JP5462675B2 - Manufacturing method of laminated iron core - Google Patents

Description

The present invention relates to a method for manufacturing a laminated core including a stator core used in, for example, a stepping motor, which can be plated from a plate-like material with a high yield and is excellent in productivity.

Conventionally, a laminated iron core for a stepping motor has a very small air gap between the rotor core and the stator core. It may be pulled out twice without falling down. In addition, the mold may be damaged due to the catching of scrap. Also, if the pole teeth (magnetic pole piece) cannot be punched in the desired multiple shapes, the rotor core piece and the stator core piece must be punched with separate dies, which greatly reduces the material yield. There was a problem of cost.

As a conventional technique for solving the above-described problem, for example, as described in Patent Document 1, at least one surface of a rotor core piece and a stator core piece is pressed in the plate thickness direction by a coining process. There has been proposed a flat and thin-walled portion that allows a rotor core piece and a stator core piece to be shared with a single mold.

And the technique of patent document 1 forms a small tooth simultaneously with the outer periphery extraction (process D of FIG. 1) of a rotor core piece, and the inner periphery extraction (process H of FIG. 1) of a stator core piece. However, at this time, in order to prevent the die from being damaged due to dregling, the entire circumference was removed by one punching so that the scrap was connected in a ring shape.

Japanese Patent No. 2955804

However, in recent years, when all of the small teeth are formed by one punching (spline punching) simultaneously with the outer periphery of the rotor core piece and the inner periphery of the stator core piece as described above, the sagging of the outer periphery of the small teeth is large. As a result, it was found that the torque of the motor was reduced by the sagging of the small teeth.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and at the time of forming the small teeth of the rotor core piece and the stator core piece, it is possible to improve the torque of the motor by minimizing the sagging of the small teeth by punching. An object of the present invention is to provide a method for producing a laminated core that can be manufactured.

The manufacturing method of the laminated core according to the present invention that meets the above-mentioned object is as follows: 1) A rotor core piece having first small teeth on the outer periphery is punched from a thin sheet material; And is formed by punching a stator core piece having an annular yoke piece portion and a magnetic pole piece portion having a second small tooth on the inner periphery integrally connected to the inner side in the radial direction of the yoke piece portion In the method of manufacturing a laminated core in which the rotor core piece and the stator core piece are laminated in a die,
The rotor core piece has a first slit formed to form a radially inner end portion of the first small teeth, and then performs an outer peripheral punch to form a radially outer end portion of the first small teeth. ,
The stator core piece is formed by punching a spare slot smaller than the finishing slot forming the adjacent magnetic pole piece portion, and then performing coining on a part or all of the magnetic pole piece portion so that the magnetic pole piece portion is radially inward. A second slit punching to form the radially outer end of the second small tooth, with the finishing slot being punched out, leaving an annular piece formed radially inward, and After the third slit is formed to form the adjacent magnetic pole pieces, the inner periphery is formed to form the radially inner end of the second small teeth.

In the method for manufacturing a laminated core according to the present invention, the second slit and the third slit are formed after the coining process, and the first slit is formed before the coining process. A method for producing a laminated iron core, wherein the laminated core is formed so that at least a part of the region overlaps.

In the method for manufacturing a laminated core according to the present invention, it is preferable to perform a correction process for correcting the bending habit caused by the coining process before or after forming the finishing slot. In general, when coining is performed, warpage occurs from the part to the inner magnetic pole shaft piece and the magnetic pole tooth piece connected thereto, so correction such as pressing the warp (bending wrinkle) with a press or holding it with a stripper. Process and eliminate bending habits. In particular, when the adjacent magnetic pole tooth pieces are connected, the radially inner side of the stator core piece is lifted (or lowered), and this straightening process causes plastic deformation of the material to flatten it. To do.

In the method for manufacturing a laminated core of the present invention, the thin strip material forms a first pilot hole in an initial step, and the rotor core piece is punched and the spare slot is formed on the basis of the first pilot hole. The punching, the coining, and the finishing slot are formed, the second pilot hole is formed at the same time as or after the finishing slot is formed, and the subsequent press processing is performed based on the second pilot hole. It is good. This makes it possible to manufacture a more accurate stator core piece.

In this case, it is preferable that the second pilot hole has a larger diameter than the first pilot hole and is formed by being re-extracted on the first pilot hole.
Note that the second pilot hole may be formed at a position different from that of the first pilot hole.

In this method of manufacturing a laminated core, the stator core pieces arranged above and below are laminated via a caulking portion, and the caulking portion is preferably formed with reference to the second pilot hole.

In the method of manufacturing a laminated core according to the present invention, the rotor core piece is first slitted to form the radially inner end of the first small tooth, and then the radially outer end of the first small tooth. The stator core piece is formed with a second slit remover that forms the radially outer end of the second small tooth while leaving the annular piece formed radially inward. After performing the third slit forming to form the adjacent magnetic pole piece portion, by performing the inner peripheral punching to form the radially inner end portion of the second small teeth, the punching load becomes smaller than the spline punching, The sagging of the formed small teeth can be made smaller than that of spline removal, and as a result, the torque of the motor can be improved. In addition, the life of the blade that punches the outer periphery of the rotor core piece and the inner periphery of the stator core piece can be extended, and the magnetic pole piece portion of the stator core piece can be connected to the finish slot that forms the adjacent magnetic pole piece portion. After punching out a small spare slot, a part or all of the pole piece is coined to extend the pole piece inward in the radial direction, and then the finish slot is punched and the pole tooth piece is formed. As it is formed, the coining portion of the magnetic pole piece can be stably stretched, and the entire slot including the magnetic pole piece deformed by coining can be formed according to dimensions by punching and forming the finish slot after coining, The finishing accuracy of the stator core piece is improved.

Further, the second slit and the third slit extraction region formed after the coining process are formed so that at least a portion thereof overlaps with the first slit extraction region formed before the coining process. By this method, the small teeth of both the rotor core and the stator core can be formed by slitting. This is realized by the presence of coining.

In addition, the method for manufacturing a laminated iron core according to the present invention includes a magnetic pole piece generated by coining by performing a straightening process to correct a bending crease (warp) generated by the coining process before or after forming the finish slot. It is possible to eliminate the deformation of the portion and the magnetic pole tooth piece that follows, and to flatten the stator core piece.

In this method of manufacturing a laminated iron core, the thin strip material forms a first pilot hole in an initial step, and the rotor core piece is punched, a spare slot is punched, and coining is performed based on the first pilot hole. , And forming the finishing slot, and correcting the deformation of the stator core piece caused by coining again by performing subsequent pressing with reference to the second pilot hole at the same time as or after forming the finishing slot, More accurate stator core pieces can be manufactured.

Here, the diameter of the second pilot hole is larger than that of the first pilot hole. By forming the second pilot hole on the first pilot hole, the plate cutting efficiency for forming the stator core piece from the thin strip material is improved. In addition, it is possible to effectively use the position where the first pilot hole is formed.

Further, the stator core pieces arranged on the upper and lower sides are laminated via the caulking part, and the caulking part is formed with reference to the formation position of the magnetic pole piece part by forming the caulking part with reference to the second pilot hole. The formation position of can be determined.

It is a perspective view of the stator core and rotor core manufactured using the manufacturing method of the laminated core which concerns on one embodiment of this invention. (A) is a perspective view of a stator core piece used for the stator core, and (B) is an AA arrow cross-sectional view. It is process drawing which shows the manufacturing method of the laminated core which concerns on one embodiment of this invention. It is process drawing which shows the manufacturing method of the laminated core which concerns on one embodiment of this invention. It is process drawing which shows the manufacturing method of the laminated core which concerns on one embodiment of this invention. It is explanatory drawing of the manufacturing method of the laminated core which concerns on one embodiment of this invention.

FIG. 1 shows a stator core 10 and a rotor core 11 manufactured by a method for manufacturing a laminated core according to an embodiment of the present invention. These are used in a stepping motor, and the stator core 10 is viewed in plan view. An annular yoke portion 12 and a plurality of magnetic pole portions 13 provided inside the yoke portion 12 are provided. The stator core 10 and the rotor core 11 are each configured by caulking and stacking a stator core piece 14 and a rotor core piece 15 made of magnetic steel plates. K1 and K2 are small teeth, 16 and 17 are caulking portions, 17a is a shaft hole, and the caulking portions 16 and 17 are well-known half-cut caulking or V-shaped caulking.

As shown in FIGS. 2 (A) and 2 (B), the stator core piece 14 has an annular yoke piece 18 and a plurality of pieces (in this embodiment, integrally formed radially inward of the yoke piece 18). 8) of the magnetic pole piece 19. The magnetic pole piece portion 19 has a magnetic pole shaft piece portion 20 connected to the inside of the yoke piece portion 18 and a magnetic pole tooth piece portion 21 connected to the inner side of the magnetic pole shaft piece portion 20. A plurality of small teeth 22 are formed on the inner side in the radial direction. In this embodiment, a groove 24 is formed in a part (or all) of each magnetic pole piece 20 by a coining process having a constant width in the radial direction and continuing in the circumferential direction, and a thin portion (thin portion) in this portion. 25 is formed.

As shown in FIGS. 3-5, the manufacturing method of the laminated iron core which concerns on one embodiment of this invention is a mold apparatus which has the thin strip material 27 which consists of a magnetic steel plate, and has the station of (A)-(K). It is manufactured through the steps (A) to (K) using (sequential feeding mold device). These will be described in detail below.

In the station (A) (that is, the step (A), the same applies hereinafter), the first pilot hole 28 that is paired with the thin strip member 27, and the radially inner end of the first small tooth K1 in the rotor core piece 15 are provided. The first slit S1 forming the part is punched out.

In the station (B), the thin strip member 27 is positioned by the first pilot hole 28, and the caulking portion 17 and the shaft hole 17a of the rotor core piece 15 are punched and formed. The caulking portion 17 is a caulking through-hole in the rotor core piece 15 positioned at the lowermost portion, but the caulking portion 17 is convex downward in the rotor core piece 15 laminated thereafter. The station for forming the caulking through hole can be provided as a separate station before the station (B). The rotor core piece 15 and the stator core piece 14 are formed on the same axis.

In the station (C), the outer periphery forming the radially outer end of the first small tooth K1 of the rotor core piece 15 is removed and removed. The removed rotor core pieces 15 are stacked in a mold to form the rotor core 11.
In the station (D), a preliminary slot 29 that forms the approximate shape of each magnetic pole shaft piece 20 and magnetic pole tooth piece 21 of the stator core piece 14 in the circumferential direction is formed. In this embodiment, since there are eight (a plurality) of pole piece portions 19, eight spare slots 29 are formed simultaneously. The spare slot 29 is smaller than the finishing slot 30 described below, and has a finishing allowance of a little (for example, 0.5 to 10 times the plate thickness).

In the station (E), with reference to the first pilot hole 28, a part of the magnetic pole piece 20 formed by the spare slot 29 is pressed by the ring-shaped punch P to each magnetic pole piece 20 Coining evenly. At this time, since the stripper of the mold apparatus presses the radially outer region from the coining portion (groove 24) and opens the radially inner side from the coining portion, the surplus due to coining escapes radially inward. By this coining process, the magnetic pole piece 20 is extended radially inward by 20 to 80% of the plate thickness.

The groove 24 formed by the coining process (that is, corresponding to the thin portion 25) is preferably located on the innermost side of the magnetic pole piece 20, thereby minimizing the distortion of the extended magnetic pole piece 21. can do. The volume of the portion extended by coining (plate thickness t × width of magnetic pole piece 20 × elongation allowance) is approximately the volume of groove 24 (depth of groove 24 × width of magnetic pole piece 20 × groove 24). In the radial direction a). If the groove 24 is too deep, the magnetic characteristics of the magnetic pole piece 20 will deteriorate, so the depth of the groove 24 is 0.1 to 0.5 times the plate thickness (more preferably 0.1 to 0.4 times). ) Is preferable (see FIG. 2B).

In this embodiment, since the adjacent magnetic pole tooth pieces 21 are connected in the circumferential direction, if the magnetic pole shaft piece 20 is extended inward in the radial direction, bending bend due to coining occurs, and the magnetic pole tooth pieces 21 rises. Therefore, press work is performed to suppress this lifting at the next station. This pressing may be performed by pressing the thin strip 27 with a stripper used at the next station (F), or bending between the stations (E) and (F) (or after the station (F)). A correction processing station for correcting the above may be provided.

In the station (F), the finishing slot 30 for forming the final shape of the magnetic pole shaft piece 20 and the shape of the magnetic pole tooth piece 21 in the circumferential direction is formed with reference to the first pilot hole 28 formed in the initial step. The second pilot hole 32 is formed by expanding the diameter of the first pilot hole 28 on the downstream side in the advancing direction of the thin strip 27 whose punching has been corrected (ie, forming the pilot hole again). At this time, the finishing slot 30 is punched so as to include the entire circumference of the spare slot 29 or the entire circumference except a part thereof. The second pilot hole 32 can also be formed at a position different from the first pilot hole 28. Alternatively, the second pilot hole 32 can be formed after the finish slot 30 is formed.

In the station (G), the contours of the second small teeth K2 formed on the radially inner side of the magnetic pole tooth piece portion 21 and the adjacent magnetic pole tooth piece portions 21 are formed on the basis of the second pilot holes 32, respectively. The second and third slits S2 and S3 are punched.

The second and third slits S2 and S3 will be described in detail with reference to FIG.
In FIG. 6, the slits S2 and S3 are indicated by hatching. A contour line 37 formed by the preliminary slot 29 is indicated by a dotted line, and a contour line 38 of the preliminary slot 29 extended in the radial direction by coining is indicated by a dotted line. An outline 39 of the first slit S1 that forms the small teeth K1 of the rotor core piece 15 before the coining process is indicated by a dotted line, and a line of the rotor core piece 15 after the coining process is indicated by a solid line 40. Here, the extraction region of the second slit S2 and the third slit S3 formed after the coining process is formed so as to partially overlap the extraction region of the first slit S1 formed before the coining process. Is done. Thus, the second slit S2 and the third slit S3 can be stamped and formed by performing coining after the first slit S1 is formed and extending the magnetic pole piece 20 inward in the radial direction. It becomes.
Since the third slit S3 is formed so as to be mismatched so as to partially include the region where the finishing slot 30 is formed, the third slit S3 is slightly recessed in the second small teeth K2 located at both ends of the magnetic pole tooth piece portion 21. M is formed. As a result, it is possible to prevent uncut portions and burrs from being generated at portions where punching overlaps.

In the station (H), the caulking portion 16 is formed with reference to the second pilot hole 32. In the stator core piece 14 positioned at the lowermost portion, the caulking portion 16 is a caulking through hole, but in the stator core piece 14 laminated thereafter, the caulking portion 16 is convex downward.
The station for forming the caulking through hole can be provided as a separate station before the station (H). In the stator core piece 14 shown in FIGS. 1 and 2, the caulking portions 16 are alternately provided on the radially outer side and the inner side of the magnetic pole piece portion 19, but the station (H in FIG.
) As will be described later, it is also possible to provide the magnetic pole pieces 19 on the inner side in the radial direction and on the yoke piece 18 at a pitch of two magnetic poles. In order to further improve the magnetic characteristics, it may be formed only on the yoke piece 18.

Subsequently, in the station (I), circular extraction with a radius r that forms the inner contour of the second small tooth K2 is performed. The outline of the second small teeth K2 formed thereby is indicated by a solid line 41. As a result, as shown in FIG. 6, the cutting bar 44 composed of the outer shape line having the radius r and the annular piece indicated by the solid line 40 is removed. Molding of the magnetic pole tooth piece portion 21 forming the small teeth 22 is completed at the stations (F), (G), and (I).

In the present embodiment, since the groove and the inner shape of the second small tooth K2 are punched out in separate steps, the punch bar (cut barb) 44 has an annular shape and is smoothly pulled out without being caught. Compared with spline punching, the punching load applied to the punching punch is small, so that wear and breakage of the punch can be reduced. The minimum radial width c of the cutting bar 44 is 0.1 mm (more preferably 0.2 mm) or more. The reason is that, when the radial minimum width is 0.1 mm or less, the rigidity of the cutting bar 44 is lowered and the ring is not maintained in a ring state, and the die is damaged.

At the next station (J), the outer shape of the stator core piece 14 is removed and caulked and stacked in a die. In the station (K), a thin strip (skeleton) from which the stator core piece 14 and the rotor core piece 15 are removed is shown.

The present invention is not limited to the above-described embodiment, and the present invention can be applied even if the dimensions, the number of magnetic poles, and the shape of the pole teeth are changed without changing the gist of the present invention. .
Furthermore, the present invention is also applied to a laminated iron core that uses a normal stator core piece that does not form small teeth inside the magnetic pole tooth piece portion.

10: Stator core, 11: Rotor core, 12: Yoke part, 13: Magnetic pole part, 14: Stator core piece, 15: Rotor core piece, 16, 17: Caulking part, 17a: Shaft hole, 18: York piece part, 19: magnetic pole piece part, 20: magnetic pole piece part, 21: magnetic pole tooth piece part, 24: groove, 25: thin part, 27: thin strip material, 28: first pilot hole, 29: spare Slot: 30: Finished slot, 32: Second pilot hole, 37: Outline of spare slot, 38: Outline of extended spare slot, 39: Outline of first slit before coining, 40: Coining Rear rotor core punching line, 41: inner diameter circle of small teeth, 44: cutting punch (punching punch), P: coining punch, K1: first small tooth, K2: second small tooth, S1: 1st slit, S2: 2nd slit, S3: 3rd Lit, M: recess

Claims (6)

From the thin strip material, 1) a rotor core piece having first small teeth on the outer periphery is formed by punching, and 2) an annular yoke piece portion and the yoke piece are arranged in alignment with the rotor core piece. A stator core piece that is integrally connected to the inner side in the radial direction of the part and includes a magnetic pole piece portion having second small teeth on the inner periphery, and the rotor core piece and the stator core piece are die-formed. In the manufacturing method of the laminated iron core laminated in the inside,
The rotor core piece has a first slit formed to form a radially inner end portion of the first small teeth, and then performs an outer peripheral punch to form a radially outer end portion of the first small teeth. The stator core piece is formed by punching a spare slot smaller than a finish slot forming the adjacent magnetic pole piece part, and then performing coining on a part or all of the magnetic pole piece part to radially arrange the magnetic pole piece part. A second slit punch that extends inward and then punches the finish slot to form a radially outer end of the second small tooth, leaving an annular piece formed radially inward. And a third slit forming the adjacent magnetic pole piece, and then an inner peripheral forming the radially inner end of the second small tooth is performed. 2. The method of manufacturing a laminated core according to claim 1, wherein the second slit formed after the coining and the third slit are formed in the first slit formed before the coining. 3. A method for producing a laminated iron core, characterized in that it is formed so that at least a part thereof overlaps with a blank region. 3. The method for manufacturing a laminated core according to claim 1, wherein a straightening process is performed to correct a bend caused by the coining process before or after the finishing slot is formed. . The method for manufacturing a laminated core according to any one of claims 1 to 3, wherein the thin strip material forms a first pilot hole in an initial step, and the rotor core is based on the first pilot hole. Punching a piece, punching the spare slot, coining, and forming the finishing slot, forming a second pilot hole at the same time as or after forming the finishing slot, and forming the second pilot hole A method for manufacturing a laminated core, characterized in that a subsequent press work is performed as a reference. 5. The method of manufacturing a laminated core according to claim 4, wherein the second pilot hole has a diameter larger than that of the first pilot hole and is formed by being re-extracted on the first pilot hole. Manufacturing method of iron core. 6. The method for manufacturing a laminated core according to claim 4 or 5, wherein the stator core pieces arranged vertically are laminated via a caulking portion, and the caulking portion is formed with reference to the second pilot hole. A method for producing a laminated iron core characterized by:

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