Drive comprising an electromagnet and a rotor rotatably mounted relative to the electromagnet

Abstract

Drive comprising an electromagnet and a rotor rotatably mounted relative to the electromagnet, wherein permanent magnets are arranged on the rotor, wherein the axial or radial component of the magnetic field strength generated by the permanent magnets, or an average value of this component decreases in the circumferential direction, in particular decreases monotonically, until a jump region is reached and increases in the circumferential direction in the jump region.

Description

[0001] The invention relates to a drive comprising an electromagnet and a rotor rotatably mounted relative to the electromagnet.

[0002] It is generally known that an electric motor drive has a rotatably mounted rotor.

[0003] From DE 27 44 979 A1, a magnetic motor is known as the closest prior art.

[0004] A magnetic motor is also known from DE 27 06 691 A1.

[0005] A rotor of an electric motor is known from DE 10 2017 216 094 A1.

[0006] A rotor is known from KR 10 2015 0 122 445 A.

[0007] A BLDC motor arrangement is known from US 2013 / 0 002 080 A1.

[0008] A rotor of an electric motor is known from CN 1 09 962 544 A.

[0009] From DE 100 18 175 A1 a circuit arrangement for operating a highly dynamic electromagnetic lifting armature actuator is known.

[0010] The invention is therefore based on the object of designing an energy-efficient electric motor, in particular an electric motor with high efficiency.

[0011] According to the invention, the object is achieved by the drive according to the features specified in claim 1.

[0012] Important features of the invention in the drive, comprising an electromagnet and a rotor rotatably mounted relative to the electromagnet, are that permanent magnets are arranged on the rotor, wherein, in particular in the area covered by the electromagnet in the axial direction, the axial or radial component of the magnetic field strength generated by the permanent magnets or an average value of this component decreases in the circumferential direction, in particular decreases monotonically, up to a discontinuity area and increases in the circumferential direction in the discontinuity area, in particular wherein the electromagnet has a winding wound around a ferromagnetic coil core and / or one or more windings wound around a permanent magnet, in particular wherein the axial direction is aligned parallel to the axis of rotation of the rotor and / or wherein the radial direction and the circumferential direction are related to the axis of rotation of the rotor.

[0013] The advantage here is that the permanent magnets are arranged in such a way that the component in the circumferential direction decreases, at least on average, over a circumferential angular range. Thus, when the electromagnet is energized, a torque is generated that sets the rotor in rotation because the electromagnet is pulled in the direction of the decreasing component, i.e., into an area with lower field line density. This means that the permanent magnets closest to the electromagnet experience a corresponding force, which causes the torque. The movement of the rotor can thus be accelerated because the electromagnet, so to speak, repels the rotor in such a way that the electromagnet moves into an area with lower field line density.

[0014] If a winding is provided around a ferromagnetic coil core, a constant voltage can be used for the winding, which only needs to be interrupted or reversed to overcome the respective jump area.

[0015] Alternatively or additionally, a winding around a permanent magnet can also be provided, which only needs to be operated with a pulse voltage, whereby the voltage pulse is provided in the jump point area.

[0016] Another advantage is that while the rotor requires permanent magnets, i.e., magnetized material, no other electrically conductive materials are required. Metallic fasteners, such as sheet metal strips and rings, are not required for its operation. For example, the rotor can be made from a renewable raw material such as wood or similar, and the permanent magnets are bonded to the raw material.

[0017] In an advantageous embodiment, the axial or radial component of the magnetic field strength generated by the permanent magnets, or the mean value of this field strength, increases in the discontinuous region. The advantage here is that the field strength is a periodic function of the circumferential angle.

[0018] In an advantageous embodiment, the permanent magnets are all arranged at the same radial distance from the rotor's rotational axis. This has the advantage that the torque generated by the rotor is evenly distributed.

[0019] In an advantageous embodiment, the mean value is a moving average calculated in the circumferential direction. This is advantageous because the fluctuations caused by the discrete permanent magnet structure are averaged out. This means that the magnitude of the component decreases in the circumferential direction if the discrete distribution of the permanent magnets is not taken into account, but rather a corresponding homogenization is applied.

[0020] In an advantageous embodiment, the amount of the component is a periodic function of the circumferential angle, In particular, with a period length of 360° / N, where N is the number of discontinuous regions. The advantage here is that the magnitude of the component decreases up to the discontinuous region and only increases in the discontinuous region, i.e., in a smaller circumferential angle range than in the circumferential angle range before the discontinuous region, in which the magnitude decreases.

[0021] In an advantageous embodiment, the permanent magnets are evenly spaced from each other in the circumferential direction. This is advantageous because it allows for simple manufacturing.

[0022] In an advantageous embodiment, the permanent magnets are magnetized in the radial direction or the permanent magnets are magnetized in the axial direction. This is advantageous because reducing the magnitude of the circumferential component is easily achievable.

[0023] In an advantageous embodiment, the permanent magnets are arranged in two rows, the two rows being axially spaced from each other, In particular, the two rows each extend circumferentially. This is advantageous because it allows for simple manufacturing.

[0024] In an advantageous embodiment, sheet metal strips, in particular sheet metal strips extending in the axial direction, each cover at least one respective pair of permanent magnets, in particular coming from the radial direction. This advantageously ensures that the permanent magnets are securely held on the rotor.

[0025] In an advantageous embodiment, the sheet metal strips are held by two rings pushed onto the rotor, the ring axes of the two rings are aligned coaxially to the axis of rotation of the rotor, The permanent magnets are arranged axially between the two rings. This provides the advantage of stable holding of the permanent magnets and the sheet metal strips.

[0026] In an advantageous design, the sheet metal strips are firmly bonded to the rings. This provides the advantage of ensuring the sheet metal strips are held securely.

[0027] In an alternative advantageous embodiment, the rotor has at least one cylindrical, in particular hollow-cylindrical, layer of permanent magnet material, whose cylinder axis is aligned coaxially with the axis of rotation of the rotor, The permanent magnets are created by magnetizing the permanent magnet material, particularly radially. This allows for simple manufacturing by magnetizing the layer accordingly during production. The layer is aligned coaxially with the rotor's rotational axis.

[0028] In an advantageous embodiment, the axial distance between the permanent magnets or the rows of permanent magnets decreases monotonically, in particular strictly monotonically, with increasing circumferential angle up to the point or one of the discontinuous areas. This is advantageous because it is easy to manufacture.

[0029] In an advantageous embodiment, the electromagnet is electrically supplied from a DC voltage source via a controllable polarity reversal circuit, The DC voltage source comprises a double-layer capacitor, in particular a supercapacitor, powercap, or ultracapacitor, and / or a battery cell, in particular one with low internal resistance. This is advantageous in that rapid current dissipation in the jump region is possible, since the double-layer capacitor or the battery cell has or has a very low internal resistance.

[0030] In an advantageous embodiment, a control electronics of the drive controls the polarity reversal circuit depending on the signals of an angle sensor of the drive, In particular, the angle sensor is designed to detect the angular position of the rotor. The advantage here is that precise current control can still be achieved at different rotor speeds.

[0031] Further advantages emerge from the dependent claims. The invention is not limited to the combination of features in the claims. Further possible combinations of claims and / or individual claim features and / or features of the description and / or the figures will become apparent to those skilled in the art, particularly from the problem and / or the problem posed by comparison with the prior art.

[0032] The invention will now be explained in more detail using schematic illustrations: In the Fig. 1 shows an electric motor according to the invention with an electromagnet 4 in an oblique view. In the Fig. 2 shows a schematic representation of an electronic circuit for supplying the electromagnet 4.

[0033] As shown in the figures, the electric motor has a rotatably mounted rotor 1 which is equipped with permanent magnets 2 such that the magnetic field strength generated by the permanent magnets 2 has, at least in a first circumferential angle range, an axial or radial component which decreases in magnitude in the circumferential direction, in particular the radial or axial component of the field strength generated by the permanent magnets 2 has a decreasing magnitude in the circumferential direction, i.e. with increasing circumferential angle.

[0034] The axial direction is aligned parallel to the rotational axis of rotor 1. The circumferential direction is related to the rotational axis of rotor 1. The radial direction is also related to the rotational axis of rotor 1.

[0035] The magnitude of the above-mentioned component is understood here to be a moving average of this component formed in the direction of the circumferential angle, since the magnitude fluctuations generated by the use of individual permanent magnets 2 must be averaged out.

[0036] An electromagnet 4 is arranged stationary. Thus, the rotor 1 is arranged rotatably relative to the electromagnet 4.

[0037] Preferably, the magnetic field generated by the electromagnet 4 when a coil of the electromagnet 4 is energized is directed radially with respect to the axis of rotation of the rotor 1.

[0038] As a result of the circumferentially decreasing magnitude of the magnetic field generated by the permanent magnets, a tangentially directed force is introduced into rotor 1, in particular, a torque is generated. This is because rotor 1 is driven into an angular position in which the field strength of the permanent magnets accommodated by the rotor decreases or is minimal.

[0039] At a first end of the circumferential angle range in the circumferential direction, for example, after 360°, there is no further decrease in the field strength in the circumferential direction, but rather an increase in the field strength. At this point in the magnitude of the circumferential angle-dependent curve of the field strength generated by the permanent magnets, particularly the axial or radial component of the field strength, at the circumference of the electric motor, the magnitude increases sharply in the circumferential direction, i.e., with increasing circumferential angle. This is because the arrangement of the permanent magnets is a periodic function of the circumferential angle in the circumferential direction.

[0040] What is important with this field strength curve is that the radial or axial component of the magnetic field strength generated by the permanent magnets 2 arranged on the rotor 1 decreases with increasing circumferential angle, as long as the respective jump point is not reached.

[0041] The permanent magnets 2 are arranged in two rows, spaced apart axially. The spacing is a monotonically increasing function of the circumferential angle until the respective jump point is reached.

[0042] The permanent magnets 2 are either all magnetized in the radial direction or all in the axial direction.

[0043] When energized, the electromagnet 4 generates a radially directed magnetic field, exerting a torque on the rotor 1. The rotational angle of the rotor 1 is detected by the angle sensor 10. Thus, the energization of the electromagnet 4 can be carried out depending on the detected angle value. When the detected angle value of the rotor 1 reaches the jump point or an area around the jump point, the energization of the electromagnet 4 is reduced or stopped. Thus, the rotor 1 overcomes the jump point with its mechanical inertia, so that after overcoming the jump point, the electromagnet is switched on again, thus continuing to supply the torque to the rotor 1.

[0044] The higher the moment of inertia of rotor 1, the smaller the rotational speed fluctuations at the jump point.

[0045] As in the Fig. As shown in Figure 1, the permanent magnets 2 are arranged in pairs, with each pair being arranged at the same circumferential angular position and the two permanent magnets 2 of the respective pair being axially spaced from each other. This spacing of the respective pair increases monotonically in the circumferential direction, i.e., with increasing circumferential angle, until the jump point is reached, at which the spacing drops back to its smallest value, before increasing again with further increasing circumferential angle.

[0046] Preferably, the pairs are evenly spaced from each other in the circumferential direction.

[0047] As in Fig.As shown schematically in Figure 2, the angle sensor 10 detects the rotational position of the rotor 1. The angle values ​​thus detected are processed by the evaluation electronics 9 and made available to the control electronics 8, which, via the controls (6, 7), in particular driver circuits, controls two half-bridges of a polarity reversal circuit, which thus makes the DC voltage available to the coil L1 of the electromagnet 4 directly or inverted, depending on the detected angle value of the rotor 1.

[0048] As long as the jump point is not reached, the DC voltage drives a current through coil L1. Upon reaching the jump point, the voltage applied to coil L1 is reversed, thus reducing the current and thus also reducing the magnetic field. Once the jump point is overcome, the polarity is reversed again, thus rebuilding the current.

[0049] Alternatively, the current supply to the permanent magnet 2 is only required in the jump area, in particular since a rotational movement of the rotor is caused by the design of the arrangement of the magnets.

[0050] By using a voltage source with a particularly low internal resistance, a particularly rapid reduction of the current and thus of the magnetic field in the area of ​​the jump is possible. For example, a double-layer capacitor can be used as the voltage source, thus enabling suitable, particularly low-loss, operation even at high speeds.

[0051] Alternatively, the current supply is only activated in the jump area, since a torque acting on the rotor and thus a rotational movement of the rotor can be effected due to the design of the arrangement of the magnets.

[0052] In further embodiments according to the invention, the electromagnet 4 is arranged such that it generates an axially directed magnetic field in the region between the permanent magnets 2.

[0053] In further embodiments according to the invention, instead of the period length of 360°, another value is used, for example 360° / N, where N is a natural number and is the number of circumferential regions and thus also indicates the number of discontinuities of the magnetic field strength on the circumference of the rotor 1.

[0054] When N = 1, the axial distance between the respective pairs of permanent magnets 2 increases in the circumferential direction. Thus, the circumferential or radial component of the magnetic field generated by the permanent magnets 2 becomes increasingly weaker in the circumferential direction.

[0055] Each of the jump points is not a mathematical point, but covers a circumferential angle range, which is referred to here as the jump point range.

[0056] The circumferential direction here is directed in the direction of rotation, i.e. in the direction of the decreasing axial distance between the two rows of permanent magnets.

[0057] The angle sensor 10 preferably has a revolution counter 14, in particular a rotor position sensor, which detects the passing of a sensor flag 13 arranged in a rotationally fixed manner on the rotor 1. If only a single discontinuity is present on the circumference of the rotor, the DC voltage applied to the electromagnet 4 is reversed upon detection of the sensor flag 13 and is reversed again after overcoming the discontinuity area.

[0058] The permanent magnets 2 are radially covered and thus held by axially directed sheet metal strips 11, with the permanent magnets 2 additionally adhesively bonded to the rotor 1 and / or the sheet metal strips 11. The sheet metal strips are attached to the rotor 1 by means of rings 12. The area covered by the sheet metal strips 11 in the axial direction encompasses the area covered by the permanent magnets 2 in the axial direction.

[0059] The electromagnet preferably has a ferromagnetic coil core, in particular made of iron sheets, and an electrically energizable winding.

[0060] In further embodiments according to the invention, the electromagnet 4 has a permanent magnet as its coil core, around which one or more windings are wound in such a way that the magnetic field generated by the permanent magnet can be weakened by means of the electrically energized windings. Thus, upon reaching the respective discontinuity point or discontinuity region, a brief weakening of the magnetic field can be achieved by energizing the winding or windings, which allows the discontinuity region to be overcome. Thus, only one energization of the winding or windings in the discontinuity region is necessary, i.e., a pulsed energization.

[0061] In further embodiments according to the invention, the electromagnet 4 has a permanent magnet as a coil core, around which one or more windings are wound such that the magnetic field generated by the permanent magnet can be amplified by means of the electrically energized windings. Thus, upon reaching the respective jump point or the respective jump point region, a brief amplification of the magnetic field can be achieved by energizing the winding or windings, which makes it possible to overcome the jump point region. Thus, only one energization of the winding or windings in the jump point region is necessary, i.e., a pulsed energization. In particular, a torque can still be generated while passing through the jump point region.

[0062] For example, a first of the windings is wound around the north pole of the permanent magnet and a second of the windings is wound around the south pole.

[0063] Combinations of the above-mentioned embodiments are also possible.

[0064] In further embodiments of the invention, the opposite direction is used instead of the direction directed in the circumferential direction. List of reference symbols 1 rotor 2 permanent magnets 3 retaining plate 4 Electromagnet 5 Voltage source, especially with very low internal resistance 6 Control 7 Control 8 Control electronics 9 Evaluation electronics 10 Angle sensor 11 metal strips 12 rings 13 Donor flag 14 revolution counters L1 Coil of electromagnet 4 S1 controllable semiconductor switch S2 controllable semiconductor switch S3 controllable semiconductor switch S4 controllable semiconductor switch QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 27 44 979 A1

[0003] DE 27 06 691 A1

[0004] DE 10 2017 216 094 A1

[0005] KR 10 2015 0 122 445 A

[0006] US 2013 / 0 002 080 A1

[0007] CN 1 09 962 544 A

[0008] DE 100 18 175 A1

[0009]

Claims

[1] Drive, comprising an electromagnet and a rotor rotatably mounted relative to the electromagnet, permanent magnets are arranged on the rotor, characterized by , that, in particular in the area covered by the electromagnet in the axial direction, the axial or radial component of the magnetic field strength generated by the permanent magnets or an average value of this component decreases in the circumferential direction, in particular decreases monotonically, up to a discontinuity area and increases in the circumferential direction in the discontinuity area, in particular wherein the electromagnet has a winding wound around a ferromagnetic coil core and / or one or more windings wound around a permanent magnet, in particular wherein the axial direction is aligned parallel to the axis of rotation of the rotor and / or wherein the radial direction and the circumferential direction are related to the axis of rotation of the rotor. [2] Drive, comprising an electromagnet and a rotor rotatably mounted relative to the electromagnet, permanent magnets are arranged on the rotor, characterized by , that, in particular in the area covered by the electromagnet in the axial direction, the axial or radial component of the magnetic field strength generated by the permanent magnets or an average value of this component decreases in the circumferential direction, in particular decreases monotonically, up to a discontinuity area and increases in the circumferential direction in the discontinuity area, in particular wherein the electromagnet has a winding wound around a ferromagnetic coil core and / or one or more windings wound around a permanent magnet, in particular wherein the axial direction is aligned parallel to the axis of rotation of the rotor and / or wherein the radial direction and the circumferential direction are related to the axis of rotation of the rotor, wherein sheet metal strips extending in the axial direction each cover at least one respective pair of the permanent magnets, in particular coming from the radial direction, where the sheet metal strips are designed as stamped parts or as stamped and bent parts, the sheet metal strips are held by two rings pushed onto the rotor, wherein the ring axes of the two rings are aligned coaxially to the axis of rotation of the rotor, wherein the permanent magnets are arranged in the axial direction between the two rings. [3] Drive according to claim 1 or 2, characterized by that the permanent magnets are all arranged at the same radial distance from the axis of rotation of the rotor. [4] Drive according to one of the preceding claims, characterized by that the mean is a circumferential moving average. [5] Drive according to one of the preceding claims, characterized by , that the magnitude of the component is a periodic function of the circumferential angle, in particular with the period length 360° / N, where N is the number of jump regions. [6] Drive according to one of the preceding claims, characterized by that the permanent magnets are evenly spaced from each other in the circumferential direction. [7] Drive according to one of the preceding claims, characterized by , that the permanent magnets are magnetized in the radial direction or that the permanent magnets are magnetized in the axial direction. [8] Drive according to one of the preceding claims, characterized by , that the permanent magnets are arranged in two rows, the two rows being axially spaced from each other, in particular wherein the two rows each run in the circumferential direction. [9] Drive according to one of the preceding claims, characterized by , that Sheet metal strips, in particular sheet metal strips extending in the axial direction, each cover at least one respective pair of the permanent magnets, in particular coming from the radial direction, in particular wherein the sheet metal strips are designed as stamped and bent parts. [10] Drive according to one of the preceding claims, characterized by , that the sheet metal strips are held by two rings pushed onto the rotor, wherein the ring axes of the two rings are aligned coaxially to the axis of rotation of the rotor, wherein the permanent magnets are arranged in the axial direction between the two rings. [11] Drive according to one of the preceding claims, characterized by that the sheet metal strips are firmly connected to the rings. [12] Drive according to one of claims 1 to 5, characterized by , that the rotor has at least one cylindrical layer of permanent magnet material, whose cylinder axis is aligned coaxially with the axis of rotation of the rotor, wherein the permanent magnets are produced by, in particular radially directed, magnetization of the permanent magnet material. [13] Drive according to one of the preceding claims, characterized bythat the axial distance of the permanent magnets or the rows of permanent magnets from each other decreases monotonically, in particular strictly monotonically, with increasing circumferential angle up to the or one of the discontinuity areas. [14] Drive according to one of the preceding claims, characterized by , that the electromagnet, in particular the winding or windings of the electromagnet, is electrically supplied from a DC voltage source via a controllable polarity reversal circuit, in particular, wherein the DC voltage source comprises a double-layer capacitor, in particular a supercapacitor, powercap or ultracap, and / or a battery cell, in particular with low internal resistance. [15] Drive according to one of the preceding claims, characterized by , that a control electronics of the drive controls the polarity reversal circuit depending on the signals of an angle sensor of the drive, in particular wherein the angle sensor is designed to detect the angular position of the rotor.

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