducing hydraulic fluid, for example oil, into the actuation chamber 52, a pressure, particularly oil pressure, is generated in the actuation chamber 52, which is, for example, an annular space. This pressure is caused by the hydraulic fluid. As a result, the piston 34 moves, particularly axially, towards the transmission element 54. During this movement, the intermediate element 82 is elastically deformed and thereby compressed and overpressed, so that the end face SF comes into direct contact with the support surface AF. An actuating force resulting from the pressure is then transmitted by the piston 34 directly to the transmission element 54 via the direct contact between the support surface AF and the end face SF, and subsequently to the brake disc elements 16, 20, and 42.By ceasing the hydraulic actuation of the piston 34, also known as releasing the brake, the pressure in the actuation chamber 52 drops again, causing the piston 34 to move away from the transmission element 54. This allows the intermediate element 82 to expand again. To ensure, for example, that the intermediate element 82 expands not only radially but also axially, a shoulder 86, also referred to as a shoulder surface, is arranged in the groove 78. This shoulder is formed, for example, by the groove base of the groove 78. The shoulder 86 is conical and thus follows an imaginary cone that widens axially towards the friction surfaces 18 and 22. The shoulder 86 causes the intermediate element 82 to be pushed away from the transmission element 54 or the support surface AF when the intermediate element 82 relaxes and thus expands.Since the intermediate element 82 is supported in the groove 80 of the piston 34, which is designed, for example, as a locking groove, the piston 34 and the transmission element 54 are separated from each other, especially when the intermediate element 82 relaxes and thus expands, and by means of the intermediate element 82 the piston 34 and the transmission element 54 can be advantageously thermally isolated from each other, i.e. decoupled.

[0061] It is evident that the brake disc element 20 of the brake assembly 14 is a friction disc which is axially displaceable, i.e., in the axial direction of the axle drive assembly 10 and thus of the brake assembly 14, relative to the housing 10 and relative to the brake disc elements 16 and 42. However, the brake disc element 20 (friction disc) is rotatable with the part 38 of the shaft 24 about the axis of rotation 26 relative to the brake disc elements 16 and 42 and relative to the housing 10. The shaft 24 is an output shaft by means of which the vehicle wheel can be driven by the output shaft and is thereby rotatable about the wheel's axis of rotation relative to the brake disc elements 16 and 42 and relative to the housing 10.

[0062] It is also apparent that the housing part 62, also referred to as intermediate cover, and the housing part 74, also referred to as end cover or side cover, form or are a housing assembly of the brake assembly 14, wherein the brake disc elements 16, 20 and 42 are each at least partially arranged in the housing assembly, i.e. in the receiving space 68 of the housing assembly.

[0063] It is also evident that the brake disc element 42 is a first counter-rotating disc, which is rotationally and axially fixed to the housing 10 and thus to the housing assembly. The housing assembly is therefore an integral part of the housing 10. The brake disc element 16 is a second counter-rotating disc, which is rotationally fixed to the housing assembly, and thus to the housing 10. However, the second counter-rotating disc is axially displaceable relative to the housing assembly, relative to the friction disc (brake disc element 20), and relative to the first counter-rotating disc (brake disc element 42).

[0064] Looks especially good Fig. Figures 4 to 7 show that the friction disc (brake disc element 20) has internal teeth 88 that engage with corresponding external teeth in the form of teeth 46. The external teeth (teeth 46) are provided on a connecting element 90, which in this case is separate from the friction disc and separate from the shaft 24. The connecting element 90 is separate from part 38 of the shaft 24, also referred to as the output shaft, and is permanently and rotationally fixed to part 38. A bellows 92, which surrounds at least a portion of the shaft 24 in the circumferential direction, is designated as such.

[0065] The toothing 46 is provided on the connecting element 90 such that the toothing 46 is permanently connected to the connecting element 90 in a rotationally fixed manner. In particular, the toothing 46 is formed by the connecting element 90. For example, the toothing 46 and the connecting element 90 are formed from a single piece and are thus integrally formed. Thus, for example, the connecting element 90 is a tooth carrier. For example, by the internal toothing 88 engaging with the corresponding mating toothing, the friction disc is permanently connected to the connecting element 90 in a rotationally fixed manner and is thus rotatable with the connecting element 90 about the axis of rotation 26 relative to the counter-rotating discs and relative to the housing 10 or the housing assembly. Furthermore, the connecting element 90 is rotatable with the part 38 about the axis of rotation 26 relative to the housing assembly and relative to the counter-rotating discs.

[0066] Looks especially good Fig. Figures 4 to 7 show the spring element 85, which is shaped like an annular cup and thus functions as an annular cup spring. The spring element 85 is, or acts as, a return spring, as will be explained in more detail below. The return spring partially surrounds the connecting element 90. For this purpose, the return spring (spring element 85) has a first section 94, which is designed, for example, as a first cylindrical segment. The section 94 is cylindrical on both its outer and inner circumferences and is thus designed in the form of a first straight circular cylinder, whose first cylinder axis, also referred to as the first central axis, coincides with the axis of rotation 26. The first straight circular cylinder is rotationally symmetrical with respect to its first cylinder axis.The first sub-section 94 encompasses a first length section L1 of the connecting element 90 in the circumferential direction at least partially, in particular at least predominantly and thus over more than 180 degrees or completely and thus over 360 degrees, so that the length section L1 is overlapped outwards by the first sub-section 94 in the radial direction of the axle drive device 10 and thus of the brake device 14.

[0067] The return spring (spring element 85) has a second subsection 96, which is a second cylindrical section. The second subsection 96 is cylindrical on both its inner and outer circumferences and thus forms a second right circular cylinder, whose second cylinder axis, also referred to as the second central axis, coincides with the first cylinder axis and with the axis of rotation 26. The second right circular cylinder is rotationally symmetrical with respect to the second cylinder axis. At least a portion of the toothing 46 is formed in the length range L1, such that the subsection 94 encompasses at least the portion of the toothing 46 as described.A second length section L2 of the connecting element 90, comprising length section L1, is radially overlapped inwards by the subsection 96 such that the second length section L2 at least partially, and in particular at least predominantly or completely, circumferentially surrounds the subsection 96. An axially extending direction of the second length section L2 is greater than an axially extending length of the first length section L1. The subsections 94 and 96 are connected to each other via a third subsection 98 of the spring element 85, also referred to as a return spring, wherein the subsection 98 is a spring section. The subsection 98 extends at least substantially in a plane that is perpendicular to the axial direction. In particular, the subsections 94, 96, and 98 are formed integrally, that is, from a single piece.

[0068] The return spring is connected to the connecting element 90 via an interference fit. The spring element 85 is formed separately from the connecting element 90. The interference fit allows for axial relative displacement between the return spring and the connecting element 90. Furthermore, the return spring is in resilient contact with the friction disc. For this purpose, the return spring, in particular the section 94, is supported in the axial direction at least indirectly, and in particular directly, on the friction disc, especially on a side SE1 of the friction disc (brake disc element 20) facing away from the brake disc element 16 in the axial direction.

[0069] The connecting element 90 has a machined surface FL against which the return spring, in particular the sub-section 94, abuts, forming an interference fit, in particular directly. In this case, the sub-section 96 abuts the machined surface FL in a radial direction from the inside out. The length section L3 is part of a third length section L3 of the connecting element 90, wherein the length section L3 has a third axially extending length that is greater than the axially extending length of length section L2 and greater than the axially extending length of length section L1. The machined surface FL is formed in or on the length section L3.In particular, the machined surface FL is an inner circumferential surface of the connecting element 90 and is cylindrical, thus forming a third right circular cylinder, whose third cylinder axis, also referred to as the third central axis, coincides with the first cylinder axis, the second cylinder axis, and the axis of rotation 26. The third right circular cylinder is rotationally symmetrical with respect to the third cylinder axis. Since, for example, the section 96 abuts directly against the machined surface FL in the radial direction, the second right circular cylinder abuts directly against the third right circular cylinder.

[0070] The third length of the length range L3, extending in the axial direction, coincides, for example, with an axial extension of the machined surface FL, whose axial extension is also referred to as the axial extension. The length range L2, which is overlapped and thus covered radially inwards by the sub-range 96 and therefore by the return spring, is also overlapped radially inwards by the axle drive device 10 and thus by the brake device 14 via its second axially extending length, so that the second axially extending length of the second length range L2 is also referred to as the overlap length, over which the sub-range 96 and thus the return spring overlaps the connecting element 90 radially inwards.Thus, the overlap length runs in the axial direction of the axle drive unit 10 and therefore of the brake unit 14. It can be seen that the axial extent of the machined surface FL is greater than the overlap length by a distance ST extending in the axial direction and larger than zero. As a result, a first sub-area of ​​the machined surface FL overlaps radially inwards by the sub-area 96 and thus by the return spring, while a second sub-area of ​​surface FL, extending axially and towards the end cap directly adjacent to the first sub-area of ​​surface FL, does not overlap radially inwards by the return spring. This second sub-area of ​​surface FL has the distance ST.

[0071] Since the length section L1 of the connecting element 90 is radially overlapped outwards by the subsection 94, and since at least part of the toothing 46 is arranged or formed with the length section L1, the return spring extends radially outside the external toothing and in an axial direction along the length section L1 of the connecting element 90, whose length section L1 is a subsection of the connecting element 90. The subsection 94 extends in the axial direction along the length section L1.

[0072] Fig. Figure 4 shows the brake device 14 in an unactuated state. In this unactuated state, an air gap is formed or arranged in the axial direction between the friction surfaces 30 and 44, so that no friction occurs or exists between the friction surfaces 30 and 44. Furthermore, as shown in Figure 4, the brake device 14 is in an unactuated state. Fig. As can be seen, in the unactuated state the return spring is relaxed, in particular completely. By actuating the brake device 14, in particular hydraulically, the hydraulic fluid is introduced into the actuating chamber 52, or the pressure of the hydraulic fluid contained in the actuating chamber 52 is increased. This causes the second counter-rotating disc to be moved axially towards the friction disc and the first counter-rotating disc, so that the friction surfaces 22 and 18 come into mutual contact. Since the second counter-rotating disc is moved axially towards the first counter-rotating disc, actuating the brake device 14 moves the second counter-rotating disc and the friction disc axially towards the first counter-rotating disc, thereby, for example, eliminating the aforementioned gap between the friction surfaces 30 and 44, and bringing the friction surfaces 30 and 44, the friction disc, and the first counter-rotating disc into direct contact with each other.Since the friction disc is arranged axially on the return spring in relation to the first counter-rotating disc, actuating the brake device 14 elastically deforms and thereby tensions the return spring. Fig. Figure 5 shows the brake assembly 14 in the actuated state. It can be seen that the return spring (spring element 85), designed as a ring-shaped spring, is elastically deformed and thus tensioned; however, there is, in particular, no axial displacement of the return spring relative to the connecting element 90 yet. Thus, the return spring is elastically deformed by the displacement of the friction disc, especially in the direction of the first counter-rotating disc, without any axial displacement of the return spring relative to the connecting element 90. This is the case, for example, when the friction linings 30 and 44 forming the friction surfaces, which are also referred to as brake linings, are new, i.e., not worn. The brake linings are also simply referred to as linings. Thus, Figure 5 shows that the return spring is elastically deformed by the displacement of the friction disc, particularly in the direction of the first counter-rotating disc, without any axial displacement of the return spring relative to the connecting element 90. Fig. 5 the braking device 14 in the actuated state of the braking device 14 and in a state in which the linings forming the friction surfaces 30 and 44 are new, i.e. not worn (unworn).

[0073] Fig. Figure 6 shows the brake device 14 in the actuated state and in a state in which the linings forming the friction surfaces 30 and 44 are worn, i.e., exhibit a certain degree of wear. Actuating the brake device 14 causes the return spring to deform elastically and thus become tensioned. Furthermore, the return spring is displaced axially towards the first counter-rotating disc relative to the connecting element 90. This causes, for example, the distance ST to increase compared to the state in which the brake device 14 is actuated and the linings forming the friction surfaces 30 and 44 are still unworn. Fig. 6. The return spring is therefore both tensioned and axially displaced relative to the connecting element 90°.

[0074] Fig. Figure 7 shows the brake device 14 in the unactuated state and in the previously mentioned state in which the linings forming the friction surfaces 30 and 44 are worn.

[0075] It is noticeable that the return spring is opposite the one in Fig. The state shown in 6 has rebounded and is therefore not or less elastically deformed, however, compared to the one in Fig. The condition shown in 4 is axially displaced in the axial direction and relative to the connecting element 90, as is also shown in the Fig. The condition shown in 6 is the case. Thus, the Fig. 6. Once the actuation of the brake device 14 is completed, as illustrated, the return spring can at least partially relax and thus spring back, thereby pushing the friction disc or the friction surface 30 away from the first counter-rotating disc or away from the friction surface 44, in particular pushing it back; however, the return spring remains in the position shown in Fig. 6 and Fig. 7 shown and compared to the one in Fig. 4 and Fig. The condition shown in section 5 is axially displaced in the direction of the first counter-rotating disc and relative to the connecting element 90. This is permitted by the interference fit between the return spring and the connecting element 90.

[0076] In other words, after braking, the friction disc is moved back to its initial position by the return spring, in particular by being pulled or pushed back. This releases the braking device 14, also simply referred to as the brake, in particular completely. It can be seen that the return spring is held on the connecting element 90, which is designed as a toothed carrier ring. When the brake is applied, and thus during the resulting braking process, the outermost part of the return spring is elastically deformed and thus tensioned, thereby ensuring the return of the friction disc. When the friction disc, or rather its lining forming the friction surface 30, wears down, the return spring, in addition to its elastic deformation, is also displaced axially along the connecting element 90 and thus in the direction of the first counter-rotating disc when the brake is applied.This ensures that the friction disc is always returned only by an elastic distance, the same amount by which the return spring elastically rebounds when the brake device 14 is released. Even with wear of the respective lining, the brake clearance remains essentially constant. Because the return spring is located within a brake radius on an existing component, in this case the connecting element 90, and surrounds the connecting element 90, a particularly space-saving arrangement of the return spring is possible.

[0077] It is evident from Fig. 4 to 7 particularly good that the ring-shaped return spring is arranged on an inner circumferential area of ​​the connecting element 90, wherein the inner circumferential area forms or has the machined surface FL.

[0078] The interference fit is formed between an inner circumferential surface of the connecting element 90 and an outer circumferential surface of the return spring, such that the outer circumferential surface of the return spring rests directly against the inner circumferential surface of the connecting element 90. The inner circumferential surface of the connecting element 90 forms the machined surface FL, and the outer circumferential surface of the return spring is formed by the section 96 of the return spring. During normal braking, the return spring is only elastically deformed and thus tensioned within its elastic range. The interference fit between the return spring and the connecting element 90, also simply referred to as a fit, is designed so that the return spring cannot move independently along the connecting element 90.Only when the return spring is subjected to greater stress, for example when the brake is applied and the linings forming the friction surfaces 30 and 44 are worn, does a force acting on the return spring, particularly from the friction disc, increase so much that the return spring, also simply referred to as a spring, is displaced axially along the connecting element 90 and in the direction of the first counter-rotating disc. Reference symbol list: 10 electric axle drive units 12 cases 14 Brake system 16 first brake disc element 18 first friction surface 20 second brake disc element 22 second friction surface 24 wave 26 axis of rotation 28 Double Arrow 30 third friction surface 32 Double Arrow 34 pistons 36 Double Arrow Part 38 40 joint 42 third brake disc element 44 fourth friction surface 46 gear teeth 48 teeth 50 hydraulic channel 52 Activity area 54 Transmission element 56 Cooling structure 58 Cooling structure 60 first housing part 62 second housing part 64 Case opening 66 warehouses 68 Recording room 70 Interior 72 surroundings 74 third housing part 76 lid openings 78 first groove 80 second groove 82 Intermediate element 84 Cantilever 85 spring element 86 Shoulder 88 Internal teeth 90 Connecting element 92 bellows 94 Sub-area 96 sub-area 98 Sub-area SE1 page L1 length range L2 length range L3 length range FL processed area ST route AF support surface F phase G Basic area M1 outer circumferential surface M2 inner circumferential surface SF front surface QUOTES INCLUDED IN THE DESCRIPTION

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

[0000] DE 10 2019 118 503 A1

[0002]

Claims

[1] Braking device (14) for a motor vehicle, comprising a friction disc (20) which is arranged axially between a first counter-running disc (42) and a second counter-running disc (16) of the braking device (14), wherein: - the friction disc (20) has internal teeth which engage in a counter teeth (46) provided on a connecting element (90) which is non-rotatably connected to an output shaft (24) and which are designed as external teeth; - an annular cup-shaped return spring (85) is arranged on an inner circumferential area of ​​the connecting element (90), which partially surrounds the connecting element (90) and is connected to the connecting element (90) via an interference fit and is in operative contact with the friction disc (20); - the connecting element (90) has a machined surface (FL) against which the return spring (85) rests, forming an interference fit; and - an axial extent of the machined area (FL) is greater than an overlap length over which the return spring (85) overlaps the connecting element (90). [2] Braking device (14) according to claim 1, characterized by , that: - a housing device (62, 74) is provided in which the friction disc (20) and the counter-running discs (16, 42) are arranged; - the first counter-rotating disk (42) is connected to the housing assembly (62, 74) in a rotationally and axially fixed manner; and - the second counter-rotating disc (16) is connected to the housing assembly (62, 74) in a rotationally fixed manner and is axially displaceable relative to the housing assembly (62, 74), relative to the friction disc (20) and relative to the first counter-rotating disc (42). [3] Braking device (14) according to claim 1 or 2, characterized by, that the return spring (85) extends radially outside the external toothing and in an axial direction along a partial area (L1) of the connecting element (90). [4] Motor vehicle, with at least one braking device (14) according to any of the preceding claims.

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