MOTOR

Abstract

The aim is to prevent a balance weight from becoming detached from a rotor frame. The present motor comprises a rotor frame, a rotor, and a stator. The rotor frame has a plurality of webs. The plurality of webs each contain one or more receiving openings. The plurality of webs are arranged at intervals from one another in a circumferential direction. The plurality of webs each extend in a radial direction. The rotor is supported by the rotor frame. The rotor has a ring shape. The stator is arranged radially inside the rotor.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims priority from Japanese application 2023-223488 filed on December 28, 2023, the contents of which are hereby incorporated by reference. TECHNICAL FIELD

[0002] The invention relates to an engine. BACKGROUND

[0003] In recent years, drones have become increasingly popular. A typical drone has a drone body, several arms extending radially from the body, and several motors, each attached to the distal ends of the drones. The motors rotate propellers. Each motor has a rotor frame that supports a rotor; the rotor and rotor frame are rotated (see description of US Patent Application Publication No. 2019 / 0181701).

[0004] Depending on the dimensional accuracy or the assembly accuracy, the rotor and the rotor frame could create an imbalance, which is why a weight is attached to the rotor frame for balance adjustment. BRIEF DESCRIPTION OF THE INVENTION

[0005] However, an undesirable disadvantage is that the counterweight detaches from the rotor frame due to centrifugal forces generated by the rotation of the rotor and rotor frame. Therefore, the object of the invention is to prevent the counterweight from detaching from the rotor frame.

[0006] A motor according to a first aspect of the invention comprises a rotor frame, a rotor, and a stator. The rotor frame has a plurality of webs. The plurality of webs each has a receiving opening. The plurality of webs are arranged at intervals from one another in a circumferential direction. The plurality of webs each extend in a 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, the plurality of webs are each provided with a receiving opening. Therefore, the counterweight can be firmly attached to the rotor frame by placing it in the receiving opening. This prevents the counterweight from detaching from the rotor frame.

[0008] A motor according to a second aspect of the invention relates to a motor according to the first aspect and further comprises at least one counterweight. The at least one counterweight is arranged in at least one of the receiving openings.

[0009] A motor according to a third aspect of the invention relates to the motor according to the first and second aspects and is configured as follows. The plurality of webs each have a plurality of receiving openings arranged at intervals from each other in the radial direction.

[0010] A motor according to a fourth aspect of the invention relates to the motor according to the third aspect and is configured as follows. The plurality of receiving holes differ from each other in their opening areas. In detail, the plurality of receiving holes included in each web differ in their opening areas.

[0011] A motor according to a fifth aspect of the invention relates to the motor according to the third or fourth aspect and is configured as follows. The plurality of receiving holes are oriented radially outwardly in descending order with respect to their opening area. In detail, the plurality of receiving holes included in each web are oriented radially outwardly in descending order with respect to their opening area.

[0012] A motor according to a sixth aspect of the invention relates to the motor according to the third or fourth aspect and is configured as follows. The plurality of receiving openings are oriented so as to ascend radially outward with respect to their opening area. In detail, the plurality of receiving openings contained in each web are oriented so as to ascend radially outward with respect to their opening area.

[0013] A motor according to a seventh aspect of the invention relates to the motor according to any one of the third to sixth aspects and is configured as follows. The plurality of receiving holes differ from each other in terms of their depth. In detail, the plurality of receiving holes contained in each web differ in terms of their depth.

[0014] A motor according to an eighth aspect of the invention relates to the motor according to any one of the third to seventh aspects and is configured as follows. The plurality of receiving openings are oriented in a radially outwardly descending manner in depth. In detail, the plurality of receiving openings included in each web are oriented in a radially outwardly descending manner in depth.

[0015] A motor according to a ninth aspect of the invention relates to the motor according to any one of aspects three to seven and is configured as follows. The plurality of receiving openings are oriented so as to increase radially outward in depth. In detail, the plurality of openings contained in each web are oriented so as to increase radially outward in depth.

[0016] A motor according to a tenth aspect of the invention relates to the motor according to the first or second aspect and is configured as follows. Each of the receiving holes has the shape of an elongated hole extending in the radial direction.

[0017] A motor according to an eleventh aspect of the invention relates to the motor according to the tenth aspect and is configured as follows. The width of each receiving opening gradually decreases radially outward.

[0018] A motor according to a twelfth aspect of the invention relates to the motor according to the tenth aspect and is configured as follows. The width of the receiving openings gradually increases radially outward.

[0019] A motor according to a thirteenth aspect of the invention relates to the motor according to any one of the tenth to twelveth aspects and is configured as follows. The depth of the receiving openings gradually decreases radially outward.

[0020] A motor according to a fourteenth aspect of the invention relates to the motor according to any one of the tenth to twelveth aspects and is configured as follows. The depth of the receiving holes gradually increases radially outward.

[0021] A motor according to a fifteenth aspect of the invention relates to the motor according to any one of the first to fourteenth aspects and is configured as follows. The rotor frame has an upper plate portion and a slant portion. The upper plate portion is disc-shaped. The slant portion is arranged radially outside the upper plate portion. The slant portion is annular. The receiving openings are arranged radially inside the slant portion.

[0022] Overall, the present invention can prevent a counterweight from becoming detached from a rotor frame. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a sectional view of an engine; Fig. 2 is a perspective view of a rotor frame; Fig. 3 is a perspective view of a rotor frame according to an example in a modification; Fig. 4 is an enlarged perspective view of a rotor frame according to another example in the modification; Fig. 5 is a sectional view of a rotor frame according to still another example in the modification; Fig. 6 is a sectional view of a rotor frame according to still another example in the modification; Fig. 7 is a perspective view of a rotor frame according to an example in another modification; Fig. 8 is an enlarged perspective view of a rotor frame according to another example in the further modification; Fig. 9 is an enlarged perspective view of a rotor frame according to still another example in the further modification; Fig. 10 is a sectional view of a rotor frame according to still another example in the further modification; Fig. 11 is a sectional view of a rotor frame according to still another example in the further modification. DETAILED DESCRIPTION

[0023] A motor according to the present embodiment will be explained below with reference to the accompanying drawings. It should be noted that the term "axial direction" in the following description refers to an extending direction of the rotation axis O of the motor. On the other hand, the term "circumferential direction" refers to a circumferential direction of an imaginary circle around the rotation axis O, and the term "radial direction" refers to a radial direction of the imaginary circle around the rotation axis O. Further, the term "first side in the axial direction" means a lower side, and the term "second side in the axial direction" means an upper side.

[0024] As in Fig. 1, the motor 100 includes a rotor frame 2, a stator frame 3, a rotor 4, a stator 5, and at least one balance weight 6. The motor 100 is a drone motor. In detail, the motor 100 is used for an industrial drone. The motor 100 is configured to rotate a propeller of the drone (not shown in the drawings). The propeller is arranged on the second side of the motor 100 in the axial direction. The rotation axis O of the motor 100 extends in an up-and-down direction. In other words, the axial direction in the present preferred embodiment refers to the up-and-down direction.

[0025] The drone contains a plurality of motors of the same type as the motor 100. Typically, a drone has four motors 100. Each motor 100 is attached to a body portion of the drone by arms or the like. A battery, a control unit, etc., are housed in the body portion of the drone. [Rotor frame]

[0026] Fig. 2 shows the rotor frame 2 in a perspective view from the first side in the axial direction. As in Fig. 1 and Fig. As shown in Figure 2, the rotor frame 2 is configured to support the rotor 4. The rotor frame 2 is configured to rotate as a unit with the rotor 4. Furthermore, the rotor frame 2 is rotated as a unit with a shaft 20. It should be noted that the rotor frame 2 can rotate relative to the shaft 20. The shaft 20 extends in the axial direction. The shaft 20 is rotatably arranged.

[0027] The propeller is attached to the rotor frame 2 and rotates as a unit with the rotor frame 2. For example, the rotor frame 2 has a plurality of threaded openings 25 into which a plurality of bolts (not shown in the drawing) are screwed. The propeller is attached to the rotor frame 2 with these bolts.

[0028] The rotor frame 2 has an upper plate portion 21, a slant portion 22, a first cylindrical portion, and a plurality of webs 24. Preferably, the rotor frame 2 has three or more webs 24. Note that in the present embodiment, the rotor frame 2 has eight webs 24.

[0029] The upper plate portion 21 is disc-shaped. The upper plate portion 21 defines the top surface of the motor 100. The bevel portion 22 is arranged radially outside the upper plate portion 21. The bevel portion 22 has the shape of a ring extending in the circumferential direction. The bevel portion 22 is arranged to enclose the upper plate portion 21. The bevel of the bevel portion 22 extends radially outward toward the first side in the axial direction. In other words, the outer side surface of the bevel portion 22 faces the second side in the axial direction and faces radially outward.

[0030] 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 to 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 to connect the outer peripheral ends of the webs 24.

[0031] The ribs 24 are arranged in the upper plate portion 21 on a surface facing the second side in the axial direction. In other words, the ribs 24 are provided on the underside of the upper plate portion 21. The ribs 24 each extend in the radial direction. In detail, each rib 24 extends from the rotation axis O to the first cylindrical portion 23. In other words, each rib 24 extends in the radial direction not only on the upper plate portion 21 but also on the inclined portion 22.

[0032] The webs 24 are arranged at intervals from one another in the circumferential direction. In other words, the webs 24 extend radially around the rotation axis O. It should be noted that the webs 24 are connected to one another at their radially inner ends.

[0033] The width of each land 24 can be approximately 3.0 to 10.0 mm, although this is not limited. Note that the "width" of each land 24 refers to the width of each land 24 on the upper plate portion 21. The thickness of each land 24 is smaller than its width. Here, the "width" of each land 24 refers to its dimension in the circumferential direction, while the term "thickness" refers to its dimension in the axial direction.

[0034] Each web 24 has a plurality of receiving openings 241. It should be noted that in the present preferred embodiment, each web 24 has three receiving openings 241. The plurality of receiving openings 241 are arranged at intervals from one another in the radial direction. In other words, the receiving openings 241 are aligned along the extension direction of each web 24. Each receiving opening 241 is open to the first side in the axial direction. It should be noted that the respective receiving opening 241 does not penetrate the rotor frame 2 in the axial direction. In other words, the respective receiving opening 241 is not open to the second side in the axial direction.

[0035] The receiving holes 241 are arranged radially inside the inclined portion 22. In other words, although each ridge 24 extends not only on the upper plate portion 21 but also on the inclined portion 22, the receiving holes 241 are provided in a portion extending on the upper plate portion 21 in each ridge 24, without being provided in a portion provided on the inclined portion 22 of each rib 24. In other words, as viewed in the axial direction, the receiving holes 241 are arranged to overlap with the upper plate portion 21 but not with the inclined portion 22. Each ridge 24 is wider in its portion extending on the inclined portion 22 than in its portion extending on the upper plate portion 21.

[0036] Viewed in the axial direction, the receiving openings 241 are arranged to overlap with a space between a second cylindrical portion 32 and a third cylindrical portion 33.

[0037] The opening area and the depth of the respective receiving openings 241 are identical. The opening area of each receiving opening 241 is, for example, approximately 0.79 to 50.26 mm 2 , although there is no specific limitation to this value. The depth of each receiving opening 241, however, is approximately 1.0 to 5.0 mm. [Balance weight]

[0038] The at least one balance weight 6 is arranged in at least one of the plurality of receiving openings 241. Each balance weight 6 is made of metal or resin. For example, each balance weight 6 is columnar and is inserted into a respective receiving opening 241. Note that each balance weight 6 can be inserted into the respective receiving opening 241 and secured with adhesive. Alternatively, the balance weight 6 can be made of a resin paste that is poured into the corresponding receiving opening 241.

[0039] Each counterweight 6 is completely received in the corresponding receiving opening 241. It should be noted that each counterweight 6 may partially protrude from the corresponding receiving opening 241. [Stator frame]

[0040] How Fig. 1, the stator frame 3 is configured to support the stator 5. The stator frame 3 is arranged non-rotatably. The stator frame 3 supports the shaft 20 via a plurality of bearing elements 7 such that the shaft 20 can rotate.

[0041] The stator frame 3 has a first connecting portion 31, the second cylindrical portion 32, the third cylindrical portion 33, a fourth cylindrical portion 34 and a second connecting portion 35.

[0042] The second cylindrical portion 32 extends in the axial direction. The plurality of bearing elements 7 are fixed to the interior of the second cylindrical portion 32. Furthermore, the shaft 20 extends inside the second cylindrical portion 32.

[0043] The third cylindrical portion 33 extends in the axial direction. The third cylindrical portion 33 is arranged radially outside the second cylindrical portion 32. The third cylindrical portion 33 is arranged to enclose the second cylindrical portion 32. The third cylindrical portion 33 is arranged radially at a distance from the second cylindrical portion 32.

[0044] The first connecting portion 31 connects the second and third cylindrical portions 32 and 33 to each other. The shape of the first connecting portion 31 is not particularly limited. For example, the first connecting portion 31 may be formed in the shape of an annular plate having a plurality of openings, or alternatively, in the shape of a plurality of radially extending arms.

[0045] The fourth cylindrical portion 34 extends in the axial direction. The fourth cylindrical portion 34 is arranged radially outside the third cylindrical portion 33. The fourth cylindrical portion 34 is arranged to enclose the third cylindrical portion 33. The fourth cylindrical portion 34 is arranged radially at a distance from the third cylindrical portion 33. The fourth cylindrical portion 34 has a smaller axial length than the third cylindrical portion 33.

[0046] The second connecting portion 35 connects the third and fourth cylindrical portions 33 and 34 to each other. The shape of the second connecting portion 31 is not particularly limited. For example, the second connecting portion 31 may be formed in the shape of an annular plate having a plurality of openings, or alternatively, in the shape of a plurality of radially extending arms. [Rotor]

[0047] The rotor 4 is supported by the rotor frame 2. In detail, the rotor 4 is supported by the first cylindrical portion 23 of the rotor frame 2. The rotor 4 rotates as a unit with the rotor frame 2. The rotor 4 is annular. The rotor 4 has a yoke 41 and a plurality of permanent magnets 42.

[0048] The yoke 41 has a cylindrical shape. The yoke 41 is fixed to the rotor frame 2. In detail, the yoke 41 is fixed 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.

[0049] The yoke 41 is fixed to the first cylindrical portion 23 at one end 41a, namely the end located on the second side in the axial direction. The yoke 41 protrudes from the first cylindrical portion 23 toward the second side in the axial direction. In other words, with the exception of the end 41a, the remaining portion of the yoke 41 is arranged radially outward. The yoke 41, together with the rotor frame 2 and the stator frame 3, forms an outer casing of the motor 100.

[0050] The permanent magnets 42 are fixed to the inner circumferential surface of the yoke 41. The permanent magnets 42 are spaced apart from each other in the circumferential direction. The permanent magnets are arranged radially outside the stator 5. In other words, the permanent magnets 42 are arranged to surround the stator 5. Note that the permanent magnets 42 are arranged radially at a distance from the stator 5. [Stator]

[0051] The stator 5 has a ring shape. The stator 5 is arranged radially inside the rotor 4. The stator 5 is arranged non-rotatably. 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. In other words, the stator 5 is arranged such that it encloses the third cylindrical portion 33. The stator 5 is supported by the third cylindrical portion 33.

[0052] The stator 5 has a stator core 51 and a plurality of coil sections 52. The stator core 51 is formed by laminating a plurality of electromagnetic steel plates as a plurality of layers.

[0053] The coil sections 52 are wound around the stator core 51. In detail, the coil sections 52 are wound around teeth of the stator core 51. Note that an insulating layer 53 is interposed between the coil sections 52 and the stator core 51. [Modifications]

[0054] A preferred embodiment of the present invention has been described above. However, the invention is not limited to this embodiment, but allows for various modifications within its scope, with the modifications to be described being simultaneously applicable.

[0055] (a) In the preferred embodiment described above, the receiving openings 241 are identical in terms of their opening area and depth. However, the rotor frame 2 is not limited to this configuration. The receiving openings 241 may also differ, in particular, in terms of their opening area.

[0056] For example in Fig. 3, the plurality of receiving openings 241 provided in each web 24 can be oriented so that their opening area decreases radially outward. Alternatively, the plurality of receiving openings 241 provided in each web 24 can be arranged so that their opening area increases radially outward.

[0057] On the other hand, the receiving openings 241 can differ from one another in terms of their depth. As for example in Fig. 5, the plurality of receiving openings 241 provided in each rib 24 may be arranged in a depth descending radially outward direction. As shown in Fig. 6, the receiving openings 241 provided in each rib 24 can be arranged so as to increase radially outward in depth.

[0058] (b) In the preferred embodiment described above, each receiving hole 241 is circular in the axial direction. However, the respective receiving holes 241 are not limited to this shape. For example, Fig. As shown in Figure 7, each receiving opening 241 may be formed in the form of an elongated hole extending in the radial direction. Each receiving opening 241 has a constant width along the radial direction. The term "width" here refers to the dimension of each receiving opening 241 in the circumferential direction.

[0059] It should be noted that the width of each receiving opening 241 may gradually decrease radially outward, as in Fig. 8. Alternatively, the width of each receiving opening 241 may gradually increase radially outward, as shown in Fig. 9 shown.

[0060] On the other hand, the depth of each receiving opening 241 can be constant or variable along the radial direction. As shown, for example, in Fig. 10, the depth of each receiving opening 241 may gradually decrease radially outward. As Fig. As shown in Figure 11, the depth of each receiving opening 241 may alternatively increase radially outward. (c) In the embodiment described above, the rotor frame includes the first cylindrical portion by which the rotor is supported. However, the rotor is not limited to this configuration and may be supported, for example, by the webs.

[0061] (d) In the embodiment described above, the engine 100 includes at least one balance weight 6. Optionally, the engine 100 may not include a balance weight 6, which is true if the engine 100 is a type of engine that does not require balance adjustment. LIST OF REFERENCE SYMBOLS 2 rotor frames 22 Inclined area 24 jetty 241 Receiving opening 4 Rotor 5 Stator 6 Counterweight 100 engine QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2023-223488

[0001]

Claims

[1] Engine, comprising: a rotor frame having a plurality of webs, each of the plurality of webs having a receiving opening, the plurality of receiving openings being arranged at intervals from one another in the circumferential direction, and the plurality of webs each extending in a radial direction; a rotor supported by the rotor frame and having a ring shape; and a stator arranged radially inside the rotor. [2] The engine of claim 1, further comprising: at least one counterweight arranged in at least one of the receiving openings. [3] The motor according to claim 1, wherein the plurality of webs each have a plurality of receiving holes arranged at intervals from each other in the radial direction. [4] Motor according to claim 3, wherein the receiving openings differ from each other in terms of their opening area. [5] The motor of claim 3, wherein the plurality of receiving openings are oriented radially outwardly descending in terms of their opening area. [6] The motor of claim 3, wherein the plurality of receiving openings are oriented radially outwardly ascending in terms of their opening area. [7] The motor of claim 3, wherein the plurality of receiving openings differ from each other in depth. [8] The motor of claim 3, wherein the plurality of receiving openings are oriented in a depth descending radially outward direction. [9] The motor of claim 3, wherein the plurality of receiving openings are arranged in radially outwardly ascending depth. [10] The motor according to claim 1, wherein each of the receiving openings has the shape of an elongated hole extending in the radial direction. [11] The motor of claim 10, wherein the width of each receiving opening gradually decreases radially outward. [12] The motor of claim 10, wherein the width of each receiving opening gradually increases radially outward. [13] The motor of claim 10, wherein the depth of each receiving opening gradually decreases radially outward. [14] The motor of claim 10, wherein the depth of each receiving opening gradually increases radially outward. [15] The motor of claim 1, wherein the rotor frame includes an upper plate portion and a slant portion, the upper plate portion being disc-shaped, the slant portion being disposed radially outside the upper plate portion and having an annular shape, and the receiving openings being disposed radially inside the slant portion.

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