CN106849535B

CN106849535B - Laminated iron core and manufacturing method thereof

Info

Publication number: CN106849535B
Application number: CN201611021410.XA
Authority: CN
Inventors: 饭田忠
Original assignee: Mitsui High Tec Inc
Current assignee: Mitsui High Tec Inc
Priority date: 2015-11-12
Filing date: 2016-11-09
Publication date: 2020-03-10
Anticipated expiration: 2036-11-09
Also published as: JP2017093191A; CN106849535A; JP6630123B2

Abstract

The method for manufacturing a laminated core of the present invention includes: (A) a step of supplying the processed plate to a metal mold; (B) a step of forming a plurality of magnet housing regions arranged at a predetermined interval in a circumferential direction by punching a plate to be processed with a die, and forming a main body portion as a passage of magnetic flux sandwiched between the magnet housing regions and a connecting portion having a narrower circumferential width than the main body portion; (C) a step of subjecting a corresponding region, which is a region corresponding to the connection portion, to crushing processing by a die, thereby work-hardening the corresponding region; (D) and a step of stacking a plurality of processed bodies obtained from the processed plates and fastening the stacked bodies to obtain a stacked core.

Description

Laminated iron core and manufacturing method thereof

Technical Field

The present invention relates to a laminated core constituting a rotor and a method for manufacturing the same.

Background

The laminated core is a component of the motor. A plurality of electromagnetic steel sheets (processed bodies) processed into a predetermined shape are laminated and fastened to form a laminated iron core. The motor includes a rotor (rotor) and a stator (stator) each formed of a laminated core, and is completed through a process of mounting a main shaft on the rotor, a process of winding a coil on the stator, and the like. The laminated core constituting the rotor has a plurality of poles. Each pole has one or more permanent magnets. These permanent magnets are accommodated in magnet accommodation regions (slots) provided in the laminated iron core. A motor having a rotor of this structure is called an IMP (internal permanent Magnet) motor.

As a rotor including a laminated core having magnet housing regions, there is known a rotor in which a plurality of magnet housing regions are arranged at predetermined intervals in a circumferential direction and a fan-shaped main body portion is formed between adjacent magnet housing regions, the rotor being laminated (see, for example, japanese patent laid-open No. 2001 and 37121). As a method of manufacturing a laminated core constituting a rotor, there is known a method including: a step of supplying an electromagnetic steel sheet (a work-piece sheet) to a progressive die (sequential delivery り au type); a step of manufacturing a processed body having a predetermined shape by punching in a progressive die; and a step of laminating the plurality of processed bodies to obtain a laminated core (see, for example, japanese patent laid-open No. 2003-211238).

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2001-37121

Patent document 2: japanese patent laid-open publication No. 2003-211238

Disclosure of Invention

Technical problem to be solved

When a worked body is obtained by punching, residual stress in the worked body due to a punching load becomes a problem. The residual stress may cause deformation of the laminated core. When a machined body in which a plurality of magnet housing regions are arranged in the circumferential direction is obtained by punching as described in japanese patent laid-open No. 2001-37121, the residual stress due to the punching load tends to increase because the region where punching is performed increases. In particular, when such residual stress exists in a portion having a weak strength, it causes deformation of the laminated core.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a laminated core in which deformation due to residual stress is suppressed, and a method for manufacturing the same.

(II) technical scheme

A method for manufacturing a laminated core according to an aspect of the present invention includes: (A) a step of supplying the processed plate to a metal mold; (B) a step of forming a plurality of magnet housing regions arranged at a predetermined interval in a circumferential direction by punching the plate to be processed by the die, and forming a main body portion as a passage of magnetic flux sandwiched between the magnet housing regions and a connecting portion having a narrower width in the circumferential direction than the main body portion; (C) a step of subjecting a corresponding region, which is a region corresponding to the coupling portion, to crushing processing by the mold to thereby work-harden the corresponding region; (D) and (C) laminating a plurality of processed bodies obtained from the processed plate by performing the steps (B) and (C), and fastening the laminated bodies to obtain a laminated core.

In the method for manufacturing a laminated core, in the step (C), the region corresponding to the connection portion is work-hardened by crushing. The connecting portion has a small circumferential width and a small area, and therefore has a low strength and is likely to be deformed by residual stress due to a punching load. In this regard, in the method of manufacturing a laminated core, since the region corresponding to the connection portion is work-hardened, deformation of the connection portion due to residual stress can be suppressed. Thus, according to the method for manufacturing a laminated core, in the laminated core of the rotor, which is a laminated body in which the processed bodies in which the plurality of magnet housing regions are arranged, deformation due to residual stress can be suppressed.

(C) The step may include a step of crushing the entire corresponding region by the mold. As a result, the entire region corresponding to the coupling portion is work-hardened, and therefore the work-hardened region becomes large, and deformation of the coupling portion can be suppressed more effectively.

(C) The step may include a step of crushing only one side in the circumferential direction of the corresponding region by the mold. By crushing only one side, the one side is plastically deformed, and a force is generated in a direction opposite to the one side. Accordingly, for example, when a residual stress acts in the one-side direction, a force that cancels the residual stress is generated by the crushing process, and therefore, the deformation of the connection portion in the direction of the residual stress can be corrected.

In the step (B), the region of each magnet housing region in contact with the corresponding region may be formed in a plurality of steps so that regions of the magnet housing regions adjacent in the circumferential direction in contact with the corresponding region are not formed at the same time, and the step (C) may include a step of crushing, by a mold, only the magnet housing region side of the corresponding region in which the region in contact with the corresponding region is formed later. There is a residual stress based on a punching load when the magnet housing area is formed on the coupling portion. More specifically, there is a residual stress in the direction of the punched magnet housing area in the connecting portion. Here, when the region of the plurality of magnet housing regions that is in contact with the corresponding region is formed in a plurality of steps, the punching load acting on the corresponding region during punching increases as the subsequent steps proceed. That is, the area of the workpiece plate receiving the punching load becomes smaller as the subsequent process proceeds, and therefore a larger punching load acts on the corresponding area. Therefore, the connecting portion has a larger residual stress in the direction of the magnet housing area punched out in a later process. In this regard, by performing crushing processing on the magnet housing region side of the corresponding region, on which the region that comes into contact with the corresponding region is formed later, it is possible to effectively correct deformation of the connection portion in a direction in which a residual stress acts more largely.

(C) The step may include a step of performing crushing processing with a mold only on the magnet housing region side of the corresponding region where the region in contact with the corresponding region is formed first. This makes it possible to generate a force that cancels the residual stress generated by punching the magnet housing area in the previous step. This makes it possible to appropriately correct not only the deformation of the connecting portion due to the punching in the subsequent step but also the deformation of the connecting portion due to the punching in the previous step.

A laminated core according to an aspect of the present invention includes: a cylindrical portion; a plurality of body portions formed at predetermined intervals in a circumferential direction on a radially outer side of the cylindrical portion, and serving as magnetic flux paths; a connecting portion formed to connect the cylindrical portion and the body portion, and having a width in a circumferential direction smaller than that of the body portion; and a magnet housing space formed between the body portions adjacent to each other, wherein at least a part of the coupling portion is work-hardened.

(III) advantageous effects

According to one embodiment of the present invention, deformation due to residual stress can be suppressed.

Drawings

Fig. 1 is a perspective view showing an example of a laminated core constituting a rotor.

Fig. 2 is a plan view showing a machined body included in the laminated core shown in fig. 1.

Fig. 3 is an enlarged perspective view of the region OE shown in fig. 2.

Fig. 4 is a schematic view showing an example of the punching apparatus.

Fig. 5 (a) to (f) are plan views showing the entire layout (layout) of the punching process.

Fig. 6 (a) and (b) are enlarged plan views showing fig. 5 (a) and (b) in the layout shown in fig. 5.

Fig. 7 (a) and (b) are enlarged plan views showing fig. 5 (c) and (d) in the layout shown in fig. 5.

Fig. 8 (a) and (b) are enlarged plan views showing fig. 5 (e) and (f) in the layout shown in fig. 5.

Fig. 9 (a) is an enlarged plan view showing the region SE1 shown in fig. 7 (b), and fig. 9 (b) is an enlarged plan view showing the region SE2 shown in fig. 8 (a).

Fig. 10 is an enlarged perspective view of a coupling portion of a modification.

Detailed Description

Embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, the same elements or elements having the same function are denoted by the same reference numerals, and redundant description thereof will be omitted.

< laminated core and processed body >

Fig. 1 is a perspective view of a laminated core R constituting a rotor. The laminated core R has a substantially cylindrical shape, and an opening Ra at the center is for mounting a spindle (not shown). A protruding key (not shown) may be provided on the inner circumferential surface Rb constituting the opening Ra as a structure for attaching the main shaft.

The laminated core R is configured by laminating a plurality of processed bodies PB (see fig. 2). Fig. 2 is a plan view showing a processed body PB included in the laminated core R shown in fig. 1. The processed body PB is obtained from an electromagnetic steel sheet (a processed sheet) by punching with a die described later. The processed body PB includes: an annular ring portion 111; a plurality of magnet housing regions 112 arranged at predetermined intervals in the circumferential direction around the annular portion 111; a main body portion 113 that is a passage of magnetic flux sandwiched between the plurality of magnet housing regions 112, and a connecting portion 115 that is narrower in width in the circumferential direction than the main body portion; a convex portion 114 extending from the outer peripheral surface PBc of the annular portion 111 toward the magnet housing area 112.

The magnet housing areas 112 are, for example, eight in the circumferential direction at equal intervals. Each magnet housing area 112 has: an inner region 112b in contact with the annular portion 111, and an outer region 112c continuous with the inner region 112b and located radially outward of the inner region 112 b. The inner region 112b is, for example, half or more of the entire magnet housing region 112. The inner region 112b is formed earlier than the outer region 112c (to be described later). The inner regions 112b of the magnet housing regions 112 adjacent to each other in the circumferential direction are not formed at the same time. That is, first, the first inner region 112x, which is the inner region 112b of a part of the magnet housing regions 112 that are not adjacent to each other, is formed, and then the second inner region 112y, which is the inner region 112b of the remaining magnet housing regions 112 that are not adjacent to each other, is formed (to be described later). Therefore, the first inner regions 112x and the second inner regions 112y are alternately arranged in the circumferential direction.

The main body portion 113 is formed in a substantially fan shape in a top view. The main body portion 113 has

engagement portions

113a, 113b on the radially outer side and the radially inner side. The laminated core R is configured by fastening the processed bodies PB overlapped in the vertical direction to each other by caulking (caulking) at the joining

portions

113a, 113 b. That is, each of the worked bodies PB has the joining

portions

113a and 113b having a concave portion formed on the front surface and a convex portion formed on the back surface. The upper and lower processed bodies are fastened by the engagement of the back surface (convex portion) of the upper processed body PB with the front surface (concave portion) of the lower processed body PB. In order to prevent the plurality of laminated cores R from being fastened to each other, the

joint portions

113a and 113b of the processed body PB located at the lowermost portion of the laminated body are formed as through holes, instead of the convex portions and the concave portions.

Although the laminated core R is described as an example in which the processed bodies PB are laminated and fastened by caulking, the processed bodies PB may be fastened and connected by any method. For example, the plurality of worked bodies PB may be fastened to each other by welding, bonding, or a resin material. From the viewpoint of cost and work efficiency, caulking and welding have been widely used. On the other hand, when high torque and low core loss of the motor are prioritized, a resin material or an adhesive may be used instead of caulking or welding. In addition, the machined bodies PB may be provided with temporary caulking portions (temporary caulking portions) to fasten the machined bodies PB to each other, and then the temporary caulking portions may be finally removed from the laminated body to obtain the laminated core R. The "temporary caulking portion" refers to a caulking portion (swaged area) that is used when a plurality of processed bodies manufactured by punching are temporarily integrated and is removed in a process of manufacturing a product (laminated iron core).

Further, an outer convex edge 113e protruding toward the adjacent magnet housing area 112 is provided radially outward of the main body portion 113.

The coupling portion 115 extends from the outer peripheral surface PBc of the annular portion 111 toward the body portion 113, and couples (connects) the annular portion 111 and the body portion 113 between the plurality of magnet housing regions 112.

Fig. 3 is an enlarged perspective view of the region OE shown in fig. 2. As shown in fig. 3, the coupling portion 115 is formed with

deformation portions

115a and 115b which are plastically deformed by crushing processing using a die described later and are work-hardened (strain-hardened). The deformation portion 115a is formed on the entire area of the coupling portion 115. In addition, the deformation portion 115b is formed only on one side in the circumferential direction of the coupling portion 115. More specifically, the deformed portion 115b is formed on the side of the joining portion 115 that meets the second inner region 112 y. In addition, the deformation portions 115b are formed at the center portion in the radial direction of the coupling portion 115, not at both ends in the radial direction.

The processed body PB is laminated to form a laminated core R shown in fig. 1. The laminated core R includes: a cylindrical portion 11 surrounding a main shaft (rotation shaft); a plurality of magnet housing spaces 12 formed at predetermined intervals in the circumferential direction on the outer side in the radial direction of the cylindrical portion 11; and a body portion 13 serving as a passage for magnetic flux formed between the magnet housing spaces 12 adjacent to each other. The magnet housing space 12 is a space for housing one or more permanent magnets (for example, sintered magnets such as neodymium magnets, bonded magnets), and is a space between the side surfaces 13c of the two adjacent main body portions 13. The cylindrical portion 11, the magnet housing space 12, and the main body portion 13 are formed by laminating an annular portion 111, a magnet housing area 112, and a main body portion 113 of the processed body PB, respectively.

Radially outward of the main body 13, an outer flange portion 13e protruding toward the adjacent magnet housing space 12 is provided from the upper surface to the lower surface of the main body 13. The size and shape of the outer flange portion 13e are appropriately determined from the viewpoint of appropriately fixing the magnet (not shown) in the magnet housing space 12, the viewpoint of suppressing the leakage magnetic flux, and the like. The outer flange portion 13e is formed by laminating the outer flanges 113 e.

The laminated core R includes: a convex portion 14 extending from the outer peripheral surface Rc of the cylindrical portion 11 toward the magnet housing space 12; and a connection portion 15 extending from the outer peripheral surface Rc toward the body portion 13. The convex portion 14 and the coupling portion 15 are formed by laminating the convex portion 114 and the coupling portion 115 of the processed body PB. The coupling portion 15 is formed between the magnet housing spaces 12 adjacent to each other, has a smaller circumferential width than the body portion 13, and is work-hardened in a region corresponding to the above-described

deformed portions

115a and 115 b.

< punching device >

Fig. 4 is a schematic diagram showing an example of a punching apparatus for manufacturing a processed body PB constituting a laminated core R by punching. The punching apparatus 100 shown in the figure includes: an uncoiler 110 provided with a layer coil body C; a feeding device 130 for an electromagnetic steel sheet (hereinafter referred to as "sheet to be processed W") drawn from the layered body C; a progressive die 140 (metal die) for punching the workpiece W; and a pressing machine 120 that operates the progressive die 140.

The unwinder 110 rotatably holds the layer roll C. The length of the plate W to be processed constituting the laminate roll C is, for example, 500 to 10000 m. The thickness of the plate W to be processed constituting the layer wound body C may be about 0.1 to 0.5mm, and may be about 0.1 to 0.3mm from the viewpoint of achieving more excellent magnetic characteristics of the laminated core R. The width of the plate W to be processed is preferably about 50 to 500 mm.

The feeding device 130 includes a pair of

rollers

130a and 130b for sandwiching the workpiece W from above and below. The workpiece W is introduced into the progressive die 140 by the feeder 130. The progressive die 140 is used to continuously perform punching, bending, shearing, bending, push back (push back), crushing, and the like on the work sheet W.

< method for manufacturing laminated iron core >

Next, a method for manufacturing the laminated core R will be described. The laminated core R is manufactured through a process of manufacturing the processed bodies PB (the following process (a), (B), and (C)) and a process of manufacturing the laminated core R from the plurality of processed bodies PB (the following process (D)). More specifically, the method for manufacturing the laminated core R includes the following steps.

(A) And a step of supplying the processed plate W to the progressive die 140.

(B) The method includes a step of punching the workpiece plate W by the progressive die 140 to form a plurality of magnet housing areas 112 arranged at a predetermined interval in the circumferential direction, and also to form a main body portion 113 that is a passage of magnetic flux sandwiched between the magnet housing areas 112 and a connecting portion 115 having a narrower circumferential width than the main body portion 113.

(C) And a step of subjecting the corresponding region 115z, which is a region corresponding to the connection portion 115, to a crushing process using the progressive die 140, thereby work-hardening the corresponding region 115 z.

(D) And (C) stacking a plurality of processed bodies PB obtained from the processed plate W by performing the steps (B) and (C), and fastening them to obtain the laminated core R.

First, a layered wound body C of an electrical steel sheet is prepared and mounted on the uncoiler 110. The electromagnetic steel sheet (the work sheet W) pulled out from the layered product C is supplied to the progressive die 140 (step a).

The progressive die 140 performs punching on the workpiece W to continuously produce a processed body PB in which the magnet housing area 112, the main body portion 113, and the coupling portion 115 are formed (step B). In the present embodiment, in the middle of the step (B), the corresponding region 115z, which is a region corresponding to the coupling portion 115 sandwiched between the magnet housing regions 112, of the regions formed as the coupling portions 115 later is subjected to the press working by the progressive die 140, and the corresponding region 115z is plastically deformed and is work-hardened (step (C)). More specifically, in the step (C), the entire region corresponding to the region 115z is crushed by the progressive die 140 to form the deformed portion 115 a. Further, in the step (C), only one side in the circumferential direction of the corresponding region 115z is further crushed by the progressive die 140 to form the deformed portion 115 b.

The following describes the steps (B) and (C) with reference to fig. 5 to 8. Fig. 5 (a) to (f) are plan views showing the entire layout of the punching process. Fig. 6 (a) and (b) are enlarged plan views showing fig. 5 (a) and (b) in the layout shown in fig. 5. Fig. 7 (a) and (b) are enlarged plan views showing fig. 5 (c) and (d) in the layout shown in fig. 5. Fig. 8 (a) and (b) are enlarged plan views showing fig. 5 (e) and (f) in the layout shown in fig. 5. The pattern of the punching process is not limited to the pattern shown in fig. 5, and a step for balancing the pressure load may be added, for example, a step for forming a temporary caulking may be added. (B) The step (C) is composed of the step C1 and the step C2, which will be described later.

The step B1 is a step of forming a guide hole P in the workpiece W (see fig. 5a and 6 a). The guide hole P is used for positioning the processed board W in the progressive die 140.

The B2 step is a step of forming a first inner region 112x formed in advance in the inner region 112B of the plurality of magnet housing regions 112 (see fig. 5 (B) and 6 (B)). In the B2 step, of the magnet housing areas 112 formed at eight places, the inner side areas 112B of the magnet housing areas 112 at four places not adjacent to each other in the circumferential direction, that is, the first inner side areas 112x, are formed.

The B3 step is a step of forming a second inner region 112y formed subsequent to the first inner region 112x in the inner region 112B of the plurality of magnet housing regions 112 (see fig. 5c and 7 a). In the B3 step, of the magnet housing areas 112 formed at eight places, the second inner area 112y, which is the inner area 112B of the magnet housing area 112, is formed at four places (four places other than the magnet housing area 112 including the above-described first inner area 112 x) that are not adjacent to each other in the circumferential direction.

In this way, in the steps of forming the inner regions 112B (steps B2 and B3), the inner regions 112B of the magnet housing regions 112 adjacent in the circumferential direction (regions in contact with the corresponding region 115z in the magnet housing regions 112) are formed at different times, and thus the first inner region 112x and the second inner region 112y are formed in a plurality of steps, specifically, in two steps.

By performing the B2 step and the B3 step, the corresponding region 115z which becomes the coupling portion 115 after being formed between the magnet housing regions 112 adjacent in the circumferential direction (more specifically, between the first inner region 112x and the second inner region 112y) (see fig. 7 (a)). The circumferential width of the corresponding region 115z is the same as that of the connecting portion 115.

The step B4 is a step of forming a recess (a projection when viewed from the back) or a through hole in the processed body PB at a position corresponding to the joining portions 113a and 113B of the main body portion 113 (see fig. 5 (d) and 7 (B)). That is, in the step B4, when the processed body PB other than the processed body PB positioned at the lowermost portion of the laminated core R is manufactured, the concave portions are formed at the positions corresponding to the joint portions 113a and 113B by bending, and when the processed body PB positioned at the lowermost portion of the laminated core R is manufactured, the punched holes are formed at the positions corresponding to the joint portions 113a and 113B by punching.

The C1 step is performed simultaneously with the B4 step described above. The step C1 is a step of crushing the entire region corresponding to the region 115 z. In step C1, the progressive die 140 is crushed by a stripper (not shown) attached to the lower surface of the upper die (punch). The stripper is used for sandwiching a workpiece W between the stripper and a lower die (die). In the present embodiment, the punch plate is provided with a projection (not shown), and the corresponding region 115z is pressed from above by the projection, and the corresponding region 115z is further subjected to crushing processing. That is, in step C1, the entire region corresponding to the region 115z is pressed by the projection of the stripper, and the entire region is further subjected to crushing processing. The crushing processing in the step C1 may be performed on all (eight) corresponding regions 115z between the magnet housing regions 112, or may be performed on only a part (for example, four) corresponding regions 115 z.

Fig. 9 (a) is an enlarged view of the region SE1 shown in fig. 7 (b). As shown in fig. 9 (a), when the entire region corresponding to the region 115z is subjected to the crushing process in the step C1, a deformed portion 115a which is plastically deformed and work-hardened is formed in the entire region corresponding to the region 115 z. The amount of dent of the deformed part 115a, i.e., the amount of crush by the crushing process in the step C1, is about 10 to 50 μm, for example about 20 to 30 μm.

The B5 step is a step of forming the central region 111a by punching the inside of the annular portion 111 (see fig. 5 (e) and 8 (a)).

The C2 step is performed simultaneously with the B5 step described above. The step C2 is a step of crushing only one side in the circumferential direction of the corresponding region 115 z. In the C2 step, the punch press is crushed by the projections (not shown) of the stripper plate attached to the lower surface of the upper die (punch) in the same manner as in the C1 step. That is, in the step C2, one side of the region 115z corresponding to the projection of the stripper is pressed in the circumferential direction, and the one side region is subjected to crushing processing. More specifically, in the step C2, only the side of the corresponding region 115z that contacts the second inner region 112y (the side of the magnet housing region 112 where the inner region 112b is formed later) is subjected to the crushing process. The crushing processing in the step C2 may be performed on all (eight) corresponding regions 115z between the magnet housing regions 112, or may be performed on only a part (for example, four) corresponding regions 115 z.

Fig. 9 (b) is an enlarged view of the region SE2 shown in fig. 8 (a). As shown in fig. 9 (b), when only one side (the side contacting the second inner region 112y) in the circumferential direction of the corresponding region 115z is subjected to the crushing process in the step C2, the deformed portion 115b that is plastically deformed and work-hardened is formed only on the side contacting the second inner region 112y in the corresponding region 115 z. That is, in the corresponding region 115z, the deformed portion 115a is formed over the entire region, and the deformed portion 115b is further formed on the side contacting the second inner region 112 y. The amount of dent of the deformed part 115b, i.e., the crushing amount in the crushing process in the step C2, is about 10 to 50 μm, for example about 30 to 40 μm.

The B6 step is a step of forming an outer region 112c formed next to the inner region 112B in the magnet housing region 112 (see fig. 5 (f) and 8 (B)). In step B6, the outer regions 112c of the plurality of magnet housing regions 112 are collectively formed. Specifically, in the B6 step, an area that is radially outward of the magnet housing area 112 with respect to the inner area 112B is formed as the outer area 112 c.

In step B6, the outer region 112c is formed so that a part of the outer region 112c overlaps the inner region 112B. That is, the workpiece sheet W is punched so that a portion through which the punch passes in punching the inner region 112B (specifically, the first inner region 112x or the second inner region 112y) in the B2 step or the B3 step overlaps with a portion through which the punch passes in punching the outer region 112c in the B6 step. Thus, the inner region 112b and the outer region 112c have an overlapping region where the regions overlap each other.

When the punching accuracy of the progressive die 140 is lowered due to a lowering in the feeding position accuracy of the work W with respect to the progressive die 140 or the assembling accuracy of the progressive die 140, the inner region 112b and the outer region 112c may not become continuous punching regions, resulting in the occurrence of burrs or the problem of cutting residue. In this regard, by partially overlapping the inner region 112b and the outer region 112c, even when the punching accuracy is lowered, the inner region 112b and the outer region 112c are easily made continuous, and the occurrence of burrs and the like can be suppressed.

In the overlapping region, the inner region 112b may be formed so that a notch (not shown) is formed in the side 113c of the adjacent main body portion 113. By forming the cut in the body portion 113, the region where the inner region 112b overlaps the outer region 112c can be further expanded. Thus, even when the punching accuracy is lowered, it is possible to reliably avoid the case where the inner region 112b and the outer region 112c are discontinuous punching regions, and it is possible to more favorably suppress the occurrence of burrs and the like.

In addition, in step B6, the region of the main body portion 113 is die-cut while forming the outer region 112c (see fig. 8 (B)). Thereby, the processed body PB formed with the annular portion 111, the magnet housing area 112, the body portion 113, and the connecting portion 115 is obtained.

Next, the processed bodies PB (see fig. 2) obtained from the plate W to be processed through the steps B1 to B6, C1, and C2 are stacked by a predetermined number of sheets, and are fastened by caulking to obtain the laminated core R ((D) step).

Next, the operational effects of the above-described method for manufacturing a laminated core will be described.

The method for manufacturing the laminated core R of the present embodiment includes: (A) a step of supplying the processed plate W to the progressive die 140; (B) a step of punching the workpiece W by the progressive die 140 to form a plurality of magnet housing areas 112 arranged at a predetermined interval in the circumferential direction, and to form a main body portion 113 that is a passage of magnetic flux sandwiched between the magnet housing areas 112 and a connecting portion 115 having a narrower circumferential width than the main body portion 113; (C) a step of subjecting a corresponding region 115z, which is a region corresponding to the connection portion 115, to a crushing process by using a progressive die 140, thereby work-hardening the corresponding region 115 z; (D) and (C) stacking a plurality of processed bodies PB obtained from the processed plate W by performing the steps (B) and (C), and fastening them to obtain the laminated core R.

In the method of manufacturing the laminated core R, in the step of generating work hardening, a region (corresponding region 115z) corresponding to the coupling portion 115 having a width narrower in the circumferential direction than the main body portion 113 is work hardened by crushing. The connecting portion 115 obtained by the punching process has a narrow width in the circumferential direction and a small area, and therefore has a low strength and is likely to be deformed by a residual stress due to a punching load. In this regard, in the method of manufacturing the laminated core R, since the corresponding region 115z is work-hardened, deformation of the connecting portion 115 due to residual stress can be suppressed. As described above, according to the method of manufacturing the laminated core R, in the laminated core R of the rotor, which is the laminated body in which the processed bodies PB in which the plurality of magnet housing regions 112 are arranged, deformation due to residual stress can be suppressed.

The step (C) includes a step of crushing the entire region corresponding to the region 115z by the progressive die 140 (step C1). Accordingly, since the entire region corresponding to the region 115z is work-hardened, the work-hardened region is increased, and the deformation of the coupling portion 115 can be suppressed more effectively.

The step (C) includes a step of crushing only one side of the corresponding region 115z in the circumferential direction by the progressive die 140 (step C2). By crushing only one side, the one side is plastically deformed, and a force is generated in a direction opposite to the one side. Accordingly, for example, when a residual stress acts in the one-side direction, a force that cancels the residual stress is generated by the crushing process, and therefore, the deformation of the coupling portion 115 in the direction of the residual stress can be corrected.

In the step (B) (more specifically, in the steps B2 and B3), the first inner region 112x and the second inner region 112y of each magnet housing region 112 are formed in a plurality of steps so that the inner regions 112B, which are regions of the circumferentially adjacent magnet housing regions 112 that are in contact with the corresponding region 115z, are not formed at the same time, and the step (C) includes a step of crushing only the second inner region 112y side (the magnet housing region 112 side in which the region in contact with the corresponding region 115z is formed later) of the corresponding region 115z by the progressive die 140.

There is a residual stress in the coupling portion 115 based on the blanking load when the magnet housing area 112 is formed. More specifically, there is a residual stress in the coupling portion 115 in the direction of the punched magnet housing area 112. Here, in the punching process, if the punching area in the narrow range is increased, the load applied to the progressive die 140 at the time of punching is increased, which is not preferable. Therefore, in the present embodiment, the inner regions 112B of the adjacent magnet housing regions 112 are formed in two steps (step B2 and step B3) so that the inner regions 112B are not formed at the same time. In this way, when the inner regions 112b of the plurality of magnet housing regions 112 are formed in a plurality of steps, the punching load acting on the corresponding region 115z during punching increases as the subsequent step (the step of forming the second inner region 112y) progresses. That is, the area of the workpiece plate W that receives the blanking load is smaller in the later steps, and therefore a larger blanking load acts on the corresponding area 115 z. Therefore, residual stress in the direction of the magnet housing area 112 (the direction of the second inner area 112y) punched in a later process is more greatly present in the coupling portion 115. In this regard, since a force in a direction opposite to the direction of the second inner region 112y is generated by crushing the second inner region 112y side in the corresponding region 115z, it is possible to effectively correct the deformation of the connecting portion 115 in a direction in which a larger residual stress acts.

The embodiments of the present invention have been described above, but the present invention is not limited to the above embodiments. For example, although the step (C) has been described as including the step of crushing only the second inner region 112y side on the corresponding region 115z (the magnet housing region 112 side where the region in contact with the corresponding region 115z is formed later) by the progressive die 140, the step (C) may include the step of crushing only the first inner region 112x side on the corresponding region 115z (the magnet housing region 112 side where the region in contact with the corresponding region 115z is formed first) by the progressive die 140. The crushing process is performed only on the first inner region 112x side, for example, simultaneously with the B2 step of forming the first inner region 112 x.

Fig. 10 is an enlarged perspective view of the coupling portion 115 according to a modification. As shown in fig. 10, by crushing the first inner region 112x side, a deformed portion 115c is formed on the connecting portion 115 only on the side contacting the first inner region 112x, which is plastically deformed and work-hardened. This can generate a force that cancels the residual stress caused by punching the magnet housing area 112 in the preceding step (the step of forming the first inner area 112 x) in the two steps of forming the inner area 112 b. This makes it possible to appropriately correct not only the deformation of the connecting portion 115 due to the punching in the subsequent step (step of forming the second inner region 112y), but also the deformation of the connecting portion 115 due to the punching in the previous step.

Although the example has been described in which the entire region corresponding to the region 115z is crushed in the C1 step, and then only one side of the region corresponding to the region 115z is crushed in the C2 step, the present invention is not limited to this, and the entire region corresponding to the region 115z may be crushed in a step subsequent to the crushing of only one side. In addition, only one of the crushing processing in the C1 step and the C2 step may be performed. That is, the crushing process may be performed only on the entire corresponding region 115z, or may be performed only on one side of the corresponding region 115 z.

Although the description has been given by taking as an example the case where the corresponding region 115z to be the connecting portion 115 is crushed after the punching process, the present invention is not limited to this, and for example, the connecting portion 115 may be crushed after the above-described B6 step (i.e., after the connecting portion 115 is formed). As described above, the "region corresponding to the connecting portion 115" in the embodiment includes not only the corresponding region 115z but also the connecting portion 115 itself.

Claims

1. A method of manufacturing a laminated core, comprising:

(A) a step of supplying the processed plate to a metal mold;

(B) a step of forming a plurality of magnet housing regions arranged at a predetermined interval in a circumferential direction by punching the plate to be processed by the die, and forming a main body portion as a passage of magnetic flux sandwiched between the magnet housing regions and a connecting portion having a width narrower in the circumferential direction than the main body portion;

(C) a step of subjecting a corresponding region, which is a region corresponding to the connection portion and belonging to the connection portion, to crushing processing by the metal mold, thereby work-hardening the corresponding region;

(D) and (C) laminating a plurality of processed bodies obtained from the processed plate by performing the step (B) and the step (C), and fastening the laminated bodies to obtain a laminated core.

2. The method of manufacturing a laminated core according to claim 1,

the step (C) includes a step of crushing the entire corresponding region by the mold.

3. The method of manufacturing a laminated core according to claim 1 or 2, wherein the step (C) includes a step of performing crushing processing on only one side in the circumferential direction of the corresponding region by the metal mold.

4. The method of manufacturing a laminated core according to claim 3,

in the step (B), the region of each magnet housing region that is in contact with the corresponding region is formed in a plurality of steps so that the regions of the magnet housing regions that are adjacent in the circumferential direction that are in contact with the corresponding region are not formed at the same time,

the step (C) includes a step of performing crushing processing by the mold only on the magnet housing region side of the corresponding region where a region in contact with the corresponding region is formed later.

5. The method of manufacturing a laminated core according to claim 4,

the step (C) includes a step of performing crushing processing by the mold only on the magnet housing region side of the corresponding region where a region in contact with the corresponding region is formed first.

6. A laminated core in which a plurality of processed bodies are laminated, comprising:

a cylindrical portion;

a plurality of body portions formed at predetermined intervals in a circumferential direction on a radially outer side of the cylindrical portion, and serving as magnetic flux paths;

a connecting portion formed to connect the cylindrical portion and the body portion, the connecting portion having a width in the circumferential direction smaller than that of the body portion;

a magnet housing space formed between the body portions adjacent to each other,

the coupling portion is work-hardened only on one side in the circumferential direction.