Friction brake with integration for a motor vehicle wheel hub drive

Abstract

The invention relates to a friction-type wheel brake (9) suitable and intended for wheel hub drive integration in a motor vehicle, in particular for a fluid-cooled electric wheel hub drive system (5), comprising a wheel brake rotor (11) and a wheel brake stator (10). For system decoupling and improved, simplified brake cooling, the invention defines that a wheel brake rotor (11) is designed to be passively cooled without fluid channels.

Description

The invention relates to a novel integrated friction brake comprising a brake rotor for cooperation with at least one friction lining and a brake stator, for an electric wheel hub drive comprising a drive rotor and a fluid-cooled arranged drive stator which is present substantially centrally in the interior of a vehicle wheel.DE 10 2010 008 230 A1 relates to a drive wheel having a wheel hub motor and a brake, which are cooled with a cooling fluid, wherein the cooling fluid used for cooling the wheel hub motor is conducted through at least one part of the brake. The brake may be understood as a disc brake, and it is also described that the circulating cooling liquid is guided through the brake caliper and / or through the brake disc. For this purpose, correspondingly branched coolant channels for common thermal management may be defined.DE 10 2021 121 502 A1 contains a wheel hub drive together with a brake device and a combined arrangement of a fluidic-circuit-guided cooling circuit in such a way that a first line section is configured to remove heat from the drive stator and a second line section is present which is configured to temperature-control the brake device.The branched-off circulation solution proposed in the known prior art appears complex and is perceived as less flexible to implement, which is also associated with the complex fluidic-branched strand guide+circulation cooling including sealed channel design.Accordingly, it is an object of the present invention to improve the availability and robustness of a wheel brake of the generic type as efficiently as possible and with the highest functional safety.The wheel brake, namely the drive-integrated brake, should furthermore be shown as easy to install and also maintain as possible, and yet decoupled. The mutual functional compatibility and integration that are necessary with heavy installation space compression is to be further improved. Mutual negative influence due to mechanical, thermal or other disturbances should be minimized as much as possible in order not to have to accept any negative feedback or loss of performance. At the same time, a highly compressed and durable wheel drive system which can also be implemented in a working part in a motor vehicle production is to be represented.The present invention avoids the problems of direct fluidic brake rotor cooling by providing an improved supply with a competitively suitable configuration by means of passively adapted brake rotor cooling. For example, according to the invention, an efficiently improved and fluid- and contactless defined decoupling of the brake heat between the rotatable wheel brake rotor and the drive motor stator arranged in a rotationally fixed and fluid-cooled manner is made possible. Other or further decouplings are proposed.The present invention thus offers a novel solution to overheating problems of friction brakes allocated close to the drive. The description of the invention is primarily made, by way of example, on the basis of drum brake integration. However, in principle and in a further alternative embodiment, it is entirely conceivable to transmit it to a disc brake arrangement instead of the drum brake arrangement without departing from a concreteized essence of the invention.The invention defines a contactless as well as fluid-free thermal connection / connector / coupling for transporting away the brake rotor from the brake by means of contactless, i.e. indirect, coupling to coolant or cooling body, i.e. coupling to a heat sink. This indirect connection may, however, not only relate to utilization of a liquid cooling system of the fluid-cooled wheel hub drive, but may involve other heat-exchanging means or media, such as, in particular by way of example, direct or indirect air cooling with a (electromotively driven) blower or passively parasitically as a result of vehicle movement and as a result of ambient air passing by.As a result, the invention enables a frictional energy of an encapsulated wheel brake, which frictional energy is converted into heat during friction braking, to be decoupled indirectly and transported away via a heat sink, cooling fluid, etc., which is discharged to ambient air, in particular by way of example via a heat exchanger downstream in the fluid circulation, or is set for other subsystems for energy conversion or utilization (brake heat pump for the purpose of thermal-electrical energy conversion, heating of a passenger compartment at low temperature or a temperature control of an electrical energy store).Since a conventional wheel hub drive housing / stator is usually stationary and fixedly installed on the vehicle side, but a brake rotor such as the brake drum rotates in contrast, a transmission path of convection (physical heat conduction) and the transmission path of heat radiation can be incorporated and used in thermal management with a contactless connector.As is schematically shown in the diagram, a significant increase in the surface area and the viewing area "A" between the stationary and rotating component is appropriate for increasing the transferred heat flow "P".A further design embodiment includes the following: A motor vehicle wheel 1 with tire 2 and rim 3 is mounted on a wheel hub 4 in conjunction with an electrical wheel hub drive 5 such that RNA can be rotated and electrically driven or regeneratively braked. The wheel hub drive 5 has a stator 6 and a rotor 7 and one or more electrical connections 8, and the motor vehicle wheel 1 which is arranged in such an electrically drivable manner and also such that it can be electrically regeneratively braked by the wheel hub drive 5 is also assigned a wheel brake 9 of the friction type for the purpose of providing service brake requests. The friction wheel brake 9 comprises at least one brake stator 10 mounted in a rotationally fixed manner, a brake rotor 11 mounted rotatably with the vehicle wheel 1 via the wheel hub 4, and at least one friction lining 12 arranged in a rotationally fixed manner and brake-actuatable by means of actuator 13 The friction lining 12 is consequently in friction cooperation with the brake rotor 11 as required (i.e. differentiated according to the case of actuation for the presentation of an electronically controlled service brake request or electronically controlled parking brake request).The electric service brake system of each vehicle wheel 1, which is integrated in principle from a plurality of partial brake systems or modules, is shown electrically and controllably by means of at least one electronic control unit ECU depending on the driver's intention or automatically. Microprocessor-controlled and / or automatic wheel brake control is possible. Each vehicle wheel 1 may be assigned an individual wheel brake control unit WCU for this purpose. An electric wheel brake control or WCU may wholly or partly integrate an electronic system of an electric wheel hub drive control. The wheel brake 9 can also integrate an electric parking brake EPB completely or at least partially in important parts (for example a MGU=motor gear unit) (combined electric wheel brake 9). An electronic brake control unit ECU, such as in particular a wheel brake control unit WCU, can integrate software, hardware, etc. for the electronic regulation of an electric parking brake EPB. It is understood that any regulation lecture within the scope of service brake control is perceived as required, efficiently and economically with mutual matching, synchronization or inclusion between the regenerative partial brake system of the wheel hub drive 5 and the friction brake 9. The wheel brake 9, such as in particular its actuator system, can be equipped with a sensor system S, namely in particular with an electric brake load measuring device S, for the purpose of regulation according to requirements.When the wheel brake 9 is integrated in the center of the wheel hub drive 5, there is a need for efficient brake waste heat management due to cooling. According to the invention, this is primarily done in a contactless, namely passively cooled, waste heat management. Nevertheless, it is not acceptable that brake waste heat from wheel brake components is passively coupled in a contactless manner, for example, into the peripheral cooling systems of other systems or components. For example, it is possible that brake waste heat of the friction brake is passively dissipated in a contactless manner into (cooled) components of a wheel hub drive, and wherein the relevant component of the wheel hub drive can of course also be configured to be fluidically cooled (wheel hub drive with a fluid cooling system). For the passive-contactless coupling of the heat, transfer means 19 can be formed. A heat conducting plate, a brake anchor plate, a special rib- or comb-like structure (arbitrary combinations of the above features are expressly possible) is suitable as the transmission means 19 by way of example, but not by way of limitation, so that brake waste heat of the friction brake 9 can be dissipated passively and at least partially into other or peripheral components or cooling systems. With thermal coupling that is designed to engage each other or engage each other in an alternating manner, particularly contactless and cooling ribs or comb-like manner, on the basis of the transmission structure 19 between the stator of the wheel hub drive 6RNA and the rotating brake rotor / brake drum 11, improved heat transmission takes place. Stator 6 or housing-side ribs can be supplied with coolant in particular by means of fluid channels inserted additionally and on the stator side and represent an increased cooling effect (lowering of "Tenv"), i.e. the heat transfer is additionally improved. Furthermore, the effectiveness or a heat transfer coefficient ("alpha") can be further improved by targeted attachment of flow-turbulence-enhanced element, for example, on a comb / rib surface 19 or in the cooling / flow space. Furthermore, for improvement, it may be useful to increase the emission coefficient ("epsilon"), for example, by technical thin coating / surface finishing of comb / coupling surface.Brake waste heat or brake cooling measures developed further according to the invention make it possible to further compress the installation spaces involved without the components adversely affecting one another.It is made possible to provide an encapsulation of the friction brake with high performance and brake availability, which additionally has a positive effect on particulate matter retention properties. Consequently, an implementation of approximately closed wheel houses or wheel rims is appropriate, in order for example to efficiently reduce a vehicle air resistance, i.e. drive energy requirement of the vehicle. It is possible to use the frictional heat energy inevitably generated during friction braking in another form, such as to convert it in an environmentally compatible manner by means of a heat pump, for example. For this purpose, a heated cooling liquid is also available for further use in other systems, for example. The invention is furthermore suitable not exclusively for motor vehicles but also for industrial brakes, elevators in buildings, or combined electric brake drives (e.g. robotics and / or automation technology).List of reference characters1 Motor vehicle wheel 2 Tyre 3 Rim 4 Wheel hub 5 Wheel hub drive 6 Stator of the wheel hub drive RNA 7 Rotor of the RNA (wheel hub drive) 8 Electrical connection of the RNA (wheel hub drive) 9 Wheel brake / friction brake 10 Brake stator 11 Brake rotor 12 Friction lining 13 Brake actuator 14 MMI - brake - human - machine - brake interface 15 MMI - RNA - human - machine - wheel hub drive interface 16 Heat exchanger 17 Coolant circulation line / ring line 18 Coolant circulation line / ring line 19 Indirect contactless transmission means / transmission structure / comb / rib 20 Coolant interface 21 Coolant interface Ax Axial direction = wheel rotation axis R Radial direction S Sensor - in particular brake load measurement deviceReferences included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedDE 10 2010 008 230 A1

[0002] DE 10 2021 121 502 A1

[0003]

Claims

Wheel brake (9) of the friction type with suitability and determination for wheel hub drive integration in a motor vehicle, in particular for a fluidically cooled electrical wheel hub drive system (5) comprising wheel brake rotor (11) and wheel brake stator (10), characterized in thatthe wheel brake rotor (11) is configured to be passively cooled without fluid channels.Wheel brake (9) according to Claim 1, characterized in that the wheel brake (9), or the components thereof, is substantially encapsulated on the basis of the wheel hub drive system (5).Wheel brake (9) according to one or more of the preceding claims, characterized in that the wheel brake (9) is inserted fully or partially independently mountable and / or removable in an interior of the wheel hub drive system (5).Wheel brake (9) according to one or more of the preceding claims, characterized in that the wheel brake (9) or wheel brake parts is grouped decoupled from the wheel hub drive system (5) as a separate wheel brake module, which is handled in particular in a single-piece bundle, or alternatively as a separate wheel brake assembly, which is defined in an exemplary manner in two pieces and comprises, for example, a wheel brake rotor assembly and a wheel brake stator assembly, or furthermore alternatively as a decoupled-defined and multi-piece-handled wheel brake (9), which is respectively integrated separately, independently and centrally decoupled in the wheel hub drive system.Wheel brake (9) according to one or more of the preceding claims, characterized in that a fluid-cooled electric wheel hub drive (5) is present, comprising a drive motor rotor (7) which can be coupled radially outwards R with respect to a central wheel rotational axis Ax and in a rotationally fixed manner to the motor vehicle wheel (1) and encloses the wheel brake (9) in the manner of a capsule, and having a drive motor stator (6) which can be placed in a rotationally fixed and fluid-cooled manner on a vehicle axle component, such as in particular on a pivot bearing, wherein the wheel brake (9) has the wheel brake rotor (11) in cooperation with a friction lining (12) which is mounted in a rotationally fixed and brake-actuatable manner with the wheel brake stator (10) and cooperates with at least one brake actuator (13), such as in particular with an expansion device.Wheel brake (9) according to one or more of the preceding claims, characterized in that the brake actuator (13) is designed electrically, in particular electromechanically, and has an associated electrical wheel brake control unit (WCU).Wheel brake (9) according to one or more of the preceding claims, characterized in that the wheel brake rotor (11) can introduce accumulated brake heat on the one hand into the wheel hub (4) and / or on the other hand into a pot base of a drive motor rotor (7).Wheel brake (9) according to one or more of the preceding claims, characterized in that at least one contactless coolant is provided, which allows the wheel brake rotor (11) to couple accumulated brake waste heat into a stator component (6, 10), which is preferably cooled in a fluidic manner, for the purpose of cooling.Wheel brake (9) according to one or more of the preceding claims, characterized in that the drive motor rotor (7) and the wheel brake rotor (11) are offset one inside the other in a mutually stacked manner with a difference in diameter from radially outside to radially inside, and are arranged substantially pot-shaped in each case with a pot base and with in each case one pot wall coaxially one inside the other centered with respect to the wheel rotation axis Ax.Wheel brake (9) according to one or more of the preceding claims, characterized in that the wheel brake rotor (11) is separated from the drive motor rotor (7) by defined spacing, preferably by air gaps, for the purpose of decoupling.Wheel brake (9) according to one or more of the preceding claims, characterized in that, for the purpose of decoupled coaxial centering, the wheel brake rotor (11) is assigned a snug fit on the wheel hub.Wheel brake according to one or more of the preceding claims, characterized in that, for the purpose of decoupled coaxial centering, the drive motor rotor (7) is assigned a snug fit on the wheel hub (4).Wheel brake (9) according to one or more of the preceding claims, characterized in that a plurality of snug fits are provided spaced apart from one another in the region of the wheel hub (4) with axial spacing.Wheel brake (9) according to one or more of the preceding claims, characterized in that the fits of the wheel hub (4) are formed as sections of different external diameters, which are designed differently in a defined manner with respect to one another and on which the respective rotors are seated with their through-hole diameters defined individually and differently adapted to one another.Wheel brake (9) according to one or more of the preceding claims, characterized in that the wheel brake (9) is designed as a disc brake system with a brake disc as a wheel brake rotor (11) or as a drum brake system with a brake drum as a wheel brake rotor (11).Wheel brake (9) according to one or more of the preceding claims, characterized in that the wheel brake (9) comprises an integrated electric parking brake EPB.Wheel brake (9) according to Claim 15, characterized in that the electric parking brake EPB defines an electrically normally defined, such as in particular friction-based, parking brake actuator lock or a switchable, namely electrically normally defined, parking brake lock.Wheel brake (9) according to one or more of the preceding claims, characterized in that a preferably electrical brake actuator (13), for the purpose of electronic friction brake control, enables a brake load detection, such as in particular has an electrical brake load measuring device S.

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