Rotor manufacturing method, rotor and rotor core

Abstract

To provide a method for manufacturing a rotor that facilitates insertion of a rotating shaft into a through hole and improves the balance as a rotating body.SOLUTION: A manufacturing method comprises: a forming step of forming a core piece 22 while forming an elastically deformable spring portion 32 next to a part of a caulked projection 30 in the core piece 22; a temporary assembly step of temporarily assembling a rotor core 12 by stacking the plurality of core pieces 22 while caulking a plurality of caulked recesses 28 and the plurality of caulked projections 30 at a shallower position than a regular caulking position by elastic force of the spring portion 32; an insertion step of inserting a rotating shaft into a through hole formed in a shaft center of the rotor core 12 after the temporary assembly step; and a fixing step of axially pressurizing the rotor core 12 after the insertion step against the elastic force of the spring portion 32, and caulking the plurality of caulked recesses 28 and the plurality of caulked projections 30 to the regular caulking position.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a rotor for a rotating electrical machine, a rotor, and a rotor core. [Background technology]

[0002] Patent Document 1 below discloses a motor composed of a stator having a core made of laminated core pieces of electromagnetic steel sheets, and a rotor with embedded permanent magnets. In this motor, the stator and rotor use the same number of core pieces. The rotor core pieces have protrusions to form gaps between the laminated core pieces of the rotor. The height of the protrusions is set to 5 to 20% of the plate thickness of the core pieces. This allows the rotor to be manufactured with a stack thickness greater than that of the stator in order to improve the motor's characteristics.

[0003] Patent Document 2 listed below discloses a core forming method for electrical equipment in which core pieces punched out from thin steel sheets are stacked to form a laminated core. In this core forming method, protrusions are provided at approximately equal intervals on the core pieces, the core pieces are pressed between two parallel surfaces, the protrusions are crushed to approximately the same height as the thickest part of the core piece, and the core pieces in this state are stacked to form a laminated core. This maintains the parallelism of both end faces of the laminated core, improving the efficiency of the core forming process. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-10548 [Patent Document 2] Japanese Patent Application Publication No. 7-222409 Summary of the Invention [Problem to be solved by the invention]

[0005] When manufacturing a rotor for a rotating electric machine, several hundred thin core pieces, for example, approximately 0.25 to 0.35 millimeters thick, are stacked in a mold by crimping and then ejected from the mold. When stacking and crimping are performed in the mold, inclination of the core pieces occurs due to variations in sheet thickness and differences in the fit of the crimped fastening. To alleviate this inclination, the core pieces are rotated and stacked multiple times in the mold. However, when rotate stacking is performed in the mold, the time required for the rotation operation in the mold is limited, preventing an increase in the press rotation speed. For this reason, productivity can sometimes be improved by not performing the rotate stacking in the mold but instead rotating and stacking the stacked blocks of core pieces ejected from the mold. When the stacked blocks of core pieces are rotate stacked outside the mold, the direction of inclination between the blocks changes at the boundary between the rotate stacks. As a result, the through hole for the rotating shaft formed in the axial center of the rotor core has a zigzag shape. The degree of zigzag of the through hole varies depending on the electromagnetic steel sheet, which is the material of the core pieces, and the condition of the mold, making it difficult to control. If the through-hole has a large zigzag, it becomes impossible to insert the rotating shaft into the through-hole and assemble the rotating shaft to the rotor core. Even if the rotating shaft can be assembled to the rotor core, the rotor may not be balanced.

[0006] In consideration of the above, an object of the present invention is to provide a rotor manufacturing method, a rotor, and a rotor core that facilitate insertion of a rotating shaft into a through hole and that have good balance as a rotating body. [Means for solving the problem]

[0007] A first aspect of the method for manufacturing a rotor includes a rotor core made of a plurality of core pieces stacked together by crimping a plurality of crimping recesses formed on their upper surfaces and a plurality of crimping protrusions formed on their lower surfaces, and a rotating shaft inserted into a through hole formed in the axial center of the rotor core, and includes a molding process for molding the core pieces while forming elastically deformable spring portions in at least some of the crimping protrusions or adjacent to the crimping recesses in at least some of the core pieces; a temporary assembly process for stacking the core pieces while crimping the plurality of crimping recesses and the plurality of crimping protrusions at a position shallower than the normal crimping positions using the elastic force of the spring portions, and temporarily assembling the rotor core; an insertion process for inserting the rotating shaft into the through hole of the rotor core after the temporary assembly process; and a fixing process for applying axial pressure to the rotor core after the insertion process against the elastic force of the spring portions, and crimping the plurality of crimping recesses and the plurality of crimping protrusions to the normal crimping positions.

[0008] The first mode also includes a case where the elastically deformable spring portion undergoes plastic deformation.

[0009] A rotor manufacturing method according to a first aspect manufactures a rotor including a rotor core made of multiple stacked core pieces, each stacked by crimping multiple crimping recesses formed on its upper surface and multiple crimping protrusions formed on its lower surface, and a rotating shaft inserted into a through hole formed in the axial center of the rotor core. In this manufacturing method, in the molding process, the core pieces are molded while forming elastically deformable spring portions on at least some of the crimping protrusions or adjacent to the crimping recesses in at least some of the core pieces. In the temporary assembly process, the multiple core pieces are stacked while crimping the multiple crimping recesses and multiple crimping protrusions at positions shallower than the normal crimping positions using the elastic force of the spring portions, thereby temporarily assembling the rotor core. In the insertion process, the rotating shaft is inserted into the through hole of the rotor core after the temporary assembly process. In the fixing process, the rotor core after the insertion process is pressurized in the axial direction against the elastic force of the spring portions, thereby crimping the multiple crimping recesses and multiple crimping protrusions to the normal crimping positions. In the rotor core after the preliminary assembly process, the spring portions impart springiness in the stacking direction, imparting elasticity to the shape of the rotor core, making it easier to insert the rotating shaft into the through hole. Moreover, because the shape of the rotor core can be made to match the rotating shaft, the rotor has good balance as a rotating body.

[0010] A rotor manufacturing method of a second aspect is the method of the first aspect, in which a pair of the spring portions are formed so as to be point symmetrical with respect to the center of the at least some of the crimping protrusions.

[0011] In the rotor manufacturing method of the second aspect, a pair of spring portions is formed so as to be point symmetrical with respect to the center of at least some of the crimping protrusions, which allows the crimping recesses and the crimping protrusions to be crimped stably in parallel with the lamination direction of the core laminations.

[0012] A rotor manufacturing method of a third aspect is the same as that of the first or second aspect, in which at least some of the crimping protrusions are formed in a rectangular shape, and the spring portions are formed on both sides of the at least some of the crimping protrusions in the longitudinal direction.

[0013] In the rotor manufacturing method of the third aspect, at least some of the crimping protrusions are formed in a rectangular shape, and at least some of the crimping protrusions have spring portions formed on both longitudinal sides thereof, which stabilizes the elastic force of the spring portions and allows the crimping recesses and crimping protrusions to be crimped more reliably at positions shallower than the normal crimping positions.

[0014] The manufacturing method of the rotor of the fourth aspect is any one of the first to third aspects, in which when n adjacent core pieces are used as a set, the number of crimping protrusions formed on each of the core pieces is a multiple of n, and in each of the core pieces, the spring portions are formed next to the number of crimping protrusions equal to the number of crimping protrusions divided by n, and when the set of core pieces is viewed from the axial direction, the spring portions are positioned next to all of the crimping protrusions.

[0015] In the rotor manufacturing method of the fourth aspect, when n adjacent core pieces are used as a set, the number of crimping protrusions formed on each core piece is a multiple of n, and spring parts are formed next to the number of crimping protrusions equal to the number of crimping protrusions divided by n in each core piece, so that the spring parts are arranged next to all of the crimping protrusions when the set of core pieces is viewed in the axial direction. This allows sufficient elastic force to be applied to each core piece.

[0016] The manufacturing method of the rotor of the fifth aspect is any one of the first to third aspects, in which when two adjacent core pieces are made into a set, the number of crimping protrusions formed on each of the core pieces is a multiple of 2, and in each of the core pieces, the spring portions are formed next to the number of crimping protrusions equal to the number of crimping protrusions divided by 2, and when the set of core pieces is viewed from the axial direction, the spring portions are positioned next to all of the crimping protrusions.

[0017] In the rotor manufacturing method of the fifth aspect, when two adjacent core pieces are combined into a set, the number of crimping protrusions formed on each core piece is a multiple of 2, and spring portions are formed next to the number of crimping protrusions in each core piece equal to the number of crimping protrusions divided by 2, so that when the set of core pieces is viewed in the axial direction, the spring portions are positioned next to all of the crimping protrusions. This makes it possible to impart even more sufficient elastic force to each core piece.

[0018] A rotor manufacturing method of a sixth aspect is the same as that of the fourth or fifth aspect, wherein the spring portions are formed adjacent to the plurality of crimping protrusions that are continuously arranged in the circumferential direction of the core piece.

[0019] In the rotor manufacturing method of the sixth aspect, spring portions are formed adjacent to each of the multiple crimping protrusions that are continuously arranged in the circumferential direction of the core pieces, which increases the irregularity of the core pieces and makes it easier to assemble the rotating shaft.

[0020] The rotor of the seventh aspect is a rotor comprising a rotor core consisting of a plurality of core pieces stacked together by crimping and fitting together a plurality of crimping recesses formed on the upper surface of each piece and a plurality of crimping protrusions formed on the lower surface of each piece, and a rotating shaft inserted into a through hole formed in the axial center of the rotor core, wherein elastically deformable spring portions are formed next to at least some of the crimping protrusions in at least some of the core pieces, and the plurality of crimping recesses and the plurality of crimping protrusions are crimped together while the spring portions are elastically pressurized in the axial direction of the rotor core.

[0021] In a rotor according to a seventh aspect, the rotor core is made of a plurality of stacked core pieces, each having a plurality of crimping recesses formed on its upper surface and a plurality of crimping protrusions formed on its lower surface, which are crimped and fitted together. A rotating shaft is inserted into a through hole formed in the axial center of the rotor core. In this rotor, elastically deformable spring portions are formed adjacent to at least some of the crimping protrusions in at least some of the core pieces. The spring portions are elastically pressurized in the axial direction of the rotor core, and the plurality of crimping recesses and the plurality of crimping protrusions are crimped together. This rotor can be manufactured by the rotor manufacturing method according to the first aspect, and therefore has the same effects as the first aspect.

[0022] In an eighth aspect of the rotor, in the seventh aspect, a pair of the spring portions are formed so as to be point symmetrical with respect to the center of the at least some of the crimping protrusions.

[0023] In the rotor of the eighth aspect, a pair of spring portions is formed so as to be point symmetrical with respect to the center of at least some of the crimping protrusions, thereby enabling the crimping recesses and the crimping protrusions to be crimped stably in parallel with the lamination direction of the core laminations.

[0024] A rotor of a ninth aspect is the rotor of the seventh or eighth aspect, wherein the crimping protrusions are rectangular in shape, and the spring portions are formed on both sides of the longitudinal direction of at least some of the crimping protrusions.

[0025] In the rotor of the ninth aspect, at least some of the crimping protrusions are formed in a rectangular shape, and at least some of the crimping protrusions have spring portions formed on both longitudinal sides thereof, which stabilizes the elastic force of the spring portions and allows the crimping recesses and crimping protrusions to be crimped more reliably at positions shallower than the normal crimping position.

[0026] A rotor of a tenth aspect is any one of the seventh to ninth aspects, in which when n adjacent core pieces are considered as a set, the number of crimping protrusions formed on each of the core pieces is a multiple of n, and in each of the core pieces, the spring portions are formed next to the number of crimping protrusions equal to the number of crimping protrusions divided by n, and when the set of core pieces is viewed from the axial direction, the spring portions are arranged next to all of the crimping protrusions.

[0027] In the rotor of the tenth aspect, when n adjacent core pieces are used as a set, the number of crimping protrusions formed on each core piece is a multiple of n, and spring portions are formed next to the crimping protrusions in each core piece equal to the number of crimping protrusions divided by n, so that when the set of core pieces is viewed from the axial direction, the spring portions are arranged next to all of the crimping protrusions. This allows sufficient elastic force to be applied to each core piece.

[0028] The rotor of the 11th aspect is any one of the 7th to 9th aspects, in which when two adjacent core pieces are combined into a set, the number of crimping protrusions formed on each of the core pieces is a multiple of 2, and in each of the core pieces, the spring portions are formed next to the number of crimping protrusions equal to the number of crimping protrusions divided by 2, and when the set of core pieces is viewed from the axial direction, the spring portions are arranged next to all of the crimping protrusions.

[0029] In the rotor of the eleventh aspect, when two adjacent core pieces are combined into a set, the number of crimping protrusions formed on each core piece is a multiple of 2, and spring portions are formed next to the number of crimping protrusions in each core piece equal to the number of crimping protrusions divided by 2, so that when the set of core pieces is viewed in the axial direction, the spring portions are arranged next to all of the crimping protrusions. This makes it possible to apply even more sufficient elastic force to each core piece.

[0030] A rotor of a twelfth aspect is the rotor of the tenth or eleventh aspect, wherein the spring portions are formed adjacent to the plurality of crimping protrusions that are continuously arranged in the circumferential direction of the core pieces.

[0031] In the rotor of the twelfth aspect, a spring portion is formed adjacent to each of the multiple crimping protrusions that are continuously arranged in the circumferential direction of the core pieces, thereby increasing the irregularity of the core pieces and further improving the ease of assembling the rotating shaft.

[0032] The rotor core of the thirteenth aspect is a rotor core made up of a plurality of core pieces stacked together by crimping a plurality of crimping recesses formed on the upper surface of each core piece with a plurality of crimping protrusions formed on the lower surface of each core piece, and an elastically deformable spring portion is formed next to at least some of the crimping protrusions in at least some of the core pieces, and when the spring portion is elastically pressurized in the axial direction of the core pieces, the plurality of crimping recesses and the plurality of crimping protrusions are in a semi-crimped state, and when pressurized in the axial direction, the spring portion elastically deforms, and the plurality of crimping recesses and the plurality of crimping protrusions are fully crimped together.

[0033] A rotor core according to a thirteenth aspect comprises a plurality of stacked core pieces, each having a plurality of crimping recesses formed on its upper surface and a plurality of crimping protrusions formed on its lower surface, which are crimped and fitted together. In this rotor core, elastically deformable spring portions are formed adjacent to at least some of the crimping protrusions in at least some of the core pieces. The spring portions are elastically pressurized in the axial direction of the rotor core, and the plurality of crimping recesses and the plurality of crimping protrusions are in a semi-crimped state. This rotor core can be manufactured using the molding and pre-assembly steps of the rotor manufacturing method according to the first aspect, and therefore provides the same effects as the first aspect.

[0034] A rotor core according to a fourteenth aspect is the thirteenth aspect, wherein a pair of the spring portions are formed so as to be point symmetrical with respect to the center of the at least some of the crimping protrusions.

[0035] In the rotor core of the fourteenth aspect, a pair of spring portions is formed so as to be point symmetrical with respect to the center of at least some of the crimping protrusions, thereby enabling the crimping recesses and the crimping protrusions to be crimped stably in parallel with the lamination direction of the core laminations.

[0036] The rotor core of the 15th aspect is the 13th or 14th aspect, wherein the crimping protrusions are rectangular in shape, and the spring portions are formed on both sides of the longitudinal direction of at least some of the crimping protrusions.

[0037] In the rotor core of the fifteenth aspect, at least some of the crimping protrusions are formed in a rectangular shape, and at least some of the crimping protrusions have spring portions formed on both longitudinal sides thereof, which stabilizes the elastic force of the spring portions and allows the crimping recesses and crimping protrusions to be crimped more reliably at positions shallower than the normal crimping positions.

[0038] The rotor core of the 16th aspect is any one of the 13th to 15th aspects, in which when n adjacent core pieces are considered as a set, the number of crimping protrusions formed on each of the core pieces is a multiple of n, and in each of the core pieces, the spring portions are formed next to the number of crimping protrusions equal to the number of crimping protrusions divided by n, and when the set of core pieces is viewed from the axial direction, the spring portions are arranged next to all of the crimping protrusions.

[0039] In the rotor core of the sixteenth aspect, when n adjacent core pieces are considered as a set, the number of crimping protrusions formed on each core piece is a multiple of n, and spring portions are formed next to the number of crimping protrusions equal to the number of crimping protrusions divided by n in each core piece, so that when the set of core pieces is viewed from the axial direction, the spring portions are arranged next to all of the crimping protrusions. This allows sufficient elastic force to be applied to each core piece.

[0040] The rotor core of the 17th aspect is any one of the 13th to 15th aspects, in which when two adjacent core pieces are combined into a set, the number of crimping protrusions formed on each of the core pieces is a multiple of 2, and in each of the core pieces, the spring portions are formed next to the number of crimping protrusions equal to the number of crimping protrusions divided by 2, and when the set of core pieces is viewed from the axial direction, the spring portions are arranged next to all of the crimping protrusions.

[0041] In the rotor core of the seventeenth aspect, when two adjacent core pieces are combined into a set, the number of crimping protrusions formed on each core piece is a multiple of 2, and spring portions are formed next to the number of crimping protrusions in each core piece equal to the number of crimping protrusions divided by 2, so that when the set of core pieces is viewed in the axial direction, the spring portions are arranged next to all of the crimping protrusions. This makes it possible to impart even more sufficient elastic force to each core piece.

[0042] In the rotor core of an eighteenth aspect, in the sixteenth or seventeenth aspect, the spring portions are formed adjacent to the plurality of crimping protrusions that are continuously arranged in the circumferential direction of the core pieces.

[0043] In the rotor core of the eighteenth aspect, spring portions are formed adjacent to each of the multiple crimping protrusions that are continuously arranged in the circumferential direction of the core pieces, thereby increasing the irregularity of the core pieces and further improving the ease of assembling the rotating shaft. [Effects of the Invention]

[0044] As described above, in the rotor manufacturing method, rotor, and rotor core according to the present invention, the rotor shaft can be easily inserted into the through-hole, and the rotor is well balanced as a rotating body. [Brief explanation of the drawings]

[0045] [Figure 1] FIG. 2 is a front view showing the configuration of the rotor according to the embodiment. [Figure 2] FIG. 2 is a cross-sectional view showing a part of a cross section of the rotor core according to the embodiment. [Figure 3] FIG. 3 is a plan view showing a first core lamination. [Figure 4] FIG. 10 is a plan view showing a second core lamination. [Figure 5] FIG. 4 is a cross-sectional view showing a cross section of the periphery of a spring portion in a core piece. [Figure 6] FIG. 4 is a cross-sectional view showing a cross section of a rotor core in a comparative example. [Figure 7] FIG. 10 is a plan view showing a first core lamination according to a first modified example. [Figure 8] FIG. 10 is a plan view showing a second core lamination according to a first modified example. [Figure 9] FIG. 10 is a plan view showing a first core lamination according to a second modified example. [Figure 10] FIG. 10 is a plan view showing a second core lamination according to a second modified example. [Figure 11] FIG. 11 is a plan view showing a part of a first core lamination according to a third modified example. [Figure 12] FIG. 11 is a plan view showing a part of a second core lamination according to a third modified example. [Figure 13] FIG. 10 is a plan view showing a part of a first core lamination according to a fourth modified example. [Figure 14]FIG. 11 is a plan view showing a part of a second core lamination according to a fourth modified example. [Figure 15] FIG. 13 is a plan view showing a part of a first core lamination according to a fifth modified example. [Figure 16] FIG. 13 is a plan view showing a part of a second core lamination according to a fifth modified example. [Figure 17] FIG. 13 is a plan view showing a part of a first core lamination according to a sixth modified example. [Figure 18] FIG. 13 is a plan view showing a portion of a second core lamination according to a sixth modified example. [Figure 19] FIG. 13 is a plan view showing a spring portion according to a seventh modified example. [Figure 20] FIG. 13 is a plan view showing a spring portion according to an eighth modified example. [Figure 21] FIG. 13 is a plan view showing a spring portion according to a ninth modified example. [Figure 22] FIG. 23 is a side view showing a spring portion according to a tenth modified example. [Figure 23] FIG. 23 is a side view showing a spring portion according to an eleventh modified example. [Figure 24] FIG. 23 is a side view showing a spring portion according to a twelfth modified example. [Figure 25] FIG. 23 is a cross-sectional view showing a spring portion according to a thirteenth modified example. DETAILED DESCRIPTION OF THE INVENTION

[0046] A rotor 10 according to an embodiment of the present invention and a method for manufacturing the same will be described below with reference to Figures 1 to 5. The rotor 10 according to this embodiment is a rotor for rotating electrical machines for automobiles, home appliances, and other industrial fields, and is composed of a rotor core 12, a rotating shaft 14, and a plurality of permanent magnets 16, as shown in Figure 1.

[0047] The rotor core 12 is formed in a cylindrical shape, and a circular through-hole 18 is formed in the axial center of the rotor core 12, penetrating the rotor core 12 in the axial direction. A rotating shaft 14 is inserted into this through-hole 18. A plurality of (eight in this example) magnet insertion holes 20 are formed in the outer periphery of the rotor core 12, penetrating the rotor core 12 in the axial direction, and are arranged at equal intervals in the circumferential direction of the rotor core 12. For example, each magnet insertion hole 20 has an elongated rectangular shape with its longitudinal direction extending in the circumferential direction of the rotor core 12. A permanent magnet 16 is inserted into each of the magnet insertion holes 20. The permanent magnets 16 are fixed to the rotor core 12 using, for example, resin, and the rotating shaft 14 is fixed to the rotor core 12 by, for example, shrink fitting. The rotor core 12 is formed by stacking several hundred core pieces (iron core pieces) 22. FIG. 2 shows a portion of a cross section of the rotor core 12.

[0048] As shown in FIGS. 3 and 4, the core pieces 22 are formed in a disk shape. The core pieces 22 are made of electromagnetic steel sheets. A circular through-hole 24 is formed in the center of the core pieces 22. As shown in FIGS. 2 to 4, the outer periphery of each core piece 22 is formed with a plurality of (eight here) magnet insertion holes 26, a plurality of (eight here) crimping recesses 28, a plurality of (eight here) crimping protrusions 30, and a plurality of (eight here) spring portions 32. In the following description, one surface of the core piece 22 in the thickness direction is referred to as the "upper surface," and the other surface of the core piece 22 in the thickness direction is referred to as the "lower surface." In the following description, the core piece 22 shown in FIG. 3 may be referred to as the "first core piece 22A," and the core piece 22 shown in FIG. 4 may be referred to as the "second core piece 22B."

[0049] As an example, the magnet insertion holes 26 have a long rectangular shape (rectangular shape) with the longitudinal direction being the circumferential direction of the core pieces 22, and are arranged at equal intervals in the circumferential direction of the core pieces 22. When several hundred core pieces 22 are stacked, the through holes 24 of each core piece 22 form the through holes 18 of the rotor core 12, and the magnet insertion holes 26 of each core piece 22 form the magnet insertion holes 20 of the rotor core 12.

[0050] The crimping recesses 28, crimping protrusions 30, and spring portions 32 are formed on the inner peripheral side of the core pieces 22 with respect to the magnet insertion holes 26. The crimping recesses 28 are formed on the upper surfaces of the core pieces 22, and the crimping protrusions 30 are formed on the lower surfaces of the core pieces 22. These crimping recesses 28 and crimping protrusions 30 are formed by, for example, V-crimping or half-blanking crimping, and each crimping protrusion 30 is located directly below each crimping recess 28. As one example, these crimping recesses 28 and crimping protrusions 30 have an elongated rectangular shape (rectangular shape) whose longitudinal direction is in the radial direction of the core pieces 22, and are arranged side by side at equal intervals in the circumferential direction of the core pieces 22.

[0051] When the core pieces 22 are stacked, the multiple crimping recesses 28 formed on the upper surface of each core piece 22 are crimped and fitted into the multiple crimping protrusions 30 formed on the lower surface of each core piece 22. This fixes the core pieces 22 together in a stacked state. In Fig. 2, the multiple crimping recesses 28 and the multiple crimping protrusions 30 are in a semi-crimped state.

[0052] In the present embodiment, as an example, crimped protrusions 30A, in which a pair of adjacent spring portions 32 is formed, and crimped protrusions 30B, in which a pair of non-adjacent spring portions 32 is formed, are alternately arranged in the circumferential direction of the core laminations 22. The pair of spring portions 32 is disposed on both sides of the crimped protrusion 30A in the circumferential direction of the core laminations 22, and is formed point-symmetrically with respect to the center of the crimped protrusion 30A, with the spring portion 32 formed on each side in the longitudinal direction of the crimped protrusion 30A. As shown in FIG. 5 , the spring portions 32 protrude from the lower surface of the core laminations 22 in the thickness direction of the core laminations 22. Note that arrows Y and Z shown in FIG. 5 indicate the radial and axial directions of the rotor core 12, respectively. In the present embodiment, as an example, the spring portions 32 protrude in a trapezoidal cross section. The spring portion 32 is set to have a protruding height equal to or higher than the crimping protrusions 30A, 30B, and is elastically deformable in the thickness direction of the core piece 22. When a certain force is applied to the spring portion 32 in the thickness direction of the core piece 22, the spring portion 32 becomes flat or nearly flat.

[0053] The spring portions 32 may be disposed adjacent to the crimping protrusions 30A. For example, the spring portions 32 may be disposed on both radial sides of the crimping protrusions 30A of the core piece 22, or multiple spring portions 32 may be disposed asymmetrically around the crimping protrusions 30A, or only one spring portion 32 may be disposed around the crimping protrusions 30A. When the crimping protrusions 30A and 30B have an elongated rectangular shape, they may have a longitudinal direction in the circumferential direction of the core piece 22 or in a direction intersecting the radial and circumferential directions of the core piece 22. The protruding height of the spring portion 32 may be set to be lower than the protruding height of the crimping protrusions 30A and 30B.

[0054] When the core laminations 22 are stacked, the stacking phases of the core laminations 22 are shifted by a predetermined angle (here, 45 degrees). That is, the first core laminations 22A shown in FIG. 3 and the second core laminations 22B shown in FIG. 4 are alternately stacked. As a result, in the core laminations 22 stacked one above the other, the crimping protrusions 30A and 30B are alternately arranged vertically as shown in FIG. 2, and the spring portions 32 of adjacent core laminations 22 are arranged so as not to overlap in the thickness direction of the core laminations 22. The spring portion 32 formed adjacent to the crimping protrusion 30A of the upper core lamination 22 abuts against the upper surface of the lower core lamination 22, thereby elastically deforming the spring portion 32. The core laminations 22 are stacked while the elastic force of the spring portion 32 crimps the crimping recesses 28 and the crimping protrusions 30 at positions shallower than the normal crimping positions. That is, when the core pieces 22 are fastened by crimping, the crimping recesses 28 and the crimping protrusions 30 are not completely fitted together, resulting in a half-crimped state.

[0055] In this embodiment, when the core pieces 22 are stacked, and n adjacent core pieces 22 are grouped into a set, the number of crimping protrusions 30A, 30B formed on each core piece 22 is a multiple of n, and in each core piece 22, spring portions 32 are formed next to the crimping protrusions 30A in a number equal to (the number of crimping protrusions 30A, 30B divided by n), and when the set of core pieces 22 is viewed in the axial direction, the spring portions 32 are arranged next to all of the crimping protrusions 30A, 30B. More specifically, when two adjacent core pieces 22 are grouped into a set, the number of crimping protrusions 30A, 30B formed on each core piece 22 is a multiple of 2, and in each core piece 22, spring portions 32 are formed next to the crimping protrusions 30A in a number equal to (the number of crimping protrusions 30A, 30B divided by 2), and when the set of core pieces 22 is viewed in the axial direction, the spring portions 32 are arranged next to all of the crimping protrusions 30A, 30B.

[0056] The core pieces 22 are manufactured using, for example, a progressive die device (not shown). In this progressive die device, a laminated block manufacturing process is carried out to manufacture a plurality of laminated blocks (not shown). A laminated block is formed by stacking a large number of core pieces 22, and the rotor core 12 is manufactured by stacking a plurality of laminated blocks. In the laminated block manufacturing process, a forming process is carried out on a strip-shaped electromagnetic steel sheet (hoop material) to manufacture a large number of core pieces 22, and a pre-assembly process is carried out in which the large number of core pieces 22 are pre-assembled (pre-stacking) to manufacture a pre-assembled laminated block.

[0057] The forming process includes a first-half punching process and an outer diameter punching process. In the first-half punching process, various punching processes are sequentially performed on the strip-shaped electromagnetic steel sheet to form the basic shape of the core piece 22, excluding the outer shape. During this process, the electromagnetic steel sheet is intermittently transferred within a progressive die device and sequentially punched by multiple punches attached to an upper die that moves up and down. While being transferred progressively, intermittent punching is performed by multiple punches attached to an upper die that moves up and down. During this first-half punching process, a stripper (stripper plate) attached to the upper die descends to press the electromagnetic steel sheet against the upper surface of the lower die. During this first-half punching process, the core piece 22 shown in FIG. 3 and the core piece 22 shown in FIG. 4 are alternately formed by, for example, using the ON / OFF function of a slider.

[0058] After the first half punching step is completed, the outer shape punching step is carried out. During this step, the outer shape of the core pieces 22 is punched out using an outer shape punching punch attached to the upper die of the progressive die device. Once the core pieces 22 have been formed in this outer shape punching step, the preliminary assembly step is carried out. In the preliminary assembly step, a first half temporary assembly step and a second half temporary assembly step are carried out. In the first half temporary assembly step, the core pieces 22 punched out in the outer shape punching step are stacked one after another in a squeeze ring provided in the lower die below the outer shape punching punch. During this step, the core pieces 22 are stacked while the elastic force of the spring portion 32 crimps the multiple crimping recesses 28 and the multiple crimping protrusions 30 at a position shallower than the normal crimping position. This produces a laminated block in a preliminary assembly state.

[0059] The pre-assembled laminated blocks are ejected from the progressive die device and transported to the next process, the latter half pre-assembly process. In the latter half pre-assembly process, the plurality of laminated blocks are rotated and stacked (so-called block rotation). At this time, for example, each laminated block is rotated by a predetermined angle (e.g., 90 degrees) to shift the stacking phase. By this rotation and stacking, the rotor core 12 in the pre-assembled state is manufactured.

[0060] The rotor core 12 in the pre-assembled state is transported to the next process, the insertion process. In the insertion process, the rotating shaft 14 is inserted into the through hole 18 of the pre-assembled rotor core 12, and end plates (not shown) are attached to both axial ends of the rotor core 12, thereby manufacturing the pre-assembled rotor 10. The pre-assembled rotor 10 is transported to the next process, the fixing process. In the fixing process, the rotor core 12 after the insertion process is pressed axially against the elastic force of the spring portions 32 of each core piece 22, and the multiple crimping recesses 28 and the multiple crimping protrusions 30 are crimped to the correct crimping positions (final crimping). This completes the rotor 10. In the completed rotor 10, the multiple crimping recesses 28 and the multiple crimping protrusions 30 are crimped together while the spring portions 32 of each core piece 22 are elastically pressed in the axial direction of the rotor core 12. A part of each spring portion 32 is plastically deformed, and the amount of protrusion of each spring portion 32 in the stacking direction becomes equal to or less than the thickness of the core lamination (for example, approximately 20 to 50% of the thickness of the core lamination 22).

[0061] (Action and effect) Next, the operation and effects of this embodiment will be described.

[0062] In this embodiment, a rotor 10 is manufactured that includes a rotor core 12 consisting of multiple core pieces 22 that are stacked by crimping and fitting together multiple crimping recesses 28 formed on each upper surface and multiple crimping protrusions 30 formed on each lower surface, and a rotating shaft 14 that is inserted into a through hole 18 formed in the axial center of the rotor core 12.

[0063] In this manufacturing method for the rotor 10, in the molding process, the core pieces 22 are molded while forming elastically deformable spring portions 32 next to some of the crimping protrusions 30 in the core pieces 22. In the temporary assembly process, the core pieces 22 are stacked while the elastic force of the spring portions 32 crimps the crimping recesses 28 and the crimping protrusions 30 at positions shallower than the normal crimping positions, thereby temporarily assembling the rotor core 12. In the insertion process, the rotating shaft 14 is inserted into the through hole of the rotor core 12 after the temporary assembly process. In the fixing process, the rotor core 12 after the insertion process is pressed in the axial direction against the elastic force of the spring portions 32, and the crimping recesses 28 and the crimping protrusions 30 are crimped to the normal crimping positions.

[0064] In the rotor core 12 after the preliminary assembly process, the spring portions 32 impart springiness in the stacking direction, imparting elasticity to the shape of the rotor core 12, facilitating insertion of the rotating shaft 14 into the through hole 18. In particular, when a rotor core is manufactured by rotationally stacking laminated blocks, as in the comparative example shown in FIG. 6 , the tilt direction of laminated blocks B1, B2, B3, and B4 changes at the boundaries of the rotationally stacked laminated blocks, resulting in a zigzag shape for the through hole 18 for the rotating shaft, making it difficult to insert the rotating shaft into the through hole 18. However, this problem can be avoided in this embodiment. Moreover, in this embodiment, the elasticity of the spring portions 32 allows the shape of the rotor core 12 to conform to the rotating shaft 14, thereby significantly increasing and allowing for a larger tolerance for posture during manufacturing of the rotor core 12 and improving the balance of the rotor 10 as a rotating body.

[0065] In this embodiment, a pair of spring portions 32 are formed so as to be point symmetrical with respect to the center of the crimping protrusion 30A, thereby enabling the crimping recess 28 and the crimping protrusion 30 to be crimped stably in parallel with the lamination direction of the core pieces 22.

[0066] In this embodiment, the crimping protrusions 30A and 30B are formed in a rectangular shape, and the spring portions 32 are formed on both longitudinal sides of the crimping protrusion 30A. This stabilizes the elastic force of the spring portions 32, and allows the crimping recess 38 to be crimped to the crimping protrusion 30 more reliably at a position shallower than the normal crimping position.

[0067] Furthermore, in this embodiment, when n adjacent core pieces 22 are considered as a set, the number of crimping protrusions 30A, 30B formed on each core piece 22 is a multiple of n, and in each core piece 22, spring portions 32 are formed next to the crimping protrusions 30A in number equal to the number of crimping protrusions 30A divided by n, and when the set of core pieces 22 is viewed in the axial direction, the spring portions 32 are arranged next to all of the crimping protrusions 30A, 30B. This allows sufficient elastic force to be applied to each core piece 22.

[0068] More specifically, in this embodiment, when two adjacent core pieces 22 are made into a set, the number of crimping protrusions 30A, 30B formed on each core piece 22 is a multiple of 2, and in each core piece 22, spring portions 32 are formed next to the number of crimping protrusions 30A equal to the number of crimping protrusions 30A, 30B divided by 2, so that when the set of core pieces 22 is viewed in the axial direction, the spring portions 32 are arranged next to all of the crimping protrusions 30A, 30B. This makes it possible to apply even more sufficient elastic force to each core piece 22.

[0069] (Variation) Next, various modifications of the above embodiment will be described. The various modifications described below also provide the same functions and effects as the above embodiment.

[0070] In the first modified example, the rotor core 12 is manufactured by alternately stacking first core laminations 22A, a portion of which is shown in FIG. 7, and second core laminations 22B, a portion of which is shown in FIG. 8, one above the other. The first core laminations 22A shown in FIG. 7 have a pair of spring portions 32 formed adjacent to each of the four crimping protrusions 30A formed on one radial side, and the second core laminations 22B shown in FIG. 8 have a pair of spring portions 32 formed adjacent to each of the four crimping protrusions 30A formed on the other radial side. In this first modified example, a pair of spring portions 32 is formed adjacent to each of the multiple crimping protrusions 30A that are continuously aligned in the circumferential direction of the core laminations 22A and 22B. In this first modified example, the rotor core 12 is manufactured by alternately stacking the first core laminations 22A shown in FIG. 7 and the second core laminations 22B shown in FIG. 8. As a result, the spring portions 32 of the core pieces 22A and 22B stacked adjacently one above the other are arranged so as not to overlap in the thickness direction of the core pieces 22. In this first modified example, the irregularity of the core pieces 22 is increased, which can further improve the ease of assembling the rotating shaft 14.

[0071] In the second modified example, the rotor core 12 is manufactured by alternately stacking first core laminations 22A, a portion of which is shown in FIG. 9, and second core laminations 22B, a portion of which is shown in FIG. 10, vertically. One spring portion 32 is formed in the first core laminations 22A shown in FIG. 9 adjacent to one side of the core laminations 22A in the circumferential direction relative to the multiple crimping protrusions 30, and one spring portion 32 is formed in the second core laminations 22B shown in FIG. 10 adjacent to the other side of the core laminations 22B in the circumferential direction relative to the multiple crimping protrusions 30. In this second modified example, the rotor core 12 is manufactured by alternately stacking the first core laminations 22A shown in FIG. 9 and the second core laminations 22B shown in FIG. 10. As a result, the spring portions 32 of the core laminations 22A and 22B stacked adjacent to each other vertically are arranged so as not to overlap in the thickness direction of the core laminations 22.

[0072] In the third modified example, the rotor core 12 is manufactured by alternately stacking first core pieces 22A, a portion of which is shown in FIG. 11 , and second core pieces 22B, a portion of which is shown in FIG. 12 . In this third modified example, a substantially U-shaped spring portion 34 is formed adjacent to the crimping protrusion 30A in the first core piece 22A. This spring portion 34 is disposed on the opposite side of the crimping protrusion 30A from the magnet insertion hole 26, and has a substantially U-shape with the magnet insertion hole 26 side open. A similar spring portion 34 is formed in the second core piece 22B, with the phase shifted in the circumferential direction of each core piece 22 relative to the spring portion 34 of the first core piece 22A. As shown in FIG. 12 , in the second core piece 22B, a crimping protrusion 30B is formed at a location where the crimping protrusion A of the first core piece 22A overlaps, without the spring portion 34 formed adjacent thereto. As a result, the spring portions 34 of the core laminations 22A and 22B stacked adjacently above and below are arranged so as not to overlap in the thickness direction of the core laminations 22.

[0073] In the fourth modified example, the rotor core 12 is manufactured by alternately stacking first core laminations 22A, a portion of which is shown in FIG. 13, and second core laminations 22B, a portion of which is shown in FIG. 14. In this fourth modified example, an elliptical spring portion 36 is formed adjacent to the crimping protrusion 30A in the first core laminations 22A. The crimping protrusion 30A is formed inside this spring portion 36. The second core laminations 22B have similar spring portions 36 formed in phase with the spring portions 36 of the first core laminations 22A in the circumferential direction of each core lamination 22. As shown in FIG. 14, in the second core laminations 22B, crimping protrusions 30B are formed at locations where the crimping protrusions A of the first core laminations 22A overlap, with no spring portions 36 formed adjacent to them. As a result, the spring portions 36 of the core laminations 22A and 22B stacked adjacently above and below are arranged so as not to overlap in the thickness direction of the core laminations 22.

[0074] In the fifth modified example, the rotor core 12 is manufactured by alternately stacking first core pieces 22A, a portion of which is shown in FIG. 15, and second core pieces 22B, a portion of which is shown in FIG. 16, one above the other. In this fifth modified example, a substantially U-shaped spring portion 34 is formed in the first core piece 22A adjacent to the crimping protrusion 30. This spring portion 34 is disposed on the opposite side of the crimping protrusion 30 from the magnet insertion hole 26, and has a substantially U-shape with the magnet insertion hole 26 side open. A substantially U-shaped spring portion 38 is formed in the second core piece 22B adjacent to the crimping protrusion 30. This spring portion 38 is disposed on the magnet insertion hole 26 side from the crimping protrusion 30, and has a substantially U-shape with the opposite side of the magnet insertion hole 26 open. That is, the spring portion 34 formed on the first core piece 22A and the spring portion 38 formed on the second core piece 22B are arranged in opposite directions via the crimping protrusion 30. As a result, the spring portions 34, 38 of the core pieces 22A, 22B stacked adjacently one above the other are arranged so as not to overlap in the thickness direction of each core piece 22.

[0075] In the sixth modified example, the rotor core 12 is manufactured by alternately stacking first core laminations 22A, a portion of which is shown in FIG. 17, and second core laminations 22B, a portion of which is shown in FIG. 18. In this sixth modified example, a pair of circular spring portions 32 is formed adjacent to the crimping protrusion 30 in the first core laminations 22A. Similarly, a pair of circular spring portions 32 is formed adjacent to the crimping protrusion 30 in the second core laminations 22B. The pair of spring portions 32 formed in the first core laminations 22A and the pair of spring portions 32 formed in the second core laminations 22B are shifted from each other in the radial direction of the core laminations 22A and 22B. The pair of spring portions 32 formed in the first core laminations 22A and the pair of spring portions 32 formed in the second core laminations 22B are shifted from each other in the radial direction of the core laminations 22A and 22B alternately. As a result, the spring portions 32 of the core laminations 22A and 22B stacked adjacently above and below are arranged so as not to overlap in the thickness direction of the core laminations 22.

[0076] Various modified examples of spring portions formed in the rotor core will be described below with reference to FIGS. 19 to 25. Note that arrows X, Y, and Z, as appropriate, shown in FIGS. 19 to 25, indicate the circumferential direction, radial direction, and axial direction of the rotor core 12, respectively. In a seventh modified example shown in FIG. 19, the spring portion 40 is formed in an oval shape with its longitudinal direction extending in the radial direction of the rotor core 12. In an eighth modified example shown in FIG. 20, the spring portion 42 is formed in an elliptical shape with its longitudinal direction extending in the radial direction of the rotor core 12. In a ninth modified example shown in FIG. 21, the spring portion 44 is formed in a circular shape, and the crimping protrusion 30 is disposed inside the spring portion 44. In a tenth modified example shown in FIG. 22, the spring portion 46 is formed in a semicircular shape in side view (as viewed from the direction along the top and bottom surfaces of the core piece 22). In an eleventh modified example shown in FIG. 23, the spring portion 48 is formed in a substantially semi-elliptical shape in side view. In a twelfth modified example shown in Fig. 24, the spring portion 50 is formed in a trapezoidal shape when viewed from the side. In a thirteenth modified example shown in Fig. 25, the cross section of the spring portion 52 is formed in a cantilever shape. The shape of the spring portion can be changed as appropriate in addition to those shown in Figs. 19 to 25. Furthermore, the spring portions 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, and 52 may be combined.

[0077] While the present invention has been described above with reference to embodiments and various modifications, the present invention can be embodied in various modifications without departing from the spirit and scope of the present invention. Furthermore, the scope of the present invention is not limited to the above-described embodiments and various modifications. For example, the spring portions formed on adjacent core pieces stacked vertically may be arranged offset from one another in the thickness direction of the core pieces so as not to overlap, and their arrangement can be changed as appropriate. [Explanation of symbols]

[0078] 10 rotors 12 rotor core 14 Rotation axis 18 Through holes 22 Core piece 28 Caulking recess 30 Crimping protrusion 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52 Spring part

Claims

1. a rotor core made up of a plurality of core pieces stacked together by crimping a plurality of crimping recesses formed on the upper surface of each core piece and a plurality of crimping protrusions formed on the lower surface of each core piece; a rotating shaft inserted into a through hole formed in an axial center portion of the rotor core; A method for manufacturing a rotor comprising: a molding step of molding the core pieces while forming elastically deformable spring portions adjacent to at least some of the crimping protrusions or crimping recesses in at least some of the core pieces; a temporary assembly process of stacking the core pieces while crimping the plurality of crimping recesses and the plurality of crimping protrusions at positions shallower than normal crimping positions by the elastic force of the spring portion, thereby temporarily assembling the rotor core; an insertion process of inserting the rotating shaft into the through hole of the rotor core after the temporary assembly process; a fixing step of pressing the rotor core after the insertion step in the axial direction against the elastic force of the spring portion to crimp the plurality of crimping recesses and the plurality of crimping protrusions to the normal crimping positions; A method for manufacturing a rotor having the above structure.

2. The method for manufacturing a rotor according to claim 1 , wherein the pair of spring portions is formed so as to be point symmetrical with respect to the center of the at least one crimping protrusion.

3. 3. The method for manufacturing a rotor according to claim 1, wherein at least some of the crimping protrusions are formed in a rectangular shape, and the spring portions are formed on both sides of the at least some of the crimping protrusions in the longitudinal direction.

4. A method for manufacturing a rotor as described in any one of claims 1 to 3, wherein when a set of n adjacent core pieces is made, the number of crimping protrusions formed on each of the core pieces is a multiple of n, and in each of the core pieces, the spring portions are formed next to the number of crimping protrusions equal to the number of crimping protrusions divided by n, and when the set of core pieces is viewed from the axial direction, the spring portions are positioned next to all of the crimping protrusions.

5. A method for manufacturing a rotor as described in any one of claims 1 to 3, wherein when two adjacent core pieces are combined into a set, the number of crimping protrusions formed on each core piece is a multiple of 2, and in each core piece, the spring portions are formed next to the number of crimping protrusions equal to the number of crimping protrusions divided by 2, and when the set of core pieces is viewed from the axial direction, the spring portions are positioned next to all of the crimping protrusions.

6. 6. The method for manufacturing a rotor according to claim 4, wherein the spring portions are formed adjacent to a plurality of the crimping protrusions that are continuously arranged in the circumferential direction of the core piece.

7. a rotor core made up of a plurality of core pieces stacked together by crimping a plurality of crimping recesses formed on the upper surface of each core piece and a plurality of crimping protrusions formed on the lower surface of each core piece; a rotating shaft inserted into a through hole formed in an axial center portion of the rotor core; A rotor comprising: an elastically deformable spring portion is formed adjacent to at least some of the crimping protrusions in at least some of the core pieces, The rotor has the plurality of crimping recesses and the plurality of crimping protrusions crimped together with the spring portion elastically pressed in the axial direction of the rotor core.

8. 8. The rotor according to claim 7, wherein a pair of the spring portions are formed so as to be point symmetrical with respect to the center of the at least one crimped protrusion.

9. 9. The rotor according to claim 7, wherein the crimping projections are rectangular, and the spring portions are formed on both sides of at least some of the crimping projections in the longitudinal direction.

10. A rotor as described in any one of claims 7 to 9, wherein when a set of n adjacent core pieces is made up of the core pieces, the number of crimping protrusions formed on each of the core pieces is a multiple of n, and in each of the core pieces, the spring portions are formed next to the number of crimping protrusions equal to the number of crimping protrusions divided by n, and when the set of core pieces is viewed from the axial direction, the spring portions are arranged next to all of the crimping protrusions.

11. A rotor as described in any one of claims 7 to 9, wherein when two adjacent core pieces are considered as a set, the number of crimping protrusions formed on each of the core pieces is a multiple of 2, and in each of the core pieces, the spring portions are formed next to the number of crimping protrusions equal to the number of crimping protrusions divided by 2, and when the set of core pieces is viewed from the axial direction, the spring portions are arranged next to all of the crimping protrusions.

12. 12. The rotor according to claim 10, wherein the spring portions are formed adjacent to a plurality of the crimping protrusions that are continuously arranged in the circumferential direction of the core piece.

13. A rotor core made of a plurality of core pieces stacked by crimping a plurality of crimping recesses formed on the upper surface of each core piece and a plurality of crimping protrusions formed on the lower surface of each core piece, an elastically deformable spring portion is formed adjacent to at least some of the crimping protrusions in at least some of the core pieces, The rotor core is stacked such that the plurality of crimping recesses and the plurality of crimping protrusions are crimped by the spring portion at positions shallower than normal crimping positions.

14. The rotor core according to claim 13 , wherein the spring portions are arranged so as to be point symmetrical with respect to a center of the at least some of the crimping protrusions.

15. 15. The rotor core according to claim 13, wherein the crimping protrusions are rectangular, and the spring portions are disposed on both sides of at least some of the crimping protrusions in the longitudinal direction.

16. A rotor core as described in any one of claims 13 to 15, wherein when n adjacent core pieces are considered as a set, the number of crimping protrusions formed on each of the core pieces is a multiple of n, and in each of the core pieces, the spring portions are formed next to the number of crimping protrusions equal to the number of crimping protrusions divided by n, and when the set of core pieces is viewed from the axial direction, the spring portions are arranged next to all of the crimping protrusions.

17. A rotor core according to any one of claims 13 to 15, wherein when two adjacent core pieces are considered as a set, the number of crimping protrusions formed on each of the core pieces is a multiple of 2, and in each of the core pieces, the spring portions are formed next to the number of crimping protrusions equal to the number of crimping protrusions divided by 2, and when the set of core pieces is viewed from the axial direction, the spring portions are arranged next to all of the crimping protrusions.

18. 18. The rotor core according to claim 16, wherein the spring portions are formed adjacent to a plurality of the crimping protrusions that are continuously arranged in the circumferential direction of the core pieces.

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