Manufacturing method of stator core for coreless motor

Abstract

To provide a manufacturing method of a stator core for a coreless motor which can improve utilization rate of a belt-like steel plate.SOLUTION: A manufacturing method of a stator core 1 for a coreless motor according to an embodiment comprises steps of: punching a belt-like steel plate 8 to form split core pieces 4; and laminating the split core pieces 4 as combining them in a circumferential direction to form the stator core 1. Then, in the step of forming the split core pieces 4, the belt-like steel plate 8 is punched so that the split cores 4 become two rows in a width direction of the belt-like steel plate 8, an outer peripheral side of the split core pieces 4 in each row is located outside the width direction of the belt-like steel plate 8, projections 5 of the split core pieces 4 are located on an inner peripheral side of the split core pieces 4 in the other row, and an end formed with recesses 6 of the split core pieces 4 faces an end formed with the recesses 6 of the split core pieces 4 in the other row to form the split core pieces 4.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] Embodiments of the present invention relate to a method for manufacturing a stator core for a coreless motor.

Background Art

[0002] Conventionally, as described in Patent Document 1 for example, a rotor core of a rotating electrical machine is formed by punching a strip steel sheet, so that a core material for an annular stator core and a core material for a rotor core are continuously formed on the inner peripheral side thereof.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, a coreless motor that does not use a rotor core may be used along with the weight reduction and multi-polarization of rotating electrical machines. In that case, when the stator core is manufactured by a conventional manufacturing method, the inner peripheral portion after punching the core material for the stator core is discarded, resulting in a problem of low utilization rate of the strip steel sheet.

[0005] Therefore, a method for manufacturing a stator core for a coreless motor that can improve the utilization rate of a strip steel sheet is provided.

Means for Solving the Problems

[0006] The method for manufacturing a stator core for a coreless motor according to an embodiment includes a step of punching a strip steel plate to form divided core pieces, and a step of laminating the divided core pieces while combining them in the circumferential direction to form a stator core. Each of the divided core pieces has an arc shape that is equally divided in the circumferential direction of the stator core, has a convex portion that protrudes outward from one end in the circumferential direction, and has a concave portion that is recessed from the other end and is combined with the convex portion of another adjacent divided core piece. In the step of forming the divided core pieces, the divided core pieces are arranged in two rows in the width direction of the strip steel plate, the outer circumferential side of each row of divided core pieces is located on the outer side in the width direction of the strip steel plate, the convex portion of the divided core piece is located on the inner circumferential side of the divided core piece in the other row, and the strip steel plate is punched so that the end where the concave portion of the divided core piece is formed faces the end where the concave portion of the divided core piece in the other row is formed, thereby forming the divided core pieces.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0008] Hereinafter, embodiments will be described with reference to the drawings. As shown in FIG. 1, the stator core 1 for a coreless motor is formed as an annular laminate as a whole by laminating thin plate-shaped core materials 2, and a plurality of slots 3 for mounting a coil (not shown) are provided on the inner peripheral side thereof. Note that the shape of the stator core 1, the shape or number of the slots 3 shown in FIG. 1 are merely examples and are not limited thereto. Hereinafter, the center of the annular stator core 1 is referred to as a center point (P), and the direction around the center point (P) is referred to as the circumferential direction.

[0009] In the case of this embodiment, the core material 2 is formed by combining divided core pieces 4 having a shape divided into three equal parts in the circumferential direction of the stator core 1. As shown in FIG. 2, this divided core piece 4 has a generally arc-shaped outer shape in which the angles formed by both ends in the circumferential direction and the center point are 120°. Also, the dividing position is between adjacent slots 3.

[0010] Further, the divided core piece 4 has a plurality of slots 3 formed on the inner peripheral side, and a convex portion 5 protruding outward from the end is formed at one end in the circumferential direction on the right side in the drawing, and at the other end on the left side in the drawing, a concave portion 6 that is recessed from the end and is combined with the convex portion 5 of the other divided core piece 4 arranged adjacent thereto is formed. Note that the shapes and numbers of the convex portion 5 and the concave portion 6 are merely examples and are not limited thereto, but both are formed at positions inside the outer periphery of the divided core piece 4.

[0011] Further, the divided core piece 4 has a groove portion 7 formed at the center in the circumferential direction on the outer peripheral side for fixing the laminated core material 2 by welding or a fastening metal. Hereinafter, a virtual line passing through the center point (P) and the center of the groove portion 7 is conveniently referred to as the center line (CL1) of the divided core piece 4. At this time, since the groove portion 7 is formed to be recessed from the outer peripheral side to the inner side, the width (W1) from the inner peripheral side to the outer peripheral side of the divided core piece 4 in the direction along the center line (CL1) is slightly shorter than the width (W0) to the outer peripheral side in the case where there is no groove portion 7 indicated by the broken line. Note that the size and shape of the groove portion 7 shown in FIG. 2 are merely examples and are not limited thereto.

[0012] Such a split core piece 4 is formed by the procedure shown in part of the manufacturing process in FIG. 3. Specifically, the split core piece 4 is formed by punching a strip steel plate 8 (see FIG. 4) (S1). By the way, when forming the annular stator core 1 as in the prior art, there is a problem that the inner peripheral side portion thereof is discarded and the utilization rate of the strip steel plate 8 becomes low. Also, in actual manufacturing, the manufacturing efficiency of the split core piece 4 is also important.

[0013] Therefore, in the present embodiment, as shown in FIG. 4, there are two rows, namely row A and row B, in the width direction of the strip steel plate 8. The outer peripheral sides of the split core pieces 4 in each row are located on the outer side in the width direction of the strip steel plate 8. The convex portions 5 of the split core pieces 4 are located on the inner peripheral side of the split core pieces 4 in the other row as shown by the broken line region (R1), and the ends where the concave portions 6 of the split core pieces 4 are formed face the ends where the concave portions 6 of the split core pieces 4 in the other row are formed. The split core pieces 4 are formed by punching the strip steel plate 8. In FIGS. 4 and 5, for easy understanding of the explanation, the portions that are punched to form the split core pieces 4 are marked with reference numerals.

[0014] At this time, as shown in the enlarged view in FIG. 5, the positions of the tips of the split core pieces 4 in the feeding direction of the split core pieces 4 are shifted in each row, and the inner peripheral side ends of the split core pieces 4 are formed in a staggered arrangement that exceeds the center line (CL2) of the strip steel plate 8 in the width direction toward the other row side.

[0015] When forming such split core pieces 4, since the inner peripheral side thereof becomes a non - utilized part, if punched in one row, the amount of discarded parts increases. On the other hand, by adopting a mode in which the split core pieces 4 are in two rows and the ends of the split core pieces 4 in the other row are arranged at the inner peripheral side parts that are not used for forming the split core pieces 4 in one row, it is possible to improve the utilization rate of the strip steel plate 8 and also possible to shorten the width of the required strip steel plate 8.

[0016] Further, each divided core piece 4 is formed in such a state that the groove portion 7 is located on the end side in the width direction of the strip steel plate 8 in both the A column and the B column. In the case of the present embodiment, each divided core piece 4 is punched out in a state where the groove portion 7 is located on the outermost side in the width direction of the strip steel plate 8. Due to the formation of the groove portion 7, the width (W1) of the divided core piece 4 is shorter than the width (W0) in the state without the groove portion 7.

[0017] Therefore, the required width (W2) of the strip steel plate 8 can also be made smaller compared to the case without the groove portion 7. Also, the portion outside the outer edge of the divided core piece 4, that is, the portion between the divided core pieces 4 in the same column in FIG. 5, is a portion that has to be discarded after punching. Therefore, if the width of the strip steel plate 8 can be made smaller, the discarded portion can also be reduced.

[0018] Further, each divided core piece 4 is in a state where the center line (CL1) is inclined with respect to the width direction of the strip steel plate 8 whose vertical direction in the drawing, and the positions of the ends of the adjacent divided core pieces 4 in the same column overlap at least in the feeding direction of the strip steel plate 8. It is formed by punching the strip steel plate 8 in a manner. This is possible because the convex portion 5 and the concave portion 6 are formed at positions inside the outer periphery of the divided core piece 4.

[0019] More specifically, among the divided core pieces 4 punched out adjacent to each other, the position (XA) of the rear end of the divided core piece 4A located in the front in the feeding direction overlaps the position (XB) of the front end of the divided core piece 4B located in the rear in the feeding direction, or each divided core piece 4 is formed in a state where the position (XA) of the rear end is behind the position (XB) of the front end.

[0020] As a result, the length in the feeding direction required to form one split core piece 4 is shortened, so that it is possible to greatly contribute to reducing the amount of the strip steel 8 used when forming a large number of split core pieces 4. When forming the split core pieces 4 in such a staggered arrangement, they may be punched out by one press machine. Although not shown in the drawings, for example, the press machine for column A and the press machine for column B may be arranged in series, or the strip steel 8 punched out in one column may be wound into a coil shape and then passed through the press machine again to punch out the other column, thereby forming them.

[0021] After forming the split core pieces 4, as shown in FIG. 3, the split core pieces 4 are laminated while being combined in the circumferential direction (S2). At this time, each split core piece 4 is arranged by combining the convex portion 5 and the concave portion 6 adjacent to each other in the circumferential direction while aligning the inner peripheral side with the outer peripheral surface of the cylindrical portion using a jig or the like having a cylindrical portion (not shown), thereby forming a single core material 2. Then, the next split core piece 4 is arranged while being combined on the core material 2, and the core materials 2 are laminated. After that, the laminated core materials 2 are fixed by welding, fastening, or the like to a predetermined height (S3), thereby manufacturing the stator core 1.

[0022] According to the manufacturing method described above, the following effects can be obtained. The manufacturing method of the stator core 1 for the coreless motor includes a step of punching out the strip steel 8 to form the split core pieces 4, and a step of laminating the split core pieces 4 while combining them in the circumferential direction to form the stator core 1. In the step of forming the split core pieces 4, the split core pieces 4 are arranged in two rows in the width direction of the strip steel 8, the outer peripheral sides of the split core pieces 4 in each row are located on the outer side in the width direction of the strip steel 8, the convex portions 5 of the split core pieces 4 are located on the inner peripheral side of the split core pieces 4 in the other row, and the strip steel 8 is punched out so that the ends where the concave portions 6 of the split core pieces 4 are formed face the ends where the concave portions 6 of the split core pieces 4 in the other row are formed, thereby forming the split core pieces 4.

[0023] As a result, it becomes possible to form the split core pieces 4 with the ends of the split core pieces 4 of the other row arranged at the inner peripheral side portions not used for forming the split core pieces 4 of one row, and the utilization rate of the strip steel plate 8 can be improved. Therefore, the utilization rate of the strip steel plate 8 can be improved.

[0024] Further, by providing the convex portions 5 and the concave portions 6, it is possible to ensure the concentricity and the roundness when the split core pieces 4 are combined. Further, since each split core piece 4 is formed in a staggered arrangement in two rows, the manufacturing efficiency can be improved, and the width of the required strip steel plate 8 can be made shorter compared to the case of simply arranging them in two rows, and the equipment can be miniaturized. Also, since the splitting position is between the slots 3, the risk of damage to the insulating paper attached to the slots 3 can be reduced.

[0025] In the method for manufacturing the stator core 1 for a coreless motor, in the step of forming the split core pieces 4, the strip steel plate 8 is punched so that the groove portions 7 of the split core pieces 4 in each row become both ends in the width direction of the strip steel plate 8, thereby forming the split core pieces 4. When the groove portions 7 are formed in the split core pieces 4, the width (W1) thereof becomes shorter than the width (W0) in the state where the groove portions 7 are not formed. Therefore, by punching so that the groove portions 7 become both ends, the width of the required strip steel plate 8 can be shortened, and the portions outside the split core pieces 4 that have to be discarded after punching can be reduced in advance.

[0026] Also, in the method for manufacturing the stator core 1 for a coreless motor, in the step of forming the split core pieces 4, the center line in the circumferential direction of the split core pieces 4 is inclined with respect to the width direction of the strip steel plate 8, and the strip steel plate 8 is punched so that the positions of the ends of the adjacent split core pieces 4 in the same row overlap at least in the feed direction of the strip steel plate 8, thereby forming the split core pieces 4. As a result, the length in the feed direction required to form one split core piece 4 becomes shorter, and the amount of use of the strip steel plate 8 can be greatly reduced when forming a large number of split core pieces 4.

[0027] In the embodiment, the split core piece 4 having a shape in which the core material 2 is divided into three equal parts in the circumferential direction is exemplified. However, as shown in FIG. 6, a split core piece 14 having a shape in which it is divided into four equal parts in the circumferential direction can also be used. This split core piece 14 is generally arc-shaped with an angle of 90° formed between both ends and the center point in the circumferential direction. A plurality of slots 3 are formed on the inner peripheral side, a convex portion 5 is formed at one end in the circumferential direction, and a concave portion 6 is formed at the other end. Further, a groove portion 7 is formed on the outer peripheral side of the split core piece 14, and its width (W11) is shorter than the width (W10) in a state where the groove portion 7 is not present.

[0028] Further, the split core piece 14 is in a state of being arranged in a staggered pattern of two rows, namely row A and row B, in the width direction of the strip steel plate 8 according to the procedure shown in FIG. 3. As shown in FIG. 7, the outer peripheral side of the split core piece 14 in each row is located on the outer side in the width direction of the strip steel plate 8. The convex portion 5 is located on the inner peripheral side of the split core piece 14 in the other row as shown in the region (R11) of the broken line, and the end portion where the concave portion 6 is formed as shown in the region (R12) of the broken line faces the end portion where the concave portion 6 is formed in the split core piece 14 in the other row. It is formed by punching the strip steel plate 8.

[0029] At this time, in each of the split core pieces 14, the groove portion 7 is located on each end side in the width direction of the strip steel plate 8 in both row A and row B. It can also be formed in a state where the center line (CL3) is inclined with respect to the width direction of the strip steel plate 8, or in a manner where the positions of the ends of the split core pieces 14 adjacent to each other in the same row overlap at least in the feed direction of the strip steel plate 8. Even in the case of such split core pieces 14, the utilization rate of the strip steel plate 8 can be improved, and the width and the length in the feed direction of the required strip steel plate 8 can be reduced. Thus, various effects similar to those of the embodiment can be obtained.

[0030] In addition to being divided into three or four equal parts in the circumferential direction, the divided core pieces can also have, for example, a shape divided into two, six, or eight equal parts in the circumferential direction. In this case, the number of divisions can be appropriately set according to the number and shape of the slots 3. Further, in order to facilitate division, the number of divisions can be set as a divisor of 360, or in order to facilitate assembly, the division position can be set between adjacent slots 3.

[0031] In the embodiment, a configuration in which the groove portion 7 is formed at the center on the outer peripheral side is illustrated. However, for example, a configuration in which a fixing portion for fixing the stator core 1 is provided on the outer peripheral side can be adopted. In this case, for example, in the case of the divided core piece 4, by adopting a shape in which the fixing portion is located between the divided core pieces 4 adjacent in the same column in FIG. 4 and the like, the fixing portion can be formed without widening the width of the strip steel plate 8.

[0032] In the embodiment, an example in which the center line (CL1) of the divided core piece 4 or the center line (CL3) of the divided core piece 14 is inclined with respect to the width direction is shown. However, the divided core piece 4 and the divided core piece 14 can also be formed in a non-inclined state. Further, in the embodiment, an example in which substantially the entire ends on the side where the concave portion 6 is formed face each other is shown. However, when the number of divisions is large, at least a part of the ends may face each other.

[0033] Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and its equivalent scope.

Explanation of Reference Numerals

[0034] In the drawings, 1 represents a stator core, 4, 4A, 4B, and 14 represent divided core pieces, 5 represents a convex portion, 6 represents a concave portion, 7 represents a groove portion, and 8 represents a strip steel plate.

Claims

1. A method for manufacturing a stator core for a coreless motor, comprising: a step of punching a strip steel plate to form divided core pieces; a step of laminating the divided core pieces while combining them in the circumferential direction to form the stator core, wherein the divided core pieces are arc-shaped equally divided in the circumferential direction of the stator core, have a convex portion protruding outward from one end in the circumferential direction at one end, and have a concave portion recessed from the other end and combined with the convex portion of another adjacent divided core piece at the other end; In the step of forming the divided core pieces, the divided core pieces are arranged in two rows in the width direction of the strip steel plate, the outer peripheral side of the divided core pieces in each row is located on the outer side in the width direction of the strip steel plate, the convex portion of the divided core pieces is located on the inner peripheral side of the divided core pieces in the other row, and the strip steel plate is punched so that the end portion where the concave portion of the divided core pieces is formed faces the end portion where the concave portion of the divided core pieces in the other row is formed, thereby forming the divided core pieces, which is a method for manufacturing a stator core for a coreless motor.

2. The divided core pieces are formed in a shape having groove portions for fixing by welding or fastening on the outer peripheral side, In the step of forming the divided core pieces, the strip steel plate is punched so that the groove portions of the divided core pieces in each row become both ends in the width direction of the strip steel plate, thereby forming the divided core pieces, which is a method for manufacturing a stator core for a coreless motor according to Claim 1.

3. In the step of forming the divided core pieces, the center line in the circumferential direction of the divided core pieces is inclined with respect to the width direction of the strip steel plate, and the strip steel plate is punched so that the positions of the ends of the adjacent divided core pieces in the same row overlap at least in the feeding direction of the strip steel plate, thereby forming the divided core pieces, which is a method for manufacturing a stator core for a coreless motor according to Claim 1 or 2.

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