Device for providing an electrically adjustable, contactlessly operating magnetic cogging torque inhibition

Abstract

The proposed device (RH) is intended for providing an electrically adjustable, contactlessly operating magnetic cogging torque inhibition between an electro-permanent magnet (MAG) and a cogging torque ring (RR) which is rotatable about an axis of rotation (D) and has rotor pole shoes (PR) arranged in a distributed manner. The electro-permanent magnet comprises a magnetic core (MK), a coil (SP) surrounding said magnetic core, and a magnetic field conductor (Bo, Bu) connected to each pole end (PE) of the magnetic core. In order to provide the cogging torque inhibition, a suitable current pulse can be impressed into the coil. Both magnetic field conductors extend from the pole ends to the rotor pole shoes and form stator pole shoes at their respective ends, which stator pole shoes lie opposite the cogging torque ring having the rotor pole shoes. The two magnetic field conductors are connected to one another in a rotationally fixed manner. According to the invention, the magnetic field conductors each form a plurality of finger-shaped portions (Fo, Fu) each having a finger end piece (Eo, Eu). The finger end pieces are designed and oriented in a radial outer region (RA) of the electro-permanent magnet in such a way that the finger end pieces of one of the two magnetic field conductors engage between the finger end pieces of the other magnetic field conductor in order to form stator pole shoes having north and south poles which alternate in the circumferential direction.

Description

[0001] Description

[0002] Device for providing an electrically adjustable, non-contact magnetic cogging torque lock

[0003] Technical field

[0004] The invention relates to a device for providing an electrically adjustable, non-contact magnetic cogging torque between an electro-permanent magnet and a cogging torque ring arranged coaxially thereto and rotatable about an axis of rotation. The axis of rotation thus passes through the electro-permanent magnet. The cogging torque ring has a number npR of rotor pole shoes preferably evenly distributed in the circumferential direction relative to the axis of rotation. The electro-permanent magnet comprises a magnetic core or magnetic coil core to form a north and south pole at two pole ends of the magnetic core. The electro-permanent magnet further comprises at least one electrical coil surrounding the magnetic core and a magnetic field conductor magnetically connected to each pole end of the magnetic core.To provide electrically adjustable magnetic cogging torque, a current pulse with suitable current intensity and / or pulse length and current direction can be impressed into at least one electrical coil. Both magnetic field conductors extend from the pole ends of the magnetic core towards the rotor pole shoes of the cogging torque ring and form stator pole shoes at their respective ends. In particular, both magnetic field conductors are rotationally fixed and preferably rigidly connected to each other. The stator pole shoes are arranged opposite the cogging torque ring and rotor pole shoes to provide the cogging torque. In particular, the two magnetic field conductors, the electrical coil, and preferably also the magnetic core are rotationally fixed and, in particular, rigidly connected to each other.In other words, the magnetic field conductors are arranged so that they cannot rotate relative to each other with respect to the axis of rotation of the device. A minimum air gap, typically in the range of 0.1 mm to 2 mm, forms between the rotor pole shoes and the stator pole shoes.

[0005] Depending on the design of the rotor pole shoes and the recesses or grooves located between them circumferentially to the axis of rotation, as well as the magnetic flux guidance, a stator pole shoe in the engaged state can be arranged directly opposite a rotor pole shoe or with a gap, i.e., opposite a recess between two rotor pole shoes. The stator and rotor pole shoes are typically arranged evenly spaced circumferentially to the axis of rotation. One or more stator or rotor pole shoes need not be present or can be omitted entirely, whereby the cogging torque behavior remains unchanged from one engagement to the next over a complete rotation of the cogging torque ring to the electro-permanent magnet.

[0006] The invention further relates to an (extended) electric motor comprising a stator, a rotor rotatably arranged about an axis of rotation of the electric motor, and a device for providing an electrically adjustable, non-contact magnetic cogging torque between the stator and the rotor. The rotor of the (extended) electric motor is either rotationally fixed to the cogging torque ring of the device according to the invention, or the rotor of the (extended) electric motor already forms such a cogging torque ring as part of the device according to the invention.

[0007] The invention further relates to a first and second retrofit unit for retrofitting an electrically adjustable, non-contact magnetic cogging torque limiter to an internal rotor electric motor and an external rotor electric motor, respectively. The aforementioned internal and external rotor electric motors each form a single unit, are part of the prior art, and are commercially available. They can also be referred to as standard electric motors or conventional electric motors.

[0008] The invention further relates to an arrangement consisting of such an (extended) electric motor, of such an internal or external rotor electric motor, each with a first or second retrofit unit according to the invention attached thereto.

[0009] Furthermore, the invention relates to a first actuator comprising such an arrangement and an output-side actuating element with an actuating connection.

[0010] Finally, the invention relates to a second actuator comprising such an arrangement, in particular a reduction gear connected downstream of the electric motor, and an output-side actuating element with an actuating connection.

[0011] The reduction gear can also be omitted in the first and second actuators. In this case, the electric motor, i.e., the (extended) electric motor or the internal or external rotor electric motor according to the state of the art, is configured to directly drive the associated actuator connection of the first or second actuator. Technical background

[0012] From WO 2020 / 109744 A2, an adjustable force device is known, comprising a mechanically guided element to enable a displacement according to a predetermined trajectory, and means for magnetic indexing or tactile detenting of the displacement by means of the magnetic interaction between a first ferromagnetic structure and a second ferromagnetic structure as an integral part of a magnet. The magnet is at least partially surrounded by an electrical coil, which modifies the magnetization of the permanent magnet according to the direction and amplitude of the electric current flowing in the coil.

[0013] This device can be integrated into an electric motor or an actuator (see FIG. 10a, FIG. 11 and FIG. 17 therein).

[0014] Figure 4 shows a further variant in which the second ferromagnetic structure comprises two disks, each with radial external teeth, and forms two main air gaps with the first structure in the region of the teeth formed at the interface of the two structures. The first ferromagnetic structure comprises a tubular first permanent magnet with high coercivity and axial magnetization. Furthermore, the first ferromagnetic structure comprises a cylindrical second permanent magnet with low coercivity and axial magnetization, located coaxially inside the first permanent magnet. The second permanent magnet is rigidly connected to the axis of the force device. The coil surrounds the second inner permanent magnet.The second permanent magnet can be magnetized by means of an electric current pulse applied to the coil, depending on the direction of the current pulse, in a first axial direction or in an opposite second axial direction. The resulting magnetic field acts additively or subtractively to the axial magnetic field of the first permanent magnet to create or suppress magnetic indexing or tactile interlocking between the first and second ferromagnetic structures.

[0015] From WO 2011 / 146076 A1, a holding brake is known, particularly for elevators, for applying a holding torque to a rotatable component of the elevator. The rotatable component can be, for example, a pulley or a sheave around which a traction element is guided, such as a round rope or a flat belt. The traction element can, in turn, be connected to a counterweight and to an elevator car in a suitable rope arrangement. The holding brake comprises a first flange and a second flange, wherein the first and second flanges each include a first and a second set of poles. The second flange is connected to the rotatable component for applying the holding torque and is also rotatably arranged about an axis of rotation of the holding brake relative to the first flange.The first and second sets of poles are located on the radial outer sides of the first and second flanges, respectively, with the poles extending axially from these points. The second flange is positioned within the first flange such that, with respect to the axis of rotation, the radially inner second set of poles is located in close proximity to the radially outer first set of poles. The holding brake also includes a ring assembly positioned between the first and second flanges. This ring assembly may comprise a permanent magnet ring, one or more magnetic cores, and a brake coil. In the active state, the permanent magnet ring generates a magnetic field that attracts the radially opposite poles of the two flanges, thereby stopping the rotation of the second flange.In the passive state, an electric current through the brake coil generates an electromagnetic field which opposes the magnetic field of the permanent magnet ring and demagnetizes the poles, allowing the second flange to rotate freely.

[0016] German patent DE 102021 209914 B3 of the applicant discloses an actuator comprising an electric motor, a downstream reduction gear, and an output-side actuating element with an actuating connection. The electric motor has a stator and, as an external rotor, a rotor cup rotating around an axis of rotation of the electric motor, the rotor cup being magnetically detented in the direction of rotation. The actuator includes a non-contact magnetic detent lock, electrically switchable on and off by means of an electromagnet, for holding or releasing the rotor cup. The electromagnet has a coil arrangement that encloses a magnetic coil core with two pole shoes for the possible formation of two magnetic poles. The electromagnet is designed and arranged relative to the rotor cup such that the two pole shoes are opposite each other on the outer side of the rotor cup, each forming an air gap.The rotor cup has armatures arranged circumferentially around the axis of rotation of the electric motor on its outer surface in such a way that at least one of the armatures can magnetically lock with the two pole shoes of the electromagnet to potentially provide cogging torque protection. To hold the rotor cup in a rotor holding position, a first short current pulse can be impressed into the coil assembly by means of a circuit arrangement of the actuator, such that a residual magnetic field remains in the coil core to provide the magnetic cogging torque protection. To release the rotor cup into a rotor freewheeling position, a second short current pulse can be impressed into the coil assembly by means of the same circuit arrangement, such that the residual magnetic field remaining in the coil core is substantially dissipated, thus dissolving the magnetic cogging torque protection.

[0017] In such actuators, the flap or valve is moved around an axis by the actuator's actuating element, or even at least partially formed directly by it. The actuator is often configured to move the actuating element from a first position to a second position. Both positions can also be end stops. The first position can also be called the rest position, to which the actuator returns the actuating element when the drive element (i.e., the electric motor) is de-energized, particularly by means of a pre-tensioned return spring. Such actuators are also referred to as fail-safe actuators. The second position can be called the actuating position. The actuator's connection can be set within a predetermined range of angles or rotations between the rest position (or first position) and the actuating position.The second position is rotatable around its axis. The maximum angle of rotation between these two positions is typically 90° ± 10°.

[0018] To keep a fail-safe actuator in the actuated position, the simplest solution is to maintain the electric motor in this position using a continuously applied holding current (minimum current). Only when the power supply, and thus the holding current, fails does the spring compress, and the actuator moves the actuator to its safe rest position. However, the solution described above results in a relatively high power consumption in the actuated position. For example, the duty cycle of safety-relevant fire dampers is effectively 100% (ED 100%).

[0019] In the case of non-fail-safe actuators, electric motors with increased self-holding torque are often required to prevent the actuator from "continuing to run" beyond the applied torque of the load, i.e., the connected flap or valve. The electric motors designed for this purpose typically feature a rotor with a detent gear.

[0020] From WO 2011 / 047488 A1, a brushless DC motor is known which is suitable for driving an actuating element of an actuator. The DC motor described therein comprises a stator, a rotor cup rotating around the stator with several permanent magnet poles, and a cogging torque plate connected to the stator with several pole shoes for generating a cogging torque that moves the rotating rotor cup into a detent position. In the detent position, the pole shoes are arranged between two adjacent poles of the rotating rotor cup to form a magnetic short circuit. The cogging torque plate is essentially located outside the rotating magnetic field generated by the stator during operation, thus decoupling the generation of the cogging torque from the electrical behavior of the brushless DC motor.

[0021] The actuators under consideration can also be linear actuators, which effect a linear positioning movement of the actuating element along an actuating axis at the actuator connection, for example to control a valve to open, partially open, or close. The rotary movement at the actuator connection can be converted into a corresponding linear movement, for example, by means of a rack, a spindle, or an eccentric.

[0022] Summary of the invention

[0023] Based on the aforementioned prior art, it is an object of the present invention to provide a structurally simpler device for providing an electrically adjustable, non-contact magnetic cogging torque lock.

[0024] A further object of the invention is to provide an alternative to the devices according to the prior art.

[0025] A further object of the invention is to provide an (extended) electric motor with a device according to the invention.

[0026] Furthermore, it is an object of the invention to provide a first and second retrofit unit for retrofitting an electrically adjustable and contactless magnetic cogging torque damping system to an internal rotor electric motor or an external rotor electric motor of the prior art.

[0027] A further object is to specify an arrangement comprising such an electric motor, an internal rotor electric motor with such a first retrofit unit attached thereto, or an external rotor electric motor with such a second retrofit unit attached thereto, and a circuit arrangement in each case. Finally, it is an object of the present invention to specify a first and second actuator with such an arrangement.

[0028] The object of the invention is achieved by the features of the independent claims. Advantageous embodiments are specified in the dependent claims.

[0029] In the inventive device, the two magnetic field conductors each form a plurality np of finger-shaped sections, each with a finger end piece. The finger ends are designed and aligned in a radial outer region of the electro-permanent magnet such that the finger ends of one of the two magnetic field conductors engage between the finger ends of the other magnetic field conductor to form a plurality nps of stator pole shoes with north and south poles alternating circumferentially with respect to the axis of rotation.

[0030] The interlocking, finger-shaped sections of the two magnetic field conductors typically do not touch. In other words, the interlocking, finger-shaped sections of the two magnetic field conductors are arranged with a gap between them. Furthermore, the interlocking, finger-shaped sections of the two magnetic field conductors, and thus both magnetic field conductors, are rotationally fixed and, in particular, rigidly connected to one another with respect to the axis of rotation of the device according to the invention. Specifically, the interlocking, finger-shaped sections of the two magnetic field conductors lie in a common plane. All previously described components of the electro-permanent magnet are rotationally fixed and, in particular, rigidly connected to one another when assembled. The previously described components can, for example, be glued and / or snapped together.

[0031] The device proposed here comprises an electro-permanent magnet, which includes two highly permeable magnetic field conductors (sheet metal) with finger-shaped sections that interlock similarly to the stator of bicycle claw pole generators, enclosing the magnetic core and the coil arrangement like a cage.

[0032] The object of the invention here, however, is not to generate electricity for bicycle lighting, but to provide an electrically adjustable, contactless magnetic cogging torque mechanism between the electro-permanent magnet (stator) and the cogging torque ring (rotor). The cogging torque ring is made of a soft magnetic material. Suitable soft magnetic materials include iron, steel, cobalt, nickel alloys, or ferrites, which are easily magnetized in a magnetic field. In particular, the cogging torque ring is made of electrical steel. Polarization in all soft magnetic materials leads to a magnetic flux density many times higher than that generated by an externally applied magnetic field in air. The magnetic materials under consideration preferably have a permeability of p. rof at least 40, in particular of at least 300. Preferably, the two magnetic field conductors are made of electrical steel, in particular of non-grain-oriented electrical steel, which is also suitable for punching and bending.

[0033] The great advantage of the invention lies in the simple design of the device with two, typically identical, stamped / bent parts made of magnetically conductive sheet metal, whose radial finger end pieces interlock to form alternating north and south poles in the circumferential direction.

[0034] A pole shoe is a component made of a material with high magnetic permeability, such as iron or electrical steel. The pole shoe serves to direct and distribute the magnetic field lines of a permanent magnet in a defined shape. In an electric motor, for example, the magnetic excitation field is distributed across the armature in a circular segment shape by a pole shoe to homogenize the magnetic flux density along the armature's rotation. In electrical engineering, the armature refers to the electrically active part of the rotor. Not only the stator, but also the armature or rotor of electric motors and generators have pole shoes.

[0035] In electrical engineering, electrical coils are windings and wound components suitable for generating or detecting a magnetic field. The coil arrangement described in the context of the invention comprises, in particular, one or two coils, preferably one or two ring-shaped coils made of wound insulated wire, such as copper wire. Depending on the winding direction and the polarity of a current impressed by the respective winding, a magnetic field with one of two possible magnetic field directions is formed, wherein the generated electromagnetic field is perpendicular to the plane of the coil.

[0036] An electropermanent magnet is a special type of magnet whose external magnetic effect can be switched on and off by an electric current pulse. Electropermanent magnets are classified as either compensated or uncompensated. In the compensated case, they are also referred to as double magnet systems.

[0037] Such a compensated electro-permanent magnet comprises an electromagnet with a core made of magnetically "semi-hard" material and a permanent magnet made of a magnetically "hard" material. If the semi-hard core is magnetized in the opposite direction to the hard core, their magnetic effects cancel each other out. If the semi-hard core is magnetized in the same direction as the permanent magnet, a magnetic effect is present. This is a so-called bistable magnet, in which electrical energy is only required to switch between the two states.

[0038] Uncompensated electro-permanent magnets, on the other hand, only have a magnetic core made of a magnetically "semi-hard" material. They inherently exhibit a lower maximum magnetic field strength or flux density than compensated electro-permanent magnets. However, continuously variable intermediate levels between the maximum field strength and a negligible residual magnetic field strength can be set by appropriately selecting a current pulse through the electric coil(s).

[0039] The electrical adjustment of the holding torque ultimately acting on the detent ring depends on the electrical energy of a current impressed into the coil assembly up to a magnetic saturation limit of the enclosed magnetic core. The holding torque is essentially proportional to the magnetic induction present at the stator pole shoes, which originates from the remanent magnetic field of the magnetic core when the current is switched off and is conducted to the stator pole shoes via the two magnetic field conductors. If the current intensity of a current impressed into the coil assembly is constant, the electrical energy, and thus also the effective magnetic induction at the stator pole shoes, and consequently the holding torque, can be adjusted via the pulse length of a current pulse.To reduce the holding torque, a current with the opposite sign can be impressed into the coil arrangement to weaken the remanent magnetic field in the magnetic core, such that a coercive field strength Kc characteristic of the magnetic material used is exceeded. The holding torque can be adjustable, for example, in a range from 0% to 100%, where 100% refers to a saturated maximum induction value after the current excitation is removed. The object of the invention is further achieved by an (extended) electric motor comprising a stator, a rotor rotatably arranged about an axis of rotation of the electric motor, and a device according to the invention for providing the electrically adjustable, contactless magnetic cogging torque between an electro-permanent magnet and a cogging torque ring rotatably arranged about the axis of rotation of the electric motor.The cogging torque ring is rotationally fixed to the rotor of the electric motor or forms such a cogging torque ring. A main structural axis of both the cogging torque ring and the electro-permanent magnet is aligned with the axis of rotation of the electric motor. The cogging torque ring is arranged axially outside the stator. The electro-permanent magnet is axially adjacent to the stator of the electric motor. The cogging torque ring and the electro-permanent magnet are axially aligned such that the rotor pole shoes of the cogging torque ring are opposite the stator pole shoes of the electro-permanent magnet. An air gap, typically in the range of 0.1 mm to 2 mm, forms between the rotor pole shoes and the stator pole shoes.

[0040] The object of the invention is further achieved by a first retrofit unit for retrofitting an electrically adjustable, contactless magnetic cogging torque damper to an external rotor electric motor. The cogging torque ring of the device can be mounted in a rotationally fixed manner on an axial outer surface of a rotor of the external rotor electric motor, such that a structural main axis of the cogging torque ring is aligned with the axis of rotation of the external rotor electric motor. Preferably, the device according to the invention – as with the first retrofit unit – can be mounted on an outer surface axially opposite the mounting side of the electric motor for fastening to a base or support plate or to an intermediate circuit carrier.

[0041] The first retrofit unit features a fixed mounting device, such as a bracket or crossbar, that extends over the rotor and is positioned relative to the stator of the external rotor electric motor. The electro-permanent magnet of the device is attached to this mounting device so that its main axis aligns with the axis of rotation of the external rotor electric motor, and so that the stator pole shoes of the electro-permanent magnet are radially opposite the cogging ring with the rotor pole shoes.

[0042] The object of the invention is further achieved by a second retrofit unit for retrofitting an electrically adjustable, non-contact magnetic cogging torque limiter to an internal rotor electric motor. The electro-permanent magnet of the device can be fixedly attached to an axial outer surface of a stator of the internal rotor electric motor, such that a main structural axis of the electro-permanent magnet is aligned with the axis of rotation of the internal rotor electric motor. Preferably, the device according to the invention can be attached to the axial outer surface opposite a mounting side of the electric motor. The cogging torque ring of the first retrofit unit is connected via a connecting element, such as...The motor shaft of the internal rotor electric motor can be connected in a rotationally fixed manner via struts, spokes, or a disc. The motor shaft extends axially through a through-hole in the electro-permanent magnet and projects axially through the motor shaft. The cogging torque ring of the first retrofit unit is axially alignable so that the cogging torque ring with the rotor pole shoes is radially opposite the stator pole shoes of the electro-permanent magnet.

[0043] The object of the invention is further achieved by an arrangement comprising such an (extended) electric motor, an external rotor electric motor with such a first retrofit unit attached thereto, or an internal rotor electric motor with such a second retrofit unit attached thereto, and each of these, a circuit arrangement. The latter comprises a control unit, such as a microcontroller, and at least two switching elements, such as switching transistors, that can be controlled by the control unit. To hold the detent ring in a holding position, a first current pulse can be impressed by the control unit into the at least one electrical coil of the electro-permanent magnet via the at least two switching elements, so that subsequently a remanent magnetic field still present in the electro-permanent magnet, acting on the stator pole shoes of the electro-permanent magnet, remains to provide the magnetic detent torque damping.To release the cogging torque ring in a freewheeling operation, a second current pulse can be impressed into the at least one electrical coil via the at least two switching elements of the circuit arrangement, so that subsequently the remanent magnetic field still present in the electro-permanent magnet, acting on the stator pole shoes to overcome the magnetic cogging torque inhibition, is essentially reduced.

[0044] The term "essentially reduced" here means that the magnetic induction value of the reduced reference magnetic field is at most 0.1 times, preferably at most 0.05 times, the magnetic induction value of the remanent magnetic field remaining after the first short-term current pulse. If the current of a current that can be impressed into the coil arrangement by the circuit arrangement is constant, the electrical energy, and thus also the magnetic induction value at the stator pole shoes and consequently the holding torque, can be adjusted via the pulse length of a current pulse. The holding torque can be adjustable in a range from 0% to 100%, with the 100% referring to a saturated maximum induction value. Setting a predetermined value for the cogging torque, which corresponds to a predetermined torque value for the holding torque, can, for example, be done in the form of a setpoint value that the control unit of the circuit arrangement can, for example, define.received via an interface.

[0045] Furthermore, the problem is solved by a first actuator comprising an arrangement according to the invention, in particular a reduction gear connected downstream of the electric motor, as well as an output-side actuating element with an actuating connection.

[0046] According to the invention, the control unit is configured to receive a control signal and to correspondingly control the electric motor to move the actuator from a predetermined first position to a predetermined second position and vice versa. The first and second positions can optionally be adjustable end stops of the first actuator. The control unit is also configured to control the at least two switching elements for controlling the electro-permanent magnet in such a way that the actuator for moving the actuator from the first position to the second position or from the second position to the first position switches from a holding mode to a freewheeling mode when the electric motor is activated, particularly shortly before or after the electric motor is activated.Furthermore, the control unit is designed to control at least two switching elements for the control of the electro-permanent magnet in such a way that the actuator switches from freewheeling operation to holding operation upon reaching the second or first position, in particular shortly before or after reaching the second or first position.

[0047] The control unit can be, for example, a higher-level microcontroller of the actuator. The control signal can be received, for example, via a connection cable from the actuator or wirelessly from a higher-level control unit. Alternatively, the control signal can also be generated by the control unit itself, for example, depending on the time of day, the day of the week, or the temperature. This embodiment is particularly advantageous for non-fail-safe actuators.

[0048] Due to the time-coordinated change from holding mode to freewheeling mode and back, a cogging torque wheel is advantageously not required for the operation of the actuating element.

[0049] Another advantage is that the elimination of the detent torque in freewheel operation prevents disruptive mechanical vibrations that can be adversely transmitted as acoustic structure-borne noise through the entire drive train into the connected valve or flap and then further into a connected pipe system or ventilation duct.

[0050] Finally, the problem is solved by a second actuator, which comprises an arrangement according to the invention, in particular a reduction gear downstream of the electric motor and an output-side actuating element with an actuating connection.

[0051] The actuator has a return spring to provide a return torque acting on the actuator, automatically moving the actuator to a safe rest position. This occurs particularly when the power supply to the actuator fails or when a switch-off signal is received, moving the actuator to its safe rest position. The return torque directly, or indirectly if a reduction gear is present, causes a rotor return torque on the electric motor. The control unit is configured to activate the electric motor when the power supply is switched on or when a switch-on signal is received, moving the actuator from its safe rest position to an actuated position.The control unit is also designed to control the at least two switching elements in such a way that the actuator switches from a freewheeling operation to a holding operation upon reaching the actuating position, in particular shortly before or after reaching the actuating position.

[0052] For the first and second actuators, "shortly before reaching" or "shortly after reaching" refers to a time span of less than 3 seconds, and in particular less than 1 second.

[0053] The holding torque applied to the rotor of the electric motor by means of the electro-permanent magnet during holding operation is greater than the total rotor torque acting on the rotor, in particular at least 1.1 to 3 times greater. This ensures that the actuator remains reliably in the actuated position even when considering connected loads such as flaps or valves. The load torque acting on the actuator connection due to the connected flap or valve is generally assumed to be known.

[0054] The control unit is further configured to control at least two switching elements of the circuit arrangement upon receipt of a switch-off signal or upon failure of the power supply in such a way that the actuator switches from holding mode to freewheeling mode, whereby the actuating element then automatically returns from the actuating position to the safe rest position.

[0055] The shutdown signal can originate from a higher-level control unit and be received, for example, via the actuator's connection cable or wirelessly by the control unit. Alternatively, the circuit arrangement can be configured such that the actuator automatically switches from holding mode to freewheeling mode when the power supply fails, allowing the actuator to subsequently return to its safe rest position.

[0056] In this context, "electric motor" refers to the first and second actuators, specifically the electric motor according to the invention or an enhanced version thereof, featuring an integrated, electrically adjustable, and contactless magnetic cogging torque damping system, as well as an internal rotor electric motor as a unit or an external rotor electric motor as a unit to which a first or second retrofit unit is attached. The internal and external rotor electric motors are commercially available electric motors of the prior art.

[0057] Both actuators described above preferably, but not necessarily, have a reduction gear. In other words, the (extended) electric motor, the internal and external rotor electric motor of the prior art for direct drive can be directly connected to the actuator terminal.

[0058] The major advantage of the invention lies in the fact that the two actuators described above require a significantly lower average electrical power in holding mode, i.e., in the actuating position or in the first or second positioning position, and thus, from this perspective, for the majority of the time. Accordingly, the overall current or energy consumption is reduced over the operating time of the first and second actuators.

[0059] Another major advantage is that, for both actuators, when a reduction gear is present, only a relatively small holding force of less than 1 N, in particular less than 0.1 N, is required to securely hold the actuator's actuating element in the actuated position, due to the typically very high gear reduction in the range of 1:500 to 1:25000 and the cogging torque acting radially on the outer surface of the electric motor's rotor. For this purpose, the reduction gear has a reduction ratio in the range of 1:500 to 1:25000, preferably 1:1000 to 1:10000.

[0060] The reduction gear typically includes several gears connected in series, particularly those mounted on the base plate, to achieve the desired reduction of an actuating element of the first or second actuator. The actuating element can be, for example, a gear segment. The actuating element itself has an actuator port for connecting the actuator to a flap or valve as a load. Depending on the design of the output, a predefined rotary movement about an actuator axis or a predefined linear movement along the actuator axis is possible at the actuator port.

[0061] The coil arrangement can generally comprise a single coil or winding wound around the magnetic core, which can then be energized by means of an excitation current with a positive and negative polarity. Alternatively, the coil arrangement can also comprise two coils or windings wound around the magnetic core, which can be controlled separately with an excitation current.

[0062] In particular, the actuators described above comprise a housing for accommodating the following actuator components: an extended electric motor with an integrated adjustable cogging torque limiter, or an external or internal rotor electric motor with an axially retrofitted first or second retrofit unit containing such an adjustable cogging torque limiter, a reduction gear (if present), and an actuating element. The components are preferably arranged on a base or support plate within the actuator housing.

[0063] Embodiments of the invention

[0064] According to one embodiment of the device, the electro-permanent magnet comprises, with respect to its main structural axis, a straight prismatic or straight hollow prismatic, in particular a cylindrical or hollow cylindrical, magnetic core. The electro-permanent magnet further comprises at least one electrical coil coaxially surrounding the magnetic core, and two, preferably identical, magnetically conductive sheet metal parts serving as magnetic field conductors. The two sheet metal parts enclose or surround the magnetic core with the at least one electrical coil, axially opposite each other with respect to the main structural axis. Both sheet metal parts are magnetically connected to one of the poles of the magnetic core by means of a radially inner central sheet metal section. In other words, the two sheet metal parts, with their central sheet metal section, lie close and preferably flush against the poles of the magnetic core without forming an air gap. The two sheet metal parts can, for example, be made of a spherical or spherical material.The two sheet metal parts are glued, clamped, soldered, or welded to the magnetic core. They form the plurality np of finger sections extending radially outwards from the core. The two sheet metal parts are arranged circumferentially relative to the main axis of the structure, specifically with a gap, such that the finger ends of one sheet metal part engage between the finger ends of the other sheet metal part, particularly without contact. The axis of rotation of the device and the main axis of the electro-permanent magnet are aligned. This coaxial design results in a conveniently simple and easy-to-manufacture assembly.

[0065] In one embodiment, the finger ends of the two sheet metal parts are bent axially towards each other in the direction of the main axis of the electro-permanent magnet to form the circumferentially distributed stator pole shoes on the radial outer surface of the outer region. The interlocking finger ends lie in a common, radially outer plane. The stator pole shoes are arranged radially opposite the cogging ring with the rotor pole shoes. In particular, the finger ends are bent by 90° ±10° so that their surface normals run perpendicular to the main axis of the electro-permanent magnet. The finger ends are more or less flat and preferably flat. Both sheet metal parts can advantageously be manufactured by a stamping and bending process.

[0066] Depending on the design of the magnetic flux guidance, in the locked state, each rotor pole shoe is radially opposite each stator pole shoe, or each rotor pole shoe is positioned circumferentially exactly between two stator pole shoes and radially opposite them. In the latter case, the rotor pole shoes are spaced apart circumferentially with respect to the axis of rotation.

[0067] In an alternative embodiment to the previous embodiment, the finger-shaped sections of one of the two sheet metal parts, together with their finger ends, extend radially towards the radial outer surface. The finger-shaped sections and finger ends lie together in a common, axially outer plane. The surface normals of the finger-shaped sections and finger ends run parallel to the main structural axis of the electro-permanent magnet. This first sheet metal part is thus a more or less planar sheet metal part. It can advantageously be manufactured simply by means of a stamping process.

[0068] The finger-shaped sections of the other sheet metal part, in contrast, each have a central finger segment bent axially towards the main axis of the electro-permanent magnet, with the adjacent finger end segments bent radially towards the main axis of the electro-permanent magnet to form the circumferentially distributed stator pole shoes together with the finger end segments of the first sheet metal part. In this case, the central finger segments, together with the finger end segments, encircle the radial outer region of the electrical coil. The finger end segments of the second sheet metal part are thus doubly bent in the same direction, specifically by 90° ±10°, and therefore encircle the radial outer surface of the electrical coil of the electro-permanent magnet. The stator pole shoes are arranged axially opposite the cogging ring with the rotor pole shoes.The finger ends of the first and second sheet metal parts thus lie more or less in a common plane, preferably in a common plane. The normal to this plane runs parallel to the main structural axis of the electro-permanent magnet.

[0069] Depending on the design of the magnetic flux guidance, in the locked state either one rotor pole shoe is axially opposite each stator pole shoe, or one rotor pole shoe is positioned circumferentially exactly between two stator pole shoes and axially opposite them. In the latter case, the rotor pole shoes are again spaced apart circumferentially with respect to the axis of rotation.

[0070] Preferably, the electrical coil is circular or polygonal and spans a coil plane, wherein the main constructive axis of the electro-permanent magnet runs perpendicularly through the coil plane, in particular in the middle.

[0071] The previously considered finger-shaped sections of the two sheet metal parts preferably taper towards the radial end.

[0072] In one embodiment of the device, the electro-permanent magnet has a (straight) hollow prismatic, in particular a hollow cylindrical, permanent magnet ring. The permanent magnet ring coaxially surrounds the at least one electrical coil or the coil arrangement. The permanent magnet ring is made of a magnetic material with a remanent flux density BR of at least 0.5 T, in particular at least 0.7 T, and with a coercive field strength Kc of more than 100 kA / m, in particular at least 500 kA / m. Such a permanent magnet ring exhibits hard magnetic properties and is virtually unaffected by magnetic interference fields in the vicinity of the permanent magnet. Hard magnetic materials include, for example, alloys of cobalt-samarium or neodymium-iron-boron.

[0073] When the coil assembly of such an electro-permanent magnet is appropriately energized, an electromagnet with the corresponding sign is induced in the semi-hard magnetic core, depending on the sign of the applied current. After the applied current is removed, an axially oriented remanent magnetic field remains in the core. This field is superimposed on an axially oriented permanent magnetic field of the permanent magnet ring in the respective radially inner, central section of the two laminations, acting as a magnetic field conductor. If the two magnetic fields are additive, alternating north and south poles form at the finger ends in the circumferential direction around the main axis of the design. Otherwise, the two magnetic fields cancel each other out, so that no north and south poles with significant magnetic field strength form at the finger ends.This embodiment has the advantage that higher magnetic induction values ​​can be achieved at the stator pole shoes compared to an electro-permanent magnet with only the "semi"hard magnetic core.

[0074] According to a further embodiment of the device, the magnetic core of the electro-permanent magnet is made of a magnetic material with a remanent flux density BR of at least 1 T, in particular of at least 1.2 T, and with a coercive field strength Kc in the range of 25 kA / m to 100 kA / m, in particular in a range of 40 kA / m to 100 kA / m, and / or with a magnetic energy density BH ma x of at least 30 kJ / m 3manufactured. Such "semi"hard magnetic materials include, for example, alloys of aluminum-nickel-cobalt, in particular AINiCo 600, or alloys of platinum-cobalt, copper-nickel-iron, copper-nickel-cobalt, iron-cobalt-chromium, or manganese-aluminum-carbon. A magnetic core made of such a magnetic material is advantageously able to provide a very strong remanent magnetic field at its two poles, the magnetic induction of which can be adjusted.

[0075] According to one embodiment of the device, the two magnetic field conductors are made of a magnetic material with a permeability number p. rof at least 40, in particular at least 300. Preferably, the two magnetic field conductors are made of electrical steel, in particular of non-grain-oriented electrical steel or of dynamo steel, each of which is also suitable for punching and bending. Electrical steel, in particular non-grain-oriented electrical steel, is described, for example, in EN 10106 "Cold-rolled non-grain-oriented electrical steel and strip in the annealed condition".

[0076] In one embodiment of the arrangement according to the invention, the electro-permanent magnet has two electrical coils, with a voltage detection unit connected to the control unit in parallel to one of these electrical coils for detecting a voltage signal. The control unit is configured to analyze the voltage signal for the presence of repetitive voltage pulses and to output these as rotational pulses, such as in the form of digital square waves. Control and regulation of an electric motor connected to the arrangement according to the invention is possible based on such rotational pulses.

[0077] According to one embodiment, the arrangement includes a magnetic field sensor, in particular a Hall sensor, located in the region of the stator pole shoes of the electro-permanent magnet for detecting a magnetic induction value. The control unit is configured to control the at least two switching elements of the circuit arrangement to induce the first current pulse with a first predetermined pulse length, to detect the current magnetic induction value after its termination, and, if the detected magnetic induction value does not exceed a predetermined upper limit, to repeatedly induce the first current pulse with an increasingly longer first pulse length until, after its termination, a current magnetic induction value exceeds the predetermined upper limit.

[0078] This makes it advantageously possible to monitor the electro-permanent magnet in such a way that the upper limit of the magnetic induction of the remanent magnetic field acting on the stator pole shoes of the electro-permanent magnet is reliably reached, in order to then securely hold the rotor of the electric motor in holding mode, which is connected to the cogging torque ring in a rotationally fixed manner.

[0079] Alternatively or additionally, the control unit can be configured to control at least two switching elements of the circuit arrangement to imprint the second current pulse with a second predetermined pulse length, to detect a current magnetic induction value after its termination, and, in the event that the detected magnetic induction value does not fall below a predetermined lower limit, to repeatedly imprint the second current pulse with an increasingly longer second pulse length until, after its termination, a current magnetic induction value falls below the predetermined lower limit.

[0080] This makes it advantageously possible to monitor the electro-permanent magnet in such a way that the lower limit of the magnetic induction of the remanent magnetic field acting on the stator pole shoes of the electro-permanent magnet is not exceeded, in order to then safely release the rotor of the electric motor, which is connected to the cogging torque ring in free-running operation.

[0081] In particular, the lower limit of magnetic induction lies in a range of 0.05 to 0.2 times the upper limit of magnetic induction.

[0082] Exemplary embodiments of the drawing

[0083] The invention and advantageous embodiments of the present invention are explained with reference to the following figures. These show:

[0084] FIG 1 shows side-by-side components of an electro-permanent magnet of an exemplary device according to the invention for providing a contactless magnetic cogging torque inhibition,

[0085] FIG 2 shows a top view of an exemplary device according to the invention, as shown in FIG 3 in the direction of view II.

[0086] FIG 3 shows the example according to FIG 2 in a sectional view through a constructive main axis of the device according to the invention,

[0087] FIG 4 shows a side view of an electro-permanent magnet as a coaxially internal part of the device according to the invention.

[0088] FIG 5 shows a sectional view through a rotational axis of an electric motor, for example designed as an external rotor, with an integrated device of this type arranged on a base plate of an actuator according to the invention.

[0089] FIG 6 shows a sectional view along the section line Vl-Vl shown in FIG 5 through the electric motor with integrated device according to the invention, FIG 7 shows a sectional view through a rotational axis of an electric motor, by way of example designed as an internal rotor, with such an integrated device according to the invention,

[0090] FIG 8 shows a sectional view through a rotational axis of an electric motor designed as an external rotor with an axially subsequently attached first retrofit unit with such a device according to the invention,

[0091] FIG 9 shows a sectional view through a rotational axis of an electric motor designed as an internal rotor with a second retrofit unit axially attached with such a device according to the invention.

[0092] FIG 10 shows side-by-side components of an exemplary electro-permanent magnet according to an embodiment of the device according to the invention, additionally with a permanent magnet ring and a magnetic insulator.

[0093] FIG 11 shows a sectional view through a constructive main axis of the exemplary electro-permanent magnet according to FIG 10,

[0094] FIG 12 shows the principle of a circuit arrangement for selectively controlling the electro-permanent magnet according to the invention for a possible holding or releasing of the rotor of an electric motor,

[0095] FIG 13 shows the principle of a second circuit order with a coil arrangement comprising two electrical coils and a magnetic field sensor, and

[0096] FIG 14 shows the principle of a third circuit order with a coil arrangement in a full bridge, with a magnetic field sensor and with a voltage sensing unit for providing rotational pulses.

[0097] Detailed description of the exemplary implementations

[0098] FIG 1 shows components Bu, SP, MK, Bo of an electro-permanent magnet MAG of an exemplary device RH according to the invention for providing a contactless magnetic cogging torque damping system. In the left and right parts of FIG 1, an upper sheet metal part Bo and a lower sheet metal part Bu are shown as magnetic field conductors. The designation as upper and lower sheet metal part Bo, Bu is used solely for the purpose of illustrating these parts in the following figures. Alternatively, the two sheet metal parts Bo, Bu can also be referred to as the first and second sheet metal part. Both sheet metal parts Bo, Bu have, by way of example, twelve radially projecting finger-shaped sections Fo, Fu, which are evenly distributed around the circumference of a main structural axis A of the electro-permanent magnet MAG. As shown by the dashed lines, some finger-shaped sections Fo, Fu may also be omitted.Figure 1 shows the two sheet metal parts Bo and Bu with the finger-shaped sections Fo and Fu, initially without any bends. OF denotes a central through-opening, and Zu and Zo denote a central sheet metal section located radially inside the main structural axis A. Eo and Eu denote radially outside finger ends, and Ao and Au denote the finger bases. The latter adjoin the respective radially inside central sheet metal section.

[0099] Another example of a hollow cylindrical magnetic core, MK, is shown. Its two axial outer faces each face an inner central sheet metal section, Zo, Zu, and are in contact with these sections. The two axial outer faces of the magnetic core MK form pole ends, at which a magnetic north pole and south pole, and vice versa, are formed in the magnetized state. The magnetic core MK is coaxially enclosed on the outside by an electrical coil arrangement SP. For this purpose, the electrical coil arrangement SP has a geometrically adapted opening OFS. EA denotes two electrical connections of the electrical coil arrangement SP.

[0100] In the assembled state, i.e., with the finger ends Eo and Eu bent, the two sheet metal parts Bo and Bu then cage-like enclose the intervening electrical coil assembly SP, the latter of which in turn coaxially accommodates the magnetic core MK. The finger ends Eo of the upper sheet metal part Bo engage between the finger ends Eu of the lower sheet metal part Bu. All previously described components Bo, Bu; SP, MK of the electro-permanent magnet MAG are then, in the assembled state, rotationally fixed and, in particular, firmly connected to one another. The previously described components Bo, Bu; SP, MK can, for example, be glued and / or snapped together.

[0101] FIG. 2 shows a top view of an exemplary device RH according to the invention, as shown in the view direction II in FIG. 3. The permanent magnet MAG is arranged radially inside, and a detent ring RR is arranged radially outside and around a common axis of rotation D. Reference numeral W denotes a shaft that is aligned with the axis of rotation D of the device RH. In the example of FIG. 2, a shaft W aligned with the axis of rotation D is rotatably connected to the detent ring RR. The shaft W, or motor shaft, can also be part of an electric motor (see FIG. 5 to FIG. 9). The detent ring RR comprises, by way of example, 24 rotor pole shoes PR, arranged radially inwards and evenly distributed circumferentially around the axis of rotation D. Between these are 24 grooves NU or recesses.

[0102] The finger end pieces Eo, Eu of the electro-permanent magnet MAG are designed and aligned in a radial outer region RAB of the electro-permanent magnet MAG such that the finger end pieces Eo, Eu of one of the two sheet metal parts Bo, Bu engage between the finger end pieces Eu, Eo of the other sheet metal part Bu, Bo to form a number nps of stator pole shoes PS, which, in this example, also represent 24 stator pole shoes PS, with alternating north and south poles N, S circumferentially around the axis of rotation D. The finger-shaped sections Fu of the lower sheet metal part Bu are hatched and dashed. The respective corresponding finger end pieces Eu each form a south pole S as pole shoes PS, while the finger end pieces Eo of the upper sheet metal part Bo each form a north pole N as pole shoes PS. In this example, the rotor pole shoes PR, when locked in the engaged state, are each directly opposite one stator pole shoe PS of the electro-permanent magnet MAG, forming an air gap LS.Finally, AD denotes the outer diameter of the inventive device RH and the detent ring RR.

[0103] FIG. 3 shows the example according to FIG. 2 in a sectional view through a main structural axis A of the device RH according to the invention. HE denotes the component height of the device RH according to the invention and of the electro-permanent magnet MAG, and MD denotes the outer diameter of the electro-permanent magnet MAG. The ratio between the outer diameter MD and the component height HE is particularly in the range of 3 to 20, preferably in the range of 5 to 10. Furthermore, the central through-opening OF, which is provided for guiding a shaft W, such as a motor shaft of an electric motor, through it, can be seen in the example of FIG. 3. This through-opening OF is not strictly necessary, as shown, for example, in the following FIG. 8. The representation in FIG. 3 also shows how the angled finger end pieces Eo, Eu of the finger-shaped sections Fo, Fu connect the electric coil SP or the electric coil.The coil arrangement is enclosed at the radial outer edge to form the respective pole shoes PS. The corresponding finger attachments, designated Ao and Au, are located on the respective radially inner central sheet metal sections Zo and Zu. These latter sections rest on the axial outer sides of the magnetic core MK as pole ends PE. FIG. 4 shows a side view of an electro-permanent magnet MAG as a coaxially inner part of the inventive device RH. In this illustration, the finger end pieces Eo and Eu, bent by 90° as an example, can be seen, which also taper trapezoidally towards their respective ends. The sequence of north and south poles N and S, which form on the stator pole shoes PS when the magnetic core MK is magnetized, is also clearly visible.

[0104] FIG 5 shows a sectional view through a rotational axis D of an electric motor MO, exemplarily designed as an external rotor motor, with an integrated device RH arranged on a base plate GP of an actuator according to the invention. The electric motor MO, extended by the function of cogging torque damping, comprises a rotational axis D aligned with the main structural axis A, about which a motor shaft W of the electric motor MO rotates. A motor gear MZ is rotationally fixed to the motor shaft W, which drives further gears ZR of a reduction gear G of the actuator, only partially shown. AM denotes an axial outer surface of the electric motor MO. A circuit carrier LP is arranged on the base plate GP, on which a control unit MC, in particular a microcontroller, for controlling the actuator, as well as a control unit TR for the electric motor MO and optionally for the cogging torque damping, are arranged.The control unit TR typically comprises integrated power semiconductors such as FETs or diodes. Additional components, such as Hall sensors for the magnetic detection of the rotational movement of the rotor RO of the electric motor MO, can be arranged on the circuit carrier LP. Besides the rotor RO, which drives the motor shaft W, the electric motor MO includes a stator ST, which is stationary relative to the base plate GP. The rotor MO, with its permanent magnets PM distributed circumferentially around the axis of rotation D, can rotate around the stator ST. For clarity, the associated excitation coils of the stator ST are not shown. H denotes the axial height of the electric motor MO, and DM denotes the corresponding motor diameter.

[0105] According to the invention, the electric motor MO comprises an integrated device for providing an electrically adjustable, non-contact magnetic cogging torque lock between an electro-permanent magnet MAG and a cogging torque ring RR rotatably arranged about the axis of rotation D of the electric motor MO. The latter is rotationally fixed to the rotor RO of the electric motor MO. The present figure illustrates two possible embodiments of the cogging torque ring RR or cogging torque wheel. In the left half of FIG. 5, the cogging torque ring RR is arranged in an axial extension of the rotor RO, which is designed as a rotor housing, for example, by being pressed in or glued in place. In the right part of FIG. 5, the rotor RO or the rotor housing itself forms the cogging torque ring RR. This can be achieved, for example, by means of a press-in tool acting radially from the outside on the outer surface ROA of the rotor RO, which then presses the rotor pole shoes PR into the interior of the rotor RO.The cogging torque ring RR itself is arranged axially outside the stator ST. Furthermore, the electro-permanent magnet MAG is axially connected to the stator ST of the electric motor MO, for example, by adhesive bonding. A magnetic insulator Ml, such as a perforated disc made of plastic or aluminum, can be arranged between the stator ST and the electro-permanent magnet MAG for magnetic decoupling. The cogging torque ring RR and the electro-permanent magnet MAG are also axially aligned such that the rotor pole shoes PR of the cogging torque ring RR are radially opposite the stator pole shoes PS of the electro-permanent magnet MAG. Finally, L denotes a lead wire that connects the electrical coil SP or coil assembly in the electro-permanent magnet MAG to the circuit carrier LP. A suitable current pulse for electrically adjusting the magnetic cogging torque is then applied via this lead wire L.In the simplest case, such an electric motor MO can be blocked in its rotational movement or switched to freewheel mode without effective cogging torque damping.

[0106] FIG. 6 shows a sectional view along the section line Vl-Vl shown in FIG. 5 through the electric motor MO in FIG. 5 with integrated device RH according to the invention. In this view, the radial fitting of the cogging torque ring RR into the inside of the rotor RO is clearly visible. Also visible is the through-opening OF in the electro-permanent magnet MAG for the possible passage of the motor shaft W to drive the rotor RO.

[0107] FIG. 7 shows a sectional view through a rotational axis D of an exemplary internal rotor electric motor MO with an integrated device RH according to the invention. In contrast to the two previous figures, FIG. 5 and FIG. 6, the rotor RO is located coaxially inside with respect to the rotational axis D, and the stator ST is located coaxially outside. MG denotes a motor housing that is stationary with respect to the receiving circuit carrier LP. The electro-permanent magnet MAG is attached to the axial end of the stator ST. The cogging torque ring RR, arranged coaxially with the electro-permanent magnet MAG, is connected to the motor shaft W via a connecting element VE. In the present example, the cogging torque ring RR and the connecting element VE advantageously form a single, cover-shaped component.FIG. 8 shows a sectional view through a rotational axis D of an external rotor electric motor MOS with an axially retrofitted first retrofit unit NE1, which comprises such a device RH according to the invention. The cogging torque ring RR of the device RH can be fixedly attached to an axial outer surface AM of a rotor RO of the external rotor electric motor MOS, so that a structural main axis A of the cogging torque ring RR is aligned with the rotational axis D of the external rotor electric motor MOS. A direct connection of the cogging torque ring RR to the motor shaft W is therefore not required. The first retrofit unit NE1 further comprises a holding device HL, such as a crossbar or a bracket, which is fixed in position relative to the stator ST of the external rotor electric motor MOS and extends over the rotor RO.The holding device HL serves to mount the electro-permanent magnet MAG of the device RH, such that the main structural axis A of the electro-permanent magnet MAG is aligned with the axis of rotation D of the external rotor electric motor MOS, and so that the stator pole shoes PS of the electro-permanent magnet MAG are radially opposite the cogging torque ring RR with the rotor pole shoes PR. The electro-permanent magnet MAG can be attached to a circuit carrier LP, as shown in the example of FIG. 8, which in turn is mounted on the holding device HL. A driver module with integrated power semiconductors, or two or more power semiconductors, such as FETs, can already be applied to the circuit carrier LP for simplified current supply to the coil assembly SP of the electro-permanent magnet MAG. Furthermore, a magnetic insulator Ml is provided for magnetic decoupling between the electro-permanent magnet MAG and the axial outer surface AM of the rotor RO.

[0108] FIG 9 shows a sectional view through a rotational axis D of an internal rotor electric motor MOS with a second retrofit unit NE2 axially attached, comprising a device RH according to the invention. MG again denotes a motor housing of the internal rotor electric motor MOS. The electro-permanent magnet MAG can be fixedly attached to an axial outer surface AM of a stator ST or to the motor housing MG of the internal rotor electric motor MOS, such that a main structural axis A of the electro-permanent magnet MAG is aligned with the rotational axis D of the internal rotor electric motor MOS. The detent torque ring RR shown can be connected in a rotationally fixed manner via a connecting element VE to an axially projecting or axially extendable motor shaft WE of the internal rotor electric motor MOS, which passes axially through a through-opening OF of the electro-permanent magnet MAG.The cogging torque ring RR and the connecting element VE can again form a single component, e.g., made of magnetic steel. Furthermore, the cogging torque ring RR of the second retrofit unit NE2 is axially alignable so that it, together with the rotor pole shoes PR, is radially opposite the stator pole shoes PS of the electro-permanent magnet MAG. For magnetic decoupling, a magnetic insulator Ml is installed between the electro-permanent magnet MAG and the axial outer surface AM of the motor housing MG.

[0109] FIG 10 shows components Bu, IS, R, SP, MK, Bo of an exemplary electro-permanent magnet MAG according to an embodiment of the inventive device RH, additionally including a permanent magnet ring R and a magnetic insulator IS. In contrast to the embodiment according to FIG 1, the electrical coil or coil assembly SP, which coaxially receives the magnetic core MK, is coaxially received within a central opening OFR of the permanent magnet ring R. The coaxial arrangement of the permanent magnet ring R, the coil assembly SP, and the magnetic core MK is then itself coaxially received within a central opening OFI of a magnetic insulator IS. The latter can be, for example, a plastic ring or an aluminum ring.The magnetic insulator IS is not strictly necessary, but it serves to improve the magnetic flux guidance through the two sheet metal parts Bo, Bu of the electro-permanent magnet MAG, which then enclose the entire assembly, including the magnetic core MK, the coil assembly SP, the permanent magnet ring R, and the magnetic insulator IS, like a cage. In this illustration, the two sheet metal parts Bo, Bu are shown without the finger end pieces Eo, Eu being bent. This will be the case in the following illustration.

[0110] FIG 11 shows a sectional view through a constructive main axis A of the exemplary electro-permanent magnet MAG according to FIG 10 in an enlarged view. In this view, the coaxial arrangement of the components Bu, IS, R, SP, MK, Bo is clearly visible.

[0111] If the coil assembly SP is appropriately energized, an electromagnetic field with the corresponding sign is induced in the magnetic core MK, depending on the sign of the applied current. After the applied current ceases, an axially oriented remanent magnetic field remains in the magnetic core MK. This field is superimposed on an axially oriented permanent magnetic field of the permanent magnet ring R in the respective radially inner, central section Zo, Zu of the two sheet metal parts Bo, Bu. If both magnetic fields are additively superimposed, alternating north and south poles form at the finger ends Fo, Fu as stator pole shoes PS in the circumferential direction around the main structural axis A. Otherwise, the two magnetic fields cancel each other out, so that no north and south poles with significant magnetic field strength form at the finger ends Fo, Fu.The electromagnetic field induced by the coil arrangement SP has no effect on the permanent magnetic field emanating from the permanent magnet ring R.

[0112] FIG 12 shows the principle of a circuit arrangement SA for selectively controlling the electro-permanent magnet MAG according to the invention for potentially holding or releasing the rotor of an electric motor MO, MOS by means of a first and second current pulse that can be impressed into the coil arrangement SP of the electro-permanent magnet MAG for potentially applying a holding torque. The electro-permanent magnet MAG considered here comprises a magnetic core MK, but no permanent magnet ring R.

[0113] The electrical adjustment of the holding torque ultimately acting on the detent ring RR depends on the electrical energy of a current impressed into the coil assembly SP up to a magnetic saturation limit of the enclosed magnetic core MK. The holding torque is essentially proportional to the magnetic induction present at the stator pole shoes PS, which originates from the remanent magnetic field of the magnetic core MK when the current is switched off and is transmitted to the stator pole shoes PS via the two magnetic field conductors Bo and Bu. If the current intensity of a current impressed into the coil assembly SP by the circuit arrangement SA is constant, the electrical energy, and thus also the magnetic induction value at the stator pole shoes PS, and consequently the holding torque, can be adjusted via the pulse length of a current pulse.To reduce the holding torque, a current with the opposite sign can be impressed into the coil arrangement SP by means of the circuit arrangement SA to weaken the remanent magnetic field in the magnetic core MK. This current must exceed at least a coercive field strength Kc characteristic of the magnetic material used. The holding torque can be adjusted in a range from 0% to 100%, where 100% refers to a maximum induction value of the remanent magnetic field. Setting a predetermined value for the cogging torque, which corresponds to a predetermined torque value for the holding torque, can be done, for example, as a setpoint value that the control unit MC of the circuit arrangement SA receives, for example, via an interface of an electric motor, a retrofit unit, or an arrangement according to the invention.

[0114] The circuit arrangement SA comprises a series connection of a coil SP1 of the electro-permanent magnet MAG, a capacitor C, and a changeover switch WS. The changeover switch WS can also be implemented, for example, by two single-pole switching elements S1 and S2 that can be controlled together. When the changeover switch WS is in a holding position (marked "on"), the capacitor C is charged via a supply voltage potential V+ applied through the switching contact for the holding position and via the series-connected coil SP1 until the capacitor C is saturated. This results in a brief current pulse through the coil SP1, the duration of which is determined by the time constant derived from the inductance of the coil SP1 and the capacitance of the capacitor C. Thus, a current pulse flows through the coil SP1, initially increasing and then decreasing, generating a corresponding magnetic field.The pulse length of the current pulse is typically in the range of 5 ms to 200 ms. RV denotes an optional series resistor used to limit current spikes occurring during switching operations.

[0115] When the changeover switch WS is switched from the holding position to a freewheeling position (marked "off"), the capacitor C discharges via the coil SP1 with reverse current direction and forms a corresponding magnetic field with reverse magnetic sign.

[0116] The inductance value of the electrical coil and the capacitance value of the capacitor C are dimensioned such that when the second end of the series circuit is connected to the common reference potential M, a short-term decaying sinusoidal current pulse oscillation occurs to demagnetize the magnetic core MK of the electro-permanent magnet MAG.

[0117] The circuit arrangement SA shown further comprises a control unit MC and a changeover switch WS, which can be controlled via the control unit MC, to impress the first or second short-duration current pulse into the coil arrangement SP of the electro-permanent magnet MAG. The control unit MC is, in particular, a processor-based control unit and preferably a microcontroller. The changeover switch WS can, for example, be a relay. Alternatively, it can be implemented by two individual switching elements. The switching elements are, in particular, switching transistors, preferably so-called FETs.

[0118] Such a circuit arrangement advantageously requires only a few components. Additionally, the electrical energy stored in capacitor C ensures that even in the event of a power failure, sufficient demagnetization of the magnetic core MK is possible to release the magnetic cogging torque during freewheeling operation. This allows the actuator, driven by the return spring, to reliably return to its safe rest position. A further significant advantage is that, once capacitor C has been charged, the actuator circuit arrangement requires no significant electrical power during holding operation.

[0119] In particular, the inductance of the electrical coil SP1 and the capacitance of the capacitor C are dimensioned such that when the second end of the series circuit is connected to the common reference potential M, a brief, decaying sinusoidal current pulse oscillation is generated to demagnetize the magnetic core MK of the electro-permanent magnet MAG. This decaying sinusoidal current pulse oscillation can, for example, have 5 to 20 oscillation amplitudes. This advantageously allows for almost complete demagnetization of the magnetic core.

[0120] FIG 13 shows the principle of a second circuit order SA with a coil arrangement SP comprising two electrical coils SP1 and SP2 and a magnetic field sensor MF. The two coils SP1 and SP2 are connected to a common, here positive, supply voltage V+ as part of the coil arrangement SP. Both coils SP1 and SP2 are each connected to a common reference potential (ground) via a switching element S1 and S2, preferably via a switching transistor. The control of the two switching elements S1 and S2 is effected by a control unit MC of the actuator.

[0121] To engage a holding mode (indicated by "on") of the actuator, in which the rotor RO of the electric motor MO, MOS magnetically engages with the detent ring RR of the electro-permanent magnet MAG, the first switching element S1 is briefly closed, causing a short current pulse to be impressed in the coil SP1 to generate a magnetic field in the magnetic core MK of the electro-permanent magnet MAG. After the first switching element S1 reopens, a magnetic remanent field remains in the magnetic core MK to provide a magnetic detent torque on the outside of the rotor RO.

[0122] To engage freewheeling mode (indicated by "off"), the second switching element S2 is briefly closed, causing a short current pulse to be impressed in coil SP2. This generates a magnetic field in the core MK of the electro-permanent magnet that opposes the remanent magnetic field. After the second switching element S2 reopens, the previous magnetic remanent field in the core MK is essentially dissipated. With the removal of the remanent magnetic field, the magnetic cogging torque between the rotor RO of the electric motor MO, MOS and the cogging torque ring RR of the electro-permanent magnet MAG is eliminated, and the rotor RO can now move freely. In the case of a fail-safe actuator, the actuator, driven by a pre-tensioned return spring, can now be moved to its safe rest position via the reduction gear.

[0123] The left part of FIG. 13 shows a magnetic field sensor MG arranged in the region of one of the two poles PE of the magnetic core MK of the electro-permanent magnet MAG. The latter is connected to a control unit MC of the actuator to detect a current magnetic induction value. The control unit MC is configured to control the first switching element S1 of the circuit arrangement SA to induce the first current pulse with a first predetermined pulse length, to detect a current magnetic induction value after its termination, and, if the detected magnetic induction value does not exceed a predetermined upper limit, to repeatedly induce the first current pulse with increasingly longer first pulse lengths until, after its termination, a current magnetic induction value exceeds the predetermined upper limit.

[0124] In the present example, the control unit MC is additionally configured to control the second switching element S2 to imprint the second current pulse with a second predetermined pulse length, to detect a current magnetic induction value after its termination, and, in the event that the detected magnetic induction value does not fall below a predetermined lower limit, to repeatedly imprint the second current pulse with an increasingly longer second pulse length until, after its termination, a current induction value falls below the predetermined lower limit.

[0125] As can be seen in the left part of FIG. 13, a voltage sensing unit VM is connected in parallel to one of the two coils, here the first coil SP1. The voltage sensing unit VM is connected to the control unit MC to detect a voltage signal. The latter is configured to analyze the voltage signal for the presence of repetitive voltage pulses and output these as rotational pulses to a motor control unit of the actuator to control the electric motor MO, MOS. The voltage signal can be detected, for example, via an analog-to-digital converter (ADC). The ADC can already be integrated into the control unit MC or the microcontroller. The analysis of the voltage signal for the presence of repetitive voltage pulses can be performed, for example, using a phased-locked loop (PLL) circuit or a software-implemented PLL function executed by the control unit MC.FIG 14 shows the principle of a third circuit order SA with a coil arrangement SP in a full bridge, a magnetic field sensor MF, and a voltage sensing unit VM for providing rotational pulses. In this example, the coil of the coil arrangement SP is connected in the full bridge such that when the first and fourth switching elements S1, S4 are closed, a first short-term current pulse is impressed into the coil, and when the second and third switching elements S2, S3 are closed, an opposing second short-term current pulse is impressed into the coil of the electro-permanent magnet S1. The four switching elements S1-S4 are connected to a control unit MC of the actuator for control purposes. The detection of the rotational pulses is implemented analogously to the embodiment shown in FIG 13.

[0126] In summary, the invention relates to a device RH for providing an electrically adjustable, non-contact magnetic cogging torque between an electro-permanent magnet MAG and a cogging torque ring RR rotatable about a rotational axis D with distributed rotor pole shoes PR. The electro-permanent magnet MAG comprises a magnetic core MK, a coil arrangement SP surrounding it, and a magnetic field conductor Bo, Bu connected to each of its pole ends PE. To provide the cogging torque, a suitable current pulse can be impressed into the coil arrangement SP. Both magnetic field conductors extend from the pole ends to the rotor pole shoes and form stator pole shoes at their respective ends, which are opposite the cogging torque ring with the rotor pole shoes. According to the invention, the magnetic field conductors Bo, Bu each form a plurality of finger-shaped sections Fo, Fu, each with a finger end piece Eo, Eu.The finger end pieces Eo, Eu are designed and aligned in a radial outer area RA of the electro-permanent magnet MAG such that the finger end pieces Eo, Eu of one of the two magnetic field conductors Bo, Bu engage between the finger end pieces Eu, Eo of the other magnetic field conductor Bu, Bo in order to form stator pole shoes PS with circumferentially alternating north and south poles N, S.

[0127] Reference symbol list

[0128] A constructive main axis, axis of symmetry

[0129] AA axial outer side of the electro-permanent magnet

[0130] AD outer diameter of the device

[0131] AM axial outer side of the electric motor

[0132] Ao, Au Finger base of the magnetic field conductor, sheet metal part

[0133] AS axial outer side of the motor

[0134] Bo, Bu magnetic field conductor, sheet metal part

[0135] C capacitor, electrolytic capacitor

[0136] D axis of rotation

[0137] DM Motor diameter

[0138] EA electrical connections

[0139] Eo, Eu fingertip

[0140] Fo, Fu finger-shaped section, finger section of the magnetic field conductor

[0141] G gearbox, reduction gearbox

[0142] GP Base Plate

[0143] H Height of the electric motor, height of the rotor

[0144] HE component height of the facility

[0145] IS magnetic insulator

[0146] L supply line

[0147] LP circuit carrier, printed circuit board

[0148] LS air gap

[0149] M mass, reference potential

[0150] MAG Electro-permanent magnet, remanent magnet

[0151] MC control unit, microcontroller

[0152] MD Diameter of the electro-permanent magnet

[0153] MF magnetic field sensor

[0154] MG engine casing

[0155] Ml magnetic insulator

[0156] MK magnetic core, magnetic coil core

[0157] MO electric motor, motor with integrated switchable cogging torque limiter

[0158] MOS electric motor, motor

[0159] MZ engine gear, engine pinion

[0160] North Pole, Magnetic Pole

[0161] NE Retrofit kit

[0162] NU recess, Nut OF through-hole, opening of the electro-permanent magnet

[0163] OFI through-hole of the magnetic insulator

[0164] OFR through-hole of the permanent magnet ring

[0165] OFS coil through-hole

[0166] PB component, passive component

[0167] PE Polende

[0168] PM permanent magnets, permanent magnetic poles

[0169] PR Rotor Pole Shoes

[0170] PS Stator pole shoes

[0171] R Permanent magnet ring

[0172] RA radial outer surface of the electro-permanent magnet

[0173] RAB radial outer area of ​​the electro-permanent magnet

[0174] RH device for cogging torque inhibition

[0175] RO rotor, rotor bell, rotor cup

[0176] ROA radial outer surface of the rotor

[0177] RR Detent ring

[0178] RV series resistor

[0179] South Pole, magnetic pole

[0180] SA circuit arrangement

[0181] S1 - S4 switching elements, transistors

[0182] SP coil arrangement

[0183] SP1. SP2 coil

[0184] ST Stator

[0185] TR control unit for motor and cogging torque damping

[0186] US underside of the detent ring

[0187] VE connecting element, struts, disc

[0188] VM pulse detection unit, voltage detection unit

[0189] V+ Supply voltage

[0190] W shaft, motor shaft, rotor shaft

[0191] WS changeover switch, switching element

[0192] Where, Wu angled end piece of the magnetic field conductor

[0193] Zo, radially inner, central section

[0194] ZR gear

Claims

Patent claims 1. Device (RH) for providing an electrically adjustable, non-contact magnetic cogging torque between an electro-permanent magnet (MAG) and a cogging torque ring (RR) arranged coaxially thereto and rotatable about an axis of rotation (D), wherein the cogging torque ring (RR) has a number npR of rotor pole shoes (RP) arranged preferably uniformly in the circumferential direction to the axis of rotation (D), wherein the electro-permanent magnet (MAG) comprises a magnetic core (MK) for forming a north and south pole at two pole ends (PE) of the magnetic core (MK), at least one electrical coil (SP) enclosing the magnetic core (MK) and a magnetic field conductor (Bo, Bu) each magnetically connected to the pole ends (PE) of the magnetic core (MK),wherein, to provide the electrically adjustable magnetic cogging torque, a current pulse with suitable current strength and / or pulse length and with suitable current direction can be impressed into the at least one electrical coil (SP), wherein both magnetic field conductors (Bo, Bu) extend from the pole ends (PE) of the magnetic core (MK) in the direction towards the rotor pole shoes (PR) of the cogging torque ring (RR) and form stator pole shoes (PS) at the respective ends of the two magnetic field conductors (Bo, Bu), wherein both magnetic field conductors (Bo, Bu) are rotationally fixed to one another, and wherein the stator pole shoes (PS) are arranged opposite the cogging torque ring (RR) with the rotor pole shoes (RP) to provide the cogging torque, characterized in that the two magnetic field conductors (Bo, Bu) each form a plurality np of finger-shaped sections (Fo, Fu) each with a finger end piece (Eo, Eu), wherein the finger end pieces (Eo,Eu) in a radial outer region (RA) of the electro-permanent magnet (MAG) are designed and aligned such that the finger ends (Eo, Eu) of one of the two magnetic field conductors (Bo, Bu) engage between the finger ends (Eu, Eo) of the other magnetic field conductor (Bu, Bo) to form a number of nps of stator pole shoes (PS) with north and south poles (N,S) alternating circumferentially to the axis of rotation (D).

2. Device (RH) according to claim 1 , - wherein the electro-permanent magnet (MAG) comprises, in relation to its main structural axis (A), a straight prismatic or straight hollow prismatic, in particular a cylindrical or hollow cylindrical magnetic core (MK), comprising at least one electrical coil (SP, SP2) coaxially surrounding the magnetic core (MK) and two preferably identical magnetically conductive sheet metal parts (Bo, Bu) as magnetic field conductors, - wherein the two sheet metal parts (Bo, Bu) enclose the magnetic core (MK) with the at least one electrical coil (SP) axially opposite each other in relation to the main structural axis (A) and are magnetically connected to one of the pole ends (PE) of the magnetic core (MK) by a radially inner central sheet metal section (Zo, Zu), - wherein the two sheet metal parts (Bo, Bu) form the majority np of the finger sections (Fo, Fu) extending radially outwards from there, and - wherein the two sheet metal parts (Bo, Bu) are arranged in the circumferential direction to the main constructive axis (A) rotated relative to each other such that the finger end pieces (Eo, Eu) of one of the sheet metal parts (Bo, Bu) engage between the finger end pieces (Eu, Eo) of the other sheet metal part (Bu, Bo), wherein the axis of rotation (D) of the device (RH) and the main axis (A) of the electro-permanent magnet (MAG) are aligned with each other.

3. Device (RH) according to claim 2, wherein the finger end pieces (Eo, Eu) of the two sheet metal parts (Bo, Bu) are bent towards each other in an axial direction to the main axis (A) of the electro-permanent magnet (MAG) in order to form the circumferentially distributed stator pole shoes (PS) on the radial outer side (RA) of the radial outer area (RAB), wherein the stator pole shoes (PS) are arranged radially opposite the cogging torque ring (RR) with the rotor pole shoes (PR).

4. Device (RH) according to claim 2, - wherein the finger-shaped sections (Fo, Fu) of one of the two sheet metal parts (Bo, Bu) together with their finger end pieces (Eo, Eu) extend in a radial direction towards the radial outer surface (AR) and wherein the finger-shaped sections (Fo, Fu) together with their finger end pieces (Eo, Eu) lie in a common plane, and - wherein the finger-shaped sections (Fu, Fo) of the other sheet metal part (Bu, Bo) each have a central finger piece (Wu, Wo) bent in the axial direction to the main axis (A) of the electro-permanent magnet (MAG), wherein the respective adjacent finger end pieces (Eu, Eo) are bent in the radial direction to the main axis (A) of the electro-permanent magnet (MAG) in order to form the circumferentially distributed stator pole shoes (PS) in a common plane with the finger end pieces (Eo, Eu) of the first sheet metal part (Bo, Bu), wherein the stator pole shoes (PS) are arranged axially opposite the cogging torque ring (RR) with the rotor pole shoes (PR).

5. Device (RH) according to one of claims 2 to 4, wherein the electro-permanent magnet (MAG) comprises a straight hollow prismatic, in particular a hollow cylindrical permanent magnet ring (R), wherein the permanent magnet ring (R) coaxially surrounds the at least one electrical coil (SP1, SP2) and wherein the permanent magnet ring (R) is made of a magnetic material with a remanent flux density BR of at least 0.5 T, in particular of at least 0.7 T, and with a coercive field strength Kc of more than 100 kA / m, in particular of at least 500 kA / m.

6. Device (RH) according to one of the preceding claims, wherein the magnetic core (MK) of the electro-permanent magnet (MAG) is made of a magnetic material with a remanent flux density BR of at least 1 T, in particular of at least 1.2 T, and with a coercive field strength Kc in the range of 25 kA / m to 100 kA / m, in particular in a range of 40 kA / m to 100 kA / m, and / or with a magnetic energy density BH ma x of at least 30 kJ / m 3 is manufactured.

7. Device (RH) according to one of the preceding claims, wherein the two magnetic field conductors (Bo, Bu) are made of a magnetic material with a permeability p r of at least 40, in particular of at least 300, and in particular made of electrical steel.

8. Electric motor (MO), comprising a stator (ST), a rotor (RO) rotatably arranged about an axis of rotation (D) of the electric motor (MO), and a device (RH) according to one of the preceding claims for providing the electrically adjustable, non-contact magnetic cogging torque between an electro-permanent magnet (MAG) and a cogging torque ring (RR) rotatably arranged about the axis of rotation (D) of the electric motor (MO), wherein the cogging torque ring (RR) is rotationally fixed to the rotor (RO) of the electric motor (MO) or forms such a cogging torque ring (RR), wherein a structural main axis (A) of the cogging torque ring (RR) and of the electro-permanent magnet (MAG) is aligned with the axis of rotation (D) of the electric motor (MO), wherein the cogging torque ring (RR) is arranged axially outside the stator (ST), and wherein the electro-permanent magnet (MAG) is axially adjacent to the stator (ST) of the electric motor (MO).and wherein the cogging torque ring (RR) and the electro-permanent magnet (MAG) are axially aligned to each other such that the cogging torque ring (RR) with the rotor pole shoes (PR) is opposite the stator pole shoes (PS) of the electro-permanent magnet (MAG).

9. First retrofit unit (NE1) comprising a device (RH) according to any one of claims 1 to 7 for retrofitting an electrically adjustable and non-contact magnetic cogging torque lock to an external rotor electric motor (MOS), wherein the cogging torque ring (RR) of the device (RH) can be rotatably mounted on an axial outer side (AM) of a rotor (RO) of the external rotor electric motor (MOS) such that a structural main axis (A) of the cogging torque ring (RR) is aligned with the axis of rotation (D) of the external rotor electric motor (MOS), wherein the first retrofit unit (NE1) has a holding device (HL) that is fixed in position relative to the stator (ST) of the external rotor electric motor (MOS) and extends over the rotor (RO), and wherein the electro-permanent magnet (MAG) of the device (RH) is attached to the holding device (HL).so that the constructive main axis (A) of the electro-permanent magnet (MAG) is aligned with the axis of rotation (D) of the external rotor electric motor (MOS) and so that the stator pole shoes (PS) of the electro-permanent magnet (MAG) are aligned with the cogging torque ring (RR) with the rotor pole shoes, (PR) radially opposite each other.

10. Second retrofit unit (NE2) comprising a device (RH) according to one of claims 1 to 7 for retrofitting an electrically adjustable and contactless magnetic cogging torque lock to an internal rotor electric motor (MOS), wherein the electro-permanent magnet (MAG) of the device (RH) can be fixedly attached to an axial outer side (AM) of a stator (ST) or motor housing (MG) of the internal rotor electric motor (MOS), such that a structural main axis (A) of the electro-permanent magnet (MAG) is aligned with the axis of rotation (D) of the internal rotor electric motor (MOS), wherein the cogging torque ring (RR) of the second retrofit unit (NE2) can be connected via a connecting element (VE) in a rotationally fixed manner to an axially projecting or axially extendable motor shaft (WE) of the internal rotor electric motor (MOS) which passes axially through a through-opening (OF) of the electro-permanent magnet (MAG),and wherein the cogging torque ring (RR) of the second retrofit unit (NE2) is axially alignable, so that the cogging torque ring (RR) with the rotor pole shoes (PR) aligns with the stator pole shoes, (PS) of the electro-permanent magnet (MAG) is radially opposite.

11. Arrangement comprising an electric motor (MO) according to claim 8, an external rotor electric motor (MOS) with a first retrofit unit (NE1) attached thereto according to claim 9, or an internal rotor electric motor (MOS) with a second retrofit unit (NE2) attached thereto according to claim 10, and each comprising a circuit arrangement (SA) with a control unit (MC) and with at least two switching elements (S1-S4) controllable by means of the control unit (MC), wherein a first switching element (S1-S4) is used to hold the detent torque ring (RR) in a holding mode by means of the control unit (MC). A current pulse can be impressed into the at least one electrical coil (SP, SP2) of the electro-permanent magnet (MAG) via the at least two switching elements (S1-S4), so that a remanent magnetic field still present in the electro-permanent magnet (MAG) acting on the stator pole shoes (PS) of the electro-permanent magnet (MAG) subsequently remains to provide the magnetic cogging torque, and wherein a second current pulse can be impressed into the at least one electrical coil (SP, SP2) via the at least two switching elements (S1-S4) of the circuit arrangement (SA) to release the cogging torque ring (RR) in a freewheeling operation, so that the remanent magnetic field still present in the electro-permanent magnet (MAG) acting on the stator pole shoes (PS) to release the magnetic cogging torque is essentially dissipated.

12. Arrangement according to claim 11, wherein the electro-permanent magnet (MAG) has two electrical coils (SP, SP2), wherein a voltage detection unit (VM) connected to the control unit (MC) is connected in parallel to one of these electrical coils (SP, SP2) for detecting a voltage signal, wherein the control unit (MC) is configured to analyze the voltage signal for the presence of repetitive voltage pulses and to output these as rotational pulses.

13. Arrangement according to claim 11 or 12, - wherein the arrangement comprises a magnetic field sensor (MF), in particular a Hall sensor, arranged in the area of ​​the stator pole shoes (PS) of the electro-permanent magnet (MAG) for detecting a magnetic induction value, - wherein the control unit (MC) is configured to control the at least two switching elements (S1-S4) of the circuit arrangement (SA) to induce the first current pulse with a first predetermined pulse length, to detect a current magnetic induction value after its termination, and, in the event that the detected magnetic induction value does not exceed a predetermined upper limit, to repeatedly induce the first current pulse with an increasingly longer first pulse length until, after its termination, a current magnetic induction value exceeds the predetermined upper limit, and / or - wherein the control unit (MC) is configured to control the at least two switching elements (S1-S4) of the circuit arrangement (SA) to induce the second current pulse with a second predetermined pulse length, to detect a current magnetic induction value after its completion, and, in the event that the detected magnetic induction value does not fall below a predetermined lower limit, to repeat the second current pulse with an increasingly longer second pulse length to imprint until, after its completion, the current magnetic induction value falls below the specified lower limit.

14. First actuator comprising an arrangement according to one of claims 11 to 13, in particular a reduction gear downstream of the electric motor (MO, MOS), and an output-side actuating element with an actuating connection, - wherein the control unit (MC) is configured to receive a control signal and to control the electric motor (MO, MOS) accordingly to move the actuator from a predetermined first position to a predetermined second position and vice versa, - wherein the control unit (MC) is configured to control the at least two switching elements (S1-S4) for controlling the electro-permanent magnet (MAG) in such a way that the actuator for moving the actuating element from the first actuating position to the second actuating position switches from a holding mode to a freewheeling mode when the electric motor (MO, MOS) is actuated, in particular shortly before or after actuating the electric motor (MO, MOS), and - wherein the control unit (MC) is configured to control the at least two switching elements (S1-S4) in such a way that the actuator switches from freewheeling operation to holding operation upon reaching the second positioning position, in particular shortly before or after reaching the second positioning position.

15. Second actuator comprising an arrangement according to one of claims 11 to 13, in particular a reduction gear downstream of the electric motor (MO, MOS), and an output-side actuating element with an actuating connection, - wherein the actuator has a return spring to provide a return torque acting on the actuating element for automatically moving the actuating element into a safe rest position, in particular in the event of a power failure for the actuator or upon receiving a switch-off signal to move the actuating element into a safe rest position, wherein the return torque causes a rotor return torque on the electric motor (MO, MOS), - wherein the control unit (MC) is configured to control the electric motor (MO, MOS) to move the actuator from the safe rest position to an actuating position when the power supply is switched on or when a switch-on signal is received, and wherein the control unit is configured to control the at least two switching elements (S1-S4) in such a way that the actuator switches from a freewheeling operation to a holding operation when the actuating position is reached, in particular shortly before or after reaching the actuating position, - wherein the holding torque applied to the rotor (RO) of the electric motor (MO, MOS) by means of the electro-permanent magnet (MAG) during holding operation is greater than the rotor restoring torque acting on the rotor (RO) of the electric motor (MO, MOS), and - wherein the control unit (MC) is configured to control the at least two switching elements (S1-S4) of the circuit arrangement (SA) upon receipt of a switch-off signal or upon failure of the power supply, such that the actuator switches from holding mode to free-running mode, whereby the actuating element subsequently returns automatically from the actuating position to the safe rest position.

Images