Motor rotor and rotating machine

Abstract

To provide a motor rotor and a rotating machine for improving a torque transmission performance between a shaft and a bonded magnet.SOLUTION: A motor rotor 2 includes: a shaft 10; a first ring portion 11 and a second ring portion 12 each protruding radially outward from an outer circumferential surface of the shaft 10; a cylindrical bonded magnet 13 covering the outer circumferential surface of the shaft 10 between the first ring portion 11 and the second ring portion 12; and a screw 21 provided on the first ring portion 11, protruding from a first inner surface 11c of the first ring portion 11, and engaging with the bonded magnet 13.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a motor rotor and a rotary machine including a motor rotor. [Background technology]

[0002] For example, there is a motor rotor equipped with a bonded magnet. In such a motor rotor, centrifugal force can cause the bonded magnet to float, and differences in linear expansion can cause gaps to form between the bonded magnet and the member to which the bonded magnet is attached. When such floating or gaps occur, the torque transmission performance between the bonded magnet and the member to which the bonded magnet is attached decreases. For this reason, for example, Patent Document 1 describes a configuration for firmly fixing the bonded magnet to the yoke. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 6-178477 Summary of the Invention [Problem to be solved by the invention]

[0004] There is a motor rotor in which a bonded magnet is provided so as to cover the outer peripheral surface of a shaft. In such a motor rotor, it is required to improve the torque transmission performance between the shaft and the bonded magnet. Therefore, this disclosure describes a motor rotor and a rotating machine that can improve the torque transmission performance between the shaft and the bonded magnet. [Means for solving the problem]

[0005] A motor rotor according to one embodiment of the present disclosure comprises a shaft rotatable around a rotation axis, a first ring portion and a second ring portion each protruding radially outward from an outer circumferential surface of the shaft and arranged at a predetermined distance from each other in the direction of the rotation axis, a cylindrical bonded magnet covering the outer circumferential surface of the shaft between the first ring portion and the second ring portion, and a convex portion provided on the first ring portion protruding from a surface of the first ring portion facing the second ring portion and engaging with the bonded magnet.

[0006] In this motor rotor, the protrusion on the first ring engages with the bonded magnet. In other words, torque can be transmitted between the first ring and the bonded magnet via the protrusion that is integrated with the first ring. This allows the motor rotor to improve the torque transmission performance between the shaft on which the first ring is provided and the bonded magnet.

[0007] In the above motor rotor, the protrusions and the bonded magnets may be bonded to each other. In this case, the motor rotor can more firmly connect the protrusions and the bonded magnets. This allows the motor rotor to further improve the torque transmission performance between the shaft and the bonded magnets.

[0008] In the above motor rotor, the first ring portion may be provided with a screw hole extending along the direction of the rotation axis, and the protrusion may be formed by a screw attached to the screw hole. In this case, the motor rotor can easily form the protrusion that engages with the bonded magnet by using the screw.

[0009] In the motor rotor described above, the protrusion may be formed of a metal screw attached to the first ring portion and the second ring portion so as to connect the first ring portion and the second ring portion. In this case, the screw engages with the bonded magnet over the entire area of ​​the bonded magnet in the direction of the rotation axis. This allows the motor rotor to further improve the torque transmission performance between the shaft and the bonded magnet.

[0010] Here, by adjusting the circumferential magnetic flux distribution in the bonded magnet, the characteristics of a rotating machine equipped with a motor rotor can be changed. As described above, the screw is made of metal. Furthermore, the screw is provided over the entire area of ​​the bonded magnet in the direction of the rotation axis. This allows the screw to change the magnetic flux distribution in the bonded magnet over the entire area in the direction of the rotation axis. Therefore, the motor rotor can change the circumferential magnetic flux distribution in the bonded magnet by using the screw, and the characteristics of the rotating machine can be changed.

[0011] A rotary machine according to another aspect of the present disclosure includes the motor rotor described above and a stator arranged to surround the motor rotor. In this case, the rotary machine can improve the torque transmission performance between the shaft provided with the first ring portion and the bonded magnet, similarly to the motor rotor described above. Effect of the Invention

[0012] According to various aspects of the present disclosure, it is possible to improve the torque transmission performance between the shaft and the bonded magnet. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a cross-sectional view showing a schematic configuration of a rotating machine according to an embodiment. [Diagram 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Diagram 3] FIG. 3 is a cross-sectional view showing a schematic configuration of a rotating machine according to a second modified example. [Figure 4] FIG. 4 is a cross-sectional view showing a schematic configuration of a rotating machine according to a third modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In each drawing, the same or corresponding elements are denoted by the same reference numerals, and duplicated explanations will be omitted.

[0015] A rotating machine (electric motor) 1 shown in Fig. 1 functions as a driving source for various electric motors. The rotating machine 1 includes a motor rotor 2 and a stator 3 arranged to surround the motor rotor 2. The motor rotor 2 includes a shaft 10 that can rotate around a rotation axis L, and a bonded magnet 13 provided on the outer circumferential surface of the shaft 10. In the following description, the circumferential direction refers to a direction along a ring centered on the rotation axis L, and the radial direction refers to a direction perpendicular to the rotation axis L.

[0016] The stator 3 includes a core 30 disposed to surround the shaft 10, and a coil 31 formed by winding a conductor around the core 30. The core 30 has a cylindrical shape with the rotation axis L as its central axis. The motor rotor 2 is disposed inside the core 30. The coil 31 faces the motor rotor 2 in the radial direction. When an AC current is supplied to the coil 31 of the stator 3 through the conductor, the stator 3 generates a rotating magnetic field inside the core 30. This rotating magnetic field generates a torque in the motor rotor 2. As a result, the motor rotor 2 rotates around the rotation axis L.

[0017] The motor rotor 2 will be described in detail. In addition to the shaft 10 and bonded magnet 13 described above, the motor rotor 2 further includes a first ring portion 11, a second ring portion 12, an armor ring 14, a screw 21 (convex portion), and a screw 22. The first ring portion 11 and the second ring portion 12 each protrude radially outward from the outer circumferential surface of the shaft 10. The first ring portion 11 and the second ring portion 12 are provided at a predetermined interval from each other in the direction of the rotation axis L. Note that the shaft 10, the first ring portion 11, and the second ring portion 12 may be separate from each other, or may be formed as one body.

[0018] The bonded magnet 13 is provided between the first ring portion 11 and the second ring portion 12. The bonded magnet 13 has a cylindrical shape that covers the outer peripheral surface of the shaft 10. The armor ring 14 has a cylindrical shape that covers the outer peripheral surface of the bonded magnet 13. In this embodiment, the armor ring 14 is located between the first ring portion 11 and the second ring portion 12. The armor ring 14 may be made of, for example, a non-magnetic material with high electrical resistance. As an example, the armor ring 14 may be made of carbon fiber reinforced plastic (CFRP).

[0019] The screw 21 is provided in the first ring portion 11. Here, providing the screw 21 in the first ring portion 11 means that the screw 21 is attached to the first ring portion 11. The first ring portion 11 is provided with a screw hole 11a extending (passing through) along the direction of the rotation axis L. The screw 21 is attached to the first ring portion 11 by being inserted into the screw hole 11a and engaging with the threads of the screw hole 11a.

[0020] Here, the surface of the outer surface of the first ring portion 11 facing the second ring portion 12 is referred to as the first inner surface 11c. In other words, the first inner surface 11c is the surface of the first ring portion 11 facing the second ring portion 12. The surface of the outer surface of the first ring portion 11 opposite to the first inner surface 11c is referred to as the first outer surface 11d. The screw 21 is attached to the first ring portion 11 so that the head of the screw 21 is located on the first outer surface 11d side and the tip of the screw 21 is located on the first inner surface 11c side. As shown in FIG. 2, in this embodiment, four screws 21 are provided as an example. The four screws 21 are provided at equal intervals from each other along the circumferential direction centered on the rotation axis L.

[0021] The tip of the screw 21 protrudes from the first inner surface 11c. The tip of the screw 21 is embedded in the bond magnet 13 and engages with the bond magnet 13. The tip of the screw 21 and the bond magnet 13 are bonded to each other. In this manner, the motor rotor 2 is provided with a protrusion that is provided on the first ring portion 11 and protrudes from the first inner surface 11c of the first ring portion 11 to engage with the bond magnet 13. This protrusion is formed by the screw 21 attached to the screw hole 11a of the first ring portion 11.

[0022] The screw 22 is provided in the second ring portion 12. Here, providing the screw 22 in the second ring portion 12 means that the screw 22 is attached to the second ring portion 12. The second ring portion 12 is provided with a screw hole 12a extending (passing through) along the direction of the rotation axis L. The screw 22 is attached to the second ring portion 12 by being inserted into the screw hole 12a and engaging with the thread of the screw hole 12a.

[0023] Here, the surface of the outer surface of the second ring portion 12 that faces the first ring portion 11 is referred to as the second inner surface 12c. In other words, the second inner surface 12c is the surface of the second ring portion 12 that faces the first ring portion 11. The surface of the outer surface of the second ring portion 12 opposite the second inner surface 12c is referred to as the second outer surface 12d. The screw 22 is attached to the second ring portion 12 so that the head of the screw 22 is located on the second outer surface 12d side and the tip of the screw 22 is located on the second inner surface 12c side. There are four screws 22, similar to the screws 21.

[0024] The tip of the screw 22 protrudes from the second inner surface 12c. The tip of the screw 22 is embedded in the bonded magnet 13 and engages with the bonded magnet 13. The tip of the screw 22 and the bonded magnet 13 are bonded to each other. In this manner, the motor rotor 2 is provided with a protrusion that is provided on the second ring portion 12 and protrudes from the second inner surface 12c of the second ring portion 12 to engage with the bonded magnet 13. This protrusion is constituted by the screw 22 attached to the screw hole 12a of the second ring portion 12.

[0025] Next, an example of a method for mounting the bonded magnet 13 around the shaft 10 will be described. For example, the bonded magnet 13 may be provided around the shaft 10 by injection molding. In this case, the screws 21 and 22 are attached to the first ring portion 11 and the second ring portion 12 in advance, respectively. In addition, the armor ring 14 is placed between the first ring portion 11 and the second ring portion 12. In this state, for example, as shown in FIG. 2, a molten bonded magnet is injected between the first ring portion 11 and the second ring portion 12 through a hole 11b provided in the first ring portion 11 to form the cylindrical bonded magnet 13. The second ring portion 12 may also be provided with a hole used for injection molding.

[0026] It is also possible to use the hole used for injection molding as a hole for inserting the screw 22. In this case, after the bond magnet is injected, the screw 22 is fitted into the hole used for injection molding and engaged with the bond magnet 13. In this case, the tip of the screw 22 fitted into the hole used for injection molding and the bond magnet 13 are not in a state of being adhered to each other. Therefore, when the hole used for injection molding is used as a hole for inserting the screw 22, there will be a mixture of screws 22 that engage with the bond magnet 13 and are adhered to each other, and screws 22 that engage with the bond magnet 13 but are not adhered to the bond magnet 13.

[0027] As a result, when bond magnet 13 hardens, the tips of screws 21 and 22 are embedded in bond magnet 13. Furthermore, the tips of screws 21 and 22 and bond magnet 13 are bonded to each other.

[0028] As described above, in the motor rotor 2, the screw 21 provided on the first ring portion 11 and the screw 21 provided on the second ring portion 12 engage with the bonded magnet 13. In other words, torque can be transmitted between the first ring portion 11 and the second ring portion 12 and the bonded magnet 13 via the screw 21 integrated with the first ring portion 11 and the screw 22 integrated with the second ring portion 12. This enables the motor rotor 2 and the rotating machine 1 to improve the torque transmission performance between the shaft 10 provided with the first ring portion 11 and the second ring portion 12 and the bonded magnet 13.

[0029] The tips of the screws 21 and 22 and the bonded magnet 13 are bonded to each other. In this case, the motor rotor 2 can more firmly connect the screws 21 and 22 and the bonded magnet 13. This allows the motor rotor 2 to further improve the torque transmission performance between the shaft 10 and the bonded magnet 13.

[0030] A screw 21 attached to the screw hole 11a of the first ring portion 11 engages with the bonded magnet 13. The screw 21 functions as a convex portion protruding from the first inner surface 11c of the first ring portion 11. Also, a screw 22 attached to the screw hole 12a of the second ring portion 12 engages with the bonded magnet 13. The screw 22 functions as a convex portion protruding from the second inner surface 12c of the second ring portion 12. In this way, by using the screws 21 and 22, the motor rotor 2 can easily form a convex portion that engages with the bonded magnet 13.

[0031] The screws 21 and 22 that engage with the bonded magnet 13 are separate from the first ring portion 11, the second ring portion 12, and the bonded magnet 13. For this reason, the motor rotor 2 can use the screws 21 and 22 that are made of a high-strength material that has high torque transmission performance.

[0032] Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment. For example, the convex portion that engages with the bonded magnet 13 is not limited to being composed of the screws 21 and 22. Below, modified examples in which the configuration of the convex portion is different from that of the rotating machine 1 according to the embodiment will be described. First, a first modified example will be described. In the first modified example, for example, a pin may be used instead of the screw 21. This pin is attached to the first ring portion 11 by being inserted into a hole provided in the first ring portion 11. This pin may be attached to the first ring portion 11 by being pressed into a hole provided in the first ring portion 11. The pin is provided in the first ring portion 11 and functions as a convex portion that protrudes from the first inner surface 11c of the first ring portion 11 and engages with the bonded magnet 13. Similarly, a pin may be used instead of the screw 22. Even when a pin is used, the motor rotor (rotating machine) can improve the torque transmission performance between the shaft and the bonded magnet.

[0033] Next, a second modified example will be described. As shown in Fig. 3, a rotating machine 1A according to the second modified example includes a motor rotor 2A and a stator 3. Note that Fig. 3 and Fig. 4 described below show only a portion on one side with respect to the rotation axis L. The motor rotor 2A includes a first ring portion 11A, a second ring portion 12A, a bonded magnet 13, an armor ring 14, a first convex portion 23, and a second convex portion 24. The first ring portion 11A and the second ring portion 12A are provided at a predetermined interval from each other in the direction of the rotation axis L.

[0034] The first ring portion 11A protrudes radially outward from the outer circumferential surface of the shaft 10. The first convex portion 23 is provided on the first inner surface 11c of the first ring portion 11A. The first convex portion 23 protrudes from the first inner surface 11c toward the second ring portion 12A. The first ring portion 11A and the first convex portion 23 are integrally formed. The first convex portion 23 engages with the bond magnet 13. The first convex portion 23 and the bond magnet 13 are bonded to each other. As with the screw 21 according to the embodiment, four first convex portions 23 are provided, for example.

[0035] The second ring portion 12A protrudes radially outward from the outer circumferential surface of the shaft 10. The second protrusions 24 are provided on the second inner surface 12c of the second ring portion 12A. The second protrusions 24 protrude from the second inner surface 12c toward the first ring portion 11A. The second ring portion 12A and the second protrusions 24 are integrally formed. The second protrusions 24 engage with the bonded magnet 13. The second protrusions 24 and the bonded magnet 13 are bonded to each other. As with the screw 22 according to the embodiment, four second protrusions 24 are provided, for example.

[0036] In this way, the first convex portion 23 and the second convex portion 24 are formed integrally with the first ring portion 11A and the second ring portion 12A, respectively. Even in this case, the motor rotor 2A and the rotating machine 1A can achieve the same effects as the motor rotor 2 and the rotating machine 1 according to the embodiment.

[0037] Next, a third modified example will be described. As shown in Fig. 4, a rotating machine 1B according to the third modified example includes a motor rotor 2B and a stator 3. The motor rotor 2B includes a first ring portion 11B, a second ring portion 12B, a bonded magnet 13, an armor ring 14, a bolt (screw, convex portion) 25, and a nut 26.

[0038] The first ring portion 11B and the second ring portion 12B are provided at a predetermined interval from each other in the direction of the rotation axis L. The first ring portion 11B is provided with a through hole 11e extending along the direction of the rotation axis L. The second ring portion 12B is provided with a through hole 12e extending along the direction of the rotation axis L.

[0039] The bolt 25 is made of metal. The bolt 25 is inserted into the through hole 11e of the first ring portion 11B and the through hole 12e of the second ring portion 12B. Here, the head of the bolt 25 is located on the first outer surface 11d side of the first ring portion 11B. The tip portion of the bolt 25 is located on the second outer surface 12d side of the second ring portion 12B. Note that the bolt 25 may be threaded on the entire shaft portion, or may be threaded only on the tip portion to which the nut 26 is attached.

[0040] A nut 26 is attached to the tip of the bolt 25. The bolt 25 is attached to the first ring portion 11B and the second ring portion 12B by tightening the nut 26. In other words, the bolt 25 is attached to the first ring portion 11B and the second ring portion 12B by sandwiching the first ring portion 11B and the second ring portion 12B between the head of the bolt 25 and the nut 26.

[0041] The bolts 25 and the nuts 26 may slightly deflect the first ring portion 11B and / or the second ring portion 12B when sandwiching the first ring portion 11B and the second ring portion 12B. The bolts 25 and the nuts 26 may sandwich and hold the armor ring 14 between the first ring portion 11B and the second ring portion 12B.

[0042] As an example, four bolts 25 are provided, similar to the screws 21 according to the embodiment. The bolts 25 penetrate the bonded magnet 13 in the direction of the rotation axis L. The bolts 25 and the bonded magnet 13 are bonded to each other. In this manner, the bolts 25 are provided on the first ring portion 11B and the second ring portion 12B. More specifically, the bolts 25 are attached to the first ring portion 11B and the second ring portion 12B so as to connect the first ring portion 11B and the second ring portion 12B. The bolts 25 function as a protrusion that protrudes from the first inner surface 11c of the first ring portion 11B and engages with the bonded magnet 13.

[0043] In this way, the bolt 25 engages with the bonded magnet 13 over the entire area of ​​the bonded magnet 13 in the direction of the rotation axis L. This allows the motor rotor 2B and the rotating machine 1B to further improve the torque transmission performance between the shaft 10 and the bonded magnet 13.

[0044] Here, by adjusting the circumferential magnetic flux distribution in bonded magnet 13, it is possible to change the characteristics of rotating machine 1B equipped with motor rotor 2B. As described above, bolt 25 is made of metal. Also, bolt 25 is provided over the entire area of ​​bonded magnet 13 in the direction of rotation axis L. This allows bolt 25 to change the magnetic flux distribution over the entire area of ​​bonded magnet 13 in the direction of rotation axis L. Therefore, motor rotor 2B can change the circumferential magnetic flux distribution in bonded magnet 13 by bolt 25, and can change the characteristics of rotating machine 1B.

[0045] In the third modified example, the nut 26 does not necessarily have to be provided. In this case, a screw thread is provided in the through hole 12e of the second ring portion 12B. Then, the bolt 25 may be engaged with the screw thread provided in the through hole 12e.

[0046] The following is a summary of the present disclosure. [1] A shaft rotatable around a rotation axis; a first ring portion and a second ring portion each protruding radially outward from an outer circumferential surface of the shaft and provided at a predetermined interval from each other in the direction of the rotation axis; a cylindrical bonded magnet covering an outer circumferential surface of the shaft between the first ring portion and the second ring portion; a protrusion provided on the first ring portion, protruding from a surface of the first ring portion facing the second ring portion, and engaging with the bond magnet; A motor rotor comprising: [2] The motor rotor according to [1] above, wherein the protrusion and the bonded magnet are bonded to each other. [3] The first ring portion is provided with a screw hole extending along the rotation axis direction, The motor rotor according to the above [1] or [2], wherein the convex portion is constituted by a screw attached to the screw hole. [4] The motor rotor described in [1] or [2] above, wherein the convex portion is constituted by a metal screw attached to the first ring portion and the second ring portion so as to connect the first ring portion and the second ring portion. [5] A motor rotor according to any one of [1] to [4] above; and a stator arranged to surround the motor rotor. [Explanation of symbols]

[0047] 1, 1A, 1B Rotating Machinery 2, 2A, 2B motor rotor 3 Stator 10 Shaft 11, 11A, 11B First ring part 11a Screw hole 12, 12A, 12B Second ring part 13 Bonded magnets 21 Screw (convex part) 23 First protrusion (protrusion) 25 Bolt (screw, convex part) L Rotation axis

Claims

1. A shaft rotatable about a rotation axis; a first ring portion and a second ring portion each protruding radially outward from an outer circumferential surface of the shaft and provided at a predetermined interval from each other in the direction of the rotation axis; a cylindrical bonded magnet covering an outer circumferential surface of the shaft between the first ring portion and the second ring portion; a protrusion provided on the first ring portion, protruding from a surface of the first ring portion facing the second ring portion and engaging with the bond magnet; A motor rotor comprising:

2. The motor rotor according to claim 1 , wherein the protrusion and the bonded magnet are bonded to each other.

3. The first ring portion is provided with a screw hole extending along the rotation axis direction, The motor rotor according to claim 1 , wherein the protrusion is formed by a screw attached to the screw hole.

4. 2. The motor rotor according to claim 1, wherein the protrusion is formed by a metal screw attached to the first ring portion and the second ring portion so as to connect the first ring portion and the second ring portion.

5. A motor rotor according to any one of claims 1 to 4, and a stator arranged to surround the motor rotor.

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