JP7273744B2 - magnetic gear device - Google Patents

Description

The present invention relates to a non-contact power transmission device.

A magnetic gear device is known as one of non-contact power transmission devices. An example of a conventional magnetic gear device is described in Patent Document 1. The magnetic gear device described in Patent Literature 1 is a magnetic reduction device including one stator and two rotors (high-speed rotor and low-speed rotor).

Japanese Patent No. 5858399

One of the technical problems in conventional magnetic gear devices is improvement in cooling performance. The temperature of the stator and rotor of the magnetic gear device rises due to induction heating based on the alternating magnetic field intersecting them. Copper loss (Joule heat) in the coils of the stator also increases the temperature of the stator and the rotor around the stator. When the temperature of the stator and rotor rises in this way, the power performance of the magnetic gear device deteriorates, and bearings included in the magnetic gear device deteriorate.

SUMMARY OF THE INVENTION An object of the present invention is to improve the cooling performance of a magnetic gear device.

The magnetic gear device of the present invention has a stator, a low speed rotor coaxial with the stator surrounding the stator, and a high speed rotor coaxial with the low speed rotor surrounding the low speed rotor. The stator includes a plurality of teeth arranged annularly and a coil wound around each of the teeth. The low-speed rotor includes a plurality of magnetic pieces annularly arranged so as to surround the stator, and a first support member that supports the magnetic pieces. The high-speed rotor includes a plurality of magnets annularly arranged so as to surround the plurality of magnetic pieces, and a second support member that supports the magnets. The first support member is formed with a plurality of communication holes facing the coils of the stator, and the second support member is formed with a plurality of openings facing the communication holes.

In one aspect of the present invention, the low-speed rotor includes fins arranged between two magnetic pieces adjacent in the circumferential direction.

In another aspect of the invention, the first support member includes a base member and a fixing member that face each other, and a plurality of connecting members that connect the base member and the fixing member. Further, the second support member includes a cylindrical peripheral wall portion and a bottom portion that closes one end of the peripheral wall portion. The magnetic piece is arranged between the base member and the fixing member, one end of the magnetic piece is engaged with the base member, and the other end of the magnetic piece is engaged with the fixing member. do. Also, the magnet is fixed to the inner peripheral surface of the peripheral wall portion.

In another aspect of the present invention, the plurality of connecting members are arranged annularly along the circumferential direction of the base member and the fixing member, and two of the connecting members are arranged between two of the connecting members adjacent in the arrangement direction. Magnetic pieces are arranged, and one fin is arranged between the two magnetic pieces.

In another aspect of the present invention, the low-speed rotor is provided at the center of the base member and includes a low-speed rotation shaft inserted through a through hole provided at the center of the stator. The high-speed rotor is provided at the center of the bottom portion and includes a high-speed rotating shaft inserted inside the low-speed rotating shaft.

In another aspect of the present invention, the communication hole is formed in an annular region on the base member located between the low-speed rotation shaft and the magnetic piece in the radial direction. The opening is formed in an annular area on the bottom located radially between the high-speed rotating shaft and the peripheral wall.

In another aspect of the present invention, the low-speed rotor includes projections formed between two of the communication holes adjacent in the circumferential direction. The protrusion protrudes toward the coil provided on the stator and extends along the communication hole.

According to the present invention, a magnetic gear device with high cooling performance is realized.

1 is an exploded view of a magnetic geared motor to which the present invention is applied; FIG. 3 is another exploded view of a magnetic geared motor to which the present invention is applied; FIG. 1 is a perspective view of a magnetic geared motor to which the present invention is applied; FIG. Figure 2 is an exploded view of the low speed rotor shown in Figure 1; Figure 3 is a cross-sectional view along AA shown in Figure 2; Figure 3 is a cross-sectional view along BB shown in Figure 2;

Hereinafter, an example of an embodiment of the magnetic gear device of the present invention will be described in detail with reference to the drawings. As shown in FIGS. 1 and 2, the magnetic gear device according to this embodiment is a magnetic geared motor 1 having a stator 10, a low speed rotor 20, and a high speed rotor 30. FIG. As shown in FIG. 2, the central axes of the stator 10, the low speed rotor 20 and the high speed rotor 30 are on the same straight line. That is, the stator 10, the low speed rotor 20 and the high speed rotor 30 are coaxial. Also, the low speed rotor 20 surrounds the stator 10 and the high speed rotor 30 surrounds the low speed rotor 20 . In other words, the low-speed rotor 20 is fitted inside the high-speed rotor 30 , and the stator 10 is fitted inside the low-speed rotor 20 . In the following description, the direction of the central axes of the stator 10, the low-speed rotor 20, and the high-speed rotor 30 may be called "axial direction", and the direction orthogonal to the axial direction may be called "radial direction". In other words, the horizontal direction of FIG. 2 may be called the "axial direction", and the vertical direction of the paper may be called the "radial direction". Also, the circumferential direction of a virtual circle centered on one point on the central axis of the stator 10, low-speed rotor 20, or high-speed rotor 30 may be called "circumferential direction".

As shown in FIGS. 1 and 2 , the stator 10 includes a plurality of teeth 11 arranged in an annular shape and coils 12 wound around the respective teeth 11 . Specifically, the stator 10 has 18 teeth 11 and coils 12 are wound around each of the 18 teeth 11 . That is, the number of magnetic poles (Ns) of the stator 10 is "18". The 18 teeth 11 and coils 12 are arranged annularly at regular intervals around a through-hole 13 provided in the center of the stator 10 . Also, the teeth 11 and the coils 12 radially extend from the center of the stator 10 . Each tooth 11 is formed of a plurality of laminated silicon steel plates, and each coil 12 is formed of enamel-coated copper wire. The silicon steel plate forming the teeth 11 has a thickness of 0.2 mm. An insulator (not shown) is interposed between the teeth 11 and the coil 12 .

Of the 18 coils 12 provided in the stator 10, 6 are U-phase coils, the other 6 are V-phase coils, and the other 6 are W-phase coils. More specifically, each of the U-phase, V-phase, and W-phase consists of two coil groups each formed of three consecutive coils in the same phase. A V-phase coil group is arranged on one circumferential side of the U-phase coil group, and a W-phase coil group is arranged on the other circumferential side of the U-phase coil group. Also, the two in-phase coil groups are arranged at positions facing each other in the radial direction. Alternating currents 120 degrees out of phase with each other are supplied to the coils 12 of each phase.

As shown in FIGS. 1 and 2, the low-speed rotor 20 is arranged between a plurality of magnetic pieces 21 arranged annularly so as to surround the stator 10 and two adjacent magnetic pieces 21 in the circumferential direction. and a first support member 40 that supports the magnetic pieces 21 and the fins 22 . Specifically, the low-speed rotor 20 includes 34 magnetic pieces 21 and 17 fins 22 arranged at regular intervals in the circumferential direction. That is, the number of magnetic poles (Nl) of the low speed rotor 20 is "34". The magnetic pieces 21 , the fins 22 and the first support member 40 are made of the same or substantially the same silicon steel plate as the silicon steel plate forming the teeth 11 of the stator 10 .

As shown in FIGS. 1 and 4, the first support member 40 includes a base member 41 and a fixing member 42 that face each other in the axial direction, a plurality of connecting members 43 that connect the base member 41 and the fixing member 42, contains. As shown in FIG. 1, the base member 41 is generally disc-shaped and the fixing member 42 is generally ring-shaped.

As shown in FIGS. 1 and 4, 34 magnetic pieces 21 and 17 fins 22 are arranged between a base member 41 and a fixed member 42 facing each other. In other words, the base member 41 and the fixing member 42 sandwich the plurality of magnetic pieces 21 and the fins 22 . At least one end of the magnetic piece 21 is engaged with the base member 41 , and at least the other end of the magnetic piece 21 is engaged with the fixing member 42 . As shown in FIG. 4, on one surface of the base member 41 facing the fixing member 42, a plurality of recesses 41a with which the ends of the magnetic pieces 21 can be engaged are formed at regular intervals in the circumferential direction. Also, on one surface of the fixing member 42 facing the base member 41, a plurality of recesses 42a with which the ends of the magnetic pieces 21 can be engaged are formed at regular intervals in the circumferential direction (the recesses 41a formed in the base member 41 are formed at the same intervals). One end of each magnetic piece 21 is engaged with the recess 41 a of the base member 41 , and the other end of each magnetic piece 21 is engaged with the recess 42 a of the fixing member 42 . are doing.

As shown in FIGS. 1 and 4 , the connecting member 43 axially penetrates the base member 41 and is coupled to the fixed member 42 . Specifically, a male screw is formed at the tip of each connecting member 43 . On the other hand, the fixing member 42 is provided with a threaded hole having a female thread. The tip of the connecting member 43 passing through the base member 41 is screwed into a screw hole provided in the fixing member 42 . Therefore, when each connecting member 43 is tightened, a force acts to bring the base member 41 and the fixing member 42 closer to each other. As a result, the magnetic pieces 21 and the fins 22 arranged between the base member 41 and the fixed member 42 are sandwiched between the base member 41 and the fixed member 42 .

As shown in FIG. 5, the 17 connecting members 43 are annularly arranged at regular intervals in the circumferential direction. Two magnetic pieces 21 are arranged between two connecting members 43 adjacent in the arrangement direction, and one fin 22 is arranged between the two magnetic pieces 21 . For example, two magnetic pieces 21a and 21b are arranged between a connecting member 43a and a connecting member 43b adjacent to the connecting member 43a shown in FIG. One fin 22a is arranged between 21a and 21b. Further, another two magnetic pieces 21c and 21d are arranged between the connecting member 43b and the connecting member 43c adjacent to the connecting member 43b, and the magnetic pieces 21c and 21d are arranged between the two magnetic pieces 21c and 21d. is arranged with another fin 22b. In other words, the connecting member 43 is always arranged on one side of each magnetic piece 21 . For example, the fin a is arranged between the magnetic piece 21a and the magnetic piece 21b, and the connecting member 43 for supporting the load is not arranged. However, the connecting member 43a is arranged on the left side of the magnetic piece 21a, and the connecting member 43b is arranged on the right side of the magnetic piece 21b. This relationship is the same for the magnetic pieces 21c and 21d on both sides of the fin 22b, and is the same for the magnetic pieces 21 on both sides of any other fin 22. FIG. As a result, a space (gap) for arranging the plurality of fins 22 is secured in the low speed rotor 20, and the load applied to the low speed rotor 20 is evenly distributed.

As shown in FIGS. 1 and 2, the low speed rotor 20 has a low speed rotating shaft 23 . The low-speed rotating shaft 23 is provided at the center of the first support member 40 . Specifically, the low speed rotation shaft 23 is formed by a cylindrical member fixed to the center of the base member 41 . That is, the low-speed rotating shaft 23 is hollow. As shown in FIG. 3 , a low-speed rotating shaft 23 provided in the low-speed rotor 20 is inserted through a through-hole 13 ( FIG. 1 ) provided in the center of the stator 10 and passes through the stator 10 . A low-speed rotary shaft 23 inserted through the through hole 13 of the stator 10 is rotatably supported with respect to the stator 10 by bearings 24a and 24b shown in FIG.

Refer to FIG. 3 again. A rod 25 having a smaller diameter than the low speed rotation shaft 23 and being coaxial with the low speed rotation shaft 23 is fixed to the end of the low speed rotation shaft 23 protruding from the stator 10 . That is, the low-speed rotating shaft 23 and the rod 25 rotate integrally. A low-speed rotating shaft 23 including a rod 25 is the output shaft of the magnetic geared motor 1 according to this embodiment.

As shown in FIG. 1 , a plurality of communication holes 44 facing the coils 12 of the stator 10 are formed in the first support member 40 of the low-speed rotor 20 . Specifically, a plurality of communication holes 44 are formed in predetermined regions on the base member 41 of the first support member 40 . Please refer to FIG. A plurality of communication holes 44 are formed at regular intervals in an annular region on the base member 41 located between the low-speed rotation shaft 23 and the magnetic piece 21 in the radial direction. The plurality of communication holes 44 are arranged in a ring and extend radially from the center of the base member 41 . Furthermore, projections 45 are formed between two communicating holes 44 adjacent in the circumferential direction. That is, in the annular region, the communication holes 44 and the protrusions 45 are alternately formed along the circumferential direction.

As shown in FIG. 1 , each protrusion 45 axially protrudes toward the coil 12 of the stator 10 and extends radially along the communication hole 44 . As shown in FIG. 5, the radial dimension (length) of the communication hole 44 and the projection 45 are substantially the same. In addition, the dimension (width) in the circumferential direction of the communication hole 44 and the projection 45 are also substantially the same. However, while the width of the projection 45 is constant, the width of the communication hole 44 gradually increases from the radially inner side to the outer side.

As shown in FIGS. 1 to 3, the high-speed rotor 30 has a plurality of magnets (permanent magnets) 31 arranged annularly so as to surround the plurality of magnetic pieces 21 of the low-speed rotor 20, and supports the magnets 31. A second support member 50 is provided. Specifically, the high-speed rotor 30 includes 16 magnets 31 arranged at regular intervals in the circumferential direction. That is, the number of magnetic poles (Nh) of the high-speed rotor 30 is "16".

The second support member 50 included in the high-speed rotor 30 includes a cylindrical peripheral wall portion 51 and a bottom portion 52 closing one end of the peripheral wall portion 51 . However, the peripheral wall portion 51 and the bottom portion 52 are integrally formed of carbon steel. As shown in FIGS. 1 and 2, 16 magnets 31 are fixed to the inner peripheral surface of the peripheral wall portion 51 . The 16 magnets 31 are arranged so that the N poles and S poles are alternately arranged in the circumferential direction.

As shown in FIGS. 1 and 2, the high speed rotor 30 has a high speed rotating shaft 32 . This high-speed rotating shaft 32 is provided at the center of the second support member 50 . A high-speed rotating shaft 32 of the high-speed rotor 30 is inserted inside a hollow low-speed rotating shaft 23 of the low-speed rotor 20 . The high-speed rotary shaft 32 inserted through the low-speed rotary shaft 23 is rotatably supported with respect to the low-speed rotor 20 including the low-speed rotary shaft 23 by bearings 33a and 33b.

As shown in FIGS. 1 and 6, the second support member 50 provided in the high-speed rotor 30 is formed with a plurality of openings 53 facing the communication holes 44 (FIG. 5) provided in the low-speed rotor 20. ing. Specifically, 12 openings 53 are formed in predetermined regions on the bottom 52 of the second support member 50 . Each opening 53 is a round hole penetrating through the bottom portion 52 and is formed at regular intervals in an annular region on the bottom portion 52 located between the high-speed rotating shaft 32 and the peripheral wall portion 51 in the radial direction.

Refer to FIG. 1 again. In the magnetic geared motor 1 having the structure described above, when alternating current is supplied to the coils 12 of the stator 10, the low-speed rotor 20 and the high-speed rotor 30 rotate. At the same time, the temperatures of the stator 10, the low-speed rotor 20, and the high-speed rotor 30 rise due to induction heating based on the alternating magnetic field and copper loss (Joule heat) of the coil 12. FIG. In particular, the temperature of the low speed rotor 20 located between the stator 10 and the high speed rotor 30 increases.

However, in the magnetic geared motor 1 according to this embodiment, the first support member 40 of the low-speed rotor 20 is provided with a plurality of communication holes 44 facing the coils 12 of the stator 10 . A plurality of openings 53 facing the communication holes 44 are provided in the second support member 50 of the high-speed rotor 30 . Therefore, heat generated from the stator 10 and the low-speed rotor 20 is discharged outside the high-speed rotor 30 through the communicating holes 44 and the openings 53 . That is, the magnetic geared motor 1 is cooled by natural air cooling.

Furthermore, the first support member 40 of the low-speed rotor 20 is provided with a plurality of protrusions 45 in addition to the communication holes 44 . In other words, the surface area of the first support member 40 is enlarged as compared with the case where the projections 45 are not provided. As a result, heat dissipation from the low-speed rotor 20 including the first support member 40 is promoted. In other words, the plurality of protrusions 45 formed on the first support member 40 function as heat sinks that enhance the cooling performance of the magnetic geared motor 1 including the low speed rotor 20 .

In addition, in the magnetic geared motor 1 according to this embodiment, the low speed rotor 20 is provided with a plurality of fins 22 . Therefore, when the low-speed rotor 20 rotates, an air current is generated inside the magnetic geared motor 1 . As a result, heat dissipation from the stator 10 and the low-speed rotor 20 is further promoted. Also, cooling air is supplied to the stator 10 and the like, and these are cooled by forced air cooling. The fins 22 integrated with the first support member 40 also contribute to increasing the surface area of the first support member 40 .

このとき、回転速度比（Ｇｒ）が－（マイナス）となれば、低速ロータ２０は高速ロータ３０に対して反対方向に回転し、＋（プラス）となれば、低速ロータ２０は高速ロータ３０と同一方向に回転する。 As described above, when alternating current is supplied to the coils 12 of the stator 10, the low speed rotor 20 and the high speed rotor 30 rotate. At this time, a predetermined speed difference occurs between the rotational speeds of the low-speed rotor 20 and the high-speed rotor 30 . The rotation speed ratio (Gr) between the low-speed rotor 20 and the high-speed rotor 30 is obtained by the following formula, on the assumption that the number of stator poles (Ns) = the number of low-speed rotor poles (Nl) ± the number of high-speed rotor poles (Nh) holds. represented by

At this time, if the rotation speed ratio (Gr) becomes - (minus), the low speed rotor 20 rotates in the opposite direction to the high speed rotor 30, and if it becomes + (plus), the low speed rotor 20 rotates with the high speed rotor 30. Rotate in the same direction.

As described above, the number of stator magnetic poles (Ns), the number of low-speed rotor magnetic poles (Nl), and the number of high-speed rotor magnetic poles (Nh) in the magnetic geared motor 1 according to this embodiment are as follows.
Number of stator poles (Ns) = 18
Number of low-speed rotor magnetic poles (Nl) = 34
Number of high-speed rotor magnetic poles (Nh) = 16
Therefore, the rotation speed ratio (Gr) between the low-speed rotor 20 and the high-speed rotor 30 in the magnetic geared motor 1 according to this embodiment is +2.125. In other words, the reduction ratio of the magnetic geared motor 1 is +2.125. Therefore, the low speed rotor 20 rotates in the same direction as the high speed rotor 30 .

The present invention is not limited to the above embodiments, and can be modified in various ways without departing from the scope of the invention. For example, the low-speed rotor 20 in the above embodiment was provided with the communication holes 44 , the projections 45 and the fins 22 . However, the projections 45 and the fins 22 can be omitted. In other words, even if only the communication hole 44 is provided in the low speed rotor 20, the cooling performance is sufficiently improved compared to the case where the communication hole 44 is not provided in the low speed rotor 20.

The number, shape, size, arrangement, etc. of the fins 22, the connecting members 43, the communication holes 44, the protrusions 45 and the openings 53 in the above embodiment can be changed as appropriate.

1 Magnetic geared motor 10 Stator 11 Teeth 12 Coil 13 Through hole 20 Low speed rotors 21, 21a, 21b, 21c Magnetic pieces 22, 22a, 22b Fins 23 Low speed rotating shafts 24a, 24b Bearing 25 Rod 30 High speed rotor 31 Magnet 32 High speed rotation Shafts 33a, 33b Bearing 40 First support member 41 Base members 41a, 42a Recess 42 Fixing members 43, 43a, 43b, 43c Connecting member 44 Communication hole 45 Projection 50 Second support member 51 Peripheral wall 52 Bottom 53 Opening

Claims (7)

A magnetic gear device comprising a stator, a low-speed rotor coaxial with the stator surrounding the stator, and a high-speed rotor surrounding the low-speed rotor coaxial with the low-speed rotor,
The stator includes a plurality of teeth arranged in an annular shape and a coil wound around each of the teeth,
The low-speed rotor includes a plurality of magnetic pieces arranged annularly so as to surround the stator, and a first support member that supports the magnetic pieces,
The high-speed rotor includes a plurality of magnets arranged in a ring so as to surround the plurality of magnetic pieces, and a second support member that supports the magnets,
The first support member is formed with a plurality of communication holes facing the coils of the stator,
A magnetic gear device, wherein a plurality of openings facing the communication holes are formed in the second support member. In the magnetic gear device according to claim 1,
A magnetic gear device, wherein the low-speed rotor includes fins arranged between two magnetic pieces adjacent in the circumferential direction. In the magnetic gear device according to claim 2,
The first support member includes a base member and a fixing member that face each other, and a plurality of connecting members that connect the base member and the fixing member,
The second support member includes a cylindrical peripheral wall portion and a bottom portion that closes one end of the peripheral wall portion,
the magnetic piece is disposed between the base member and the fixed member, one end of the magnetic piece engages the base member, the other end of the magnetic piece engages the fixed member;
The magnetic gear device, wherein the magnet is fixed to the inner peripheral surface of the peripheral wall. the plurality of connecting members are annularly arranged along the circumferential direction of the base member and the fixing member;
4. The magnet according to claim 3, wherein two said magnetic pieces are arranged between two said connecting members adjacent in the arrangement direction, and one said fin is arranged between said two said magnetic pieces. gear device. In the magnetic gear device according to claim 3 or 4,
The low-speed rotor is provided at the center of the base member and includes a low-speed rotation shaft inserted through a through hole provided at the center of the stator,
A magnetic gear device, wherein the high-speed rotor is provided at the center of the bottom portion and includes a high-speed rotation shaft inserted inside the low-speed rotation shaft. the communication hole is formed in an annular region on the base member located between the low-speed rotation shaft and the magnetic piece in the radial direction;
6. The magnetic gear device according to claim 5, wherein said opening is formed in an annular region on said bottom located radially between said high-speed rotating shaft and said peripheral wall. In the magnetic gear device according to any one of claims 1 to 6,
The low-speed rotor includes a projection formed between two of the communication holes adjacent in the circumferential direction,
The magnetic gear device, wherein the protrusion protrudes toward the coil provided on the stator and extends along the communication hole.

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