Rotary actuator

Abstract

The invention relates to a rotary actuator (1), comprising: - a stator (10), - at least one stator coil (11) which is connected to the stator (10) in such a way that a force acting on the stator coil (11) is transmitted to the stator (10); - an armature (20) which is rotatable about an axis of rotation (2) relative to the stator (10), - at least one armature coil (21) which is connected to the armature (20) in such a way that a force acting on the armature coil (21) is transmitted to the armature (20); - power lines (3) which can be used to energize the at least one stator coil (11), - cables (4) which can be used to energize the at least one armature coil (21), - a rotational angle limiting device (5) which is used to limit a rotation of the armature relative to the stator to a rotational angle range of from 0 to 359 degrees.

Description

[0001] Description

[0002] rotary actuator

[0003] The present invention relates to a rotary actuator, a method for operating the rotary actuator and various uses of the rotary actuator.

[0004] Switching devices for low-voltage and high-voltage applications such as load switches, disconnectors or circuit breakers can, due to their design, have two mechanical disadvantages: Firstly, when the switching device is switched on, i.e. when the contact system closes, the mass of the moving contact and also the mass of the switch kinematics are abruptly stopped at the galvanic contact point, which can lead to contact bounce. Secondly, the two contacts can easily weld together due to arcing. Therefore, when the switching device is switched off, i.e. when the contact system is opened, a so-called separating blow, i.e. a greater force for contact separation, must be generated to loosen or break up any welding in the contact system.Conventional drives for switchgear, which convert the rotary motion of a drive shaft into a linear motion of the moving contact, deliver a more continuous force precisely in this range. These drives for switchgear include, for example, spring drives and magnetic drives (classic solenoid actuators).

[0005] To date, attempts have been made to improve the bounce behavior using special kinematics, e.g. bell cranks to control the speed profile, or to brake the moving contact shortly before galvanic contact using servo motors including a complex control system. The separating impact, on the other hand, has so far been achieved with additional accelerated masses, which in turn require a higher overall drive energy. Main drives for circuit breakers with vacuum tubes sometimes use linear or rotary drives based on lifting magnets. These generally have relatively small forces or torques at the start of the movement due to a large air gap, which leads to low efficiency. This means that a disproportionately large amount of electrical energy has to be used at the start of the movement to start the movement. To date, the initial force has been increased by special geometries of the air gap.However, this requires a relatively complicated geometry of the armature and / or stator and reduces the force in the remaining stroke range.

[0006] Switchgear often features a short-circuiter to extinguish an arc fault before it causes major damage from a metallic short circuit. The short-circuiter must operate within a few milliseconds. Explosives are usually used as the driving force, but this results in contamination of the system and the release of toxic substances. Alternatively, short-circuiters driven by stored spring energy are used, sometimes requiring considerable mechanical effort.

[0007] There is therefore a need for an improved drive that can be used in switching devices, e.g. circuit breakers, and short-circuiters.

[0008] This object is achieved according to the invention by a rotary actuator having the features specified in claim 1, a method having the features specified in claim 9, a switching device having the features specified in claim 13, a switching device having the features specified in claim 14 and a short-circuiter having the features specified in claim 15.

[0009] The rotary actuator according to the invention has a stator. The stator has at least one stator coil which is connected to the stator in such a way that a force acting on the stator coil is transmitted to the stator. The rotary actuator has an armature. The armature is rotatable about an axis of rotation relative to the stator. The armature has at least one armature coil which is connected to the armature in such a way that a force acting on the armature coil is transmitted to the armature. The rotary actuator has electrical lines through which the at least one stator coil can be energized. The rotary actuator has electrical lines through which the at least one armature coil can be energized.

[0010] The object is further achieved according to the invention by a method for operating the aforementioned rotary actuator, wherein a current pulse causes a braking or acceleration pulse. The triggering of the current pulse is triggered by an angular position of the armature relative to the stator.

[0011] The object is further achieved according to the invention by a switching device with at least one switch, wherein a rotary actuator according to the invention acts as an additional drive for the switch. The switching device has a rotary shaft and a main drive acting on the rotary shaft. Movement of a moving contact of the at least one switch is brought about by rotation of the rotary shaft. The switching device also has a rotary actuator, as described above, the rotary actuator acting as an additional drive for the switch. The armature of the rotary actuator is arranged non-rotatably on and coaxial with the rotary shaft. If the rotary actuator is correctly designed, the moving contact can be briefly braked or accelerated shortly before it touches the fixed contact when the switch is switched on, in order to improve the bounce behavior of the switching device. When the switch is switched off, an additional acceleration pulse can be delivered which acts as a separating shock.Such a preferably relatively small rotary actuator as an additional drive can be attached to practically any switch that has a rotary shaft. In particular, the bounce and switching off behavior of medium-voltage circuit breakers with a high switching capacity and thus usually large masses of the moving contacts can be influenced in this way. It can be particularly advantageous if the rotary actuator is coupled directly to the moving contact and not via intermediate springs. If a servo motor serves as the main drive of the switch, no complex control of the servo motors is necessary; only a precise reference signal for the galvanic contact is required to trigger the current pulse for the rotary actuator. Such reference contacts are common, for example, in high-voltage switches that are switched synchronously with the mains (Hall sensor).The rotary actuator generates a very strong torque pulse that is available almost instantaneously. This contrasts with relatively slow magnetic drives, where a soft-iron magnetic circuit must first be magnetized to generate the force or torque.

[0012] The object is further achieved according to the invention by a switching device having at least one switch, wherein a rotary actuator according to the invention acts as a main drive of the switching device. The switching device has a rotary actuator as described above, wherein the rotary actuator acts as a main drive of the switch and wherein a movement of a moving contact of the at least one switch is caused by a rotation of the rotary actuator. Such a rotary actuator can be used by suitable timing to drive the entire switch or the entire switching device.

[0013] The rotary drive according to the invention can be used as a main drive for a switching device, since the current pulses can be repeated at short intervals in a suitably timed manner in order to generate several, even relatively strong torque pulses. The relatively fast switching sequences required for this can be implemented by a suitable design of an electrical energy storage device, e.g. a capacitor, and a charging technology for the electrical energy storage device. The pulse spacing and the pulse length of the current pulses can be matched to the required torque. The decisive factor is the relatively rapid current rise which produces the torque. The coil current can therefore be switched off shortly after the maximum coil current is reached by suitable power electronics in order to save energy, which preferably comes from a capacitor bank, i.e. several capacitors connected together.This allows pulses to be generated at intervals of a few milliseconds, as needed to drive the switching device. The pole pitch, i.e., the number of partial coils in the armature or stator, can be adjusted as needed to adapt the torque to the requirements, together with the electronic timing of the current supply.

[0014] The object is also achieved according to the invention by a short-circuiter. The short-circuiter has a rotary actuator, as described above. A movement of a closing contact of the short-circuiter is brought about by the rotary actuator. The rotary drive according to the invention can be used in a short-circuiter where, for example, blade contacts, similar to a circuit breaker, are closed relatively quickly to create a metallic short circuit. An electrical energy store, for example a capacitor, is discharged into the coil system, thereby triggering a relatively rapid rotary movement of a closing contact. The drive by the rotary actuator can be used repeatedly, in contrast to short-circuiters driven by explosives.

[0015] An alternative application for the rotary actuator is an impact wrench for loosening wheel bolts on a motor vehicle. This is possible because the rotary actuator can generate a force pulse per current pulse through the coils, thus creating a repetitive torque (separating impact) for loosening stuck bolts.

[0016] The invention is based on a rotary actuator with a limited angle of rotation. The principle of the invention is a precisely timed surge current through two or more coils, which preferably partially overlap. A first coil is wound in the stator which is firmly connected to the switch housing, and a second coil is wound on the armature. After suitable triggering, e.g. by a Hall sensor for generating a trigger signal, or by determining a trigger time from typical points on the current curve of a main magnetic drive, if present, an electrical energy storage device such as a capacitor can be discharged in a surge-like manner via the coils connected in series or parallel. This surge current leads to a torque pulse which is almost instantaneous, and the sign of the torque pulse can be defined by the current direction, e.g. in the armature coil.

[0017] A Lorentz force acts between the energized coils, and a reluctance force acts throughout the entire armature-stator arrangement. The resulting force is relatively dynamic and effective over a relatively long stroke: relatively high pulse torques can be achieved per current pulse. The generated force is immediately available in full at the initial position of the armature. Furthermore, the rotary actuator is easily scalable.

[0018] The pulse spacing and the pulse length of the current pulses can be adjusted to the required torque. The speed of the temporal rise of the current that causes the torque is crucial for the level of torque. The coil current can therefore be switched off shortly after the maximum coil current is reached by suitable power electronics in order to save energy, which preferably comes from a capacitor bank, i.e. several capacitors connected together. In this way, pulses can be generated at intervals of a few milliseconds if necessary to drive the circuit breaker. The pole pitch, i.e. the number of partial coils in the armature or stator, can be adjusted as required in order to adapt the torque to requirements together with the electronic timing of the current supply to the coils. Advantageous embodiments and further developments of the invention are specified in the dependent claims.

[0019] According to the invention, the stator and armature rotate only over a defined, limited angular range. Since the armature does not rotate continuously in one direction, as in an electric motor, but only performs back-and-forth rotations over a limited angular range, no sliding contacts are required to supply current to the at least one armature coil, but only flexible cable connections between the at least one armature coil and a voltage source.

[0020] According to a preferred embodiment of the invention, the rotation of the armature relative to the stator is limited to an angle of rotation range of 0 to 90 degrees, more preferably 0 to 60 degrees. An advantage of this is that the power supply to the armature is simplified and can be implemented using flexible cables, without the need for sliding contacts.

[0021] According to a preferred embodiment of the invention, the armature and the stator are each made at least partially of soft magnetic material. One advantage of this is that the reluctance force in the metallic armature and stator is also utilized.

[0022] According to a preferred embodiment of the invention, the armature and the stator are each laminated. The laminate planes extend transversely to the longitudinal axes of the armature and stator. One advantage is that the lamination reduces eddy currents in the longitudinal direction.

[0023] According to a preferred embodiment of the invention, the armature and the stator each have the shape of a hollow cylinder. The armature is arranged coaxially to the stator inside the stator. One advantage here is the compact design. According to a preferred embodiment of the invention, the armature has grooves on its outer circumference into which the at least one armature coil is inserted. Depending on the design, the grooves can be closed with wedges towards the surface in order to prevent the armature winding from being released due to centrifugal forces. One advantage here is the compact design.

[0024] According to a preferred embodiment of the invention, the stator has grooves on its inner circumference, into which the at least one stator coil is inserted. Depending on the design, the grooves can be closed with wedges towards the surface to prevent the stator winding from being released by centrifugal forces. One advantage of this is the compact design. Since the centrifugal forces act outwards and press the stator coils into the grooves, grooves on the inner circumference of the stator generally do not need to be closed.

[0025] According to a preferred embodiment of the invention, the at least one stator coil and the at least one armature coil are connected in series. One advantage of this is that a surge current through the series-connected coils results in a virtually instantaneous torque pulse, whereby the sign of the torque pulse can be defined by the current direction, e.g., in the armature coil.

[0026] According to a preferred embodiment of the invention, the number of pole pairs of the armature and the stator is the same. For example, the armature has three phases, each with an armature coil; the coils generate magnetic fields whose axes are directed in the directions 0 °, 120 ° and 240 °. The stator is designed in a similar way. Depending on the requirements, the number of pole pairs can be such that the armature and stator each have a pitch of 3, a pitch of 4 or a pitch of 5. Depending on the requirements, the armature and stator can also have any other feasible pitch. One advantage of this is that the choice of pitch allows the rotary actuator to be adapted to different requirements.

[0027] According to a preferred embodiment of the invention, the rotary actuator has an electrical energy storage device, e.g. a capacitor, which can discharge its charge into the at least one stator coil and / or at least one armature coil. An electrical energy storage device can be discharged in a burst-like manner via the coils connected in series or in parallel. One advantage of this is that such a burst current leads to a torque pulse with almost no delay, wherein the sign of the torque pulse can be defined by the current direction, e.g. in the armature coil.

[0028] According to a preferred embodiment of the invention, the rotary actuator has a control unit which controls the current supply to the at least one stator coil and the at least one armature coil. After suitable triggering, e.g. by a Hall sensor for generating a trigger signal at the galvanic contact point of a vacuum tube or by determining a trigger time from typical points on the current curve of a possibly present main magnetic drive of a switching device, an electrical energy store, e.g. a capacitor, can be discharged in a burst manner via the coils connected in series or in parallel. After receiving a trigger signal, the control unit can cause an electrical energy store, such as a capacitor, to discharge its electrical charge into the at least one stator coil and the at least one armature coil.One advantage is that the control unit allows the movements of the rotary actuator to be adapted to different requirements.

[0029] According to a preferred embodiment of the invention, the control unit is configured to control electronic reversal of the coils. The coils are thus not reversed using sliding contacts, but electronically. One advantage is that this electronic reversal process is simpler and causes less wear than an electromechanical reversal process.

[0030] According to a preferred embodiment of the invention, the at least one stator coil and the at least one armature coil overlap radially. The achievable torque depends on the degree of overlap. One advantage is that the rotary actuator can be adapted to different requirements by selecting the degree of coil overlap.

[0031] According to a preferred embodiment of the invention, a current pulse, triggered by the angular position of the armature relative to the stator, produces a braking or acceleration pulse. One advantage of this is that the current pulse allows the movements of the rotary actuator to be adapted to different requirements.

[0032] According to a preferred embodiment of the invention, several consecutive current pulses cause a continuous movement of the armature, e.g., over an angular range of more than 15 degrees. One advantage of this is that the current pulses allow the movements of the rotary actuator to be adapted to different requirements.

[0033] According to a preferred embodiment of the invention, the one or more current pulses exhibit a current change dl / dt. One advantage of this is that the magnitude of the current change allows the movements of the rotary actuator to be adapted to different requirements.

[0034] According to a preferred embodiment of the invention, a first stator coil and an armature coil overlap in an initial position; a current pulse is triggered which causes a movement of the armature, so that the overlap of the first stator coil and the armature coil increases, and a further current pulse is triggered when the overlap of the first stator coil and armature coil has decreased again. One advantage of this is that in this way a relatively high torque can be generated over a relatively large angle of rotation of the armature.

[0035] According to a preferred embodiment of the invention, the rotary actuator has a rotation angle limiting device by means of which rotation of the armature relative to the stator is limited to a predetermined rotation angle range. A rotation angle limitation, however, only exists in the sense that no repeated rotational movement of the armature in one direction, as with normal motors, is intended and that repeated rotational movement of the armature in one direction is limited by the flexible electrical cables for power supply. In principle, however, only a few revolutions of the armature, e.g. one or two revolutions, may be possible if such a rotational movement is necessary in a specific application. The armature must then be rotated back to its original position accordingly. In switchgear, preferably only approx. 60° is usual if the rotary actuator is used as a main drive of a switch.

[0036] The rotation angle limiting device can be formed by one or more projections projecting from the armature, which come into contact with a stop (a physical obstacle) arranged on the stator when the armature reaches an end position, thus preventing further rotation of the armature. Alternatively, the rotation angle limiting device can be formed by pawls or springs.

[0037] In the following, the invention is explained using several embodiments with the aid of the accompanying drawing. It shows schematically and not to scale

[0038] Fig. 1 shows a known linear actuator;

[0039] Fig. 2 shows a first embodiment of the rotary actuator according to the invention; Fig. 3 shows a section of the armature of Fig. 2 transverse to the axis of rotation;

[0040] Fig. 4 shows a section of the stator of Fig. 2 transverse to the axis of rotation;

[0041] Fig. 5 shows a section of the stator and armature coils of Fig. 2 transverse to the axis of rotation;

[0042] Fig. 6 is a circuit diagram of the rotary actuator of Fig. 2;

[0043] Fig. 7 shows a section of the rotary actuator of Fig. 2 with the current directions at a first time;

[0044] Fig. 8 shows a section of the rotary actuator of Fig. 2 with the current directions at a second time;

[0045] Fig. 9 shows a time course of the current in the coils and the torque between armature and stator with different current supply directions of the coils;

[0046] Fig. 10 shows a dependence of the achievable torque on the overlap of the coils;

[0047] Fig. 11 shows a timing of current pulses;

[0048] Fig. 12 shows the torque caused by the timing of Fig. 11;

[0049] Fig. 13 shows a section of a rotary actuator with a 3-way pitch;

[0050] Fig. 14 shows a section of a rotary actuator with a 4-way pitch;

[0051] Fig. 15 shows a section through a rotary actuator with a 6-way pitch; Fig. 16 shows a second embodiment of the rotary actuator according to the invention;

[0052] Fig. 17 shows a third embodiment of the rotary actuator according to the invention;

[0053] Fig. 18 is a view of a short-circuiter;

[0054] Fig. 19 shows an exemplary design of a rotary actuator for an arc suppression short-circuiter;

[0055] Fig. 20 shows a time course of various variables with the rotary actuator sketched in Fig. 19;

[0056] Fig. 21 shows an exemplary design of a rotary actuator for a quick release for arc fault shutdown;

[0057] Fig. 22 shows a time course of various variables with the rotary actuator sketched in Fig. 21;

[0058] Fig. 23 shows a circuit breaker with a vacuum interrupter and a rotary actuator acting as an auxiliary drive of the circuit breaker;

[0059] Fig. 24 shows a circuit breaker with a vacuum interrupter and a rotary actuator acting as a main drive of the circuit breaker;

[0060] Fig. 25 is an oblique view of a rotation angle limiting device; and

[0061] Fig. 26 is a plan view of the rotation angle limiting device of Fig. 25.

[0062] Fig. 1 shows a linear actuator comprising a hollow cylindrical stator 10 and a hollow cylindrical armature 20. The armature 20 is arranged within the stator 10, where it can be moved linearly back and forth along a movement axis 100, which coincides with the rotation axes of the stator 10 and armature 20. The stator 10 has a circumferential recess (groove) on its inner circumference, in which a stator coil 11 is inserted. The armature 20 has a circumferential recess (groove) on its outer circumference, in which an armature coil 21 is inserted. By skillfully energizing the coils 11, 21, a desired linear movement of the armature 20 relative to the stator 10 can be achieved. A similar linear actuator is described, for example, in DE102011080065A1 (MSM Krystall GbR) 19.04.2012.

[0063] Fig. 2 shows a first embodiment of the rotary actuator 1 according to the invention.

[0064] The rotary actuator 1 comprises a hollow cylindrical stator 10, e.g., made of a metal, which has six longitudinal ribs 12 on its inner circumference extending along its rotational axis 2. Three stator coils 11 are wound into the spaces (grooves) between the longitudinal ribs 12. The three stator coils 11 are thus connected to the stator 10 in such a way that a force acting on the stator coils 11 is transmitted to the stator 10.

[0065] The rotary actuator 1 has a hollow cylindrical armature 20, e.g. made of a metal, which is arranged inside the stator 10 and which is rotatable about its rotation axis 2 relative to the stator 10.

[0066] The armature 20 has six longitudinal ribs 22 on its outer circumference running along its axis of rotation 2. Three armature coils 21 are wound into the spaces (grooves) between the longitudinal ribs 22. The three armature coils 21 are thus connected to the armature 20 such that a force acting on the armature coils 21 is transmitted to the armature 20. The rotary actuator 1 can be used to generate a rotary movement of a rotary shaft; for this purpose, the rotary shaft is guided through the armature, along the axis of rotation of the armature, and connected to the armature in a rotationally fixed manner, e.g. by a known tongue and groove connection. Thus, a rotation of the armature leads to a rotation of the rotary shaft.

[0067] The stator coils 11 and the armature coils 21 are fed from a voltage source in parallel or series connection because this allows relatively high shock torques to be generated.

[0068] Fig. 3 shows a section of the armature 20 transverse to the rotation axis 2. The armature 20 has six longitudinal ribs 22 on its outer circumference running along its rotation axis 2. The armature can be assembled from individual sheets to suppress eddy currents, as is known from the manufacture of electric motors.

[0069] Fig. 4 shows a section of the stator 10 transverse to the rotation axis 2. The stator 10 has six longitudinal ribs 12 on its inner circumference running along its rotation axis 2. The stator can be assembled from individual laminations to suppress eddy currents, as is known from the manufacture of electric motors.

[0070] Fig. 5 shows a section of the three stator coils 11 and three armature coils 21 transverse to the rotation axis 2. The coils 11, 21 are each wound into the recesses between the longitudinal ribs 12, 22.

[0071] Fig. 6 shows a circuit diagram of an electrical circuit 9 for the rotary actuator 1 of Fig. 2. The rotary actuator 1 of Fig. 2 has a stator 10 and an armature 20, each with three coils.

[0072] In circuit 9 there is a stator coil 11 and an armature coil

[0073] 21 is connected in series and electrically connected to a voltage source 50. Thus, the stator coil 11 and the armature coil 21 are energized if a switch 52 connected to the circuit 9 is switched to conduct current. The voltage source 50 can be designed as an electrical energy storage device 6, e.g., a capacitor, which can discharge its electrical charge into the stator coil 11 and the armature coil 21.

[0074] The circuit 9 has power lines 3 through which the stator coil 11 can be energized, and flexible lines 4, e.g., stranded wires, through which the armature coil 21 can be energized. The flexibility of the lines 4 is necessary because the armature 20 is intended to perform a rotary motion and no sliding contacts are provided.

[0075] A freewheeling path 13 is connected in parallel with the stator coil 11 and the armature coil 21, in which a freewheeling diode D is arranged. The freewheeling diode D takes over the inductive current of the coils 11, 21 during the time intervals in which the switch 52 is switched to block current. This is a standard wiring for inductive loads, here: the coils 11, 21, in order to prevent current chopping and thus overvoltages for the switch 52, e.g., a power semiconductor.

[0076] The rotary actuator also has a control unit 7 which controls the current supply to the stator coil 11 and the armature coil 21 by controlling the switch 52, causing the switch 52 to open (no current flows) or close (current flows) the circuit 9 at defined times.

[0077] Fig. 7 and Fig. 8 show a section of the rotary actuator of Fig. 2 with the current directions at two different times. The current direction is indicated by arrowheads and arrowheads: An arrowhead (dot) indicates that current is flowing out of the plane of the sheet, an arrowhead (cross) indicates that current is flowing into the plane of the sheet. The current directions in the stator 10 are the same at both times, whereas in the armature 20, opposite current directions are present at both times. Reversing the polarity of the coils can be done electronically, not with sliding contacts.

[0078] Fig. 9 shows a diagram with arbitrary units along the y-axis and time t in milliseconds along the x-axis. Curves 91 / 92 and 93 / 94 arise from different current supply directions, which leads to a left or right rotation respectively. Curve 91 shows the time course of the torque M of the armature in a first current supply direction. Curve 92 shows the time course of the current I in the armature coil in the first current supply direction. Curve 93 shows the time course of the torque M of the armature in a second current supply direction opposite to the first current supply direction. Curve 94 shows the time course of the current I in the armature coil in the second current supply direction.

[0079] Fig. 9 shows that a single current pulse 92, 94 delivers a torque pulse 91, 93 at a suitable time. The single current pulse 92, 94 can be triggered by an angle sensor which measures the angular position of the armature in relation to the stator. The torque pulse 91, 93 occurs simultaneously and without delay with the current pulse 92, 94. A positive torque pulse 93 can be used in a circuit breaker with vacuum tubes as an acceleration pulse to influence the bounce behavior or for the separating shock. A negative torque pulse 91 can be used in a circuit breaker with vacuum tubes as a braking pulse to influence the bounce behavior.

[0080] Fig. 10 shows a diagram with torque M in arbitrary units along the y-axis and the angle of rotation φ in degrees along the x-axis. The measuring points represented as stars show that a maximum negative torque is achieved at a rotation angle of approximately 30 degrees between a stator coil and an armature coil. The measuring points represented as circles show that a maximum positive torque is achieved at a rotation angle of approximately 90 degrees between a stator coil and an armature coil. This relationship can be used, for example, in a rotary actuator used as a main drive in a circuit breaker with vacuum tubes.

[0081] Fig. 11 shows a diagram with the current I in arbitrary units along the y-axis and the time t in milliseconds along the x-axis. A defined clock cycle with a period of 5 ms of the coil current 111 flowing through the stator coils and the coil current 112 flowing through the armature coils is plotted. The current 113 through the freewheeling diode D is also plotted. In order to achieve continuous movement of the armature, several current pulses in succession are necessary. The absolute current level is less important than the level of the current change dl / dt. For continuous rotation of the armature, it is therefore more effective to generate several short current pulses than one long, high current.

[0082] Fig. 12 shows a diagram with the torque M in Nm along the y-axis and the time t in milliseconds along the x-axis. Fig. 12 shows the torque induced by the timing of Fig. 11.

[0083] Fig. 13 shows a section through a rotary actuator with a 3-way pitch, Fig. 14 a section through a rotary actuator with a 4-way pitch, and Fig. 15 a section through a rotary actuator with a 6-way pitch of stator and armature. By varying the number of stator and armature coils and thus the number of pole pairs, a rotary actuator can be adapted to different requirements, e.g., torque and rotational speed.

[0084] Fig. 16 shows a second embodiment of the rotary actuator according to the invention. The outer diameter is 60 mm and the length is 75 mm. Fig. 17 shows a third embodiment of the rotary actuator according to the invention. The outer diameter is 75 mm and the length is 50 mm. By varying the dimensions and geometry of the rotary actuator, it can be adapted to different requirements, e.g., torque and rotation speed.

[0085] Fig. 18 shows a view of a short-circuiter which has three insulators 81, 82, 83 for each current phase of the current phases LI, L2, L3. By rotating a conductive contact bar 84, an electrically conductive connection can be created between the three current phases LI, L2, L3. Without a circuit breaker which de-energizes the system when the short-circuiter has been activated, the system remains live and current continues to flow. The short circuit thus created between the three current phases LI, L2, L3 de-energizes the electrical system connected to the short-circuiter and prevents greater damage. The rotation of the contact bar 84 has so far been caused by a slow rotary drive 85. A similar construction could be equipped with a fast-rotating rotary actuator according to the invention and used as a short-circuiter for arc suppression.

[0086] Fig. 19 shows an example design of a rotary actuator for a short-circuiter for arc suppression. The outer diameter is 60 mm and the length is 250 mm. The capacitor used as the voltage source has a capacitance of 8 x 560 pF at a voltage of 360 V.

[0087] Fig. 20 shows a diagram with arbitrary units along the y-axis and time t in milliseconds along the x-axis. Plotted for the rotary actuator sketched in Fig. 19 are the time profiles of a voltage 71, a first current 72, a second current 73, a torque 74, a tenth of the angular velocity 75, a hundredth of the angle of rotation 76, and a tenth of the angular acceleration 77. The resulting surge current has a strength of 800 A, which allows a maximum torque of 400 Nm to be generated within one millisecond.

[0088] Fig. 21 shows an example design of a rotary actuator for a quick-action trip device for arc fault protection. The outer diameter is 25 mm and the length is 50 mm. The capacitor used as the voltage source has a capacitance of 560 pF at a voltage of 360 V.

[0089] Fig. 22 shows a diagram with arbitrary units along the y-axis and time in milliseconds along the x-axis. Plotted for the rotary actuator sketched in Fig. 21 are the time profiles of a voltage 71, a tenth of a first current 72, a tenth of a second current 73, a torque 74, an angular velocity 75, a rotation angle 76, and an angular acceleration 77. The resulting surge current has a strength of 700 A, allowing a maximum torque M of approximately 25 Nm to be generated within approximately 200 microseconds.

[0090] Figures 19 to 20 and figures 21 to 22 show different embodiments for different torque-time curves.

[0091] Fig. 23 shows a switch 201 of a vacuum interrupter, as described, for example, in the Siemens manual "Instruction Manual, Type 3AH35-MA vacuum circuit breaker magnetic-actuator operator module, Installation, operation, maintenance", Article No. E50001-F710-K378-V6-4A00, Published by Siemens Industry, Inc., Wendell, North Carolina, 27591, USA, 2016. The vacuum interrupter is a component of a circuit breaker. The switch 201 has two electrical switching contacts 204, 205, namely a fixed contact 204 and a moving contact 205, which are arranged in an evacuated switching chamber (not shown) of the vacuum interrupter. The switching contacts 204, 205 are designed as pressure contacts, ie to form a current-carrying contact between the switching contacts 204, 205, the switching contacts 204, 205 are pressed against each other.The fixed contact 204 is located at one end of a fixed contact rod 206, the moving contact 204 at one end of a moving contact rod 207, which is slidably guided, vacuum-tightly sealed by a metal bellows (not shown), and led out of the switching chamber of the vacuum interrupter through a cover (not shown). By means of the moving contact rod 207, the moving contact 205 can be brought into galvanic contact with the fixed contact 204 in a closing process and separated from the fixed contact 204 in an opening process to such an extent that a sufficient safety distance exists between the two contacts 204, 205 to prevent arcing of the voltage. The distance between contacts 204, 205 must be large enough so that the arc is extinguished when the current passes through zero and that the arc is not reignited when the voltage increases again.

[0092] The axial movement of the moving contact rod 207 is effected by a magnetic drive 203 serving as the main drive of the vacuum interrupter, in that an armature 224 of the magnetic drive 203, designed as a plunger, is adjusted between two end positions by interaction with a permanent magnet PM and a magnetic coil EM of the magnetic drive 203: for this purpose, an axial movement of the armature 224 is deflected by means of a transmission gear 202 into an axial movement of the moving contact rod 207. Fig. 23 shows that a second end position of the armature 224 corresponds to an open contact position of the switching contacts 204, 205.

[0093] The transmission gear 202 has an angular three-bar link 218 which is connected to the moving contact rod 207 via a first joint 211. The three-bar link 218, which is rotatably mounted in a second joint 212, is connected to a coupling rod 219 via a third joint 213. The coupling rod 219 has, in the manner of a telescopic tube, an outer tube and an inner tube which is mounted axially displaceably in the outer tube, the axial displacement of which against one another takes place under the influence of a contact pressure spring 208, which is designed as a spiral spring which is clamped between two spring support elements formed on the outer and inner tubes; coupling rods of this type are found as spring elements, for example in the vehicle sector.

[0094] Switches with pressure contacts, which include vacuum switches in particular, require a contact pressure spring which constantly maintains the pressure required for current transfer between the switching contacts when the switch is switched on (switch contacts closed), known as the contact force. The contact force is built up when the kinematic chain is in its end position by compressing the contact pressure spring. The contact pressure spring is located at a suitable point in the mechanism provided for transmitting the drive forces to the switching contacts and has a preload which is designed in such a way that the spring characteristic builds up the required contact force with the spring travel. During the switching-on process, this preload is overcome when the pressure contacts come into contact, resulting in a steep increase in the force-travel curve of the drive device.After overcoming the pre-tension of the contact pressure spring, it is tensioned even further by the so-called through-stroke so that the desired or required contact force is still present even when the contacts wear out or burn-off occurs.

[0095] The coupling rod 219 is connected via a fourth joint 214 to a lever member 220, which is fixed in a rotationally fixed manner on a rotary shaft 209 rotatably mounted in a fifth joint 215; the fifth joint 215, which serves as the bearing point for the rotary shaft 209, is also simply referred to as a bearing. The lever member 220 is also connected via a sixth joint 216 to an articulated rod 221, which in turn is connected via a seventh joint 217 to a drive rod 222. The drive rod 222 itself is fixed to the armature 224. In addition to the magnetic drive 203, which serves as the main drive and acts on the rotary shaft 209 via the articulated rod 221 and the lever member 220, the circuit breaker also has a rotary actuator 1 according to the invention, which functions as an additional drive for the circuit breaker. The armature of the rotary actuator 1 is arranged in a rotationally fixed manner on and coaxial with the rotary shaft 209.

[0096] The vacuum switching unit has a switch 201 for each of the three phases LI, L2, L3 of a three-phase outer conductor current, whereby to simplify the illustration only the switch 201 of one of the three phases LI, L2, L3 is shown in Fig. 23. All three moving contacts 205 of the vacuum switching unit are actuated jointly by the magnetic drive 203. For this purpose the rotating shaft 209 carries three lever members 220, of which to simplify the illustration only a single lever member 220 is shown in Fig. 23. The moving contact 205 of the contact pair 204, 205 of one of the three switches 201 of the vacuum switching unit is actuated by each of the three lever members 220; the three switches 201 of the vacuum switching unit therefore open and close simultaneously.Simultaneous opening and closing of the switching contacts is the "usual" case. However, there is also the application of phase-selective switching using separate drives, in which case the switching action of the three phases occurs at different times. The invention can, of course, also be implemented with such a phase-selective switch.

[0097] For the sake of completeness, it should be noted here that there are also single-pole drives in which not all three moving contacts of the vacuum switching unit are actuated by a common magnetic drive, but in which each phase has a separate drive and a separate kinematic chain. There are also single-phase and two-phase switching devices. The invention can of course also be implemented with such a single-pole drive, a single-phase or a two-phase switching device. Fig. 24 shows a circuit breaker with at least one vacuum interrupter 1 which has a rotary actuator 1 according to the invention. The circuit breaker shown in Fig. 24 differs from the circuit breaker shown in Fig. 23 in that the rotary actuator 1 acts as a main drive of the circuit breaker and that a movement of the moving contact 205 of the vacuum interrupter 1 is brought about by a rotation of the rotary actuator 1. The circuit breaker shown in Fig.The magnetic drive 203 shown in Fig. 23 is not present in the circuit breaker shown in Fig. 24.

[0098] Fig. 25 shows an oblique view of a rotation angle limiting device 5 of a rotary actuator 1, which has a hollow cylindrical stator 10 and a hollow cylindrical armature 20. On one end face of the rotary actuator 1, the stator 10 has two stop lugs (stops) 61, 63 which are fixed to the end face of the stator 10. On the same end face of the rotary actuator 1, the armature 20 has a lug (stop) 62 which is fixed to the end face of the armature 20. The range of rotation of the armature 20 about the axis of rotation 2 is limited by the stop lugs 61, 63 of the stator 10: A rotation in a first direction 25 is limited by the lug 62 of the armature 20 stopping against the first stop lug 61 of the stator 10; a rotation in a second direction 26 is limited by a stop of the nose 62 of the armature 20 on the second stop nose 63 of the stator 10.

[0099] Fig. 26 shows the rotation angle limiting device 5 of the rotary actuator 1 described in Fig. 25 in a plan view. This shows the position when the nose 62 of the armature 20 strikes the first stop nose 61 of the stator 10.

Claims

Patent claims 1. Rotary actuator (1) comprising: - a stator (10), - at least one stator coil (11) connected to the stator (10) such that a force acting on the stator coil (11) is transmitted to the stator (10); - an armature (20) rotatable about an axis of rotation (2) relative to the stator (10), - at least one armature coil (21) connected to the armature (20) in such a way that a force acting on the armature coil (21) is transmitted to the armature (20); - electrical lines (3) through which at least one stator coil (11) can be supplied with current, and - electrical lines (4) through which the at least one armature coil (21) can be supplied with current.

2. Rotary actuator according to claim 1, wherein the at least one stator coil (11) and the at least one armature coil (21) are connected in series.

3. Rotary actuator according to one of the preceding claims, wherein the number of pole pairs of the armature (20) and the stator (10) are the same.

4. Rotary actuator according to one of the preceding claims, comprising an electrical energy storage device (6) which can discharge its charge into the at least one stator coil (11) and / or at least one armature coil (21).

5. Rotary actuator according to one of the preceding claims, comprising a control unit (7) which controls the energization of the at least one stator coil (11) and the at least one armature coil (21).

6. Rotary actuator according to claim 5, wherein the control unit (7) is configured to control an electronic reversal of the coils (11, 21).

7. Rotary actuator according to one of the preceding claims, wherein the at least one stator coil (11) and the at least one armature coil (21) overlap radially.

8. Rotary actuator according to one of the preceding claims, comprising a rotation angle limiting device (5) by which a rotation (25, 26) of the armature (20) relative to the stator (10) is limited to a defined rotation angle range.

9. A method for operating the rotary actuator according to any one of claims 1 to 8, wherein a current pulse triggered by an angular position (cp) of the armature (20) relative to the stator (10), causes a braking or acceleration pulse.

10. The method according to claim 9, wherein several current pulses in succession cause a continuous movement of the armature (20).

11. The method according to claim 9 or 10, wherein the one or more current pulses cause a current change dl / dt.

12. Method according to one of claims 9 to 11, wherein in an initial position a first stator coil (11) and an armature coil (21) overlap, a current pulse is triggered which causes a movement of the armature (20) so that the overlap of the first stator coil (11) and the armature coil (21) increases and a further current pulse is triggered when the overlap of the first stator coil (11) and armature coil (21) has decreased again.

13. Switching device with at least one switch (201), comprising a rotary shaft (209) and a main drive (203) acting on the rotary shaft (209), wherein a movement of a moving contact (205) of the at least one switch (201) is caused by a rotation of the rotary shaft (209), further comprising a rotary actuator (1) according to one of claims 1 to 8, wherein the rotary actuator (1) functions as an additional drive of the switch (201) and the armature (20) of the rotary actuator (1) is arranged in a rotationally fixed manner on and coaxial with the rotary shaft (209).

14. Switching device with at least one switch (201), comprising a rotary actuator (1) according to one of claims 1 to 8, wherein the rotary actuator (1) functions as a main drive of the switch (201) and wherein a movement of a moving contact (205) of the at least one switch (201) is caused by a rotation of the rotary actuator (1).

15. Short-circuiter, comprising a rotary actuator (1) according to one of claims 1 to 8, wherein a movement of a closing contact of the short-circuiter is caused by the rotary actuator (1).

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