Drive brake unit and vehicle

Abstract

The present invention relates to a drive brake unit (2) comprising a friction brake unit (1) and a wheel-integrated electric motor for driving a vehicle. The friction brake unit (1) includes at least one brake actuator (3) for actuating the friction brake unit (1) and generating a braking torque. Protection against environmental influences is to be improved. For this purpose, the friction brake unit (1) comprises a friction brake housing (8), wherein the friction brake housing (8) is sealed from the environment with respect to the ingress and egress of brake dust and fluids by means of at least one sealing element (13A). This prevents the ingress of dirt and fluids from the outside into the drive brake unit and the egress of brake dust from the drive brake unit. The invention further relates to a vehicle comprising at least two drive brake units (2) of this type.

Description

The present invention relates to a drive brake unit comprising a friction brake unit and a wheel-integrated electric motor for driving a vehicle, wherein the friction brake unit includes at least one brake actuator for actuating the friction brake unit and generating a braking torque. The invention further relates to a vehicle comprising at least two of the aforementioned drive brake units. In this application, the term "drive brake unit" refers to a combination of a wheel-integrated electric vehicle drive motor and a friction brake unit. Whenever this application refers to an electric motor, it always means the wheel-integrated electric motor used to drive the vehicle. If a different electric motor is meant, this will be explicitly stated. Such a drive brake unit is known, for example, from KR20230021347A, in which a disc brake with a fixed caliper is combined with a wheel-integrated electric motor. The drive brake unit has numerous connections for power supply, signal connection of the electric motor, cooling of the drive brake unit, and hydraulic lines for the brake caliper. Brake dust can escape freely from the disc brake, and fluids (such as rainwater) can enter the disc brake. The wheel-integrated electric motor is significantly more sensitive to environmental influences such as dirt and rainwater than the friction brake unit. However, the friction brake unit itself is also a source of brake dust, the emission of which should be reduced, for example, due to environmental regulations. The invention is therefore based on the objective of providing a friction brake unit that at least partially solves the aforementioned problem. According to the invention, this problem is solved by a drive brake unit according to claim 1 and a vehicle according to claim 16. Accordingly, a drive brake unit as described above is provided, in which the friction brake unit comprises a friction brake housing, wherein the friction brake housing is sealed against an environment with respect to the ingress and egress of brake dust and fluids by means of at least one sealing element. This solution prevents dirt and liquids from entering the drive brake unit from the outside and brake dust from escaping from the drive brake unit. This reduces fine dust emissions and the susceptibility of the friction brake unit to corrosion (the latter being particularly important for disc brakes). However, an internal seal between the friction brake unit and the electric motor is also possible. The friction brake housing can, for example, comprise a housing cover and at least one sealing element to connect the friction brake housing to a stator component of the wheel-integrated electric motor. The friction brake housing can also be partially formed by the stator component, for example, in the form of a housing circumferential wall that is connected to a housing cover by means of a sealing element (e.g., a circumferential seal). A circumferential wall of the friction brake housing can also exist as a separate component and be connected to the stator component. It is also possible for the housing circumferential wall and a sectionally deformable sealing element to be formed integrally from a single component. In this document, "engine rotation axis," "axial," or "axial direction" refers to the direction parallel to the axis of rotation of the vehicle wheel or drive rotor, while "radial" or "radial direction" refers to the direction(s) perpendicular to said axis of rotation. The direction of rotation / circumference refers to the tangential directions along imaginary circular paths of constant radius around the engine's axis of rotation in planes perpendicular to the engine's axis of rotation. The actuation direction of the brake actuator can essentially be parallel to the axis of rotation of the vehicle wheel. Preferably, the friction brake housing of the friction brake unit comprises an elastically deformable sealing element that allows elastic deformation of the friction brake housing during actuation of the brake actuator. This accommodates the varying axial length of the brake actuator over the actuation stroke (particularly in the case of disc brake actuators). The friction brake housing can then lengthen and shorten in the actuation direction or axial direction together with the brake actuator. Preferably, a sealing element comprises a housing bellows to allow elastic extension of the friction brake housing parallel to the actuation direction of the brake actuator. The housing bellows can be integrated into a circumferential wall of the friction brake housing, so that a housing cover or an outer surface of the housing is displaced along with the elastic extension of the friction brake housing parallel to the direction of movement of the brake actuator. In one embodiment, a friction brake housing of the friction brake unit comprises a connection sealing element that seals the passage of a movable hydraulic connection of the friction brake unit extending from the friction brake housing. The connection sealing element is configured to extend elastically when the movable hydraulic connection moves relative to the friction brake housing during actuation of the brake actuator. In this embodiment, the friction brake housing can be designed such that the brake actuator itself has sufficient space throughout the entire actuation stroke. However, particularly for a hydraulic connection, elastic extension of the sealed space of the friction brake unit may still be necessary along the actuation stroke.However, it may be sufficient to seal the movable hydraulic connection of the friction brake unit, extending from the friction brake housing, in such a way that the connection sealing element can extend elastically. The remaining axial expansion of the friction brake housing can then remain unchanged when the brake actuator is actuated. The hydraulic connection can, in particular, be a hydraulic connection of a hydraulic disc brake. It is preferred if the connection sealing element around the movable hydraulic connection is designed as an annular bellows. This allows the hydraulic connection to move while simultaneously sealing the friction brake unit. In one embodiment, the friction brake housing comprises a housing cover, wherein a circumferential seal is arranged between the housing cover and the remainder of the friction brake housing. This circumferential seal can be arranged in a corresponding circumferential groove of the housing cover or of the remainder of the friction brake housing. In a preferred embodiment, the friction brake unit comprises at least two components that can be electrically connected to a vehicle, wherein the friction brake housing has a common connection geometry for the at least two components that can be electrically connected to a vehicle. This allows at least some of the electrical connection lines to be consolidated into common cables or cable harnesses, and reduces the number of penetrations in the friction brake housing that require sealing. Furthermore, the position of the connection geometry can be varied within a certain range and thus adapted to the spatial conditions in the area of ​​the steering knuckle and the wheel suspension, so that the cable(s) to be connected to the connection geometry can be connected with as little installation space as possible. This also simplifies assembly and maintenance. The term "electrically connectable component to a vehicle" is to be understood as meaning that the component requires a connection to a power supply and / or an electrical signal connection for its intended function. Preferably, the connection geometry is designed so that at least two components can be connected to the vehicle via a single cable. This also simplifies installation. Preferably, the connection geometry is integrated into a housing cover of the friction brake housing, wherein the housing cover is sealed to a remaining part of the friction brake housing or the stator component by means of a sealing element with a housing bellows, in order to allow the connection geometry to be shifted parallel to the actuation direction of the brake actuator. This makes it possible, on the one hand, to consolidate the component connections for the components that can be electrically connected to a vehicle in the housing cover. On the other hand, depending on the friction brake unit, adapted housing covers can be provided to consolidate the connection of different components. It is preferred if an electrically connectable component to a vehicle is an electrically actuated parking brake device. Depending on the type of parking brake device, prior art may require the connection of several electrical cables to the friction brake unit. The invention offers corresponding advantages for friction brake units with integrated parking brake devices during assembly and maintenance. It is preferred if the electrically actuated parking brake device comprises a parking brake actuator integrated into a hydraulically actuated service brake actuator. Such service brakes with an integrated parking brake device have additional components that are electrically connected to the vehicle and benefit from the present invention. Preferably, the electrically actuated parking brake device is integrated as a transmission lock into an electromechanically actuated service brake actuator. Compared to hydraulic brakes, such fully electric friction brake units have at least an additional power supply and, in many cases, additional signal and sensor lines, which would require separate cable connections in the prior art and which are particularly advantageous according to the invention. In one embodiment, a component electrically connectable to a vehicle is a brake pad wear indicator. Visual inspection of brake pad wear may not be possible depending on the design of the drive brake unit. A brake pad wear indicator may be necessary for safety reasons when the friction brake unit is designed to last the lifetime of the drive brake unit (i.e., no need to replace the brake pads under normal circumstances). Accordingly, such a friction brake unit benefits from the solution according to the invention, as the additional cable connection can be consolidated. Preferably, a component that can be electrically connected to a vehicle is a brake force sensor or brake torque sensor. Preferably, intermediate geometries for at least two of the components electrically connectable to a vehicle are arranged in a housing cover of a friction brake housing on a side facing the friction brake unit. These intermediate geometries can be connected to component terminals of the components, with the electrical leads from the intermediate geometries in the housing cover being brought together in the common connection geometry. The intermediate geometries can be arranged on the inside of the housing cover, while the common connection geometry is arranged on an outside (facing the vehicle) of the friction brake housing. The friction brake unit is preferably a disc brake, in particular with a brake caliper designed as a floating caliper. Preferably, the wheel-integrated electric motor and the wheel-integrated friction brake unit are arranged along the motor rotation axis of the electric motor, at least partially axially overlapping with the electric motor.In one embodiment, the electric motor is a double-rotor radial flux motor in which a drive stator is arranged radially between an outer drive rotor and an inner drive rotor, the drive stator comprising coils for generating a magnetic field. Permanent magnets can be arranged on both the outer and inner drive rotors, facing the drive stator. Such wheel-integrated electric motors exhibit particularly high average efficiency (even in the low-load range). The outer and inner drive rotors can be connected via a rotor base. The rotor base and outer drive rotor can jointly have a pot shape, with the outer and inner drive rotors extending axially from the rotor base. The outer drive rotor and the rotor base can be manufactured in one piece. The inner drive rotor can be attached to the rotor base as an axially extending flange.A base plate extending essentially in a radial direction can support the drive stator. The base plate, the external drive rotor, and the rotor base can essentially form a motor housing. Preferably, the drive brake unit includes a wheel-integrated inverter designed to convert the vehicle's direct current into alternating current for the electric motor. This solution allows the use of smaller diameter cables (low-voltage DC cables) to power the wheel-integrated electric motor. This saves further installation space in the area of ​​the wheel suspension / steering knuckle. Preferably, the drive brake unit includes active liquid cooling, which comprises a cooling channel in a base plate of the electric motor that supports the drive stator. Active liquid cooling allows for even better protection of the heat-sensitive components (especially permanent magnets and the electronics) of the drive brake unit from high temperatures. Preferably, the drive / brake unit is designed as a direct drive and does not include a wheel-integrated gearbox. The problem according to the invention is finally also solved by a vehicle comprising at least two drive brake units according to one of the above embodiments. Further details of the invention will become apparent from the description of the illustrated embodiments and the attached claims. The drawings show: Fig. 1 an isometric partial view of a first embodiment of a drive brake unit according to the invention, Fig. 2 a sectional view of the first embodiment according to Fig. 1, Fig. 3 an isometric partial view of a second embodiment of a drive brake unit according to the invention, Fig. 4 an isometric partial view of the second embodiment according to Fig. 3 with the friction brake housing open, and Fig. 5 a sectional view of the second embodiment according to Fig. 3 and Fig. 4. In the following detailed description of preferred embodiments, the same reference numerals denote essentially identical or identical parts in or on these embodiments. However, for better clarity of the invention, the preferred embodiments shown in the figures are not always drawn to scale. Figures 1 and 2 show a first embodiment of the drive brake unit 2 according to the invention, while Figures 3, 4 to 5 show a second embodiment of the drive brake unit 2 according to the invention. Unless explicitly stated otherwise, both embodiments are described below. The friction brake unit 1 comprises at least one brake actuator 3 with an actuation direction B (see in particular Fig. 2), which is part of a brake caliper 10 for actuating the friction brake unit 1 and generating a braking torque. The brake caliper 10 (see in particular Fig. 2 and Fig. 5) comprises brake pads 15 and a brake disc 16. The friction brake unit 1 comprises at least two components 4, 5 that can be electrically connected to a vehicle. One component is a brake pad wear indicator 4 as shown in Fig. 1 (also part of the second embodiment). The brake pad wear indicator 4 is designed here to detect wear in both brake pads 15 of the brake caliper 10. Another component is an electrically actuated parking brake device 5 which is integrated into the hydraulic brake actuator 3, as can be clearly seen in Fig. 2. As can be seen in Fig. 1, Fig. 3, the friction brake unit 1 in both embodiments comprises a housing cover 6 as part of the friction brake housing 8 with a common connection geometry 7 for the at least two components 4, 5 that can be electrically connected to a vehicle. As shown in Fig. 4, the housing cover 6 includes, on one side facing the friction brake unit 1, intermediate geometries 9 for at least two of the components 4, 5 that can be electrically connected to a vehicle, which can be connected to component terminals of components 4, 5 (this can also be the case in the first embodiment according to Fig. 1 and Fig. 2). The electrical leads from the intermediate geometries 9 are brought together in the housing cover 6 in the common connection geometry 7. In the first embodiment shown in Figures 1 and 2, the friction brake housing 8 of the friction brake unit 1 comprises an elastically deformable sealing element 13A, which allows elastic deformation of the friction brake housing 8 during actuation of the brake actuator 3. Here, the sealing element 13A is designed as an axially extendable housing bellows. Thus, the housing cover 6, together with the elastically deformable sealing element 13A, is movably arranged and can follow the actuation of the brake actuator 3 along the actuation direction B. In the second embodiment shown in Figures 3, 4 to 5, the friction brake housing 8 includes a connection sealing element 13B that seals the passage of a movable hydraulic connection 21 of the friction brake unit 1 extending from the friction brake housing 8. The connection sealing element 13B is designed to extend elastically when the movable hydraulic connection 21 moves relative to the friction brake housing 8 during actuation of the brake actuator 3. Figure 5 indicates a saddle movement direction S, which the hydraulic connection 21 follows. The connection sealing element 13B is designed as an annular bellows, as can be best seen in Figure 5. This allows the hydraulic connection 21 to move while simultaneously sealing the friction brake unit 1. In the second embodiment, the friction brake housing 8 also includes a circumferential seal 13C. This circumferential seal 13C is arranged in a circumferential groove of the housing cover 6 of the friction brake housing 8 (see Fig. 5). Figures 2 and 5 show a cross-sectional view of the drive brake unit 2 with integrated friction brake unit 1. The wheel-integrated electric motor is arranged with the friction brake unit 1 at least partially axially overlapping along a motor rotation axis. The friction brake housing 8 of the friction brake unit 1 is sealed to a stator component 17 of the wheel-integrated electric motor, thus essentially preventing brake dust from escaping the drive brake unit 2. The stator component 17 is, by way of example, a base plate 17 extending substantially in the radial direction. The base plate 17 also carries a drive stator 22 with windings or coils for generating an alternating magnetic field of the electric motor. A drive torque can thus be generated by the interaction of the alternating magnetic field of the drive stator 22 with the magnetic field of permanent magnets arranged on a drive rotor 11, 18. The base plate 17, an external drive rotor 18, and a rotor base 12 (see Fig. 2, Fig. 5) can essentially form a motor housing.The electric motor in question is a double-rotor radial flux electric motor, wherein an inner drive rotor 11 is arranged radially inside the drive stator 22. A wheel bearing 14 supports and connects the base plate 17, the drive rotor 11, 18 and the brake disc 16. The wheel bearing 14 is shown in simplified form in Fig. 2, Fig. 5 without subdivision into static and rotatable components. The drive brake unit 2 also includes a wheel-integrated inverter 19, which is configured to convert the vehicle's direct current into alternating current for the electric motor. The inverter 19 can be connected to the vehicle's direct current cables via inverter terminals 20. Reference symbol list: 1 Friction brake unit 2 Drive brake unit 3 Brake actuator 4 Brake pad wear indicator / component 5 Parking brake device / component 6 Housing cover 7 Connection geometry 8 Friction brake housing 9 Intermediate geometry 10 Brake caliper 11 Drive rotor / Inner drive rotor 12 Rotor base 13A Sealing element 13B Sealing element 13C Sealing element 14 Wheel bearing 15 Brake pad 16 Brake disc 17 Stator component / Base plate 18 Drive rotor / Outer drive rotor 19 Inverter 20 Inverter connection 21 Hydraulic connection 22 Drive stator B Actuation direction S Caliper movement direction QUOTES INCLUDED IN THE DESCRIPTION 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 KR 20230021347A

[0003]

Claims

Drive brake unit (2), comprising a friction brake unit (1) and a wheel-integrated electric motor for driving a vehicle, wherein the friction brake unit (1) comprises at least one brake actuator (3) for actuating the friction brake unit (1) and generating a braking torque, characterized in that the friction brake unit (1) comprises a friction brake housing (8), wherein the friction brake housing (8) is sealed against an environment with respect to the entry and exit of brake dust and fluids by means of at least one sealing element (13A, 13B, 13C). Drive brake unit (2) according to claim 1, characterized in that a friction brake housing (8) of the friction brake unit (1) comprises an elastically deformable sealing element (13A, 13B) which enables elastic deformation of the friction brake housing (8) during actuation of the brake actuator (3). Drive brake unit (2) according to claim 2, characterized in that a sealing element (13A) comprises a housing bellows to allow an elastic extension of the friction brake housing (8) parallel to the actuation direction (B) of the brake actuator (3). Drive brake unit (2) according to claim 2 or 3, characterized in that a friction brake housing (8) of the friction brake unit (1) comprises a connection sealing element (13B) which seals a passage of a movable hydraulic connection (21) of the friction brake unit (1) extending from the friction brake housing (8), wherein the connection sealing element (13B) is arranged to extend elastically in the event of a relative movement of the movable hydraulic connection (21) with respect to the friction brake housing (8) during actuation of the brake actuator (3). Drive brake unit (2) according to claim 4, characterized in that the connection sealing element (13B) is designed as an annular bellows around the movable hydraulic connection (21). Drive brake unit (2) according to one of the preceding claims, characterized in that the friction brake housing (8) comprises a housing cover (6), wherein a circumferential seal (13C) is arranged between the housing cover (6) and the remainder of the friction brake housing (8). Drive brake unit (2) according to one of the preceding claims, characterized in that the friction brake unit (1) comprises at least two components (4, 5) that can be electrically connected to a vehicle, wherein the friction brake housing (8) has a common connection geometry (7) for the at least two components (4, 5) that can be electrically connected to a vehicle. Drive brake unit (2) according to claim 7, characterized in that the connection geometry (7) is integrated in a housing cover (6) of the friction brake housing (8), wherein the housing cover is connected to a residual part of the friction brake housing (8) or a stator component (17) by means of a sealing element (13A) with housing bellows in a sealing manner in order to enable a displacement of the connection geometry (7) parallel to the actuation direction of the brake actuator (3) with the brake actuator (3). Drive brake unit (2) according to claim 7 or 8, characterized in that an electrically connectable component (4, 5) to a vehicle is an electrically actuated parking brake device (5). Drive brake unit (2) according to claims 7 to 9, characterized in that an electrically connectable component (4) to a vehicle is a brake pad wear indicator (4). Drive brake unit (2) according to claims 7 to 10, characterized in that intermediate geometries (9) for at least two of the components (4, 5) that can be electrically connected to a vehicle are arranged in a housing cover (6) of the friction brake housing (8) on a side facing the friction brake unit (1), which can be connected to component connections (11, 12) of the components (4, 5), wherein the electrical lines from the intermediate geometries (9, 10) in the housing cover (6) are brought together in the common connection geometry (7). Drive brake unit (2) according to one of the preceding claims, characterized in that the friction brake unit (1) is a disc brake with a brake caliper designed as a floating caliper. Drive brake unit (2) according to one of the preceding claims, characterized in that the wheel-integrated electric motor and the wheel-integrated friction brake unit (1) are arranged along the motor rotation axis (A) of the electric motor in a manner that is at least partially axially overlapping with the electric motor. Drive brake unit (2) according to one of the preceding claims, characterized in that the electric motor is a double rotor radial flux motor in which a drive stator (22) is arranged radially between an outer drive rotor (18) and an inner drive rotor (11), wherein the drive stator (22) comprises coils for generating a magnetic field. Drive brake unit (2) according to one of the preceding claims, characterized in that the drive brake unit (2) comprises a wheel-integrated inverter (19) which is configured to convert vehicle-side direct current into alternating current to the electric motor. Vehicle comprising at least two drive brake units (2) according to one of the preceding claims.

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