JP7067564B2 - Stator core manufacturing method - Google Patents

Description

The present invention relates to a stator core manufacturing method.

As a method of manufacturing a stator core of a motor, a method of punching a steel plate into the shape of a stator core by a pressing device or the like and laminating a plurality of punched molded steel plates in the thickness direction is known.

As a method for manufacturing a stator core as described above, for example, a press working method disclosed in Patent Document 1 is known. This press working method includes a lansing step in which a die is placed above the work material and a punch is placed below the work material, and the punch is struck against the work material from below to push the blank material upward. Then, it includes a pushback step of pushing the blank material extruded upward back to the original position in the work material.

In the press working method disclosed in Patent Document 1, after the blank material is pushed upward by a punch in the lansing step, the pushed portion is returned to the original position of the work material in the pushback step, so that the pushback step is performed. A notch is formed between the blank material obtained after the above process and the strip material (the portion of the work material that has not been punched). Moreover, in the press working method, since the blank material is pushed upward in the lansing process, the notch formed between the blank material and the strip material obtained after the pushback process is trumpeted toward the strip material side as it goes upward. It is expanded and formed like a shape.

Japanese Unexamined Patent Publication No. 61-209732

By the way, as disclosed in Patent Document 1 described above, when a pushback process is performed in which a part of the work material is punched out and then the punched out portion is returned to the original position of the work material, the punching is performed. The part is separated from the other parts. Therefore, if vibration or an external force is applied to the punched-out portion after the pushback process, the punched-out portion may fall off.

Further, when the portion punched by the pushback process is cut at a position closer to the punched portion than the notch formed by the bushback process, the portion between the notch and the cutting position may fall off. ..

By the way, as a method of manufacturing a stator core, when a stator coil is wound around a teeth of a stator core of a motor, the stator core is divided into a plurality of parts in the circumferential direction, whereby the stator coil with respect to the teeth is formed. A method of improving work efficiency while increasing the number of windings is also known. When the stator core is divided in the circumferential direction in this way, the stator core steel plate constituting the stator core of the motor is formed by the above-mentioned pushback processing, and the stator core steel plate is laminated in the thickness direction. A method of dividing the laminate obtained by the above method into a plurality of divided cores can be considered.

When the split core is manufactured by the above method, the split yoke pieces constituting the split yoke of the split core are formed on the steel sheet by pushback processing. That is, by pushback processing, the outer periphery of the split yoke piece is formed as a notch in the steel sheet. In the stator core steel plate, the tooth pieces constituting the teeth of the split core extend inward in the radial direction, so that when vibration or an external force is applied to the teeth pieces, the outer periphery of the split yoke pieces is covered. It is easy for the notch to fall off.

An object of the present invention is to provide a stator core manufacturing method capable of preventing a portion punched out by pushback processing from falling off.

The stator core manufacturing method according to the embodiment of the present invention is a method for manufacturing a stator core in which a split core in which a plurality of plate-shaped split core pieces are laminated is arranged in an annular shape about a central axis. This stator core manufacturing method is a fan shape centered on the central axis in a plan view by a pushback process in which a part of the steel sheet is punched out in the thickness direction and then the punched out part is returned to the original position of the steel sheet. There are, a plurality of divided core piece forming portions to be the divided core pieces are formed in an annular shape on the steel sheet, and the divided core piece forming portion is formed on the steel plate on the radial outside of the divided core piece forming portion and on the steel sheet. It has a pushback step of forming a connecting portion that connects parts other than the portion with a portion thereof.

According to the stator core manufacturing method according to the embodiment of the present invention, it is possible to prevent the portion punched out by the pushback process from falling off.

FIG. 1 is a diagram schematically showing a schematic configuration of a motor according to an embodiment in a cross section including a central axis. FIG. 2 is a perspective view showing a schematic configuration of the stator core. FIG. 3 is a flowchart showing a method of manufacturing a stator core. FIG. 4 is a plan view of the electrical steel sheet before forming the divided core piece molded portion. FIG. 5 is a plan view showing a schematic configuration of a molded steel sheet. FIG. 6 is a diagram schematically showing (a) a state in which the first tool is moved with respect to the second tool and (b) a state in which the first tool is returned to the original position in pushback machining. be. FIG. 7 is a perspective view showing a schematic configuration of a molded steel sheet laminate in which a plurality of molded steel sheets are laminated in the thickness direction. FIG. 8 is a top view showing a schematic configuration of the stator core laminate after the cutting process. FIG. 9 is a plan view showing a state in which the molded steel plate laminate is cut along the cutting line. FIG. 10 is a perspective view showing a state in which the stator core laminate is divided into a plurality of divided cores. FIG. 11 is an enlarged plan view showing the configuration of the connecting portion in the molded steel sheet according to the other embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The same or corresponding parts in the drawings are designated by the same reference numerals and the description thereof will not be repeated. Further, the dimensions of the constituent members in each drawing do not faithfully represent the actual dimensions of the constituent members, the dimensional ratio of each constituent member, and the like.

In the following description, the direction parallel to the central axis of the rotor is "axial direction", the direction orthogonal to the central axis is "diametrical direction", and the direction along the arc centered on the central axis is "circumferential direction". Each is called. However, the definition of this direction does not intend to limit the direction when the motor according to the present invention is used.

Further, in the following description, the expressions such as "fixed", "connected" and "attached" (hereinafter referred to as "fixed") are used not only when the members are directly fixed to each other but also via other members. Including the case where it is fixed. That is, in the following description, the expression such as fixing includes the meaning of direct and indirect fixing between members.

(Structure of Motor) FIG. 1 shows a schematic configuration of a motor 1 according to an embodiment of the present invention. The motor 1 includes a rotor 2, a stator 3, a housing 4, and a lid plate 5. The rotor 2 rotates about the central axis P with respect to the stator 3. In the present embodiment, the motor 1 is a so-called inner rotor type motor in which the rotor 2 is rotatably arranged around the central axis P in the cylindrical stator 3.

The rotor 2 includes a shaft 20, a rotor core 21, and a magnet 22. The rotor 2 is arranged radially inside the stator 3 and is rotatable with respect to the stator 3.

In this embodiment, the rotor core 21 has a cylindrical shape extending along the central axis P. The rotor core 21 is configured by laminating a plurality of electromagnetic steel sheets formed in a predetermined shape in the thickness direction.

A shaft 20 extending along the central axis P is fixed to the rotor core 21 in a state of penetrating in the axial direction. As a result, the rotor core 21 rotates together with the shaft 20. Further, in the present embodiment, a plurality of magnets 22 are arranged at predetermined intervals in the circumferential direction on the outer peripheral surface of the rotor core 21. The magnet 22 may be a ring magnet connected in the circumferential direction.

The stator 3 is housed in the housing 4. In the present embodiment, the stator 3 has a cylindrical shape, and the rotor 2 is arranged inside in the radial direction. That is, the stator 3 is arranged so as to face the rotor 2 in the radial direction. The rotor 2 is rotatably arranged about the central axis P inside the stator 3 in the radial direction.

The stator 3 includes a stator core 31, a stator coil 36, and a bracket 37. In the present embodiment, the stator core 31 has a cylindrical shape extending in the axial direction. The stator core 31 has a plurality of electrical steel sheets formed in a predetermined shape and laminated in the thickness direction. In this embodiment, the stator core 31 has a plurality of split cores 32 as described later.

As shown in FIG. 2, the stator core 31 has a plurality of teeth 31b extending radially inward from the tubular yoke 31a. The stator coil 36 is wound on a bracket 37 made of an insulating material (for example, an insulating resin material) mounted on the teeth 31b of the stator core 31. The bracket 37 is arranged on both end faces in the axial direction of the stator core 31.

The stator core 31 has a plurality of split cores 32 arranged in an annular shape about the central axis P. In the example shown in FIG. 2, the stator core 31 has 12 split cores 32. Each split core 32 has a split yoke portion 32a that forms a part of the cylindrical yoke 31a, and one tooth 31b.

The number of split cores 32 constituting the stator core 31 is appropriately determined according to the number of teeth 31b. That is, if the number of teeth of the stator core is more than 12, the number of split cores is more than 12. On the other hand, if the number of teeth of the stator core is less than 12, the number of split cores is less than 12.

The divided core 32 has a plate-shaped divided core piece 33 in which a plurality of sheets are laminated. In the example shown in FIG. 2, the plurality of divided core pieces 33 constituting the divided core 32 have the same shape. The split core piece 33 has a split yoke piece 33a forming a part of the split yoke portion 32a and a teeth piece 33b forming a part of the teeth 31b. The plurality of divided core pieces 33 are connected to each other by the caulking portions 33c provided on the divided yoke pieces 33a and the teeth pieces 33b, respectively, in a state of being laminated in the thickness direction.

The circumferential end of the split yoke portion 32a and the circumferential end of the split yoke portion 32a adjacent to the split yoke portion 32a in the circumferential direction are in contact with each other. As a result, the annular yoke 31a of the stator core 31 is configured by the split yoke portions 32a in the plurality of split cores 32.

The housing 4 has a cylindrical shape and extends along the central axis P. In the present embodiment, the housing 4 has a cylindrical shape having an internal space capable of accommodating the rotor 2 and the stator 3 inside. The housing 4 has a cylindrical side wall 4a and a bottom portion 4b that covers one axial end of the side wall 4a. The axially opposite opening of the housing 4 is covered by the lid plate 5. The housing 4 and the lid plate 5 are made of, for example, a material containing iron. By covering the opening of the bottomed cylindrical housing 4 with the lid plate 5, an internal space is formed inside the housing 4. Although not particularly shown, the lid plate 5 may be fixed to the housing 4 by, for example, a bolt or a method such as press fitting or bonding. The housing 4 and the lid plate 5 are not limited to the material containing iron, and may be made of other materials such as aluminum (including an aluminum alloy).

(Method for Manufacturing Stator Core) Next, a method for manufacturing the stator core 31 having the above-described configuration will be described with reference to FIGS. 3 to 10.

FIG. 3 is a flowchart showing an example of a method for manufacturing the stator core 31. FIG. 4 is a plan view of the electrical steel sheet 40 before forming the divided core piece forming portion 41. FIG. 5 is a plan view showing a molded steel plate 50 in which the divided core piece forming portion 41 to be the divided core piece 33 is formed. FIG. 6 is a diagram schematically showing pushback processing. FIG. 7 is a perspective view showing a molded steel plate laminate 60 in which a plurality of molded steel plates 50 are laminated in the thickness direction. FIG. 8 is a plan view showing the stator core laminate 70 obtained by cutting the molded steel plate laminate 60. FIG. 9 is a plan view showing a state in which the molded steel plate laminate 60 is cut along the cutting line X. FIG. 10 is a perspective view showing a state in which the stator core laminate 70 is divided into a plurality of divided cores 32.

First, a circular central hole 40a is punched in an electromagnetic steel plate which is a magnetic material. This step is the central hole punching step shown in FIG. 3 (step S1). The center of the central hole 40a coincides with the central axis P of the motor 1.

Next, a plurality of slots 40b are punched around the central hole 40a in order to form a plurality of tooth pieces 33b surrounding the central hole 40a. This step is the slot punching step shown in FIG. 3 (step S2).

The above-mentioned central hole punching step and slot punching step are performed by press working. Since the central hole punching step and the slot punching step are the same as the conventional stator core manufacturing method, detailed description thereof will be omitted.

FIG. 4 shows an electromagnetic steel sheet 40 (hereinafter referred to as a steel sheet) in which a central hole 40a and a slot 40b are formed as described above.

As shown in FIG. 4, the outer shape of the steel sheet 40 is punched into a predetermined polygonal shape, and a plurality of through holes 40c are punched on the outer peripheral side. The outer shape of the steel plate 40 and the through hole 40c may be punched at the same time as the above-mentioned central hole punching step or slot punching step, or before or after the central hole punching step and slot punching step, or their steps. You may go between.

Next, in the steel plate 40 in which the central hole 40a and the slot 40b are formed as described above, as shown in FIG. 5, a divided core piece forming portion 41 serving as the divided core piece 33 is provided on the outer peripheral side of the central hole 40a. Form multiple rings side by side. The split core piece forming portion 41 has a fan shape centered on the central axis P. The split core piece molding portion 41 has a split yoke piece molding portion 41a that becomes a split yoke piece 33a and a tooth piece 33b. In the step of molding the split core piece molding portion 41, the split yoke piece molding portion 41a is molded. Specifically, in the step of forming the split core piece forming portion 41, the outer side of the steel plate 40 from the tooth piece 33b with respect to the center of the central hole 40a is punched out in the shape of the split yoke piece 33a in the thickness direction. , So-called pushback processing is performed to return the punched portion to the original position. This step is the pushback step shown in FIG. 3 (step S3).

As shown in FIG. 6, the pushback processing includes a first tool W1 having a pair of upper and lower tools for sandwiching a part of the steel plate 40 in the thickness direction, and a pair of upper and lower tools for sandwiching a part of the steel plate 40 in the thickness direction. This is done using the second tool W2. The first tool W1 is movable with respect to the second tool W2 in the thickness direction of the steel plate 40. In the present embodiment, the first tool W1 has the same shape as the split yoke piece 33a.

As shown in FIG. 6A, the first tool W1 moves in one direction in the thickness direction of the steel plate 40 with respect to the second tool W2, so that the portion of the steel plate 40 sandwiched between the first tool W1 and the second tool. 2 Shearing is performed at the boundary with the portion sandwiched between the tools W2. The moving distance of the first tool W1 with respect to the second tool W2 may be a moving distance that separates the steel plate 40, or may be a moving distance that does not separate the steel plate 40.

After that, as shown in FIG. 6B, the first tool W1 is returned to the original position by moving the first tool W1 to the other side in the thickness direction of the steel plate 40 with respect to the second tool W2. As a result, at the boundary, the portion of the steel plate 40 sandwiched between the first tool W1 is fitted into the portion sandwiched between the second tool W2.

The split yoke piece forming portion 41a has an extruded portion 42 in which the pushback process as described above is performed, and a non-extruded portion 43 that is not extruded. As shown in FIG. 5, the extruded portions 42 and the non-extruded portions 43 are alternately located in the circumferential direction.

A dividing portion 44 is formed between the extruded portion 42 and the portion that is not extruded by the pushback process. That is, a divided portion 44 is formed by pushback processing at the boundary between the extruded portion 42 and the non-extruded portion 43 and the boundary between the extruded portion 42 and the outer peripheral side of the steel plate 40, respectively. In the dividing portion 44, the extruded portion 42 is held by friction with respect to the other portions.

Further, by pushback processing, two connecting portions 45 in which the divided portion 44 is not formed are formed in the extruded portion 42 on the radial outer side of the divided yoke piece forming portion 41a in the divided core piece forming portion 41. That is, the extruded portion 42 is a two-connection connecting the radial outside of the split yoke piece forming portion 41a in the split core piece forming portion 41 and the portion other than the divided core piece forming portion 41 in the molded steel plate 50 by a part thereof. It has a portion 45. The two connecting portions 45 are located radially outside the split yoke piece forming portion 41a in the extrusion portion 42, apart from each other in the circumferential direction.

In the present embodiment, the two connecting portions 45 are formed at positions on the radial outside of the split yoke piece forming portion 41a so as to sandwich the portion extending in the radial direction of the tooth piece 33b in the circumferential direction. That is, the two connecting portions 45 are pushed back to one end side and the other end side in the radial direction of the split core piece molding portion 41 and in the circumferential direction of the split core piece molding portion 41, respectively. It is formed. As a result, the divided core piece forming portion 41 can be stably connected by the connecting portion 45 to the portion other than the divided core piece forming portion 41 in the molded steel sheet 50. Therefore, it is possible to further prevent the split core piece forming portion 41 from falling off from the formed steel plate 50.

The dimension of the connecting portion 45 in the circumferential direction of the divided core piece molded portion 41 in the plan view of the molded steel plate 50 is larger than the thickness of the molded steel plate 50. This can prevent the connecting portion 45 from being easily cut. Therefore, it is possible to prevent the split core piece forming portion 41 from falling off from the formed steel plate 50. The thickness of the molded steel sheet 50 is the thickness of the unprocessed portion of the molded steel sheet 50.

By having the extruded portion 42 having the two connecting portions 45 as described above, it is possible to prevent the extruded portion 42 from falling off from the molded steel plate 50 even when vibration or an external force is applied to the extruded portion 42 or the tooth piece 33b.

As described above, the step of forming the molded steel sheet 50 in which a plurality of the divided core piece forming portions 41 to be the divided core piece 33 are arranged in an annular shape by the pushback process corresponds to the pushback process.

As described above, by forming the split yoke piece forming portion 41a by pushback processing, the split yoke piece forming portion 41a is not bent at the time of processing. This makes it possible to suppress the generation of residual stress and residual strain due to processing. Therefore, the dimensional accuracy of the split core piece 33, that is, the stator core 31 can be improved. Further, by suppressing the generation of residual stress and residual strain as described above, the turbulence of the magnetic flux flow in the split core piece 33 can be suppressed, so that the deterioration of the magnetic characteristics of the stator core 31 can be suppressed.

As described above, after the split yoke piece forming portion 41a is formed on the steel plate 40 by pushback processing, the caulking portion 33c is formed on the divided yoke piece forming portion 41a and the tooth piece 33b. The caulked portion 33c is obtained by forming a convex portion on the split yoke piece forming portion 41a and the tooth piece 33b so as to protrude in one direction in the thickness direction and have a concave portion on the surface on the other side in the thickness direction. The step of forming the crimped portion 33c is the crimped portion forming step shown in FIG. 3 (step S4).

After that, the molded steel sheets 50 on which the split yoke piece molded portions 41a are formed are laminated in the thickness direction, and the caulked portions 33c of the adjacent molded steel sheets 50 are crimped to form the molded steel sheet laminate 60 as shown in FIG. (Laminate) is obtained. This step is the laminating step shown in FIG. 3 (step S5).

Then, the molded steel plate laminate 60 is cut at the cutting position X (the position shown by the broken line in FIG. 7) on the outer peripheral side of the split yoke piece forming portion 41a by electric discharge machining or the like, as shown in FIG. A stator core laminate 70 is obtained. That is, as shown in FIG. 9, the molded steel plate 50 constituting the molded steel plate laminate 60 is cut at the cutting position X, and as shown in FIG. 9, the stator core steel plate 80 constituting the stator core laminate 70 and its diameter. It is separated from the steel plate balance 90 located on the outer side in the direction.

Here, as shown in FIGS. 7 and 9, the cutting position X is radially inside the split portion 44 located on the radial outside of the split yoke piece forming portion 41a. In this way, when the molded steel sheet laminate 60 is cut radially inside the split yoke piece forming portion 41a located on the radial outside of the split yoke piece forming portion 41a, as shown in FIG. 9, the split yoke piece forming portion 41a The portion 81 (hereinafter referred to as the stator core remaining portion) radially outside the cutting position X and radially inside the dividing portion 44 remains in the steel plate remaining portion 90. In the present embodiment, as described above, the extruded portion 42 of the split yoke piece forming portion 41a has a connecting portion 45 in which the dividing portion 44 is not provided on the radial outer side. Therefore, when the molded steel sheet laminate 60 is cut at the cutting position X as described above, it is possible to prevent the stator core remaining portion 81 from falling off from the steel plate remaining portion 90.

This step is the laminate processing step shown in FIG. 3 (step S6).

Even after the molded steel sheet laminated body 60 is cut at the cutting position X as described above, the divided portion 44 remains between the adjacent divided yoke piece forming portions 41a in the stator core laminated body 70.

As shown in FIG. 10, a dividing portion located between adjacent split yoke piece forming portions 41a is applied to the outer peripheral side of the stator core laminate 70 by applying a force of a component in the direction perpendicular to the lamination direction. The 44 is separated, and the stator core laminate 70 is divided into a plurality of divided cores 32. When the stator core laminated body 70 is divided into a plurality of divided cores 32, if the stator core laminated body 70 can be divided into a plurality of divided cores 32, which one is used with respect to the stator core laminated body 70? You may apply such force.

As in the present embodiment, the stator core laminated body 70 is formed by applying a force of a component in the direction perpendicular to the laminating direction of the molded steel plate 50 to the outer peripheral side of the stator core laminated body 70. The stator core laminate 70 can be easily divided into a plurality of divided cores 32 without peeling of the steel plate.

As described above, the stator core laminated body 70 is divided into a plurality of divided cores 32 by applying the force of the component in the direction perpendicular to the laminating direction of the molded steel plate 50 to the outer peripheral side of the stator core laminated body 70. The process to be performed corresponds to the division process (step S7 in FIG. 3).

According to the configuration of the present embodiment, the split core piece molded portion 41 formed by pushback processing by the connecting portion 45 connecting the radial outside of the split core piece molded portion 41 and the steel plate remaining portion 90 of the molded steel sheet 50 is a molded steel plate. It is possible to prevent the product from falling out of 50. Therefore, the molded steel plate 50 on which the divided core piece molded portion 41 is formed can be easily laminated in the thickness direction. Therefore, the productivity of the stator core 31 can be improved.

Further, when the molded steel plate laminate 60 is cut at the cutting position X by the connecting portion 45 connecting the radial outside of the split core piece forming portion 41 and the steel plate remaining portion 90 of the molded steel plate 50, the stator core remaining portion 81 However, it can also be prevented from falling off from the steel plate remaining portion 90.

(Other Embodiments) Although the embodiments of the present invention have been described above, the above-described embodiments are merely examples for carrying out the present invention. Therefore, the embodiment is not limited to the above-described embodiment, and the above-described embodiment can be appropriately modified and implemented within a range that does not deviate from the gist thereof.

In the above embodiment, the extruded portion 42 of the split yoke piece forming portion 41a has two connecting portions 45 on the outer side in the radial direction in which the divided portion 44 is not formed. However, the extruded portion may have three or more connecting portions or may have only one connecting portion. By having a plurality of connecting portions in the extruded portion, it is possible to further prevent the split core piece molded portion from falling off from the steel sheet.

In the above embodiment, the two connecting portions 45 are formed at positions on the radial outside of the split yoke piece forming portion 41a so as to sandwich the portion extending in the radial direction of the tooth piece 33b in the circumferential direction. However, as shown in FIG. 11, the connecting portion 145 may be located radially outward with respect to the tooth piece 33b on the radial outside of the split yoke piece forming portion 141a. When the connecting portion is formed by the pushback step, the connecting portion between the connecting portion and the split core piece molded portion may be distorted. On the other hand, as described above, by providing the connecting portion 145 at a position radially outward with respect to the tooth piece 33b in the radial outside of the split core piece molding portion 141, the magnetic flux in the stator core 31 The connecting portion 145 can be formed at a position that does not easily affect. Therefore, the influence of the connecting portion 145 on the magnetic characteristics of the stator 3 can be suppressed. In FIG. 11, reference numeral 150 is a molded steel sheet, reference numeral 141a is a split yoke forming portion, and reference numeral 142 is an extrusion portion.

In the above embodiment, the stator core laminate 70 is obtained by cutting the molded steel plate laminate 60 at the cutting position X in the laminate processing step. However, the steel plate constituting the stator core laminate may be formed in the pushback step. This makes it possible to omit the laminate processing step in the method for manufacturing the stator core.

In the above embodiment, the motor is a so-called permanent magnet motor. In a permanent magnet motor, the rotor has a magnet. However, the motor 1 may be a motor without a magnet, such as an inducer, a reluctance motor, a switch reluctance motor, or a winding field type motor.

INDUSTRIAL APPLICABILITY The present invention is applicable to a method for manufacturing a stator core in which a plurality of plate-shaped divided core pieces are laminated and the stator core is arranged in an annular shape about a central axis.

1 Motor 2 Rotor 3 Stator 31 Stator core 31a York 31b Teeth 32 Divided core 32a Divided yoke part 33 Divided core piece 33a Divided yoke piece 33b Teeth piece 33c Caulking part 40 Electromagnetic steel plate (steel plate) 40a Central hole 40b Slot 40c Penetration Hole 41 Divided core piece molded part 41a, 141a Divided yoke piece molded part 42, 142 Extruded part 43 Non-extruded part 44 Divided part 45, 145 Connecting part 50, 150 Molded steel plate 60 Molded steel plate laminate (laminator) 70 Stator core Laminated body 80 Stator core steel plate 81 Stator core balance 90 Steel plate balance P Central axis W1 First tool W2 Second tool X Cutting position

Claims (6)

A split core in which a plurality of plate-shaped split core pieces are laminated is a method for manufacturing a stator core in which a stator core is arranged in an annular shape around a central axis.
After punching a part of the steel sheet in the thickness direction, the punched part is returned to the original position of the steel sheet by pushback processing.
On the steel plate
In a plan view, a fan-shaped split core piece molded portion centered on the central axis is formed by arranging a plurality of split core piece molded portions in an annular shape, and the radial outside of the split core piece molded portion and the steel plate. A connecting portion is formed to connect the portions other than the divided core piece forming portion with those portions.
The split core piece molding portion has a split yoke piece molding portion that becomes a split yoke piece and a tooth piece, and the split yoke piece molding portion includes an extruded portion in which pushback processing is performed and a non-extruded portion that is not extruded. Have,
A divided portion is formed by pushback processing at the boundary between the extruded portion and the non-extruded portion and the boundary between the extruded portion and the outer peripheral side of the steel sheet, respectively.
A stator core manufacturing method having a pushback step, in which the connecting portion is located radially outside the split yoke piece molding portion in the extrusion portion . In the stator core manufacturing method according to claim 1,
The pushback step is a stator core manufacturing method in which a plurality of connecting portions are formed on the radial outer side of the divided core piece molded portion. In the stator core manufacturing method according to claim 1 or 2.
A laminating step of obtaining a columnar laminated body by laminating the steel plate on which the divided core piece molded portion and the connecting portion are formed by the pushback step in the thickness direction.
A laminate processing step of forming a stator core having the plurality of split cores by cutting the laminate radially inside the connecting portion.
Further, a stator core manufacturing method. In the stator core manufacturing method according to any one of claims 1 to 3,
A stator core manufacturing method in which the dimension of the connecting portion in the circumferential direction of the split core piece molded portion in a plan view is larger than the thickness of the steel plate. In the stator core manufacturing method according to any one of claims 1 to 4.
In the pushback step, the stator is formed by molding the connecting portion at a position radially outside the portion of the divided core piece molded portion in the radial direction with respect to the tooth piece constituting the teeth of the stator core. Core manufacturing method. In the stator core manufacturing method according to claim 2,
In the pushback step, the connecting portion is formed on one end side and the other end side in the circumferential direction of the divided core piece forming portion on the radial side of the divided core piece forming portion. Stator core manufacturing method.

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