Brake system

Abstract

The invention relates to a brake system (1) of a motor vehicle (3), which can be electrically driven by an electric machine (2), the brake system (1) comprising a multi-disc brake (4) having a plurality of inner discs (5) and a plurality of outer discs (6), which can be frictionally connected by means of a brake actuator (7), the multi-disc brake (4) is housed in a brake housing (9) and the inner disc (5) or the outer disc (6) is connected to the rotor (8) of the electric machine (2) in a torque-transmitting manner, and the electric machine (2) comprises a rotor (8) coupled in a torque-transmitting manner to at least one wheel (10) of the motor vehicle (3), in which the multi-disc brake (4) is housed in a brake housing (9) and in which the inner disc (5) or the outer disc (6) is connected in a torque-transmitting manner to the rotor (8) of the electric machine (2).

Description

Technical Field

[0001] The invention relates to a braking system for a motor vehicle, which can be electrically driven by an electric motor, wherein the braking system comprises a multi-disc brake having a plurality of inner disks and a plurality of outer disks, the inner disks and the outer disks being frictionally connected by means of a brake actuator, and the electric motor comprising a rotor coupled to at least one wheel of the motor vehicle in a torque-transmitting manner. Background Art

[0002] Electric motors are increasingly being used to drive motor vehicles in order to create an alternative to internal combustion engines that require fossil fuels. Considerable efforts have been made to improve the suitability of electric drives for everyday use and also to be able to provide users with the driving comfort they are accustomed to. A detailed description of electric drives can be found in an article by Erik Schneider, Frank Fickl, Bernd Cebulski and Jens Liebold in the magazine ATZ, Vol. 113, May 2011, pp. 360 to 365, entitled: Hochintegrativ und Flexibel Elektrische Antriebseinheit für E-Fahrzeuge [Highly Integrative and Flexible Electric Drive Unit for E-Vehicles (Highly Integrated and Flexible Electric Drive Unit for Electric Vehicles)]. The article describes a drive unit for an axle of a vehicle, the drive unit comprising an electric motor arranged coaxially with a bevel gear differential.

[0003] Motor vehicles of this type with a hybrid or electrified drive train can not only accelerate but also brake with the aid of the electric motor. During braking, for example, the electric motor operates as a generator and the recovered energy is used to charge the battery. However, for safety reasons, additional mechanical braking devices are still required. For drives close to the wheels, such as wheel hub motors or electric axles, this leads to more difficult installation space conditions.

[0004] In particular, vehicles with electric wheel hub drives, so-called electric wheel drives, usually use brakes with disks to decelerate the vehicle. However, disk brakes with floating calipers, disk brakes with fixed calipers, drum brakes and multi-disc brakes are also known.

[0005] For example, DE 10 2019 120 409 A1 discloses a braking device for a wheel hub drive assembly, in which a brake mating part fixed relative to the circumferential direction has a cooling channel. The axially movable brake mating part is actuated via a brake cylinder. The brake mating part movable in the circumferential direction is designed as a disk carrier.

[0006] There is also an increasing demand to reduce or completely avoid the emission of brake dust, which usually occurs as particulate matter. Summary of the Invention

[0007] Therefore, an object of the present invention is to provide an improved braking system with high braking torque and low brake dust emission.

[0008] This object is achieved by a braking system for a motor vehicle, which can be electrically driven by means of an electric motor. The braking system includes a multi-disk brake having a plurality of inner disks and a plurality of outer disks. The inner disks and the outer disks can be frictionally connected by means of a brake actuator. The electric motor includes a rotor that is torque-transmittingly coupled to at least one wheel of the motor vehicle. The multi-disk brake is accommodated in a brake housing, and the inner disk or the outer disk is torque-transmittingly connected to the rotor of the electric motor.

[0009] This has the following advantages: The brake dust from the multi-disk brake can be kept within the brake housing, which helps to directly reduce the environmental impact. Another advantage of the braking system according to the present invention is that the unsprung mass on the wheel can be reduced. The steering angle of the corresponding wheel can also be increased by eliminating the brake arranged on the wheel.

[0010] The braking system according to the present invention has the function of braking the wheels of the motor vehicle to be braked by means of frictional connection. In particular, the multi-disk brake can be designed based on the functional principle of a dry or wet multi-disk brake. The multi-disk brake is arranged at a certain distance from the wheel in the driveline of the motor vehicle. The multi-disk brake is preferably coupled to the rotor of the electric motor.

[0011] The function of a multi-disc brake is to create a releasable frictionally engaged connection between the brake shaft and the connecting structure, which is usually arranged in a non-rotatable manner for this purpose to support the braking torque. For this purpose, the alternately arranged inner and outer discs of the disc pack can be brought into non-form-fitting or frictional contact by means of an assembly process via their respective friction linings by axial displacement and compression, such that the inner discs are arranged to rotate relative to the outer discs in a frictionally engaged manner about the common axis of rotation of the corresponding disc pack, or are arranged in a rotationally fixed manner relative to each other in the case of full frictional engagement. On the other hand, if the inner and outer discs are axially pushed away from each other by a disengagement process, no non-form-fitting contact exists between the inner and outer discs anymore, such that the inner and outer discs can rotate freely against each other and thus no torque or braking torque is transmitted between the inner and outer discs.

[0012] A multi-disc brake typically includes at least two inner discs and / or two outer discs. The inner discs are preferably arranged in a non-rotatable manner on an inner multi-disc carrier, and the outer discs are preferably arranged in a non-rotatable manner on an outer multi-disc carrier. The inner multi-disc carrier is preferably connected to the brake shaft, and the outer multi-disc carrier is preferably connected in a non-rotatable manner to the connecting structure, or vice versa.

[0013] The inner and outer discs form the disc pack of the multi-disc brake. In the disc pack, a plurality of inner and outer discs are preferably arranged alternately in the axial direction. The torque or braking torque that can be transmitted by the multi-disc brake between the inner and outer discs can be adjusted by the number and design of the inner and outer discs.

[0014] The inner discs have the function of transmitting torque, in particular in a non-form-fitting or frictionally engaged manner, from the outer discs to the inner multi-disc carrier. The inner discs can be designed in particular as annular discs. The inner discs can be connected in a non-rotatable manner to the inner multi-disc carrier of the multi-disc brake. It can also be provided that the inner discs are axially displaced relative to the inner multi-disc carrier, for example by means of corresponding teeth, to form a frictional connection with the outer discs.

[0015] The outer discs have the function of transmitting torque, in particular in a non-form-fitting or frictionally engaged manner, from the inner discs to the outer multi-disc carrier. The outer discs can be designed in particular as annular discs. The outer discs can be connected in a non-rotatable manner to the outer multi-disc carrier of the multi-disc clutch. It can also be provided that the outer discs are axially displaced relative to the outer multi-disc carrier, for example via corresponding teeth, to form a frictional connection with the inner discs. For example, the outer multi-disc carrier can be designed as an outer disc clutch cage.

[0016] The disk pack can be accommodated in one or more multi-disk carriers and can in particular also be guided for linear movement. For this purpose, the inner disks can be accommodated in inner multi-disk carriers and the outer disks can be accommodated in outer multi-disk carriers. In order to form a linearly displaceable offset of the inner disks relative to the outer disks (or in order to form a linearly displaceable offset of the outer disks relative to the inner disks), the inner disks can be connected to the inner multi-disk carriers via internal spline teeth and / or the outer disks can be connected to the outer multi-disk carriers in a torque-transmitting manner via external spline teeth.

[0017] The multi-disk brake can preferably include spring elements. The spring elements have the task of using spring force to move the inner and outer disks relative to each other into a predetermined position. This predetermined position typically corresponds to the "normally open" or "normally closed" operating state of the multi-disk brake, which means that when the brake actuator is not actuated, the inner and outer disks are pressed against each other or released by the spring elements.

[0018] The multi-disk brake can also have a shift piston. The shift piston has the function of converting the engagement process or disengagement process specified by the brake actuator into an axial displacement of the inner and / or outer disks for the purpose of establishing a frictional connection during braking or releasing the frictional connection when the multi-disk brake is released.

[0019] The multi-disk brake is preferably arranged in a brake housing. The brake housing encloses the multi-disk brake. The brake housing can also accommodate one or more brake actuators. The brake housing can also be part of a cooling system for the electric motor and can be designed such that cooling fluid can be supplied to the braking system via the brake housing and / or heat can be dissipated to the outside via the housing surface. The brake housing also protects the supplementary brake from external mechanical and / or chemical influences. The brake housing can in particular be formed from a metallic material. Advantageously, the brake housing can be formed from a metallic casting material such as gray cast iron or cast steel. In principle, it is also conceivable to form the brake housing completely or partially from plastic. Furthermore, the brake housing can be designed as a single piece or several parts. The brake housing can also be designed completely or partially as part of the motor housing of the electric motor or as part of the transmission housing of a transmission coupled to the electric motor. Preferably, the brake housing and the motor housing or the transmission housing form a single structural unit. For example, the brake housing can be bolted to the motor housing or the transmission housing. The brake housing is preferably designed such that the dust generated during braking cannot escape from the brake housing. This prevents unnecessary pollution of the environment by brake dust. By encapsulating the braking system in this way, brake noise can also be reduced. Another advantageous aspect of this encapsulation is that the braking performance of the braking system is independent of the weather conditions outside the motor vehicle.

[0020] In particular, the brake actuator has the function of enabling the brake, setting the brake into a frictionally engaged operating state, and releasing it from the friction connection. In particular, the brake actuator can be actuated pneumatically, hydraulically, by an electric motor, mechanically, electromagnetically, or by any combination thereof. The brake actuator is preferably configured as an electromechanical brake actuator.

[0021] The braking system according to the invention is preferably provided for a motor vehicle that can be electrically driven by means of an electric motor. The electric motor, within the meaning of this application, serves to convert electrical energy into mechanical energy and / or to convert mechanical energy into electrical energy, and generally comprises a stationary part known as the stator or stationary anchor and a part known as the rotor or runner which is arranged to be movable relative to the stationary part. In connection with the present invention, the electric motor can in particular be designed as a rotary machine. In the case of such an electric rotary machine, a distinction is made between a radial-flow machine and an axial-flow machine. The radial-flow machine is characterized in that the magnetic field lines extend in the radial direction in the air gap formed between the rotor and the stator, while in the case of the axial-flow machine, the magnetic field lines extend in the axial direction in the air gap formed between the rotor and the stator. In the context of the present invention, the electric motor is in particular intended for use within the powertrain of a hybrid or fully electric motor vehicle. In particular, the electric motor is dimensioned such that a vehicle speed of more than 50 km / h, preferably more than 80 km / h, and in particular more than 100 km / h can be achieved. The electric motor particularly preferably has an output of more than 30 kW, preferably more than 50 kW, and in particular more than 70 kW. Furthermore, it is preferred that the electric motor provides a speed of more than 5000 rpm, particularly preferably more than 10,000 rpm, and very particularly preferably more than 12,500 rpm.

[0022] The electric motor can have a housing, also known as a motor housing. The motor housing encloses the electric motor. The motor housing can also accommodate the control and power electronics unit, and preferably can also accommodate at least part of the braking system. The motor housing can also be part of a cooling system for the electric motor and can be designed such that cooling fluid can be supplied to the electric motor via the motor housing and / or heat can be dissipated to the outside via the motor housing surface. Additionally, the motor housing protects the electric motor and any electronics that may be present from external influences. The motor housing of the electric motor can in particular be formed from a metallic material. Advantageously, the motor housing can be formed from a metallic casting material such as gray cast iron or cast steel. In principle, it is also conceivable to form the motor housing completely or partially from plastic. Furthermore, the motor housing of the electric motor can be designed as one piece or several parts.

[0023] The rotor is the rotating (turning) part of the electric machine. The rotor particularly includes a rotor shaft and one or more rotor bodies formed by a rotor lamination stack, which is arranged on the rotor body in a non-rotatable manner. The rotor shaft can be hollow, which firstly results in weight reduction and secondly allows the supply of lubricant or coolant to the rotor body. In particular, the rotor shaft can be coupled to the brake shaft of a supplementary brake.

[0024] The electric machine and / or the multi-disc brake can preferably be coupled to a transmission, which is particularly designed to generate a drive torque for a motor vehicle. The drive torque is particularly preferably a main drive torque such that the motor vehicle is driven only by the drive torque.

[0025] In particular, it can be provided that the electric machine and / or the multi-disc brake and the transmission are arranged in a common powertrain housing. Alternatively, the electric machine can of course also have a motor housing and the transmission can of course also have a transmission housing, whereupon a structural unit can then be realized by fixing the transmission assembly relative to the electric machine. This structural unit is sometimes also referred to as an electric axle. The powertrain housing is preferably formed from a metallic material, particularly preferably from aluminum, gray cast iron or cast steel, in particular by means of a one-piece forming process such as casting or die-casting. However, in principle, the powertrain housing can also be formed from a plastic material. The powertrain housing can particularly preferably have a cup-shaped basic shape such that the electric machine and the transmission can be inserted into the powertrain housing via the open end face of the powertrain housing.

[0026] The electric machine preferably has a motor housing and / or the transmission has a transmission housing, whereupon the structural unit can then be realized by fixing the transmission relative to the electric machine. The transmission housing is a housing for accommodating the transmission. The transmission housing has the following tasks: guiding the existing shafts via bearings and giving the wheels (cam discs, where applicable) the degrees of freedom required under all loads without impeding the rotation of the wheels and possible path movements and absorbing the bearing forces and support torques. The transmission housing can be designed as a single-shell or multi-shell, i.e., non-separated or separated. In particular, the transmission housing should be able to suppress noise and vibrations and safely absorb hydraulic fluid. The transmission housing is preferably formed from a metallic material, particularly preferably from aluminum, gray cast iron or cast steel, in particular by means of a one-piece forming process such as casting or die-casting.

[0027] Furthermore, the transmission can preferably be configured as a planetary gear device or include a planetary gear device. The planetary gear device can preferably have a sun gear and a number of planet gears as well as a ring gear, the number of planet gears meshing with the sun gear and being rotatably mounted in a planet gear carrier, the number of planet gears rotating around the sun gear, the ring gear being arranged coaxially with the sun gear and the planet gears rolling in the ring gear.

[0028] In addition, the transmission may have a differential transmission. A differential transmission is an epicyclic gear device having one driver and two output parts. A differential transmission generally has the following function: driving two wheels of a motor vehicle such that the wheels can rotate at different speeds during a turn, but with the same driving force.

[0029] In order to implement different drive or operation modes for a motor vehicle, one or more disengaging clutches may be arranged in the torque path between the electric machine and the wheels. For example, a disengaging clutch may be arranged between the output part of the electric machine and the input part of the transmission, such that the electric machine can be disconnected from the transmission, thereby allowing the motor vehicle to operate in a coasting mode. It is also conceivable to arrange the disengaging clutch between the output part of the transmission and one or more wheels, thereby also allowing the motor vehicle to operate in a coasting mode. Finally, the disengaging clutch may also be arranged between the input part of the braking system and the output part of the electric machine, which allows the braking system to be completely disconnected from the electric machine.

[0030] For the purposes of the present application, a motor vehicle is a land vehicle that is moved by machine power and is not restricted by railway tracks. A motor vehicle may be selected, for example, from the group consisting of passenger cars, trucks, scooters, light motor vehicles, motorcycles, buses / coaches or tractors.

[0031] Advantageous embodiments of the present invention are specified in the dependent claims. The features listed separately in the dependent claims can be combined with one another in a technically meaningful manner and can define other embodiments of the present invention. In addition, the features indicated in the claims are explained and illustrated in more detail in the description, wherein other preferred embodiments of the present invention are shown.

[0032] According to an advantageous embodiment of the present invention, it may be provided that the brake actuator is an electromechanical brake actuator comprising an electric drive and a transmission. According to another preferred further improvement of the present invention, it may also be provided that the electric drive is designed as an electric motor. The electric motor may be designed as a linear drive or a rotary drive.

[0033] Furthermore, according to an equally advantageous embodiment of the invention, it may be provided that the transmission means comprises a spindle drive having a threaded spindle and a spindle nut, in particular a ball screw drive, wherein the spindle nut is coupled to the inner or outer disk such that rotation of the threaded spindle causes translational displacement of the inner or outer disk to generate or release a frictional connection. The spindle drive thus converts a rotational movement into a linear movement by means of the threaded spindle and the spindle nut, and the threaded spindle and the spindle nut are coupled to each other such that they convert the rotational movement of the threaded spindle or the spindle nut into a linear movement of the threaded spindle or the spindle nut. In its simplest form, the spindle drive may consist of a threaded spindle and a spindle nut, wherein the thread of the threaded spindle meshes directly into the corresponding internal thread of the spindle nut, and wherein sliding friction occurs along the mutually engaging thread flanks.

[0034] According to a further particularly preferred embodiment of the invention, it may be provided that the multi-disk brake is designed as a multi-disk brake for wet operation. In particular, this enables the disk pack to be cooled and heat to be dissipated from the multi-disk brake.

[0035] Furthermore, the invention may also be further improved such that the transmission means of the brake actuator is arranged within the brake housing. In an equally preferred embodiment variant of the invention, it may also be provided that the electric drive is located outside the brake housing. This means that the electric drive can be arranged outside the wet chamber of the brake housing.

[0036] It may also be advantageous to further improve the invention such that the spindle drive is arranged radially outside the outer disk of the multi-disk brake within the brake housing, which contributes to an axially particularly compact multi-disk brake system.

[0037] According to a further preferred embodiment of the object of the invention, it may be provided that the spindle nut is connected to an annular piston which forms an annular contact surface in contact with the outermost one axially of the inner or outer disks. This ensures that the multi-disk brake can be actuated without the risk of jamming.

[0038] Finally, the invention may also be advantageously designed such that the inner disks are non-rotatably connected to an inner multi-disk carrier, which in turn is non-rotatably coupled to the brake shaft, which also contributes to a compact design. Preferably, the brake shaft may also have at least one fluid channel through which hydraulic fluid can be fed into the interior of the brake housing. Description of the Drawings

[0039] The invention will now be explained in more detail with reference to the drawings without limiting the general concept of the invention.

[0040] In the drawings:

[0041] Figure 1 A motor vehicle with an electric drive is shown in a schematic block diagram switching view.

[0042] Figure 2 An axle drive train with a braking system is shown in a schematic axial sectional view.

[0043] Figure 3 A detailed view of the braking system is shown in a schematic axial sectional view. Detailed Description

[0044] Figure 1 The braking system 1 of the motor vehicle 3 is shown, which can be electrically driven by means of an electric motor 2.

[0045] As can be seen in Figure 2 The braking system 1 includes a multi-disc brake 4 having a plurality of inner discs 5 and a plurality of outer discs 6, and the inner and outer discs can be frictionally connected by means of a brake actuator 7. The electric motor 2 of the axle drive train 39 has a rotor 8 that is torque-transmittingly coupled to at least one wheel 10 of the motor vehicle 3. A disengaging clutch 37 and a transmission assembly 38 are arranged in the torque flow between the electric motor 2 and the wheel 10. The disengaging clutch 37 allows the electric motor 2 to be disconnected from the drive path, so that for example this can be used to set the motor vehicle into a coasting mode.

[0046] The multi-disc brake 4 is received in a brake housing 9, and the inner disc 5 or the outer disc 6 is torque-transmittingly connected to the rotor 8 of the electric motor 2.

[0047] In the illustrated design example, the brake actuator 7 is designed as an electromechanical brake actuator including an electric drive 11 and a transmission 12. The electric drive 11 is designed as an electric motor. The transmission 12 is configured as a spindle drive 13 having a threaded spindle 14 and a spindle nut 15, wherein the spindle nut 15 is coupled to the inner disc 5 or the outer disc 6 such that rotation of the threaded spindle 14 causes translational displacement of the inner disc 5 or the outer disc 6 to create or release a frictional connection. In the illustrated embodiment, the multi-disc brake 4 is designed as a multi-disc brake 4 for wet operation.

[0048] The spindle drive 13 of the brake actuator 7 is arranged within the brake housing 9, while the electric drive 11 is positioned outside the brake housing 9. The spindle drive 13 is arranged radially outside the outer disks 6 of the multi-disk brake 4 within the brake housing 9. The spindle nut 15 is connected to an annular piston 16 which forms an annular contact surface 17 that contacts the axially outermost one of the inner disk 5 or the outer disk 6. The inner disk 5 is non-rotatably connected to an inner multi-disk carrier 18 which is in turn non-rotatably coupled to the brake shaft 19. The brake shaft 19 has a fluid passage 20 through which hydraulic fluid 21 can be fed into the interior of the brake housing 9.

[0049] As can be clearly seen in Figure 3 a disk pack 22 is provided for generating braking torque. The disk pack includes a number of axially displaceable outer disks 6 designed as steel disks and a number of axially displaceable inner disks 5 designed as friction disks. The outer disks 6 are rotationally fastened by corresponding geometries in an outer multi-disk carrier 28. On the one hand, the displacement range of the outer disks 6 is limited by a fixed support geometry. For example, the outer disks can be arranged within the brake housing 9. On the other hand, the displacement range of the outer disks 6 is limited by a contact geometry arranged on the annular piston 16. The annular piston 16 can be axially displaced by the arrangement described below.

[0050] The inner disks 5 are fastened against rotation by corresponding geometries arranged within the inner multi-disk carrier 18. The displacement range of the inner disks 5 is limited by the outer disks 6. In the non-actuated state when no braking torque is generated, there is a gap between each of the inner disks 5 and the outer disks 6. The inner multi-disk carrier 18 is arranged on the brake shaft 19 such that both the input torque and the input speed are transmitted. These input torque and input speed are transmitted from the rotor shaft 36 to the brake shaft 19 via a connection geometry 31 arranged on the brake shaft 19.

[0051] The brake housing 9 is designed such that one or more wet chambers 27 are produced. These wet chambers are flushed with hydraulic fluid 21 during operation. The hydraulic fluid 21 is fed via a fluid channel 20 arranged concentrically with the brake shaft 19 into a concentric and axially extending channel section 33 arranged in the brake shaft 19. From this channel section, the hydraulic fluid 21 enters one or more radially extending channel sections 34, which distribute the hydraulic fluid 21 to the disk pack 22 and through the outer multi-disk carrier 28 via the inner multi-disk carrier 18. During braking, the hydraulic fluid 21 absorbs the heat generated, and the heated hydraulic fluid 21 is discharged via the outlet 32. The multi-disk brake 4 is connected to a brake cooling circuit 41, and the heat is dissipated from the brake housing 9 via this brake cooling circuit and fed to a heat exchanger 40. The heat exchanger 40 can in turn be coupled to a thermal management system, and the dissipated heat is then reused within this thermal management system.

[0052] The brake shaft 19 is mounted in the brake housing 9 via rolling bearings 29, 35. A radial sealing element 30 arranged between the brake housing 9 and the brake shaft 19 seals the wet chamber 27 against the environment.

[0053] The axial force applied to the disk pack 22 to generate the braking torque is generated by means of an electric drive 11 and a transmission 12, which is connected to the electric drive 11 such that torque and speed can be transmitted. The electric drive 11 is arranged outside the brake housing 9, and the transmission 12 is arranged inside the brake housing 9 and the wet chamber 27. The transmission 12 is configured as a spindle drive 13, which has a threaded spindle 14, which is rotatably arranged in the brake housing 9 via rolling bearings 24, 25. The threaded spindle 14 and the brake housing 9 are sealed against the environment by a radially acting sealing element 23, which is arranged in the wet chamber 27.

[0054] The threaded spindle 14 has an external thread, which can be designed with a serrated, trapezoidal or ball-circulating profile. The associated spindle nut 15 meshes directly with this external thread or via an intermediate member. This converts the rotation of the threaded spindle 14 into an axial displacement of the spindle nut 15. For example, the movement range of the spindle nut 15 can be limited on the one hand by the brake housing 9 and on the other hand by a stop geometry 26 arranged on the threaded spindle 14. This design converts the torque generated by the electric drive 11 into an axial force, which is introduced into the disk pack 22 via the spindle nut 15 and an annular piston 16 connected to this spindle nut, thereby generating a braking effect.

[0055] For example, the power consumed by the electric drive 11 can be used to control the movement range of the annular piston 16. The contact torque between the annular piston 16 and the disk pack 22 on their contact surface 17 can be determined via their lift. Alternatively, a conventional limit switch can be arranged. The annular piston 16 can be rotationally fixed and axially guided, for example, via two or more posts and sliding bearings, toothing or several guide blocks running in a housing groove.

[0056] The invention is not limited to the embodiments shown in the drawings. Therefore, the above description should not be regarded as restrictive, but rather as illustrative. The appended claims should be understood to mean that the stated features are present in at least one embodiment of the invention. This does not exclude the presence of other features. In the case where the claims and the above description define a "first" feature and a "second" feature, such naming is used to distinguish between two features of the same type and does not define a priority order.

[0057] List of reference signs

[0058] 1 Brake system

[0059] 2 Electric motor

[0060] 3 Motor vehicle

[0061] 4 Multi-disc brake

[0062] 5 Inner disk

[0063] 6 Outer disk

[0064] 7 Brake actuator

[0065] 8 Rotor

[0066] 9 Brake housing

[0067] 10 Wheel

[0068] 11 Drive

[0069] 12 Transmission

[0070] 13 Spindle drive

[0071] 14 Threaded spindle

[0072] 15 Spindle nut

[0073] 16 Annular piston

[0074] 17 Contact surface

[0075] 18 Inner multi-disc carrier

[0076] 19 Brake shaft

[0077] 20 Fluid passage

[0078] 21 Hydraulic fluid

[0079] 22 Disc pack

[0080] 23 Sealing element

[0081] 24 Rolling bearing

[0082] 25 Rolling bearing

[0083] 26 Stop geometry

[0084] 27 Wet chamber

[0085] 28 Outer multi-disc carrier

[0086] 29 Rolling bearing

[0087] 30 Sealing element

[0088] 31 Connection geometry

[0089] 32 Outlet

[0090] 33 Channel section

[0091] 34 Channel section

[0092] 35 Rolling bearing

[0093] 36 Rotor shaft

[0094] 37 Disengaging clutch

[0095] 38 Transmission assembly

[0096] 39 Axle drive train

[0097] 40 Heat exchanger

[0098] 41 Brake cooling circuit.

Claims

1. A braking system (1) of a motor vehicle (3), said braking system being electrically drivable by an electric motor (2), wherein, The braking system (1) comprises a multi-disc brake (4) having a plurality of inner discs (5) and a plurality of outer discs (6), the inner and outer discs being frictionally connectable by means of a brake actuator (7), and the electric machine (2) comprises a rotor (8) which is torque-transmittingly coupled to at least one wheel (10) of the motor vehicle (3). It is characterized in that the multi-disc brake (4) is received in a brake housing (9), and the inner disc (5) or the outer disc (6) is torque-transmittingly connected to the rotor (8) of the electric machine (2).

2. The braking system (1) according to claim 1, It is characterized in that the brake actuator (7) is an electromechanical brake actuator comprising an electric drive (11) and a transmission (12).

3. The braking system (1) according to claim 2, It is characterized in that the electric drive (11) is designed as an electric motor.

4. The braking system (1) according to claim 2 or 3, It is characterized in that the transmission (12) comprises a spindle drive (13), in particular a ball screw drive, having a threaded spindle (14) and a spindle nut (15), wherein the spindle nut (15) is coupled to the inner disc (5) or the outer disc (6) such that rotation of the threaded spindle (14) causes translational displacement of the inner disc (5) or the outer disc (6) to produce or release the frictional connection.

5. The braking system (1) according to any one of the preceding claims, It is characterized in that the multi-disc brake (4) is designed as a multi-disc brake (4) for wet operation.

6. The braking system (1) according to any one of claims 2 to 5 preceding, It is characterized in that the transmission (12) of the brake actuator (7) is arranged within the brake housing (9).

7. The braking system (1) according to any one of claims 2 to 6 preceding, It is characterized in that the electric drive (11) is arranged outside the brake housing (9).

8. The braking system (1) according to any one of claims 4 to 7 preceding, It is characterized in that the spindle drive (13) is arranged radially outside the outer disc (6) of the multi-disc brake (4) within the brake housing (9).

9. The braking system (1) according to any one of claims 4 to 8 preceding, It is characterized in that the spindle nut (15) is connected to an annular piston (16) which forms an annular contact surface (17) in contact with the outermost axially one of the inner disc (5) or the outer disc (6).

10. The braking system (1) according to any one of the preceding claims, It is characterized in that the inner disc (5) is non-rotatably connected to an inner multi-disc carrier (18) which is in turn non-rotatably coupled to a brake shaft (19).

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