CN108886304B

CN108886304B - Stator for electric motor and method for manufacturing the same, electric motor and method for manufacturing the same

Info

Publication number: CN108886304B
Application number: CN201780020910.8A
Authority: CN
Inventors: 村上俊辅; 芳贺英博; 上田智哉; 小川幸祐
Original assignee: Nidec Corp
Current assignee: Nidec Corp
Priority date: 2016-03-31
Filing date: 2017-03-25
Publication date: 2021-02-05
Anticipated expiration: 2037-03-25
Also published as: WO2017170298A1; CN108886304A

Abstract

The method for manufacturing the stator (200) comprises the following steps: a step of preparing a plurality of annular core pieces (230), at least one of which has at least one connecting portion (233) that connects the tips of two adjacent teeth; cutting the connecting part; a step of laminating a plurality of annular core pieces to obtain a laminated annular core (210) having M laminated teeth; a step of dividing the laminated annular core into a plurality of divided cores (250) of M or less each including at least one laminated tooth; a step of mounting a winding (220) on at least one of the plurality of divided cores; and a step of reassembling the plurality of divided cores after the winding wire is attached to produce an annular stator, wherein cut surfaces of the cut connecting portions are brought into contact with each other at the time of reassembling.

Description

Stator for electric motor and method for manufacturing the same, electric motor and method for manufacturing the same

Technical Field

The present invention relates to a method for manufacturing an electric motor stator, a method for manufacturing an electric motor, an electric motor stator, and an electric motor.

Background

In recent years, there has been an increasing demand for electric motors (hereinafter simply referred to as "motors") to reduce vibrations. In particular, a motor for an electric power steering apparatus is further required to have a low vibration in order to improve a steering feeling. As this method, for example, a technique is known in which the rigidity of the stator is increased to reduce the vibration of the motor.

For example, patent document 1 discloses an annular stator including a tooth core in which a plurality of core members are stacked, and an annular yoke core fitted to an outer peripheral portion of the tooth core. Each of the core elements has a plurality of teeth and a bridge portion connecting the tips of two adjacent teeth of the plurality of teeth to each other. As a method of manufacturing a stator, a steel plate is punched to form a plurality of core members. A toothed core is obtained by laminating a plurality of core elements so that each core element rotates by a constant angle. The winding wire is fitted from the outer peripheral side of the tooth core and then the tooth core is press-fitted into the inner peripheral portion of the yoke core to obtain a stator. According to this stator configuration, the mechanical strength of the stator is improved by the bridge portion, and the leakage of magnetic flux is reduced. Further, according to this manufacturing method, the work of attaching the winding wire and the work of inserting the tooth core are facilitated.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 3-169235

Disclosure of Invention

Problems to be solved by the invention

Further improvements in ease of assembly of the stator of the motor and leakage of magnetic flux are desired.

Embodiments of the present invention provide a method of manufacturing a stator that can easily assemble the stator, and a stator that can further reduce leakage flux.

Means for solving the problems

An exemplary method of manufacturing a motor stator according to the present invention includes the steps of: a step (a) of preparing a plurality of annular core pieces each having an annular core back and M (M is an integer of 2 or more) teeth arranged at substantially equal intervals on an inner periphery of the core back and protruding toward a center of the core back, at least one of the plurality of annular core pieces having at least one connecting portion connecting tip ends of two adjacent teeth to each other; a step (B) of cutting the connecting portion; a step (C) of laminating a plurality of the ring-shaped core pieces to obtain a laminated ring-shaped core having M laminated teeth; a step (D) of dividing the laminated annular core into a plurality of M or less divided cores each including at least one laminated tooth; a step (E) of mounting a winding wire to at least one of the plurality of divided cores; and (F) producing an annular stator by reassembling the plurality of split cores after the winding wire is attached, and bringing the cut surfaces of the connecting portions cut in the step (B) into contact with each other at the time of reassembling.

An exemplary stator of the present invention includes: a laminated body including a plurality of laminated teeth laminated by a plurality of annular core pieces, each of the plurality of laminated teeth including an annular core back and M teeth, the teeth being arranged at substantially equal intervals on an inner periphery of the core back and protruding toward a center of the core back; and a winding wire attached to at least one of the M laminated teeth, wherein at least one of the plurality of annular core pieces of the laminated body has at least one connecting portion that connects the tips of two adjacent teeth and includes a seam.

Effects of the invention

According to the embodiments of the present invention, there are provided a manufacturing method of a stator capable of easily assembling the stator and a stator capable of further reducing leakage flux.

Drawings

Fig. 1 is a sectional view along a central axis 500 showing an exemplified configuration of the motor 100.

Fig. 2 is a perspective view of the laminate 210.

Fig. 3 is a plan view of stator 200 in a state where winding 220 is attached to laminated body 210, as viewed from the laminating direction of laminated body 210.

Fig. 4 is a plan view of the annular core segment 230 constituting the stacked body 210, as viewed from the stacking direction of the stacked body 210.

Fig. 5A is an enlarged schematic view showing a pair of adjacent two laminated teeth 212.

Fig. 5B is an enlarged schematic view showing one of the plurality of coupling portions 233 located between a pair of adjacent two laminated teeth 212.

Fig. 6 is a development view of the laminated body 210 obtained by cutting the laminated core back 211 positioned between a certain pair of the laminated teeth 212 in the y direction and developing the laminated body 210 in the x direction.

Fig. 7 is a flowchart illustrating a flow of a manufacturing method of the motor 100 and the stator 200.

Fig. 8A is a schematic diagram showing a case where electromagnetic steel sheet 700 is punched out in a ring shape using die 800 to mold a plurality of ring-shaped core pieces 230.

Fig. 8B is a schematic view showing a plurality of ring-shaped core pieces 230 formed by blanking.

Fig. 9 is a schematic view showing a state where the coupling portion 233 is cut by the cutting blade 710.

Fig. 10 is a schematic view showing a case where a plurality of ring-shaped core pieces 230 are stacked so as to rotate in the circumferential direction by a predetermined angle for each ring-shaped core piece 230.

Fig. 11A is a schematic diagram showing a case where the laminated annular core 210 is divided into twelve divided cores 250.

Fig. 11B is a schematic diagram illustrating a state where the jig 900 is inserted into the slot 214 to divide the laminated annular core 210.

Fig. 11C is a plan view of twelve divided cores 250 viewed from the stacking direction of the stacked annular cores 210.

Fig. 12A is a plan view of the divided core 250 to which the winding 220 is attached.

Fig. 12B is a perspective view of the divided core 250 in which the winding 220 is attached to the laminated teeth 212.

Fig. 13 is a schematic view of the laminated ring core 210 divided into a plurality of divided cores 250 being restored to a ring shape by using a jig.

Fig. 14 is a schematic view showing a state where the cut surfaces of the coupling portion 233 are brought into contact with each other at the time of reassembly.

Detailed Description

Before the embodiments of the present invention are explained, the recognition of the present inventors that is the basis of the present invention will be explained.

According to the method of manufacturing a stator disclosed in patent document 1, the tooth cores and the yoke core are prepared as separate members in order to wind the winding wire around the respective teeth of the tooth cores. Therefore, after the winding wire is attached to each tooth from the outer peripheral side of the tooth core, the tooth core needs to be press-fitted into the inner peripheral portion of the yoke core. However, according to this assembly method, before the tooth cores are press-fitted into the inner peripheral portion of the yoke core, the plurality of teeth are connected to each other only by the bridge portions of the core members formed of one steel plate. Therefore, the bridge portion may be easily deformed by an external force. If the bridge portion is deformed, there is a possibility that the tooth core cannot be press-fitted into the yoke core. Further, there is a possibility that contamination may occur at the time of press-fitting.

According to the stator disclosed in patent document 1, each core member has the bridge portion only between a pair of adjacent two of the plurality of teeth, and therefore, leakage of magnetic flux is reduced, and as a result, torque ripple at startup is improved. However, since a pair of adjacent two teeth are still connected to each other by the bridge portion, it is considered that a leakage flux occurs through the bridge portion.

Hereinafter, embodiments of a method for manufacturing a stator for a motor, a method for manufacturing a motor, a stator for a motor, and a motor according to the present invention will be described in detail with reference to the drawings. However, an excessive detailed description may be omitted. For example, detailed descriptions of already known matters and repetitive descriptions of substantially the same structures may be omitted. This is to avoid unnecessarily obscuring the following description, as will be readily understood by those skilled in the art.

(embodiment mode)

The motor 100 of the present embodiment is a so-called inner rotor type motor. The motor 100 is mounted on, for example, an automobile, and is preferably used as a motor for an electric power steering apparatus. In this case, the motor 100 generates a driving force of the electric power steering apparatus.

The motor 100 includes a stator 200, a rotor 300, a housing 400, a cover 420, a lower bearing 430, and an upper bearing 440. In addition, the stator 200 is also referred to as an armature.

The housing 400 is a substantially cylindrical case having a bottom, and houses the stator 200, the lower bearing 430, and the rotor 300 therein. A recess 410 holding the lower bearing 430 is located at the center of the bottom of the housing 400. The lid 420 is a plate-like member that covers an opening in the upper portion of the housing 400. A circular hole 421 that holds the upper bearing 440 is located at the center of the cover 420.

The stator 200 is annular and includes a laminated body (sometimes referred to as a "laminated annular core") 210 and a winding (sometimes referred to as a "coil") 220. The stator 200 generates magnetic flux according to the driving current. The laminated body 210 is formed of laminated steel plates obtained by laminating a plurality of steel plates in a direction along the central axis 500 (y direction in fig. 1), and includes an annular laminated core back 211 and a plurality of laminated teeth (teeth) 212. The laminated core back 211 is fixed to the inner wall of the case 400. The structure of the stator 200 will be described in detail later. In addition, the central axis 500 is the rotation axis of the rotor 300.

The winding 220 is made of a conductive wire (generally, a copper wire), and is typically attached to each of the plurality of laminated teeth 212 of the laminated body 210.

The lower bearing 430 and the upper bearing 440 are mechanisms that support the shaft 340 of the rotor 300 to be rotatable. For example, as the lower bearing 430 and the upper bearing 440, a ball bearing in which an outer ring and an inner ring are relatively rotated via a ball can be used. A ball bearing is shown in fig. 1.

The outer race 431 of the lower bearing 430 is fixed to the recess 410 of the housing 400. The outer race 441 of the upper bearing 440 is fixed to the rim of the circular hole 421 of the cover 420. The

inner races

432, 442 of the lower bearing 430 and the upper bearing 440, respectively, are fixed to the shaft 340. Therefore, the shaft 340 is supported to be rotatable with respect to the housing 400 and the cover 420.

The rotor 300 has

rotor units

310, 320, a shaft 340, and a cover 350. The shaft 340 is a substantially cylindrical member extending in the vertical direction along the center axis 500. The shaft 340 is rotatably supported by the lower bearing 430 and the upper bearing 440 and can rotate about the central axis 500. The shaft 340 has a head 341 at the tip on the cover 420 side. The head 341 is connected to a power transmission mechanism such as a gear for transmitting a driving force to an electric power steering apparatus of an automobile, for example.

The

rotor units

310 and 320 and the cover 350 rotate together with the shaft 340 in the radial inner space of the stator 200. The

rotor units

310 and 320 each have a rotor core 331, a magnet holder 332, and a plurality of magnets 333. The

rotor units

310 and 320 are arranged along the central axis 500 in a state of being inverted vertically with respect to each other.

The cover 350 is a substantially cylindrical member that holds the

rotor units

310 and 320. The cover 350 covers the outer circumferential surfaces and a part of the upper and lower end surfaces of the

rotor units

310 and 320. Thereby, the

rotor units

310, 320 are held in a state of being close to or in contact with each other.

In the motor 100, when a drive current flows through the winding 220 of the stator 200, a magnetic flux in the radial direction is generated in the plurality of laminated teeth 212 of the laminated body 210. A torque is generated in the circumferential direction by the action of the magnetic flux between the plurality of laminated teeth 212 and the magnet 333, and the rotor 300 is rotated about the central axis 500 with respect to the stator 200. When the rotor 300 rotates, a driving force is generated in, for example, an electric power steering apparatus.

Next, the structure of the stator 200 of the present embodiment will be described in detail with reference to fig. 2 to 6.

The stator 200 according to the embodiment of the present invention may have M (M is an integer of 2 or more) teeth (in other words, M slots). Hereinafter, a structure of the stator 200 having twelve teeth (twelve slots) will be described as a specific example.

Fig. 2 is a perspective view of the laminate 210. Fig. 3 is a plan view of stator 200 in a state where winding 220 is attached to laminated body 210, as viewed from the laminating direction of laminated body 210. Fig. 4 is a plan view of the annular core segment 230 constituting the stacked body 210, as viewed from the stacking direction of the stacked body 210.

Stator 200 includes laminated body 210 and winding 220. The laminated body 210 has twelve laminated teeth 212 and a laminated core back 211. The twelve laminated teeth 212 protrude toward the center of the annular laminated core back 211. There is a slot 214 between two adjacent stacked teeth 212.

A winding 220 is attached to each laminated tooth 212. However, the coil 220 may be mounted to at least one of the twelve laminated teeth 212. For example, the winding wire may be attached to nine or six of the twelve laminated teeth 212.

In the laminated body 210, a plurality of ring-shaped core pieces 230 are laminated. The laminated body 210 of the present embodiment includes sixty annular core pieces 230. However, the number of stacked layers is not limited to this, and is determined appropriately according to the required characteristics required for the motor, for example. For example, the number of stacked layers may be the same as the number of slits, or may be larger than the number of slits. Of course, the number of stacked layers may be smaller than the number of slits.

The ring core piece 230 has: an annular core back 231; and twelve teeth 232 arranged at substantially equal intervals on the inner periphery of the core back 231 and protruding toward the center of the core back 231. The front ends of the twelve teeth 232 are arranged in a ring shape, forming the inner circumference of the ring-shaped core piece 230. The plurality of annular core pieces 230 are stacked in the stacked body 210 such that the positions of the twelve teeth 232 are aligned between the plurality of annular core pieces 230. As shown in fig. 4, the ring-shaped core piece 230 has one coupling portion 233 that couples the leading ends of a pair of two adjacent teeth 232 to each other and includes a seam. However, the present invention is not limited to this, and each ring-shaped core piece 230 may have a plurality of coupling portions 233. Further, for example, two consecutive ring-shaped core pieces 230, one ring-shaped core piece 230 having twelve coupling portions 233 as many as the teeth 232 and the other ring-shaped core piece 230 not having the coupling portions 233, may be repeatedly laminated in the laminated body 210. In the present invention, at least one ring-shaped core piece 230 of the plurality of ring-shaped core pieces 230 may have at least one coupling portion 233. In other words, the laminated body 210 may have at least one coupling portion 233.

Fig. 5A shows a pair of adjacent two laminated teeth 212 in an enlarged scale. Fig. 5B shows one of the plurality of coupling portions 233 between a pair of adjacent two laminated teeth 212 in an enlarged manner. Fig. 6 is a development view of the laminated body 210 obtained by cutting the laminated core back 211 positioned between a certain pair of the laminated teeth 212 in the y direction and developing the laminated body 210 in the x direction.

A plurality of coupling portions 233 exist between the leading ends of a pair of adjacent two laminated teeth 212. In the present embodiment, the coupling portions 233 are present between sixty ring-shaped core pieces 230 every twelve ring-shaped core pieces 230. Five coupling portions 233 exist between the front ends of a pair of adjacent two laminated teeth 212. This is merely an example, and the coupling portion 233 may be arranged in various patterns. For example, five coupling portions 233 may be present between the distal ends of a certain pair of adjacent two laminated teeth 212, and four coupling portions 233 may be present between the distal ends of another pair of adjacent two laminated teeth 212. Further, five or more coupling portions 233 may be present between the distal ends of a certain pair of adjacent two laminated teeth 212, and no coupling portion 233 may be present between the distal ends of another pair of adjacent two laminated teeth 212. According to the present invention, the laminated body 210 may have at least one connecting portion 233. For example, the same number of coupling portions 233 as the teeth 232 may be present in one ring-shaped core piece 230, and the coupling portions 233 may not be present at all in one ring-shaped core piece.

As shown in fig. 5B, the coupling portion 233 has a seam 234. The seam 234 appears to be contiguous in appearance. However, as shown in fig. 9, which will be described later in detail, the seam 234 includes two cut

surfaces

235A and 235B which are obtained by mechanical cutting. Specifically, the first cut surface 235A on one side of two adjacent teeth 212 of the coupling portion 233 and the second cut surface 235B on the other side of the coupling portion 233 are in contact with each other at the joint 234. Further, an adhesive or the like may be interposed between the two

cut surfaces

235A and 235B, or the two

cut surfaces

235A and 235B may be coated with a nonmagnetic material.

As described above, according to the structure of the stator of patent document 1, a pair of adjacent two teeth portions are still connected to each other by the continuous bridge portion that is not mechanically cut, and therefore, a magnetic flux leakage occurs through the bridge portion. On the other hand, although the coupling portion 233 of the present invention is mechanically cut and discontinuous, the cut surfaces of the coupling portion 233 contact each other. Therefore, when a force to reduce the distance between two adjacent teeth 232 is applied to the stator 200 due to a magnetic force generated in the radial direction of the stator 200 during the rotation of the motor, the coupling portion 233 can suppress the force. In this way, the rigidity of the stator (specifically, the strength of the inner peripheral portion of the stacked body 210) can be improved by the coupling portion 233. Further, the cross section obtained by mechanical cutting can suppress leakage of magnetic flux passing through the connection portion 233. Suppression of the magnetic flux leakage is related to improvement of cogging torque, for example.

The laminated body 210 may have a plurality of coupling portions 233 arranged periodically in the circumferential direction of the core back 231 (in other words, a ring formed at the distal ends of the plurality of teeth 232) between the plurality of annular core pieces 230. As shown in fig. 6, focusing on twelve continuous ring-shaped core pieces 230 out of sixty ring-shaped core pieces 230 in the stacked body 210, twelve connecting portions 233 can be arranged so as to be present in two adjacent slits 214 between adjacent ring-shaped core pieces 230. In other words, the twelve coupling portions 233 may be spirally present in the circumferential direction between the plurality of annular core pieces 230. By adopting the spiral structure, the coupling portion 233 can secure the strength of at least the inner peripheral portion of the stacked body 210.

A specific example of the method of manufacturing the motor 100 and the stator 200 will be described with reference to fig. 7 to 14.

Fig. 7 shows an exemplary flow of a method of manufacturing the motor 100 and the stator 200. The method for manufacturing the stator 200 according to the present embodiment includes the step of preparing the plurality of ring-shaped core pieces 230 (S600), the step of cutting the connection portion 233 (S610), the step of obtaining the laminated ring-shaped core (laminated body) 210 (S620), the step of dividing the laminated ring-shaped core 210 into the plurality of divided cores 250 (S630), the step of attaching the winding 220 to the divided cores 250 (S640), and the step of obtaining the stator 200 by assembling the plurality of divided cores 250 again (S650). The method of manufacturing the motor 100 includes a step of housing the stator 200 and the rotor 300 in the case 400 (S660) in addition to these steps.

First, in step S600, a plurality of ring-shaped core pieces 230 shown in fig. 4 are prepared. For example, twelve or more ring-shaped core pieces 230 are prepared, the number of which is the same as that of the teeth 232. As described above, the number of prepared units is not limited to this, and is determined appropriately according to the required characteristics required of the motor 100, for example. To obtain the laminated body 210 shown in fig. 2, for example, sixty ring-shaped core pieces 230 are prepared. Each ring-shaped core piece 230 includes a core back 231, twelve teeth 232, and a coupling portion 233 that couples the tips of a pair of adjacent teeth 232 to each other. In step 600, joint 233 has not yet joined seam 234. In addition, at least one of the plurality of annular core pieces 230 may have at least one connection portion 233, and a required number of annular core pieces 230 may be prepared.

Fig. 8A schematically shows a case where a plurality of annular core pieces 230 are formed by punching an electromagnetic steel sheet 700 into an annular shape using a die 800. Fig. 8B schematically shows a plurality of ring-shaped core pieces 230 formed by blanking. As a method for preparing a plurality of annular core segments 230, as shown in the figure, a plurality of annular core segments 230 can be formed by placing an electromagnetic steel sheet 700 on a die 810 and punching the electromagnetic steel sheet 700 into an annular shape using a die (punch) 800. In addition to press working, wire electric discharge machining or laser machining, for example, can also be used. Alternatively, for example, a plurality of ring-shaped core pieces 230 may be supplied from a supplier as components. In the present embodiment, sixty annular core pieces 230 are formed by punching the electrical steel sheet 700 into an annular shape using a die 800.

Next, in step S610, the coupling portion 233 is cut.

Fig. 9 schematically shows a case where the coupling portion 233 is cut by the cutting blade 710. For example, the joint 234 is formed by mechanically cutting the coupling portion 233 at substantially the center thereof with the cutting blade 710. Thus, a first cut surface 235A is formed on one side of two adjacent teeth 232 of the coupling portion 233, and a second cut surface 235B is formed on the other side of the coupling portion 233. The coupling portions 233 are mechanically cut for each of the ring-shaped core pieces 230, and the joint 234 is formed in all the coupling portions 233 included in the plurality of ring-shaped core pieces 230. Since the laminated ring core 210 is divided in step S630 described later, it is preferable to leave the notch 237 at substantially the center of the core back 231 between the two adjacent teeth 232 as shown in fig. 9.

Next, in step S620, the plurality of ring-shaped core pieces 230 are stacked to obtain the stacked ring-shaped core 210 having twelve stacked teeth 212. In the present embodiment, after sixty ring-shaped core pieces 230 are stacked, the plurality of ring-shaped core pieces 230 are fixed to each other by, for example, pressure bonding, adhesion, or laser welding. Thus, a laminated annular core 210 having twelve laminated teeth 212 is obtained. The laminated annular core 210 corresponds to the laminated body 210 described above.

Fig. 10 schematically shows a case where a plurality of ring-shaped core pieces 230 are stacked so as to be rotated in the circumferential direction by a predetermined angle. Fig. 10 shows two ring-shaped core pieces 230 out of sixty ring-shaped core pieces 230. The plurality of annular core pieces 230 are preferably stacked so as to be rotated in the circumferential direction by a predetermined angle. Such a stack is generally referred to as a "spin stack". By the rotational lamination, the coupling portion 233 is arranged in a spiral shape, and therefore, the strength of the inner peripheral portion of the laminated annular core 210 can be ensured.

The predetermined angle is N times (360/M) (N is an integer of 1 or more). As described above, M represents the number of teeth (or notches). When M is 12, the predetermined angle is an integral multiple of 30 °. In the present embodiment, as shown in fig. 10, sixty ring-shaped core pieces are stacked so as to rotate clockwise by 30 ° for each 1 core piece. As a result, the laminated annular core 210 has an arrangement pattern (i.e., a spiral structure) of the coupling portions 233 as shown in fig. 6. The y direction shown in fig. 10 is a direction parallel to the central axis of the laminated annular core 210. Sixty ring-shaped core pieces 230 are stacked in the y direction with twelve teeth 232 aligned.

Next, in step S630, the laminated annular core 210 is divided into twelve or less divided cores 250.

Fig. 11A schematically shows a case where the laminated annular core 210 is divided into twelve divided cores 250. Fig. 11B schematically shows a case where the jig 900 is inserted into the slot 214 to divide the laminated annular core 210. Fig. 11C is a plan view of twelve divided cores 250 viewed from the stacking direction of the stacked annular cores 210. Fig. 11B shows a part of the laminated toroidal core 210 in an enlarged manner. The jig 900 is inserted into the notch 214 in the direction of an arrow, for example, as shown in fig. 11A. Specifically, as shown in fig. 11B, the jig 900 is inserted into the slot 214, and a force is applied in the circumferential direction of the laminated annular core 210, thereby dividing the laminated annular core 210 into twelve divided cores 250 each having one laminated tooth 212. In step S610, the cutouts 237 are formed in advance in the core back 231 of each ring-shaped core piece 230, and thus the division of the laminated ring-shaped core 210 is facilitated. The jig 900 may be inserted into each of the plurality of slits 214 to be divided, or the jig 900 may be inserted into a plurality of slits 214 at the same time to be divided.

In the case of concentrated winding, the laminated annular core 210 is divided so that each of the divided cores 250 has one laminated tooth 212 in principle.

Next, in step S640, the winding 220 is attached to at least one of the twelve divided cores 250.

Fig. 12A is a plan view of the divided core 250 to which the winding 220 is attached. Fig. 12B is a perspective view of the divided core 250 in which the winding 220 is attached to the laminated teeth 212. In the present embodiment, the insulating member 260 is attached to each of the laminated teeth 212 of the twelve divided cores 250, and then the winding 220 is attached to the insulating member 260 (so-called concentrated winding). As a method of winding the wire around the division core 250, for example, spindle winding and nozzle winding can be used. It is not necessary to attach the winding 220 to all the divided cores 250 (stacked teeth 212), and the winding 220 may be attached to a required number of the divided cores 250 according to design specifications or the like. In other words, the winding 220 may be attached to at least one of the laminated teeth 212 of the twelve divided cores 250. For example, the winding 220 may be attached to nine laminated teeth 212 of the twelve divided cores 250.

Next, in step S650, the plurality of divided cores 250 each having the winding 220 mounted thereon are reassembled to obtain the ring-shaped stator 200.

Fig. 13 schematically shows a case where the laminated annular core 210 divided into the plurality of divided cores 250 is restored to an annular shape by using a jig (not shown). Fig. 14 schematically shows a state where the cut surfaces of the coupling portion 233 are brought into contact with each other at the time of reassembly. The "reassembly" refers to fixing the plurality of divided cores 250 to each other and restoring the shape before division (i.e., a ring shape). Specifically, after the winding 220 is attached, the twelve divided cores 250 are assembled again, thereby producing the ring-shaped stator 200. When the connection portions 233 are reassembled, the cut surfaces of the connection portions 233 cut in step S610 are brought into contact with each other. In the present embodiment, twelve divided cores 250 are reassembled using a jig. At this time, as shown in fig. 14, the cut surfaces (first and second cut surfaces 235A and 235B) of the sixty mechanically cut coupling portions 233 are brought into contact with each other. The plurality of division cores 250 are fixed by, for example, bonding or laser welding. This fixation is performed in consideration of (1) circumferential unevenness between the plurality of laminated teeth 212 and (2) axial height unevenness of the laminated annular core 210. Further, after the connecting portion 233 is cut and before the cut surfaces are brought into contact with each other, each cut surface may be coated with a nonmagnetic material. Further, the cut surfaces may be brought into contact with each other with an adhesive interposed therebetween.

As in patent document 1, a tooth core (corresponding to a member obtained by removing a core back 231 from an annular core piece 230) and a yoke core (corresponding to the core back 231) are prepared as separate members. In this case, for example, since blanking unevenness (error) may occur between the plurality of teeth 232 due to the die, positional displacement of the tips of the teeth 232 occurs at the time of assembly (particularly, after the tooth core is pressed into the yoke core), and it is difficult to bring the tips of two adjacent teeth into contact with each other. On the other hand, according to the present embodiment, the annular core piece 230 including the core back 231 and the coupling portion 233 is punched out into an annular shape, and then the coupling portion 233 is cut. Since the core back 231 and the plurality of teeth 232 are integrated, the cut surfaces can be maintained in contact with each other even after the connecting portion 233 is cut. In this state, since the plurality of laminated ring-shaped core pieces 230 are laminated, the cut surfaces can be maintained in contact with each other before (immediately before) the laminated ring-shaped core 210 is divided. Further, since the press-fitting operation is not performed, the position of the tip of the tooth 232 does not shift during the press-fitting operation. Therefore, when the divided cores 250 are assembled again, the cut surfaces of the cut coupling portions 233 can be brought into contact with each other.

In the method of manufacturing the motor 100, the stator 200 and the rotor 300 are housed in the case 400 in step S660.

An example of a method of manufacturing the rotor 300 will be briefly described. The rotor core 331 and the magnet holder 332 are integrated by insert molding. Specifically, resin is injected around rotor core 331 inserted into the mold to integrate rotor core 331 and the resin. The resin becomes the magnet holder 332 when it is cooled and solidified. Next, the magnet 333 is inserted into the integrated rotor core 331 and magnet holder 332. Thus, the magnet 333 is fixed to the side surface of the rotor core 331 while being supported by the magnet holder 332.

A lower bearing 430 (e.g., a ball bearing) is disposed in the recess 410 of the housing 400. Next, the stator 200 is housed in the case 400, the shaft 340 is inserted into the lower bearing 430, and the rotor 300 integrated with the shaft 340 is disposed in the internal space of the stator 200. Finally, an upper bearing 440 (e.g., a ball bearing) is disposed in the circular hole 421 of the lid portion 420, and the opening in the upper portion of the housing 400 is covered by the lid portion 420.

A part of the above-described manufacturing process can be replaced with a known manufacturing method (for example, a method disclosed in patent document 1).

According to the method of manufacturing the motor 100 and the stator 200 of the present embodiment, the joint 234 is formed in the connecting portion 233, and the laminated annular core 210 is divided, whereby the winding 220 can be easily attached to the plurality of laminated teeth 212 without being affected by the connecting portion 233, and the operation of pressing into the laminated core back 211 as in patent document 1, for example, is not required. As a result, not only the assembly of the stator 200 is easy, but also the disadvantage of contamination at the time of press-fitting can be prevented. In addition, since there is no state in which only the coupling portion 233 is coupled in the assembly process, the coupling portion 233 can be prevented from being deformed.

Industrial applicability

Embodiments of the present invention can be widely applied to various motors used in a vacuum cleaner, a dryer, a ceiling fan, a washing machine, a refrigerator, an electric power steering apparatus, and the like.

Description of the reference symbols

100: a motor; 200: a stator; 210: lamination (lamination of annular cores); 211: a laminated core back; 212: laminating the teeth; 214: grooving; 220: coiling; 230: an annular iron core plate; 231: the back of the iron core; 232: teeth; 233: a connecting portion; 234: seaming; 235A: a first cutting surface; 235B: a second cut surface; 237: cutting; 250: dividing the iron core; 260: an insulating member; 300: a rotor; 400: a housing.

Claims

1. A method for manufacturing a stator for an electric motor, the method comprising the steps of:

a step (a) of preparing a plurality of annular core pieces, each of the plurality of annular core pieces having an annular core back portion and M teeth, the teeth being arranged at substantially equal intervals on an inner circumference of the core back portion and protruding toward a center of the core back portion, and at least one of the plurality of annular core pieces having at least one connecting portion connecting tip ends of two adjacent teeth, wherein M is an integer of 2 or more;

a step (B) of cutting the connecting portion;

a step (C) of laminating a plurality of the ring-shaped core pieces to obtain a laminated ring-shaped core having M laminated teeth;

a step (D) of dividing the laminated annular core into a plurality of M or less divided cores each including at least one laminated tooth;

a step (E) of mounting a winding wire to at least one of the plurality of divided cores; and

and (F) reassembling the plurality of split cores after the winding wire is attached to produce an annular stator, and bringing the cut surfaces of the connecting portions cut in the step (B) into contact with each other when reassembling the annular stator.

2. The manufacturing method according to claim 1,

in the step (D), the laminated annular core is divided into M divided cores each including one laminated tooth,

in the step (E), a winding wire is attached to at least one laminated tooth of the M divided cores,

in the step (F), after the winding wire is attached, the M divided cores are assembled again by bringing the cut surfaces of the connecting portion into contact with each other, thereby producing the annular stator.

3. The manufacturing method according to claim 1 or 2,

in the step (a), the electromagnetic steel sheet is punched out into a ring shape to form a plurality of ring-shaped core pieces.

4. The manufacturing method according to claim 1 or 2,

the plurality of ring-shaped core pieces prepared in the step (a) each have at least one of the connecting portions that connects the tips of two adjacent teeth,

in the step (B), the connecting portion is cut for each annular core piece.

5. The manufacturing method according to claim 1 or 2,

in the step (C), the laminated annular core is obtained by laminating a plurality of the annular core pieces so that each of the annular core pieces rotates in the circumferential direction at a predetermined angle.

6. The manufacturing method according to claim 5,

the predetermined angle is N times (360/M), wherein N is an integer of 1 or more.

7. The manufacturing method according to claim 1 or 2,

in the step (a), M or more annular core pieces are prepared, and in the step (C), the laminated annular core is obtained by laminating the M or more annular core pieces.

8. A method for manufacturing an electric motor, comprising the steps of:

a step of obtaining a stator by using the method for manufacturing a stator according to any one of claims 1 to 7; and

and a step of housing the stator and the rotor in a case.

9. A stator for an electric motor, characterized by comprising:

a laminated body including a plurality of laminated ring-shaped core pieces, each of the plurality of laminated ring-shaped core pieces having a ring-shaped core back and M teeth, the teeth being arranged at substantially equal intervals on an inner circumference of the core back and protruding toward a center of the core back, wherein M is an integer of 2 or more; and

a coil mounted on at least one of the M stacked teeth,

at least one of the plurality of annular core pieces of the laminated body has at least one connecting portion which connects the leading ends of two adjacent teeth to each other and includes a seam,

the joint is formed by two cut surfaces formed by mechanically cutting the coupling portion, and the two cut surfaces are brought into contact with each other again at the joint.

10. The stator according to claim 9,

the first cut surface on one side of the two adjacent teeth of the coupling portion and the second cut surface on the other side of the coupling portion are in contact at the joint.

11. The stator according to claim 10,

each of the annular core pieces has at least one of the connection portions.

12. The stator according to claim 11,

the laminated body has a plurality of coupling portions arranged periodically in the circumferential direction of the core back portion between the plurality of annular core pieces.

13. The stator according to any one of claims 9 to 12,

the laminated body includes M or more annular iron core pieces.

14. An electric motor, characterized in that the electric motor has:

a stator according to any one of claims 9 to 13;

a rotor that rotates relative to the stator; and

a housing that houses the stator and the rotor.