Rotating electric machine

Abstract

The goal is to improve the cooling of the stator. [Solution] The rotating electric machine is characterized by having a stator having stator fins on its radially outward side, a rotor disposed radially inward of the stator portion with a gap in between, and a cowl that guides air to the stator fins.

Description

Technical Field

[0001] The present invention relates to a rotating electrical machine.

Background Art

[0002] Conventionally, structures for cooling rotating electrical machines have been studied. The rotating electrical machine described in Patent Document 1 discloses a structure in which, in a stator disposed radially outward of a rotor, a stator core is formed to have heat radiation fins on a radially outer side, and the heat radiation fins are exposed to the radially outer side to directly radiate heat to open air.

Prior Art Literature

Patent Literature

[0003]

Patent Document 1

Summary of Invention

Problem to be Solved by the Invention

[0004] In Patent Document 1, although the stator can be cooled by air impinging on the heat radiation fins, no study has been made on a structure that actively directs air to the heat radiation fins, so there is room for improvement in cooling of the stator.

[0005] The present invention has been made in view of the above points, and an object of the present invention is to improve cooling of a stator.

Means for Solving the Problem

[0006] A rotating electrical machine according to one aspect of the present invention includes: a stator having stator fins on a radially outer side; a rotor disposed radially inward of the stator portion via a gap; and a cowl that guides air to the stator fins.

Effect of the Invention

[0007] According to one aspect of the present invention, stator cooling can be improved. [Brief explanation of the drawing]

[0008] [Figure 1] This is a perspective view of the motor 100 according to Embodiment 1 of the present invention. [Figure 2] This is an exploded perspective view of motor 100. [Figure 3] This is a diagram showing the stator section 170. [Figure 4] This diagram shows a drone flying using motor 100 as its power source. [Figure 5] This is a diagram illustrating the effect of cowl 173. [Figure 6] This is a perspective view of a motor 1100 according to Embodiment 2 of the present invention. [Figure 7] This is a perspective view of a motor 2100 according to Embodiment 3 of the present invention. [Modes for carrying out the invention]

[0009] The following description of a rotating electric machine according to an embodiment of the present invention will be made with reference to the drawings. Note that in the following drawings, the scale and number of components in each structure may differ from the actual structure in order to make the components easier to understand.

[0010] <Embodiment 1> Figure 1 is a perspective view of a motor 100 according to Embodiment 1 of the present invention. Figure 2 is an exploded perspective view of the motor 100. The motor 100 is a radial gap motor and is an example of a rotating electric machine. The motor 100 rotates with a shaft 130 extending along the central axis J as its axis of rotation.

[0011] Furthermore, in the drawings, the XYZ coordinate system is shown as a three-dimensional Cartesian coordinate system where appropriate. In the XYZ coordinate system, the Z-axis direction is parallel to the axis direction of the central axis J shown in Figure 1. The X-axis direction is the radial direction relative to the central axis J as shown in the illustration. The Y-axis direction is perpendicular to both the X-axis and Z-axis directions. In all of the X-axis, Y-axis, and Z-axis directions, the side indicated by the arrow in the figure is the + side, and the opposite side is the - side.

[0012] Furthermore, in the following explanation, the positive side in the Z-axis direction (+Z side) will be referred to as "one side," and the negative side in the Z-axis direction (-Z side) will be referred to as "the other side." Note that "one side" and "the other side" are merely names used for explanatory purposes and do not limit the actual positional relationship or direction. Unless otherwise specified, the direction parallel to the central axis J (Z-axis direction) will be simply referred to as the "axis direction," the radial direction centered on the central axis J will be simply referred to as the "radial direction," and the circumferential direction centered on the central axis J, i.e., around the axis of the central axis J, will be simply referred to as the "circumferential direction." In the radial direction, the side approaching the central axis J will be referred to as the "inside radial direction," and the side moving away from the central axis J will be referred to as the "outside radial direction." In the circumferential direction, the clockwise side when viewed from the +Z side to the -Z side will be referred to as the "one side circumferential," and the counterclockwise side will be referred to as the "other side circumferential."

[0013] In this specification, "extending in the axial direction" includes not only cases where the material extends strictly in the axial direction, but also cases where the material extends in a direction inclined to the axial direction by an angle of less than 45°. Furthermore, in this specification, "extending radially" includes not only cases where the material extends strictly radially, i.e., perpendicular to the axial direction, but also cases where the material extends in a direction inclined to the radial direction by an angle of less than 45°. Furthermore, "parallel" includes not only cases where the material is strictly parallel, but also cases where the angle between the material and the material is inclined to each other by an angle of less than 45°. Furthermore, "spreading in a direction perpendicular to the axial direction" includes not only cases where the material spreads in a direction perpendicular to the axial direction, but also cases where the material spreads in a direction inclined to the direction perpendicular to the axial direction by an angle of less than 45°.

[0014] The motor 100 comprises a bracket 110, a bearing 120, a shaft 130, an end plate 140, a magnet 150, a rotor core 160, a stator portion 170, an end plate 180, a bearing 190, and a bracket 200.

[0015] In the stator portion 170, the bracket 200 is fixed to one axial side, and the bracket 110 is fixed to the other axial side. The bracket 110 and the bracket 200 are fastened by a fastening member including, for example, a hexagon nut and a hexagon bolt. The bracket 110 and the bracket 200 may be fixed by welding. A radially outer portion of the stator portion 170 is exposed radially outward from a position between the bracket 110 and the bracket 200 in the axial direction.

[0016] The rotor core 160, to which the magnet 150 serving as a rotor magnet is fixed, has the end plate 180 fixed to one axial side and the end plate 140 fixed to the other axial side, and constitutes a rotor portion of the motor 100. The stator portion 170 is disposed radially outside the rotor core 160 via a gap. The shaft 130 is fixed to a center hole of the rotor core 160. The shaft 130 is pivotally supported in the center holes of the bracket 110 and the bracket 200 by the bearing 120 and the bearing 190.

[0017] Figure 3 is a view showing the stator portion 170, wherein Figure 3(A) is a perspective view of the stator portion 170, and Figure 3(B) is a perspective view of the stator core 171. The stator portion 170 is configured by winding a winding wire 172, which is a stator coil, around the stator core 171, and disposing a cowl 173 on an outer circumference of the stator core 171. In the motor 100, when a current flows through the winding wire 172, the shaft 130 fixed to the rotor core 160 rotates around a central axis J.

[0018] The stator core 171 includes an annular core back portion 171a, a tooth portion 171b protruding radially inward from an inner circumference of the core back portion 171a, and a fin 171c protruding radially outward from an outer circumference of the core back portion 171a. A plurality of the fins 171c are provided in a circumferential direction. The fin 171c is an example of a stator fin. The stator core 171 is formed of a laminated steel plate obtained by laminating flat electromagnetic steel sheets in an axial direction. The cowl 173 is a resin member, which is produced by overmolding with the stator core 171, and the radially outer portion of the fin 171c is coupled to the cowl 173.

[0019] The cowl 173 includes a cylindrical portion 173a having an inner circumference coupled to the radially outer portion of the fin 171c, and a tapered portion 173b expanding toward one axial side from one axial end of the cylindrical portion 173a. The tapered portion 173b is inclined such that a radial position on one axial side is located more radially outward than a radial position on the other axial side.

[0020] Figure 4 is a view showing a drone that flies using a motor 100 as a driving source, wherein Figure 4(A) is a perspective view of the drone 300 using the motor 100 as a driving source, and Figure 4(B) is an enlarged cross-sectional view showing a range A of the drone 300 shown in Figure 4(A).

[0021] The drone 300 includes the motor 100 and a propeller 210 fixed to one axial end of a shaft 130. The drone 300 flies by generating buoyancy through rotation of the propeller 210 accompanying rotation of the shaft 130. Rotation of the propeller 210 generates airflow traveling from one axial side toward the other axial side. Among the airflow generated by rotation of the propeller 210, the cowl 173 concentrates, onto the fins 171c by the tapered portion 173b, the airflow that passes through a region located radially outward of the radial position of the fins 171c. The cowl 173 guides airflow to the fins 171c.

[0022] Figure 5 is a view for explaining the effect of the cowl 173, wherein Figure 5(A) is a schematic cross-sectional view showing airflow when the cowl 173 is not provided, and Figure 5(B) is a schematic cross-sectional view showing airflow when the cowl 173 is provided.

[0023] As shown in Figure 5(A), when the cowl 173 is not provided, the airflow from the propeller 210 is axial, and the air passing radially outside the radial position of the fin 171c does not hit the fin 171c. On the other hand, as shown in Figure 5(B), when the cowl 173 is provided, the tapered portion 173b concentrates the air passing radially outside the radial position of the fin 171c onto the fin 171c. Therefore, by providing the cowl 173, more air hits the fin 171c compared to when the cowl 173 is not provided, and the heat dissipation effect of the fin 171c can be further improved.

[0024] Furthermore, according to the motor 100 of Embodiment 1, the heat from the stator core 171 is transferred to the cowl 173 via the fins 171c, and heat is also dissipated from the cowl 173. The heat dissipation effect can be further improved by the air blowing on the tapered portion 173b.

[0025] <Embodiment 2> Figure 6 is a perspective view of the motor 1100 according to Embodiment 2 of the present invention. In Embodiment 2, components similar to those in Embodiment 1 are denoted by the same reference numerals and detailed descriptions are omitted. The motor 1100 has a cowl 1173 instead of the cowl 173 of Embodiment 1.

[0026] The cowl 1173 is a resin component manufactured by overmolding with the stator core 171, and the radially outer portion of the fin 171c is joined to the cowl 1173. The cowl 1173 has a cylindrical portion 1173a whose inner circumference is joined to the radially outer portion of the fin 171c, and a tapered portion 1173b that extends axially from one end of the cylindrical portion 1173a toward the other axial side. The tapered portion 1173b has an inclination such that the radial position on one axial side is located further radially outward than the radial position on the other axial side.

[0027] Furthermore, the tapered portion 1173b has fins 1173ba that protrude radially inward from the radially inward surface. Multiple fins 1173ba are provided in the circumferential direction. Fins 1173ba are an example of cowl fins.

[0028] According to Embodiment 2, since the cowl 1173 has fins 1173ba, the surface area of ​​the cowl 1173 is larger than that of the cowl 173, and heat is also dissipated from the fins 1173ba. The wind generated by the rotation of the propeller 210 hits the fins 1173ba, which can further improve the heat dissipation effect of the stator core 171.

[0029] <Embodiment 3> Figure 7 is a perspective view of the motor 2100 according to Embodiment 3 of the present invention. In Embodiment 3, components similar to those in Embodiment 1 are denoted by the same reference numerals and detailed descriptions are omitted. The motor 2100 has a cowl 2173 instead of the cowl 173 of Embodiment 1.

[0030] The cowl 2173 is a resin component manufactured by overmolding with the stator core 171, and the radially outer portion of the fin 171c is joined to the cowl 2173. The cowl 2173 has a cylindrical portion 2173a whose inner circumference is joined to the radially outer portion of the fin 171c, and a tapered portion 2173b that extends axially from one end of the cylindrical portion 2173a toward the other axial side. The tapered portion 2173b has an inclination such that the radial position on one axial side is located further radially outward than the radial position on the other axial side. The tapered portion 2173b also has fins 2173ba that protrude radially inward from the radially inner surface. Multiple fins 2173ba are provided in the circumferential direction.

[0031] Furthermore, the cowl 2173 has ribs 2173bb that connect the radially outer surface of the tapered portion 2173b and the radially outer surface of the cylindrical portion 2173a. Multiple ribs 2173bb are provided in the circumferential direction.

[0032] Bending stress is generated in the tapered section 2173b due to the wind produced by the rotation of the propeller 210. However, according to Embodiment 3, since the cowl 2173 has ribs 2173bb, the tapered section 2173b can be supported by the ribs 2173bb fixed to the cylindrical section 2173a. This prevents the tapered section 2173b from oscillating.

[0033] The present invention is not limited to the embodiments described above, and various improvements and design modifications may be made without departing from the spirit of the invention. In addition, the embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than the above description, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of Symbols]

[0034] 100...motor 110, 200... bracket 120, 190... bearings 130… Shaft 140, 180...end plate 150...Magnet 150 160... Rotor core 170... Stator section

Claims

1. A stator having stator fins on the radially outward side, A rotor is positioned radially inward of the stator portion with a gap in between, A cowl that guides air to the stator fins, A rotating electric machine characterized by having the following features.

2. The cowl has cowl fins positioned where it is exposed to the wind. The rotating electric machine according to feature 1.

3. The cowl has ribs that reinforce the cowl. The rotating electric machine according to feature 1.

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