Electric motor and method for manufacturing electric motor

Abstract

The present invention provides an electric motor and a method for manufacturing the electric motor. The electric motor (10) comprises: a shaft (12); and a stator (16) which is arranged on the outer periphery of the shaft (12) and has a plurality of slots (18) extending toward the shaft (12), and a coil portion (20) composed of a plurality of wires (26) connected in parallel is arranged for each of the plurality of slots (18), wherein the coil portion (20) arranged in at least one of the plurality of slots (18) formed in the stator (16) has a plurality of winding groups (24) connected in series and having different numbers of turns, and the plurality of winding groups (24) are arranged in the slots (18) in the order of the number of turns from large to small along the direction toward the shaft (12).

Description

Technical Field

[0001] The present invention relates to an electric motor and a method for manufacturing the electric motor. Background Art

[0002] As a general structure of an electric motor, it is known that a slot is formed in a stator and a coil portion is provided in the slot. For example, an example of such an electric motor is disclosed in Japanese Patent Gazette No. 2018-157753. According to the disclosure, the coil portion (unit coil) has a plurality of winding groups (coil groups), and the plurality of winding groups can be provided relative to one slot. Summary of the invention

[0003] In the motor having the above structure, represented by the technology disclosed in Japanese Patent Application Laid-Open No. 2018-157753, leakage flux is generated in the coil portion provided in the slot, which causes the deviation of the inductance of the coil portion.

[0004] Therefore, an object of the present invention is to provide a motor and a method for manufacturing the motor that can reduce the variation in inductance of a coil portion caused by leakage magnetic flux.

[0005] One embodiment of the invention is an electric motor comprising: a shaft; and a stator, which is arranged on the outer periphery of the above-mentioned shaft and has a plurality of slots extending toward the above-mentioned shaft, and a coil portion composed of a plurality of wires connected in parallel is provided for each of the plurality of the above-mentioned slots, wherein the coil portion provided in at least one of the plurality of the above-mentioned slots formed in the above-mentioned stator has a plurality of winding groups connected in series and having different numbers of turns, and the plurality of the above-mentioned winding groups are arranged in the above-mentioned slots in the order of the number of turns from large to small along the direction toward the above-mentioned shaft.

[0006] Another embodiment of the invention is a method for manufacturing an electric motor, the electric motor comprising: a shaft; and a stator, which is arranged on the outer periphery of the shaft and has a plurality of slots extending toward the shaft, the method for manufacturing the electric motor comprising: a first step of forming a coil portion composed of a plurality of wires connected in parallel into a plurality of winding groups connected in series and having different numbers of turns; and a second step of arranging the plurality of winding groups in at least one of the plurality of slots formed in the stator in an order of the number of turns from large to small along a direction toward the shaft.

[0007] According to the present invention, it is possible to provide a motor and a method for manufacturing a motor that can reduce variations in the inductance of a coil portion due to leakage magnetic flux.

[0008] The above objects, features and advantages will be easily understood from the following description of the embodiments with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1It is a cross-sectional view of the electric motor according to this embodiment.

[0010] Figure 2 It is a diagram for explaining the slot and the coil unit according to the present embodiment.

[0011] Figure 3 yes Figure 2 Cross-sectional view along line III-III.

[0012] Figure 4 This is a flowchart showing an example of the method for manufacturing the electric motor according to the present embodiment.

[0013] Figure 5A This is a diagram for explaining a conventional coil portion in which the inductance is unstable. Figure 5B It is a diagram for explaining the coil unit according to the present embodiment. DETAILED DESCRIPTION

[0014] Hereinafter, the preferred embodiments of the electric motor and the method for manufacturing the electric motor of the present invention will be described with reference to the accompanying drawings. Figure 1 Explain in detail.

[0015] [Implementation Method]

[0016] The electric motor 10 of the present embodiment includes a shaft 12 as a rotating shaft, a rotor 14 attached to the shaft 12 , and a stator 16 .

[0017] The shaft 12 and the rotor 14 can be configured based on known techniques in the present embodiment, and therefore, detailed descriptions of the shaft 12 and the rotor 14 will be omitted below.

[0018] Figure 1 : is a cross-sectional view of the electric motor 10 of this embodiment. Figure 1 The line of sight is the axial direction of the shaft 12.

[0019] The stator 16 is a substantially cylindrical member provided on the outer periphery of the shaft 12 and the rotor 14. Figure 1 In FIG. 1 , the approximate positions where the shaft 12 and the rotor 14 are arranged are indicated by dotted lines. The stator 16 of the present embodiment has a substantially cylindrical shape, but the shape of the stator 16 is not limited thereto, and may have a square cylindrical shape, for example.

[0020] A plurality of slots 18 are formed along the axial direction of the shaft 12 on the inner circumference of the cylindrical stator 16. The plurality of slots 18 are radially arranged so as to extend toward the shaft 12 when the stator 16 is arranged on the outer circumference of the shaft 12. Coil portions 20 to which current is supplied when the shaft 12 rotates are respectively arranged in the plurality of slots 18.

[0021] Figure 21 is a diagram for explaining the slot 18 and the coil unit 20 of the present embodiment. Figure 2 This is an enlarged perspective view of a part of the stator 16 according to the present embodiment.

[0022] The coil portion 20 is formed by connecting a plurality of winding groups 24 in series with each other, in which the wiring 22 is wound in a substantially spiral shape with a predetermined number of turns. The wiring 22 is formed by bundling a plurality of wires 26 and connecting them in parallel with each other. The wires 26 constituting the wiring 22 can use general enameled wires. The number of turns of the coil portion 20 is not particularly limited, and in this embodiment, as an example, 10 turns.

[0023] The plurality of winding groups 24 included in one coil portion 20 include two or more winding groups 24 having different numbers of turns, and are provided in the slots 18 in order from the winding group having the largest number of turns along the direction toward the axis 12 .

[0024] Hereinafter, the third winding group 24 disposed in one slot 18 will be referred to as the first winding group 24A, the second winding group 24B, and the third winding group 24C in descending order from the axis 12 .

[0025] In the present embodiment, the number of turns of the first winding group 24A is set to 5 turns, the number of turns of the second winding group 24B is set to 3 turns, and the number of turns of the third winding group 24C is set to 2 turns. In addition, the number of turns of the first winding group 24A, the second winding group 24B, and the third winding group 24C are not limited to the above. For example, the number of turns of the first winding group 24A may be set to 4 turns, the number of turns of the second winding group 24B may be set to 3 turns, and the number of turns of the third winding group 24C may be set to 3 turns.

[0026] Figure 3 yes Figure 2 Cross-sectional view along line III-III.

[0027] The motor 10 of the present embodiment further includes an insulating member 28 that separates the plurality of winding groups 24 adjacent to each other in the direction toward the shaft 12 in the slot 18. This prevents unexpected electrical interference between the plurality of winding groups 24 in the slot 18.

[0028] The insulating member 28 is an insulating member (insulating member), such as a thin film of insulating paper, insulating film or insulating tape. The insulating member 28 is provided in the slot 18 so as to extend in the axial direction of the shaft 12. In addition, the insulating member 28 is provided between the plurality of winding groups 24, such as Figure 3 As shown, it is preferably arranged in a manner that blocks direct contact between the wire 26 and the inner surface of the slot 18 .

[0029] Figure 4 This is a flowchart showing an example of a method for manufacturing the electric motor 10 according to the present embodiment.

[0030] Hereinafter, a method for manufacturing the electric motor 10 having the above-mentioned structure (hereinafter, simply referred to as a manufacturing method) will be described. The manufacturing method includes a first step and a second step. Hereinafter, the steps will be described in order.

[0031] In the first step, the coil portion 20 composed of a plurality of wires 26 connected in parallel is formed to have a plurality of winding groups 24 connected in series and having different numbers of turns.

[0032] The first step includes a wiring forming step of forming the wiring 22 in which a plurality of wires 26 are connected in parallel, and a winding group forming step of forming a plurality of winding groups 24 by spirally winding the wiring 22 .

[0033] The wiring forming step can be performed by bundling a plurality of wires 26. As described above, general enameled wires can be used as the wires 26. The number of wires 26 to be bundled is not particularly limited, but is preferably the same for all coil units 20 provided in the motor 10.

[0034] The winding group forming step can be easily performed by using a bobbin for winding the wiring 22. That is, in the winding group forming step, the first winding group 24A can be easily formed by winding the wiring 22 around the bobbin for 5 turns. Then, the second winding group 24B can be easily formed by winding the portion of the wiring 22 that is not wound as the first winding group 24A for 3 turns. Similarly, the third winding group 24C can be easily formed by winding the remaining portion of the wiring 22 for 2 turns.

[0035] The first step can form the coil unit 20 having a plurality of winding groups 24 connected in series. The coil unit 20 can be prepared in the same number as the slots 18 formed in the stator 16 at most.

[0036] In the second step, a plurality of winding groups 24 are sequentially arranged in a direction toward the axis 12 so that the number of turns decreases in each of all the slots 18 formed in the stator 16. The method of obtaining the stator 16 having a plurality of slots 18 can be based on a known technique, and thus the description thereof is omitted here.

[0037] The second step includes: a winding group inserting step of placing one of the plurality of winding groups 24 in the slot 18 ; and an insulating member inserting step of placing the insulating member 28 between the plurality of winding groups 24 adjacent to each other in the direction toward the axis 12 .

[0038] In the winding group inserting step, the winding group 24 with the largest number of turns among the plurality of winding groups 24 not set in the slot 18 is selected and set in the slot 18. In the insulating member inserting step, the insulating member 28 is set in the slot 18 in a manner adjacent to the winding group 24 inserted into the slot 18 in the winding group inserting step in the direction toward the axis 12.

[0039] The winding group inserting step and the insulating member inserting step may be repeatedly performed until a predetermined number (three in the present embodiment) of winding groups 24 are set in the slots 18 .

[0040] In addition, the winding group inserting step and the insulating member inserting step can be performed for each of the plurality of slots 18. Thus, for all the slots 18, a structure can be obtained in which the first winding group 24A, the insulating member 28, the second winding group 24B, the insulating member 28, and the third winding group 24C are sequentially arranged in the direction toward the axis 12. That is, for all the slots 18 of the stator 16, a structure can be obtained in which the plurality of winding groups 24 are sequentially arranged in the direction toward the axis 12 in a decreasing order of the number of turns, and the insulating member 28 is arranged between each of them.

[0041] According to the manufacturing method including the above-mentioned first step and second step, the electric motor 10 ( Figure 1 ).

[0042] Here, one of the viewpoints disclosed in this embodiment is described. In the type of motor 10 in which the slot 18 of the stator 16 is provided with a coil, it is assumed that when the inductance L of each of the plurality of wires 26 constituting the coil portion 20 is deviated, the current flowing through the coil portion 20 is unstable. In addition, as a result, it is difficult to obtain a stable output from the motor 10. The following is a specific example for explanation.

[0043] Figure 5A 2 is a diagram for explaining a conventional coil unit 20' in which the inductance L is unstable. Figure 5A In the figure, the elements shown upward are located closer to the inner side (toward the shaft 12 ) in the longitudinal direction of the wire 26 , and the elements shown downward are located closer to the front side (toward the outer peripheral side).

[0044] exist Figure 5A Schematically shows one of the plurality of winding groups 24' of the conventional coil unit 20' to which this embodiment is not applied. Figure 5A In FIG. 2 , the wire 26 a ′ and the wire 26 b ′ are two of the n wires 26 constituting the coil portion 20 ′.

[0045] The wire 26a' has a winding portion 30a' belonging to the winding group 24'. Similarly, the wire 26b' has a winding portion 30b' belonging to the winding group 24'. In the length direction of the wire 26, the position of the winding portion 30a' in the length direction of the wire 26 is closer to the front than the winding portion 30b'. In this way, as for the position of the winding portion 30a' in the wire 26a' and the position of the winding portion 30b' in the wire 26b', even if the winding portion 30a' and the winding portion 30b' belong to the same winding group 24', deviations may occur within the range of the winding length of the winding group 24'. The longer the winding length of the winding group 24', that is, the more the number of winding groups 24' is reduced and the more the number of turns of one winding group 24' is increased, the more likely the inconsistency of the position is to occur.

[0046] If the position of the winding portion 30a' and the position of the winding portion 30b' in the length direction of the wire 26 are inconsistent, the leakage magnetic flux Φl ( Figure 5A ), the magnitudes of the magnetic flux Φa' generated in the winding portion 30a' and the magnetic flux Φb' generated in the winding portion 30b' are inconsistent. Figure 5A Taking the example of , the magnitude of the magnetic flux Φb' is smaller than the magnetic flux Φa' by the amount of the leakage magnetic flux Φl (Φb'=Φa'-Φl).

[0047] As a result, the inductance La' of the winding portion 30a' determined based on the size of the magnetic flux Φa' and the inductance Lb' generated in the winding portion 30b' determined based on the size of the magnetic flux Φb' are inconsistent. This inconsistency is the deviation of the above-mentioned inductance L (La', Lb'). In addition, the leakage magnetic flux Φl is larger as it is closer to the axis 12. Therefore, the more the inconsistency between the positions of the winding portion 30a' and the winding portion 30b' in the longitudinal direction of the wire 26 occurs at a position close to the axis 12, the greater the deviation of the above-mentioned inductance L.

[0048] Figure 5B 2 is a diagram for explaining the coil unit 20 of the present embodiment. Figure 5B In the figure, the elements shown upward are located closer to the inner side (toward the shaft 12 ) in the longitudinal direction of the wire 26 , and the elements shown downward are located closer to the front side (toward the outer peripheral side).

[0049] exist Figure 5B Schematically shows one of the plurality of winding groups 24 included in the coil unit 20 of the present embodiment. Figure 5B In FIG. 2 , the wire 26 a and the wire 26 b are two of the n wires 26 constituting the coil portion 20 .

[0050] In the present embodiment, the windings 24 are sequentially arranged in the slots 18 in descending order of the number of turns along the direction toward the axis 12. Therefore, the number of turns of the windings 24 with a larger leakage flux Φ1 is suppressed, and as a result, the misalignment between the windings 30a and 30b in the length direction of the wire 26 is reduced, or the misalignment is easily adjusted in the manufacturing stage (winding formation step).

[0051] Since the misalignment between the winding portion 30a and the winding portion 30b is reduced, the deviation caused by the leakage magnetic flux Φl between the magnetic flux Φa generated in the winding portion 30a and the magnetic flux Φb generated in the winding portion 30b is also reduced, and the deviation between the inductance La of the winding portion 30a and the inductance Lb generated in the winding portion 30b is reduced.

[0052] That is, according to the present embodiment, it is possible to provide the electric motor 10 and the method for manufacturing the electric motor 10 which can reduce the variation in the inductance L of the coil portion 20 caused by the leakage magnetic flux Φ1.

[0053] In addition, in the present embodiment, the number of turns of the first winding group 24A, which is farther from the axis 12, is larger among the first winding group 24A, the second winding group 24B, and the third winding group 24C which are sequentially arranged in the direction toward the axis 12. Thus, the variation of the inductance L can be reduced for the winding group 24 close to the axis 12 where the influence of the leakage magnetic flux Φ1 is more likely to be apparent, and the number of steps for manufacturing the motor 10 can be suppressed from being excessively increased.

[0054] [Modifications]

[0055] The above embodiment is described as an example of the present invention, and of course, various changes or improvements can be added to the above embodiment. According to the description of the claims, the various changes or improvements are also included in the technical scope of the present invention.

[0056] (Variant 1)

[0057] In the embodiment, a mechanism has been described in which, for each of all the slots 18 formed in the stator 16 , the plurality of winding groups 24 are sequentially provided in the slots 18 in descending order of the number of turns along the direction toward the shaft 12 .

[0058] The present invention is not limited thereto, and with respect to at least one of the plurality of slots 18 formed in the stator 16 , the plurality of winding groups 24 may be sequentially disposed in the slot 18 in descending order of the number of turns along the direction toward the shaft 12 .

[0059] Thus, for the at least one slot 18 , the variation in the inductance L of the coil portion 20 caused by the leakage magnetic flux Φ1 can be reduced.

[0060] (Variant 2)

[0061] The insulating member 28 may also be omitted from the structure of the electric motor 10. Likewise, the insulating member inserting step may also be omitted from the method of manufacturing the electric motor 10.

[0062] [Inventions according to embodiments]

[0063] Hereinafter, inventions that can be grasped from the above-described embodiment and modified examples will be described.

[0064] <First Invention>

[0065] A motor 10 comprises: a shaft 12; and a stator 16, which is arranged on the outer periphery of the above-mentioned shaft 12 and is formed with a plurality of slots 18 extending toward the above-mentioned shaft 12, and a coil portion 20 composed of a plurality of wires 26 connected in parallel is provided relative to each of the plurality of the above-mentioned slots 18, wherein the above-mentioned coil portion 20 provided in at least one of the plurality of the above-mentioned slots 18 formed in the above-mentioned stator 16 has a plurality of winding groups 24 connected in series and having different numbers of turns, and the plurality of the above-mentioned winding groups 24 are arranged in the above-mentioned slots 18 in the order of the number of turns from large to small along the direction toward the above-mentioned shaft 12.

[0066] Thus, it is possible to provide the electric motor 10 which can reduce the variation in the inductance L of the coil portion 20 caused by the leakage magnetic flux Φ1.

[0067] Alternatively, the coil portion 20 provided in each of all the slots 18 formed in the stator 16 may include a plurality of winding groups 24 connected in series and having different numbers of turns, and the plurality of winding groups 24 may be provided in the slots 18 in a decreasing order of the number of turns along the direction toward the shaft 12. Thus, the motor 10 can be provided in which the deviation of the inductance L of the coil portion 20 caused by the leakage magnetic flux Φ1 is further reduced.

[0068] An insulating member 28 may be further provided between the plurality of winding groups 24 adjacent to each other in the direction toward the axis 12. Thus, it is possible to prevent accidental electrical interference between the plurality of winding groups 24 in the slot 18.

[0069] <Second invention>

[0070] A method for manufacturing an electric motor 10, the electric motor 10 comprising: a shaft 12; and a stator 16, which is arranged on the outer periphery of the shaft 12 and has a plurality of slots 18 extending toward the shaft 12, the method for manufacturing the electric motor 10 comprising: a first step of forming a coil portion 20 composed of a plurality of wires 26 connected in parallel into a plurality of winding groups 24 connected in series and having different numbers of turns; and a second step of arranging the plurality of winding groups 24 in at least one of the plurality of slots 18 formed in the stator 16 in an order of the number of turns from large to small along a direction toward the shaft 12.

[0071] Thus, it is possible to provide a method for manufacturing the electric motor 10 in which the variation in the inductance L of the coil portion 20 caused by the leakage magnetic flux Φ1 is reduced.

[0072] Alternatively, in the second step, the plurality of winding groups 24 may be arranged in each of all the slots 18 formed in the stator 16 in the order of the number of turns from large to small along the direction toward the shaft 12. Thus, a method for manufacturing the motor 10 that further reduces the deviation of the inductance L of the coil portion 20 caused by the leakage magnetic flux Φ1 can be provided.

[0073] The second step may include providing an insulating member 28 between the plurality of winding groups 24 adjacent to each other in the direction toward the axis 12. This can prevent the plurality of winding groups 24 from interfering with each other in the slot 18.

Claims

1. An electric motor comprising: a shaft; and a stator, which is provided on the outer periphery of the shaft and has a plurality of slots extending toward the shaft, and a coil portion consisting of a bundle of a plurality of wires bundled is provided for each of the plurality of slots, The electric motor is characterized in that The coil portion provided in at least one of the plurality of slots formed in the stator has a plurality of winding groups connected in series and having different numbers of turns, and the plurality of winding groups are provided in the slot in a decreasing order of the number of turns along a direction toward the axis, The plurality of wires each have a plurality of winding portions belonging to different winding groups along the length direction of the wire harness. In each of the plurality of winding groups, the winding portions of the wires different from each other are connected in parallel. Among the plurality of winding groups, at least the first winding group, which is the winding group located closest to the axis, has the smallest displacement in the longitudinal direction between the plurality of winding portions compared to the displacement in the winding groups other than the first winding group.

2. The electric motor according to claim 1, characterized in that An insulating member is further provided, the insulating member being provided between the plurality of winding groups adjacent to each other in the direction toward the axis.

3. A method for manufacturing an electric motor, the electric motor comprising: a shaft; and a stator, which is provided on the outer periphery of the shaft and has a plurality of slots extending toward the shaft, The method for manufacturing the electric motor is characterized by comprising: In a first step, a coil portion composed of a bundle of a plurality of wires bundled together is formed into a plurality of winding groups connected in series and having different numbers of turns; as well as In a second step, the plurality of winding groups are arranged in at least one of the plurality of slots formed in the stator in a decreasing order of the number of turns along a direction toward the axis. The plurality of wires each have a plurality of winding portions belonging to different winding groups along the length direction of the wire harness. In each of the plurality of winding groups, the winding portions of the wires different from each other are connected in parallel. Among the plurality of winding groups, at least the first winding group, which is the winding group located closest to the axis, has the smallest displacement in the longitudinal direction between the plurality of winding portions compared to the displacement in the winding groups other than the first winding group.

4. The method for manufacturing an electric motor according to claim 3, characterized in that: The second step includes the step of providing an insulating member between the plurality of winding groups adjacent to each other in the direction toward the axis.

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