Magnetic gear

Abstract

For a rotary drive with low torque ripple, the invention proposes a magnetic gear (1) with helical magnetic poles (n, s, N, S) of a low-pole and a high-pole, rotatable gear element (2, 3).

Description

[0001] The invention relates to a magnetic gear having the features of the preamble of claim 1 or the features of the preamble of the independent claim 2.

[0002] Unlike a gear transmission, which transmits torque between two gears mechanically by transmitting force between teeth of intermeshing gears, a magnetic transmission transmits torque between rotatable gear elements by magnetic forces, whereby a transmission ratio, i.e. speeds in a certain ratio to one another, is possible between a driven and an output gear element of the magnetic transmission.

[0003] A magnetic gear is known from published patent application DE 44 05 701 A1. The known magnetic gear comprises three gear elements arranged coaxially and coaxially within one another and rotatable against one another. One of these elements is driven, another is non-rotatable, and the third forms an output. An inner one of the three gear elements of the known magnetic gear comprises two semi-cylindrical shell-shaped permanent magnets arranged on a tubular magnetic yoke, so that the inner gear element has a magnetic north pole and a magnetic south pole on its outer circumference, each extending over half the circumference. The inner gear element thus has a pair of magnetic poles.

[0004] An outer one of the three gear elements of the known magnetic gear is tubular and has permanent magnets on an inner circumference of a tubular magnetic yoke, so that the outer gear element has alternating magnetic north poles and magnetic south poles on its inner circumference.

[0005] A tubular modulator made of a magnetically conductive material is arranged between the inner gear element and the outer gear element as a third gear element. The modulator has a smooth inner circumferential surface facing the two magnetic poles of the inner gear element. On an outer circumference, the modulator of the known magnetic gear has rectangular teeth whose tooth tips are flat surfaces that form pole shoes facing the permanent magnets or the magnetic poles on the inner circumference of the tubular, outer gear element. The modulator conducts magnetic field lines from the magnetic poles of the inner gear element to the magnetic poles of the outer gear element, and vice versa.A gear ratio results from the number of magnetic pole pairs of the inner gear element, the number of magnetic pole pairs of the outer gear element and the number of pole shoes of the modulator arranged between the inner gear element and the outer gear element.

[0006] The magnetic poles and the pole shoes of the gear elements of the known magnetic gear run straight in a direction parallel to the axis.

[0007] The maximum transmittable torque of a magnetic gear is limited by the maximum magnetic forces between the magnetic poles and the pole shoes of the gear elements.

[0008] One disadvantage of the conventional magnetic gear is torque ripple in the output. As with an electric motor, in addition to a torque-generating component, which in an electric motor is a rotating field generated by a stator that drives a rotor, and in a magnetic gear, a rotatingly driven gear element, a magnetic gear also contains components that generate additional cogging torque. In an electric motor, these are magnets that short-circuit via the stator's pole pieces. In a non-driven magnetic gear with freely rotatable gear elements, the magnetic forces acting between the gear elements cause them to rotate into an equilibrium position, i.e., into a specific angular position of the gear elements relative to one another.If one gear element is driven in rotation without the other two gear elements being held or braked, the gear elements rotate together in the equilibrium position without twisting against each other. This changes if one gear element is held non-rotatably while another gear element is driven in rotation and torque is picked up from yet another gear element, i.e. the output gear element is braked. The driven and output gear elements then rotate at different speeds in the ratio of a gear ratio of the magnetic gear. When the gear elements rotate relative to each other, the gear elements rotate against each other from their equilibrium position, with the magnetic forces acting between the gear elements acting on the gear elements back to the equilibrium position.This creates effects such as short-circuiting the magnets of two gear elements via the pole pieces of the gear element forming the modulator and weakening the magnetic fields of opposing magnetic poles, which generate a cogging torque (so-called "ripples") superimposed on the torque transmission. As a result, the torque transmitted between the gear elements changes continuously during rotation. These torque fluctuations, especially in the output, are undesirable for most applications. A torque as uniform as possible at the output is desirable.

[0009] German Patent Application DE 10 2015 103 565 A1 discloses a solution for reducing torque ripples. This involves offsetting one of the gear elements of the magnetic gear. "Offset" means that the magnetic poles or pole shoes of a gear element are not axially parallel, but rather helically aligned. This means that the magnetic poles or pole shoes are offset in a circumferential direction along their axial length. This magnetically clamps the gear elements of the magnetic gear against each other. In non-driven, torque-free gear elements, the magnetic poles and pole shoes are in the equilibrium position only at one axial point of the magnetic gear.To the side of this point, the magnetic poles and pole pieces are located just before or just behind the equilibrium position, i.e., to the side of this position, magnetic forces act between the magnetic poles and the pole pieces of the gear elements, forcing the gear elements into the equilibrium position. Torques between the gear elements of the magnetic gear are oppositely directed on both sides next to the point where the gear elements are in the equilibrium position. Although this reduces torque ripples, i.e. the fluctuation of the torque transmitted between the gear elements of the magnetic gear during rotation, it also reduces the maximum transmittable torque. Depending on the angle of inclination of the magnetic poles or pole pieces, the maximum transmittable torque can be reduced to less than 60% of the original value.

[0010] German Patent Application DE 10 2012 101 918 A1 discloses a magnetic gear with three gear elements arranged coaxially and coaxially within one another and rotatable against one another. An outer one of the three gear elements is tubular and has strip-shaped permanent magnets with alternating polarity in the circumferential direction, which extend axially parallel over an axial length of the outer gear element.

[0011] An inner of the three gear elements of the known magnetic gear has narrow, semi-cylindrical shell-shaped permanent magnets in the axial direction, which extend over 180° in the circumferential direction. Permanent magnets arranged next to one another are offset from one another in the circumferential direction to such an extent that the permanent magnets are offset by 360° over the axial length of the inner gear element.

[0012] A tubular modulator arranged between the inner and outer gear elements has magnetic conductors whose pole pieces face the permanent magnets of the inner and outer gear elements in such a way that they conduct magnetic field lines back and forth between the permanent magnets of the inner and outer gear elements. In the axial direction, the modulator has the same number of magnetic conductors arranged side by side as the inner gear element has permanent magnets arranged side by side. In the circumferential direction, the adjacent magnetic conductors of the modulator are offset from one another to such an extent that, over the axial length of the modulator, the magnetic conductors are offset by 360° divided by their number in the circumferential direction.

[0013] The object of the invention is to propose a magnetic gear with a low torque ripple and high transmittable torque.

[0014] This object is achieved according to the invention by the features of claim 1 or the independent claim 2.

[0015] The magnetic gear according to the invention with the features of claim 1 comprises three gear elements arranged coaxially within one another and rotatable relative to one another about a common axis. Two of the three gear elements have magnetic pole pairs distributed over their circumference. The gear element with fewer magnetic pole pairs is referred to below as the low-pole gear element, and the gear element with more magnetic pole pairs is referred to as the high-pole gear element.

[0016] A third gear element, referred to here as the modulator, has magnetic conductors that lead to the magnetic poles of the low-pole and high-pole gear elements, i.e. the magnetic conductors of the modulator conduct magnetic field lines from the magnetic poles of the low-pole gear element to the magnetic poles of the high-pole gear element and vice versa in such a way that torques are transmitted by magnetic forces between the gear elements when the gear elements are rotated against each other from an equilibrium position.

[0017] The magnetic poles of the low-pole and high-pole gear elements and pole pieces of the modulator extend in a direction parallel to the axis and additionally exhibit a circumferential offset along their axially parallel extension. Specifically, the magnetic poles and pole pieces are helical. The circumferential offset of the magnetic poles and pole pieces over the axial extension is an angle between the axial ends of the magnetic poles and the pole pieces in the circumferential direction. The circumferential offset of the magnetic poles and pole pieces over the axial extension can also be referred to as "skew."It is sufficient if the magnetic poles of the low-pole and high-pole gear element or the magnetic poles of the low-pole or high-pole gear element and the pole shoes of the modulator are offset; the magnetic poles of the low-pole or high-pole gear element or the pole shoes of the modulator can run straight and parallel to the axis without offset in the circumferential direction.

[0018] The “pole shoes” of the modulator or the magnetic conductors of the modulator are surfaces, in particular end faces of the magnetic conductors, which face the magnetic poles of the low-pole and high-pole gear elements and at which magnetic field lines emerging from or entering the magnetic poles of the low-pole and high-pole gear elements enter or exit the magnetic conductors.

[0019] As described above, at least two of the three gear elements of the magnetic gear according to the invention have a set, i.e., the magnetic poles and pole shoes of at least two of the three gear elements extend not only in the axial direction, but also have an offset in the circumferential direction between their axial ends along their axial extent, with this offset being different for all three gear elements. According to the invention, the following relationships apply to a difference in the offset in the circumferential direction between the gear elements:

[0020] The difference in the offset of the magnetic poles of the low-pole gear element and the magnetic poles of the high-pole gear element in the circumferential direction along their axial extent is 360° divided by an integer multiple of the number of magnetic pole pairs of the high-pole gear element and the number of magnetic pole pairs of the low-pole gear element. The gear element with fewer magnetic poles is referred to as the low-pole gear element, and the gear element with more magnetic poles is referred to as the high-pole gear element. Choosing a smallest common multiple of the number of magnetic pole pairs of the high-pole gear element and the number of magnetic pole pairs of the low-pole gear element results in the smallest possible entanglement, i.e., the smallest difference in the offset of the magnetic poles of the low-pole gear element and the magnetic poles of the high-pole gear element in the circumferential direction along their axial extent.If you choose a value larger than the lowest common multiple, the entanglement increases gradually accordingly.

[0021] According to the invention, the difference in the offset of the pole shoes of the modulator and the magnetic poles of the high-pole gear element in the circumferential direction on their axial extent is as large as the difference in the offset of the magnetic poles of the low-pole gear element and the magnetic poles of the high-pole gear element in the circumferential direction on their axial extent specified in the previous paragraph divided by the ratio of the number of magnetic pole pairs of the high-pole gear element, which has more magnetic poles, and the number of magnetic pole pairs of the low-pole gear element, which has fewer magnetic poles, plus 1. The "1" is added to the ratio of the number of magnetic pole pairs in the denominator of the fraction.

[0022] Finally, the difference in offset between the pole pieces of the modulator and the magnetic poles of the low-pole gear element in the circumferential direction on their axial extent is as large as the difference in offset of the magnetic poles of the low-pole gear element and the magnetic poles of the high-pole gear element in the circumferential direction on their axial extent less the difference in offset between the magnetic poles of the high-pole gear element and the pole pieces of the modulator in the circumferential direction on their axial extent.

[0023] The offsets of the magnetic poles and the pole shoes of the three gear elements of the magnetic gear according to the invention or the differences between these offsets can be given using the following mathematical formulas: ΔφIA=360°gV(ppzIM;ppzAM) ΔφMA=ΔφIA(ppzAMppzIM)+1 ΔφMI=ΔφIA−ΔφAM

[0024] This is φ is the offset of the magnetic poles of the low-pole and high-pole gear elements and of the pole pieces of the modulator in the circumferential direction on their axial extension, Δφ is the difference in offset between the magnetic poles of the low-pole and high-pole gear elements and the pole pieces of the modulator in the circumferential direction on their axial extent, where the indices I for the low-pole gear element, which has fewer magnetic poles, A for the high-pole gear element, which has more magnetic poles, and M stands for the modulator with the magnetic conductors and the pole pieces, gV is an integer multiple of the pole pair numbers of the low-pole and high-pole gear elements, ppzIM is the number of pole pairs of the low-pole gear element, which has fewer magnetic poles and ppzAM is the number of pole pairs of the high-pole gear element, which has more magnetic poles.

[0025] The subordinate claim 2 is directed to a transition from the magnetic gear of claim 1, which has a continuous offset, i.e., whose magnetic poles and pole shoes are, in particular, helical, to a magnetic gear with a layered structure of its gear elements with a stepped offset of the magnetic poles and pole shoes in the circumferential direction from layer to layer. This means that the magnetic poles and pole shoes of the gear elements are offset in the circumferential direction from layer to layer. The offset of the magnetic poles and pole shoes in the circumferential direction, from a virtual, zeroth layer to a final layer, is equal to the offset of the axial ends of the magnetic poles and pole shoes in the magnetic gear of claim 1 with the continuous offset. The offset of the magnetic poles and pole shoes is distributed evenly across the layers.

[0026] The formula applies: φk=φkontkgates⋅[k−1], where k is the number of a layer, k ges the number of layers φ k the offset of the magnetic poles of layer k with respect to the first layer or to a layer 1 and φ kont the above-explained twisting of the magnetic poles and pole shoes of the magnetic gear with continuous twisting.

[0027] The layers can be distributed axially in any way or interchanged with each other. In this case, instead of a last and a first layer, there is a layer with the largest offset and a layer with the smallest offset, as well as all intermediate layers at essentially any position on the gear elements in the axial direction.

[0028] Claim 3 defines the magnetic gear with the layered structure and the stepped offset of the magnetic poles and pole shoes from layer to layer as a claim dependent on claim 1.

[0029] The dependent claims relate to advantageous embodiments and further developments of the invention.

[0030] Due to the ease of manufacture, in a preferred embodiment of the invention the magnetic poles of the low-pole or high-pole gear element or the pole shoes of the modulator extend without twisting, i.e. not helically but straight axially parallel without offset in the circumferential direction.

[0031] If the set, the magnetic poles or the pole shoes of one of the three gear elements, i.e. their offset in the circumferential direction over their axial extent, is increased or reduced, the set, i.e. the offset of the magnetic poles and the pole shoes of the two other gear elements in the circumferential direction over their axial extent, increases accordingly.

[0032] The invention also encompasses deviations in the offsets of the magnetic poles and the pole pieces in the circumferential direction over their axial extent from the above specifications of up to 10%, up to 20%, or up to 30%, or up to approximately 1°, up to approximately 2°, or up to approximately 3°, for example, due to manufacturing tolerances or for reasons of easier manufacturing or other manufacturing reasons, or for other reasons. For example, commercially available permanent magnets have a tolerance for their offset of, for example, ±1°.

[0033] Instead of permanent magnets, the low-pole and / or high-pole magnetic gears can also have electromagnets.

[0034] All features mentioned in the description and / or illustrated in the drawings may be implemented individually or in any combination in embodiments of the invention. Embodiments of the invention that include only a portion of the features of a claim, including the independent claim, are possible.

[0035] The invention is explained in more detail below with reference to two exemplary embodiments illustrated in the drawings. They show: Fig. 1 is a perspective view of a first embodiment of a magnetic gear according to the invention; Fig. 2 an exploded view of the magnetic gear from Fig. 1; Fig. 3 a front view of the magnetic gear from Fig. 1; Fig. 4 magnets of a high-pole gear element of the magnetic gear made of Fig. 1; Fig. 5 Magnets of a multi-pole gear element of a second embodiment of a magnetic gear according to the invention; Fig. 6 magnetic conductors of a modulator of the second embodiment of a magnetic gear according to the invention; and Fig. 7 Magnets of a low-pole gear element of the second embodiment of a magnetic gear according to the invention.

[0036] In principle, identical parts in the figures are provided with identical reference numbers.

[0037] The drawing is intended as a schematic and simplified representation for understanding and explaining the invention. The figures are drawn to different scales.

[0038] The Fig. 1 to 3, the first embodiment of a magnetic gear 1 according to the invention, which is shown in a highly simplified manner, has three gear elements 2, 3, 4 arranged coaxially one inside the other and which are rotatable relative to one another about their axes as a common axis of rotation 5.

[0039] A first gear element 2, referred to here as the low-pole gear element - in the exemplary embodiment, the inner gear element - has a cylindrical shaft 6 rotatable about its axis, on the outer circumference of which an even number of cylindrical shell-shaped permanent magnets 7 are arranged. The permanent magnets 7 extend axially over a length of the shaft 6 and are helical in such a way that their axial ends have an offset φ l in a circumferential direction to each other. The helical shape of the permanent magnets 7 of the low-pole gear element 2 of the magnetic gear 1 according to the invention is shown in the exploded view of the Fig. 2. The permanent magnets 7 are alternately oriented in opposite directions such that a magnetic north pole n and a magnetic south pole s are alternately located on an outer circumference of the low-pole gear element 2. The shaft 6 is made of a magnetically conductive material and forms a magnetic yoke. In the exemplary embodiment, the low-pole gear element 2 has six permanent magnets 7, i.e., three magnetic pole pairs n, s, on its outer circumference. The low-pole gear element 2 can also have more or fewer permanent magnets 7 or magnetic pole pairs n, s.

[0040] A high-pole gear element 3—outer in the exemplary embodiment—is cylindrical in shape and coaxially encloses the low-pole gear element 2 with an annular intermediate space. The high-pole gear element 3 has a tube 8, on the inner circumference of which an even number of permanent magnets 9 are arranged, the inner surfaces of which alternately form magnetic north poles N and magnetic south poles S. The tube 9 is made of a magnetically conductive material and forms a magnetic yoke. The high-pole gear element 3 has a larger number of permanent magnets 9 than the low-pole gear element 2 and, in the exemplary embodiment, is arranged on the outside, i.e., coaxially enclosing the low-pole gear element 2. Versions of the magnetic gear 1 are also possible in which the low-pole gear element 2 is on the outside and the high-pole gear element 3 is on the inside.In the illustrated embodiment, the multi-pole gear element 3 has 22 permanent magnets 9, which have eleven magnetic pole pairs N, S on its inner circumference. Here, too, the number may vary.

[0041] The permanent magnets 9 of the multi-pole gear element 3 extend axially over a length of the multi-pole gear element 3 and are also helical such that axial ends of the permanent magnets 9 have an offset φ A in the circumferential direction to each other. In the exemplary embodiment, the helical permanent magnets 7, 9 of the inner and outer gear elements 2, 3 have opposite pitches. Fig. Figure 4 shows a view of the permanent magnets 9 of the multi-pole gear element 3 without the surrounding tube 9, which forms the magnetic yoke. Here, the helical shape of the permanent magnets 9 of the multi-pole gear element 3 is visible.

[0042] In the annular space between the low-pole and the high-pole gear element 2, 3, a third gear element, also in the form of a cylindrical tube, is arranged coaxially. The third gear element has strip-shaped magnetic conductors 10 which, in the exemplary embodiment, run straight and parallel to the axis ( Fig. 2). The third gear element with the magnetic conductors 10 is referred to here as the modulator 4 of the magnetic gear 1 according to the invention. However, embodiments of the magnetic gear 1 according to the invention with helical instead of straight magnetic conductors 10 are also possible (not shown). Inner circumferential surfaces of the magnetic conductors 7 of the modulator 4 form pole shoes 11—inner in the exemplary embodiment—which face the magnetic poles n, s on the outer circumference of the low-pole gear element 2. Outer circumferential surfaces of the magnetic conductors 7 of the modulator 4 form pole shoes 12—outer in the exemplary embodiment—which face the magnetic poles N, S on the inner circumference of the high-pole gear element 3.Pole shoes 11, 12 are the surfaces of the magnetic conductors 10 of the modulator 4 at which magnetic field lines of the magnetic poles n, s, N, S of the permanent magnets 7, 9 of the low-pole and high-pole gear elements 2, 3 enter or exit the magnetic conductors 10. In the exemplary embodiment, these are the inner and outer circumferential surfaces of the magnetic conductors 10.

[0043] In the circumferential direction, the magnetic conductors 10 of the modulator 4 are magnetically isolated from each other. For this purpose, the magnetic conductors 10 are connected to each other by a carrier, which is not shown in the drawing for clarity. The carrier connects the magnetic conductors 10 to the tubular modulator 4. The carrier is magnetically neutral; ideally, it does not influence the magnetic flux between the magnetic poles n, s, N, S of the low-pole gear element 2 and the high-pole gear element 3.

[0044] The magnetic conductors 10 of the modulator 4 conduct magnetic field lines back and forth between the magnetic poles n, s of the low-pole gear element 2 and the magnetic poles N, S of the modulator 4. In the exemplary embodiment, the modulator 4 has fourteen magnetic conductors 10 and thus fourteen pole pieces 11 on the inner circumference and fourteen pole pieces 12 on the outer circumference. Here, too, the modulator 4 can have a different number of magnetic conductors 10 and thus a different number of pole pieces 11, 12 than fourteen.

[0045] The three gear elements 2, 3, 4 of the magnetic gear 1 can rotate relative to each other about their common axes as rotation axis 5.

[0046] Here, the low-pole gear element 2 is the gear element 2 that has fewer magnetic poles n, s, and the high-pole gear element 3 is the gear element 3 that has more magnetic poles N, S. Conversely to the exemplary embodiment, the low-pole gear element 2 with the smaller number of magnetic poles n, s can be arranged on the outside and the high-pole gear element 3 with the larger number of magnetic poles N, S can be arranged on the inside (not shown).

[0047] A uniform rotary drive of one of the three gear elements 2, 3, 4 of the magnetic gear 1 with another of the three gear elements 2, 3, 4 held in a rotationally fixed manner causes a rotation of a third of the three gear elements 2, 3, 4, which is used as the output of the magnetic gear 1, whereby this rotation is not uniform but has a ripple, i.e. the output gear element 2, 3, 4 accelerates and decelerates alternately by an average value of its rotation (so-called "ripples").

[0048] In order to keep the torque ripple of the output gear element 2, 3, 4 small, the axial ends of the permanent magnets 7, 8 of the low-pole and high-pole gear element 2, 3 of the magnetic gear 1 according to the invention have a difference in the offset Δφ IAin the circumferential direction, which is 360° divided by an integer multiple of the number of magnetic pole pairs n, s of the low-pole gear element 2 and the number of magnetic pole pairs N, S of the high-pole gear element 3. If a lowest common multiple is chosen, the offset Δφ is IA is the smallest. In the embodiment with three magnetic pole pairs n, s of the low-pole gear element 2 and eleven magnetic pole pairs N, S of the high-pole gear element 3, the lowest common multiple is 33 and the difference of the offset Δφ IA of the axial ends of the permanent magnets 7, 9 and the magnetic poles n, s, N, S of the low-pole and high-pole gear elements 2, 3 in the circumferential direction is 10.9° or an integer multiple thereof. This is the offset Δφ IAin the circumferential direction of the axial ends of the permanent magnets 7, 9 and the magnetic poles n, s, N, S of the low-pole and high-pole gear elements 2, 3 at one axial end of the gear elements 2, 3, if the permanent magnets 7, 9 and the magnetic poles n, s, N, S at the other axial end of the gear elements 2, 3 have no offset Δφ IA in the circumferential direction to each other.

[0049] A difference of the offset Δφ MA between the axial ends of the magnetic conductors 10 and the pole pieces 11, 12 of the modulator 4 and the axial ends of the permanent magnets 9 and the magnetic poles N, S of the multi-pole gear element 3 in the circumferential direction is as large as the difference of the offset Δφ specified in the previous paragraph IAof the axial ends of the permanent magnets 7, 9 and the magnetic poles n, s, N, S of the low-pole and high-pole gear elements 2, 3 in the circumferential direction divided by the quotient of the number of magnetic pole pairs N, S of the high-pole gear element 3 and the number of magnetic pole pairs n, s of the low-pole gear element 2 plus 1, with the "1" being added to the quotient in the denominator of the fraction. In the exemplary embodiment with 22 magnetic poles N; S of the high-pole gear element 3 and six magnetic poles n, s of the low-pole gear element 2, the quotient is 3.67, the denominator of the fraction is 4.67, and the difference in the offset is Δφ MA between the axial ends of the magnetic conductors 10 and the pole pieces 11, 12 of the modulator 4 and the axial ends of the permanent magnets 9 and the magnetic poles N, S of the multi-pole gear element 3 in the circumferential direction 2.33° or an integer multiple thereof.

[0050] A difference of the offset Δφ MIbetween the axial ends of the magnetic conductors 10 and the pole pieces 11, 12 of the modulator 4 and the axial ends of the permanent magnets 7 and the magnetic poles n, s of the low-pole gear element 2 in the circumferential direction is as large as the difference of the offset Δφ IA the axial ends of the permanent magnets 7, 9 and the magnetic poles n, s, N, S of the low-pole and high-pole gear elements 2, 3 in the circumferential direction less the difference in the offset Δφ AM between the axial ends of the permanent magnets 9 and the magnetic poles N, S of the multi-pole gear element 3 and the axial ends of the magnetic conductors 10 and the pole pieces 11, 12 of the modulator 4 in the circumferential direction

[0051] The offsets of the magnetic poles and the pole shoes of the three gear elements of the magnetic gear according to the invention or the differences between these offsets can be given using the following mathematical formulas: ΔφIA=360°gV(ppz IM;ppzAM) ΔφMA=φIA(ppzAMppzIM)+1 ΔφMI=ΔφIA−ΔφAM

[0052] This is φ is the offset of the magnetic poles of the low-pole and high-pole gear elements and of the pole pieces of the modulator, Δφ is the difference in the offset between the magnetic poles of the low-pole and high-pole gear element and the pole pieces of the modulator, where the indices I for the low-pole gear element, which has fewer magnetic poles, A for the high-pole gear element, which has more magnetic poles, and M stands for the modulator with the magnetic conductors and the pole pieces, gV is an integer multiple of the pole pair numbers of the low-pole and high-pole gear elements, ppzIM is the number of pole pairs of the low-pole gear element, which has fewer magnetic poles and ppzAM is the number of pole pairs of the high-pole gear element, which has more magnetic poles.

[0053] If—as in the exemplary embodiment—the magnetic conductors 10 and the pole pieces 11, 12 of the modulator 4 are straight and run axially parallel without a gradient, the axial ends of the permanent magnets 9 and the magnetic poles N, S of the high-pole gear element 3 have an offset of 2.33° or an integer multiple thereof in the circumferential direction. The axial ends of the permanent magnets 7 and the magnetic poles n, s of the low-pole gear element 2 have an offset of 10.9° - 2.33° = 8.57° or an integer multiple thereof in the opposite circumferential direction. The permanent magnets 7, 9 and the magnetic poles n, s, N, S of the low-pole and high-pole gear elements 2, 3 also exhibit this offset over their axial extent with respect to the magnetic conductors 10 and the pole shoes 11, 12 of the modulator 4, even if the magnetic conductors 10 and the pole shoes 11, 12 of the modulator 4 have a gradient and run helically.In absolute terms, the offset of the permanent magnets 7, 9 and the magnetic poles n, s, N, S of the low-pole and high-pole gear elements 2, 3 increases or decreases in the case of opposite pitches on their axial extent if the magnetic conductors 10 and the pole shoes 11, 12 of the modulator 4 have a pitch and run helically.

[0054] If the pitch of the permanent magnets 7, 9 of the low-pole or high-pole gear element 2, 3 is increased or decreased, the pitch of the permanent magnets 9, 7 of the high-pole or low-pole gear element 3, 2 increases or decreases accordingly, and the magnetic conductors 10 of the modulator 4 become helical. The magnetic gear 1 according to the invention can be formed with helical permanent magnets 7, 9 and helical magnetic conductors 10 of all three gear elements 2, 3, 4 or with straight permanent magnets 7, 9 of either the low-pole or high-pole gear element 2, 3 and helical permanent magnets 9, 7 of the high-pole or low-pole gear element 3, 2 and helical magnetic conductors 10 of the modulator 4 (not shown).

[0055] With the magnetic gear 1 according to the invention explained above, a high torque transmission with low torque ripple of the output gear element 2, 3, 4 is achieved with a uniform rotary drive of one of the three gear elements 2, 3, 4.

[0056] For a ratio i of the magnetic gear 1 with input of the low-pole gear element 2, output on the high-pole gear element 3 and non-rotatable modulator 4, the following applies: i=ppzAMppzIM, In the example, i=-3.66.

[0057] With drive of the low-pole gear element 2, output on the modulator 4 and non-rotatable high-pole gear element 3: i=ppzAMppzIM+1, In the example, i=4.66.

[0058] The Fig. 5 to 7 show permanent magnets 7, 9 of a low-pole and a high-pole gear element 2, 3 and magnetic conductors 10 of a modulator 4 of a second embodiment of a magnetic gear 1 according to the invention. The front view of both embodiments is identical ( Fig. 3). In the second embodiment of the magnetic gear 1 according to the invention, the permanent magnets 7, 9 and magnetic poles n, s, N, S are not helical and do not have a continuous twist, but the magnetic gear 1 is arranged along its axial length in k ges Layers that are rotated relative to each other around the axis and rotation axis 5. Within each gear element 2, 3, 4, the layers are rotationally fixed to each other. Here, k gesis the number of layers, and k is the number of the respective layer. All layers are equally wide in the axial direction of the magnetic gear 1. The second embodiment is, so to speak, a transition from the first embodiment with the continuous offset to a stepped offset of the permanent magnets 7, 9 and the magnetic poles n, s, N, S in the circumferential direction from layer to layer.

[0059] The low-pole and high-pole gear elements 2, 3 have the same number of layers k gesIn the circumferential direction, the low-pole gear element 2 has fewer permanent magnets 7 and magnetic poles n, s than the high-pole gear element 3. In the axial direction, the permanent magnets 7, 10 and the magnetic poles n, s, N, S are divided; the two gear elements 2, 3 have as many permanent magnets 7, 10 and magnetic poles n, s, N, S in the axial direction as the magnetic gear 1 and the gear elements 2, 3 have layers. The permanent magnets 7, 10 and the magnetic poles n, s, N, S are offset from one another in the circumferential direction from layer to layer.

[0060] The offset of the permanent magnets 7, 10 and the magnetic poles n, s, N, S of the low-pole and high-pole gear elements 2, 3 in the circumferential direction is from an imaginary zeroth layer k0 to a last layer k gesas large as the offset of the axial ends of the permanent magnets 7, 10 and the magnetic poles n, s, N, S in the first embodiment of the invention. The offset of the permanent magnets 7, 10 and the magnetic poles n, s, N, S is distributed evenly from layer to layer in the circumferential direction.

[0061] The offset of the permanent magnets 7, 10 and the magnetic poles n, s, N, S of the low-pole and high-pole gear elements 2, 3 in the circumferential direction for the k-th layer compared to the first layer is: φk=φkontkgates⋅[k−1]

[0062] The offset of the permanent magnets 7, 10 and the magnetic poles n, s, N, S of the low-pole and high-pole gear elements 2, 3 in the circumferential direction from a first layer k=1 to a last layer k ges is therefore: φkges=φkontkges⋅[kges−1] In the example with eight layers (k ges=8) is the offset of the permanent magnets 7, 10 and the magnetic poles n, s, N, S of the low-pole and high-pole gear elements 2, 3 between the first and the last (eighth) layer of the magnetic gear 1: φkges=φkontkges⋅[kges−1]=φkont8⋅[8−1]=φkont⋅78 The offset of the permanent magnets 7, 10 and the magnetic poles n, s, N, S in the circumferential direction is evenly distributed from layer to layer and the low-pole gear element 2, the high-pole gear element 3 and, if applicable, the modulator 4 have the same number of layers.

[0063] The layers do not have to be arranged in the order of their numbers but can be swapped arbitrarily. That is, the layer with the offset φ kdoes not have to be located at position k, but can be arranged as the first, last, or any layer in between. However, the layers numbered k of the low-pole and high-pole gear elements 2 and 3 must be arranged at the same position.

[0064] The modulator 4 in the second embodiment is designed the same as in the first embodiment because its magnetic conductors 10 and pole pieces 11, 12 run straight and axially parallel. However, as in the first embodiment, it is also possible to divide the magnetic conductors 10 and pole pieces into layers and arrange them with an offset in the circumferential direction from layer to layer (not shown). In this case, the offset of the permanent magnets 7, 9 and the magnetic poles n, s, N, S of the low-pole and high-pole gear elements 2, 3 increases or decreases accordingly. In versions of the second embodiment of the magnetic gear 1 according to the invention, the permanent magnets 7, 9 and magnetic poles n, s, N, S of the low-pole or high-pole gear elements 2, 3 can run straight through, axially parallel (not shown).

[0065] To explain the second embodiment of the magnetic gear 1 according to the invention, reference is made to the explanations of the first embodiment.

[0066] Designs of the magnetic gear 1 according to the invention with electromagnets instead of the permanent magnets 7, 9 of the low-pole and / or the high-pole gear element 2, 3 are also possible.

Claims

[1] Magnetic gear with three coaxially arranged, mutually rotatable gear elements (2, 3, 4), of which a low-pole gear element (2) has magnetic pole pairs (n, s) distributed over a circumference, a high-pole gear element (3) has magnetic pole pairs (N, S) distributed over a circumference, and a third gear element forms a modulator (4) which has magnetic conductors (10) leading from the magnetic poles (n, s) of the low-pole gear element (2) to the magnetic poles (N, S) of the high-pole gear element (3), wherein the magnetic poles (n, s) of the low-pole gear element (2), the magnetic poles (N, S) of the high-pole gear element (3) and pole shoes (11, 12) of the magnetic conductors (10) of the modulator (4) extend in an axially parallel direction and the magnetic poles (n, s, N, S) and / or pole shoes (11, 12) of at least two of the three gear elements (2, 3,4) have an offset (φ) in a circumferential direction along their extension in the axially parallel direction, characterized by that a difference (Δφ IA ) of the offset (φ) between the magnetic poles (n, s) of the low-pole gear element (2) and the magnetic poles (N, S) of the high-pole gear element (3) in the circumferential direction on the extension in the axis-parallel direction 360° divided by an integer multiple of the number (ppzlM) of the magnetic pole pairs (n, s) of the low-pole gear element (2) and the number (ppzAM) of the magnetic pole pairs (N, S) of the high-pole gear element (3) is that a difference (Δφ MA ) of the offset between the pole shoes (11, 12) of the modulator (3) and the magnetic poles (N, S) of the multi-pole gear element (2) in the circumferential direction on their extension in the axis-parallel direction equal to the difference (Δφ IA) of the offset between the magnetic poles (n, s) of the low-pole gear element (2) and the magnetic poles (N, S) of the high-pole gear element (3) divided by the ratio of the number (ppzAM) of the magnetic pole pairs (N, S) of the high-pole gear element (3) and the number (ppzlM) of the magnetic pole pairs (n, s) of the low-pole gear element (2) plus 1, and that a difference in the offset (Δφ MI ) between the pole shoes (11, 12) of the modulator (4) and the magnetic poles (n, s) of the low-pole gear element (2) in the circumferential direction on their extension in the axis-parallel direction of the difference of the offset (Δφ IA ) between the magnetic poles (n, s) of the low-pole gear element (2) and the magnetic poles (N, S) of the high-pole gear element (3) in the circumferential direction on their extension in the axis-parallel direction less the difference in the offset (Δφ AM) between the magnetic poles (N, S) of the multi-pole gear element (3) and the pole shoes (11, 12) of the modulator (4) in the circumferential direction on their extension in the axis-parallel direction. [2] Magnetic gear with three coaxially arranged, counter-rotatable gear elements (2, 3, 4), of which a low-pole gear element (2) has magnetic pole pairs (n, s) distributed over a circumference and arranged axially parallel next to one another, a high-pole gear element (3) has magnetic pole pairs (N, S) distributed over a circumference and arranged axially parallel next to one another, and a third gear element, which forms a modulator (4), has magnetic conductors (10) leading from the magnetic poles (n, s) of the low-pole gear element (2) to the magnetic poles (N, S) of the high-pole gear element (3), wherein adjacently arranged magnetic poles (n, s) of the low-pole gear element (2) and adjacently arranged magnetic poles (N, S) of the high-pole gear element (3) have an offset in the circumferential direction with respect to the pole shoes (11, 12) of the modulator (4), characterized bythat the offset of the adjacently arranged magnetic poles (n, s) of the low-pole gear element (2) in the circumferential direction with respect to the pole shoes (11, 12) of the modulator (4) is opposite to the offset of the adjacently arranged magnetic poles (N, S) of the high-pole gear element (3) in the circumferential direction with respect to the pole shoes (11, 12) of the modulator (4), that an offset of the adjacently arranged magnetic poles (n, s) of the low-pole gear element (2) in the circumferential direction with respect to the adjacently arranged magnetic poles (N, S) of the high-pole gear element (3) is 360° divided by an integer multiple of the number of magnetic pole pairs (n, s) of the low-pole gear element (2) distributed over the circumference and the number of magnetic pole pairs (N, S) of the high-pole gear element (3) distributed over the circumference and divided by the number of adjacent magnetic poles (n, s, N,S) of the low-pole gear element (2) or the high-pole gear element (3) and that the offset of the adjacently arranged pole shoes (11, 12) of the modulator (4) with respect to the magnetic poles (N, S) of the high-pole gear element (3) in the circumferential direction is 360° divided by the integer multiple of the number of magnetic pole pairs (n, s) of the low-pole gear element (2) distributed over the circumference and the number of magnetic pole pairs (N, S) of the high-pole gear element (3) distributed over the circumference and divided by the number of magnetic poles (n, s, N, S) of the low-pole gear element (2) or the high-pole gear element (3) arranged next to one another and divided by the quotient of the number of magnetic pole pairs (N, S) of the high-pole gear element (3) distributed over the circumference and the number of magnetic pole pairs (n, s) of the low-pole gear element (2) plus 1., [3] Magnetic gear according to claim 1 or 2, characterized by that the offset of the magnetic poles (n, s, N, S) and the pole shoes (11, 12) of the gear elements (2, 3, 4) in the circumferential direction on their axial extent is carried out stepwise in layers, wherein the offset of the magnetic poles (n, s, N, S) and the pole shoes (11, 12) of the gear elements (2, 3, 4) in the circumferential direction between a first layer (k1) and a last layer (k ges ) of a transmission element (2, 3, 4) to the offset (φ) specified in claim 1 divided by the number of layers (k ges ) and multiplied by the number of layers (k ges ) minus 1 and the offset of the magnetic poles (n, s, N, S) and the pole shoes (11, 12) in the circumferential direction between the layers (k) is constant. [4] Magnetic gear according to claim 1, 2 or 3, characterized bythat either the magnetic poles (n, s) of the low-pole gear element (2) or the magnetic poles (N, S) of the high-pole gear element (3) or the pole shoes (11, 12) of the modulator (4) extend exclusively axially parallel without offset in the circumferential direction. [5] Magnetic gear according to one or more of claims 1 to 4, characterized by that the offset of the magnetic poles (n, s, N, S) of the low-pole gear element (2) and / or the high-pole gear element (3) and / or the pole shoes (11, 12) of the modulator (4) in the circumferential direction has a deviation of up to 10%, up to 20% or up to 30% or a deviation of up to 1°, up to 2° or up to 3°. [6] Magnetic gear according to one or more of the preceding claims 1 to 5, characterized by that the magnetic poles (n, s, N, S) of the low-pole gear element (2) and / or the high-pole gear element (3) and / or the pole shoes (11, 12) of the modulator (4) run helically. [7] Magnetic gear according to one or more of the preceding claims, characterized by that the low-pole gear element (2) and / or the high-pole gear element (4) has permanent magnets (n, s, N, S) or electromagnets.

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