JP7147745B2 - Stator for electric motor and electric motor - Google Patents

Description

The present disclosure relates to stators for electric motors and electric motors.

2. Description of the Related Art In recent years, there has been an increasing demand for low-vibration electric motors (hereinafter simply referred to as "motors"). In particular, motors for electric power steering devices are required to further reduce vibration in order to improve steering feel. As an approach to this, for example, a technique is known that attempts to reduce the vibration of the motor by increasing the rigidity of the stator.

For example, Patent Literature 1 discloses an annular stator including a toothed core in which a plurality of core members are laminated and an annular yoke core fitted to the outer periphery of the toothed core. Each core member has a plurality of teeth and a bridge connecting the tips of two adjacent teeth of the plurality of teeth. As a method of manufacturing a stator, a plurality of core members are formed by punching a steel plate. A toothed core is obtained by laminating a plurality of core members while rotating them one by one by a constant angle. The stator is obtained by press-fitting the toothed core into the inner periphery of the yoke core after installing the windings from the outer peripheral side of the toothed core. According to the stator structure, it is said that magnetic flux leakage is reduced while the mechanical strength of the stator is improved by the bridging portions.

JP-A-3-169235

There is a demand for further improvement in reducing the vibration of motors.

Embodiments of the present disclosure provide a stator capable of reducing motor vibration.

An exemplary stator for a motor of the present disclosure comprises a laminate having a plurality of stacked annular core sheets and having a plurality of laminated teeth; a plurality of windings attached to the plurality of laminated teeth; Each of the core sheets includes an annular core back, a plurality of teeth arranged at equal intervals on the inner periphery of the core back, protruding toward the center of the core back, and connecting the tips of two adjacent teeth. and a connecting portion including a joint.

An exemplary stator for a motor of the present disclosure comprises a laminate having a plurality of stacked annular core sheets and having a plurality of laminated teeth; a plurality of windings attached to the plurality of laminated teeth; Each of the core sheets includes an annular core back, a plurality of teeth arranged at equal intervals on the inner periphery of the core back, protruding toward the center of the core back, and connecting the tips of two adjacent teeth. and a connecting portion including a joint , wherein the connecting portion connects cut surfaces mechanically cut after punching out the annular core sheet into an annular shape and before laminating the annular core sheets. In the connection portion, the first cut surface on one side of the two adjacent teeth and the second cut surface on the other side of the connection portion are in contact with each other at the joint .

FIG. 1 is a cross-sectional view along central axis 500 showing an exemplary structure of motor 100 . FIG. 2 is a perspective view of the laminate 210. FIG. FIG. 3 is a plan view of stator 200 with windings 220 attached to laminate 210 , viewed from the lamination direction of laminate 210 . FIG. 4 is a plan view of the annular core sheet 230 forming the laminate 210 viewed from the lamination direction of the laminate 210. FIG. FIG. 5A is an enlarged schematic diagram showing a pair of adjacent two stacked teeth 212. FIG. FIG. 5B is a schematic diagram showing an enlarged view of one of the plurality of connecting portions 233 between a pair of adjacent two stacked teeth 212. FIG. FIG. 6 is an exploded view of the laminated body 210 obtained by cutting the laminated core back 211 located between a pair of laminated teeth 212 in the y direction and developing the laminated body 210 in the x direction. FIG. 7 is a flow chart showing the flow of the method for manufacturing motor 100 and stator 200. As shown in FIG. FIG. 8A is a schematic diagram showing how a metal mold 800 is used to punch out a plurality of annular core sheets 230 by punching an electromagnetic steel sheet 700 into an annular shape. FIG. 8B is a schematic diagram showing a plurality of annular core sheets 230 formed by punching. FIG. 9 is a schematic diagram showing how the connecting portion 233 is cut using the cutting blade 710. As shown in FIG. FIG. 10 is a schematic diagram showing how a plurality of annular core sheets 230 are laminated while being rotated by a predetermined angle in the circumferential direction. 11A is a schematic diagram showing how the laminated annular core 210 is divided into 12 split cores 250. FIG. FIG. 11B is a schematic diagram showing how the jig 900 is inserted into the slot 214 to divide the laminated annular core 210 . FIG. 11C is a plan view of twelve split cores 250 viewed from the lamination direction of laminated annular core 210 . FIG. 12A is a plan view of split core 250 with windings 220 attached. FIG. 12B is a perspective view of split core 250 with windings 220 attached to laminated teeth 212 . FIG. 13 is a schematic diagram showing how the laminated annular core 210 split into a plurality of split cores 250 is returned to an annular shape using a jig. FIG. 14 is a schematic diagram showing how the cut surfaces of the connecting portion 233 are brought into contact with each other during reassembly. FIG. 15 is a plan view showing an example of stator 200 and rotor 300 included in motor 100. FIG. FIG. 16 is a plan view showing an example of stator 200. As shown in FIG. FIG. 17 is a diagram showing positions where connecting portions 233 are arranged in stator 200. As shown in FIG. 18A and 18B are diagrams showing another example of the position where the connecting portion 233 in the stator 200 is arranged. 19A and 19B are diagrams showing still another example of the position where the connecting portion 233 is arranged in the stator 200. FIG. FIG. 20 is a diagram showing still another example of the position where the connecting portion 233 in the stator 200 is arranged. FIG. 21 shows simulation results of the operation of the motor 100 having the stator structure shown in FIGS. 17-20.

Hereinafter, embodiments of a motor stator and a motor of the present disclosure will be described in detail with reference to the accompanying drawings. However, more detailed description than necessary may be omitted. For example, detailed descriptions of well-known matters and redundant descriptions of substantially the same configurations may be omitted. This is to avoid unnecessary verbosity in the following description and to facilitate understanding by those skilled in the art.

(embodiment)
FIG. 1 is a cross-sectional view along central axis 500 showing an exemplary structure of motor 100 .

The motor 100 according to this embodiment is a so-called inner rotor type motor. The motor 100 is mounted on, for example, an automobile, and is suitably used as a motor for an electric power steering system. In that case, the motor 100 generates driving force for the electric power steering device.

Motor 100 includes stator 200 , rotor 300 , housing 400 , lid portion 420 , lower bearing 430 and upper bearing 440 . Note that the stator 200 is also called an armature.

Housing 400 is a substantially cylindrical casing having a bottom, and accommodates stator 200 , lower bearing 430 and rotor 300 inside. In the center of the bottom of housing 400 is a recess 410 that holds lower bearing 430 . Lid portion 420 is a plate-like member that closes the upper opening of housing 400 . A circular hole 421 that holds the upper bearing 440 is located in the center of the lid portion 420 .

Stator 200 has an annular shape and includes laminates (sometimes called “laminated annular core”) 210 and windings (sometimes called “coils”) 220 . The stator 200 generates magnetic flux according to the drive current. The laminated body 210 is composed of laminated steel plates in which a plurality of steel plates are laminated in a direction along the central axis 500 (the y direction in FIG. 1), and includes an annular laminated core back 211 and a plurality of laminated teeth (teeth) 212 . Laminated core back 211 is fixed to the inner wall of housing 400 . The structure of stator 200 will be described later in detail. Note that the central axis 500 is the rotation axis of the rotor 300 .

The windings 220 are composed of conductive wires (generally copper wires) and are typically attached to each of the lamination teeth 212 of the lamination 210 .

Lower bearing 430 and upper bearing 440 are mechanisms that rotatably support shaft 340 of rotor 300 . For example, as the lower bearing 430 and the upper bearing 440, ball bearings that relatively rotate the outer ring and the inner ring via a spherical body can be used. A ball bearing is shown in FIG.

Outer ring 431 of lower bearing 430 is fixed to recess 410 of housing 400 . The outer ring 441 of the upper bearing 440 is fixed to the edge of the circular hole 421 of the lid portion 420 . Inner rings 432 , 442 of lower bearing 430 and upper bearing 440 , respectively, are fixed to shaft 340 . Therefore, shaft 340 is rotatably supported with respect to housing 400 and lid portion 420 .

Rotor 300 has rotor units 310 , 320 , shaft 340 and cover 350 . Shaft 340 is a substantially columnar member that extends vertically along central axis 500 . Shaft 340 is rotatably supported by lower bearing 430 and upper bearing 440 and can rotate about central axis 500 . The shaft 340 has a head portion 341 at the tip on the lid portion 420 side. The head 341 is connected to a power transmission mechanism such as a gear that transmits driving force to an electric power steering device of an automobile, for example.

Rotor units 310 , 320 and cover 350 rotate together with shaft 340 in the radial interior space of stator 200 . Each rotor unit 310 , 320 has 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 while being turned upside down. The plurality of magnets 333 are arranged at approximately equal intervals along the circumferential direction of the rotor 300 .

Cover 350 is a substantially cylindrical member that holds rotor units 310 and 320 . The cover 350 covers the outer peripheral surfaces of the rotor units 310 and 320 and part of the upper and lower end surfaces. Thereby, the rotor units 310 and 320 are held close to or in contact with each other.

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

Next, the structure of the stator 200 according to this embodiment will be described in detail with reference to FIGS. 2 to 6. FIG.

The stator 200 according to embodiments of the present disclosure may have M (M is an integer equal to or greater than 2) teeth (in other words, M slots). As a specific example, the structure of the stator 200 having 12 teeth (12 slots) will be described below.

FIG. 2 is a perspective view of the laminate 210. FIG. FIG. 3 is a plan view of stator 200 with windings 220 attached to laminate 210 , viewed from the lamination direction of laminate 210 . FIG. 4 is a plan view of the annular core sheet 230 forming the laminate 210 viewed from the lamination direction of the laminate 210. FIG.

Stator 200 comprises laminations 210 and windings 220 . Laminate 210 has 12 laminate teeth 212 and laminate core back 211 . 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 lamination tooth 212 . However, the winding 220 may be attached to at least one of the twelve stacked teeth 212 . For example, windings may be attached to 9 or 6 of the 12 lamination teeth 212 .

A plurality of annular core sheets 230 are laminated in the laminate 210 . The laminate 210 according to this embodiment includes 60 annular core sheets 230 . However, the number of layers to be laminated is not limited to this, and is appropriately determined according to the required characteristics required of the motor, for example. For example, the number of stacked layers may be the same as the number of slots, or may be greater than the number of slots. Of course, the number of stacked layers may be less than the number of slots.

The annular core sheet 230 has an annular core back 231 and 12 teeth 232 arranged at equal intervals on the inner periphery of the core back 231 and projecting toward the center of the core back 231 . In this specification, equal intervals are not limited to strictly equal intervals, and include substantially equal intervals. The tips of the twelve teeth 232 are arranged annularly to form the inner circumference of the annular core seat 230 . The plurality of annular core sheets 230 are stacked in the laminate 210 such that the twelve teeth 232 are aligned between the plurality of annular core sheets 230 . As shown in FIG. 4, the annular core sheet 230 has one connecting portion 233 that connects the tips of a pair of adjacent two teeth 232 and includes a joint. However, the present disclosure is not limited to this, and each annular core sheet 230 may have multiple connecting portions 233 . Also, for example, one annular core sheet 230 has 12 connecting portions 233, which is the same as the number of teeth 232, and the other has no connecting portions 233, and two continuous annular core sheets 230 are repeated in the laminate 210. It does not matter if the layers are stacked on top of each other. In the present disclosure, at least one of the plurality of annular core sheets 230 may have at least one connecting portion 233 . In other words, the laminate 210 should have at least one connecting portion 233 .

FIG. 5A shows an enlarged view of a pair of two adjacent stacked teeth 212 . FIG. 5B shows an enlarged view of one of the plurality of connections 233 between a pair of two adjacent stacking teeth 212 . FIG. 6 is an exploded view of the laminated body 210 obtained by cutting the laminated core back 211 located between a pair of laminated teeth 212 in the y direction and developing the laminated body 210 in the x direction.

A plurality of connecting portions 233 exist between the tips of a pair of adjacent two stacked teeth 212 . In this embodiment, the connecting portion 233 exists between the 60 annular core sheets 230 for every 12 annular core sheets 230 . Five links 233 are present between the tips of a pair of adjacent two stack teeth 212 . Note that this is merely an example, and the connecting portions 233 can be arranged in various patterns. For example, there are five connecting portions 233 between the tips of one pair of adjacent two stacked teeth 212 and four connecting portions between the tips of another pair of adjacent two stacked teeth 212. 233 may be present. Five or more connecting portions 233 are present between the tips of a pair of adjacent two laminated teeth 212, and the connecting portions 233 are present between the tips of another pair of adjacent two laminated teeth 212. It does not have to exist. According to the present disclosure, at least one connection 233 need only be present in the laminate 210 . For example, some annular core sheets 230 may have as many connections 233 as teeth 232 and some annular core sheets may have no connections 233 at all.

As shown in FIG. 5B, connecting portion 233 has a seam 234 . The seams 234 appear to be connected. However, the seam 234 has two cut surfaces 235A, 235B that are mechanically cut as shown in FIG. 9, which will be described in detail later. Specifically, a first cut surface 235A on one side of two adjacent teeth 212 of the connecting portion 233 and a second cut surface 235B on the other side of the connecting portion 233 are in contact with each other at a joint 234. there is 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 non-magnetic material.

As described above, according to the structure of the stator of Patent Document 1, a pair of adjacent two tooth portions are still connected by a continuous bridge portion that is not mechanically cut. Magnetic flux leakage occurs through On the other hand, the connecting portion 233 according to the present disclosure is mechanically cut and is not continuous, but the cut surfaces of the connecting portion 233 are in contact with each other. Therefore, when the magnetic force generated in the radial direction of the stator 200 during rotation of the motor acts on the stator 200 to reduce the distance between the two adjacent teeth 232, the connecting portion 233 suppresses the force. can be done. Thus, the connecting portion 233 can increase the rigidity of the stator (specifically, the strength of the inner peripheral portion of the laminate 210). In addition, magnetic flux leakage through the connecting portion 233 can be suppressed by the mechanically cut surface. Suppression of magnetic flux leakage leads to improvement of cogging torque, for example.

The laminate 210 has a plurality of connecting portions 233 periodically arranged in the circumferential direction of the core backs 231 (in other words, a ring formed by the tips of the plurality of teeth 232) between the plurality of annular core sheets 230. You may have As shown in FIG. 6 , focusing on 12 continuous annular core sheets 230 out of 60 annular core sheets 230 in the laminate 210 , 12 connecting portions 233 are formed between adjacent annular core sheets 230 . can be arranged to lie in two slots 214 adjacent to each other. In other words, the twelve connecting portions 233 may be spirally arranged in the circumferential direction between the plurality of annular core sheets 230 . By adopting the helical structure, the strength of the inner peripheral portion of the laminate 210 can be ensured even if the number of connecting portions 233 is small.

A specific example of a method for manufacturing motor 100 and stator 200 will be described with reference to FIGS.

FIG. 7 shows an exemplary flow of a method for manufacturing motor 100 and stator 200. As shown in FIG. The manufacturing method of the stator 200 according to the present embodiment includes a step of preparing a plurality of annular core sheets 230 (S600), a step of cutting the connecting portion 233 (S610), and a step of obtaining the laminated annular core (laminate) 210 ( S620), a step of dividing laminated annular core 210 into a plurality of split cores 250 (S630), a step of attaching windings 220 to split cores 250 (S640), and reassembling a plurality of split cores 250 to form stator 200. and a step of obtaining (S650). In addition to these steps, the method of manufacturing motor 100 further includes a step of housing stator 200 and rotor 300 in housing 400 (S660).

First, in step S600, a plurality of annular core sheets 230 shown in FIG. 4 are prepared. For example, 12 or more annular core sheets 230 are provided, the same number as teeth 232 . Note that, as described above, the number of sheets to be prepared is not limited to this, and is appropriately determined according to the required characteristics required of the motor 100, for example. To obtain the laminate 210 shown in FIG. 2, for example, 60 annular core sheets 230 are prepared. Each annular core sheet 230 includes a core back 231 , twelve teeth 232 , and a connecting portion 233 connecting the tips of a pair of two adjacent teeth 232 . Note that at step 600, the connecting portion 233 does not have the joint 234 yet. At least one of the plurality of annular core sheets 230 should have at least one connecting portion 233, and the required number of annular core sheets 230 may be prepared.

FIG. 8A schematically shows how a metal mold 800 is used to punch out an electromagnetic steel sheet 700 into an annular shape to form a plurality of annular core sheets 230 . FIG. 8B schematically shows a plurality of annular core sheets 230 formed by stamping. As a method of preparing the plurality of annular core sheets 230, as shown in the figure, the electromagnetic steel sheet 700 is placed on a die 810, and the electromagnetic steel sheet 700 is punched into an annular shape using a die (punch) 800 to form a plurality of annular cores. Sheet 230 may be molded. Other than press working, for example, wire electric discharge machining and laser machining can also be used. Alternatively, for example, a supplier may supply a plurality of annular core sheets 230 as parts. In the present embodiment, the electromagnetic steel sheet 700 is punched into an annular shape using a die 800 to form 60 annular core sheets 230 .

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

FIG. 9 schematically shows how the connecting portion 233 is cut using the cutting blade 710 . For example, a cutting blade 710 is used to mechanically cut approximately the center of the connecting portion 233 to form the seam 234 . As a result, a first cut surface 235A is formed on one side of the two adjacent teeth 232 of the connecting portion 233, and a second cut surface 235B is formed on the other side of the connecting portion 233. As shown in FIG. The connecting portion 233 is mechanically cut for each annular core sheet 230 to form joints 234 in all the connecting portions 233 included in the plurality of annular core sheets 230 . Moreover, in order to divide the laminated annular core 210 in step S630, which will be described later, it is preferable to make a cut 237 substantially in the center of the core back 231 between two adjacent teeth 232, as shown in FIG. .

Next, in step S 620 , a plurality of annular core sheets 230 are laminated to obtain a laminated annular core 210 having 12 laminated teeth 212 . In this embodiment, after stacking 60 annular core sheets 230, the plurality of annular core sheets 230 are fixed by caulking, adhesion, or laser welding, for example. Thereby, a laminated annular core 210 having 12 laminated teeth 212 is obtained. Note that the laminated annular core 210 corresponds to the laminated body 210 described above.

FIG. 10 schematically shows how a plurality of annular core sheets 230 are laminated while being rotated in the circumferential direction by a predetermined angle for each sheet. Note that FIG. 10 shows two of the 60 annular core sheets 230 . It is preferable to stack the plurality of annular core sheets 230 by rotating each sheet by a predetermined angle in the circumferential direction. Such lamination is commonly referred to as "transpilation". Since the connecting portion 233 is spirally arranged by rolling, the strength of the inner peripheral portion of the laminated annular core 210 can be ensured.

The predetermined angle is (360/M) times N (N is an integer equal to or greater than 1). As mentioned above, M indicates the number of teeth (or slots). When M=12, the predetermined angle is an integral multiple of 30°. In this embodiment, as shown in FIG. 10, 60 annular core sheets are laminated by rotating each sheet clockwise by 30°. As a result, an arrangement pattern (that is, a spiral structure) of the connecting portions 233 as shown in FIG. 6 is obtained in the laminated annular core 210 . Note that the y-direction shown in FIG. 10 is a direction parallel to the central axis of the laminated annular core 210 . Sixty annular core sheets 230 are stacked along the y-direction so that twelve teeth 232 are aligned.

Next, in step S630, the laminated annular core 210 is divided into 12 or less divided cores 250. As shown in FIG.

FIG. 11A schematically shows how the laminated annular core 210 is divided into 12 split cores 250 . FIG. 11B schematically shows how the jig 900 is inserted into the slot 214 to divide the laminated annular core 210 . FIG. 11C is a plan view of twelve split cores 250 viewed from the lamination direction of laminated annular core 210 . FIG. 11B shows an enlarged view of part of the laminated annular core 210 . A jig 900 is inserted into the slot 214, for example, in the direction of the arrow shown in FIG. 11A. Specifically, as shown in FIG. 11B, a jig 900 is inserted into the slot 214 to apply a force in the circumferential direction of the laminated annular core 210, thereby separating the laminated annular core 210 into one laminated tooth each. 212 into 12 split cores 250 . By forming the cut 237 in advance in the core back 231 of each annular core sheet 230 in step S610, the laminated annular core 210 can be easily divided. The jig 900 may be inserted into each of the plurality of slots 214 for division, or the jig 900 may be inserted into a plurality of slots at the same time for division.

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

Next, in step S640, the winding 220 is attached to at least one of the twelve split cores 250. As shown in FIG.

FIG. 12A is a plan view of split core 250 with windings 220 attached. FIG. 12B is a perspective view of split core 250 with windings 220 attached to laminated teeth 212 . In this embodiment, an insulating member 260 is attached to each of the laminated teeth 212 of the twelve split cores 250, and the winding 220 is attached thereon (so-called concentrated winding). Spindle winding and nozzle winding, for example, can be used as a method of winding the conductor around the split core 250 . Note that it is not necessary to attach the windings 220 to all the split cores 250 (laminated teeth 212), and the windings 220 may be attached to the required number of split cores 250 according to the design specifications. In other words, the winding 220 should be attached to at least one laminated tooth 212 of the twelve split cores 250 . For example, the windings 220 may be attached to nine laminated teeth 212 out of twelve split cores 250 .

Next, in step S650, a plurality of split cores 250 each having windings 220 attached thereto are reassembled to obtain annular stator 200. FIG.

FIG. 13 schematically shows how the laminated annular core 210 split into a plurality of split cores 250 is returned to an annular shape using a jig (not shown). FIG. 14 schematically shows how the cut surfaces of the connecting portion 233 are brought into contact with each other during reassembly. "Reassembling" means fixing the plurality of split cores 250 to each other and restoring the shape (that is, the annular shape) before splitting. Specifically, after the windings 220 are attached, the annular stator 200 is produced by reassembling the twelve split cores 250 . Each cut surface of split core 250 has an uneven shape. When the cut surfaces of two adjacent split cores 250 are brought into contact with each other, the shapes of the two cut surfaces match each other, and the split cores 250 can be returned to the positional relationship before cutting. During the reassembly, the cut surfaces of the connecting portion 233 cut in step S610 are brought into contact with each other. By returning the split cores 250 to the positional relationship before cutting, the cut surfaces of the connecting portions 233 can also be aligned. In this embodiment, the twelve split cores 250 are reassembled using jigs. At that time, as shown in FIG. 14, the cut surfaces (first and second cut surfaces 235A, 235B) of the 60 mechanically cut connecting portions 233 are brought into contact with each other.

The plurality of split cores 250 are fixed by, for example, adhesion or laser welding. This fixation takes into account (1) circumferential variation and (2) axial height variation of the laminated annular core 210 among the plurality of laminated teeth 212 . It should be noted that each cut surface may be coated with a non-magnetic material after the connecting portion 233 is cut and before the cut surfaces are brought into contact with each other. Alternatively, the cut surfaces may be brought into contact with each other via an adhesive.

As in Patent Document 1, the tooth core (corresponding to the annular core sheet 230 with the core back 231 removed) and the yoke core (corresponding to the core back 231) are prepared as independent members. In that case, for example, variations (errors) in punching due to the die may occur among the teeth 232, so during assembly (especially after the tooth core is press-fitted into the yoke core), the tips of the teeth 232 Misalignment occurs and it becomes difficult to bring the tips of two adjacent teeth into contact. On the other hand, according to the present embodiment, the connecting portion 233 is cut after the annular core sheet 230 including the core back 231 and the connecting portion 233 is punched into an annular shape. Since the core back 231 and the plurality of teeth 232 are integrated, the cut surfaces can maintain contact with each other even after the connecting portion 233 is cut. Further, since a plurality of laminated annular core sheets 230 are laminated in this state, the cut surfaces can be kept in contact with each other until the laminated annular core 210 is split (until just before splitting). In addition, since no press-fitting operation occurs, the tip of the tooth 232 does not shift in position during press-fitting. Therefore, when the split cores 250 are reassembled, the cut surfaces of the cut connecting portions 233 can be brought into contact with each other.

Further in the method of manufacturing motor 100, stator 200 and rotor 300 are accommodated in housing 400 in step S660.

An example of a method for 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 the rotor core 331 inserted into the mold to integrate the rotor core 331 and the resin. When the resin is cooled and solidified, it becomes the magnet holder 332 . Next, the magnet 333 is inserted into the integrated rotor core 331 and magnet holder 332 . Thereby, 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 (eg, a ball bearing) is placed in the recess 410 of the housing 400 . Next, after the stator 200 is housed in the housing 400 , the shaft 340 is inserted into the lower bearing 430 and the rotor 300 integrated with the shaft 340 is arranged in the internal space of the stator 200 . Finally, an upper bearing 440 (for example, a ball bearing) is placed in the circular hole 421 of the lid portion 420 to close the upper opening of the housing 400 with the lid portion 420 .

Note that part of the manufacturing process described above can be replaced by a known manufacturing method (for example, the method disclosed in Patent Document 1).

According to the method of manufacturing the motor 100 and the stator 200 according to the present embodiment, by forming the joints 234 in the connecting portions 233 to divide the laminated annular core 210, a plurality of laminated teeth can be formed without being affected by the connecting portions 233. The winding 220 can be easily attached to the winding 212, and the work of press-fitting into the laminated core back 211 as in Patent Document 1, for example, becomes unnecessary. As a result, not only is the assembly of the stator 200 easier, but contamination during press-fitting can be prevented. Furthermore, since only the connecting portion 233 is not connected in the assembly process, deformation of the connecting portion 233 can be prevented.

As described above, according to the present embodiment, the connecting portion 233 can increase the rigidity of the stator 200 and reduce the vibration of the motor 100 . Moreover, magnetic flux leakage through the connecting portion 233 can be reduced by having the mechanically cut surface of the connecting portion 233 .

Next, a structure for more effectively reducing vibration of motor 100 in motor 100 having connecting portion 233 will be described. Here, in the motor 100 in which the stator 200 has 12 laminated teeth 212 and the rotor has 8 magnets 333, a method of arranging the connecting portions 233 for more effectively reducing vibration will be described.

FIG. 15 is a plan view showing an example of stator 200 and rotor 300 included in motor 100. FIG. FIG. 16 is a plan view showing an example of stator 200. As shown in FIG. 15 and 16 omit the illustration of the windings 220 for the sake of clarity. In this example, stator 200 has twelve stacked teeth 212 . The rotor 300 has eight magnets 333 . A structure with such a number of laminated teeth 212 and magnets 333 is sometimes referred to as a 12S8P (12 slot 10 pole).

In this example, the motor 100 is a three-phase motor having windings of three phases (U-phase, V-phase, W-phase). As shown in FIG. 16, the 12 stacked teeth 212 have U, V, W, U, V, W, U, V, W, U, V, and W phases in this order. is assigned. Each of the plurality of annular core sheets 230 included in stator 200 includes twelve teeth 232 . The 12 teeth 232 of these annular core sheets 230 are also assigned the U-phase, V-phase, and W-phase in the order shown in FIG.

FIG. 17 is a diagram showing positions where connecting portions 233 are arranged in stator 200. As shown in FIG. Along the horizontal direction of FIG. 17, 12 laminated teeth 212 to which U-phase, V-phase, and W-phase are assigned are arranged. Numerical values 0, 30, 60, . Since the number of laminated teeth 212 is 12, the laminated teeth 212 are arranged on the stator 200 at intervals of 30 degrees. In this example, stator 200 includes twelve annular core sheets 230 . Numbers 1, 2, 3, . . . , 12 aligned in the vertical direction in FIG. Moreover, the laminated body 210 of the stator 200 has a structure in which twelve annular core sheets 230 are rotated in the circumferential direction by 30 degrees for each sheet and laminated. That is, the angle of transduction is 30 degrees. In this example, the number of annular core sheets 230 is 12, but this number is an example, and the number of sheets is appropriately determined according to the required characteristics of the motor. For example, 60 annular core sheets 230 may be stacked as described above.

In the structure of the stator 200 shown in FIG. 17, each of the 12 annular core sheets 230 has two connecting portions 233 . A black square portion in FIG. 17 represents the connecting portion 233 . Two connecting portions 233 provided in each of the twelve annular core sheets 230 connect teeth to which two phases out of the three phases of U phase, V phase, and W phase are assigned.

Among the twelve annular core sheets 230, two connecting portions 233 provided in the uppermost annular core sheet 230 have teeth 232 to which the W phase is assigned and teeth 232 to which the U phase is assigned. are connected. The two connecting portions 233 are separated by 180 degrees. Similarly, two connecting portions 233 provided in each of the fourth, seventh, and tenth annular core sheets 230 from the top connect the tooth 232 to which the W phase is assigned and the tooth 232 to which the U phase is assigned. is doing.

Among the twelve annular core sheets 230, the annular core sheet 230 positioned second from the top has two connecting portions 233, which are a tooth 232 assigned with a U phase and a tooth 232 assigned with a V phase. are concatenated. The two connecting portions 233 are separated by 180 degrees. Similarly, two connecting portions 233 provided in each of the fifth, eighth, and eleventh annular core sheets 230 from the top connect the tooth 232 assigned with the U phase and the tooth 232 assigned with the V phase. is doing.

Among the 12 annular core sheets 230, the annular core sheet 230 located third from the top has two connecting portions 233, which are a tooth 232 assigned with the V phase and a tooth 232 assigned with the W phase. are concatenated. The two connecting portions 233 are separated by 180 degrees. Similarly, two connecting portions 233 provided in each of the sixth, ninth, and twelfth annular core sheets 230 from the top connect the tooth 232 assigned with the V phase and the tooth 232 assigned with the W phase. is doing.

The inventor of the present application performed a simulation of the operation of the motor 100 having the stator structure shown in FIG. 17, and examined the results. Details of the operation of motor 100 will be described later with reference to FIG.

18A and 18B are diagrams showing another example of the position where the connecting portion 233 in the stator 200 is arranged. Along the horizontal direction of FIG. 18, 12 laminated teeth 212 to which U-phase, V-phase, and W-phase are assigned are arranged. The numbers 0, 30, 60, . . . , 330 arranged in the horizontal direction and the numbers 1, 2, 3, . be. The laminated body 210 of the stator 200 has a structure in which 12 annular core sheets 230 are rotated in the circumferential direction by 30 degrees and laminated.

In the structure of the stator 200 shown in FIG. 18, each of the twelve annular core sheets 230 has four connecting portions 233 . A black square portion in FIG. 18 represents the connecting portion 233 . The four connecting portions 233 provided on each of the twelve annular core sheets 230 connect teeth to which two of the three phases of U, V, and W are assigned.

Of the twelve annular core sheets 230, the four connecting portions 233 of the uppermost annular core sheet 230 have teeth 232 assigned with the W phase and teeth 232 assigned with the U phase. are connected. The four connecting portions 233 are arranged at intervals of 90 degrees. Similarly, four connecting portions 233 provided in each of the fourth, seventh, and tenth annular core sheets 230 from the top connect the tooth 232 assigned with the W phase and the tooth 232 assigned with the U phase. is doing.

Among the 12 annular core sheets 230, the annular core sheet 230 positioned second from the top has four connecting portions 233, which are composed of a tooth 232 assigned with a U phase and a tooth 232 assigned with a V phase. are concatenated. The four connecting portions 233 are arranged at intervals of 90 degrees. Similarly, the four connecting portions 233 provided in each of the fifth, eighth, and eleventh annular core sheets 230 from the top connect the tooth 232 assigned with the U phase and the tooth 232 assigned with the V phase. is doing.

Among the 12 annular core sheets 230, the annular core sheet 230 located third from the top has four connecting portions 233, which are composed of a tooth 232 assigned with the V phase and a tooth 232 assigned with the W phase. are concatenated. The four connecting portions 233 are arranged at intervals of 90 degrees. Similarly, the four connecting portions 233 provided in each of the sixth, ninth, and twelfth annular core sheets 230 from the top connect the tooth 232 assigned with the V phase and the tooth 232 assigned with the W phase. is doing.

The inventor of the present application performed a simulation of the operation of the motor 100 having the stator structure shown in FIG. 18, and examined the results. Details of the operation of motor 100 will be described later with reference to FIG.

19A and 19B are diagrams showing still another example of the position where the connecting portion 233 is arranged in the stator 200. FIG. Along the horizontal direction of FIG. 19, 12 laminated teeth 212 to which U-phase, V-phase, and W-phase are assigned are arranged. The numbers 0, 30, 60, . . . , 330 arranged in the horizontal direction and the numbers 1, 2, 3, . be. The laminated body 210 of the stator 200 has a structure in which 12 annular core sheets 230 are rotated in the circumferential direction by 30 degrees and laminated.

In the structure of the stator 200 shown in FIG. 19, each of the 12 annular core sheets 230 has one connecting portion 233 . A black square portion in FIG. 19 represents the connecting portion 233 . One connecting portion 233 provided in each of the twelve annular core sheets 230 connects teeth to which two phases out of three phases of U phase, V phase, and W phase are assigned.

Of the twelve annular core sheets 230, one connecting portion 233 of the uppermost annular core sheet 230 has a tooth 232 assigned with the W phase and a tooth 232 assigned with the U phase. are connected. Similarly, one connecting portion 233 provided in each of the fourth, seventh, and tenth annular core sheets 230 from the top connects the tooth 232 assigned with the W phase and the tooth 232 assigned with the U phase. is doing.

One connecting portion 233 of the annular core sheet 230 located second from the top among the twelve annular core sheets 230 has a tooth 232 assigned with the U phase and a tooth 232 assigned with the V phase. are concatenated. Similarly, one connecting portion 233 provided in each of the fifth, eighth, and eleventh annular core sheets 230 from the top connects the tooth 232 assigned with the U phase and the tooth 232 assigned with the V phase. is doing.

Of the twelve annular core sheets 230, one connecting portion 233 provided in the third annular core sheet 230 from the top has a tooth 232 assigned with the V phase and a tooth 232 assigned with the W phase. are concatenated. Similarly, one connecting portion 233 provided in each of the sixth, ninth, and twelfth annular core sheets 230 from the top connects the tooth 232 assigned with the V phase and the tooth 232 assigned with the W phase. is doing.

The inventor of the present application conducted a simulation of the operation of the motor 100 having the stator structure shown in FIG. 19, and examined the results. Details of the operation of motor 100 will be described later with reference to FIG.

FIG. 20 is a diagram showing still another example of the position where the connecting portion 233 in the stator 200 is arranged. Along the horizontal direction of FIG. 20, 12 laminated teeth 212 to which U-phase, V-phase, and W-phase are assigned are arranged. The numbers 0, 30, 60, . . . , 330 arranged in the horizontal direction and the numbers 1, 2, 3, . be. The laminated body 210 of the stator 200 has a structure in which 12 annular core sheets 230 are rotated in the circumferential direction by 30 degrees and laminated.

In the structure of the stator 200 shown in FIG. 20, each of the twelve annular core sheets 230 has three connecting portions 233 . A black square portion in FIG. 20 represents the connecting portion 233 .

Of the twelve annular core sheets 230, one of the three connecting portions 233 provided in the uppermost annular core sheet 230 has a tooth 232 assigned with the W phase and a tooth 232 assigned with the U phase. and the teeth 232 are connected. Another one of the three connecting portions 233 connects the tooth 232 assigned the U phase and the tooth 232 assigned the V phase. Still another one of the three connecting portions 233 connects the tooth 232 assigned the V phase and the tooth 232 assigned the W phase. The three connecting portions 233 are arranged at intervals of 120 degrees. Similarly to the uppermost annular core sheet 230, the three connecting portions 233 provided in each of the second to twelfth annular core sheets 230 counted from the top are also arranged at intervals of 120 degrees. The cage connects tooth to tooth. The 12 annular core sheets 230 are laminated while rotating each sheet by 30 degrees in the circumferential direction. Therefore, the positions of the connecting portions 233 of the annular core sheets 230 adjacent to each other are shifted by 30 degrees.

FIG. 21 shows simulation results of the operation of the motor 100 having the stator structure shown in FIGS. 17-20. The vertical axis in FIG. 21 represents acceleration, and the horizontal axis represents angle.

A solid line 301 indicates the acceleration of the rotor 300 of the motor 100 having the stator structure shown in FIG. In the stator structure shown in FIG. 19, each of the twelve annular core sheets 230 has one connecting portion 233 .

A solid line 302 indicates the acceleration of the rotor 300 of the motor 100 having the stator structure shown in FIG. In the stator structure shown in FIG. 17, each of the twelve annular core sheets 230 has two connecting portions 233 .

A solid line 303 indicates the acceleration of the rotor 300 of the motor 100 having the stator structure shown in FIG. In the stator structure shown in FIG. 20 , each of the twelve annular core sheets 230 has three connecting portions 233 .

A solid line 304 indicates the acceleration of the rotor 300 of the motor 100 having the stator structure shown in FIG. In the stator structure shown in FIG. 18, each of the twelve annular core sheets 230 has four connecting portions 233 . A solid line 30N indicates the acceleration of the rotor 300 of the motor 100 without the connecting portion 233. FIG.

As indicated by the solid line 301 , in the motor 100 in which each of the annular core sheets 230 has one connecting portion 233 , the fluctuation range of acceleration during one rotation of the rotor 300 is large. Further, as indicated by the solid line 303, even in the motor 100 in which each of the annular core sheets 230 has three connecting portions 233, the fluctuation range of the acceleration during one rotation of the rotor 300 is large. When the fluctuation width of the acceleration during one rotation of the rotor 300 is large, the vibration of the motor 100 is large. Also, although not shown, in these structures, the torque ripple, which is the variation width of the torque, increases.

On the other hand, as indicated by the solid line 302, in the motor 100 in which each of the annular core sheets 230 has two connecting portions 233, the fluctuation range of the acceleration during one rotation of the rotor 300 is small. Further, as indicated by the solid line 304, even in the motor 100 in which each of the annular core sheets 230 has four connecting portions 233, the fluctuation range of the acceleration during one rotation of the rotor 300 is small. Therefore, it can be seen that the structure shown in FIGS. 17 and 18 can reduce the vibration of the motor 100. FIG. Although not shown, the structure shown in FIGS. 17 and 18 can reduce torque ripple.

Vibration of motor 100 can be more effectively reduced by providing motor 100 with the stator structure shown in FIGS. 17 and 18 in this manner.

Embodiments of the present disclosure can be widely used for various motors used in vacuum cleaners, dryers, ceiling fans, washing machines, refrigerators, electric power steering devices, and the like.

100: Motor, 200: Stator, 210: Laminate (Laminated Annular Core), 211: Laminated Core Back, 212: Laminated Tooth, 214: Slot, 220: Winding, 230: Annular Core Sheet, 231: Core Back, 232 : tooth 233: connecting portion 234: joint 235A: first cut surface 235B: second cut surface 237: notch 250: split core 260: insulating member 300: rotor 400: housing

Claims (12)

a laminated body in which a plurality of annular core sheets are laminated and which has a plurality of laminated teeth;
a plurality of windings attached to a plurality of laminated teeth;
with
Each of the plurality of annular core sheets,
an annular core back;
a plurality of teeth arranged at equal intervals on the inner periphery of the core back and protruding toward the center of the core back;
a connecting portion that connects the tips of two adjacent teeth and includes a joint;
with
The connecting portion has a cut surface at the seam that is mechanically cut after punching the annular core sheet into an annular shape and before stacking the annular core sheets,
A stator for an electric motor , wherein in the connecting portion, a first cut surface on one side of the two adjacent teeth and a second cut surface on the other side of the connecting portion are in contact with each other at the joint . 2. The stator of claim 1, wherein each of said plurality of annular core sheets has a plurality of connecting portions. The plurality of windings includes three-phase windings,
the three phases include a first phase, a second phase, and a third phase;
the plurality of teeth of each of the plurality of annular core sheets are assigned the first phase, the second phase and the third phase;
The plurality of annular core sheets includes a first annular core sheet,
3. The stator according to claim 2 , wherein each of the plurality of connecting portions of the first annular core sheet connects a tooth assigned with the first phase and a tooth assigned with the second phase. The plurality of annular core sheets includes a second annular core sheet,
4. The stator according to claim 3 , wherein each of the plurality of connecting portions of the second annular core sheet connects a tooth assigned with the second phase and a tooth assigned with the third phase. The plurality of annular core sheets includes a third annular core sheet,
5. The method according to claim 3 , wherein each of the plurality of connecting portions of the third annular core sheet connects a tooth to which the third phase is assigned and a tooth to which the first phase is assigned. stator. 6. A stator according to any preceding claim, wherein the number of laminated teeth is twelve. 7. The stator according to any one of claims 1 to 6 , wherein the laminated body has a structure in which the plurality of annular core sheets are rotated in a circumferential direction by a predetermined angle and laminated one by one. 8. The stator according to any one of claims 1 to 7 , wherein the laminated body has a structure in which the plurality of annular core sheets are laminated while rotating each sheet by 30 degrees in the circumferential direction. a stator according to any one of claims 1 to 8 ;
a rotor rotating with respect to the stator;
a housing that houses the stator and the rotor;
an electric motor. the stator comprises 12 of the laminated teeth;
10. The electric motor of Claim 9 , wherein the rotor comprises eight magnets. 11. The electric motor according to claim 10 , wherein the laminated body has a structure in which the plurality of annular core sheets are laminated while rotating each sheet by 30 degrees in the circumferential direction. A method for manufacturing a stator for an electric motor, comprising:
In the step (A) of preparing a plurality of annular core sheets, each of the plurality of annular core sheets is arranged on an annular core back and an inner circumference of the core back at substantially equal intervals. M (M is an integer of 2 or more) teeth projecting toward the center, and at least one of the plurality of annular core sheets has at least a connecting portion that connects tips of two adjacent teeth. A step (A) comprising one;
A step (B) of cutting the connecting portion;
a step (C) of laminating the plurality of annular core sheets to obtain a laminated annular core having M laminated teeth;
(D) dividing the laminated annular core into a plurality of split cores of M or less each including at least one laminated tooth;
(E) attaching a winding to at least one of the plurality of split cores;
A step (F) of forming an annular stator by reassembling the plurality of split cores after attaching the windings, wherein the stator cut in the step (B) during the reassembling is performed. A step (F) of bringing the cut surfaces of the connecting portions into contact with each other;
A manufacturing method comprising:

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