JP2014241701A - Method of manufacturing stator core - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a stator core, which can suppress a decrease in the accuracy of form of the stator core.SOLUTION: A method of manufacturing a stator core 12 by stacking a plurality of block cores 11 formed by stacking a plurality of annular core pieces 10 includes the steps of: annealing each of the block cores 11; vertically stacking the plurality of block cores 11 by aligning the block cores 11, on the basis of a vertical part 14 arranged within a rotor space part 13 formed in the central part of the block core 11 after annealing; and integrating the block cores 11 together by joining the adjacent block cores 11 of the stacked block cores 11 together.

Description

The present invention relates to a method for manufacturing a stator core with high shape accuracy.

For example, in the manufacture of an IPM motor (embedded permanent magnet synchronous motor), iron core pieces are punched from an electromagnetic steel sheet and laminated to manufacture a laminated core (stator core and rotor core). And various joining methods, such as caulking, adhesion, and welding, are adopted for joining in the lamination direction of an iron core piece, for example. Moreover, when laminating | stacking an iron core piece, in order to eliminate the influence of the board | plate thickness deviation of an electromagnetic steel plate, the transposition which turns and piles up a predetermined number of iron core pieces, for example is performed. For the inversion, in-die inversion in which a blank die is rotated in a punching die to rotate and pile up core pieces to produce a stator core, for example, as shown in FIG. The pieces 80 are caulked and laminated in the punching die to form the block iron cores 81, and then, as shown in FIG. 5 (B), a predetermined number of the block iron cores 81 taken out from the punching die are stacked and stacked. There is a mold outer roll in which the stator cores 83 are manufactured by joining the matching block cores 81 with each other through the welds 82.

Here, residual strain exists in the iron core piece 80 punched from the electromagnetic steel sheet. For this reason, when the stator core 83 is manufactured using the block core 81 in which the core pieces 80 in which residual strain exists are laminated, there is a problem that hysteresis loss occurs in the stator core 83 and motor performance decreases. Therefore, as described in Patent Document 1, after the stator core 83 is formed, the stator core 83 is annealed (for example, about 800 ° C.) in order to remove residual strain existing in the stator core 83. Slow cooling after heating) is widely performed.

JP 58-063119

As shown in FIG. 6A, the stator core 83 is annealed by placing a stator core 83 formed by welding a block core 81 on a pedestal 84 and feeding it to an annealing furnace (not shown). However, as shown in FIG. 6B, a phenomenon occurs in which the stator core 83 is tilted during annealing. This is because the pedestal 84 and a transport rail (not shown) that supports the pedestal 84 and guides the movement in the annealing furnace are slightly inclined (θ degrees) from the horizontal plane, so that the weight of the stator core 83 is reduced. This is because an unbalanced load is applied. As a result, as shown in FIG. 6C, when the stator core 83 after annealing is viewed in cross section, the position of the upper end opening center and the position of the lower end opening center of the rotor hole 85 provided in the stator core 83 Deviation δ is generated between them, and the perpendicularity of the stator core 83 is lowered, which adversely affects the motor performance. The phenomenon that the stator core 83 tilts after annealing becomes more significant as the thickness of the stator core 83 is increased for the purpose of obtaining a large motor torque, and it becomes difficult to maintain the accuracy of the stator core 83. .

This invention is made | formed in view of this situation, and it aims at providing the manufacturing method of the stator core which can suppress the fall of the shape precision of a stator core.

A method for manufacturing a stator core according to the present invention that meets the above-described object is a method for manufacturing a stator core that is manufactured by stacking a plurality of block cores formed by stacking a plurality of annular core pieces.
A step of annealing each of the block cores;
The step of aligning and vertically stacking the plurality of block iron cores after annealing, with reference to the vertical portion arranged on the assembly base,
A step of joining the block cores stacked together and integrating the adjacent block cores.

In the method for manufacturing a stator core according to the present invention, a plurality of the block cores can be stacked and simultaneously annealed.
Moreover, the said block iron core can also be annealed one by one.

In the method for manufacturing a stator core according to the present invention, the annular core pieces can be stacked via caulking portions.

In the method for manufacturing a stator core according to the present invention, the annular core piece includes an annular yoke piece portion, a plurality of protruding pieces provided on the outer periphery of the annular yoke piece portion, and the caulking portions formed respectively. Have
After the plurality of block iron cores are integrated, it is preferable that the protrusion formed by stacking the protruding pieces is removed from the annular yoke formed by stacking the annular yoke pieces.
Since the caulking portion is formed on the projecting piece portion of the annular core piece, when the annular core pieces are stacked, the block iron core is formed by caulking joining of the projecting pieces, and the annular yoke portion of the block iron core is the annular yoke piece. The parts are simply stacked (the annular yoke piece is not crimped).

In the method for manufacturing a stator core according to the present invention, it is preferable that the block cores are stacked by being rotated by a predetermined angle.

In the method of manufacturing a stator core according to the present invention, even if the block core is inclined after annealing, the plurality of post-annealed cores are aligned and aligned with respect to the vertical portion arranged on the assembly base. Therefore, it is possible to reduce the influence of the inclination of the block core and suppress the reduction in the perpendicularity of the stator core.

In the method for manufacturing a stator core according to the present invention, when a plurality of block cores are stacked and simultaneously annealed, the block cores can be efficiently annealed.

In the method for manufacturing a stator core according to the present invention, when the block cores are annealed one by one, even when manufacturing a stator core having a large thickness, it can be manufactured with existing annealing equipment, and annealed. It is no longer necessary to install new annealing equipment such as increasing the size of the furnace. Moreover, since the unbalanced load due to the own weight applied to each block iron core is reduced, the inclination of each block iron core is further reduced, and the reduction in the perpendicularity of the stator iron core can be further suppressed.

In the method for manufacturing a stator core according to the present invention, when the annular core pieces are stacked via the crimping portion, the block core is easily manufactured.

In the method for manufacturing a stator core according to the present invention, the annular core piece includes an annular yoke piece portion, and a plurality of protruding piece portions provided on the outer periphery of the annular yoke piece portion, each of which has a crimped portion. After the plurality of block iron cores are integrated, when the projecting portion formed by stacking the projecting piece portions is removed from the annular yoke portion formed by stacking the annular yoke piece portions, the crimped portion is formed on the annular yoke portion. Since it does not exist, there is no caulking portion in the stator core formed by stacking the annular yoke portions, and there is no increase in iron loss due to interlayer short circuit in the stator core.

In the method of manufacturing a stator core according to the present invention, when stacking each block core by rotating it by a predetermined angle, the annular core piece has a plate thickness deviation due to the influence of the plate thickness deviation of the electromagnetic steel plate, and the height of the block core Even if there is a deviation, it is possible to prevent the deviation from occurring in the height of the stator core.

(A)-(D) are explanatory drawings of the manufacturing method of the stator core which concerns on the 1st Embodiment of this invention. (A)-(C) are explanatory drawings of the manufacturing method of the stator core which concerns on the 2nd Embodiment of this invention. It is explanatory drawing of the modification of the manufacturing method of the stator core which concerns on the 1st, 2nd embodiment of this invention. (A)-(C) are explanatory drawings of the manufacturing method of the stator core which concerns on the 3rd Embodiment of this invention. (A), (B) is explanatory drawing of the manufacturing method of the stator core which concerns on a prior art example. (A)-(C) are explanatory drawings which show each state before annealing, during annealing, and after annealing in the manufacturing method of the stator core which concerns on a prior art example.

Next, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention.
The stator core manufacturing method according to the first embodiment of the present invention includes a block core 11 formed by laminating a plurality of annular core pieces 10 as shown in FIGS. It is a manufacturing method of the stator core 12 manufactured by stacking a plurality of pieces, and is arranged in a step of annealing each block core 11 and in a rotor space 13 formed in the central portion of the block core 11 after annealing. A step of aligning and vertically stacking a plurality of block cores 11 with reference to a post 14 having a circular cross section as an example of a vertical section, and welding adjacent block cores 11 of the stacked block cores 11 (an example of joining) And the step of integrating the block iron core 11. Details will be described below.

The annular core piece 10 is formed by punching from a magnetic steel sheet (not shown) having a thickness of 0.5 mm or less, for example, and a plurality of the punched annular core pieces 10 are sequentially stacked to form the block core 11. Here, when the annular core piece 10 is punched from the magnetic steel sheet, a caulking portion (not shown) is simultaneously formed at a predetermined position of the annular core piece 10, so when the annular core piece 10 is laminated in the punching die, the lower layer A caulking joint is formed (caulking lamination) between the caulking portion of the annular core piece 10 and the caulking portion of the upper annular core piece 10. As a result, a rotor space portion 13 in which a hole provided in the center portion of the annular core piece 10 is continuously formed is provided in the center portion of the block core 11.

As shown in FIG. 1 (A), a plurality of block cores 11 are stacked on an annealing pedestal 15 (for example, the number necessary for forming the stator core 12), and the annealing pedestal 15 and the annealing pedestal 15 together with an annealing furnace (not shown) enter the furnace. Send in. The sent annealing pedestal 15 moves on a transport rail (not shown) installed in the annealing furnace toward the outlet of the annealing furnace, and annealing is performed during this time. By stacking a plurality of block cores 11 on the annealing pedestal 15 and simultaneously annealing them, the block cores 11 can be efficiently annealed.

Since the annealing pedestal 15 is slightly inclined (θ degrees) from the horizontal plane, the stacked block cores 11 are annealed in a state where an eccentric load is applied. As a result, the block cores 11 stacked on the annealing pedestal 15 are inclined on the annealing pedestal 15 after the annealing, as shown in FIG. 1 (B), and formed on the block core 11 disposed at the top. Deviation δ1 occurs between the position of the center of the upper end opening of the rotor space portion 13 and the position of the center of the lower end opening of the rotor space portion 13 formed in the block iron core 11 disposed at the lowermost portion. ing. Here, the unbalanced load applied to the block core 11 is the sum of its own weight and the weight of each block core 11 stacked on the upper side, so that a larger unbalanced load is applied to the block core 11 arranged on the lower side. For this reason, the deviation between the upper end opening center position and the lower end opening center position of the rotor space portion 13 formed in the block core 11 after annealing is minimized in the block core 11 disposed at the uppermost part during annealing. The block core 11 disposed on the lower side becomes larger.

As shown in FIG. 1C, the post-annealed block iron core 11 has a columnar post 14 provided perpendicular to the assembly base 16, and is used for the rotor formed in the center of the block iron core 11. Stacking is performed on the assembly base 16 while performing alignment so as to pass through the space 13. When the post 14 is inserted into the rotor space portion 13 of the inclined block core 11, the outer peripheral surface of the post 14 is a part of the upper end opening and the lower end opening of the rotor space portion 13 formed in the block core 11. The block core 11 is positioned with respect to the post 14 as a reference. Here, when the block cores 11 are stacked on the assembly base 16, the block cores 11 are rotated by a predetermined angle and stacked. As a result, even if a thickness deviation exists in the annular core piece 10 due to the influence of the thickness deviation of the electromagnetic steel sheet and a deviation occurs in the height of the block core 11, a deviation occurs in the height of the stator core 12. Can be suppressed.

For example, the block cores 11 stacked on the assembly base 16 are spot-welded to each other in a state where the block cores 11 are pressed from above and below, and a weld 17 is provided between the block cores 11 as shown in FIG. And the block core 11 is integrated. Thereby, the stator core 12 is formed. In each integrated block iron core 11 (stator iron core 12), each block iron core 11 is positioned with reference to the post 14, and therefore the rotor space 13 formed in the block iron core 11 arranged at the uppermost position. The deviation δ2 between the center position of the upper end opening and the lower end opening center position of the rotor space 13 formed in the block core 11 disposed at the lowermost portion is a deviation δ1 (see FIG. 5) generated in the stacked block cores 11 after annealing. 1 (see (B)). Therefore, even if the block iron cores 11 are inclined due to annealing, the influence (deviation δ2) of the inclination of the block iron cores 11 can be reduced in the stator iron core 12, and the perpendicularity of the stator iron core 12 is reduced. Can be suppressed.

As shown in FIGS. 2A to 2C, the stator core manufacturing method according to the second embodiment of the present invention is compared with the stator core manufacturing method according to the first embodiment. The plurality of block cores 19 used for forming the stator core 18 are characterized by annealing one by one. For this reason, the effect | action about annealing the block iron core 19 one by one is demonstrated. In the stator core manufacturing method according to the first embodiment, the same constituent members are denoted by the same reference numerals, and the description thereof is omitted.

Since the annealing pedestal 15 is slightly inclined (θ degrees) with respect to the horizontal plane, an uneven load due to its own weight is applied to the block core 19 during annealing, and the uneven load at this time is the own weight of one block core 19. It will be based on. Therefore, the amount of deviation δ3 between the upper end opening center position and the lower end opening center position of the rotor space 13 formed in the block core 19 after annealing is the same as that of the stator core according to the first embodiment. In the manufacturing method, it substantially coincides with the amount of deviation generated in the block core 11 disposed at the uppermost part during annealing.

As shown in FIG. 2B, the inclined block iron core 19 after annealing is provided with a columnar post 14 provided perpendicularly to the assembly base 16 for the rotor formed in the center of the block iron core 19. While aligning so as to pass through the space 13, the assembly is rotated by a predetermined angle and stacked on the assembly base 16. As a result, a part of the upper end opening and a part of the lower end opening of the rotor space 13 formed in the inclined block iron core 19 and the outer peripheral surface of the post 14 come into contact with each other. The iron core 19 is positioned, and even if there is a deviation in the thickness of the annular core 10 due to the influence of the deviation of the thickness of the electromagnetic steel sheet, the height of the stator core 18 is increased. It is possible to suppress the occurrence of deviations.

For example, the block cores 19 stacked on the assembly base 16 are spot welded to each other while pressing the block cores 19 adjacent to each other while being pressed from above and below, and as shown in FIG. And the block iron core 19 is integrated. Thereby, the stator core 18 is formed. In each integrated block iron core 19 (stator iron core 18), each block iron core 19 is positioned with reference to the post 14, and therefore, in the rotor space 13 of each block iron core 19, the upper end opening center position and the lower end The opening center positions are substantially coaxial, and the deviation δ3 between the upper end opening center position and the lower end opening center position of the stator core 18 is smaller than the deviation δ2 shown in FIG. Accordingly, it is possible to further suppress the decrease in perpendicularity of the stator core 18 by suppressing the inclination generated in each block core 19 by annealing (decreasing the deviation δ3).

In the first and second embodiments, the block iron cores 11 and 19 after annealing are positioned, the block iron cores 11 and 19 are stacked vertically, and the adjacent block iron cores 11 and 19 are spot-welded to each other. , 19 to form the welded portions 17 and 20 and integrate the block cores 11 and 19, but as shown in FIG. 3, at a plurality of positions along the circumferential direction of the vertically stacked block cores 11 and 19, The stator cores 12 and 18 may be configured by completely welding the annular core pieces 10 in the stacking direction, forming the weld bead portion 21 and integrating the block cores 11 and 19.

As shown in FIGS. 4A to 4C, the method for manufacturing the stator core according to the third embodiment of the present invention is the same as the method for manufacturing the stator core according to the first and second embodiments. Compared to the above, the method of forming the annular core piece 22 is different. For this reason, the effect | action of the formed annular core piece 22 is demonstrated.
For example, an annular core piece 22 formed by punching out from an electromagnetic steel sheet (not shown) having a thickness of 0.5 mm or less is formed along the circumferential direction on the radially inner side of the annular yoke piece portion 23 and the annular yoke piece portion 23. A plurality of magnetic pole piece portions 26 formed at equal intervals and a plurality of protruding piece portions 25 provided on the outer periphery of the annular yoke piece portion 23 and provided with caulking portions 24 are provided. Here, the projecting piece portion 25 is half-punched or punched out from the annular yoke piece portion 23 and then driven back against the annular yoke piece portion 23, so that the projecting piece portion 25 and the annular yoke piece portion 23 are in a connected state. It has become. Then, when the punched annular core pieces 22 are stacked in the punching die, a crimp joint is formed between the crimped portion 24 of the lower annular core piece 22 and the crimped portion 24 of the upper annular core piece 22, and the block An iron core 27 is formed. Here, the block iron core 27 is formed by stacking an annular yoke portion 28 formed by stacking the annular yoke piece portions 23, a projecting portion 29 formed by stacking the projecting piece portions 25, and a magnetic pole piece portion 26. A rotor space portion 31 is formed in an inner region that includes the magnetic pole portion 30 and is surrounded by the plurality of magnetic pole portions 30.

The formed block iron cores 27 are placed one by one on the annealing pedestal 15 and annealed in the same manner as in the method of manufacturing the stator iron core according to the second embodiment. Since the annealing pedestal 15 is slightly inclined with respect to the horizontal plane, an uneven load due to its own weight is applied to the block core 27 during annealing, and the center of the upper end opening of the rotor space 31 formed in the block core 27 after annealing is applied. There is a deviation between the position and the center position of the lower end opening. For this reason, the column-shaped post 14 provided perpendicularly to the assembly base 16 passes through the rotor space 13 formed in the center of the block core 27 through the inclined block core 27 after annealing. While being aligned with each other, they are rotated on the assembly base 16 by a predetermined angle and stacked. As a result, the block cores 27 are aligned with respect to the post 14, and even if the block cores 27 are inclined due to annealing, the block cores 27 can be stacked vertically, and the stator cores 32 (FIG. 4 ( C))) can be suppressed, and even if there is a thickness deviation in the annular core piece 22 due to the influence of the thickness deviation of the electromagnetic steel sheet, and the height of the block core 27 has a deviation, It can suppress that a deviation generate | occur | produces in the height of the stator core 32. FIG.

For example, in a state where the block cores 27 stacked on the assembly base 16 are pressed from above and below, the annular core pieces 22 are all welded in the stacking direction at a plurality of positions along the circumferential direction of the stacked block cores 27. As shown in FIG. 4B, when the weld bead portion 33 is formed and the plurality of block iron cores 27 are integrated, the annular yoke portion 28, the protruding portion 29, and the magnetic pole portion 30 of each block iron core 27 also come into contact with each other. And integrate. Here, since the projecting piece portion 25 formed by punching is pushed back to the annular yoke piece portion 23 and is connected via the punched portion (cut portion), in the stacked block core 27, the lowermost annular portion 25 is formed. When the yoke portion 28 is supported from below and the uppermost protrusion 29 is pressed downward, the protrusion 29 can be slid downward, removing the protrusion 29 from the annular yoke 28, As shown in FIG. 4C, a stator core 32 composed of the stacked annular yoke portion 28 and magnetic pole portion 30 can be formed.

As described above, the present invention has been described with reference to the embodiment. However, the present invention is not limited to the configuration described in the above-described embodiment, and the matters described in the scope of claims. Other embodiments and modifications conceivable within the scope are also included.
Further, the present invention also includes a combination of components included in the present embodiment and other embodiments and modifications.
For example, a block core can be formed by stacking annular core pieces punched from an electromagnetic steel sheet while rotating them by a certain angle.
When the block cores after annealing are stacked vertically on the assembly pedestal, a plurality of post-like vertical portions that contact the block core are provided on the assembly pedestal in some of the plurality of slot portions formed between the magnetic pole portions, It is good also as a standard of positioning.
Alternatively, the projecting piece may be removed by cutting the projecting portion after stacking the annular iron core pieces without integrating or projecting the projecting piece portion from the annular yoke piece portion, and then integrating the block core.

10: annular core piece, 11: block core, 12: stator core, 13: space for rotor, 14: post, 15: annealing base, 16: assembly base, 17: welded part, 18: stator core, 19: Block iron core, 20: Welded part, 21: Welded bead part, 22: Annular iron core piece, 23: Annular yoke piece part, 24: Caulking part, 25: Protruding piece part, 26: Magnetic pole piece part, 27: Block iron core , 28: annular yoke portion, 29: projecting portion, 30: magnetic pole portion, 31: space portion for rotor, 32: stator core, 33: weld bead portion

Claims (6)

In the manufacturing method of the stator core, which is manufactured by stacking a plurality of block cores formed by laminating a plurality of annular core pieces,
A step of annealing each of the block cores;
The step of aligning and vertically stacking the plurality of block iron cores after annealing, with reference to the vertical portion arranged on the assembly base,
A method of manufacturing a stator core, comprising: stacking the block cores and joining the adjacent block cores together. 2. The method of manufacturing a stator core according to claim 1, wherein a plurality of the block cores are stacked and simultaneously annealed. 2. The method of manufacturing a stator core according to claim 1, wherein the block cores are annealed one by one. The method for manufacturing a stator core according to any one of claims 1 to 3, wherein the annular core pieces are stacked via a caulking portion. 5. The method of manufacturing a stator core according to claim 4, wherein the annular core piece includes a plurality of annular yoke pieces and a plurality of protruding pieces provided on the outer periphery of the annular yoke piece, each of which is formed with a caulking portion. And
After the plurality of block iron cores are integrated, a projecting portion formed by stacking the projecting piece portions is removed from an annular yoke portion formed by stacking the annular yoke piece portions. Manufacturing method of iron core. The method for manufacturing a stator core according to any one of claims 1 to 5, wherein the block cores are stacked by being rotated by a predetermined angle.

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