motor

Abstract

To improve the exhaust efficiency of air inside the motor. [Solution] The motor comprises a stator and a rotor. The rotor is rotatably arranged. The rotor has a rotor frame and permanent magnets. The permanent magnets are supported by the rotor frame. The rotor frame has a cylindrical portion, an inclined portion, and a plurality of openings. The cylindrical portion is positioned radially outward relative to the stator. The cylindrical portion supports the permanent magnets. The inclined portion is positioned on the first axial side relative to the stator. The stator extends radially inward and axially to the first side from the first axial end of the cylindrical portion. Each opening is formed in the inclined portion. Each opening is spaced apart from one another in the circumferential direction.

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. These motors have a rotor and a stator, and the rotor rotates.

[0003] The drone motor disclosed in Patent Document 1 has a punching plate attached to the top plate of the housing. Thus, it is configured to exhaust the air inside the motor axially from below to above.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the motor configured as described above, it is desired to efficiently exhaust the air inside the motor. Therefore, an object of the present invention is to improve the exhaust efficiency of the air inside the motor.

Means for Solving the Problems

[0006] A motor according to the first embodiment comprises a stator and a rotor. The rotor is rotatably arranged. The rotor has a rotor frame and permanent magnets. The permanent magnets are supported by the rotor frame. The rotor frame has a cylindrical portion, an inclined portion, and a plurality of openings. The cylindrical portion is arranged radially outward from the stator. The cylindrical portion supports the permanent magnets. The inclined portion is arranged on the first axial side relative to the stator. The stator extends radially inward and axially to the first side from the first axial end of the cylindrical portion. Each opening is formed in the inclined portion. Each opening is spaced apart from one another in the circumferential direction.

[0007] The inventors have found that, because the air inside the motor flows radially outward due to centrifugal force, in the case of conventional motors that have an opening in the top plate, the exhaust direction is perpendicular to the radially outward airflow direction, resulting in poor exhaust efficiency. Therefore, the motor according to the first embodiment has an inclined portion on the rotor frame and an opening formed in the inclined portion. With this configuration, the exhaust direction can be brought closer to the radially outward airflow direction, thereby improving exhaust efficiency.

[0008] The motor according to the second embodiment is configured as follows in the motor according to the first embodiment. Each opening is composed of a plurality of slits.

[0009] The motor according to the third embodiment is configured as follows in the motor according to the second embodiment. Each slit extends in the radial direction.

[0010] The motor according to the fourth embodiment is configured as follows in the motor according to the third embodiment. Each slit extends from the inclined portion to the cylindrical portion.

[0011] The motor according to the fifth embodiment is configured as follows in the motor according to any of the second to fourth embodiments: The inclined portion has a partition portion. The partition portion is defined by a pair of adjacent slits. The partition portion has a corner portion facing the second side in the axial direction. This corner portion has a chamfered shape.

[0012] The motor according to the sixth embodiment is configured as follows in the motor according to any of the second to fourth embodiments: The inclined portion has a partition portion. The partition portion is defined by a pair of adjacent slits. The partition portion has a corner portion facing the first side in the axial direction. This corner portion has a chamfered shape.

[0013] The motor according to the seventh embodiment is configured as follows in the motor according to any of the second to fourth embodiments: The inclined portion has a partition portion. The partition portion is defined by a pair of adjacent slits. The partition portion has a first corner portion and a second corner portion. The first corner portion faces the first side in the axial direction and has a chamfered shape. The second corner portion faces the second side in the axial direction and has a chamfered shape.

[0014] The motor according to the eighth embodiment is configured as follows in the motor according to any of the first to seventh embodiments: The rotor frame has a plurality of ribs. Each rib extends radially. Each rib and each opening are arranged alternately in the circumferential direction. [Effects of the Invention]

[0015] According to the present invention, the exhaust efficiency of air inside the motor can be improved. [Brief explanation of the drawing]

[0016] [Figure 1] Cross-sectional view of the motor. [Figure 2] Perspective view of the motor. [Figure 3] Cross-sectional perspective view of the rotor frame. [Figure 4] Cross-sectional view of the partition section related to the modified version. [Modes for carrying out the invention]

[0017] 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. In this embodiment, the first side in the axial direction means the upper side in FIG. 1, and the second side in the axial direction means the lower side in FIG. 1.

[0018] As shown in FIGS. 1 and 2, the motor 100 has a stator 2 and a rotor 3. 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 first 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.

[0019] 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.

[0020] <Stator> The stator 2 is disposed non-rotatably. The stator 2 is disposed on the second side in the axial direction with respect to the rotor 3. The stator 2 has a stator frame 21, a stator core 22, and a plurality of coil portions 23.

[0021] The stator frame 21 has a first cylindrical portion 211, a second cylindrical portion 212, a third cylindrical portion 213, a first connecting portion 214, and a second connecting portion 215.

[0022] The first cylindrical portion 211 extends in the axial direction. A plurality of bearing members 7 are attached within the first cylindrical portion 211. Also, a shaft portion 30 extends within the first cylindrical portion 211. The first cylindrical portion 211 rotatably supports the shaft portion 30 via the bearing members 7.

[0023] The second cylindrical portion 212 extends in the axial direction. The second cylindrical portion 212 is disposed radially outside the first cylindrical portion 211. The second cylindrical portion 212 is arranged so as to surround the first cylindrical portion 211. The second cylindrical portion 212 is arranged at a distance from the first cylindrical portion 211 in the radial direction.

[0024] The third cylindrical portion 213 extends in the axial direction. The third cylindrical portion 213 is disposed radially outside the second cylindrical portion 212. The third cylindrical portion 213 is arranged so as to surround the second cylindrical portion 212. The third cylindrical portion 213 is arranged at a distance from the second cylindrical portion 212 in the radial direction. The third cylindrical portion 213 is shorter in the axial direction than the second cylindrical portion 212.

[0025] The first connecting portion 214 connects the first cylindrical portion 211 and the second cylindrical portion 212. The shape of the first connecting portion 214 is not particularly limited. For example, the first connecting portion 214 may be an annular plate having a plurality of openings, or may be a plurality of arms extending in the radial direction.

[0026] The second connecting portion 215 connects the second cylindrical portion 212 and the third cylindrical portion 213. The shape of the second connecting portion 215 is not particularly limited. For example, the second connecting portion 215 may be an annular plate having a plurality of openings, or may be a plurality of arms extending in the radial direction.

[0027] The bottom surface of the stator frame 21 is constituted by the first connecting portion 214 and the second connecting portion 215. The bottom surface of the stator frame 21 has a plurality of openings (not shown). Through each of these openings, air flows into the motor 100.

[0028] The stator core 22 is supported by the stator frame 21. The stator core 22 is positioned radially outward relative to the second cylindrical portion 212 of the stator frame 21. That is, the stator core 22 is positioned to surround the second cylindrical portion 212. The stator core 22 is supported by the second cylindrical portion 212. The stator core 22 is constructed by laminating multiple electromagnetic steel sheets.

[0029] The coil section 23 is wound around the stator core 22. More specifically, the coil section 23 is wound around the teeth of the stator core 22. An insulating layer (not shown) is interposed between the coil section 23 and the stator core 22.

[0030] <Rotor> The rotor 3 is rotatably positioned. The rotor 3 is positioned on the first axial side relative to the stator 2. A propeller is attached to the rotor 3. The rotor 3 rotates integrally with the propeller. The rotor 3 has a rotor frame 31, a yoke 32, and a plurality of permanent magnets 33.

[0031] The rotor frame 31 is configured to support the yoke 32 and the permanent magnet 33. The rotor frame 31 is configured to rotate together with the yoke 32 and the permanent magnet 33. The rotor frame 31 is rotatably supported by the stator 2. In detail, the rotor frame 31 is supported by the stator 2 via a shaft portion 30 and a bearing member 7.

[0032] The rotor frame 31 rotates together with the shaft portion 30. The rotor frame 31 is integrally formed with the shaft portion 30 from a single component, but it may be composed of separate components from the shaft portion 30. If the rotor frame 31 and the shaft portion 30 are separate components, the rotor frame 31 may rotate relative to the shaft portion 30. The shaft portion 30 extends in the axial direction. The shaft portion 30 is rotatably arranged.

[0033] The propeller is fixed to the rotor frame 31 and rotates with the rotor frame 31. For example, the rotor frame 31 has a plurality of screw holes 310 into which bolts (not shown) are screwed. The propeller is fastened to the rotor frame 31 by bolts. As the propeller rotates, air inside the motor is exhausted from the second side in the axial direction toward the first side.

[0034] Figure 3 is a cross-sectional perspective view of the rotor frame 31. As shown in Figures 1 to 3, the rotor frame 31 has a cylindrical portion 311, an inclined portion 312, a top plate portion 313, a plurality of openings 314, and a plurality of ribs 315. Preferably, the rotor frame 31 has three or more ribs 315. In this embodiment, however, the rotor frame 31 has eight ribs 315.

[0035] The cylindrical portion 311 extends in the axial direction. The cylindrical portion 311 is positioned radially outward relative to the stator 2. More specifically, the cylindrical portion 311 is positioned radially outward relative to the stator core 22. The cylindrical portion 311 surrounds the stator core 22.

[0036] The cylindrical portion 311 is configured to support the permanent magnet 33. More specifically, the cylindrical portion 311 supports the permanent magnet 33 which is attached to the yoke 32. The cylindrical portion 311 and the third cylindrical portion 213 define the outer circumferential surface of the motor 100.

[0037] The inclined portion 312 extends radially inward and upward from the first axial end (upper end) of the cylindrical portion 311. The inclined portion 312 is an annular shape extending in the circumferential direction. The inclined portion 312 is inclined such that its inner circumferential end is positioned on the first axial side relative to its outer circumferential end. The surface of the inclined portion 312 facing the first axial side faces the first axial side and also faces radially outward. The surface of the inclined portion 312 facing the second axial side faces the second axial side and also faces radially inward. The inclined portion 312 is arranged to surround the top plate portion 313.

[0038] The top plate portion 313 is disc-shaped. The top plate portion 313 defines the upper surface of the motor 100. The top plate portion 313 extends perpendicular to the axial direction. The inclined portion 312 is positioned between the cylindrical portion 311 and the top plate portion 313. The inclined portion 312 is connected to the upper end of the cylindrical portion 311 and the outer peripheral end of the top plate portion 313.

[0039] Each opening 314 is formed in the inclined portion 312. Each opening 314 is spaced apart from one another in the circumferential direction. Each opening 314 is composed of multiple slits 316.

[0040] Each slit 316 extends radially. Each slit 316 is spaced apart from each other in the circumferential direction. Each slit 316 extends from the inclined portion 312 to the cylindrical portion 311. That is, each slit 316 is formed from the inclined portion 312 to the cylindrical portion 311. Note that each slit 316 is not formed in the top plate portion 313.

[0041] Each slit 316 extends radially and also axially. That is, each slit 316 has a bent portion between the radially extending portion and the axially extending portion. In addition, the portion of each slit 316 formed in the inclined portion 312 is longer than the portion formed in the cylindrical portion 311.

[0042] Each slit 316 is positioned to overlap with each coil portion 23 in an axial view. However, each slit 316 does not overlap with the yoke 32 and the permanent magnet 33 in a radial view. Each slit 316 is positioned on the first axial side relative to the yoke 32 and the permanent magnet 33.

[0043] Each rib 315 is provided on the surface of the top plate portion 313 and the inclined portion 312 facing the second axial side. That is, each rib 315 is provided on the lower surface of the top plate portion 313 and the inclined portion 312. Each rib 315 extends radially. More specifically, each rib 315 extends from the axis of rotation O to the cylindrical portion 311. That is, each rib 315 extends radially on the top plate portion 313 and the inclined portion 312.

[0044] Each rib 315 is spaced apart from the others in the circumferential direction. That is, the multiple ribs 315 extend radially around the axis of rotation O. Each rib 315 extends radially between a pair of adjacent openings 314. Each rib 315 and each opening 314 are arranged alternately in the circumferential direction. Each rib 315 is connected to the others at its radially inner end.

[0045] The width of each rib 315 is greater in the portion formed on the inclined portion 312 than in the portion formed on the top plate portion 313. The thickness of each rib 315 is less than the width of each rib 315. Here, the width of the rib 315 refers to the circumferential dimension, and the thickness of the rib 315 refers to the axial dimension.

[0046] Furthermore, it is preferable to reduce the radius of curvature of the pair of corners of each rib 315 that face the second axial side. For example, it is preferable that each corner of each rib 315 does not have a chamfered shape. The radius of curvature R of each corner of each rib 315 can be approximately R0.2 mm to R0.4 mm.

[0047] The yoke 32 is cylindrical. The yoke 32 is fixed to the cylindrical portion 311 of the rotor frame 31. The outer surface of the yoke 32 is fixed to the inner surface of the cylindrical portion 311.

[0048] Each permanent magnet 33 is supported by the rotor frame 31. More specifically, each permanent magnet 33 is mounted on the inner circumferential surface of a yoke 32 attached to a cylindrical portion 311. Each permanent magnet 33 is spaced apart in the circumferential direction. Each permanent magnet 33 is positioned radially outward from the stator 2. That is, the permanent magnets 33 are arranged to surround the stator 2. Note that the permanent magnets 33 are spaced apart from the stator 2 in the radial direction.

[0049] [Differentiation] Although embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications are possible without departing from the spirit of the invention. Furthermore, the following modifications can basically be applied simultaneously.

[0050] (a) In the above embodiment, the rotor frame 31 had a cylindrical portion 311, an inclined portion 312, and a top plate portion 313, but it does not have to have a top plate portion 313. That is, the inclined portion 312 may extend from the cylindrical portion 311 to the vicinity of the rotation axis O.

[0051] (b) Each slit 316 may extend in the circumferential direction rather than the radial direction. In this case, each slit 316 is spaced apart from one another in the radial direction.

[0052] (c) In the above embodiment, each slit 316 was formed in the inclined portion 312 and the cylindrical portion 311, but each slit 316 may be formed only in the inclined portion 312. In other words, each slit 316 does not have to be formed in the cylindrical portion 311.

[0053] Furthermore, in the above embodiment, each slit 316 was not formed in the top plate portion 313, but it may be formed in the top plate portion 313. Also, each slit 316 may be formed only in the inclined portion 312 and the top plate portion 313, and not in the cylindrical portion 311.

[0054] (d) As shown in Figure 4, the inclined portion 312 has a plurality of partition portions 317. The partition portions 317 are defined by a pair of adjacent slits 316. Of the four corners of the partition portion 317, the pair of first corners 318 facing the first side in the axial direction and the pair of second corners 319 facing the second side in the axial direction have a chamfered shape. Specifically, the pair of first corners 318 and the pair of second corners 319 have an R-chamfered shape. The first corners 318 and the second corners 319 may be chamfered during the casting stage of the rotor frame 31, or the chamfering may be done after the rotor frame 31 has been cast.

[0055] The radius of curvature at the first corner 318 and the second corner 319 is preferably larger than the radius of curvature at the corner of each rib 315. For example, the radius of curvature at the first corner 318 and the second corner 319 can be R0.4 mm or larger.

[0056] Furthermore, of the four corners 318 of the partition portion 317, only the pair of first corners 318 may have a chamfered shape, or only the pair of second corners 319 may have a chamfered shape. Also, the chamfered shape may be a C-shaped chamfer instead of an R-shaped chamfer. [Explanation of symbols]

[0057] 2: Status 3: Rotor 31: Rotor frame 311: Cylindrical section 312: Inclined part 314: Opening 315: Rib 316: Slit 317: Partition section 33: Permanent magnet 100: Motor

Claims

1. stator and, A rotor that is rotatably positioned, Equipped with, The rotor comprises a rotor frame and permanent magnets supported by the rotor frame. The rotor frame is A cylindrical portion is positioned radially outward from the stator and supports the permanent magnet, An inclined portion is positioned on the first axial side of the stator and extends radially inward and toward the first axial side from the first axial end of the cylindrical portion, Multiple openings are formed in the inclined portion and are spaced apart from each other in the circumferential direction, Having, Motor.

2. Each of the aforementioned openings is composed of a plurality of slits. The motor according to claim 1.

3. Each of the aforementioned slits extends in the radial direction, The motor according to claim 2.

4. Each of the aforementioned slits extends from the inclined portion to the cylindrical portion, The motor according to claim 3.

5. The inclined portion has a partition defined by a pair of adjacent slits, The partition portion has a corner portion with a chamfered shape facing the second side in the axial direction. The motor according to claim 2.

6. The inclined portion has a partition defined by a pair of adjacent slits, The partition portion has a corner portion with a chamfered shape facing the first side in the axial direction. The motor according to claim 2.

7. The inclined portion has a partition defined by a pair of adjacent slits, The partition portion has a first corner portion facing the first axial side and having a chamfered shape, and a second corner portion facing the second axial side and having a chamfered shape. The motor according to claim 2.

8. The rotor frame has a plurality of ribs extending in the radial direction, Each of the aforementioned ribs and each of the aforementioned openings are arranged alternately in the circumferential direction. The motor according to claim 1.

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