JP2010057221A - Rotary electric machine, its stator core, and method for manufacturing stator core - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive rotary electric machine and its stator core, which suppress a reduction in core loss resulting from the use of a cold rolled steel sheet while securing a sufficient welding strength, irrespective of the structure of a stator core which alternately laminates the cold rolled steel sheet formed on a smooth surface and a dull-finished electromagnetic steel sheet, and a method for manufacturing the stator core. <P>SOLUTION: The stator core 1 is structured by alternately laminating the electromagnetic steel sheet 9 and the cold rolled steel sheet 11 via an organic insulative film, and welding portions 6a, 6b, leading from one end in the laminating direction, to the other end, of the outer circumferential surface of a core back portion 2, are formed on the outer circumferential surface of the core back portion 2, causing the laminated electromagnetic steel sheet 9 and the cold rolled steel sheet 11 to be connected integrally. Then, the electromagnetic steel plate 9 is formed in a surface roughness of 0.5 μmHr m s or more on both surfaces and both surfaces of the electromagnetic steel plate 9 are covered with the organic insulating film, while the cold rolled steel sheet 11 is manufactured thinner in thickness than that of the electromagnetic steel plate 9, and is formed in a surface roughness of less than 0.5 μmHr m s on both surface. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a rotating electrical machine such as an AC generator for vehicles, a stator core applied to the rotating electrical machine, and a method for manufacturing the stator core, and more particularly, a structure of a stator core configured by welding and integrating laminated steel plates. And a manufacturing method thereof.

  A stator core in a conventional vehicle alternator has a rectangular parallelepiped shape by laminating a predetermined number of SPCC materials (cold rolled steel plates) punched into a predetermined shape by press forming, and laser welding the outer periphery of the SPCC material laminate. A laminated core is manufactured, a winding assembly is mounted on the laminated core, the laminated core with the winding assembly is rounded, both ends of the rounded laminated core are butted, and the butted portion is laser welded to form a cylindrical shape (See, for example, Patent Document 1).

  In the thing of this patent document 1, the insulating film is not coat | covered on the surface of the cold rolled steel plate. For this reason, the resistance between the cold-rolled steel sheets stacked is reduced, and the generation of eddy currents cannot be suppressed. In addition, when an annealing process is performed to recover and improve the decrease in magnetic properties during processing, a baking phenomenon occurs between cold-rolled steel sheets. Therefore, when an alternating magnetic field is applied, an eddy current flows through the burned portion, resulting in iron loss.

  Therefore, an electrical device in which a cold-rolled steel sheet not coated with an insulating coating and an electromagnetic steel sheet coated with insulating coating on both the front and back surfaces are punched into a predetermined shape, and a predetermined number of layers are alternately laminated, followed by heat treatment. A method of manufacturing an iron core has been proposed (see, for example, Patent Document 2). In the thing of this patent document 2, since the cold-rolled steel plate and the electromagnetic steel plate are insulated by the insulation film, even if an alternating magnetic field generate | occur | produces, generation | occurrence | production of an eddy current can be suppressed and an iron core can be suppressed. Energy loss due to heat generation at can be reduced. Further, since the insulating coating is present between the steel plates, when the laminate of the steel plates is annealed at a recrystallization temperature or higher, no baking phenomenon occurs between the steel plates, and the magnetic characteristics can be improved.

However, the insulating coating coated on the surface of the electromagnetic steel sheet contains an organic substance, and volatile gas is generated due to thermal decomposition of the organic substance when the laminate of the steel sheets is laser welded. This gas penetrates into the weld bead and is ejected as bubbles from the bead, creating a blow hole in the welded portion, and the welding strength is reduced. When this iron core is attached to the frame, the external load is applied to the frame, and the load applied to the welded portion of the iron core is small. However, when this iron core is applied to an AC generator for a vehicle, the iron core is not mounted on the frame, so an external load is directly applied to the iron core, and a large load is applied to the welded portion of the iron core. Therefore, if a blowhole is generated in the welded portion and the welding strength is reduced, there arises a problem that the iron core is damaged.
Furthermore, since cold-rolled steel sheets are inferior in magnetic properties (permeability and iron loss) to electromagnetic steel sheets, the use of cold-rolled steel sheets causes a problem that magnetic properties are lowered, and particularly iron loss is increased. .

  Therefore, the magnetic core is improved by laminating only the electromagnetic steel sheets that have a surface with a roughness of 0.5μmHr · m · s or more and the insulating coating is coated on both sides. Especially, while reducing iron loss, forming a gas passage gap between the laminated electrical steel sheets, dissipating volatile gas generated from the insulating coating during welding from the periphery of the weld through the gas passage gap, Generation | occurrence | production of the blowhole was suppressed in the welding part (for example, refer patent document 3). Furthermore, one surface is formed as a rough surface, the other surface is formed as a smooth surface, and an insulating steel sheet is coated on both surfaces or only one surface to form a stator core to form a magnetic core. In particular, iron loss is reduced and gaps between rough and smooth surfaces are formed between the laminated electrical steel sheets, and volatile gas generated from the insulating coating during welding passes through the gaps and around the welds. The occurrence of blow holes in the welded portion was suppressed (see, for example, Patent Document 4).

JP 2002-159151 A Japanese Patent Laid-Open No. 60-22447 Japanese Patent Publication No.49-6744 Japanese Patent Laid-Open No. 01-232705

  Thus, in the thing of patent document 3, 4, since the surface is formed in the rough surface and only the electromagnetic steel plate with which the insulating film was coat | covered is laminated | stacked, while being able to improve a magnetic characteristic, A decrease in weld strength due to the occurrence can be suppressed, and weldability can be improved. However, in the thing of patent document 3, 4, since only the expensive electromagnetic steel plate was used compared with the cold rolled steel plate, there existed a subject that cost reduction of a stator core could not be attained.

  In view of such a situation, the present applicant pays attention to the influence of the surface roughness and thickness of cold-rolled steel sheets and electromagnetic steel sheets on hysteresis loss and eddy current loss, which are individual components of iron loss. By optimizing the relationship between the surface roughness of the steel sheet and the plate thickness, the inventors have arrived at the idea that an increase in iron loss caused by using a cold-rolled steel plate can be suppressed, and the present invention has been invented.

  The present invention has been made to solve such a problem, and even if the cold rolled steel plate and the electromagnetic steel plate are alternately laminated, it is possible to achieve a sufficient It aims at obtaining the manufacturing method of the inexpensive rotary electric machine which can suppress reduction of the iron loss resulting from using a rolled steel plate, the stator core of a rotary electric machine, and a stator core.

A stator core of a rotating electrical machine according to the present invention is configured by alternately laminating electromagnetic steel sheets and cold-rolled steel sheets with organic insulating coatings interposed therebetween, a cylindrical core back part, and an inner peripheral surface of the core back part Extending radially inwardly from the teeth portion arranged at a predetermined pitch in the circumferential direction, and defined by the core back portion and the teeth portion and arranged at a predetermined pitch in the circumferential direction, respectively. A plurality of welded portions each having a slot portion opened on the inner peripheral side and extending from one end to the other end in the stacking direction of the outer peripheral surface of the core back portion are formed on the outer peripheral surface of the core back portion and stacked. The steel plate and the cold-rolled steel plate are joined and integrated. The electromagnetic steel sheet is formed to have a surface roughness of 0.5 μm Hr · m · s or more on both sides, and the cold-rolled steel sheet is made thinner than the electromagnetic steel sheet and has both sides of 0.5 μm Hr · It is formed with a surface roughness of less than m · s, and the organic insulating coating is coated on both surfaces of the electromagnetic steel sheet.

  According to this invention, both sides of the electrical steel sheet are formed with a surface roughness of 0.5 μmHr · m · s or more, and the cold-rolled steel sheet is made thinner than the electrical steel sheet and both sides are 0.5 μmHr. -It is formed with a surface roughness of less than m · s, and an organic insulating coating is coated on both sides of the electrical steel sheet.

Therefore, when the electromagnetic steel plate and the cold rolled steel plate are alternately laminated, a gap is surely formed between the organic insulating coating and the cold rolled steel plate. Thereby, the volatile gas generated from the organic insulating coating at the time of welding is dissipated from the welded portion through the gap, and the occurrence of blowholes in the welded portion is suppressed, and sufficient welding strength is ensured.
In addition, since the organic insulating coating is formed only on the electromagnetic steel sheet, the amount of the insulating coating is reduced, the space factor of the magnetic material is increased, the output of the stator can be improved, and the source of volatile gas is reduced. As a result, the generation of blowholes can be further suppressed, and the amount of organic substances used as a global environmental load can be reduced.

  Further, eddy current loss, which is an individual component of iron loss, is proportional to the square of the plate thickness. Since the thickness of the cold rolled steel sheet is thinner than that of the electromagnetic steel sheet, eddy current loss in the cold rolled steel sheet can be reduced. On the other hand, the hysteresis loss, which is an individual component of iron loss, does not depend on the plate thickness, but depends on the crystal grain size and the surface roughness of the steel plate surface. In other words, the hysteresis loss does not increase even if the plate thickness is reduced unless the plate thickness is reduced to about the crystal grain size. Since the surface of the cold-rolled steel sheet is prepared as a smooth surface, an increase in hysteresis loss in the cold-rolled steel sheet can be suppressed. Furthermore, since the surface of the cold-rolled steel sheet is made smooth, compared with the case where the surface roughness of the cold-rolled steel sheet is given the same degree of surface roughness as that of the electromagnetic steel sheet, The decrease in magnetic susceptibility is small.

  Thus, by making the thickness of the cold rolled steel sheet thinner than the thickness of the electromagnetic steel sheet and making the surface of the cold rolled steel sheet a smooth surface, the use of the cold rolled steel sheet having inferior magnetic properties compared to the electromagnetic steel sheet It is possible to suppress an increase in iron loss and a decrease in magnetization characteristics due to it.

  FIG. 1 is a perspective view showing a stator iron core of an automotive alternator according to an embodiment of the present invention, and FIG. 2 is a schematic diagram showing a stator iron core of an automotive alternator according to an embodiment of the present invention. FIG.

  1 and 2, the stator core 1 has a cylindrical core back portion 2 and is radially extended inward from the inner peripheral surface of the core back portion 2 and arranged at an equiangular pitch in the circumferential direction. And a slot portion 4 which is defined by the core back portion 2 and the tooth portion 3 and arranged at an equiangular pitch in the circumferential direction and which opens to the inner circumferential side. The stator core 1 is made into a cylindrical shape by abutting the end faces of two semi-cylindrical laminated cores 5 and 5 and integrating them by laser welding. The welded portion 6a that connects the two laminated cores 5 and 5 is formed on the outer peripheral surface of each butted portion 7 of the laminated cores 5 and 5 so as to extend from one end to the other end in the stacking direction.

  In the laminated iron core 5, the magnetic steel sheet 9 and the cold-rolled steel sheet 11 are alternately laminated by connecting the core back part 2 with the crimping part 12 through the edge coating 10 of the electromagnetic steel sheet 9, and further laminating the outer peripheral surface thereof. It is integrated by laser welding so as to extend from one end of the direction to the other end. Here, the welds 6b that connect the laminated electromagnetic steel sheets 9 and the cold rolled steel sheets 11 are circumferentially arranged on the outer peripheral surface of the laminated core 5 so as to reach from one end to the other end in the lamination direction of the laminated core 5, respectively. Three strips are formed at a predetermined pitch.

  Both surfaces of the electromagnetic steel sheet 9 are dull-finished (the surface of the steel sheet is roughened and the surface of the steel sheet has no matte gloss). Then, for example, an organic insulating coating 10 such as an epoxy resin and a modified product thereof, a phenol resin and a modified product thereof, an acrylic resin and a copolymer thereof is coated on both surfaces of the electrical steel sheet 9. Moreover, the cold rolled steel sheet 11 is made of, for example, an SPCC material, finished to a smooth surface, and is not covered with an insulating coating. Here, the electromagnetic steel sheet 9 is dull-finished with an uneven surface having a surface roughness of 0.5 μmHr · m · s or more, and the cold-rolled steel plate 11 is a smooth surface having a surface roughness of less than 0.5 μmHr · m · s. It is finished. Further, the thickness t1 of the electromagnetic steel plate 9 is thicker than the thickness t2 of the cold rolled steel plate 11.

  Since the stator core 1 configured in this manner is produced by alternately laminating the electromagnetic steel plates 9 and the cold rolled steel plates 11 with the insulating coatings 10 interposed therebetween, the iron core formed by laminating only the electromagnetic steel plates 9 is used. Compared to, the price can be significantly reduced. Moreover, since the insulating coating 10 is coat | covered on both surfaces of the electromagnetic steel plate 9, the resistance between the electromagnetic steel plate 9 and the cold rolled steel plate 11 is maintained in a large state, and generation | occurrence | production of an eddy current is suppressed.

  Moreover, since both surfaces of the electromagnetic steel sheet 9 are dull-finished and both surfaces of the cold rolled steel sheet 11 are made to be smooth surfaces, between the electromagnetic steel sheet 9 covered with the insulating coating 10 and the cold rolled steel sheet 11 The gap is reliably formed due to the difference in surface roughness. Therefore, when the butted portions 7 of the laminated iron cores 5 and 5 are welded and integrated, and when the electromagnetic steel sheet 9 and the cold rolled steel sheet 11 laminated with the laminated iron core 5 are welded and integrated, they are generated from the insulating coating 10. The volatile gas to be discharged is dissipated from the periphery of the welded portions 6a and 6b through the gap, and the occurrence of blow holes in the welded portions 6a and 6b is suppressed. Therefore, a decrease in welding strength due to the occurrence of blowholes is suppressed, and even if the stator core 1 is applied to a vehicle AC generator, a situation in which the stator core 1 is damaged is avoided.

  Further, since the insulating coating 10 is formed only on the electromagnetic steel sheet 9, compared to the case where the insulating coating 10 is coated on both the electromagnetic steel sheet 9 and the cold-rolled steel sheet 11, the insulating coating 10 that is a generation source of volatile gas. And the generation of blowholes at the welds 6a and 6b is further suppressed. Further, as the amount of the insulating coating 10 is reduced, the space factor of the magnetic material in the stator core 1 is increased, and the output can be increased. Furthermore, it is possible to reduce the amount of organic substances used as a burden on the global environment.

  Eddy current loss, which is an individual component of iron loss, is proportional to the square of the plate thickness. Since the thickness t2 of the cold rolled steel sheet 11 is thinner than the thickness t1 of the electromagnetic steel sheet 9, the eddy current loss in the cold rolled steel sheet 11 can be reduced. Moreover, the hysteresis loss, which is an individual component of iron loss, does not depend on the plate thickness, but depends on the crystal grain size and the surface roughness of the steel plate surface. In other words, the hysteresis loss does not increase even if the plate thickness is reduced unless the plate thickness is reduced to about the crystal grain size. Since the surface of the cold-rolled steel sheet 11 is made to be a smooth surface, an increase in hysteresis loss in the cold-rolled steel sheet 11 can be suppressed. Furthermore, since the surface of the cold-rolled steel plate 11 is made to be a smooth surface, the surface of the cold-rolled steel plate 11 has a surface roughness comparable to that of the electromagnetic steel plate 9 compared with the case of the cold-rolled steel plate 11. Decrease in magnetization characteristics (permeability) is small.

  Thus, the thickness t2 of the cold rolled steel sheet 11 is made thinner than the thickness t1 of the electromagnetic steel sheet 9, the surface of the electromagnetic steel sheet 9 is made rough, and the surface of the cold rolled steel sheet 11 is made smooth. Compared with the case where the thickness t2 of the rolled steel plate 11 is thicker than the thickness t1 of the electromagnetic steel plate 9, the surface of the electromagnetic steel plate 9 is a smooth surface, and the surface of the cold rolled steel plate 11 is a rough surface, the magnetic properties compared to the electromagnetic steel plate 9. The increase in eddy current loss, the increase in iron loss, and the decrease in the magnetization characteristics due to the use of the cold-rolled steel plate 11 that is inferior can be suppressed. Therefore, when the stator core 1 is mounted on a vehicle AC generator, high-frequency loss during high-speed operation can be suppressed.

  Thus, according to the present invention, it is possible to design in consideration of the balance between the magnetic characteristics of the electromagnetic steel sheet 9 and the cold rolled steel sheet 11 and the generator specifications. Furthermore, although the magnetic properties are inferior to those of the electromagnetic steel sheet 9, it is possible to use the cold-rolled steel sheet 11 at a low material cost, thereby reducing the price of the stator core 1.

  Here, for example, as described in “Iron and Steel” (Vol.66 (8), p.240, 1980), the surface roughness of the electrical steel sheet should be 0.5 μmHr · m · s or more. Thus, good weldability without blowholes is ensured. Also, for example, as the surface roughness of the electromagnetic steel sheet increases, the magnetic properties such as magnetic flux density decrease, so the upper limit of the surface roughness of the electromagnetic steel sheet is determined in consideration of the required performance of the stator core. .

  Next, a method for manufacturing the stator core 1 will be described with reference to FIGS. FIG. 3 is a diagram for explaining a magnetic piece punching step in the method for manufacturing a stator core of a vehicle alternator according to an embodiment of the present invention, and FIG. 4 is a vehicle according to an embodiment of the present invention. FIG. 5 is a plan view showing a laminated material in a method for manufacturing a stator core of an AC generator for a vehicle, and FIG. 5 is a main part showing a laminated material in a method for manufacturing a stator core of a vehicle AC generator according to an embodiment of the present invention FIG. 6 is a cross-sectional view, FIG. 6 is a plan view showing a magnetic piece in a method for manufacturing a stator core of a vehicle AC generator according to an embodiment of the present invention, and FIG. 7 is a vehicle AC according to an embodiment of the present invention. FIG. 8 is a cross-sectional view of a main part showing a magnetic piece in a method of manufacturing a stator core of a generator, and FIG. FIG. 9 is a perspective view showing an embodiment of the present invention. The perspective view which shows the laminated body after the laser welding in the manufacturing method of the stator core of the alternating current generator for vehicles which concerns on a state, FIG. 10 is manufacture of the stator core of the alternating current generator for vehicles which concerns on one embodiment of this invention. FIG. 11 is a perspective view showing a stator core around which a stator winding is wound in a method for manufacturing a stator core of a vehicle alternator according to an embodiment of the present invention. It is.

  First, a first strip steel material 20 in which an insulating coating 22 made of an organic insulating resin is coated on both surfaces of a 0.5 mm thick electromagnetic steel material 21 dull-finished to a surface roughness of 0.5 μmHr · m · s or more. Winding drum 30 and a second belt-like steel material 23 made of a cold rolled steel material having a thickness of 0.35 mm and finished to a smooth surface with a surface roughness of less than 0.5 μmHr · m · s A drum 31 is prepared.

  And as FIG. 3 shows, the 1st strip | belt-shaped steel material 20 and the 2nd strip | belt-shaped steel material 23 which were drawn | fed out from each of the winding drums 30 and 31 are twisted yarn which consists of thermoplastic resins, such as nylon 6 and nylon 66, for example. 24 is applied and stacked, passed through the pressure roller 32, and introduced into the induction heating furnace 33. The twisted yarn 24 is heated to, for example, 200 ° C. and melted in the induction heating furnace 33. Next, the superposed first and second strip steel materials 20 and 23 are passed through the cooling roller 34 and sent to the press machine 35. Here, the melted twisted yarn 24 is crushed by the cooling roller 34 and is cooled and solidified. Thereby, the 1st and 2nd strip | belt-shaped steel materials 20 and 23 which were piled up become the laminated material 25 which adhere | attached and integrated in the close state, as FIG. 5 shows. Here, for example, as shown in FIG. 5, the twisted yarn 24 is applied while avoiding a press punching region such as between the press punching position of the pilot hole 26 and the press punching position of the magnetic piece 13.

  In the press machine 35, as shown in FIG. 4, the pilot holes 26 are punched at a predetermined pitch in the length direction on both sides in the width direction of the laminated material 25 (S 1). The portion 12 is recessed (S2). Next, the slot 4a is punched (S3), the regions 16 at both ends in the length direction of the magnetic piece 13 are punched (S4), and the regions 17 on both sides in the length direction of the magnetic piece 13 are punched (S5). ). Thereby, the magnetic piece 13 is punched out from the laminated material 25. As shown in FIG. 3, the laminated material 25 from which the magnetic pieces 13 have been punched is introduced into an induction heating furnace 36, and the solidified twisted yarn 24 is melted. Subsequently, the 1st strip | belt-shaped steel material 20 and the 2nd strip | belt-shaped steel material 23 are isolate | separated, and it winds up by the winding drums 37 and 38, respectively, and uses for recycling of a remaining material.

  As shown in FIGS. 6 and 7, the magnetic piece 13 punched from the laminated material 25 is an electrical steel sheet 9 that is the first magnetic piece covered with the insulating coating 10 (insulating coating 22) punched in the same shape. And a cold-rolled steel plate 11 which is the second magnetic piece are integrally fixed by a caulking portion 12. The electromagnetic steel sheet 9 and the cold-rolled steel sheet 11 have a rectangular shape having a length that is half of the entire circumferential length of the stator core 1, and the teeth portion 3 a is from one side in the width direction of the core back portion 2 a. Protruding and arranged at a predetermined pitch in the length direction of the core back portion 2a. The slot portion 4a is defined by the core back portion 2a and the teeth portion 3a.

  Then, the core back portion 2a, the teeth portion 3a, and the slot portion 4a are overlapped, and fixed to each other by the caulking portion 12, and a predetermined number of magnetic pieces 13 are stacked, and as shown in FIG. A body 14 is produced. At this time, the core back part 2a, the tooth part 3a, and the slot part 4a are connected in the stacking direction, and the core back part 2, the tooth part 3, and the slot part 4 are configured, respectively. Next, the outer peripheral surface of the core back portion 2 of the laminated body 14 is laser welded so as to reach from one end to the other end in the laminating direction, and the laminated electromagnetic steel plates 9 and the cold rolled steel plates 11 are connected and integrated. As a result, three welds 6b extending from one end to the other end in the stacking direction are formed on the outer peripheral surface of the core back portion 2 of the stacked body 14, as shown in FIG.

  Next, the cuboid laminate 14 is subjected to semicircular rounding to produce two semicylindrical laminated cores 5 as shown in FIG. And the end surfaces of the two laminated cores 5 are butted together, laser welding is performed on the outer peripheral surface of the butted portion 7 so as to reach from the one end to the other end in the laminating direction, and the laminated cores 5 and 5 that are butted together are connected and integrated. The stator core 1 is manufactured. As a result, a welded portion 6 a extending from one end to the other end in the stacking direction is formed on the outer peripheral surface of the butted portion 7 of the stator core 1. Here, although not shown, the laminated iron cores 5 and 5 are abutted with the stator windings 15 being mounted, and are connected and integrated by laser welding. As a result, as shown in FIG. 11, the stator core 1 is manufactured, and at the same time, the stator winding 15 is wound around the stator core 1. Then, a predetermined connection process is performed on the stator winding 15 to produce a stator.

  Although not illustrated, the stator manufactured in this way is incorporated in the housing so as to surround the rotor that is rotatably disposed in the housing of the AC generator for vehicles. When the rotor is driven to rotate, a rotating magnetic field is applied to the stator winding 15 of the stator, and an electromotive force is generated in the stator winding 15.

  According to the present invention, the magnetic strip 13 is produced by punching the laminated material 25 formed by bonding and integrating the first strip steel material 20 and the second strip steel material 23 using the twisted yarn 24. The positional deviation between the first strip steel material 20 and the second strip steel material 23 is suppressed, the processing accuracy is improved, and the electromagnetic steel plate 9 and the cold rolled steel plate 11 constituting the magnetic piece 13 are simultaneously punched. , Productivity is increased. In a rectangular parallelepiped laminate 14 in which a predetermined number of magnetic pieces 13 are laminated, electromagnetic steel plates 9 and cold rolled steel plates 11 are alternately laminated, and the thickness of the electromagnetic steel plates 9 is made thicker than that of the cold rolled steel plates 11. For this reason, the rigidity of the magnetic piece 13 is higher than that in the case where the rectangular parallelepiped laminated body 14 is constituted by only the cold-rolled steel sheet 11 having a thin plate thickness, and deformation in the laminating direction when semicircular rounding is performed can be suppressed. Thus, a semi-cylindrical laminated iron core 5 with good shape accuracy can be produced.

Since the twisted yarn 24 is disposed so as to avoid the punching region of the magnetic piece 13, the twisted yarn 24 does not exist in the magnetic piece 13. Therefore, the application of the twisted yarn 24 does not cause a situation in which gas is generated during laser welding to reduce the bonding strength. Further, the application of the twisted yarn 24 does not cause a situation in which gas is generated during the annealing process described later to oxidize the magnetic steel sheet 9 and the cold-rolled steel sheet 11 to deteriorate the magnetic properties.
Further, since the twisted yarns 24 are arranged so as to avoid press punching regions such as the pilot holes 26 and the magnetic pieces 13, the wear of the mold can be reduced.

After the magnetic piece 13 is punched out, the laminated material 25 is passed through the induction heating furnace 36 to melt the solidified twisted yarn 24 and is separated from the first belt-shaped steel material 20 and the second belt-shaped steel material 23. It becomes easy to separate and recycle.
As described above, the first strip steel material 20 and the second strip steel material 23 can be easily integrated and separated only by arranging the induction heating furnaces 33 and 36 before and after the press machine 35. A general-purpose facility can be used as it is, and the manufacturing process can be constructed with a small capital investment.

  In the above embodiment, the magnetic piece is made to be half the total circumferential length of the stator core, but the length of the magnetic piece is the entire circumferential length of the stator core. The length is not limited to half the circumferential length, and may be, for example, a length equal to the entire circumferential length of the stator core. In this case, the stator winding is attached to the laminate produced by laminating a predetermined number of magnetic pieces, and the laminate to which the stator winding is attached is rounded into a round shape, and the rounding step In addition, the welding process of the butt portion can be performed only once, and the production process can be simplified.

  Further, in the above embodiment, the magnetic strips are punched out by stacking and integrating the first strip steel material and the second strip steel material, and the magnetic strips are stacked. However, the electromagnetic steel plate is punched out from the first strip steel material. Similarly, a cold rolled steel plate may be punched from the second strip steel material, and the punched electromagnetic steel plate and the cold rolled steel plate may be alternately laminated.

Next, the magnetic anisotropy of the electrical steel sheet will be examined.
As the grade of the electrical steel sheet increases, a magnetic property difference (magnetic anisotropy with respect to the rolling direction) occurs in the steel sheet surface with respect to the rolling direction. The stator core in the generator includes a tooth part and a core back part between the tooth parts in a rolling direction (L direction) of the steel sheet and a direction (C direction) perpendicular to the rolling direction. And the smaller the difference in magnetic properties in both directions (the more isotropic material), the better the magnetic balance over the entire circumference of the stator core, leading to improved performance.

  Here, four types of electrical steel sheets (sheet thickness: 0.5 mm) of JIS 50H290, 50A470, 50A600, 50A1300 are prepared, and the maximum ratio between the L direction and the C direction of each electrical steel sheet using the Epstein test of JIS C2550. The results of measuring the permeability ratio are shown in FIG. In FIG. 12, the vertical axis represents the magnetic anisotropy in the plane of the electrical steel sheet defined by the relative permeability ratio in the L direction with respect to the C direction, and the horizontal axis represents silicon (Si ) And aluminum (Al) content (weight%). The total content of Si and Al represents the grade of the electrical steel sheet, and the total content increases as the grade of the electrical steel sheet increases. And the total content of Si and Al of the electrical steel sheet of JIS 50A1300 is about 0.1% by weight.

FIG. 12 shows that when the total content of Si and Al exceeds 1.5% by weight, the magnetic anisotropy in the L direction increases rapidly. Therefore, from the viewpoint of reducing the magnetic anisotropy required for the stator core material, it is preferable to suppress the total content of Si and Al to 1.5% by weight or less. Moreover, when the total content of Si and Al exceeds 1.5% by weight, the mechanical properties such as the yield point and elongation of the electrical steel sheet are greatly deviated from the mechanical properties of the cold rolled steel sheet, and the laminate The rounding workability of the is reduced.
For these reasons, it is preferable to use a grade electrical steel sheet having a total content of Si and Al of 1.5% by weight or less for the present stator core.

Next, the annealing effect of the cold rolled steel sheet will be examined.
Here, a predetermined number of cold-rolled steel plates are laminated to produce two rectangular parallelepiped laminates, and each rectangular parallelepiped laminate is subjected to semicircular rounding to produce two semicylindrical laminated cores. Two laminated cores were butted and integrated to prepare a cylindrical unannealed stator core. Further, a predetermined number of cold-rolled steel sheets are laminated to produce a laminate of two rectangular parallelepipeds, and each of the rectangular parallelepiped laminates is subjected to an annealing treatment (for example, 600 ° C.), and each of the rectangular parallelepiped laminates subjected to the annealing treatment The body was subjected to semicircular rounding to produce two semi-cylindrical laminated iron cores, and the two laminated iron cores were butted together to prepare a cylindrical first stator core. Furthermore, a predetermined number of cold-rolled steel sheets are laminated to produce two rectangular parallelepiped laminates, each of the rectangular parallelepiped laminates is semi-rounded to produce two semicylindrical laminated iron cores, and each laminated iron core Were subjected to annealing treatment (for example, 600 ° C.), and two laminated iron cores subjected to the annealing treatment were butted and integrated to prepare a cylindrical second stator core.

  And the coil | winding for a measurement is wound around each of an unannealed and 1st and 2nd stator core, and the result of having measured the hysteresis loss of a core back part is shown in FIG. In FIG. 13, the vertical axis represents the rate of change of hysteresis loss in the first and second stator cores relative to the hysteresis loss of the unannealed stator core, and the horizontal axis represents the magnetic flux density.

  From FIG. 13, it can be seen that in the second stator core, the hysteresis loss can be reduced by about 60% with respect to the unannealed stator core. This effect is presumed to be due to the fact that the influence of rounding or the like has disappeared by the annealing treatment. It can also be seen that the hysteresis loss of the first stator core can be reduced by about 30% with respect to the unannealed stator core. Thereby, it was confirmed that the effect of the annealing treatment remains even in the stator core subjected to the annealing treatment before the rounding.

  As described above, the cold rolled steel sheet is subjected to a heat treatment (annealing treatment) at a recrystallization temperature or higher (for example, 600 ° C. or higher), thereby recovering work distortion and work deformed crystal grains, and originally fine crystal grains. Regrows to increase the particle size. As a result, it is assumed that the magnetic properties of the cold-rolled steel sheet, particularly the magnetization properties and the hysteresis loss were improved. For this reason, the electrical steel sheet may be subjected to heat treatment (annealing treatment) at a recrystallization temperature or higher (for example, 600 ° C. or higher). As a result, even in electrical steel sheets, work strain and deformed crystal grains are recovered, and originally fine crystal grains re-grow to a large grain size, improving the magnetic properties of magnetic steel sheets, particularly the magnetization characteristics and hysteresis loss. Is planned.

  From these things, it is preferable to perform an annealing process to the laminated body before a rounding process, or the laminated core after a rounding process in the manufacture process of a stator core. Thereby, the cold-rolled steel sheet and the electromagnetic steel sheet that are stacked are heat-treated at the same time, and the effect of reducing the magnetic property difference between the cold-rolled steel sheet and the electromagnetic steel sheet is obtained.

  In the above-described embodiment, the stator iron core of the vehicle alternator has been described. However, the present invention is not limited to the vehicle alternator, and is not limited to the vehicle alternator. You may apply to a stator core and may apply to the stator core of rotary electric machines other than for vehicles.

  Moreover, in the said embodiment, a rectangular magnetic piece is punched out from what laminated | stacked and integrated the 1st strip | belt-shaped steel material and the 2nd strip | belt-shaped steel material, the magnetic piece was laminated | stacked, the laminated | stacked magnetic piece was welded, and integrated, and a rectangular parallelepiped And then stacking the rectangular parallelepiped to produce an arc-shaped laminated iron core, butting the end faces of the arc-shaped laminated iron core, welding the butted parts to form a cylindrical stator core Although it is supposed to be produced, a long magnetic piece is punched out from the laminated and integrated first and second steel strips, the magnetic piece is spirally wound, and the wound magnetic piece is welded. A cylindrical stator iron core may be produced by integration.

  Furthermore, in the said embodiment, a rectangular magnetic piece is punched out from what laminated | stacked and integrated the 1st strip | belt-shaped steel material and the 2nd strip | belt-shaped steel material, the magnetic piece was laminated | stacked, the laminated | stacked magnetic piece was welded, integrated, and a rectangular parallelepiped A laminated body is manufactured, a rectangular parallelepiped laminated body is rounded to produce an arc-shaped laminated iron core, end faces of the arc-shaped laminated iron core are butted together, and the butted portions are welded to produce a cylindrical stator core. The first and second strip steel materials are laminated and integrated, and the arc-shaped magnetic pieces are punched out. The arc-shaped magnetic pieces are laminated and the laminated magnetic pieces are welded and integrated. An arc-shaped laminated iron core may be produced, the end faces of the arc-shaped laminated iron core may be butted together, and the abutted portion may be welded to produce a cylindrical stator iron core. The magnetic pieces laminated Contact may be produced a cylindrical stator core and integrated.

It is a perspective view which shows the stator core of the alternating current generator for vehicles which concerns on one embodiment of this invention. It is a principal part expanded sectional view which shows the stator core of the alternating current generator for vehicles which concerns on one embodiment of this invention. It is a figure explaining the punching process of the magnetic piece in the manufacturing method of the stator core of the alternating current generator for vehicles concerning one embodiment of this invention. It is a top view which shows the laminated material in the manufacturing method of the stator core of the alternating current generator for vehicles which concerns on one embodiment of this invention. It is principal part sectional drawing which shows the laminated material in the manufacturing method of the stator core of the alternating current generator for vehicles which concerns on one embodiment of this invention. It is a top view which shows the magnetic piece in the manufacturing method of the stator core of the alternating current generator for vehicles which concerns on one embodiment of this invention. It is principal part sectional drawing which shows the magnetic piece in the manufacturing method of the stator core of the alternating current generator for vehicles which concerns on one embodiment of this invention. It is a perspective view which shows the laminated body before the laser welding in the manufacturing method of the stator core of the alternating current generator for vehicles which concerns on one embodiment of this invention. It is a perspective view which shows the laminated body after the laser welding in the manufacturing method of the stator core of the alternating current generator for vehicles which concerns on one embodiment of this invention. It is a perspective view which shows the laminated iron core in the manufacturing method of the stator iron core of the alternating current generator for vehicles which concerns on one embodiment of this invention. It is a perspective view which shows the stator core by which the stator coil | winding was wound in the manufacturing method of the stator core of the alternating current generator for vehicles which concerns on one embodiment of this invention. It is a figure which shows the relationship between (Si + Al) content in a magnetic steel plate in the stator iron core of the alternating current generator for vehicles concerning one embodiment of this invention, and magnetic anisotropy. It is a figure which shows the relationship between the magnetic flux density of the iron core in the stator core of the alternating current generator for vehicles which concerns on one embodiment of this invention, and the change rate of a hysteresis loss.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Stator iron core, 2 Core back part, 3 teeth part, 4 slot part, 5 laminated iron core, 6a, 6b welded part, 7 butt | matching part, 9 Magnetic steel plate (1st magnetic piece), 10 Insulating film, 11 Cold rolling Steel plate (second magnetic piece), 13 magnetic piece, 14 laminate, 15 stator winding, 20 first strip steel, 21 electromagnetic steel, 22 insulating coating, 23 second strip steel, 24 twisted yarn (thermoplastic resin), 25 Laminated material.

Claims (7)

The electromagnetic steel plate and the cold rolled steel plate are alternately laminated via an organic insulating coating, and are formed in a cylindrical core back part, extending radially inward from the inner peripheral surface of the core back part, Teeth portions arranged at a predetermined pitch in the circumferential direction, and slot portions defined by the core back portion and the teeth portions and arranged at a predetermined pitch in the circumferential direction, each opening to the inner peripheral side A plurality of welds extending from one end to the other end in the stacking direction of the outer peripheral surface of the core back portion are formed on the outer peripheral surface of the core back portion, and the laminated electromagnetic steel plate and the cold rolled steel plate are joined together. A stator core of a rotating electric machine,
The electromagnetic steel sheet is formed to have a surface roughness of 0.5 μmHr · m · s or more on both sides,
The cold-rolled steel sheet is made thinner than the electromagnetic steel sheet, and both surfaces are formed with a surface roughness of less than 0.5 μm Hr · m · s,
A stator core for a rotating electric machine, wherein the organic insulating coating is coated on both surfaces of the electromagnetic steel sheet. It has a butt portion between the end faces of the laminated electromagnetic steel sheet and the cold rolled steel sheet,
The stator iron core for a rotating electrical machine according to claim 1, wherein at least one of the welded portions is formed on an outer peripheral surface of the butted portion of the core back portion.   The stator core for a rotating electrical machine according to claim 1 or 2, wherein the total content of Si and Al in the electromagnetic steel sheet is 1.5% by weight or less. A core back portion, a tooth portion, and a slot portion are formed from a first strip steel material in which both surfaces of an electromagnetic steel material having a surface roughness of 0.5 μmHr · m · s or more are coated with an organic insulating coating. A first punching step of punching the rectangular first magnetic piece formed,
A second punching step of punching a second magnetic piece having the same shape as the first magnetic piece from a second strip steel material made of cold-rolled steel having a surface roughness of less than 0.5 μm Hr · m · s;
A steel plate laminating step of alternately laminating the first magnetic pieces and the second magnetic pieces to produce a rectangular parallelepiped laminate;
Welding the side surfaces of the cuboid laminate so as to reach the other end from one end in the stacking direction;
A step of rounding the welded laminated body of the rectangular parallelepiped to produce an arc-shaped or circular cylindrical laminated core; and
A method of manufacturing a stator core of a rotating electrical machine, comprising: abutting end faces of the laminated core together and welding an outer peripheral surface of the butted portion so as to reach from one end to the other end in the laminating direction. The first and second punching steps are:
A thermoplastic resin is disposed between the first strip steel material and the second strip steel material by removing the punched areas of the first magnetic piece and the second magnetic piece, and then melting and solidifying the thermoplastic resin. Laminating and integrating the first strip steel and the second strip steel; and
A stamping step of punching a pair of the first magnetic piece and the second magnetic piece from the integrated first and second steel strips; and
5. The stator for a rotating electrical machine according to claim 4, wherein, in the steel plate laminating step, the rectangular parallelepiped laminate is produced by laminating a pair of the punched first magnetic piece and the second magnetic piece. Manufacturing method of iron core.   The method further comprises an annealing step of heat-treating the welded laminated body of the rectangular parallelepiped or the rounded laminated iron core at a temperature exceeding a recrystallization temperature of the electromagnetic steel material and the cold-rolled steel material. The manufacturing method of the stator core of the rotary electric machine of Claim 4 or Claim 5 to do. A stator having the stator core according to any one of claims 1 to 3, and a stator winding wound around the stator core,
A rotating electrical machine comprising: a rotor rotatably disposed on an inner diameter side of the stator.

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