Magnetgear

Abstract

This magnetic drive comprises a magnetic drive element (5) in which each of a multipole mechanism (4), a less-pole mechanism (2), and a pole piece (3) shares the function of one of a stator, a first rotor, and a second rotor. The positional relation of the magnetic poles is such that at least one of the multipole mechanism (4), the less-pole mechanism (2), and the pole piece (3) exhibits a phase difference (θ) between adjacent sections (5a, 5b, 5c) among a plurality of sections divided along the axial direction. At least one of the greatest common divisors of the number of poles of the multipole mechanism (4) and the pole piece (3) and the greatest common divisor of the number of poles of the less-pole mechanism (2) and the pole piece (3) is 1 or 2.

Description

Technical area

[0001] The present invention relates to a magnetic gear. State of the art

[0002] In a typical rotating electric machine configured with permanent magnets and soft magnetic materials, as the speed increases, the induced voltage decreases, and the input voltage that can be used for torque output decreases. Therefore, a decrease in torque and a decrease in efficiency occur due to an increase in iron loss. To achieve desired output and efficiency characteristics, a drive unit is typically configured by combining a rotating electric machine and a gearbox so that the speed of the rotating electric machine falls within a suitable range.

[0003] Mechanical gears, which have a meshing structure of mechanical teeth, are widely used as transmission gears. Recently, however, magnetic gears have been increasingly used, enabling contactless power transmission without the use of mechanical gears. The magnetic gear from the old system has a configuration in which the teeth of a mechanical gear are simply replaced by permanent magnets. However, since magnetic gears enable contactless acceleration and deceleration using the attractive and repulsive forces of magnetic force, vibrations and disturbances are minimal, and maintainability is expected to improve.

[0004] However, when transmitting torque using permanent magnets, the following applies: Since only the magnets facing each other contribute to torque transmission, the torque is small compared to a mechanical transmission. In contrast, a new type of magnetic transmission, called a flux-modulated magnetic transmission, is used. This type of transmission is configured to increase the value of the magnetic flux contributing to torque transmission, in a structure designed to increase torque.

[0005] The flux-modulated type magnetic gear is constituted by a multi-pole mechanism and a few-pole mechanism in which the permanent magnets are concentrically arranged so that their polarities are alternately reversed and their arrangement surfaces face each other with a gap therebetween, and it is constituted by a plurality of magnetic pole pieces made of a soft magnetic material or the like, called pole pieces, which are arranged at a uniform pitch or interval in the gap.

[0006] Although the flux modulated type magnetic gear can improve the transmission torque, since the soft magnetic material is periodically arranged at a position extremely close to a permanent magnet, periodic vibrations are generated by the electromagnetic excitation force or cogging torque, by the same principle as the rotating electric machine.

[0007] Therefore, there are concerns about electromagnetic interference due to vibrations of the stator and frame of the rotating electrical machine, adverse effects on the load at a connection target due to vibrations transmitted to the output shaft, and deterioration of controllability. On the other hand, a structure has been proposed in which permanent magnets arranged in a rotor of a magnetic gear are continuously chamfered in the axial direction, and the cogging torque generated in each of the cross sections in the axial direction of the magnetic gear is canceled due to the phase relationship (see, for example, Patent Document 1). State of the art documentPatent document

[0008] Patent Document 1: International Publication of an Unexamined Application WO2015 / 053005 A1 (paragraphs 0020 to 0033, Fig. 1 to Fig. 4). Summary of the inventionProblems to be solved by the invention

[0009] However, the structure in which the permanent magnets are continuously tapered in the axial direction has the problem of increasing manufacturing costs, as a dedicated manufacturing facility is required to manufacture the permanent magnets, which must have a special shape, and to combine the permanent magnets with the rotor core. On the other hand, in a case where the cogging torque is reduced without using the tapered structure, a method is considered in which the number of poles of the magnetic gear is such that the order of the cogging torque increases.

[0010] However, it is necessary to increase the lowest common multiple of the number of pole pieces of the magnetic gear and the number of permanent magnets of the multi-pole mechanism while maintaining the practical gear ratio, and in such a configuration, there is a problem that electromagnetic noise due to the electromagnetic excitation force increases, which is due to a decrease in order.

[0011] The present invention has been conceived to solve the problems described above, and it is an object of the present invention to obtain a magnetic gear of the flux modulated type which achieves both a reduction in the cogging torque and a reduction in the electromagnetic excitation force without increasing the manufacturing cost. Ways to solve the problem

[0012] The magnetic transmission disclosed in the present invention comprises: a magnetic transmission element configured such that each of a multi-pole mechanism, a few-pole mechanism, and a pole piece shares a function of any one of a stator, a first rotor, and a second rotor, wherein the multi-pole mechanism has magnetic poles of first numbers arranged along the circumferential direction with permanent magnets, the few-pole mechanism has magnetic poles of second numbers less than those of the first numbers and arranged along the circumferential direction with permanent magnets, and the pole piece has magnetic poles of third numbers arranged along the circumferential direction with soft magnetic material through magnetic gaps with respect to each of the magnetic poles of the multi-pole mechanism and the few-pole mechanism; a first shaft for transmitting torque between the first rotor and the outside;and a second shaft for transmitting torque between the second rotor and the outside. In the magnetic gear element, between adjacent sections among a plurality of sections divided along an axial direction, the positional relationship of the magnetic poles among the multi-pole mechanism, the few-pole mechanism, and the pole piece is different, so that at least one of the multi-pole mechanism, the few-pole mechanism, and the pole piece has a phase difference, and at least one of a greatest common factor of the first and third pole numbers and a greatest common factor of the second and third pole numbers is 1 or 2. Advantageous effect of the invention

[0013] With the magnetic gear disclosed according to the present invention, it is possible to obtain a flux-modulated type magnetic gear that achieves both a reduction in cogging torque and a reduction in electromagnetic excitation force without increasing the manufacturing cost. Brief description of the drawings Fig. 1 is a cross-sectional view taken along a rotation axis showing a configuration of a magnetic gear according to Embodiment 1. Fig. 2A and Fig. 2B are cross-sectional views perpendicular to the rotation axis of a first portion and a second portion, respectively, of a magnetic gear element having a two-stage structure constituting the magnetic gear according to Embodiment 1. Fig. 3A and Fig. 3B are diagrams showing relations of an x-component of an electromagnetic excitation force and a y-component of the electromagnetic excitation force, respectively, with respect to a rotation angle as reference to a multi-pole mechanism in a magnetic gear element of the magnetic gear according to Embodiment 1. Fig. 4 is a vector diagram of the electromagnetic excitation force generated in multi-pole mechanisms in the first section and the second section of the magnetic transmission according to Embodiment 1. Fig. 5A and Fig. 5B are a cross-sectional view perpendicular to the rotation axis in the magnetic gear in the second section and a vector diagram of the electromagnetic excitation force generated in the multi-pole mechanism according to a variation example of Embodiment 1, respectively. Fig. 6A and Fig. 6B each show a relationship between a circumferential position of the multi-pole mechanism of the magnetic gear and the first-order component of the electromagnetic excitation force, and a relationship between a phase difference of the two sections and an amplitude of the first-order component of the electromagnetic excitation force of an entire magnetic gear element according to the variation example of Embodiment 1. Fig. 7 is a cross-sectional view along the rotation axis showing a configuration of a magnetic gear according to Embodiment 2. Fig. 8 is a cross-sectional view perpendicular to the rotation axis in the second section of the magnetic gear according to Embodiment 2. Fig. 9A and Fig. 9B are diagrams showing relations of the x-component of the electromagnetic excitation force and the y-component of the electromagnetic excitation force, respectively, with respect to the rotation angle as reference to the multi-pole mechanism in the magnetic gear element of the magnetic gear according to Embodiment 2. Fig. 10 is a cross-sectional view along the rotation axis showing a configuration of a magnetic gear according to Embodiment 3. Fig. 11 is a cross-sectional view along the rotation axis showing a configuration of a magnetic gear according to Embodiment 4. Fig. 12 is a cross-sectional view along the rotation axis showing a configuration of a magnetic gear according to Embodiment 5. Fig. 13 is a cross-sectional view along the rotation axis showing a configuration of a magnetic gear according to Embodiment 6. Fig. 14A and Fig. 14B are cross-sectional views perpendicular to the rotation axis of the first portion and the second portion, respectively, of a magnetic gear element having the two-stage structure constituting the magnetic gear according to Embodiment 6. Fig. 15 is a diagram showing a relationship between the circumferential position in a magnetic gap between a multi-pole mechanism and a pole piece and the second-order component of the electromagnetic excitation force in the magnetic gear according to Embodiment 6. Fig. 16A and Fig. 16B respectively show a relationship between the circumferential position in a magnetic gap between the multi-pole mechanism and the pole piece of the magnetic gear and the second-order component of the electromagnetic excitation force, and a relationship between the phase difference of the two sections and the amplitude of the second-order component of the electromagnetic excitation force according to a variation example of Embodiment 6. Fig. 17 is a cross-sectional view along the rotation axis showing a configuration of a magnetic gear according to Embodiment 7. Fig. 18A and Fig. 18B are cross-sectional views perpendicular to the rotation axis of the first portion and the second portion, respectively, of a magnetic gear element having the two-stage structure constituting the magnetic gear according to Embodiment 7. Embodiments of the InventionEmbodiment 1

[0014] Fig. 1 to Fig. 4 are diagrams for describing the configuration and operation of a magnetic gear according to Embodiment 1, Fig. 1 is a cross-sectional view along a rotation axis, including the rotation axis and showing the configuration of the magnetic gear, Fig. Figure 2A is a cross-sectional view perpendicular to the rotation axis and corresponds to line AA in Fig. 1 in a first section of a magnetic gear element with a two-stage structure having different specifications in the axial direction, and Fig. Figure 2B is a cross-sectional view perpendicular to the rotation axis and corresponds to line BB in Fig. 1 of a second section.

[0015] It should be noted that in Fig. 1 The following applies: In order to emphasize the areas formed of a magnetic material that produces a gear action of the magnetic gear element, the remaining components are shown without hatching, although they are cross-sectional views, and below, cross-sectional views along the rotation axis are drawn in the same way.

[0016] Fig. 3A shows a relation between x-components of electromagnetic excitation forces (in PU units) of the first section, the second section, and an overall gear section with respect to the rotation angle in an electrical angle with reference to a multi-pole mechanism in the magnetic gear element, Fig. 3B shows the relation between y-components of the electromagnetic excitation forces (in PU units) of the first section, the second section and the entire gear section with respect to the rotation angle in the electrical angle with reference to the multi-pole mechanism in the magnetic gear element, and Fig. Figure 4 is a vector diagram of the electromagnetic excitation force generated in multipole mechanisms in the first section and the second section.

[0017] The magnetic gear of the present invention according to Embodiment 1 has two rotors and a stator as the flux-modulated type magnetic gear, and each of the rotors and the stator corresponds to any one of a multi-pole mechanism, a few-pole mechanism, and a pole piece. More specifically, as shown in Fig. 1, an example will be described in which a magnetic gear element 5 is configured by concentrically arranging the few-pole mechanism 2, which is a first rotor, on one side near the rotation axis X, the multi-pole mechanism 4, which is a second rotor and is located outside the few-pole mechanism 2 with a gap therebetween, and the pole piece 3, which is a stator in the gap.

[0018] In the magnetic gear element 5, between a first section 5a and a second section 5b, each of the multi-pole mechanism 4, the lesser-pole mechanism 2, and the pole piece 3 is mechanically connected in the direction of the rotation axis X (axial direction). The arrangement of the three mechanisms (multi-pole mechanism 4, lesser-pole mechanism 2, and pole piece 3) in the first section 5a and the arrangement of the three mechanisms in the second section 5b are predetermined such that the phase relationship of one mechanism with respect to at least one other of the three mechanisms is different between the first section 5a and the second section 5b. As a result, the magnetic gear element 5 forms a stepped slope between the first section 5a and the second section 5b, but the detailed configuration, including the circumferential arrangement of the multi-pole mechanism 4, the lesser-pole mechanism 2, and the pole piece 3, will be described later.

[0019] The rotors (multipole mechanism 4 and few-pole mechanism 2) of the magnetic gear 1 are each supported by a plurality of bearings 9. A region formed by a magnetic material and generating the gearing action is formed by a bearing shell 8b and a frame 8f formed by a structural member made of iron, a non-magnetic material, or the like.

[0020] With these structures, the driving force generated by a rotating electric machine (not shown) connected to a few-pole rotor shaft 6 on one end side or a multi-pole rotor shaft 7 on the other end side along the rotation axis X (axial direction) is decreased in speed and increased in torque or increased in speed and decreased in torque by the magnetic gear element 5, and is transmitted from the shaft on the opposite side. Magnetic gear element

[0021] A basic configuration of the magnetic gear element 5 is described with reference to Fig. 2A, with the cross section perpendicular to the rotation axis X shown in the first section 5a. The magnetic gear 1 is formed by concentrically arranging the multi-pole mechanism 4 provided with permanent magnets, the few-pole mechanism 2 having a smaller number of poles than the multi-pole mechanism 4, and the pole piece 3 made of a soft magnetic material arranged relative to them via a magnetic gap region. Permanent magnets 4m and permanent magnets 2m serving as magnetic poles are magnetized in the radial direction, and they are arranged such that the polarities of the permanent magnets adjacent to each other in the circumferential direction are reversed (N, S, N, S, .: arrows in the drawing), similar to a rotating electric machine.

[0022] The number of permanent magnets 2m (the number of poles Np2) in the few-pole mechanism 2 is 6, the number of permanent magnets 4m (the number of poles Np4) in the multi-pole mechanism 4 is 28, and the pole piece 3 is formed by 17 magnetic pole pieces (number of poles Np3 = 17).

[0023] That is, the gear ratio of the magnetic gear element 5 in the magnetic gear 1 according to Embodiment 1 is (28 / 2) / (6 / 2), that is, 4.67, and the rotational force of the few-pole rotor shaft 6 is reduced to 1 / 4.67 times, and the torque is increased to 4.67 times and output to the multi-pole rotor shaft 7.

[0024] The greatest common divisor of the number of poles Np2 in the few-pole mechanism 2 and the number of poles Np3 in pole piece 3, and the greatest common divisor of the number of poles Np4 in the multi-pole mechanism 4 and the number of poles Np3 in pole piece 3 are both 1. As a result, the order of the cogging torque in the few-pole mechanism 2 or pole piece 3, which is determined by the lowest common multiple of the number of poles Np2 in the few-pole mechanism 2 and the number of poles Np3 in pole piece 3, can be increased. In addition, the order of the cogging torque in the multi-pole mechanism 4 or pole piece 3, which is determined by the lowest common multiple of the number of poles Np4 in the multi-pole mechanism 4 and the number of poles Np3 in pole piece 3, can also be increased.

[0025] Since it is known that cogging torque typically decreases in magnitude as the order increases, the cogging torque generated in the magnetic gear 1 can be reduced by using such a configuration of the number of poles (number of poles Np2, number of poles Np3, number of poles Np4). As a result, torque pulsation of the input shaft and output shaft of the magnetic gear 1 can be suppressed, and the controllability of the rotating electric machine and the load connected to the magnetic gear 1 can be improved.

[0026] Since the greatest common divisor is 1, the spatial symmetry is again one period (the first order in the spatial order) in the mechanical angle, and the electromagnetic excitation force of the first order in the spatial order is generated in each of the multipole mechanism 4, the few-pole mechanism 2 and the pole piece 3.

[0027] The electromagnetic excitation force of the first order in the spatial order causes the bearing 9 or the frame 8f to vibrate at a low frequency, and thus it becomes a factor for increasing noise and vibration, but these can be reduced by forming the magnetic gear element 5 such that a plurality of sections (first section 5a and second section 5b) having different phases in the axial direction are connected, which will be described in detail later.

[0028] Since the sections with different phases are connected along the axial direction, namely, in the permanent magnets 2m and the permanent magnets 4m used in each of the sections (first section 5a and second section 5b), surfaces extending in the axial direction are all parallel to the axial direction, and thus the shape is simplified (in the present embodiment, the shape is a brick or plate shape). Unlike the case where the continuous skew is formed, mass production is easy, and the manufacturing cost can be reduced.

[0029] Next, the arrangement difference (phase) between the first section 5a and the second section 5b is described. Here, a line segment La is set as a reference position in the circumferential direction in the first section 5a in Fig. 2A. The line segment La denotes the direction of any position in the circumferential direction at the time when the multipole mechanism 4, the few-pole mechanism 2 and the pole piece 3 in the first section 5a are in the position relation (phase relation) shown in Fig. 2A. In the drawing, for simplicity, the direction directly above the drawing is defined as the line segment La.

[0030] The arrangement of the multi-pole mechanism 4, the less-pole mechanism 2 and the pole piece 3 in the second section 5b at the same time as when the first section 5a as in Fig. 2A is arranged in Fig. 2B. The second portion 5b has a configuration in which the arrangement of the first portion 5a is rotated counterclockwise by 180° up to a line segment Lb with reference to the line segment La.

[0031] When comparing the phases of the multi-pole mechanism 4, the lesser-pole mechanism 2, and the pole piece 3 with those of the first section 5a, the phase of the multi-pole mechanism 4 matches that of the first section 5a, and the arrangement is the same. In contrast, in the configuration, the lesser-pole mechanism 2 and the pole piece 3 have different phases, and consequently, the cross-sectional shape is different. That is, the magnetic gear element 5 forms the stepped slope between the first section 5a and the second section 5b.

[0032] The in-phase mechanism with the first section 5a does not require axially out-of-phase stacking, and the manufacturing equipment can be shared with the first section 5a. Therefore, the manufacturing equipment for phase-out stacking is unnecessary, and an increase in manufacturing costs can be suppressed. The effect is generally achieved by arranging a section in which at least one of the pole piece 3, the few-pole mechanism 2, and the multi-pole mechanism 4 has a different phase for two or more sections in the axial direction.

[0033] Next, the operation and characteristics of the magnetic transmission 1 having the above-described magnetic transmission element 5 with the two-stage structure will be described. The x-component and the y-component of the electromagnetic excitation force generated in the multi-pole mechanism 4 of each of the first section 5a and the second section 5b constituting the magnetic transmission element 5 of the magnetic transmission 1 according to Embodiment 1 are as shown in Fig. 3A and Fig. 3B. It can be seen that when a rotation of one period (360°) in the electrical angle is performed with the magnetic pole of the multipole mechanism 4 as a reference, there are components oscillating in the same period in the x-axis direction and the y-axis direction.

[0034] That is, as described above, it turns out that the electromagnetic excitation force of one period (first order in the spatial order) is generated in the mechanical angle with respect to the circumferential direction of the multipole mechanism 4 in each of the first section 5a and the second section 5b. Since the first section 5a and the second section 5b have a relationship of being rotated by the mechanical angle of 180° in the arrangement, the phases of the electromagnetic excitation forces of the first order in the spatial order are also rotated by 180°, and the phases of the x-component and the y-component are inverted, as shown in the figure.

[0035] As a result, it is found that a value obtained by adding the electromagnetic excitation forces of the first portion 5a and the second portion 5b, that is, the electromagnetic excitation force of the entire magnetic gear element 5, is hardly generated.

[0036] The relation between x-component and y-component at a rotation angle of 120° in Fig. 3A and Fig. 3B is represented by a vector diagram as in Fig. 4 shown. In Fig. 4, the trajectories of the vectors for the first section 5a and the second section 5b are shown with a solid line and a dotted line, respectively.

[0037] The vectors of the electromagnetic excitation forces at a rotation angle of 120° are inverted by 180° between the first section 5a and the second section 5b. When added together (magnetic gear element 5), they essentially equal 0, and it can be seen that the electromagnetic excitation forces are canceled out by the electromagnetic excitation forces of equal strength and reversed vectors, and consequently, no electromagnetic excitation force is generated.

[0038] Since the vectors of the electromagnetic excitation forces of the first section 5a and the second section 5b rotate along the trajectories while maintaining a phase relationship of 180°, it is understood that the electromagnetic excitation force suppression effect is maintained during one rotation period in the electrical angle. That is, the electromagnetic excitation force suppression effect is maintained even during one rotation period in the mechanical angle (in the present embodiment, since the number of poles Np4 is 28, this corresponds to 14 periods in the electrical angle).

[0039] In view of the pole number relationship described above, it is possible to implement a configuration in which the effect of suppressing the electromagnetic excitation force is achieved while suppressing the cogging torque, and it is possible to achieve both an improvement in the controllability of the rotating electric machine and the load connected to the magnetic gear 1, as well as the reduction in vibration and noise caused by the electromagnetic excitation force of the magnetic gear 1. Variation example

[0040] Fig. 5A is a cross-sectional view perpendicular to the rotation axis and corresponds Fig. 2B in the second section in a magnetic gear according to a variation example of embodiment 1, Fig. Figure 5B is a vector diagram of the electromagnetic excitation force generated in the multipole mechanism, Fig. 6A is a diagram showing a relationship between the circumferential position and the first-order component of the electromagnetic excitation force in the multi-pole mechanism of the magnetic gear, and Fig. 6B is a diagram showing a relationship between the phase difference (phase shift) of the two sections and the amplitude of the first-order component of the electromagnetic excitation force of the entire magnetic gear element.

[0041] The present variation example is the same as that described in Embodiment 1, except that the arrangement in the second section is different, and the first section has the arrangement described with reference to Fig. 2A. As described in Fig. 5A, the second section 5b of the magnetic gear 1 according to the variation example is such that the arrangement from the first section 5A to the line segment Lb is rotated by the phase shift θ with respect to the line segment La. That is, the case where θ has a value of 180° corresponds to the arrangement shown in Fig. 2B and described in Embodiment 1, and the present variation example shows a configuration in which the rotation angle is generalized.

[0042] The relation between the vectors of the electromagnetic excitation forces is such that the first section 5a and the second section 5b have a phase difference θ, as in Fig. 5B. Then, it is understood that the electromagnetic excitation force of the entire magnetic gear element 5, indicated by the added vector, fluctuates depending on the phase difference between the first portion 5a and the second portion 5b.

[0043] The relation between the first-order component of the electromagnetic excitation force, represented by the addition of the vectors, is in Fig. 6A shows a distribution of the electromagnetic excitation forces at the circumferential positions of the multipole mechanism 4. Similar to the notation of the vector diagram, it can be seen that the amplitude of the waveform (5: broken line), which indicates the addition of the first-order components in the spatial order of the electromagnetic excitation forces, varies due to the phase difference between the first section 5a and the second section 5b.

[0044] In the case where the arrangement of the second section 5b is shifted in phase from that of the first section 5a by the phase shift θ on a mechanical angle basis, the waveform obtained by adding that of the first section 5a and that of the second section 5b, that is, the relation between the amplitude of the first-order component of the electromagnetic excitation force of the entire magnetic gear element 5 and the phase shift θ, in Fig. 6B shown.

[0045] When the phase shift θ is in the range of greater than 120° and less than 240°, the amplitude of the first-order component of the electromagnetic excitation force can be made smaller than that generated by each of the first section 5a and the second section 5b alone. That is, it is possible to obtain the effect of obtaining the magnetic gear 1 with lower noise than in the case where a magnetic gear element is formed by a single section. Another variation example

[0046] In Embodiment 1 and its variation example (the above-described example), an example is described in which the phases of the multi-pole mechanisms 4 coincide with each other in the cross section rotated by 180° between the first section 5a and the second section 5b, but this is not limiting. For example, even in the case where the phases of the few-pole mechanism 2 or the pole piece 3 coincide with each other by the rotation of 180°, it is possible to reduce the steps of stacking each of the mechanisms in the second section 5b and shifting the phase with respect to the arrangement of the first section 5a, and the same effect of reducing the manufacturing cost can be obtained.

[0047] Furthermore, in each of the above examples, the example in which the pole piece 3 is fixed was described. However, the pole piece 3 may also be configured to be freely rotatable, and the phase can be freely adjusted. Further, the multi-pole mechanism 4 or the few-pole mechanism 2 may be fixed. Furthermore, in each of the above examples, the example in which the two types of sections (first section 5a and second section 5b) are connected in the axial direction is described. However, the same effect can also be achieved with a configuration in which multiple types of sections are combined so that the electromagnetic exciting forces are canceled by adding vectors. Embodiment 2

[0048] In Embodiment 2, the arrangement of the mechanisms in the second section is changed from Embodiment 1. Fig. 7, Fig. 8, Fig. 9A and Fig. 9B are used to describe the configuration and operation of a magnetic gear according to Embodiment 2, Fig. 7 is a cross-sectional view along the rotation axis, including the rotation axis and showing the configuration of the magnetic gear, and Fig. Figure 8 is a cross-sectional view perpendicular to the rotation axis in the second section and corresponds to a line CC in Fig. 7.

[0049] Fig. 9A is a diagram showing the relation of the x-components of the electromagnetic excitation forces of the first section, the second section and the entire gear part with respect to the rotation angle in the electrical angle with reference to the multi-pole mechanism in the magnetic gear element, and Fig. 9B is a diagram showing the relation of the y-components of the electromagnetic excitation forces of the first section, the second section, and the entire gear part with respect to the rotation angle in electrical angle with reference to the multi-pole mechanism in the magnetic gear element.

[0050] The magnetic transmission 1 according to Embodiment 2 is the same as that of Embodiment 1 except that the arrangement configuration of the mechanisms in the second section 5b described in Embodiment 1 is replaced, and it is referred to Fig. 2A according to Embodiment 1. The second portion 5b is arranged to lead in phase with respect to the time lapse of the first portion 5a so that it is in a phase relationship capable of cancellation by addition with the first-order component of the electromagnetic force of the first portion 5a.

[0051] As in Fig. 7 and Fig. 8, the second section 5b is arranged to be rotated by 30° in electrical angle with respect to the multi-pole mechanism 4 with respect to the first section 5a, which is formed using Fig. 2A. When time has elapsed for a rotation of 30° in the electrical angle with respect to the multipole mechanism 4, the direction in which the multipole mechanism 4 rotates from the line segment La is denoted by Lb4, and the direction in which the few-pole mechanism 2 rotates from the line segment La is denoted by Lb2.

[0052] Consequently, at the time for the rotation by 30° in the electrical angle with respect to the multipole mechanism 4 with respect to the line segment La in the first section 5a, the multipole mechanism 4 rotates to the position of the line segment Lb4, and the few-pole mechanism 2 rotates to the position of the line segment Lb4.

[0053] More precisely: As in Fig. 8, the multipole mechanism 4 and the few-pole mechanism 2 are rotated so that they are positioned at the line segment Lb4 and the line segment Lb2, respectively, with reference to the line segment La of the first section 5a. As shown in Fig. 9A and Fig. 9B, the configuration is such that the x-component and the y-component of the electromagnetic excitation forces of the first portion 5a and the second portion 5b cancel each other, and the electromagnetic excitation force becomes smaller than that of the single portion.

[0054] As described above, even when the second portion 5a having the arrangement obtained by rotating the arrangement with respect to the first portions 5b with time are connected along the axial direction, the same effect as that of Embodiment 1 can be obtained. Variation example

[0055] In Embodiment 2, the pole piece 3 is fixed, and thus, the example shown is that the phase of the pole piece 3 coincides with each other in the first section 5a and the second section 5b. However, it is apparent that the same effect can be achieved even in the case where the multi-pole mechanism 4 or the few-pole mechanism 2 is fixed and the remaining two mechanisms are freely rotatable.

[0056] In Fig. 8, the second section 5b is configured to have the arrangement for rotation by 30° in the electrical angle with respect to the multi-pole mechanism 4 with respect to the arrangement of the first section 5a, but this is not a limitation. It is apparent that a similar effect can be achieved even if the second section 5b is configured to have a arrangement for rotation by a different electrical angle, which enables cancellation of vibrations due to the electromagnetic excitation force.

[0057] For example, the case where the arrangement of each mechanism in the second section 5b at this time is an arrangement at the time for rotation by α degrees (0° ≤ α ≤ 360°) in the electrical angle with respect to the multipole mechanism 4 with respect to the first section 5a will be described as an example. That is, when the time for rotation by α degrees in the electrical angle with respect to the multipole mechanism 4 has elapsed, the direction in which the multipole mechanism 4 rotates from the line segment La is defined as Lb4, and the direction in which the few-pole mechanism 2 rotates from the line segment La is defined as Lb2.

[0058] With reference to the line segment La in the first section 5a, at the time of rotation by α degrees in the electrical angle with reference to the multipole mechanism 4, the multipole mechanism 4 may be configured to rotate to the position of the line segment Lb4, and the few-pole mechanism 2 may be configured to rotate to the position of the line segment Lb4.

[0059] In Embodiment 2, including the variation example, the example in which the pole piece 3 is fixed is described. However, the pole piece 3 can also be configured to rotate freely, and thus the phase can be freely adjusted. Furthermore, the multi-pole mechanism 4 or the few-pole mechanism 2 can be fixed.

[0060] Furthermore, in Embodiment 2, the example in which two types of sections (first section 5a and second section 5b) are connected in the axial direction is described. However, the same effect can also be achieved by combining more types of sections to cancel the electromagnetic excitation forces by adding vectors. Embodiment 3

[0061] Embodiment 1 and Embodiment 2 describe examples of the magnetic gear element having a two-stage structure where the first portion and the second portion are connected in the axial direction. Embodiment 3 describes an example of the magnetic gear element having a three-stage structure. Fig. 10 is a cross-sectional view taken along a rotation axis and including the rotation axis in the magnetic gear, for describing the configuration and operation of a magnetic gear according to Embodiment 3. Note that a third section is arranged in the same manner (in the same phase) as the first section, and the first section and the second section are arranged in the same manner as described in Embodiment 1 or Embodiment 2.

[0062] Therefore, their description is omitted and reference is made to Fig. 2A to Fig. 9B.

[0063] In the magnetic gear 1 according to Embodiment 3, as illustrated in Embodiment 1 or Embodiment 2, the second portion 5b, whose phase is different from the first portion 5a in at least one of the few-pole mechanism 2, the multi-pole mechanism 4, and the pole piece 3, is adjacent to the first portion 5a in the axial direction. As shown in Fig. 10, on the opposite side of the second portion 5b with respect to the first portion 5a in the axial direction, a third portion 5c in which each mechanism is arranged in the same phase as the first portion 5a is connected so as to form the three-stage structure.

[0064] The present embodiment differs from Embodiment 1 or Embodiment 2 in that the number of adjacent regions of the different-phase sections is two, whereas the number of adjacent regions of the different-phase sections in Embodiment 1 or Embodiment 2 is one, and the other configurations are the same as those in Embodiment 1 or Embodiment 2.

[0065] By arranging the sections with different phases (first section 5a, second section 5b and third section 5c) so that they are arranged and distributed or scattered in the axial direction, it is possible to suppress deflection in a direction perpendicular to the axial direction due to the bending moment caused by the combination of the electromagnetic excitation forces with different phases in the circumferential direction.

[0066] Regarding the distribution of the areas in the axial direction over the sections with arrangements having different phases, the configuration in which the effect of suppressing the deflection is optimal differs depending on the positional relationship between the rotor and the bearing 9 or the mounting positions with respect to the load and the rotating electrical machine. Fig. 10 shows, as an example, a configuration in which the ratio of stacking the thicknesses of the first portion 5a, the second portion 5b, and the third portion 5c in the axial direction is 1:2:1.

[0067] From the point of view of canceling the electromagnetic excitation forces, it is desirable that the stack thicknesses in the axial direction in an arrangement pattern A through the first section 5a and the third section 5c coincide with the stack thicknesses in the axial direction in an arrangement pattern B through the second section 5b.

[0068] In Embodiment 3, the example in which the magnetic gear element 5 is configured by connecting three sections in the axial direction is described. However, even in a case where there are four or more sections, it is possible to further reduce the deflection in the direction perpendicular to the axial direction, and the same effect is achieved. Further, in Embodiment 3, the configuration example in which the sections of two types of arrangement patterns are connected in the axial direction is shown, but the same effect can be achieved by combining two or more types of sections so that the electromagnetic excitation forces are canceled by the addition of the vectors. Embodiment 4

[0069] In Embodiment 1 and Embodiment 2 described above, examples are described in which the first portion and the second portion are connected in close contact with each other in the axial direction and form the magnetic gear element. In Embodiment 4, an example is described in which the first portion and the second portion are connected to each other via a magnetic hollow portion and form a magnetic gear element.

[0070] Fig. 11 is a cross-sectional view taken along a rotation axis and including the rotation axis in the magnetic transmission, for describing the configuration and operation of a magnetic transmission according to Embodiment 4. It should be noted that the arrangement of the mechanisms in each of the first section and the second section is the same as the arrangement described in Embodiment 1 or Embodiment 2, and the description thereof is omitted, and reference is made to Fig. 2A to Fig. 9B is referred to.

[0071] As in Fig. As shown in FIG. 11, the magnetic gear 1 according to Embodiment 4 is the same as that in Embodiment 1 or Embodiment 2, except that a magnetic hollow portion 5g is disposed between the first portion 5a and the second portion 5b in the axial direction using air, a non-magnetic material, or the like. By disposing the magnetic hollow portion 5g between the first portion 5a and the second portion 5b with different phases, it is possible to reduce the axial direction leakage flux that does not contribute to the torque transmission of the magnetic gear 1.

[0072] Therefore, it is possible to suppress a decrease in the transmission torque due to the formation of the magnetic gear element 5 by connecting the sections with different phases (first section 5a and second section 5b). Variation example

[0073] Although Fig. 11 shows the example where the small magnetic hollow portion 5g is arranged in the axial direction to reduce the size of the magnetic gear 1, but this is not a limitation. Even if the first portion 5a and the second portion 5b are separated from each other in the axial direction and connected to each other by a structural member to ensure the magnetic hollow portion 5g, the same effect can be achieved.

[0074] Furthermore, the first section 5a and the second section 5b may be sections formed of different structural elements, and each of the rotors (in this example: the multi-pole mechanism 4 and the few-pole mechanism 2) may be connected to each other by means of a structural element. Embodiment 5

[0075] In Embodiment 5, the magnetic hollow portion is arranged between the sections as in Embodiment 4 with respect to the magnetic gear element, connecting the three sections described in Embodiment 3. Fig. 12 is a cross-sectional view taken along a rotation axis and including the rotation axis in the magnetic transmission, for describing the configuration and operation of a magnetic transmission according to Embodiment 5. It should be noted that the arrangement of the mechanism in each of the first section, the second section, and the third section is the same as that described in Embodiment 3, and thus the description thereof is omitted, and reference is made to Fig. 2A to Fig. 9B.

[0076] As in Fig. 12, the magnetic gear 1 according to Embodiment 5 is the same as that of Embodiment 3, except that the magnetic hollow portion 5g is arranged using air, a non-magnetic material, or the like between the first portion 5a and the second portion 5b and between the second portion 5b and the third portion 5c in the axial direction.

[0077] By arranging the first section 5a, the second section 5b, and the third section 5c with different phases so that they are arranged and dispersed in the axial direction, deflection in the direction perpendicular to the axial direction is suppressed. Furthermore, by arranging the magnetic hollow portion 5g between them, it is possible to reduce the axial direction leakage flux that does not contribute to the torque transmission of the magnetic gear 1. Variation example

[0078] Although Fig. 12 shows the example where the small magnetic hollow portion 5g is arranged in the axial direction to reduce the size of the magnetic gear 1, but this is not a limitation. The same effect can be achieved even with a configuration in which the first portion 5a, the second portion 5b, and the third portion 5c are further separated from each other in the axial direction, and the magnetic hollow portion 5g is secured by connecting them with a structural member.

[0079] Furthermore, the first section 5a, the second section 5b and the third section 5c may be sections formed of different structural elements, and each of the rotors (in the present example, the multi-pole mechanism 4 and the few-pole mechanism 2) may be connected to each other by means of a structural element.

[0080] Further, in the same manner as in Embodiment 3, the example in which the portions of the two kinds of arrangement patterns are connected in the axial direction is shown, but the same effect can be achieved by combining more kinds of portions to cancel the electromagnetic exciting forces by the addition of the vectors. Embodiment 6

[0081] In a magnetic gear according to Embodiment 6, an example will be described in which a magnetic gear element is configured by a combination of the number of polarities different from those in Embodiment 1 to Embodiment 5. Fig. 13 to Fig. 15 are diagrams for describing the configuration and operation of a magnetic gear according to Embodiment 6, and Fig. 13 is a cross-sectional view along the rotation axis, including the rotation axis and showing the configuration of the magnetic gear, Fig. 14A is a cross-sectional view perpendicular to the rotation axis in the first section and corresponds to a line DD in Fig. 13, and Fig. Figure 14B is a cross-sectional view perpendicular to the rotation axis in the second section and corresponds to a line EE in Fig. 13. Fig. 15 is a diagram showing the relationship of the electromagnetic excitation forces of the second-order components of the first section, the second section, and the entire gear part with respect to the circumferential position in the magnetic gap between the multipole mechanism and the pole piece in the magnetic gear element.

[0082] The following applies to the magnetic gear 1 according to embodiment 6: As in Fig. 13 and Fig. 14A, the section is formed by the multi-pole mechanism 4 in which 22 (number of poles Np4) permanent magnets 4m are arranged, the few-pole mechanism 2 in which 6 (number of poles Np2) permanent magnets 2m are arranged, and the pole piece 3 which is formed by 14 (number of poles Np3) magnetic pole pieces.

[0083] That is, the gear ratio of the magnetic gear 1 when the pole piece 3 is fixed is 3.67, that is, (22 / 2) / (6 / 2). The greatest common factor of the number of poles Np2 of the few-pole mechanism 2 and the number of poles Np3 of the pole piece 3, and the greatest common factor of the number of poles Np4 of the multi-pole mechanism 4 and the number of poles Np3 of the pole piece 3 are both 2. Since the greatest common factor of the number of poles is 2, the lowest common multiple of the number of poles can be made sufficiently large, as in Embodiment 1, and the amplitude of the cogging torque can be reduced.

[0084] As in Fig. 14B, the second portion 5b has a shape obtained by rotating the second portion 5b relative to the first portion 5a by 90° in mechanical angle with reference to the line segment La. The present embodiment is the same as Embodiment 1 to Embodiment 5 described above, except that the first portion 5a is different from the arrangement shown in Fig. 2A is replaced by the arrangement shown in Fig. 14A, and the second section 5b of the arrangement shown in Fig. 2B is replaced by the arrangement shown in Fig. 14B is shown.

[0085] In the configuration of the number of poles shown in Embodiment 6, since the spatial symmetry is of the second order, an electromagnetic excitation force is generated that has a second-order spatial mode in the circumferential direction. As shown in Fig. 15, since the first section 5a and the second section 5b have the phase difference of 90° in mechanical angle, it is understood that the spatial waveforms of the second-order components of the electromagnetic excitation forces generated in the multipole mechanism 4 cancel each other due to the phase relation of the second-order electromagnetic excitation forces when they are added to each other. Variation example

[0086] Fig. 16A is a diagram showing the relation of the circumferential position in the magnetic gap between the multi-pole mechanism and the pole piece in the magnetic gear element with respect to the second-order components of the electromagnetic excitation forces according to a variation example of Embodiment 6, and Fig. 16B is a diagram showing the relationship between the phase difference (phase shift) of the two sections and the amplitude of the second-order component of the electromagnetic excitation force of the entire magnetic gear element.

[0087] In the present variation example, it is described that the same effect can be achieved even if the phase difference of the mechanical angle is other than 90°. In the arrangement of the second section 5b, the angle of the line segment Lb changes with respect to the line segment La, which in Fig. 14B, from 90° to θ. That is, the case where θ has a value of 90° corresponds to the arrangement shown in Fig. 14B and described in Embodiment 6, and the present variation example shows a configuration in which the rotation angle is generalized.

[0088] As in Fig. As shown in Figure 16A, it can be seen that, even when the phase difference θ is not 90°, the amplitude of the second-order spatial component of the electromagnetic excitation force can be made smaller by the addition than the amplitude in the case where each of the sections is used alone. The amplitude of the second-order spatial component of the electromagnetic excitation force when the phase difference θ is changed from 0 to 360° changes as shown in Fig. 16B shown.

[0089] When the phase difference θ is in a range greater than 60° and less than 120° or in a range greater than 240° and less than 300°, the amplitude of the second-order spatial component of the electromagnetic excitation force can be reduced compared with the case where each section is used alone. Another variation example

[0090] In Embodiment 6 and its variation example, the example in which the pole piece 3 is fixed was described. However, a configuration in which the pole piece 3 is configured to be freely rotatable, and thus the phase can be freely adjusted, may also be adopted. Further, as the configuration of the magnetic gear element 5, the example in which the two types of sections shown in Fig. 1 of Embodiment 1 are connected in close contact with each other in the axial direction, but this is not limiting. The same effect can be achieved with configurations similar to Embodiment 3 to Embodiment 5. Embodiment 7

[0091] In a magnetic gear according to Embodiment 7, an example will be described in which a magnetic gear element is configured by a combination of the number of polarities different from those in Embodiment 1 to Embodiment 5 and Embodiment 6. Fig. 17, Fig. 18A and Fig. 18B are used to describe the configuration and operation of a magnetic gear according to Embodiment 7, Fig. 17 is a cross-sectional view along the rotation axis, including the rotation axis and showing the configuration of the magnetic gear, Fig. 18A is a cross-sectional view perpendicular to the rotation axis in the first section and corresponds to a line FF in Fig. 17, and Fig. 18B is a cross-sectional view perpendicular to the rotation axis in the second section and corresponds to a line GG in Fig. 17.

[0092] As in Fig. 17 and Fig. 18A, in the magnetic gear 1 according to Embodiment 7, one section is constituted by the multi-pole mechanism 4 in which 20 (number of poles Np4) permanent magnets 4m are arranged, the few-pole mechanism 2 in which 8 (number of poles Np2) permanent magnets 2m are arranged, and the pole piece 3 constituted by 14 (number of poles Np3) magnetic pole pieces.

[0093] That is, when the pole piece 3 is fixed, the gear ratio of the magnetic gear 1 is 2.5, i.e., (20 / 2) / (8 / 2). The greatest common factor of the number of poles Np2 of the few-pole mechanism 2 and the number of poles Np3 of the pole piece 3, and the greatest common factor of the number of poles Np4 of the multi-pole mechanism 4 and the number of poles Np3 of the pole piece 3 are both 2. Since the greatest common factor of the number of poles is 2, the lowest common multiple of the number of poles can be made sufficiently large, as in Embodiment 6, and the amplitude of the cogging torque can be reduced.

[0094] As in Fig. 18B, the second portion 5b has a shape obtained by rotating the first portion 5a by 90° in mechanical angle with reference to the line segment La. The present embodiment is the same as Embodiment 1 to Embodiment 5 described above, except that the first portion 5a is different from the arrangement shown in Fig. 2A is replaced by the arrangement shown in Fig. 18A, and the second section 5b of the arrangement shown in Fig. 2B is replaced by the arrangement shown in Fig. 18B is shown.

[0095] The phase of the few-pole mechanism 2 of the second section matches that of the first section 5a. Similar to Embodiment 1, the few-pole mechanism 2 does not require axial-direction stacking with phase shift, and thus, the manufacturing equipment can be shared with the first section 5a. Therefore, the manufacturing equipment for phase shift stacking is unnecessary, and an increase in manufacturing costs can be suppressed.

[0096] Although the example in which the phase of the few-pole mechanism 2 is consistent between the first section 5a and the second section 5b has been described in the present embodiment, this is not a limitation. The same effect can be achieved by combining the number of poles and the phase difference θ, so that an arrangement pattern where the phase of at least one of the few-pole mechanism 2 and the multi-pole mechanism 4 is different is arranged two or more in the axial direction.

[0097] In the configuration of the number of poles shown in Embodiment 7, since the spatial symmetry is of the second order, an electromagnetic excitation force having a second-order spatial mode in the circumferential direction is generated.

[0098] As in Fig. 15, since the first section 5a and the second section 5b have the phase difference of 90° in mechanical angle, it is understood that the spatial waveforms of the second-order components of the electromagnetic excitation forces generated in the multipole mechanism 4 cancel each other due to the phase relation of the second-order electromagnetic excitation forces when they are added to each other. Variation example

[0099] In Embodiment 7, the example in which the pole piece 3 is fixed was described. However, a configuration in which the pole piece 3 is configured to be freely rotatable, and thus the phase can be freely adjusted, may also be adopted. Further, as the configuration of the magnetic gear element 5, the example in which the two types of sections shown in Fig.1 of Embodiment 1 are connected in close contact with each other in the axial direction, but this is not limiting. The same effect can be achieved with configurations similar to Embodiment 3 to Embodiment 5.

[0100] Although various exemplary embodiments are described in the present invention, various features, aspects, and functions described in one or more embodiments are not inherent in the application of the contents described in a particular embodiment, and are applicable alone or in various combinations thereof to any embodiment.

[0101] Accordingly, numerous variations not shown can be devised within the scope of the technique disclosed in the description of the present invention. For example, the following are included: the case where at least one component is modified, added, or omitted, and the case where at least one component is extracted and combined with a component disclosed in another embodiment.

[0102] For example, the examples are described in which the permanent magnet (permanent magnets 4m and permanent magnets 2m) of each magnetic pole in the magnetic gear is 1 one for each, but the same effect can be achieved even if the permanent magnet is divided in the magnetization direction, the orthogonal direction with respect to the magnetization direction, the axial direction and other directions.

[0103] Further, examples are shown in which the magnetic gear 1 is of the radial type and has the magnetic gap portion in a direction perpendicular to the rotation axis X, but the same effect can be achieved with an axial type having a magnetic gap portion in a direction parallel to the rotation axis X.

[0104] Furthermore, in each of the above-described embodiments, as a combination of the number of poles Np2, the number of poles Np4, and the number of poles Np3, a total of three combinations of the number of poles, such as the combination example of 6, 28, and 17, the combination example of 6, 22, and 14, and the combination example of 8, 20, and 14, are shown, but this is not a limitation. Furthermore, the cases where the greatest common divisor of the number of poles Np2 and the number of poles Np3 and the greatest common divisor of the number of poles Np4 and the number of poles Np3 are both 1 or 2 are described, but this is not a limitation.

[0105] Of course, if both of these are 1, the first-order spatial component of the electromagnetic excitation force can be reduced to the maximum, and if both of them are 2, the second-order component of the electromagnetic excitation force can be reduced to the maximum. Even if one of them is 1 and the other is 2, it is possible to reduce both the first-order spatial component and the second-order spatial component of the electromagnetic excitation force.

[0106] Furthermore, if one of them is 1 or 2, even if the other of them is neither 1 nor 2, it is possible to reduce the first-order spatial component or the second-order spatial component of the electromagnetic excitation force.

[0107] Considering the above, the same effect can be achieved as long as at least the following three conditions are met simultaneously.

[0108] Condition 1: Two or more sections in which at least one of the pole piece 3, the few-pole mechanism 2 and the multi-pole mechanism 4 has a different phase are arranged in the axial direction.

[0109] Condition 2: At least one of the greatest common divisor of the number of poles Np2 of the few-pole mechanism 2 and the number of poles Np3 of the pole piece 3 and the greatest common divisor of the number of poles Np4 of the multi-pole mechanism 4 and the number of poles Np3 is 1 or 2.

[0110] Condition 3: If the number of pole pairs (= Np2 / 2) of the few-pole mechanism 2 constituting the section is N2, the number of pole pairs (= Np4 / 2) of the multi-pole mechanism 4 is N4, and the number of pole pieces 3 (= Np3) is N3, the relation represented by expression (1) is obtained. (2k−1)N3=N4±(2m−1)N2 where both k and m are natural numbers.

[0111] In addition, the shapes of the teeth of the magnetic gear 1, the pole piece 3, and the permanent magnets (permanent magnets 2m and 4m) are illustrated as the simplest shapes, but they are not limited to these. The shapes of the teeth and the pole piece can be widened or tapered in the radial direction toward the magnetic gap area.

[0112] Furthermore, even in a case where bond magnets are used as permanent magnets, if two or more permanent magnets are used per magnetic pole and embedded in a V shape, the same effect can be achieved regardless of the shapes of the teeth, the pole piece 3 and the permanent magnets, as long as the three conditions described above are met.

[0113] As described above, the magnetic gear of the present invention includes the magnetic gear element 5 configured such that each of the multi-pole mechanism 4, the few-pole mechanism 2, and the pole piece 3 shares a function of any one of the stator, a first rotor, and a second rotor. The multi-pole mechanism 4 has the magnetic poles of the first number of poles (number of poles Np4) arranged along the circumferential direction with the permanent magnets 4m. The few-pole mechanism 2 has the magnetic poles of the second number of poles (number of poles Np2) less than those of the first number of poles (number of poles Np4) and arranged along the circumferential direction with the permanent magnets 2m. The pole piece 3 has the magnetic poles of the third number of poles (number of poles Np3).arranged along the circumferential direction with soft magnetic material through the magnetic gaps with respect to each of the magnetic poles of the multi-pole mechanism 4 and the few-pole mechanism 2; a first shaft (multi-pole rotor shaft 7) for transmitting torque between the first rotor (for example, the multi-pole mechanism 4) and the outside; and a second shaft (for example, the few-pole rotor shaft 6) for transmitting torque between the second rotor and the outside.

[0114] The magnetic gear element 5 is configured such that, between adjacent sections (e.g., the first section 5a and the second section 5b, the second section 5b, and the third section 5c) among a plurality of sections (e.g., the first section 5a, the second section 5b, the third section 5c) divided along an axial direction (the direction of the rotation axis X), the positional relationship of the magnetic poles among the multi-pole mechanism 4, the few-pole mechanism 2, and the pole piece 3 is different such that at least one of the multi-pole mechanism 4, the few-pole mechanism 2, and the pole piece 3 has the phase difference θ, and at least one of the greatest common divisor of the first pole number (number of poles Np4) and the third pole number (number of poles Np3) and the greatest common divisor of the second pole number (number of poles Np2) and the third pole number (number of poles Np3) 1 or 2.Therefore, it is possible to achieve both a reduction in the cogging torque and a reduction in the electromagnetic excitation force without increasing the manufacturing costs.

[0115] In particular, when surfaces extending in the axial direction of the permanent magnets (permanent magnets 4m and permanent magnets 2m) used in the multi-pole mechanism 4 and the few-pole mechanism 2, respectively, are parallel to the axial direction, the magnetic poles can be formed without performing special processing.

[0116] Here, at least one of the greatest common divisor of the first pole numbers and the third pole numbers and the greatest common divisor of the second pole numbers and the third pole numbers is 1, and the plurality of sections are formed by two types of sections, including a section in a first arrangement pattern (for example, the first section 5a) in which the magnetic poles are arranged in the first positional relation, and a section in a second arrangement pattern (for example, the second section 5b) in which the magnetic poles are arranged in the second positional relation, wherein the phase difference θ with respect to the section in the first arrangement pattern (for example, the first section 5a, the third section 5c) is in an angular range greater than 120° and less than 240° on a mechanical angle basis, as the positional relation of the magnetic poles,and then the first-order spatial component of the electromagnetic excitation force can be effectively reduced.

[0117] Alternatively, at least one of the greatest common divisor of the first pole numbers and the third pole numbers and the greatest common divisor of the second pole numbers and the third pole numbers is 1, and the plurality of sections are formed by two types of sections, including a section in a first arrangement pattern (for example, the first section 5a) in which the magnetic poles are arranged in the first positional relation, and a section in a second arrangement pattern (for example, the second section 5b) in which the magnetic poles are arranged in the second positional relation, in which the phase difference θ with respect to the section in the first arrangement pattern (for example, the first section 5a, the third section 5c) is in an angular range that is greater than 60° and less than 120° or greater than 240° and less than 300° on a mechanical angle basis, as the positional relation of the magnetic poles,and then the second-order spatial component of the electromagnetic excitation force can be effectively reduced.

[0118] When the magnetic hollow portion 5g is disposed between adjacent portions (for example, the first portion 5a and the second portion 5b) among the plurality of portions, it is possible to reduce the leakage flux between adjacent portions, so that a reduction in the transmission torque can be suppressed.

[0119] When three or more sections (for example, the first section 5a, the second section 5b, the third section 5c) which are divided are arranged as the plurality of sections, the order of the vibration mode of the bending force in the axial direction can be increased, so that the bending force is reduced.

[0120] In this case, if at least two sections (for example, the first section 5a and the third section 5c) among the three or more sections having the same positional relationship in the magnetic poles among the multi-pole mechanism 4, the few-pole mechanism 2, and the pole piece 3, the order of the vibration mode of the bending force in the axial direction can be increased, so that the bending force is reduced without increasing the number of kinds of components and complicating the process. List of reference symbols 1 magnetic gear, 2 Lesser-pole mechanism, 2m permanent magnet, 3 pole piece, 4 multipole mechanism, 4m permanent magnet, 5 magnetic gear element, 5a first section, 5b second section, 5c third section, 6 Few-pole rotor shaft (first shaft or second shaft), 7 Multipole rotor shaft (second shaft or first shaft), Np2 number of poles (second pole numbers), Np3 number of poles (third pole numbers), Np4 number of poles (first pole numbers), X rotating shaft, θ phase difference 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] WO 2015 / 053005 A1

[0008]

Claims

[1] Magnetic gear comprising: - a magnetic gear element configured such that each of a multi-pole mechanism, a fewer-pole mechanism, and a pole piece shares a function of any one of a stator, a first rotor, and a second rotor, wherein the multi-pole mechanism has magnetic poles of first numbers arranged along the circumferential direction with permanent magnets, the fewer-pole mechanism has magnetic poles of second numbers less than those of the first numbers and arranged along the circumferential direction with permanent magnets, the pole piece has magnetic poles of third numbers arranged along the circumferential direction with soft magnetic material through magnetic gaps with respect to each of the magnetic poles of the multi-pole mechanism and the fewer-pole mechanism; - a first shaft for transmitting a torque between the first rotor and the outside; and - a second shaft for transmitting torque between the second rotor and the outside, wherein in the magnetic gear element, between adjacent sections among a plurality of sections divided along an axial direction, the positional relationship of the magnetic poles among the multi-pole mechanism, the fewer-pole mechanism, and the pole piece is different so that at least one of the multi-pole mechanism, the fewer-pole mechanism, and the pole piece has a phase difference, and at least one of a greatest common divisor of the first pole numbers and the third pole numbers and a greatest common divisor of the second pole numbers and the third pole numbers is 1 or 2. [2] A magnetic gear according to claim 1, wherein surfaces of the permanent magnets extending in the axial direction are parallel to the axial direction, the permanent magnets being used in the multi-pole mechanism and the few-pole mechanism. [3] Magnetic gear according to claim 1 or 2, wherein at least one of a greatest common divisor of the first pole numbers and the third pole numbers and a greatest common divisor of the second pole numbers and the third pole numbers is 1, and the plurality of sections are formed of two types of sections, including a section in a first arrangement pattern in which the magnetic poles are arranged in a first positional relationship, and a section in a second arrangement pattern in which the magnetic poles are arranged in a second positional relationship in which the phase difference with respect to the section in the first arrangement pattern is in an angular range greater than 120° and less than 240° on a mechanical angle basis as the positional relationship of the magnetic poles. [4] Magnetic gear according to claim 1 or 2, wherein at least one of a greatest common divisor of the first pole numbers and the third pole numbers and a greatest common divisor of the second pole numbers and the third pole numbers is 2, and the plurality of sections are formed of two types of sections, including a section in a first arrangement pattern in which the magnetic poles are arranged in a first positional relationship, and a section in a second arrangement pattern, the magnetic poles being arranged in a second positional relationship in which the phase difference with respect to the section in the first arrangement pattern is in an angular range greater than 60° and less than 120° or greater than 240° and less than 300° on a mechanical angle basis, as a positional relationship of the magnetic poles. [5] A magnetic gear according to any one of claims 1 to 4, wherein a magnetic hollow portion is disposed between adjacent sections among the plurality of sections. [6] A magnetic gear according to any one of claims 1 to 5, wherein three or more divided sections are arranged as the plurality of sections. [7] A magnetic gear according to claim 6, wherein at least two sections among the three or more sections have the same positional relation in the magnetic poles.

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