Motor

Abstract

To prevent removal of a balance weight from a rotor frame.SOLUTION: A motor includes a rotor frame, a rotor, and a stator. The rotor frame has a plurality of ribs. Each rib includes at least one housing hole. The respective ribs are arranged at intervals in a circumferential direction. Each rib extends in a radial direction. The rotor is supported by the rotor frame. The rotor has an annular shape. The stator is disposed at the radial inner side relative to the rotor.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a motor.

Background Art

[0002] In recent years, drones have begun to spread. Generally, a drone has a main body, a plurality of arms extending radially from the main body, and motors attached to the tips of the respective arms. The motors rotate the propellers. This motor has a rotor frame that supports a rotor, and the rotor and the rotor frame rotate (see Patent Document 1).

[0003] Since unbalance depending on component accuracy or assembly accuracy may occur in the rotor and the rotor frame, a weight for balance correction (balance weight) is adhered to the rotor frame.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] When the rotor and the rotor frame rotate, there is a problem that the balance weight comes off the rotor frame due to centrifugal force. Therefore, an object of the present invention is to prevent the balance weight from coming off the rotor frame.

Means for Solving the Problems

[0006] The motor according to the first aspect includes a rotor frame, a rotor, and a stator. The rotor frame has a plurality of ribs. Each of the plurality of ribs includes at least one accommodation hole. Each rib is arranged at intervals in the circumferential direction, and each rib extends in the radial direction. The rotor is supported by the rotor frame. The rotor is annular. The stator is arranged radially inside the rotor.

[0007] According to this configuration, since the accommodation holes are formed in each rib, the balance weight can be firmly attached to the rotor frame by arranging the balance weight in the accommodation hole. As a result, it is possible to prevent the balance weight from coming off the rotor frame.

[0008] The motor according to the second aspect further includes at least one balance weight in the motor according to the first aspect. At least one balance weight is arranged in at least one of the plurality of accommodation holes.

[0009] The motor according to the third aspect is configured as follows in the motor according to the first or second aspect. Each of the plurality of ribs has a plurality of accommodation holes arranged at intervals in the radial direction.

[0010] The motor according to the fourth aspect is configured as follows in the motor according to the third aspect. The plurality of accommodation holes have different opening areas from each other. Specifically, the plurality of accommodation holes of one rib have different opening areas from each other.

[0011] The motor according to the fifth aspect is configured as follows in the motor according to the third or fourth aspect. The plurality of accommodation holes have a smaller opening area as they are located more radially outside. Specifically, the plurality of accommodation holes of one rib have a smaller opening area as they are located more radially outside.

[0012] The motor according to the sixth aspect is configured as follows in the motor according to the third or fourth aspect. Among the plurality of accommodation holes, the opening area is larger for those on the radially outer side. Specifically, among the plurality of accommodation holes formed in one rib, the opening area is larger for those on the radially outer side.

[0013] The motor according to the seventh aspect is configured as follows in the motor according to any one of the third to sixth aspects. The depths of the plurality of accommodation holes are different from each other. Specifically, the depths of the plurality of accommodation holes formed in one rib are different from each other.

[0014] The motor according to the eighth aspect is configured as follows in the motor according to any one of the third to seventh aspects. Among the plurality of accommodation holes, those on the radially outer side are shallower. Specifically, among the plurality of accommodation holes formed in one rib, those on the radially outer side are shallower.

[0015] The motor according to the ninth aspect is configured as follows in the motor according to any one of the third to seventh aspects. Among the plurality of accommodation holes, those on the radially outer side are deeper. Specifically, among the plurality of accommodation holes formed in one rib, those on the radially outer side are deeper.

[0016] The motor according to the tenth aspect is configured as follows in the motor according to the first or second aspect. Each accommodation hole is a long hole extending in the radial direction.

[0017] The motor according to the eleventh aspect is configured as follows in the motor according to the tenth aspect. The width of each accommodation hole becomes narrower as it goes toward the radially outer side.

[0018] The motor according to the twelfth aspect is configured as follows in the motor according to the tenth aspect. The width of each accommodation hole becomes wider as it goes toward the radially outer side.

[0019] The motor according to the thirteenth aspect is configured as follows in the motor according to any one of the tenth to twelfth aspects. Each accommodation hole becomes shallower as it goes toward the radially outer side.

[0020] The motor according to the 14th aspect is configured as follows in the motor according to any one of the 10th to 12th aspects. Each accommodation hole becomes deeper as it goes radially outward.

[0021] The motor according to the 15th aspect is configured as follows in the motor according to any one of the 1st to 14th aspects. The rotor frame has a top plate portion and an inclined portion. The top plate portion is disc-shaped. The inclined portion is arranged radially outside the top plate portion. The inclined portion is annular. Each accommodation hole is arranged radially inside the inclined portion.

Advantages of the Invention

[0022] According to the present invention, it is possible to prevent the balance weight from coming off the rotor frame.

Brief Description of the Drawings

[0023]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Modes for Carrying Out the Invention

[0024] Hereinafter, the motor according to this embodiment will be described with reference to the drawings. In the following description, the axial direction is the direction in which the rotation axis O of the motor extends. The circumferential direction is the circumferential direction of a circle centered on the rotation axis O, and the radial direction is the radial direction of a circle centered on the rotation axis O. The first side in the axial direction means the lower side, and the second side in the axial direction means the upper side.

[0025] As shown in FIG. 1, the motor 100 has a rotor frame 2, a stator frame 3, a rotor 4, a stator 5, and a balance weight 6. The motor 100 is a motor for a drone. Specifically, this motor 100 is used for an industrial drone. The motor 100 is configured to rotate a propeller (not shown) of the drone. The propeller is disposed on the second side in the axial direction with respect to the motor 100. The rotation axis O of the motor 100 extends in the vertical direction. That is, in this embodiment, the axial direction means the vertical direction.

[0026] The drone includes a plurality of such motors 100. Generally, the drone includes four such motors 100. Each motor 100 is attached to the main body portion of the drone via an arm or the like. A battery, a control unit, and the like are housed in the main body portion of the drone.

[0027] [Rotor Frame] FIG. 2 is a perspective view of the rotor frame 2 viewed from the first side in the axial direction. As shown in FIGS. 1 and 2, the rotor frame 2 is configured to support the rotor 4. The rotor frame 2 is configured to rotate together with the rotor 4. The rotor frame 2 also rotates together with the shaft 20. Note that the rotor frame 2 may rotate relative to the shaft 20. The shaft 20 extends in the axial direction. The shaft 20 is rotatably disposed.

[0028] The propeller is fixed to the rotor frame 2 and rotates together with the rotor frame 2. For example, the rotor frame 2 has a plurality of screw holes 25 into which bolts (not shown) are screwed. The propeller is fastened to the rotor frame 2 by bolts.

[0029] The rotor frame 2 has a top plate portion 21, an inclined portion 22, a first cylindrical portion 23, and a plurality of ribs 24. The rotor frame 2 preferably has three or more ribs 24. In the present embodiment, the rotor frame 2 has eight ribs 24.

[0030] The top plate portion 21 is disc-shaped. The top plate portion 21 defines the upper surface of the motor 100. The inclined portion 22 is disposed radially outward of the top plate portion 21. The inclined portion 22 is annular and extends in the circumferential direction. The inclined portion 22 is disposed so as to surround the top plate portion 21. The inclined portion 22 is inclined toward the first side in the axial direction toward the radially outer side. That is, the outer surface of the inclined portion 22 faces the second side in the axial direction and faces the radially outer side.

[0031] The first cylindrical portion 23 extends in the axial direction. Specifically, the first cylindrical portion 23 extends from the outer peripheral edge of the inclined portion 22 toward the first side in the axial direction. The first cylindrical portion 23 defines the outer peripheral surface of the rotor frame 2. The first cylindrical portion 23 extends in the circumferential direction so as to connect the outer peripheral ends of the respective ribs 24.

[0032] Each rib 24 is provided on the surface of the top plate portion 21 facing the first side in the axial direction. That is, each rib 24 is provided on the lower surface of the top plate portion 21. Each rib 24 extends in the radial direction. Specifically, each rib 24 extends from the rotation axis O to the first cylindrical portion 23. That is, each rib 24 extends radially on the top plate portion 21 and on the inclined portion 22.

[0033] The ribs 24 are arranged at intervals in the circumferential direction. That is, the plurality of ribs 24 extend radially about the rotation axis O. Each rib 24 is connected to each other at the radially inner ends.

[0034] Although not particularly limited, the width of each rib 24 can be, for example, about 3.0 to 10.0 mm. The width of each rib 24 means the width on the top plate portion 21 of each rib 24. The thickness of each rib 24 is smaller than the width of each rib 24. Here, the width of the rib 24 means the dimension in the circumferential direction, and the thickness of the rib 24 means the dimension in the axial direction.

[0035] Each rib 24 has a plurality of accommodation holes 241. In this embodiment, each rib 24 has three accommodation holes 241. The plurality of accommodation holes 241 are arranged at intervals in the radial direction in each rib 24. That is, each accommodation hole 241 is arranged along the direction in which each rib 24 extends. Each accommodation hole 241 opens to the first side in the axial direction. Note that each accommodation hole 241 does not penetrate the rotor frame 2 in the axial direction. That is, each accommodation hole 241 does not open to the second side in the axial direction.

[0036] Each accommodation hole 241 is arranged radially inward with respect to the inclined portion 22. That is, each rib 24 extends on the top plate portion 21 and the inclined portion 22, but the accommodation hole 241 is formed in the portion of each rib 24 that extends on the top plate portion 21, and the accommodation hole 241 is not formed in the portion that extends on the inclined portion 22. That is, each accommodation hole 241 is arranged at a position overlapping the top plate portion 21 in the axial view and is not arranged at a position overlapping the inclined portion 22. Each rib 24 has a wider width in the region extending on the inclined portion 22 than on the top plate portion 21.

[0037] Each accommodation hole 241 is arranged at a position overlapping the space between the second cylindrical portion 32 and the third cylindrical portion 33 in the axial view.

[0038] The opening areas and depths of the accommodation holes 241 are the same as each other. Although not particularly limited, for example, the opening area of each accommodation hole 241 is about 0.79 to 50.26 mm 2 or so. Also, the depth of each accommodation hole 241 is about 1.0 to 5.0 mm.

[0039] [Balance weight] The balance weight 6 is disposed in at least one of the plurality of accommodation holes 241. The balance weight 6 is made of metal or resin. For example, the balance weight 6 is cylindrical and is inserted into the accommodation hole 241. Note that the balance weight 6 may be inserted into the accommodation hole 241 and adhered by an adhesive. Also, the balance weight 6 may be formed by pouring a paste-like resin into the accommodation hole 241.

[0040] The balance weight 6 is completely accommodated in the accommodation hole 241. Note that a part of the balance weight 6 may protrude from the accommodation hole 241.

[0041] [Stator frame] As shown in FIG. 1, the stator frame 3 is configured to support the stator 5. The stator frame 3 is disposed non-rotatably. The stator frame 3 rotatably supports the shaft 20 via a plurality of bearing members 7.

[0042] The stator frame 3 has a first connecting portion 31, a second cylindrical portion 32, a third cylindrical portion 33, a fourth cylindrical portion 34, and a second connecting portion 35.

[0043] The second cylindrical portion 32 extends in the axial direction. A plurality of bearing members 7 are attached inside the second cylindrical portion 32. Also, the shaft 20 extends inside the second cylindrical portion 32.

[0044] The third cylindrical portion 33 extends in the axial direction. The third cylindrical portion 33 is disposed radially outside the second cylindrical portion 32. The third cylindrical portion 33 is disposed so as to surround the second cylindrical portion 32. The third cylindrical portion 33 is disposed at a distance from the second cylindrical portion 32 in the radial direction.

[0045] The first connecting portion 31 connects the second cylindrical portion 32 and the third cylindrical portion 33. The shape of the first connecting portion 31 is not particularly limited. For example, the first connecting portion 31 may be an annular plate having a plurality of openings, or may be a plurality of arms extending in the radial direction.

[0046] The fourth cylindrical portion 34 extends in the axial direction. The fourth cylindrical portion 34 is disposed radially outside the third cylindrical portion 33. The fourth cylindrical portion 34 is disposed so as to surround the third cylindrical portion 33. The fourth cylindrical portion 34 is disposed at a distance from the third cylindrical portion 33 in the radial direction. The fourth cylindrical portion 34 is shorter in the axial direction than the third cylindrical portion 33.

[0047] The second connecting portion 35 connects the third cylindrical portion 33 and the fourth cylindrical portion 34. The shape of the second connecting portion 35 is not particularly limited. For example, the second connecting portion 35 may be an annular plate having a plurality of openings, or may be a plurality of arms extending in the radial direction.

[0048] [Rotor] The rotor 4 is supported by the rotor frame 2. Specifically, the rotor 4 is supported by the first cylindrical portion 23 of the rotor frame 2. The rotor 4 rotates integrally with the rotor frame 2. The rotor 4 is annular. The rotor 4 has a yoke 41 and a plurality of permanent magnets 42.

[0049] The yoke 41 is cylindrical. The yoke 41 is fixed to the rotor frame 2. Specifically, the yoke 41 is attached to the first cylindrical portion 23 of the rotor frame 2. Note that the outer peripheral surface of the yoke 41 is fixed to the inner peripheral surface of the first cylindrical portion 23.

[0050] The end portion 41a of the yoke 41 on the second side in the axial direction is attached to the first cylindrical portion 23. The yoke 41 protrudes from the first cylindrical portion 23 toward the first side in the axial direction. That is, the portion of the yoke 41 excluding the end portion 41a is exposed toward the radially outer side. The yoke 41 cooperates with the rotor frame 2 and the stator frame 3 to constitute the outer shell of the motor 100.

[0051] Each permanent magnet 42 is attached to the inner peripheral surface of the yoke 41. The permanent magnets 42 are arranged at intervals in the circumferential direction. Each permanent magnet 42 is arranged radially outside the stator 5. That is, the permanent magnets 42 are arranged so as to surround the stator 5. Note that the permanent magnets 42 are arranged at a distance from the stator 5 in the radial direction.

[0052] [Stator] The stator 5 is annular. The stator 5 is arranged radially inside the rotor 4. The stator 5 is arranged so as not to rotate. The stator 5 is supported by the stator frame 3. The stator 5 is arranged radially outside the third cylindrical portion 33 of the stator frame 3. That is, the stator 5 is arranged so as to surround the third cylindrical portion 33. The stator 5 is supported by the third cylindrical portion 33.

[0053] The stator 5 has a stator core 51 and a plurality of coil portions 52. The stator core 51 is formed by laminating a plurality of electromagnetic steel sheets.

[0054] The coil portion 52 is wound around the stator core 51. Specifically, the coil portion 52 is wound around the teeth of the stator core 51. Note that an insulating layer 53 is interposed between the coil portion 52 and the stator core 51.

[0055] [Modification Example] As described above, the embodiments of the present invention have been described. However, the present invention is not limited to these, and various modifications are possible without departing from the spirit of the present invention. Note that the following modification examples can basically be applied simultaneously.

[0056] (a) In the above embodiment, the opening areas and depths of the respective accommodation holes 241 are the same as each other. However, the configuration of the rotor frame 2 is not limited to this. That is, the opening areas of the respective accommodation holes 241 may be different from each other.

[0057] For example, as shown in FIG. 3, in each rib 24, the opening areas of the plurality of accommodation holes 241 may be smaller for those closer to the radially outer side. Alternatively, as shown in FIG. 4, in each rib 24, the opening areas of the plurality of accommodation holes 241 may be larger for those closer to the radially outer side.

[0058] Also, the depths of the respective accommodation holes 241 may be different from each other. For example, as shown in FIG. 5, in each rib 24, the depths of the plurality of accommodation holes 241 may be shallower for those closer to the radially outer side. Alternatively, as shown in FIG. 6, in each rib 24, the depths of the plurality of accommodation holes 241 may be deeper for those closer to the radially outer side.

[0059] (b) In the above-described embodiment, the accommodation hole 241 was circular in the axial view, but the shape of the accommodation hole 241 is not limited thereto. For example, as shown in FIG. 7, each accommodation hole 241 may be a long hole extending in the radial direction. The width of each accommodation hole 241 is constant along the radial direction. Here, the width of the accommodation hole 241 means the dimension in the circumferential direction.

[0060] Note that, as shown in FIG. 8, the width of each accommodation hole 241 may become narrower as it goes toward the radially outer side. Alternatively, as shown in FIG. 9, the width of each accommodation hole 241 may widen as it goes toward the radially outer side.

[0061] Also, the depths of the respective accommodation holes 241 may be constant or different along the radial direction. For example, as shown in FIG. 10, the depth of each accommodation hole 241 may become shallower as it goes toward the radially outer side. Alternatively, as shown in FIG. 11, the depth of each accommodation hole 241 may become deeper as it goes toward the radially outer side.

[0062] (c) In the above-described embodiment, the rotor frame has the first cylindrical portion and the rotor is supported by the first cylindrical portion, but the configuration is not limited thereto. For example, the rotor may be supported by each rib.

[0063] (d) In the above embodiment, the motor 100 had the balance weight 6, but the motor 100 may not have the balance weight 6. For example, a motor 100 that does not require balance correction does not have the balance weight 6.

Explanation of Signs

[0064] 2: Rotor Frame 22: Inclined Portion 24: Rib 241: Accommodation Hole 4: Rotor 5: Stator 6: Balance Weight 100: Motor

Claims

1. A rotor frame having a plurality of ribs each including at least one receiving hole and arranged at intervals in the circumferential direction and extending in the radial direction, An annular rotor supported by the rotor frame, A stator arranged radially inside the rotor, A motor comprising the above.

2. At least one balance weight arranged in at least one of the plurality of receiving holes, The motor according to claim 1, further comprising the above.

3. Each of the plurality of ribs has a plurality of the receiving holes arranged at intervals in the radial direction, The motor according to claim 1.

4. The plurality of receiving holes have different opening areas from each other, The motor according to claim 3.

5. The plurality of receiving holes have a smaller opening area as they are located more radially outside, The motor according to claim 3.

6. The plurality of receiving holes have a larger opening area as they are located more radially outside, The motor according to claim 3.

7. The plurality of receiving holes have different depths from each other, The motor according to claim 3.

8. The plurality of receiving holes are shallower as they are located more radially outside, The motor according to claim 3.

9. The plurality of receiving holes are deeper as they are located more radially outside, The motor according to claim 3.

10. Each of the receiving holes is a long hole extending in the radial direction, The motor according to claim 1.

11. Each of the receiving holes becomes narrower as it goes radially outward, The motor according to claim 10.

12. Each of the receiving holes becomes wider as it goes radially outward, The motor according to claim 10.

13. Each of the receiving holes becomes shallower as it goes radially outward, The motor according to claim 10.

14. Each of the receiving holes becomes deeper as it goes radially outward, The motor according to claim 10.

15. The rotor frame has a disk-shaped top plate portion and an annular inclined portion arranged radially outside the top plate portion, Each of the receiving holes is arranged radially inside the inclined portion, The motor according to claim 1.

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