Electric motors and ventilation fans

Abstract

To provide an electric motor and a fan in which, even in a case where the amount of a coil is increased due to use of an aluminum wire, the insulation distance between the coil and an enclosure can be ensured.SOLUTION: An electric motor includes a coil 7 that is formed by winding an aluminum wire, a core 6 on which the coil 7 is mounted in a circumferential direction, an insulation sheet 15 that covers a radially outer circumference of a coil end 7e of the coil 7 axially projecting from each end in an axial direction of the core 6, and an enclosure 5 that houses the coil 7, the core 6, and the insulation sheet 15.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present disclosure relates to an electric motor and a ventilation fan.

Background Art

[0002] In recent years, in order to reduce the cost of electric motors, aluminum wires, which are less expensive than copper wires, are used for coils. The aluminum used for aluminum wires has a lower conductivity than the copper used for copper wires. Therefore, in order to obtain the same electrical characteristics as those of copper wires using aluminum wires, it is necessary to make the cross-sectional area of the aluminum wire about 1.6 times that of the copper wire. For this reason, when a coil using an aluminum wire is housed in the outer shell of an electric motor when a copper wire is used for the coil, ensuring an insulation distance between the coil and the outer shell becomes a problem.

[0003] Patent Document 1 discloses a motor that insulates the periphery of a coil with an insulating sheet having a terminal block side portion disposed on the upper surface of the terminal block, a coil side portion disposed between a part in the radial direction of the coil and the inner surface of the motor outer shell, and a connecting portion that connects the terminal block side portion and the coil side portion.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The motor disclosed in Patent Document 1 arranges an insulating sheet so as to cover a portion where many coils with the largest coil end outer diameter overlap. Therefore, in a situation where aluminum wires are frequently used for coils, there has been a problem that an insulation distance between the coil winding and the outer shell cannot be ensured.

[0006] This disclosure aims to solve the above-mentioned problems and to provide an electric motor and a ventilation fan that can ensure sufficient insulation distance between the coil and the outer casing even when the amount of coil increases by using aluminum wire. [Means for solving the problem]

[0007] The electric motor according to this disclosure comprises a coil formed by winding aluminum wire, an iron core on which the coil is mounted circumferentially, an insulating sheet covering the radial outer circumference of the coil ends of the coil that protrude axially from both ends of the iron core in the axial direction, and an outer casing that houses the coil, the iron core, and the insulating sheet.

[0008] Furthermore, the ventilation fan described herein is equipped with the electric motor described herein. [Effects of the Invention]

[0009] According to this disclosure, by using aluminum wire, it is possible to obtain an electric motor and a ventilation fan that can ensure the insulation distance between the coil and the outer casing even when the amount of coil increases. [Brief explanation of the drawing]

[0010] [Figure 1] This is an exploded perspective view of the electric motor according to Embodiment 1. [Figure 2] This is a detailed top view of the stator according to Embodiment 1, as seen from the axial direction. [Figure 3] This is a detailed side view of the stator according to Embodiment 1, viewed from the radial direction, and is a detailed side view of the stator viewed from direction A in Figure 2. [Figure 4] This is a schematic cross-sectional view showing the configuration of the magnet wires that make up the stator coil according to Embodiment 1. [Figure 5] This is a detailed top view showing the stator according to Embodiment 1 with an insulating sheet wrapped around it, viewed from the axial direction. [Figure 6] This is an unfolded view of the insulating sheet according to Embodiment 1. [Figure 7]This is an explanatory diagram of the method for winding an insulating sheet around the stator coil according to Embodiment 1. [Figure 8] This is an explanatory diagram of the method for winding an insulating sheet around the stator coil according to Embodiment 1. [Figure 9] This is an unfolded view of the insulating sheet in Modification 1 of Embodiment 1. [Figure 10] This is an unfolded view of the insulating sheet in a modified example 2 of Embodiment 1. [Figure 11] This is a configuration diagram showing a ventilation fan equipped with an electric motor according to Embodiment 2. [Modes for carrying out the invention]

[0011] The embodiments for carrying out the subject matter of this disclosure will be described with reference to the attached figures. In each figure, the same or corresponding parts are denoted by the same reference numerals, and redundant explanations are simplified or omitted as appropriate. However, the subject matter of this disclosure is not limited to the following embodiments, and any modification of any component of the embodiments or omission of any component of the embodiments is possible without departing from the spirit of this disclosure.

[0012] Embodiment 1. The configuration of the electric motor 30 according to Embodiment 1 will be described with reference to Figures 1 to 5. Figure 1 is an exploded perspective view of the electric motor 30 according to Embodiment 1. Figure 2 is a detailed top view of the stator 1 according to Embodiment 1, viewed from the axial direction. In Figure 1, the insulating sheet 15 covering the coil end 7e of the coil 7 is not shown. Figure 3 is a detailed side view of the stator 1 according to Embodiment 1, viewed from the radial direction, and is a detailed side view viewed from direction A in Figure 2. In Figure 3, the insulating sheet 15 covering the coil end 7e of the coil 7 is not shown. Figure 4 is a schematic cross-sectional view showing the configuration of the magnet wire constituting the coil 7 of the stator 1 according to Embodiment 1. Figure 5 is a detailed top view of the stator 1 according to Embodiment 1, viewed from the axial direction, with the insulating sheet 15 wrapped around it. In the following description, the configuration of the electric motor 30 will be described using the direction of the arrows shown in Figure 1, but this is to facilitate understanding of the configuration of the electric motor 30 and does not limit the scope of this disclosure.

[0013] The electric motor 30 shown in Figure 1 is an inner rotor type. The stator 1 of the electric motor 30 has a circular opening in the axial direction indicated by axis A (sometimes called the rotation axis), which is the center of the stator 1. A rotor 2 that can rotate around the rotation axis is provided inside the circular opening of the stator 1. A shaft 3 is inserted in the axial direction into the center of the rotor 2 in the radial direction. Bearings 4a and 4b are attached to the shaft 3 so as to sandwich the rotor 2 in the axial direction. Bearings 4a and 4b are supported by outer casings 5a and 5b, respectively. The outer casings 5a and 5b are fixed to each other using fasteners not shown, such as screws. The stator 1 and rotor 2 are housed inside the outer casings 5a and 5b. One end of the shaft 3 protrudes outwards in the axial direction from a hole opening in the center of the outer casing 5a in the radial direction and is connected to a load such as blades. Note that the outer casings 5a and 5b are sometimes collectively referred to as the outer casing 5.

[0014] As shown in FIGS. 2 and 3, the stator 1 has a core 6, a coil 7, and an insulator 8. The coil 7 is composed of coils 7a, 7b, 7c, and 7d. The insulator 8 is, for example, insulating paper. In Embodiment 1, as an example, a 12-phase 4-pole stator 1 is shown.

[0015] The core 6 has 24 teeth 13 protruding toward the radial center and slots 9 formed between adjacent teeth 13. The core 6 is formed by caulking thin plates laminated in the axial direction within a mold. The core 6 has a notch portion 14 in which a part of the outer periphery in the radial direction is cut out. In Embodiment 1, the notch portion 14 has notch portions 14a and 14b. The notch portion 14a is provided at two opposed locations having an equal distance in the radial direction from the central axis A. The core 6 is provided with two notch portions 14b at positions spaced 90° in the circumferential direction from each notch portion 14a.

[0016] As shown in FIG. 2, the width of the notch portion 14 (14a, 14b) has an angle of about 30° in the radial direction with respect to the axis A which is the rotation axis. The width of the notch portion 14 corresponds to the width of two teeth in the case of 24 slots and 24 teeth as in Embodiment 1. The notch portion 14 is used as a fixing portion for fixing the stator 1 with a jig when winding the coil 7 around the stator 1. In Embodiment 1, two notch portions 14a and two 14b are shown, but only two notch portions 14a may be provided.

[0017] As shown in FIG. 4, the magnet wire as the aluminum wire used for the coil 7 (7a, 7b, 7c, 7d) is composed of a conductor 10 mainly made of aluminum and an enamel insulation coating 11 baked on the outer periphery of the conductor 10.

[0018] As the winding method of the coil 7 around the core 6, there are distributed winding or concentrated winding. Here, distributed winding will be described as an example, but concentrated winding is similarly applicable.

[0019] As shown in Figures 2 and 3, the coil 7 is mounted in the slot 9 so as to straddle multiple teeth 13 of the iron core 6. Coil 7 has coils 7a and 7b on the radially outer side, and coils 7c and 7d inside coils 7a and 7b. Coils 7a and 7b are positioned with coil 7a on the axial side and coil 7b inside coil 7a. Similarly, coils 7c and 7d are positioned with coil 7c on the axial side and coil 7d inside coil 7c. Coils 7a, 7b, 7c, and 7d are each provided at four locations in the circumferential direction. Furthermore, coils 7a and 7b, and coils 7c and 7d are positioned at 45° offsets in the circumferential direction. Coil 7 also has a portion that protrudes axially from the axial end of the iron core 6, as shown in the coil end 7e in Figure 3. The coil end 7e protrudes axially from both ends of the iron core 6 in the axial direction. In distributed windings, the coil end 7e protrudes more axially from the axial end of the core 6 than in concentrated windings. Also, the radial outer diameter of coil 7 (D1 in Figure 7) is smaller than the outer diameter of core 6.

[0020] The insulator 8 insulates the iron core 6 from the coil 7. As shown in Figures 2 and 3, the insulator 8 is located between the iron core 6 and the coil 7 and is provided along the inner surface of the slot 9. The insulator 8 protrudes axially from the axial end of the iron core 6, as shown in the cuff portion 8a in Figure 3. The cuff portion 8a protrudes axially from both axial ends of the iron core 6. The height of the cuff portion 8a in the axial direction is lower than the height of the coil end 7e.

[0021] The stator 1 further includes an insulating sheet 15. As shown in Figure 5, the insulating sheet 15 is provided to cover the radial outer circumference of the coil 7. More specifically, the insulating sheet 15 is provided to cover the outer circumference of the coil ends 7e, which protrude axially from both ends of the iron core 6 in the axial direction, by encircling the outer circumference of the coil ends 7e.

[0022] Next, with reference to Figures 6 to 8, the method of winding the insulating sheet 15 around the coil 7 of the stator 1 will be described. Figure 6 is an unfolded view of the insulating sheet 15 according to Embodiment 1. Figures 7 and 8 are explanatory diagrams of the method of winding the insulating sheet 15 around the coil 7 of the stator 1 according to Embodiment 1.

[0023] As shown in Figure 6, the insulating sheet 15 has a first outer peripheral portion 15b and a second outer peripheral portion 15c that cover the outer circumference of the coil ends 7e in the radial direction, which protrude axially from both ends of the iron core 6 in the axial direction. The first outer peripheral portion 15b and the second outer peripheral portion 15c are strip-shaped so as to be wrapped around the outer circumference of the coil ends 7e. The insulating sheet 15 also has a connecting portion 15a that connects the first outer peripheral portion 15b and the second outer peripheral portion 15c. The insulating sheet 15 has a Z-shape, with one end 15d of the first outer peripheral portion 15b and one end 15f of the second outer peripheral portion 15c connected by the connecting portion 15a.

[0024] As shown in Figures 6 and 7, in the insulating sheet 15, the width W1 of the connecting portion 15a is set to be shorter than the width W3 of the notched portion 14a. The height H1 of the connecting portion 15a is set to be the same as or longer than the height H5 of the iron core 6. Furthermore, in order to ensure insulation distance, the height H1 of the connecting portion 15a is set so that the cuff portion 8a and the first outer circumference 15b, and the cuff portion 8a and the second outer circumference 15c, overlap each other by 3 mm or more in the axial direction.

[0025] Furthermore, in the insulating sheet 15, the width W2 of the first outer periphery 15b and the second outer periphery 15c is set to a dimension that is 3 mm or more added to the outer periphery dimension of the coil end 7e in the circumferential direction. Specifically, when the diameter of the coil end 7e is D1, the width W2 of the first outer periphery 15b and the second outer periphery 15c has the relationship W2 ≥ (π × diameter D1 of the coil end 7e) + 3 mm. In addition, the axial height H2 of the first outer periphery 15b and the second outer periphery 15c should be at least the height H3 of the coil end 7e, but for more stable insulation, it is desirable to set it to a dimension that is 3 mm or more added to the height H3 of the coil end 7e (H3 + H4 in Figure 7).

[0026] First, as shown in Figure 7, the insulating sheet 15 is fixed at its connecting portion 15a to the notch 14a of the iron core 6. The connecting portion 15a to the notch 14a can be fixed using, for example, an adhesive. The connecting portion 15a is positioned so that the first outer peripheral portion 15b and the second outer peripheral portion 15c of the insulating sheet 15 can be wrapped around the outer circumference of the coil end 7e. By fixing the connecting portion 15a of the insulating sheet 15 to the notch 14a in this way, the insulating sheet 15 is positioned. Therefore, the first outer peripheral portion 15b and the second outer peripheral portion 15c can be wrapped around the outer circumference of the coil end 7e with high precision.

[0027] Subsequently, the first outer circumference 15b of the insulating sheet 15 is wrapped around the outer circumference of the coil end 7e, which includes the insulator 8, as shown by arrow S in Figure 8. Similarly, the second outer circumference 15c of the insulating sheet 15 is wrapped around the outer circumference of the coil end 7e, which includes the insulator 8. The direction in which the second outer circumference 15c is wrapped around the coil end 7e is opposite to the direction of arrow S shown in Figure 8 (clockwise direction in Figure 8) (counterclockwise direction in Figure 8).

[0028] Finally, the first outer circumference portion 15b, which is wound around the outer circumference of the coil end 7e, is fixed by bonding together, for example, an adhesive, at the overlapping portion (part V shown in Figure 5) between one end 15d, which is the starting point of the winding, and the other end 15e, which is the ending point of the winding. Similarly, the second outer circumference portion 15c, which is wound around the outer circumference of the coil end 7e, is fixed by bonding together, for example, an adhesive, at the overlapping portion between one end 15f, which is the starting point of the winding, and the other end 15g, which is the ending point of the winding. It is desirable that the overlapping portions of one end 15d and the other end 15e of the first outer circumference portion 15b, and the overlapping portions of one end 15f and the other end 15g of the second outer circumference portion 15c, be 3 mm or more in order to ensure an insulating distance. With this, the stator 1 is completed.

[0029] In Embodiment 1, a Z-shaped insulating sheet 15 as shown in Figures 6 and 7 was used for the explanation, but the insulating sheet 15 can be any shape that can cover the radial outer circumference of the coil end 7e. For example, the insulating sheet 15 may be a U-shape as shown in Figure 9, or an H-shape as shown in Figure 10. The U-shaped and H-shaped insulating sheets 15 differ from the Z-shaped insulating sheet 15 in the position of the connecting portion 15a to the first outer circumference 15b and the second outer circumference 15c, but they can cover the radial outer circumference of the coil end 7e.

[0030] As described above, according to Embodiment 1, since the insulating sheet 15 is arranged to surround and cover the outer circumference in the radial direction of the coil end 7e, an electric motor 30 can be obtained that can secure the insulation distance between the coil 7 and the outer casing 5 even when the amount of aluminum wire used for the coil 7 is increased.

[0031] Furthermore, even when using aluminum wire, the insulation distance can be maintained even when the spatial distance between the coil 7 and the outer casing 5 is reduced, thus contributing to the miniaturization of the electric motor 30. This miniaturization also contributes to reducing the cost of the electric motor 30.

[0032] Furthermore, since an insulating distance can be ensured between the coil 7 and the outer casing 5, inexpensive aluminum wire can be actively used. This contributes to reducing the cost of the electric motor 30.

[0033] Furthermore, since a notch 14a is provided for fixing the connecting portion 15a of the insulating sheet 15, the first outer circumference 15b and the second outer circumference 15c can be precisely wrapped around the outer circumference of the coil end 7e.

[0034] Embodiment 2. Figure 11 is a configuration diagram showing a ventilation fan 21 equipped with an electric motor 30 according to Embodiment 1. Figure 11 shows the ventilation fan 21 viewed from the rear. As shown in Figure 11, the ventilation fan 21 comprises a rectangular main frame 22, an air duct 23 provided on the rear of the main frame 22, four support legs 24 rising from the four corners of the main frame 22 to the rear, and an electric motor case 26 provided at the tips of the four support legs 24. Each support leg 24 has a mounting portion 24a at its base end, and the mounting portion 24a of each support leg 24 is fixed to the four corners of the main frame 22 with bolts. The ventilation fan 21 also includes an impeller 25 fixed to the shaft 3 of the electric motor 30, which is fixed inside the electric motor case 26, and which rotates in the air duct 23 when driven by the electric motor 30. The ventilation fan 21 configured in this way is installed on the wall of a building (not shown) and ventilates the room by exhausting indoor air, or introduces outside air into the room by drawing in outside air.

[0035] As described above, according to Embodiment 2, the electric motor 30 shown in Embodiment 1 is provided in the ventilation fan 21. The electric motor 30 can be made more cost-effective, and as a result, the cost of the ventilation fan 21 can be reduced.

[0036] The configurations shown in the embodiments described above are merely examples of the content of this disclosure. The embodiments can be combined with other known technologies. Some parts of the configurations of the embodiments can be omitted or modified without departing from the gist of this disclosure.

[0037] Examples of aspects that may be included in this disclosure are listed below as an addendum. (Note 1) A coil formed by winding aluminum wire, The aforementioned coil is mounted circumferentially on an iron core, An insulating sheet covering the radial outer circumference of the coil ends of the coil that protrude in the axial direction from both ends of the iron core in the axial direction, The outer casing housing the coil, the iron core, and the insulating sheet, An electric motor equipped with [a specific feature]. (Note 2) An insulator is provided between the coil and the iron core and has a cuff portion that covers a part of the coil end, The insulating sheet covers the cuff portion. Electric motor as described in Appendix 1 (Note 3) The insulating sheet comprises a first outer peripheral portion and a second outer peripheral portion that cover the radial outer circumference of the coil ends protruding in the axial direction from both ends of the iron core in the axial direction, and a connecting portion that connects the first outer peripheral portion and the second outer peripheral portion. The electric motor described in Appendix 1. (Note 4) The iron core has a notch for fixing the connecting portion. The electric motor described in Appendix 3. (Note 5) Equipped with an electric motor as described in any one of the appendices 1 to 4, Ventilation fan. [Explanation of symbols]

[0038] 1 Stator, 2 Rotor, 3 Shaft, 4a Bearing, 4b Bearing, 5 Outer casing, 5a Outer casing, 5b Outer casing, 6 Iron core, 7 Coil, 7a Coil, 7b Coil, 7c Coil, 7d Coil, 7e Coil end, 8 Insulator, 8a Cuff, 9 Slot, 10 Conductor, 11 Enamel insulating coating, 13 Teeth, 14 Notch, 14a Notch, 14b Notch, 15 Insulating sheet, 15a Connecting part, 15b First outer circumference, 15c Second outer circumference, 15d One end, 15e Other end, 15f One end, 15g Other end, 21 Ventilation fan, 22 Main frame, 23 Wind tunnel, 24 Support legs, 24a Mounting part, 25 Impeller, 26 Motor case, 30 Motor.

Claims

1. A coil formed by winding aluminum wire, The aforementioned coil is mounted circumferentially on an iron core, An insulating sheet covering the radial outer circumference of the coil ends of the coil that protrude in the axial direction from both ends of the iron core in the axial direction, The outer casing housing the coil, the iron core, and the insulating sheet, Equipped with, The insulating sheet comprises a first outer peripheral portion and a second outer peripheral portion that cover the radial outer circumference of the coil ends protruding in the axial direction from both ends of the iron core in the axial direction, and a connecting portion that connects the first outer peripheral portion and the second outer peripheral portion. The iron core has a notch for fixing the connecting portion. Electric motor.

2. An insulator is provided between the coil and the iron core and has a cuff portion that covers a part of the coil end, The insulating sheet covers the cuff portion. The electric motor according to claim 1.

3. A motor comprising the electric motor according to claim 1 or 2, Ventilation fan.

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