Electromechanical system for installation in the wheel hub of a vehicle

Abstract

The invention relates to an electromechanical system (1) for stationary arrangement in a central cavity (43a) of a wheel hub (43) of a vehicle (61), wherein the electromechanical system (1) comprises: a generator (11) for generating electric current, an electric motor (23) for actuating an actuator (2), the actuator (2), and a storage system (20) for storing electrical energy, is characterized in that the actuator (2) is linearly movable along a longitudinal axis (LA) of the electromechanical system (1), that a coupling device (24) couples the motor (23) to a radially inner part (2b) of the actuator (2), and that the storage system (20) has several storage elements (21) which are arranged radially outside around the longitudinal axis (LA) and around the motor (23) and are at least partially spaced apart from one another in a circumferential direction (UR).and that a radially outer part (2a) of the actuator (2) is formed radially beyond the storage elements (21), wherein connecting elements (2c) of the actuator (2) rigidly connect the radially inner part (2b) and the radially outer part (2a) to each other and extend between the storage elements (21). With the electromechanical system, a high operational readiness can be achieved in a compact space.

Description

The invention relates to an electromechanical system for stationary arrangement in a central cavity of a wheel hub of a vehicle, wherein the electromechanical system comprises: a generator for generating electric current, an electric motor for actuating an actuator, the actuator, and a storage system for storing electrical energy. Such an electromechanical system has been disclosed by EP 3 530 482 A1 . Many types of vehicles have wheels that allow them to roll along the ground and thus move about. For numerous applications, it is advantageous or desirable to install functions on the wheels, which rotate relative to the vehicle and require electrical energy. These functions can include monitoring functions. For example, it is often desirable to obtain information about the wheel's current rotational speed, which can be achieved with electrical sensors mounted on the wheel. However, transmitting electrical current from the vehicle to the rotating wheels is difficult, especially at high wheel speeds. While sliding contacts are possible, they wear out easily, and integrating the sliding contacts and associated wiring into the vehicle is very complex. Therefore, it has become common practice, particularly for wheel sensors, to power them with a battery that is mounted on the wheel along with the sensor. The battery is replaced when depleted, typically during routine maintenance in a workshop. Using batteries to power a rotating vehicle wheel and replacing them when depleted is particularly advantageous when the application's energy consumption is relatively low, meaning replacement is only required infrequently (e.g., every few years). In some applications, it is desirable to move components on the rotating wheel while it is in motion. For this purpose, an electric motor and a motor-driven actuator are typically used. For example, it has become known to install a rim cover over the wheel rim. With the rim cover closed, a particularly low airflow resistance of the wheel is achieved. However, the closed rim cover also conceals openings in the rim through which cooling air can reach the vehicle's brakes at the wheel hub. If the brakes were to overheat (for example, when driving downhill), the rim cover can then be opened with a motor-driven actuator to allow more cooling air to reach the brakes. From EP 3 530 482 A1, it is known to equip a vehicle wheel with an electromechanical system that is installed in the wheel hub. This system comprises a rechargeable battery, a generator with an eccentric weight, and a circuit board. Electrical loads to be powered include a motor for actuating covers that close the gaps between the radial fins of a light alloy wheel, and sensors for measuring rotational speed or temperature. The battery is a button cell and is located at the front end of the electromechanical system, where it projects into the hub. This well-known electromechanical system can be used to establish a self-sufficient power supply independent of the vehicle, which can also be used to motorize the rim cover of a vehicle wheel. However, no further details are given about the motor's arrangement. An electromechanical system in the central cavity of a wheel hub must accommodate a significant number of components in a small space, while ensuring a high level of operational readiness. The electromechanical system is located in the central cavity of the wheel hub, close to the vehicle's brakes. A failure of the electromechanical system can be caused, in particular, by the vehicle's brakes overheating after prolonged braking maneuvers, and this heat penetrating to the electromechanical system. From DE 10 2011 113 021 A1 it is known that an electric actuator with stator and movable rotor can be arranged in the central cavity of a wheel hub of a vehicle in order to efficiently realize rotary and translational movements. Object of the invention The object of the invention is to present an electromechanical system of the type mentioned above, with which a high operational readiness can be achieved in a compact space. Description of the invention This problem is solved according to the invention by an electromechanical system of the type mentioned at the outset, characterized in that the actuator is linearly movable along a longitudinal axis of the electromechanical system, that a coupling device couples the motor to a radially inner part of the actuator, that the storage system has several storage elements which are arranged radially outside around the longitudinal axis and around the motor and are at least partially spaced apart from each other in a circumferential direction, and that a radially outer part of the actuator is formed radially beyond the storage elements, wherein connecting elements of the actuator rigidly connect the radially inner part and the radially outer part to each other and extend between the storage elements. The invention provides for arranging the motor of the electromechanical system in a radially inner, axially close region (with respect to the longitudinal axis of the electromechanical system). The storage elements of the rechargeable electrical energy storage system are arranged around the motor; the individual storage elements can be, for example, rechargeable batteries or capacitors. This arrangement directs heat coming from the radial outer edges (typically originating from a wall of the wheel hub radially surrounding the electromechanical system) first onto the storage elements located further out radially. These storage elements can shield against heat radiation coming from the radial outer edges and also absorb and store heat energy coming from the radial outer edges, thus keeping this heat energy away from the motor. According to the inventors' observations, typical energy storage devices such as batteries or capacitors can withstand higher temperatures much better than an electric motor. In particular, the energy storage devices can remain operational even at higher temperatures, unlike a motor, which may no longer function reliably at higher temperatures or may even have to be switched off to prevent damage. In the case of chemically acting energy storage devices (such as batteries), an increased temperature can even slightly improve their performance. The arrangement of the storage elements according to the invention, radially outside, beyond the motor and around the motor, thus allows a high (long) operational readiness to be maintained when the electromechanical system is heated from the radial outside. To enable the use of the actuator radially outward on the electromechanical system despite the arrangement of the storage elements around the motor, the actuator is constructed with a radially inner part and a radially outer part. Mechanical coupling to the radially inner motor is easily achieved via the radially inner part. The movement of the inner part can be transmitted to the outer part of the actuator using the connecting elements according to the invention, which extend outward to the radially outer part. These connecting elements pass through (azimuthal) gaps between the storage elements. The gaps are sufficiently extended in the axial direction so that the connecting elements have enough space in all desired travel positions of the actuator. Typically, the storage elements are aligned parallel to the longitudinal axis for this purpose. Typically, the actuator operates a (one-piece or multi-piece) wheel rim cover. The rim cover is mechanically coupled to the outer part of the actuator; this can be, for example, a rigid coupling (typically for a one-piece rim cover) or a pivot coupling (typically for a multi-piece rim cover). The coupling between the outer part of the actuator and the rim cover can be achieved, in particular, via radially outward-projecting tabs on the outer part of the actuator. The electromechanical system also typically includes one or more sensors that monitor the current state of the vehicle wheel. The sensor data is typically transmitted wirelessly to an electronic system in the vehicle, possibly after preprocessing in an evaluation unit within the electromechanical system. The sensors are typically located on a main circuit board of the electromechanical system. The longitudinal axis corresponds to a rotational axis of the wheel hub in the assembled state of the electromechanical system. In its assembled state, the electromechanical system is inserted with its front end into the central cavity of the wheel hub; the rear end of the electromechanical system typically protrudes slightly from the cavity. The electromechanical system is fixed in place within the wheel hub (i.e., it rotates with the wheel hub). For this purpose, the electromechanical system is preferably attached to the vehicle's wheel hub and / or the vehicle wheel in a suitable manner. Typically, the electromechanical system is attached directly to the wheel hub, for example, by bolting a housing of the electromechanical system to the wheel hub. The electromechanical system can also be referred to as an electromechanical hub cap. The electromechanical system can be used with standard wheels without requiring any complex modifications. Preferably, the electromechanical system is mounted to the vehicle's wheel hub. Thanks to the generator and energy storage system, the electromechanical system is energy self-sufficient. The generator supplies electrical energy (depending on the operating state) both directly to the consumers of the electromechanical system (e.g., the actuator motor and circuits for controlling the system) and to the energy storage system (for later use by the consumers). The electromechanical system does not require a cable connection to the vehicle, neither for power supply nor for data exchange; data exchange can be carried out wirelessly using energy from the generator and the energy storage system. Depending on the operating state, the generator charges the energy storage system and / or supplies power to the consumers of the electromechanical system, in particular the motor, electronic circuits and evaluation units, sensors, and communication equipment. If the generator needs to be switched off during operation, e.g.,Because the temperature at the generator becomes too high, the other consumers or a selected part of them can continue to be supplied with electrical energy from the storage system. In summary, the electromechanical system can be designed to be resistant to environmental influences, especially heat radiation from the brakes. The system can be built in a compact space and is resistant to vibrations and external shocks. It can be mounted on the vehicle's wheel hub, eliminating the need for any modifications to the vehicle's wheels. By positioning the system on the wheel hub or its axis of rotation, centrifugal forces acting on the electromechanical system are minimized. The individual mechanical and electrical components of the electromechanical system (with the exception of an unbalanced component of the generator) are preferably arranged symmetrically to the wheel's axis of rotation, thus minimizing the imbalance of the electromechanical system (and the vehicle wheel as a whole). A vehicle on which the invention can be used is, for example, a car (in particular a passenger car), a transport vehicle (in particular a truck), a construction vehicle (in particular an excavator or wheel loader), a military vehicle or a rail vehicle. Preferred embodiments of the invention In a preferred embodiment of the electromechanical system according to the invention, the coupling device comprises a spindle rotatably mounted about the longitudinal axis and driven by the motor. The spindle has an external thread, the actuator has an internal thread on its radially inner part which is screwed onto the external thread of the spindle, and the actuator is mounted non-rotatably with respect to the longitudinal axis. The spindle allows for the simple conversion of a rotary motion of a motor shaft (or a transmission shaft of an intermediate gearbox) into a linear traversing motion of the actuator. The spindle can, in particular, be cup-shaped and radially surround a gearbox and / or the motor. A preferred embodiment includes a coupling device comprising a gearbox that reduces the rotation of a motor shaft to the spindle. This allows for more precise positioning of the actuator (or a rim cover), and the motor requires less power to actuate the actuator. The spindle can be cup-shaped and arranged radially around the gearbox. A preferred embodiment features a rim cover for a vehicle wheel mounted on the wheel hub coupled to the radially outer part of the actuator. This allows the rim cover to be switched between a closed state (with low airflow resistance of the wheel) and an open state (with improved ventilation and thus better cooling of the vehicle wheel, the wheel hub, the brakes on the vehicle wheel, and / or the electromechanical system). Intermediate positions (with medium cooling and medium air resistance, depending on the position) are also possible within the scope of this embodiment. Actuation of the rim cover with the electromechanical system according to the invention is particularly reliable. An advantageous embodiment provides that the electromechanical system has a front end, which allows the electromechanical system to be inserted into the cavity of the wheel hub, and a rear end opposite it along the longitudinal axis. Along the longitudinal axis from the front end to the rear end, a sequence of components of the electromechanical system is arranged as follows: generator, coupling device, and motor. The front end is typically heated more by the vehicle wheel's brakes than the rear end. Accordingly, the motor is protected from heat input from the front end by the generator and the coupling device. If the generator has to be deactivated due to heating of the front end, this does not initially affect the operational readiness of the motor and the actuator, since electrical energy continues to be available from the storage system.When the vehicle is stationary, the generator is automatically deactivated; this is advantageous because the highest temperatures typically occur when the vehicle is stationary, immediately after heavy braking. The transmission, which is the next component to be heated after the generator, is comparatively insensitive to heat. The motor, which operates the wheel flaps and is located furthest from the front and therefore in the coolest area, is the component listed, and it requires a high level of operational readiness. A further development of this embodiment is also advantageous, in which the electromechanical system additionally includes an intermediate board and a main board, and in which the sequence of components of the electromechanical system is arranged along the longitudinal axis from the front end to the rear end as follows: generator, intermediate board, coupling device, motor, main board. The intermediate board, which primarily serves for electrical connection, is relatively insensitive to heat and can therefore be placed near the front end. The main board, on which typically many temperature-sensitive electronic components (e.g., processors, sensors) are located, is arranged near the rear end, which remains the coldest.The memory elements are located axially in the area of ​​the motor and usually also in the area of ​​the coupling device; the mainboard is therefore typically at least partially axially shielded by the memory elements. This ensures high (long) operational readiness, even when heated from the front end. A mainboard positioned near the rear end also improves the transmission performance of a first communication unit and / or a second communication unit (see below) on the mainboard. In an advantageous embodiment, the generator and the motor are identical in construction. This saves costs in the manufacture of the electromechanical system (economies of scale) and reduces the number of different components required, thus simplifying logistics. A particularly preferred embodiment is one in which the electromechanical system comprises a sensor system, wherein the sensor system is configured to measure linear movements of the electromechanical system with respect to at least a first local axis of motion and a second local axis of motion, which are linearly independent, as well as angular movements of the electromechanical system with respect to at least a first local axis of rotation and a second local axis of rotation, which are linearly independent of each other. The sensor system measures the position, orientation, and movement of the corresponding vehicle wheel while driving. This allows for the acquisition of numerous pieces of information (possibly in conjunction with other electromechanical systems on other vehicle wheels) that are relevant to the vehicle's operation. This information can be used, for example, to adjust vehicle characteristics and / or control the vehicle, such as in an Electronic Stability Program (ESP), an Anti-lock Braking System (ABS), or an adaptive chassis control system. In particular, vertical wheel movement can be determined. This allows conclusions to be drawn about the road surface structure (asphalt, concrete, gravel, unpaved, etc.), the road surface condition (slippery, wet, etc.), and / or the tire grip. Furthermore, the wheel's rotational speed can be determined ("horizontal wheel movement"). Additionally, the sensor system can detect wheel vibration. Alternatively or additionally, a separate vibration sensor can be provided for vibration measurement. Further sensors can also be integrated into the electromechanical system, typically on the main circuit board. The sensor system measures at least two linear movements and two rotational movements, and accordingly generates 4D motion information. The sensor system moves together with the electromechanical system, i.e., together with the wheel to whose hub the electromechanical system is attached. The sensor system is typically located on a main circuit board of the electromechanical system. All local axes of motion about which linear movements are measured preferably form an orthogonal system. All local axes of rotation about which angular movements are measured preferably form an orthogonal system. If present, all local magnetic field measurement axes also preferably form an orthogonal system (see below). Typically, the measured local axes of motion are chosen to be identical to the measured local rotation axes, and optionally also identical to the measured local magnetic field measurement axes. The local axes of the electromechanical system (these are local axes of motion, local axes of rotation, local axes of magnetic field measurement) move with the electromechanical system. Through a suitable coordinate transformation, the measurement data for the local axes of the electromechanical system can be converted into the axes of the vehicle to whose wheel hub the electromechanical system is attached. The coordinate transformation can be performed, in particular, in an evaluation unit of the electromechanical system, or alternatively in an electronic system of the vehicle. The vehicle's coordinate axes are fixed within the vehicle and therefore move together with the entire vehicle. Typically, the vehicle's coordinate axes, to which the measurement data are converted, are chosen as follows: - x-axis, which is the (horizontal) forward direction of travel of the vehicle; - y-axis, which is the horizontal direction perpendicular to the forward direction of travel; and - z-axis, which is the vertical direction perpendicular to the forward direction of travel. The x-axis as the axis of rotation corresponds to the roll axis, the y-axis as the axis of rotation corresponds to the pitch axis, and the z-axis as the axis of rotation corresponds to the yaw axis. Linear (straight-line) movements are typically measured using accelerometers. The angular movements are typically measured using a gyroscope. Magnetic field strengths are typically measured using the Hall effect or magnetoresistive (MR) sensors. A preferred further embodiment of this system is configured to measure linear movements of the electromechanical system with respect to a third local axis of motion, wherein all local axes of motion are linearly independent, as well as angular movements of the electromechanical system with respect to a third local axis of rotation, wherein all local axes of rotation are linearly independent. In this case, the sensor system measures a total of three linear movements and three rotational movements, and accordingly generates 6D motion information. This allows for even more precise statements about the position, orientation, and movement in space of the associated vehicle wheel during driving. A further development is also preferred in which the sensor system is configured to measure the magnetic field strength at a measurement point in the electromechanical system with respect to at least one first local magnetic field measurement direction and a second local magnetic field measurement direction that are linearly independent. By measuring the magnetic field strength, the Earth's magnetic field can be measured, and in particular, the orientation of the electromechanical system or the associated vehicle wheel relative to the Earth's magnetic field can be determined. A sub-variant of the above further development provides that the sensor system is still configured to measure the magnetic field strength at the measurement point in the electromechanical system with respect to a third local magnetic field measurement direction, where all local magnetic field measurement directions are linearly independent. This allows for even more precise measurement of the Earth's magnetic field and determination of the orientation of the electromechanical system within the Earth's magnetic field. In a preferred embodiment, a local axis of motion and a local axis of rotation are chosen as the longitudinal axis of the electromechanical system, which also corresponds to a rotational axis of the wheel hub in the assembled state of the electromechanical system, in particular where a local magnetic field measurement axis is also chosen as the longitudinal axis of the electromechanical system. The rotational speed (or rotational speed) of the associated wheel can be directly determined via the local axis of rotation along the rotational axis of the wheel hub. An instantaneous lateral slippage motion can be easily detected via the local axis of motion along the rotational axis. A further advantage is an embodiment in which the generator comprises a stator fixed within the electromechanical system and a rotor rotatable relative to the stator, the rotor being designed with an imbalance. Due to its weight, the imbalance always remains in a lower position relative to the direction of gravity, even when the wheel rotates. The stator, fixed to the electromechanical system, rotates with the wheel when it rotates. This causes the rotor to move relative to the stator, which can be used to generate electrical energy. The axis of rotation of the rotor generally lies along the longitudinal axis of the electromechanical system and along the axis of rotation of the wheel. Apart from the imbalance, the electromechanical system is preferably designed to be approximately rotationally symmetrical with respect to the longitudinal axis around which the wheel hub rotates in the assembled state.This evens out the forces on the electromechanical system caused by centrifugal force when the vehicle wheel rotates, and in particular minimizes asymmetrical rotating forces perpendicular to the longitudinal axis. This reduces the mechanical stress on the electromechanical system. Specifically, energy storage elements of the electromechanical system can be arranged individually or in groups at uniform angular intervals and with the same radius around the longitudinal axis. For example, the energy storage elements can be arranged in pairs opposite each other (i.e., offset by 180°) and with the same radius relative to the longitudinal axis. A preferred further development of the above embodiment provides that the rotor is rotatably mounted within the stator, that one or more permanent magnets are formed on the rotor, and that one or more electromagnetic coils are formed on the stator. Due to the arrangement of the electromagnetic coils on the stator, which is stationary within the electromechanical system, no sliding contacts (such as brushes) are required for current transmission to the (remaining) electromechanical system. This improves wear resistance and is particularly low-maintenance, durable, reliable, and energy-efficient. The arrangement of the rotor within the stator provides for the electromagnetic The coils surrounding the rotor provide ample usable space. The permanent magnets mounted on the rotor are located axially in the area of ​​the coils, and the imbalance is typically located axially next to the coils. Overall, this design allows for a very compact and efficient construction. In an advantageous embodiment, the electromechanical system comprises an intermediate board and a main board, wherein electrical connections are provided between the intermediate board and the storage system, between the storage system and the main board, and between the intermediate board and the main board, in particular wherein further electrical connections are provided between the generator and the intermediate board, and / or between the main board and the motor. The intermediate board and the main board allow for the simple establishment of electrical connections (for power supply and / or control signals and / or measurement signals) to the essential components of the electromechanical system. Typically, the energy storage system is located between the intermediate board and the main board, and the individual storage elements of the system can be aligned with their electrical poles on the intermediate board and the main board, and easily contacted from these two boards. Typically, both boards are oriented perpendicular to the longitudinal axis, and the storage elements are oriented along the longitudinal axis. In particular, the intermediate board allows for the accumulation of the ground potentials of the generator and the energy storage system. From the intermediate board, the accumulated ground potential and other electronic signals can be transmitted to the main board.The mainboard generally houses electronic components such as processors, control units, evaluation units, sensors, and communication devices. The motor is typically connected to the mainboard. A preferred embodiment features all electrical connections of the electromechanical system between the generator, the intermediate board, the storage system, the main board, and the motor made using spring-loaded contact pins and / or rigid connecting pins. These electrical connections achieve particularly high mechanical rigidity and robustness; the spring-loaded contact pins and rigid connecting pins remain dimensionally stable even during rapid rotation of the electromechanical system and exhibit little to no wear. Vibrations also have little effect on the spring-loaded contact pins and rigid connecting pins. In contrast, flexible cable connections could easily fatigue and break due to centrifugal forces, especially those of varying intensity, or vibrations.Note that electrical connections on circuit boards are typically established via conductive traces (local conductive coatings, e.g., made of copper) applied to the board, which also retain their shape. No further electrical connections are generally required. In a preferred embodiment of the electromechanical system, which is configured with an intermediate board and a main board and whose electrical connections between the generator, intermediate board, storage system, main board, and motor are exclusively provided by spring-loaded contact pins and / or rigid connecting pins, it is provided that spring-loaded contact pins establish the electrical connections between the intermediate board and the storage system, and between the storage system and the main board, in particular wherein spring-loaded contact pins further establish the electrical connections between a generator board of the generator and the intermediate board, and / or between a motor board of the motor and the main board. A spring-loaded contact pin can be compressed against the force of a spring along its longitudinal direction, thereby establishing an electrical connection between its axial ends at each extension length.The spring-loaded contact pins facilitate the assembly of the electromechanical system and simultaneously establish a robust and reliable electrical connection, even under centrifugal forces. In particular, the storage elements can be easily inserted between the already rigidly connected intermediate board and the main board. Similarly, the generator can be easily mounted on the intermediate board and electrically connected, or the motor can be easily mounted on the main board and electrically connected (or vice versa). An advantageous embodiment comprises several spring-loaded contact pins for establishing electrical connections. A spring-loaded contact pin can be compressed against the force of a spring along its longitudinal direction, thereby establishing an electrical connection between its axial ends at each extension length. The spring-loaded contact pins are essentially rigid; only the pin held in the sleeve is movable in the longitudinal direction. The spring-loaded contact pins exhibit high resistance to heat, shock, and vibration. Furthermore, the spring-loaded contact pins facilitate the assembly of the electromechanical system. A robust and reliable electrical connection is established, even under centrifugal forces. A particularly preferred embodiment includes a first communication device configured for wireless communication with an electronic system of the vehicle, especially wherein the first communication device is configured for wireless communication using the BLE (Bluetooth Low Energy) standard. The first communication device allows, in particular, the transmission of measurement data or information derived from measurement data from the electromechanical system to the electronic system of the vehicle, or the transmission of control information from the electronic system of the vehicle to the electromechanical system. Wireless communication eliminates the need for a cable connection, and mounting the electromechanical system on the vehicle is particularly simple.BLE enables particularly low energy consumption; in addition, it allows for control of power consumption according to vehicle state (power saving states) while simultaneously ensuring reliable data communication to the vehicle (despite rotation of the electromechanical system) and rapid re-establishment of the connection (fast so-called re-pairing). A further advantage is an embodiment in which the electromechanical system has a second communication device configured for wireless communication with one or more external sensors, in particular wherein the second communication device is configured for wireless communication via an RF or NFC connection, and in particular wherein the second communication device is also configured for wireless power transmission to the one or more external sensors as passive external sensors. The external sensors are arranged remotely from the electromechanical system. The second communication device can be used to read external sensors, which are typically also arranged on the vehicle wheel, for example, a sensor for measuring tire pressure.If wireless power transfer to the external sensors is set up, the external sensor does not require its own power supply, making the second sensor particularly simple and easy to maintain. In an advantageous embodiment, the electromechanical system includes an evaluation unit for analyzing measurement data from sensors within the electromechanical system and / or from external sensors. This analysis allows for the extraction of particularly relevant information from the measurement data for driving operation and vehicle control. This information can be used within the electromechanical system itself (e.g., temperature information for energy management) or transmitted to and used by an electronic system of the vehicle (e.g., for chassis tuning or an ESP program). Typically, this particularly relevant information requires less storage space and / or data transmission capacity than the underlying measurement data, or is easier to process further.The evaluation unit (also called the evaluation device) can convert measurement data (usually voltage or current values) into physical quantities (e.g., temperature or speed) and, if necessary, further process the measurement data or calculated physical quantities according to a program, for example, by comparing them with threshold values. Often, the evaluation unit is connected to or integrated with a control unit (for example, for energy management or cooling management), and the control unit then also generates control commands, for example, for activating or deactivating components, or for opening and closing a wheel cover. The evaluation unit (and, if applicable, the control unit) is typically located on the main circuit board. In an advantageous embodiment, the electromechanical system has at least one temperature sensor. The temperature sensor can detect whether the electromechanical system, or a component thereof, is operational with regard to its temperature. If necessary, the temperature information can be used to determine whether the affected component needs to be switched off or can be switched on again, or whether cooling measures (e.g., opening a wheel cover) need to be taken or can be discontinued. A preferred embodiment includes several temperature sensors, each measuring a temperature at a different location within the electromechanical system, particularly where at least one temperature sensor is arranged on the generator, the motor, the storage system, and a main circuit board of the electromechanical system. Alternatively, temperature sensors can also be provided on the generator, the motor, and the main circuit board. By using multiple temperature sensors at different locations, it is possible to determine for individual components of the electromechanical system whether they are operational or not, and accordingly, further control of the individual components (switching on or off) can be precisely tailored to the current operating situation. For example, if only the generator overheats, the electromechanical system can continue operating with the generator switched off, and energy supplied solely from the storage system as long as sufficient stored electrical energy remains. If the motor is at risk of overheating, cooling measures should be taken immediately (in particular, opening the wheel cover) before such measures (e.g., opening the wheel cover) are no longer possible. If the mainboard overheats, cooling measures should be taken, and the electromechanical system should be switched off to prevent incorrect sensor readings and measurements, and also to protect the components on the mainboard.Each component can be assigned its own first temperature threshold, above which the component can no longer operate reliably, and / or a second temperature threshold, above which the component would be irreversibly damaged. These temperature thresholds can then be taken into account in the cooling management. A further advantage is an embodiment in which the electromechanical system comprises one or more pressure sensors for measuring pressure in the vicinity of the electromechanical system, in particular wherein the one or more pressure sensors can be used to measure air resistance. The result of the pressure measurement can be used for vehicle control and / or for controlling the wheel covers. A further preferred embodiment comprises at least one lighting device which is supplied with electrical energy by means of the generator and / or the storage system, in particular wherein the at least one lighting device has one or more of the following functionalities: direction indicator, warning light, emergency light, position light, decorative light. The lighting device can generate light on the electromechanical system to make the lighting device itself more visible or to illuminate the surroundings. The light source is preferably an LED or an LED system. The lighting system is typically activated and / or deactivated via control commands from the vehicle's electronic system; however, it can also be activated and / or deactivated based on its own measurement data from the electromechanical system. For example, warning or emergency lighting can be activated after detecting acceleration exceeding a threshold that indicates a crash. Warning lighting can also be activated during hard braking, which is readily detectable by sensors within the electromechanical system itself. Emergency lighting from the electromechanical system can also be used if the vehicle's electrical system has failed, for example, if the vehicle is stranded on the roadside after a breakdown or rollover. Decorative lighting can, for example, display a desired brand logo of the vehicle manufacturer. An advantageous embodiment also includes at least one magnetically actuated switch with which the electromechanical system can be fully and / or partially activated and deactivated from outside its housing. The magnetically actuated switch (also called a magnetic switch) is typically actuated in a workshop. The magnetic switch is located within the housing of the electromechanical system and requires no openings in the housing through which dirt could penetrate; it is sufficient to appropriately bring an external magnet (for example, by rotating a magnet) near or past a specific location on the housing, which is typically marked for this purpose.For example, when vehicle wheels are stored seasonally, the electromechanical system can be deactivated via the magnetic switch, and when the vehicle wheels are remounted, it is reactivated using the magnetic switch. A preferred embodiment also includes an energy control device for managing electrical energy consumption, which can activate and deactivate components and / or functions of components of the electromechanical system. This allows the electromechanical system to be used particularly efficiently and / or its operational readiness to be increased. Unnecessary discharge of the storage system is avoided, or energy consumption is limited to a few particularly important functions when the storage level is low, possibly in stages. For example, the energy control device can provide for the temporary partial or complete shutdown of the first communication unit (power saving modes in BLE) as needed, such as switching off the transceiver during communication breaks.Components, particularly communication devices, can be deactivated, especially during extended periods of vehicle inactivity ("parking"). Depending on the energy supply and / or generator output, shorter or longer data transmission intervals for communication units can be implemented. Furthermore, temperature- and speed-dependent control of the actuator can be provided. The vehicle's electronic system can activate a sleep mode for the electromechanical system via a transmitted control command (e.g., when the vehicle is parked), during which the electromechanical system is largely deactivated. Ending the sleep state can also be initiated by an external command from the vehicle's electronic system, if desired. However, it is preferable for the electromechanical system itself to initiate the (necessary) end of the sleep state, for example, when it detects wheel movement. A particularly preferred embodiment is one in which the energy control device is configured such that: - when a first threshold of currently stored electrical energy in the storage system is undershot, one or more components and / or functions of components are deactivated; and / or - when a second threshold of instantaneous generator power is exceeded, one or more deactivated components or functions of components are reactivated. When the first threshold is undershot, the remaining energy can be reserved for particularly important remaining components or functions by deactivating components or functions. When the second threshold is exceeded, it is evident that (presumably) sufficient new energy is available again to enable the reactivation of components or functions.Alternatively or additionally, it can be provided that the electromechanical system can be put into an energy-saving mode (sleep mode) via an external command (e.g., from an electronic control unit of the vehicle), in which one or more components and / or functions of components are deactivated. If the second threshold is exceeded, the one or more deactivated components or functions of components can be reactivated. In an advantageous embodiment, the electromechanical system has a housing with an external thread for screwing into the vehicle's wheel hub. The external thread on the housing allows for easy positioning and fastening of the electromechanical system in the wheel hub. If desired, the screw-in connection can be secured, for example, with a lock nut also located on the external thread, which is tightened against an upper stop of the wheel hub. A further preferred embodiment provides that the storage system comprises rechargeable batteries and / or high-capacity capacitors, in particular electrolytic capacitors. Rechargeable batteries allow a large amount of energy to be stored in a small space, even for extended periods; elongated batteries with opposing terminals at their ends, for example, rechargeable AA batteries, are preferred. Capacitors enable particularly fast charging and discharging, allowing for a particularly high number of charge cycles. A high-capacity capacitor for the invention typically has a capacitance of at least 100 µF, often at least 0.1 F, preferably at least 1 F, and most preferably at least 10 F. In particular, so-called supercapacitors can be used. A further preferred embodiment provides that the electromechanical system has a housing which has a longitudinal wall extending at least substantially along the longitudinal axis, in which at least one access point for the actuator is provided, that in the area of ​​each access point in the longitudinal wall an outer wall part and an inner wall part are provided which: - extend parallel to the longitudinal axis, - but are spaced apart from each other in the transverse direction perpendicular to the longitudinal axis, - are at least partially offset from each other along the longitudinal axis, so that an inner free end of the inner wall part and an outer free end of the outer wall part are opposite each other in the area of ​​the access point, and that the actuator has at each access point: - a central section which extends along the longitudinal axis and is arranged in the transverse direction between the inner wall part and the outer wall part.- an inner collar formed at one end of the central section, which faces away from the inner free end, and extending inwards in a transverse direction over the inner free end, and - an outer collar formed at one end of the central section, which faces away from the outer free end, and extending outwards in a transverse direction over the outer free end. With this embodiment, the actuator can easily extend outwards through the housing, thus effecting movement (e.g., of a rim cover) outside the housing, while simultaneously largely covering the penetration point and thus protecting the interior of the housing from contamination. During the actuator's movement, its central section travels in front of the inner wall section and behind the outer wall section in the radial space between these wall sections. The inner and outer collars each define an end position of the actuator,Secondly, dirt ingress via the respective free end of each wall section is minimized. The axial length of the central section between the collars determines (as far as the point of penetration is concerned) the maximum travel of the actuator. A component to be actuated, e.g., a rim cover or part thereof, can be coupled to the outer part of the actuator. Uses according to the invention The present invention also encompasses the use of at least two electromechanical systems according to the invention as described above, wherein the at least two electromechanical systems are fixedly arranged in the central cavities of wheel hubs of at least two vehicle wheels, in particular steered vehicle wheels, of a vehicle, wherein a respective electromechanical system acquires measurement data on a current state of the vehicle wheel by means of one or more sensors of the electromechanical system, wherein these measurement data or information obtained from these measurement data are wirelessly transmitted to an electronic system of the vehicle by means of a first communication device of the electromechanical system, and wherein the electronic system of the vehicle takes the transmitted measurement data or information into account when adjusting vehicle properties and / or when controlling the vehicle.The electromechanical systems can easily provide measurement data or information derived from measurement data to the vehicle's electronic system. These systems offer high operational reliability and can be designed compactly, thus freeing up installation space for desired sensors and other components. Furthermore, the motor and actuator of the respective electromechanical system can be used to move a connected component, in particular to open and close a wheel cover. To control a wheel cover, measurement data or derived information from the local electromechanical system and / or other electromechanical systems, especially temperature, speed, and / or dynamic pressure (airflow) data, can be evaluated.One or more sensors can be set up wholly or partially by a sensor system described above. A particularly advantageous variant of the invention is one in which the vehicle's electronic system uses the transmitted measurement data or information to operate the vehicle's Electronic Stability Program (ESP). The ESP can operate exclusively with the measurement data and information transmitted by the electromechanical systems, or the aforementioned transmitted measurement data and information can increase the safety level of a conventional ESP through additional redundancy. Alternatively or additionally to ESP, for example, an adaptive chassis control system can also be operated using the transmitted measurement data or information. Further advantages of the invention will become apparent from the description and the drawing. Likewise, the features mentioned above and those described in more detail below can each be used individually or in any combination according to the invention. The embodiments shown and described are not to be understood as an exhaustive list, but rather serve as examples for illustrating the invention. Detailed description of the invention and drawing Fig. 1 shows a schematic side view of an exemplary embodiment of the electromechanical system according to the invention; Fig. 2 shows a schematic longitudinal section through the embodiment of Fig. 1; Fig. 3 shows a highly schematic representation of the embodiment of Fig. 1 in a side view without housing, coupling device and actuator, illustrating electrical connections provided by rigid connecting pins and spring contact pins; Fig. 4 shows a highly schematic representation of the embodiment of Fig. 1 in a cross-sectional view perpendicular to the longitudinal axis, illustrating the structure of the actuator; Fig. 5 shows a highly schematic representation of the embodiment of Fig. 1 in a longitudinal section view, illustrating a through-hole for the actuator in the housing; Fig.Figure 6 shows a highly schematic representation of an electromechanical system according to the invention in an exemplary embodiment installed in the cavity of a wheel hub of a vehicle wheel, with the rim cover mounted in the closed position; Figure 7 shows the installed electromechanical system of Figure 6, with the rim cover in the open position; Figure 8 shows a highly schematic top view of a vehicle wheel with an installed electromechanical system in an exemplary embodiment, with a multi-part rim cover; Figure 9 schematically shows a top view of a main circuit board of an electromechanical system according to the invention in an exemplary embodiment; Figure 10 shows a highly schematic side view of a vehicle, on whose wheels electromechanical systems according to the invention are installed, in an exemplary use according to the invention. Figures 1, 2, 3, 4 to 5 show an electromechanical system 1 according to the invention in an exemplary embodiment. The figures illustrate various aspects of the electromechanical system 1 in a schematic manner. Figure 1 shows a side view from the outside, Figure 2 shows a longitudinal section through all components, Figure 3 shows a side view of an inner part of the electromechanical system 1, in particular without a housing, Figure 4 shows a cross-section in the area of ​​the actuator, and Figure 5 shows another longitudinal section in the area of ​​a connecting structure 2c of the actuator 2. As can be clearly seen in Fig. 1, the electromechanical system 1, in the illustrated embodiment, has a substantially cylindrical housing 3, which forms an external thread 5 at a front end 4, allowing it to be screwed into a corresponding mating thread of a wheel hub (not shown in detail, but see, for example, Fig. 6). At a rear end 6, the housing 3 forms an end cap 7. If desired, a lighting device 8 can be integrated into the end cap 7 (shown with dashed lines). An outer part 2a of the actuator 2 is movable along a longitudinal axis LA of the electromechanical system 1; the actuator 2 is driven by a motor located inside the housing 3 (obscured in Fig. 1, see, for example, Fig. 2 or Fig. 5). The outer part 2a forms a circumferential ring 9, from which tabs 10 project.Swivel flaps of a rim cover can be attached to the tabs 10 (see, for example, Fig. 6). With a sensor unit integrated into the electromechanical system 1 (see Fig. 9), linear movements, angular movements, and magnetic field measurements can be performed with respect to the local axes Ix, Iy, and Iz. Note that the local axes Ix, Iy, and Iz move with the electromechanical system 1, thus also due to the rotational movement of a vehicle wheel to which the electromechanical system 1 is attached, or due to vibrations of the vehicle wheel. The local axes Ix, Iy, and Iz represent local (linear) axes of motion, local axes of rotation, and local magnetic field measurement directions for the associated measurements; typically, measurement data is converted to the vehicle axes (see Fig. 10). The local axis Iy lies on the longitudinal axis LA, which simultaneously represents the axis of rotation of the vehicle wheel in the mounted state of the electromechanical system 1. The local axes Ix, Iy, and Iz are perpendicular to each other. In the longitudinal section of Fig. 2 along the longitudinal axis LA, the components or component parts of the electromechanical system 1 lying inside the housing 3 can be seen. A generator 11 is arranged at the front end 4. Permanent magnets 13 are rigidly mounted on a radially internal rotor 12, which is located on the longitudinal axis LA. An unbalanced mass 14 is also rigidly attached to the rotor 12. The rotor 12 can rotate about the longitudinal axis LA relative to a stator 15, which is rigidly arranged in the electromechanical system 1. The stator 15 has electromagnetic coils 16. When the wheel (not shown, but see, for example, Fig. 10), in which the electromechanical system 1 is rigidly installed, rotates while the associated vehicle is in motion, the unbalanced mass 14 is held in a lower position by gravity. Consequently, the stator 15 rotates around the rotor 12 together with the vehicle wheel. During this rotation, the permanent magnets 13 induce an electric current in the electromagnetic coils 16. This electric current is supplied to a generator circuit board 17. The generator board 17 is connected to an intermediate board 18 by several spring contact pins 19a in order to transfer electrical energy to the intermediate board 18 and also to transmit control signals. The generator 11 extends through the intermediate board 18. Between the intermediate board 18 and a main board 22, which is located at the rear end 6 of the electromechanical system 1, lies a storage system 20 for storing electrical energy, which here comprises six storage elements 21 (only one of the storage elements 21 is shown in Fig. 2, but see, for example, Fig. 4). The storage elements 21 are approximately cylindrical and lie parallel to the longitudinal axis LA in a radially outer region within the housing 3. The storage elements 21 are each electrically connected at one end terminal to the intermediate board 18 via spring contact pins 19b, and at another end terminal to the main board 22 via spring contact pins 19c. The storage elements are rechargeable batteries, e.g., lithium-ion batteries. The storage elements 21 surround a motor 23 and a coupling device 24, which are arranged in a radially inner region of the housing 3. The coupling device 24 comprises a gearbox 25, which reduces the rotation of a shaft 23a (also called motor shaft) of the motor 23 to a shaft 25a (also called transmission shaft) of the gearbox 25. The coupling device 24 also includes a spindle 26, which is rigidly coupled to the transmission shaft 25a. The spindle 26 can rotate about the longitudinal axis LA on a bearing 27. The spindle 26 is cup-shaped and surrounds the gearbox 25. An external thread 28 is formed on the radial outer surface of the cup-shaped spindle 26. The motor 23 is equipped with a motor circuit board 29. The motor circuit board 29 is electrically connected to the main circuit board 22 via spring contact pins 19d.Through these electrical connections, the motor can obtain electrical energy and receive control commands. An inner part 2b of the actuator 2 is screwed onto the external thread 28 of the spindle 26. This inner part 2b is designed as a circumferential ring 31 and has a corresponding internal thread 30. The inner part 2b is rigidly connected to the outer part 2a of the actuator 2 via connecting elements (not fully visible in Fig. 2, but see Fig. 4). The actuator 2 is held rotationally fixed within the electromechanical system 1, specifically at the through-holes 37 of the housing 3 (see also Fig. 4). When the spindle 26 inside the electromechanical system 1 is rotated about the longitudinal axis LA by means of the motor 23 and the gearbox 25, the inner part 2b of the rotationally fixed actuator 2, with its internal thread 30, moves axially, i.e., along the longitudinal axis LA, on the external thread 28 of the spindle 26. This results in actuator 2 moving linearly overall.The tabs 10 on the outer part 2a of the actuator 2 can then be used to operate a rim cover (see Fig. 6 and Fig. 7). Because the storage system 20, and in particular the storage elements 21, radially surround the motor 23, the motor is protected from heat radiation acting on the housing 3 from the radial outside. The storage system 20 shields against heat radiation and also temporarily stores any heat that does penetrate, so that such heat (at least during short periods of exposure) does not reach the motor 23, and it remains operational. The storage elements 21 generally extend a significant portion of the axial length of the motor 23 (at least 75% of the axial length of the motor 23, preferably at least 90%). Furthermore, the coupling device 24 is arranged axially on the side of the motor 23 facing the front end 4, i.e., between the generator 11 and the motor 23.Thermal radiation and introduced heat penetrating from the front end 4 to the electromechanical system 1 are then shielded or temporarily stored by the generator 11 and the coupling device 24. Generally, the storage elements 21 also extend axially beyond a substantial portion of the coupling device 24 (at least 75% of the length of the transmission 25, preferably at least 90%). This also protects the motor 23 from overheating and maintains its operational readiness to a high degree. Similarly, the main circuit board 22 is also protected from heat penetrating from the front end 4. Note that in practice, when the electromechanical system 1 is installed on the wheel hub of a vehicle wheel, the front end 4 faces the brakes and is therefore most exposed to the heat from the brakes.Furthermore, the wall of the wheel hub, into which the electromechanical system 1 is inserted, typically conducts some of the heat from the brakes, leading to a radial heat input onto the electromechanical system. The electromechanical system 1 according to the invention can effectively counteract this heat input by shielding the particularly sensitive components, namely the motor 23 and the main circuit board 22, radially by means of the storage system 20 and, as shown here, preferably also axially by means of the generator 11 and the coupling device 24. The electrical connections of the components of the electromechanical system 1 relevant for the electrical functions can be seen in the non-scale schematic representation of Fig. 3. As already mentioned, the generator board 17 of the generator 11 is electrically connected to the intermediate board 18 via spring-loaded contact pins 19a, in particular for the transmission of electrical energy and control signals, and possibly also sensor signals. The storage elements 21 are electrically connected to the intermediate board 18 via spring-loaded contact pins 19b, and to the main board 22 via spring-loaded contact pins 19c. The motor board 29 of the motor 23 is electrically connected to the main board 22 via spring-loaded contact pins 19d, in particular for the transmission of electrical energy and control signals, and possibly also sensor signals. Furthermore, the intermediate board 18 and the main board 22 are electrically connected via electrically conductive, rigid connecting pins 32 (also called rigid connecting rods) for the transmission of electrical energy and the exchange of control commands, and possibly also sensor signals. The circuit boards 17, 18, 22, 29 are provided with conductor tracks (not shown in detail), each of which has an electrical contact (not shown in detail). Electronic components such as control units, sensors and wireless communication devices are arranged on the mainboard 22 (see also Fig. 9). The spring contact pins 19a-19d, shown by way of example in the lower right of Fig. 3, are each constructed with a pin 33 that is movable in a metallic sleeve 34 (also called a sleeve) in a displacement direction VR. The displacement direction VR is parallel to the longitudinal axis LA. The pin 33 is biased into an extended position by a spring 35 arranged in the sleeve 34. The spring 35 can, for example, be designed as a metallic helical spring that rests between an end stop 34a of the sleeve 34 and a thickened end section 33a of the pin 33. Against the force of the spring 35, the pin 33 can be pushed or pressed into the sleeve 34. The sleeve 34 is typically fixed to a circuit board 17, 18, 22, 29 in the region of its end stop 34a and is thus electrically contacted. The pin 33 presses on a structure (e.g., a storage element 21) by means of the spring 35, thereby electrically contacting this structure.Pin 33 and sleeve 34 are each electrically conductive (preferably by being made of metal) and are in contact with each other (here in the area of ​​the thickened end section 33a), so that an electrical contact can be established between their ends via the spring contact pin 19a-19d. The spring contact pins facilitate the electrical contacting during the assembly of the electromechanical system 1. In the illustrated embodiment, all electrical connections between the generator 11, the motor 23, the storage elements 21, the intermediate board 18, and the main board 22 are established via spring-loaded contact pins 19a-19d and rigid connecting pins 32. These electrical connections are relatively insensitive to the centrifugal forces that occur when the electromechanical element 2 rotates together with the vehicle wheel. Fig. 4 shows a cross-section perpendicular to the longitudinal axis LA in an axially central region, and Fig. 5 shows a longitudinal section along the longitudinal axis LA, schematically illustrating the structure of the electromechanical system 1. Note that the representation in Fig. 5 focuses on the area to the right of the longitudinal axis LA (i.e., the area to the right of the longitudinal axis LA is not shown for simplification), and both Fig. 4 and Fig. 5 are not to scale. The motor 23 and the gearbox 25 located below it are arranged centrally on the longitudinal axis LA, with the spindle 26 coupled to it (see also Fig. 2). The external thread 28 of the spindle 26 engages in the internal thread 31 of the radially inner part 2b of the actuator 2. The inner part 2b is formed with a circumferential ring 31. The inner part 2b is rigidly connected to the radially outer part 2a of the actuator 2 by means of three connecting elements 2c of the actuator 2. The outer part 2a of the actuator 2 is also formed with a circumferential ring 9. The connecting elements 2c penetrate a longitudinal wall 38 (shown with dashed lines) of the housing 3 at three penetration points 37. Accordingly, the outer part 2a of the actuator 2 lies outside the housing 3. Five tabs 10 are arranged on the outer part 2a, with which a rim cover can be hinged (see, for example, Fig. 6). At the penetration points 37, the connecting elements 2c abut the housing 3 laterally in the circumferential direction, so that the actuator 2 is rotationally fixed with respect to the longitudinal axis LA. However, the actuator 2 can be moved in the longitudinal direction LR, i.e., parallel to the longitudinal axis LA, by rotating the spindle 26 about the longitudinal axis LA. The storage elements 21 of the electrical energy storage system 20 are arranged in the radial area between the inner part 2b of the actuator 2 and the longitudinal wall 38 of the housing 3. In the illustrated configuration, three groups 39a, 39b, 39c of storage elements 21 are provided, each group comprising two storage elements 21. All storage elements 21 are arranged on a uniform radius RS (measured from the longitudinal axis LA to the center of each storage element 21). The groups 39a-39c are arranged uniformly in the circumferential direction UR. The storage elements 21 of a group 39a-39c are closely adjacent to each other in the circumferential direction UR; however, there is a distinct gap 40 between adjacent groups 39a, 39b, 39c in the circumferential direction UR. Accordingly, the storage elements 21 are partially spaced apart from each other in the circumferential direction UR by the gaps 40, as shown in the group arrangement.A connecting element 2c projects radially through each gap 40. At each penetration point 37, the longitudinal wall 38 has a radially inner wall section 38a (which is arranged at the top in Fig. 5) and a radially outer wall section 38b. The two wall sections 38a, 38b, which run along the longitudinal axis LA, are spaced apart from each other in the radial direction, also called the transverse direction QR, by a gap 41. Furthermore, the wall sections 38a, 38b are offset from each other along the longitudinal direction LR, here without overlap in the longitudinal direction (alternatively, the wall sections 38a, 38b can also be partially offset from each other, i.e., arranged with a partial overlap in the longitudinal direction LR, not shown in detail). The free end FI of the inner wall section 38a ("inner free end" FI) and the free end FA of the outer wall section 38b ("outer free end" FA) are opposite each other. In the gap 41 between the wall sections 38a, 38b lies a central section 2d of the actuator 2, which is aligned parallel to the wall sections 38a, 38b and overlaps with the free ends FI, FA (in the illustrated travel position of the actuator 2, and also in all other possible travel positions). With an inner collar 2e, the actuator 2 overlaps the inner free end FI in the transverse direction QR, and with an outer collar 2f, the actuator 2 overlaps the outer free end FA in the transverse direction QR. The inner collar 2e transitions into the remaining connecting element 2c, which extends to the inner part 2b. The outer collar 2f transitions into the outer part 2a of the actuator 2, which here comprises a circumferential ring 9.The inner collar 2e and the outer collar 2f, together with the free ends FA, FI as stops, limit the travel path of the actuator 2 in the longitudinal direction LR; however, if desired, separate stops 42 for the actuator 2 can also be provided to limit the travel path. The middle part 2d and the two collar parts 2e, 2f largely block the passage 37, so that the interior of the housing 3 is protected from contamination. Figures 6 and 7 illustrate in schematic longitudinal section along the longitudinal axis LA an exemplary electromechanical system 1, similar to that shown in Figures 1, 2, 3, 4 to 5, in the installed state in a wheel hub 43 for a vehicle wheel 44. The wheel hub 43 is rigidly connected to a vehicle axle in a manner not shown in detail, via which the driving force is transmitted to the vehicle wheel 44. The wheel hub 43 therefore rotates during travel, and with it the electromechanical system 1. The wheel hub 43 forms an approximately cylindrical, central cavity 43a. The electromechanical system 1 is screwed into an internal thread 45, which the wheel hub 43 forms on the side wall of the cavity 43a, via the external thread 5 of its housing 3, and is fixed in the screwed-in state in a manner not shown in detail, in particular also fixed against rotation. A rim 46 of the vehicle wheel 44 is fixed to the wheel hub 43. It is fixed by bolts 48, which are fixed to the wheel hub 43 and protrude through the rim 46. Lock nuts 48a are screwed onto the ends of each bolt 48 (in Figures 6 and 7, the rim 46 is shown slightly raised from the wheel hub 43 to better distinguish it from the hub; in practice, however, the rim 46 is clamped to the wheel hub 43 by the lock nuts 48a). A tire 47 is mounted on the rim 46. The outer part 2a of the actuator 2 is movable along the longitudinal direction LR on the housing 3 of the electromechanical system 1 (see, for example, Fig. 5). A rim cover 49 is coupled to the tabs 10 of the actuator 2. The rim cover 49 is designed in multiple parts and comprises several pivot flaps 49a, 49b. Each radially inner end of a pivot flap 49a, 49b is pivotally connected to a tab 10. Furthermore, each pivot flap 49a, 49b is held by a pivot bracket 50 and is pivotable about a local pivot axis perpendicular to the longitudinal axis LA. The pivot bracket 50 is rigidly attached to the rim 46. Fig. 6 shows the rim cover 49 in a closed position; this corresponds to the actuator 2 being moved upwards in the longitudinal direction LR (towards the rear end 6 of the electromechanical system 1). The pivot flaps 49a, 49b are folded down (with their radially outer ends) onto the rim 46. In this position, the vehicle wheel 44 has particularly low air resistance during driving. However, only a small amount of cooling air reaches the rim 46 and passes under the rim 46 through openings in the rim 46 (openings not shown in detail). Fig. 7 shows the rim cover 49 in an open position; this corresponds to the actuator 2 being moved downwards in the longitudinal direction LR (towards the front end 4 of the electromechanical system 1). The pivot flaps 49a, 49b are folded away from the rim 46 (with their radially outer ends). In this position, a particularly large amount of cooling airflow reaches the rim 46. However, this increases the air resistance of the vehicle wheel 44. Note that braking while driving causes the wheel hub 43 to heat up from below (as shown in Figs. 6 and 7), and this heat is transferred to the electromechanical system 1 to a considerable extent. Heat is introduced axially from below into the front end 4 of the electromechanical system 1, but also radially from the outside into a part of the electromechanical system 1 near the front end 4, especially where the electromechanical system 1 overlaps the wheel hub 43 in the axial direction. However, the internal design of the electromechanical system 1 effectively protects the particularly sensitive motor and the main circuit board (see, for example, Fig. 2) from heat input from the radial outside (and also from below), thus ensuring a high level of operational reliability. Fig. 8 shows again in a perspective view, almost along the longitudinal axis, a rim cover 49 with here five pivot flaps 49a-49e, which can be pivoted towards and away from the rim 46 by means of the electromechanical system 1 in the manner shown above. Fig. 9 shows a schematic top view of a main circuit board 22 for an electromechanical system according to the invention. The mainboard 22 includes a main processor 51, on which various electronic functions are wholly or partially implemented, in particular control functions for other components on the mainboard 22 and components of the electromechanical system outside the mainboard 22. Specifically, the main processor 51 can control the motor that actuates the actuator to operate the rim cover. Furthermore, the main processor 51 monitors and controls the charging and discharging of the storage system, and it also monitors and controls the generator. A sensor system 52 (also called a sensor unit) is installed on the mainboard 22. This system includes a 6D motion sensor 53, which can determine linear movements about three orthogonal, local axes of motion and angular movements about three orthogonal, local axes of rotation; the three local axes of motion and the three local axes of rotation are identical to each other. The 6D motion sensor 53 is designed with a combination of accelerometer and gyroscope for this purpose. The sensor system 52 also includes a magnetometer 54, which can measure the magnetic field strength of the Earth's magnetic field at the location of the magnetometer 54 along three orthogonal, local magnetic field measurement directions. The local magnetic field measurement directions correspond to the local directions of motion and rotation axes.The measurement data from the sensor system 52 are transmitted to an evaluation unit 55, which is integrated into the main processor 51. The evaluation unit 55 performs a coordinate transformation on the measurement data received from the sensor system 52 in order to convert it into the vehicle's coordinate system (see Fig. 10). Furthermore, the evaluation unit 55 converts the measurement data into physical quantities (i.e., linear velocity, angular velocity, and magnetic field strength). Furthermore, a temperature sensor 58 is integrated on the mainboard 22. Its measurement data is also transmitted to the evaluation unit 55. The evaluation unit 55 also receives measurement data from other temperature sensors located on the generator, the storage system, and the motor (not shown in detail). A pressure sensor 36 is also integrated on the mainboard 22, which can be used to measure the ambient pressure ("air pressure"). Its measurement data is also transmitted to the evaluation unit 55. Mounted on the mainboard 22 is also a lighting device 8, which is controlled by the main processor 51. The lighting device 8 typically comprises several LEDs, which are distributed across the mainboard 22 and connected to light guide elements (e.g., Plexiglas structures) that lead to the end cap of the electromechanical system (not shown in detail, but see Fig. 1). To receive control commands from the vehicle, or to transmit measurement data or information derived from the measurement data to the vehicle, a first communication device 56 is integrated on the mainboard 22. The electronic part 56a of the first communication device 56 is integrated into the main processor 51. The first communication device 56 also has an antenna 56b. Here, the first communication device 56 is configured for Bluetooth Low Energy (BLE) communication. To receive measurement data from an external sensor, such as one integrated into the valve of the vehicle's tire, or to transmit energy to the external sensor, a second communication device 57 is installed on the mainboard 22. The electronic part 57a of the second communication device 57 is integrated into the main processor 51. The second communication device 57 also has an antenna 57b. Here, the second communication device 57 is configured for Bluetooth NFC / RF communication. Integrated into the main processor 51 is an energy control unit 59. This unit determines, in particular, which components and parts or functions of components and parts are activated, partially activated, or deactivated at any given time. This allows the available electrical energy, generated by the generator and / or stored in the storage system, to be used in such a way as to achieve a high operational readiness of the essential functions of the electromechanical system. Furthermore, a magnetically actuated switch 60 (also called a magnetic switch) is arranged on the main circuit board 22, which can be actuated from the outside (i.e., from outside the housing of the electromechanical system) by means of a magnet. The electromechanical system can be fully or partially activated and deactivated by means of the magnetic switch. The electromechanical system, and in particular the main processor 51 of the mainboard 22, can serve as a data aggregator for measurement data from sensors 53, 54, 58, 36 or also from external sensors or information derived therefrom, and transmit this data to the vehicle's electronic system by means of the first communication device 56 (see also Fig. 10). The mainboard 22 often also includes a DC-DC converter (not shown in detail). Figure 10 schematically depicts a vehicle 61, on whose wheel hubs 43 of the vehicle wheels 44 electromechanical systems 1 according to the invention are installed. The vehicle 61 illustrated here by way of example has four vehicle wheels 44; two of these are visible in the view of Figure 10 (the other two vehicle wheels on the side of the vehicle facing away from the viewer in Figure 10 would be essentially obscured and are therefore not shown in detail). In the presented example, each of the four vehicle wheels 44 of the vehicle 61 is equipped with an electromechanical system 1; it is generally preferred to equip all vehicle wheels 44 of a vehicle 61 with electromechanical systems 1 according to the invention.Note that in other uses only some of the vehicle wheels of a vehicle may be equipped with electromechanical systems, typically wherein the vehicle wheels of only some of the axles of the vehicle are equipped with electromechanical systems, preferably including at least the steered axle (not shown in detail). Vehicle axes x, y, z can be assigned to the vehicle 61, shown here on one of the wheels 44. The x-axis corresponds to the (horizontal) forward direction of travel of the vehicle 61; as a rotation axis, this corresponds to the roll axis of a vehicle wheel 44. The y-direction is the horizontal direction perpendicular to the forward direction of travel; as a rotation axis, this corresponds to the pitch axis. The z-direction is the vertical axis perpendicular to the forward direction of travel; as a rotation axis, this corresponds to the yaw axis. The measured values ​​determined on an electromechanical system 1 or on a vehicle wheel 44 are typically converted to the vehicle axes by a coordinate transformation. In the illustrated example, external sensors 66 are arranged remotely from the electromechanical systems 1 at the vehicle wheels 44. In this example, these sensors are configured as tire pressure sensors 67 and tire temperature sensors 68. These sensors transmit measurement data to the respective second communication unit of the electromechanical system 1 via NFC / RF communication (see Fig. 9). Furthermore, the second communication unit also wirelessly transmits energy to the external sensors 66, which can therefore be passive, i.e., without their own power supply. In other embodiments, the external sensors 66 can also determine other physical quantities of interest as needed, for example, ambient brightness to activate and deactivate a lighting device as position lighting (not shown in detail). The electromechanical systems 1 of the vehicle wheels 44 communicate with their respective first communication devices (see Fig. 9) with an electronic system 62 of the vehicle 61 via a vehicle-side communication device 63; this is configured for BLE. Measurement data from the respective sensor system and / or other sensors of the electromechanical systems 1 and / or external sensors, or information derived therefrom, are transmitted to the electronic system 62 of the vehicle 61. This allows the current state (in particular, the state of motion) of the electromechanical systems 1 or the vehicle wheels 44 to be communicated to the electronic system 62 of the vehicle 61. An ESP control unit 64 of the electronic system 62 of the vehicle 61 evaluates (at least partially) this measurement data or information and derives commands from it to control the vehicle 61.In particular, control commands are generated for the brake control unit 65 and transmitted to it. The brake control unit 65 then controls the brakes of the vehicle 61, thereby implementing, for example, an anti-lock braking system. Similarly, chassis settings, for example, can be controlled (not shown in detail). Reference symbol list 1 Electromechanical system 2 Actuator 2a Outer part of the actuator 2b Inner part of the actuator 2c Connecting elements of the actuator 2d Middle section of the actuator 2e Inner collar of the actuator 2f Outer collar of the actuator 3 Housing 4 Front end 5 External thread 6 Rear end 7 End cap 8 Lighting device 9 Circumferential ring (outer part of the actuator) 10 Tab 11 Generator 12 Rotor 13 Permanent magnets 14 Unbalance (unbalance component) 15 Stator 16 Electromagnetic coils 17 Generator board 18 Intermediate board 19a Spring contact pins (generator board to intermediate board) 19b Spring contact pins (storage elements to intermediate board) 19c Spring contact pins (storage elements to main board) 19d Spring contact pins (motor board to main board) 20 Storage system 21 Memory element 22 Mainboard 23 Motor 23a Motor shaft 24 Coupling device 25 Gearbox 25a Gearbox shaft 26 Spindle 27 Spindle bearing 28 External thread (on spindle) 29 Motor board 30Internal thread (on the inner part of the actuator) 31 Circumferential ring (inner part of the actuator) 32 Rigid connecting pin 33 (Movable) pin 33a Thickened end section of the pin 34 Sleeve (sleeve) 34a End stop of the sleeve 35 Spring 36 Pressure sensor (on main board) 37 Through-hole 38 Longitudinal wall 38a Inner wall part of the longitudinal wall 38b Outer wall part of the longitudinal wall 39a-39c Groups of storage elements 40 Space (between groups of storage elements) 41 Gap (between inner wall part and outer wall part) 42 Separate stop 43 Wheel hub 43a Central cavity (wheel hub) 44 Vehicle wheel 45 Internal thread (wheel hub) 46 Rim 47 Tire 48 Screw bolt 48a Union nut 49 Rim cover 49a-49e Pivot flaps (of the Rim cover) 50 Swivel bracket 51 Main processor 52 Sensor system 53 6D motion sensor 54 Magnetometer 55 Evaluation unit 56 First communication unit 56a Electronic part (first communication unit) 56b Antenna (firstCommunication device) 57 Second communication device 57a Electronic part (second communication device) 57b Antenna (second communication device) 58 Temperature sensor 59 Energy control device 60 Magnetically actuated switch 61 Vehicle 62 Electronic system of the vehicle 63 Vehicle-side communication device 64 ESP control unit 65 Brake control 66 External sensor 67 Tire pressure sensor 68 Tire temperature sensor FA (outer) free end of the outer wall part FI (inner) free end of the inner wall part LA Longitudinal axis LR Longitudinal direction (parallel to longitudinal axis) Ix, Iy, Iz Local axes of movement / axis of rotation / magnetic field measurement directions QR Transverse direction (perpendicular to the longitudinal axis) RS Uniform radius of the storage elements UR Circumferential direction VR Displacement direction x, y, z Vehicle axes

Claims

Electromechanical system (1) for stationary arrangement in a central cavity (43a) of a wheel hub (43) of a vehicle (61), wherein the electromechanical system (1) comprises: - a generator (11) for generating electric current, - an electric motor (23) for actuating an actuator (2), - the actuator (2), and - a storage system (20) for storing electrical energy, characterized in that the actuator (2) is linearly movable along a longitudinal axis (LA) of the electromechanical system (1), that a coupling device (24) couples the motor (23) to a radially inner part (2b) of the actuator (2), that the storage system (20) has several storage elements (21) which are arranged radially outside around the longitudinal axis (LA) and around the motor (23) and are at least partially spaced apart from each other in a circumferential direction (UR), and that a radially outer part (2a) of the actuator (2) is formed radially beyond the storage elements (21),wherein connecting elements (2c) of the actuator (2) rigidly connect the radially inner part (2b) and the radially outer part (2a) to each other and extend between the storage elements (21). Electromechanical system (1) according to claim 1, characterized in that the coupling device (24) comprises a spindle (26) which is rotatably mounted about the longitudinal axis (LA) and which can be driven by the motor (23), that the spindle (26) has an external thread (28), that the actuator (2) has an internal thread (30) on its radially inner part (2b) which is screwed onto the external thread (28) of the spindle (26), and that the actuator (2) is mounted in a rotationally fixed manner with respect to the longitudinal axis (LA). Electromechanical system (1) according to claim 2 , characterized in that the coupling device (24) comprises a gearbox (25) which reduces the rotation of a shaft (23a) of the motor (23) to the spindle (26). Electromechanical system (1) according to one of the preceding claims, characterized in that a rim cover (49) for a vehicle wheel (44) mounted on the wheel hub (43) is coupled to the radially outer part (2a) of the actuator (2). Electromechanical system (1) according to one of the preceding claims, characterized in that the electromechanical system (1) has a front end (4) with which the electromechanical system (1) can be inserted into the cavity (43a) of the wheel hub (43), and has a rear end (6) opposite along the longitudinal axis (LA), and in that along the longitudinal axis (LA) from the front end (4) to the rear end (6) a sequence of components of the electromechanical system (1) is arranged as follows: generator (11), coupling device (24), motor (23). Electromechanical system (1) according to claim 5, characterized in that the electromechanical system (1) also comprises an intermediate board (18) and a main board (22), and that along the longitudinal axis (LA) from the front end (4) to the rear end (6) the sequence of components of the electromechanical system (1) is arranged as follows: generator (11), intermediate board (18), coupling device (24), motor (23), main board (22). Electromechanical system (1) according to one of the preceding claims, characterized in that the generator (11) and the motor (23) are of identical construction. Electromechanical system (1) according to one of the preceding claims, characterized in that the electromechanical system (1) comprises a sensor system (52), wherein the sensor system (52) is configured to measure linear movements of the electromechanical system (1) with respect to at least a first local axis of motion (Ix) and a second local axis of motion (Iy), which are linearly independent, as well as angular movements of the electromechanical system (1) with respect to at least a first local axis of rotation (Ix) and a second local axis of rotation (ly), which are linearly independent of each other. Electromechanical system (1) according to claim 8, characterized in that the sensor system (52) is further configured to measure linear movements of the electromechanical system (1) with respect to a third local axis of motion (Iz), wherein all local axes of motion (Ix, Iy, Iz) are linearly independent, as well as angular movements of the electromechanical system (1) with respect to a third local axis of rotation (Iz), wherein all local axes of rotation (Ix, Iy, Iz) are linearly independent. Electromechanical system (1) according to claim 8 or 9, characterized in that the sensor system (52) is further configured to measure a magnetic field strength at a measuring location in the electromechanical system (1) with respect to at least a first local magnetic field measurement direction (Ix) and a second local magnetic field measurement direction (ly), which are linearly independent. Electromechanical system (1) according to claim 10, characterized in that the sensor system (52) is further configured to measure the magnetic field strength at the measurement location in the electromechanical system (1) with respect to a third local magnetic field measurement direction (Iz), wherein all local magnetic field measurement directions (Ix, Iy, Iz) are linearly independent. Electromechanical system (1) according to one of claims 8 to 11, characterized in that a local axis of motion (Iy) and a local axis of rotation (ly) are selected as the longitudinal axis (LA) of the electromechanical system (1), which also corresponds to an axis of rotation of the wheel hub (43) in the assembled state of the electromechanical system (1). Electromechanical system (1) according to one of the preceding claims, characterized in that the generator (11) comprises a stator (15) fixed in the electromechanical system (1) and a rotor (12) rotatable relative to the stator (15), wherein the rotor (12) is designed with an imbalance (14). Electromechanical system (1) according to claim 13, characterized in that the rotor (12) is rotatably mounted within the stator (15), that one or more permanent magnets (13) are formed on the rotor (12), and that one or more electromagnetic coils (16) are formed on the stator (15). Electromechanical system (1) according to one of the preceding claims, characterized in that the electromechanical system (1) has an intermediate board (18) and a main board (22), wherein electrical connections are provided - between the intermediate board (18) and the storage system (20), - between the storage system (20) and the main board (22), and - between the intermediate board (18) and the main board (22). Electromechanical system (1) according to claim 15, characterized in that all electrical connections of the electromechanical system (1) between the generator (11), the intermediate board (18), the storage system (20), the main board (22) and the motor (23) are provided by means of spring contact pins (19a-19d) and / or rigid connecting pins (32). Electromechanical system (1) according to claim 15 or 16, characterized in that spring contact pins (19a-19d) establish the electrical connections between the intermediate board (18) and the storage system (20), and between the storage system (20) and the main board (22). Electromechanical system (1) according to one of the preceding claims, characterized in that the electromechanical system (1) comprises several spring contact pins (19a-19d) for establishing electrical connections. Electromechanical system (1) according to one of the preceding claims, characterized in that the electromechanical system (1) has a first communication device (56) configured for wireless communication to an electronic system (62) of the vehicle (61). Electromechanical system (1) according to one of the preceding claims, characterized in that the electromechanical system (1) has a second communication device (57) configured for wireless communication to one or more external sensors (66). Electromechanical system (1) according to one of the preceding claims, characterized in that the electromechanical system (1) has an evaluation device (55) for evaluating measurement data from sensors (53, 54, 58, 36) of the electromechanical system (1) and / or from external sensors (66). Electromechanical system (1) according to one of the preceding claims, characterized in that the electromechanical system (1) has at least one temperature sensor (58). Electromechanical system (1) according to claim 22, characterized in that the electromechanical system (1) has several temperature sensors (58) which each measure a temperature at a different location on the electromechanical system (1). Electromechanical system (1) according to one of the preceding claims, characterized in that the electromechanical system (1) comprises one or more pressure sensors (36) for measuring a pressure in the environment of the electromechanical system (1). Electromechanical system (1) according to one of the preceding claims, characterized in that the electromechanical system (1) comprises at least one lighting device (8) which is supplied with electrical energy by means of the generator (11) and / or the storage system (20). Electromechanical system (1) according to one of the preceding claims, characterized in that the electromechanical system (1) has at least one magnetically actuated switch (60) with which the electromechanical system (1) can be fully and / or partially activated and deactivated from outside a housing (3) of the electromechanical system (1). Electromechanical system (1) according to one of the preceding claims, characterized in that the electromechanical system (1) has an energy control device (59) for controlling the consumption of electrical energy, with which components and / or functions of components of the electromechanical system (1) can be activated and deactivated. Electromechanical system (1) according to claim 27, characterized in that the energy control device (59) is configured such that - when a first threshold of instantaneously stored electrical energy in the storage system (20) is undershot, one or more components and / or functions of components are deactivated, and / or - when a second threshold of instantaneously stored power of the generator (11) is exceeded, one or more deactivated components or functions of components are reactivated. Electromechanical system (1) according to one of the preceding claims, characterized in that the electromechanical system (1) has a housing (3) with an external thread (5) for screwing into the wheel hub (43) of the vehicle (61). Electromechanical system (1) according to one of the preceding claims, characterized in that the storage system (20) comprises rechargeable batteries and / or high-capacity capacitors.Electromechanical system (1) according to one of the preceding claims, characterized in that the electromechanical system (1) has a housing (3) which has a longitudinal wall (38) extending along the longitudinal axis (LA) in which at least one access point (37) for the actuator (2) is provided, that in the region of each access point (37) in the longitudinal wall (38) an outer wall part (38b) and an inner wall part (38a) are provided which - extend parallel to the longitudinal axis (LA), - but are spaced apart from each other in the transverse direction (QR) perpendicular to the longitudinal axis (LA), - are at least partially offset from each other along the longitudinal axis (LA), so that an inner free end (FI) of the inner wall part (38a) and an outer free end (FA) of the outer wall part (38b) are opposite each other in the region of the access point (37), and that the actuator (2) has at each access point (37):- a middle section (2d),which runs along the longitudinal axis (LA) and is arranged in the transverse direction (QR) between the inner wall part (8a) and the outer wall part (38b), - an inner collar (2e) which is formed at one end of the central section (2d) which faces away from the inner free end (FI) and extends inwards in the transverse direction (QR) over the inner free end (FI), and - an outer collar (2f) which is formed at one end of the central section (2d) which faces away from the outer free end (FA) and extends outwards in the transverse direction (QR) over the outer free end (FA). Use of at least two electromechanical systems (1) according to one of the preceding claims, wherein the at least two electromechanical systems (1) are fixedly arranged in the central cavities (43a) of wheel hubs (43) of at least two vehicle wheels (44) of a vehicle (61), wherein each electromechanical system (1) acquires measurement data on a current state of the vehicle wheel (44) by means of one or more sensors (53, 54, 58, 36) of the electromechanical system (1), wherein these measurement data or information obtained from these measurement data are wirelessly transmitted to an electronic system (62) of the vehicle (61) by means of a first communication device (56) of the electromechanical system (1), and wherein the electronic system (62) of the vehicle (61) takes the transmitted measurement data or information into account when adjusting vehicle properties and / or when controlling the vehicle (61). Use according to claim 32, characterized in that the electronic system (62) of the vehicle (61) uses the forwarded measurement data or information for the operation of an Electronic Stability Program (=ESP) of the vehicle (61).

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