JP6576800B2 - Magnetic gear unit - Google Patents

Description

  The present invention relates to a magnetic gear device in which a driving rotor and a driven rotor transmit power without contact with each other.

Rotating electric motors such as motors are installed in driving parts of automobiles, railways, industrial machines, home appliances and the like. The output of the rotary motor is converted into a desired torque or rotation speed by a gear or the like and transmitted to the action portion. In a conventional general mechanical gear, a pair of gear teeth meshing with each other transmits power while being in contact with each other, so that friction occurs between the teeth. Therefore, there were the following problems.
・ The teeth are worn and worn.
・ Vibration and noise are generated.
・ Tooth is damaged due to limit torque or fatigue failure.
-Lubricants such as oil and grease are required and cannot be used in a clean environment.

All of the above problems will be solved if there is no contact between the teeth. There is a magnetic gear as a power transmission mechanism without contact between teeth. Since the magnetic gear is characterized by transmitting power without contact, the absolute value of transmittable torque is lower than that of a mechanical gear, but has the following many merits.
・ There is almost no vibration and noise.
・ No dust generation. For this reason, it can be used in a clean environment.
・ Almost no deterioration due to friction and wear, and maintenance-free.
・ Power can be transmitted even if there is a partition wall (non-magnetic material) between teeth. For this reason, it is possible for two teeth to exist in different media.
-Has a torque limiter function that steps out when torque exceeding the capacity is applied. If the mechanical gear receives more torque than it can, the teeth may be damaged.
・ Since there is no friction loss, highly efficient torque transmission is possible depending on the configuration.

Patent Documents 1 and 2 describe a speed change mechanism using a magnetic gear.
In the magnetic gear device of Patent Document 1, the driving side and driven side rotors (external gears, internal gears) are arranged concentrically, and a stator (stator gear) is interposed between the rotors. Each rotor and the stator are opposed to each other via a radial gap. The stator is provided with a plurality of pole pieces (magnetic tooth portions) arranged in the circumferential direction. By using the laminated conductive magnetic steel plates in this pole piece, to reduce eddy currents during rotation, thereby making it possible to shift at high efficiency. Furthermore, the pole piece is skewed with respect to the axial direction, thereby reducing a steep change in the magnetic field and suppressing the cogging torque.

  The magnetic gear mechanism of Patent Document 2 also includes a stator (a magnetic pole piece) that is opposed to each of the two rotors via a radial gap between the two rotors. In Patent Document 2, a structure in which a permanent magnet of a rotor is embedded in a soft magnetic material enables a large torque transmission, and further, the permanent magnet is divided in the axial direction so that the inside of the rotating magnet This reduces the eddy current generated in the motor and enables highly efficient torque transmission.

Patent No. 5389122 Japanese Patent No. 5526281

  As described above, in the speed change mechanism using the magnetic gears of Patent Documents 1 and 2, both the driving side and driven side rotors face the stator via the radial gap. With this configuration, the overall radial dimension is increased. Therefore, in order to suppress the overall radial dimension, one of the driving side and driven side rotors faces the stator via a radial gap, and the other rotor faces the stator via an axial gap. Attempts were made to develop a magnetic gear device having a configuration opposite to.

In the case where the two rotors are both opposed to the stator via a radial gap or the two rotors are both opposed to the stator via an axial gap, the magnetic flux flow is directional. it is effective to use a laminated conductive magnetic steel plate pieces. However, in the configuration that combines the radial gap and axial gap, since the magnetic flux flows in pole piece is three dimensional, the use of laminated conductive magnetic steel plate pole pieces, one direction of the vortex of the radial and axial directions Tests have confirmed that only the current component can be reduced and the torque transmission efficiency is reduced.

  An object of the present invention is to provide a three-dimensional configuration in which one of the two rotors faces the stator via a radial gap and the other rotor faces the stator via an axial gap. An object of the present invention is to provide a magnetic gear device capable of suppressing eddy current loss of flowing magnetic flux and realizing high torque transmission efficiency.

  A magnetic gear device according to the present invention includes two rotors each having a plurality of permanent magnets, and a stator having a plurality of pole pieces magnetically positioned between the two rotors and capable of modulating magnetic flux. One rotor of the two rotors faces the stator through a radial gap in a direction perpendicular to the rotation axis of the rotor, and the other of the two rotors rotates. The rotor is opposed to the stator via an axial gap in a direction parallel to the rotation axis of the rotor, and the pole piece is configured using a dust core.

  According to this configuration, the rotation of the rotor on the driving side is transmitted to the rotor on the driven side at a gear ratio according to the number of pole pairs of the permanent magnets of both rotors. One of the two rotors faces the stator via a radial gap, and the other rotor faces the stator via an axial gap, so that both rotors go through a radial gap. Therefore, the radial dimension of the entire magnetic gear device can be suppressed as compared with the configuration facing the stator. Further, the axial dimension of the entire magnetic gear device can be reduced as compared with the configuration in which the two rotors both face the stator via the axial gap.

  In the case of a configuration in which one of the two rotors faces the stator via a radial gap and the other rotor faces the stator via an axial gap, the magnetic flux flowing through the pole piece of the stator The direction is three-dimensional. For example, the direction of the magnetic flux acting between the magnetic poles of one rotor and the other rotor is approximately the direction of the rotation axis of each rotor, but faces the vicinity of the magnetic pole boundary of one rotor or the other rotor. The magnetic flux is generated in the circumferential direction at the portion where the magnetic flux is present. For this reason, if the pole piece is composed of laminated electromagnetic steel sheets having only a two-dimensional magnetic flux direction suppressing effect, the effect of reducing eddy current loss is weak and torque transmission efficiency is reduced. However, if the pole piece is configured using a dust core as in the configuration of the present invention, the effect of reducing the eddy current in the three-dimensional magnetic flux direction is high, so eddy current loss is suppressed and torque transmission efficiency is improved. Can be improved.

In the present invention, in the other rotor, the plurality of permanent magnets may be arranged at equal intervals on the same circumference so that the directions of magnetic poles of two adjacent permanent magnets are different from each other. In the other rotor, the plurality of permanent magnets may be arranged in a Halbach array.
In either case, eddy current loss can be suppressed and torque transmission efficiency can be improved.

In the present invention, at least the portion of the pole piece that faces the one rotor has a cross-sectional area that is perpendicular to the rotation axis of the one rotor as it approaches the other rotor. good. The cross-sectional area may increase continuously as it approaches the other rotor, or may increase stepwise.
From the viewpoint of torque transmission performance between the two rotors, it is desirable that the magnetic fluxes act between the two rotors without waste. If the cross-sectional area of the pole piece increases as it approaches the other rotor, the flow of magnetic flux in the pole piece becomes smoother, and the leakage flux generated at a location far away from the other rotor in the pole piece is minimized. It can be suppressed to the limit. As a result, the magnetic flux acting on the other rotor increases, and the transmission torque and transmission efficiency are improved.

A portion of the pole piece other than the portion facing the one rotor may have a cross-sectional area that is perpendicular to the rotation axis of the one rotor as the other rotor is approached.
In the case of a magnetic gear device in which the number of poles of the other rotor is large, if the axial cross-sectional area of the part other than the part facing the one rotor of the pole piece becomes larger as it approaches the other rotor, the pole piece There is a possibility that the facing area of the other rotor becomes too large, and one pole piece faces the circumferentially adjacent N pole and N pole or S pole and S pole. Therefore, by reducing the axial cross-sectional area of the portion other than the portion facing the one rotor of the pole piece as it approaches the other rotor, the area facing the other rotor of the pole piece is reduced, Avoid straddling the pole piece.

In this invention, the surface of the pole piece facing the other rotor has two concentric arcs having different radii around the rotation axis of the other rotor, and the other rotor has A fan shape surrounded by two straight lines extending radially from the rotation axis in different directions may be used.
When the shape of the surface of the pole piece facing the other rotor is a substantially square shape, it is the same phenomenon as adding a skew angle when compared to a motor, and it can be expected to suppress cogging torque and torque ripple. On the other hand, the maximum torque decreases. When the shape of the surface of the pole piece facing the other rotor is the fan-shaped shape, a reduction in maximum torque can be suppressed.

In the present invention, the one rotor may be disposed on the inner peripheral side of the stator. Further, the one rotor may be disposed on the outer peripheral side of the stator.
In either case, eddy current loss can be suppressed and torque transmission efficiency can be improved.

In the present invention, it is preferable to provide a magnetic field reinforcing back yoke made of a magnetic material on the back surface of the rotor of either or both of the two rotors as viewed from the stator.
In this case, the magnetic field of the rotor provided with the back yoke is strengthened, and the transmittable torque increases.

In this invention, the permanent magnet of the one rotor may be magnetized from a direction perpendicular to the rotation axis of the one rotor. Further, the permanent magnet of the one rotor may be magnetized from one direction along a plane perpendicular to the rotation axis of the one rotor. Further, the permanent magnets of the one rotor may be arranged in a Halbach array.
In either case, eddy current loss can be suppressed and torque transmission efficiency can be improved.

  A magnetic gear device according to the present invention includes two rotors each having a plurality of permanent magnets, and a stator having a plurality of pole pieces magnetically positioned between the two rotors and capable of modulating magnetic flux. One rotor of the two rotors faces the stator through a radial gap in a direction perpendicular to the rotation axis of the rotor, and the other of the two rotors rotates. The rotor is opposed to the stator via an axial gap in a direction parallel to the rotation axis of the rotor, and the pole piece is configured by using a dust core. Current loss can be suppressed and high torque transmission efficiency can be realized.

1 is a perspective view of a magnetic gear device according to a first embodiment of the present invention. It is a figure which shows the flow of the magnetic flux of the pole piece in the magnetic gear apparatus. It is a perspective view of the magnetic gear apparatus concerning 2nd Embodiment of this invention. It is a perspective view of the magnetic gear apparatus concerning 3rd Embodiment of this invention. It is a perspective view of the magnetic gear apparatus concerning 4th Embodiment of this invention. It is a perspective view of the magnetic gear apparatus concerning 5th Embodiment of this invention. It is a perspective view of the magnetic gear apparatus concerning the 6th Embodiment of this invention. It is a perspective view of the magnetic gear apparatus concerning the 7th Embodiment of this invention. It is a perspective view of the magnetic gear apparatus concerning the 8th Embodiment of this invention. It is a perspective view of the magnetic gear apparatus concerning the 9th Embodiment of this invention. It is a figure which shows the flow of the magnetic flux of the pole piece in the magnetic gear apparatus. It is a figure which shows the shape of the surface facing the other rotor of the pole piece in the magnetic gear apparatus. It is a figure which shows the different shape of the surface facing the other rotor of a pole piece. It is a perspective view of the magnetic gear apparatus concerning 10th Embodiment of this invention. It is a perspective view of the magnetic gear apparatus concerning 11th Embodiment of this invention. It is a figure which shows the flow of the magnetic flux of the pole piece in the magnetic gear apparatus. It is a perspective view of the magnetic gear apparatus concerning the 12th Embodiment of this invention. It is a perspective view of the magnetic gear apparatus concerning 13th Embodiment of this invention. It is a perspective view of the magnetic gear apparatus concerning 14th Embodiment of this invention. It is a perspective view of the magnetic gear apparatus concerning 15th Embodiment of this invention. It is a top view of an example of one rotor. It is a top view of the other example of one rotor. It is a top view of the other example of one rotor.

An embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows a first embodiment of the present invention. This magnetic gear device includes two rotors 1 and 2 and a stator 3 magnetically interposed between the two rotors 1 and 2. One rotor 1 of the two rotors 1 and 2 faces the stator 3 via a radial gap RG in a direction perpendicular to the rotation axis O1, that is, a radial direction, and the other rotor 2 has its rotation axis. It faces the stator 3 through an axial gap AG in the direction parallel to O2, that is, in the axial direction. The rotation axes O1 and O2 of the two rotors 1 and 2 are located on the same axis.

  In the one rotor 1, a plurality of permanent magnets 1a are arranged in a cylindrical shape around the rotation axis O1. Each permanent magnet 1a is magnetized in the radial direction, for example, as shown in FIG. Two adjacent permanent magnets 1a have opposite magnetic poles. In other words, the N-S arrangement has N poles and S poles alternately arranged. In the illustrated example, the number of permanent magnets 1a is two.

  In FIG. 1, in the other rotor 2, a plurality of permanent magnets 2a are arranged in a cylindrical shape around a rotation axis O2. Each permanent magnet 2a is magnetized in the direction of the rotation axis O2, for example. Two adjacent permanent magnets 2a have opposite magnetic poles. In other words, the N-S arrangement has N poles and S poles alternately arranged. In the illustrated example, the number of permanent magnets 2a is six.

  The stator 3 is composed of a plurality of pole pieces 3a arranged at equal intervals on a circumference centered on the rotation axis O1 of one rotor 1. As for each pole piece 3a, the one end part (upper part of a figure) of an internal peripheral surface opposes one rotor 1, and the end surface (bottom face of a figure) of the other end side opposes the other rotor 2. .

  In the case of this embodiment, the pole piece 3a has an L shape. That is, the inner peripheral surface which is a surface facing one rotor 1 is formed of the same cylindrical surface over the entire axial direction, and the outer peripheral surface which is the back side surface when viewed from one rotor 1 is The diameter of a part (lower end in the figure) on the other rotor 2 side is stepwise larger than the diameter of the other part. The width of the pole piece 3a in the circumferential direction is the same over the entire axial direction. As will be described later, the shape of the pole piece 3a may be other than the above.

  The number of pole pieces 3a is the sum of the number of pole pairs of the two rotors 1 and 2. In this example, one rotor 1 is a two-pole or one-pole pair and the other rotor 2 is a six-pole or three-pole pair, so 1 (pole pair number) +3 (pole-pair number) = 4 (pole pole) The stator 3 has four pole pieces 3a. Even in cases other than the number of pole pairs of the rotors 1 and 2 in this example, the relationship between the number of pole pairs of the rotors 1 and 2 and the number of pole pieces 3a is established.

As described above, the stator 3 faces the one rotor 1 via the radial gap RG and faces the other rotor 2 via the axial gap AG. 2 is magnetically coupled. As a result, the rotation of the rotor on the driving side is transmitted to the rotor on the driven side at a gear ratio according to the number of magnetic poles of both rotors. The rotation direction of the rotor on the driven side is opposite to the rotation direction of the rotor on the driving side. For example, when the other rotor 2 is a rotor on the driving side and one rotor 1 is a rotor on the driven side, one rotor 1 is three times the rotation of the other rotor 2. Rotate in reverse direction at speed. In this case, the magnetic gear device becomes a speed increaser. When the driving side and the driven side are switched, a reduction gear is obtained.

  The pole piece 3a is configured using a dust core. The dust core is an iron core obtained by making a magnetic material into a fine powder, covering the surface with an insulating coating and solidifying it by pressing, and is also called a dust core. Since the dust core has a structure insulated at the powder level, it is characterized by a high effect of reducing eddy currents in all magnetic flux directions.

The reason why a dust core is used for the pole piece 3a will be described.
When one rotor 1 is opposed to the stator 3 via the radial gap RG and the other rotor 2 is opposed to the stator 3 via the axial gap AG, each pole piece 3a of the stator 3 is The direction of the flowing magnetic flux is three-dimensional. As shown in FIG. 2, the direction of the magnetic flux acting between the magnetic poles of one rotor 1 and the other rotor 2 is approximately the direction of the rotation axis O1, O2 of each rotor 1, 2, but one rotation Magnetic flux is generated in the circumferential direction at a portion facing the vicinity of the magnetic pole boundary of the rotor 1 and the other rotor 2. For this reason, when the pole piece 3a is formed of a laminated electromagnetic steel sheet having only a two-dimensional magnetic flux direction suppressing effect, the effect of reducing eddy current loss is weak and torque transmission efficiency is reduced. However, if the pole piece is configured using a dust core, the effect of reducing eddy currents in a three-dimensional magnetic flux direction is high, and therefore, eddy current loss can be suppressed and torque transmission efficiency can be improved.

  In this magnetic gear device, since the two rotors 1 and 2 transmit torque without contact with each other, the merit of the magnetic gear device described in the “Background Art” column is applicable as it is. Further, a partition wall can be sandwiched between both or one of the radial gap RG portion between one rotor 1 and the stator 3 and the axial gap AG portion between the other rotor 2 and the stator 3. Therefore, the two rotors 1 and 2 can be driven in different media. Therefore, this magnetic gear device is suitable for applications such as a pump.

  FIG. 3 shows a second embodiment of the present invention. In the magnetic gear device of FIG. 1, one rotor 1 is arranged on the inner peripheral side of the stator 3, whereas in the magnetic gear device of FIG. 3, one rotor 1 is on the outer peripheral side of the stator 3. Is arranged. Other configurations are the same as those of the magnetic gear device of FIG. Even if one of the rotors 1 is disposed on the inner peripheral side or the outer peripheral side of the stator 3, the effect of reducing the three-dimensional eddy current can be obtained.

  In both the magnetic gear device of FIG. 1 and the magnetic gear device of FIG. 3, the magnitude relationship between one rotor 1 and the other rotor 2 can be arbitrarily determined. For example, even if one rotor 1 is arranged on the inner peripheral side of the stator 3 as in the magnetic gear device of FIG. 1, the shape of the pole piece 3a of the stator 3 can be devised. The diameter of one rotor 1 may be larger than the diameter of the other rotor 2. Further, even if one rotor 1 is arranged on the outer peripheral side of the stator 3 as in the magnetic gear device of FIG. 3, the diameter of one rotor 1 is set to the diameter of the other rotor 2. It may be smaller.

  FIG. 4 shows a third embodiment of the present invention. This magnetic gear device is obtained by adding back yokes 4 and 5 for magnetic field reinforcement to the magnetic gear device of FIG. The back yokes 4 and 5 are made of a magnetic material. The back yoke 4 is provided on the inner peripheral surface of one rotor 1, and the back yoke 5 is provided on the bottom surface of the other rotor 2. The inner peripheral surface of one rotor 1 and the bottom surface of the other rotor 2 are surfaces on the back side when viewed from the stator 3 in the rotors 1 and 2. When the back yokes 4 and 5 are provided, the magnetic fields of the rotors 1 and 2 are strengthened, and the transmittable torque is increased.

FIG. 5 shows a fourth embodiment of the present invention. This magnetic gear device is obtained by adding back yokes 4 and 5 for magnetic field reinforcement to the magnetic gear device of FIG. The back yoke 4 is provided on the outer peripheral surface of one rotor 1, and the back yoke 5 is provided on the bottom surface of the other rotor 2. Also in this case, similarly to the above, the magnetic fields of the rotors 1 and 2 are strengthened, and the transmittable torque is increased.
4 and 5, the back yokes 4 and 5 are provided on both of the two rotors 1 and 2, but the back yoke 4 (5) is provided only on one rotor 1 (2). It is good also as a structure.

  FIG. 6 shows a fifth embodiment of the present invention. In this magnetic gear device, the arrangement of the permanent magnets of the other rotor 2 is changed from the NS arrangement of the magnetic gear device of FIG. 1 to the Halbach arrangement. That is, the permanent magnet 2b magnetized in the direction of the rotation axis O2 and the permanent magnet 2c magnetized in the circumferential direction are alternately arranged on the same circumference. The magnetization directions of the two adjacent permanent magnets 2b are opposite to each other, and the magnetization directions of the two adjacent permanent magnets 2c are opposite to each other. Other configurations are the same as those of the magnetic gear device of FIG.

  Thus, by arranging the arrangement of the permanent magnets 2b, 2c of the other rotor 2 in the Halbach arrangement, the magnetic field of the other rotor 2 is strengthened, the transmittable torque of the magnetic gear device is increased, and the axial gap is increased. Drive transmission is possible even if the AG is widened.

  7 to 9 show sixth to eighth embodiments of the present invention. In these magnetic gear devices, the arrangement of the permanent magnets of the other rotor 2 is changed from the NS arrangement of each magnetic gear device of FIGS. 3, 4, and 5 to the Halbach arrangement in the same manner as described above. is there. Other configurations are the same as those of the magnetic gear devices of FIGS. 3, 4, and 5. Also in this case, the same operation and effect as described above can be obtained.

Hereinafter, embodiments in which the shape of the pole piece 3a is different will be described.
FIG. 10 shows a ninth embodiment of the present invention. The pole piece 3a of this magnetic gear device has a tapered shape in which the outer peripheral surface, which is the surface on the back side when viewed from one rotor 1, is continuously increased in diameter from the upper end of the figure to the vicinity of the lower end of the figure. Is formed. On the inner peripheral surface of the pole piece 3a, a step 12 is provided at the boundary between the portion 10 facing the one rotor 1 and the other portion 11, and the diameter of the portion 10 facing the one rotor 1 is small. The diameter of the other part 11 is large. The shape of the pole piece 3a is such that at least the portion 10 facing the rotor 1 has an axial cross-sectional area as it approaches the other rotor 2, that is, a cross-sectional area of a cross section perpendicular to the rotational axis O1 is continuous. It can be said that it is getting bigger. As for only the other portion 11, the axial cross-sectional area continuously increases as it approaches the other rotor 2.

  When the pole piece 3a has the above shape, as shown in FIG. 11, the flow of magnetic flux in the pole piece 3a becomes smooth, and the leakage magnetic flux generated at a position far from the other rotor 2 in the pole piece 3a is generated. It can be minimized. This was confirmed by testing. By suppressing the leakage magnetic flux, the magnetic flux acting on the other rotor 2 is increased, and the transmission torque and the transmission efficiency are improved.

  As shown in FIG. 12, the magnetic gear device of each embodiment described so far including the magnetic gear device of FIG. 10 has a bottom surface 13 (hatched) that faces the other rotor 2 in the pole piece 3a. The shape of the portion is substantially square. In this way, when the shape of the bottom surface 13 of the pole piece 3a is a substantially square shape, it is the same phenomenon as adding a skew angle when compared to a motor, and it can be expected to suppress cogging torque and torque ripple. The maximum torque decreases.

  As a countermeasure, the shape of the bottom surface 13 of the pole piece 3a is preferably a fan shape shown in FIG. The fan-shaped shape has two concentric arcs 14 and 15 having different radii around the rotation axis O2 of the other rotor 2 and 2 extending radially from the rotation axis O2 of the other rotor 2 in different directions. It is a shape surrounded by radial lines 16 and 16 of the book. In this example, the radii of the two concentric arcs 14 and 15 are the outer diameter and the inner diameter of the other rotor 2, respectively. Thus, the fall of the maximum torque can be suppressed by making the shape of the bottom face 13 of the pole piece 3a into a fan-shaped shape. The optimum angle of the central angle θ formed by the two radial straight lines 16 and 16 depends on the number of poles of the other rotor 2, the axial gap AG (FIG. 10) between the other rotor 2 and the pole piece 3a, and the like. Different. The optimum angle of the center angle θ is obtained by magnetic field analysis or the like.

  Further, in the magnetic gear device of FIG. 10, the axial cross-sectional area of the portion 10 facing the one rotor 1 of the pole piece 3a not only continuously increases as the other rotor 2 approaches, The axial cross-sectional area of the other portion 11 also increases continuously as it approaches the other rotor 2. This is to make the flow of magnetic flux in the pole piece 3a smooth, but depending on the number of pole pairs of one rotor 1 and the other rotor 2, the other portion 11 may have the above shape. There are cases where it is not possible. The other part 11 refers to “a part other than the part directly facing one rotor” in the claims.

  For example, as in the tenth embodiment shown in FIG. 14, a magnetic gear device having a large number of poles of the other rotor 2 has the following problems. That is, if the axial cross-sectional area of the other part 11 of the pole piece 3a increases as it approaches the other rotor 2, the area of the pole piece 3a facing the other rotor 2 becomes too large, There is a possibility that two pole pieces 3a face each other across the N pole and N pole, or the S pole and S pole adjacent in the circumferential direction. Therefore, the pole piece 3a is made smaller in the axial sectional area of the other portion 11 as it approaches the other rotor 2, and the area of the pole piece 3a facing the other rotor 2 is reduced, thereby reducing the pole piece. Avoid straddling 3a.

  In the magnetic gear device of FIG. 14, one rotor 1 has two poles (one pole pair), the other rotor 2 has twelve poles (six pole pairs), and seven pole pieces 3a (one pole pair + 6 poles). This is an example. Generally, as the number of poles of the other rotor 2 increases, the area of the pole piece 3a facing the other rotor 2 needs to be reduced. In the magnetic gear device of FIG. 14, the axial cross-sectional area of the pole piece 3a decreases in a tapered shape as it approaches the other rotor 2, but may decrease in stages.

  In the pole piece 3a of the embodiment shown in FIG. 10, the diameter of the outer peripheral surface is continuously increased from the upper end of the drawing to the vicinity of the lower end of the drawing, but it may be increased stepwise. Also in that case, there is an effect of suppressing the leakage magnetic flux generated in the part far away from the other rotor 2 in the pole piece 3a.

  FIG. 15 shows an eleventh embodiment of the present invention. The pole piece 3a of this magnetic gear device has the same outer diameter from the upper end of the figure to the lower end of the figure. Similar to the embodiment shown in FIG. 10, the inner peripheral surface of the pole piece 3 a has a stepped portion 12 at the boundary between the portion 10 facing the one rotor 1 and the other portion 11. The shape of the pole piece 3a is almost a rectangle.

  When the pole piece 3a has a shape close to a rectangle, as shown in FIG. 16, a leakage magnetic flux is likely to be generated at a position far away from the other rotor 2 in the pole piece 3a. Therefore, the shape of the pole piece 3a close to the rectangle is not so preferable in terms of torque transmission efficiency. However, since the shape is simple, there is an advantage that it is easy to mold and can be easily fixed and positioned with respect to the housing in which the magnetic gear device is accommodated.

  FIG. 17 shows a twelfth embodiment of the present invention. The pole piece 3a of this magnetic gear device has both the outer peripheral surface and the inner peripheral surface having the same diameter from the upper end of the figure to the lower end of the figure, and has a completely rectangular shape. The complete rectangular shape is simpler and easier to mold than the shape close to the rectangle in FIG. The torque transmission efficiency is substantially the same as that of the magnetic gear device of FIG.

  The L-shaped pole piece 3a shown in FIG. 1 has a shape in which the outer diameter of the lower end portion in the figure is stepwise larger than the outer diameter of the other portions, so that the axial cross-sectional area becomes closer to the other rotor 2 It can be said that it is a kind of form that gradually increases. However, if the pole piece 3a is limited to a portion facing the one rotor 1, the axial cross-sectional area does not increase as the other rotor 2 is approached.

  The magnetic gear device of FIG. 1 provided with the L-shaped pole piece 3a having the above-described configuration is the same as the magnetic gear device provided with the pole piece 3a having the tapered outer peripheral surface shown in FIG. 10 and the rectangular shape shown in FIGS. Or it has an intermediate characteristic with the magnetic gear apparatus provided with the pole piece 3a of the shape close | similar to a rectangle. That is, the torque transmission efficiency is superior to that of FIGS. 15 and 17, but is inferior to that of FIG. Further, the ease of molding is superior to that of FIG. 10, but is inferior to that of FIGS. The shape of the pole piece 3a to be used may be determined according to the purpose and application of the magnetic gear device.

  FIG. 18 shows a thirteenth embodiment of the present invention. The pole piece 3a of the magnetic gear device is cut out in a substantially triangular pyramid shape from the outer peripheral surface to the side surface facing the circumferential direction in the upper portion of the figure, so that the axial sectional area gradually increases as the other rotor 2 is approached. It becomes the form which becomes. By forming the pole piece 3a in this way, it is possible to suppress leakage magnetic flux generated at a position far away from the other rotor 2 in the pole piece 3a, and to improve transmission torque and transmission efficiency. Although not shown, combining the technique of notching in a substantially triangular pyramid and the technique of forming the outer peripheral surface in a tapered shape has an effect of improving the transmission torque and transmission efficiency.

  FIG. 19 shows a fourteenth embodiment of the present invention. In this magnetic gear device, the shape of a pole piece 3a that suppresses leakage of magnetic flux is applied to a magnetic gear device in which one rotor 1 is arranged on the outer peripheral side of a stator 3. The pole piece 3a of this magnetic gear device has a tapered shape in which the inner peripheral surface, which is the back side as viewed from one rotor 1, has a diameter that continuously increases from the upper end of the figure to the vicinity of the lower end of the figure. Is formed. As for the outer peripheral surface of the pole piece 3a, the diameter of the lower end part of a figure is larger stepwise than the diameter of another part.

  Similarly to the magnetic gear device of FIG. 10, the shape of the pole piece 3 a also increases in the axial sectional area as it approaches the other rotor 2. For this reason, the leakage magnetic flux which generate | occur | produces in the site | part far away from the other rotor 2 in the pole piece 3a can be suppressed to the minimum, and transmission torque and transmission efficiency improve.

  FIG. 20 shows a fifteenth embodiment of the present invention. This magnetic gear device is obtained by adding back yokes 4 and 5 for magnetic field reinforcement to the magnetic gear device of FIG. The back yoke 4 is provided on the inner peripheral surface of one rotor 1, and the back yoke 5 is provided on the bottom surface of the other rotor 2. By adding the back yokes 4 and 5 to the magnetic gear device having the pole piece 3a having a shape capable of suppressing the leakage magnetic flux, the magnetic fields of the rotors 1 and 2 are further strengthened, and the transmittable torque is increased. To do.

FIGS. 21 to 23 are views of one of the different rotors as seen from the axial direction. The rotor 1 one shown in FIG. 21 is a N-S sequence N and S poles are alternately arranged on a circumference, a La dialkyl magnetization of the permanent magnet 1a is magnetized in the radial direction. The rotor 1 shown in FIG. 22 has an NS arrangement, but is a parallel magnetization in which the permanent magnet 1a is magnetized from one direction on a plane perpendicular to the rotation axis O1. Further, in one rotor 1 shown in FIG. 23, permanent magnets 1b and 1c are arranged in a Halbach array.

  The magnetic gear device of each of the above embodiments shows an example (FIG. 21 or FIG. 22) in which one rotor 1 is an NS array, but one rotor 1 may also be a Halbach array (FIG. 23). good. In that case, the magnetic field of one rotor 1 is strengthened, the transmittable torque of the magnetic gear device is increased, and drive transmission is possible even if the radial gap RG is widened.

  As mentioned above, although the form for implementing this invention based on the Example was demonstrated, embodiment disclosed here is an illustration and restrictive at no points. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

DESCRIPTION OF SYMBOLS 1 ... One rotor 1a, 1b, 1c ... Permanent magnet 2 ... The other rotor 2a, 2b, 2c ... Permanent magnet 3 ... Stator 3a ... Pole piece 4, 5 ... Back yoke 10 ... One rotor and positive Part 11 to the other part (the part other than the part directly facing one rotor)
13: Bottom surface of pole piece (surface facing the other rotor)
14, 15 ... Concentric arc 16 ... Radial straight line AG ... Axial gap O1 ... Rotational axis O2 of one rotor ... Rotational axis RG of the other rotor ... Radial gap

Claims (13)

Two rotors each having a plurality of permanent magnets, and a stator magnetically positioned between the two rotors and having a plurality of pole pieces capable of modulating magnetic flux,
One rotor of the two rotors faces the stator via a radial gap in a direction perpendicular to the rotation axis of the rotor, and the other rotor of the two rotors. Is opposed to the stator through an axial gap in a direction parallel to the rotation axis of the rotor,
A magnetic gear device, wherein the pole piece is configured using a dust core.   2. The magnetic gear device according to claim 1, wherein in the other rotor, the plurality of permanent magnets are arranged at equal intervals on the same circumference so that the directions of magnetic poles of two adjacent permanent magnets are different from each other. Magnetic gear unit.   2. The magnetic gear device according to claim 1, wherein the other rotor has the plurality of permanent magnets arranged in a Halbach array.   4. The magnetic gear device according to claim 1, wherein at least a portion of the pole piece that directly faces the one rotor approaches the one rotor as the pole piece approaches the other rotor. 5. The magnetic gear device in which the cross-sectional area of the cross section perpendicular to the rotation axis is large.   5. The magnetic gear device according to claim 4, wherein at least a portion of the pole piece facing the one rotor is cut off in a cross section perpendicular to the rotation axis of the one rotor as the other rotor approaches. Magnetic gear device with continuously increasing area.   6. The magnetic gear device according to claim 4, wherein a portion of the pole piece other than the portion facing the one rotor is closer to the other rotor, and the rotation axis of the one rotor is increased. Magnetic gear device in which the cross-sectional area of the cross section perpendicular to is small.   7. The magnetic gear device according to claim 1, wherein a shape of a surface of the pole piece facing the other rotor is mutually centered around a rotation axis of the other rotor. A magnetic gear device having a fan-shaped shape surrounded by two concentric arcs having different radii and two straight lines extending radially in different directions from the rotation axis of the other rotor.   The magnetic gear device according to any one of claims 1 to 7, wherein the one rotor is arranged on an inner peripheral side of the stator.   The magnetic gear device according to any one of claims 1 to 7, wherein the one rotor is arranged on an outer peripheral side of the stator.   The magnetic gear device according to any one of claims 1 to 9, wherein a magnetic material is formed on a back surface of the rotor of one or both of the two rotors as viewed from the stator. A magnetic gear device provided with a back yoke for magnetic field enhancement.   11. The magnetic gear device according to claim 1, wherein the permanent magnet of the one rotor is magnetized from a direction perpendicular to a rotation axis of the one rotor. Gear device.   11. The magnetic gear device according to claim 1, wherein the permanent magnet of the one rotor is magnetized from one direction along a plane perpendicular to the rotation axis of the one rotor. Magnetic gear unit.   The magnetic gear device according to any one of claims 1 to 10, wherein the permanent magnets of the one rotor are arranged in a Halbach array.

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